Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION 

 

DECEMBER 10, 2007 1

 

 WORLD BANK GROUP

Environmental, Health and Safety Guidelines 

for Large Volume Inorganic Compounds

 Manufacturing and Coal Tar Distillation

Introduction

The Environmental, Health, and Safety (EHS) Guidelines are 

technical reference documents with general and industryspecific examples of Good International Industry Practice 

(GIIP)1. When one or more members of the World Bank Group 

are involved in a project, these EHS Guidelines are applied as 

required by their respective policies and standards. These 

industry sector EHS guidelines are designed to be used 

together with the General EHS Guidelines document, which 

provides guidance to users on common EHS issues potentially 

applicable to all industry sectors. For complex projects, use of 

multiple industry-sector guidelines may be necessary. A 

complete list of industry-sector guidelines can be found at: 

www.ifc.org/ifcext/enviro.nsf/Content/EnvironmentalGuidelines

The EHS Guidelines contain the performance levels and 

measures that are generally considered to be achievable in new 

facilities by existing technology at reasonable costs. Application 

of the EHS Guidelines to existing facilities may involve the 

establishment of site-specific targets, with an appropriate 

timetable for achieving them. 

The applicability of the EHS Guidelines should be tailored to the 

hazards and risks established for each project on the basis of 

 

1 Defined as the exercise of professional skill, diligence, prudence and foresight 

that would be reasonably expected from skilled and experienced professionals 

engaged in the same type of undertaking under the same or similar 

circumstances globally. The circumstances that skilled and experienced 

professionals may find when evaluating the range of pollution prevention and 

control tec hniques available to a project may include, but are not limited to, 

varying levels of environmental degradation and environmental assimilative 

capacity as well as varying levels of financial and technical feasibility.

the results of an environmental assessment in which sitespecific variables, such as host country context, assimilative 

capacity of the environment, and other project factors, are taken 

into account. The applicability of specific technical 

recommendations should be based on the professional opinion 

of qualified and experienced persons. When host country 

regulations differ from the levels and measures presented in the 

EHS Guidelines, projects are expected to achieve whichever is 

more stringent. If less stringent levels or measures than those 

provided in these EHS Guidelines are appropriate, in view of 

specific project circumstances, a full and detailed justification for 

any proposed alternatives is needed as part of the site-specific 

environmental assessment. This justification should 

demonstrate that the choice for any alternate performance 

levels is protective of human health and the environment.

Applicability

This EHS Guideline includes information relevant to chemical

manufacturing projects and facilities, and covers the production 

of large volume inorganic compounds (LVIC), including

ammonia, acids (nitric, hydrochloric, sulfuric, hydrofluoric, 

phosphoric acid), chlor-alkali (e.g. chlorine, caustic soda, soda 

ash, etc.), carbon black, and coal tar distillation (naphthalene, 

phenanthrene, anthracene). This document is organized 

according to the following sections:

Section 1.0 — Industry-Specific Impacts and Management

Section 2.0 — Performance Indicators and Monitoring 

Section 3.0 — References and Additional Sources

Annex A — General Description of Industry Activities
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 2

 

 WORLD BANK GROUP

1.0 Industry-Specific Impacts 

and Management

The following section provides a summary of EHS issues 

associated with facilities manufacturing large volume inorganic 

compounds (LVIC) and for coal tar distillation, which occur 

during the operational phase, along with recommendations for 

their management. 

Recommendations for the management of EHS impacts 

common to most large industrial facilities during the construction 

and decommissioning phases are provided in the General EHS 

Guidelines. 

1.1 Environmental

Typical environmental issues associated with LVIC

manufacturing include the following: 

• Air emissions

• Liquid effluents

• Generation of solid waste

• Hazardous materials management

• Noise

• Odors

• Decommissioning

Air Emissions

The manufacture and use of inorganic chemicals and chemical 

products typically generate s large volume of emissions; 

however, current technology allows for closed system 

operations, thus significantly reducing emission releases to the 

environment. 

Emission sources from chemical processes include process tail 

gases, heaters and boilers; valves, flanges, pumps, and 

compressors; storage and transfer of raw materials, products 

and intermediates; waste water handling; flares; and emergency 

vents.

Although chemical manufacturing emissions vary depending on 

the specific process and related feedstok, the most common 

pollutants that may be emitted from point or fugitive sources 

during routine operations, include: carbon dioxide (CO2),

nitrogen oxides (NOX), sulfur oxides (SOX), ammonia (NH3), 

acids and acid mists, chlorine gas, and dust. Volatile organic 

compounds and tar fume are emitted from carbon black and 

coal tar distillation plants. 

The gaseous emissions from the chemical manufacturing

industry can be typically controlled by adsorption or absorption. 

Parti culate emissions, usually less than 10 mi crons in 

aerodynamic diameter, are controlled by highly efficient systems 

such as bag filters, electrostatic precipitators, etc.

Chemical manufacturing facilities are large consumer of energy. 

Exhaust gas emissions produced by the combustion of gas or 

other fuels in turbines, boilers, compressors, pumps and other 

engines for power and heat generation, are a significant source 

of mainly CO2 and NOX. Guidance for the management of 

small combustion source emissions with a capacity of up to 50 

megawatt hours thermal (MWth), including air emission 

standards for exhaust emissions, is provided in the General 

EHS Guidelines. Guidance for the management of combustion 

source emissions from larger sources of power generation is 

provided in the EHS Guidelines for Thermal Power. 

Greenhouse Gases (GHGs)

The LVIC manufacturing industry is a significant emitter of 

greenhouse gases, especially carbon dioxide (CO2). GHGs are 

generated from the process as well as during the production of 

its highly demanding energy needs. Measures to increase 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 3

 

 WORLD BANK GROUP

energy efficiency and installation of Low NOX burners should be 

adopted since they will contribute to reduce CO2 generation.

Attempts should be made to maximize energy efficiency and 

design facilities for lowest energy use. Recommendations on 

energy efficiency are addressed in the General EHS 

Guidelines. 

Fugitive Emissions

Fugitive emissions are associated with leaks from pipes, valves, 

connections, flanges, packings, open-ended lines, floating roof 

storage tank and pump seals, gas conveyance systems, 

compressor seals, pressure relief valves, tanks or open pits / 

containments, and loading and unloading operations of 

products. Due to the presence of hazardous products in LVIC

manufacturing facilities (i.e. NH3 and chlorine), methods for 

controlling and preventing fugitive emissions should be 

considered and implemented in their design, operation, and 

maintenance. The selection of appropriate valves, flanges, 

fittings, seals, and packings should be based on their capacity to 

reduce gas leaks and fugitive emissions.

Use of open vents in tank roofs should be avoided by installing 

pressure relief valves. Storages and unloading stations should 

be provided with vapor recovery units. Vapor processing 

systems may consist of different methods, such as carbon 

adsorption, refrigeration, recycling collecting and burning. 

Examples of measures for reducing the generation of fugitve 

emissions include:

• Rigorous maintenance programs, particularly in stuffing 

boxes on valve stems and seats on relief valves, to reduce 

or eliminate accidental releases;

• Selection of appropriate valves, flanges, fittings;

• Well designed, constructed, operated and maintained 

installations;

• Implementation of leak detection and repair programs;

• Installation of continuous monitoring in all sensitive areas.

Venting and Flaring

Venting and flaring are important safety measures used in 

chemical manufacturing facilities to ensure gas is safely 

disposed of during process start up and shut down or in the 

event of an emergency, power or equipment failure, or other 

plant upset conditions. 

Recommended methods to prevent, minimize, and control air 

emissions from venting and flaring include:

• Use best practices and new technologies to minimize 

releases and potential impacts from venting and flaring 

(e.g., efficient flare tips, reliable pilot ignition system, 

minimization of liquid carry over, control of odor and visible 

smoke emissions, and locating flare at a safe distance from 

potential human and environmental receptors);

• Estimate flaring volumes and develop flaring targets for 

new facilities, and record volumes of gas flared for all 

flaring events;

• Divert gas emissions from emergency or upset conditions 

to an efficient flare gas system. Emergency venting may be 

acceptable under specific conditions where flaring of the 

gas stream is not possible, on the basis of a risk analysis. 

Justification for no gas flaring system should be fully 

documented before an emergency gas venting facility is 

considered.

Process Air Emissions – Ammonia Manufacturing

Process air emissions from ammonia plants consist mainly of 

hydrogen (H2), carbon dioxide (CO2), carbon monoxide (CO), 

and ammonia (NH3). Concentrated carbon dioxide emissions 

are generated from CO2 removal in these facilities. Fugitive 

emissions of NH3 (e.g. from storage tanks, valves, flanges, and 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 4

 

 WORLD BANK GROUP

tubing) may also occur, especially during transport or transfer. 

Non-routine emissions associated with process upsets or 

accidents may contain natural gas, CO, H2, CO2, volatile organic 

compounds (VOCs), nitrogen oxides (NOX) and NH3. 

Recommended emission prevention and control measures 

include the fo llowing:

• Use synthesis NH3 purge gas treatment to recover NH3 and 

H2 before combustion of the remainder in the primary 

reformer;

• Increase the residence time for off-gas in the hightemperature zone; 

• Connect ammonia emissions from relief valves or pressure 

control devices from vessels or tanks to a flare or to a 

water scrubber;

• Combine ammonia and urea facilities to reduce (through 

reuse in urea plant) ammonia process-generated CO2

emissions2. Another industrial alternative is to combine 

with methanol production. It is noted that, in methanol 

production facilities, hydrogen is produced from natural 

gas, by means of a steam reforming unit followed by a 

methanol unit. This process, therefore, does not fully 

eliminate CO2 emissions because of the energy used to run 

the hydrogen production and methanol synthesis units.

Process Air Emissions – Acid Manufacturing 

Process emissions from acid plants include the following:

• Nitrous oxide (N2O) and NOX from nitric acid manufacturing 

plants, particularly from tail gas emissions 3;

 

2 Ammonia process-derived CO2 can be almost totally consumed if the 

produced ammonia is transformed into urea (1t NH3 - 1.5 t urea).

3 The lowestNOX emission levels currently achieved in a modern plant without 

added pollution abatement are between1,000 to 2,000 ppmv for medium 

pressure absorption and 100 to 200 ppmv for high pressure absorption. For new 

plants in normal operating conditions the NOX emission level (excluding N2O) 

• SO2 resulting from incomplete oxidation and SO3 resulting 

from incomplete absorption and droplets of sulfuric acid 

(H2SO4) from sulfuric acid manufacturing plants;

• Gaseous fluorides and dust from phosphoric / hydrofluoric 

acid plants;

• Hydrochloric acid (HCl) gas, chlorine, and chlorinated 

organic compounds resulting primarily from gases exiting 

the HCl purification system in HCl production;

• Fluorine, hydrofluoric acid (HF), and silicon tetrafluoride 

(SiF4) from digestion of phosphate rock and dust from 

handling of phosphate rock in HF production. Particulate 

matter is emitted during handling and drying of the 

fluorspar. In hydrofluoric acid facilities fluorine emissions 

present in the final vents are typically very low following the 

required treatment. 

Recommended emission prevention and control measures 

include the following:

• The plant should be equipped with pre-condensers that 

remove water vapor and sulfuric acid mist, and with 

condensers, acid scrubbers, and water scrubbers that 

minimize the release of HF, SiF4, SO2, and CO2 from the 

tail-gas;

• Use high-pressure adsorption process for nitric acid 

production to minimize the concentration of NOX in the tail 

gas;

• Treat the off-gases from nitric acid plants using catalytic 

NOX removal;

• Consider using double absorption process for H2SO4

plants. Plants operating on a single absorption process 

shouild consider implementation of the following:

o Cesium catalyst in the last bed

 

can be at 100 ppmv, which is equivalent to 0.65kg NOX (expressed as NO2) per 

ton of 100% nitric acid produced.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 5

 

 WORLD BANK GROUP

o SO2 abatement by scrubbing with a neutralizing 

compound

o SO2 abatement with hydrogen peroxide (H2O2)

• Control dust emissions from the flue-gases of directly 

heated dryers and/or from pneumatic conveying gases 

using cyclones and filters;

• Recover the fluorine as fluosilicic acid; a dilute solution of 

fluosilicic acid should be used as the scrubbing liquid. 

Fluorine, released during the digestion of phosphate rock 

and during the concentration of phosphoric acid, should be 

removed by scrubbing systems;

• Control emissions of HF by the condensing, scrubbing, and 

absorption equipment used in the recovery and purification 

of the hydrofluoric and hexafluorosilicic acid products;

• Minimize HF emissions, maintaining a slight negative 

pressure in the kiln during normal operations; 

• Install caustic scrubbers to reduce the levels of pollutants 

in the HF tail-gas, as needed;

• Control dust emissions by bag filters at the fluorspar silos 

and drying kilns. Collect dust from the gas streams exiting 

the kiln in HF production and return the dust to the kiln for 

further processing;

• Control dust emissions from fluorspar handling and storage 

with flexible coverings and chemical additives, and

• Control dust emissions from phosphate rock during 

transport, handling and storage, using enclosed systems 

and bag filters.

Process Air Emissions – Chlor-Alkali Plants

The principal chlor-alkali processes are mercury, diaphragm, 

and membrane cell electrolysis. The most significant emi ssions

from all three processes are both fugitive and point source 

chlorine gas emissions. Sources of potential significant chlorine 

emissions are normally associated with the chlorine destruction 

unit where emissions from non-condensable gases remaining 

from liquefaction (H2, O2, N2, CO2) having a chlorine content 

from 1-8% of the raw chlorine gas produced are treated. Other 

emissions from chlor-alkali plants are linked to the brine 

purification. Air emissions from mercury cell technology include

mercury vapors, emitted as fugitive emissions from the cells 

(e.g. cell room ventilation gas). 

Principal air emissions from soda ash manufacturing are 

process carbon dioxide and particulate emissions from ore 

calciners, soda ash coolers and dryers, ore crushing, screening, 

and transportation operations, product handling and shipping 

operations. Emissions of products of combustion, such as 

carbon monoxide, nitrogen oxides, and sulfur dioxide, occur 

from direct-fired process heating units such as ore calcining 

kilns and soda ash dryers. Ammonia may also be emitted.

Nitrogen oxides are produced in small quantities inside the kiln 

by the oxidation of nitrogen contained in the air used in the 

combustion process, and sulfur oxides by the oxidation of 

compounds containing sulfur in the limestone.

Recommended emission prevention and control measures 

include the fo llowing:

• Discontinue use of mercury and diaphragm cell processes, 

where possible, and adopt new membrane cell process. 

Alternatively, install improved cell part materials (e.g.

dimensionally stable anodes (DSA®), modified diaphragm), 

as needed; 

• Prepare mercury mass balances to account for all mercury 

use;

• Optimize process to keep the cells as close as possible;

• Install mercury distillation units to recover mercury;

• Ensure that that the mercury cell end boxes and caustic 

boxes are properly sealed, thus eliminating fugitive 

releases;
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 6

 

 WORLD BANK GROUP

• Design the chlorine absorption unit with a treatment 

capacity sufficient to absorb the full cell-room production 

and prevent emissions of chlorine gas in the event of a 

process upset until the plant can be shut down. The 

absorption unit should be designed to lower the chlorine 

content in the emitted gas to less than 5 mg/m3 in the worst 

case scenario;

• Direct all chlorine-containing waste gas streams to the 

chlorine absorption unit and ensure that the system is gas 

tight;

• Install chlorine gas detectors in areas with a potential risk 

of chlorine leaks to allow for immediate leakage detection;

• Use carbon tetrachloride-free chlorine liquefaction and

purification processes. The use of carbon tetrachloride 

(CCl4), for removal of nitrogen trichloride (NCl3) and for 

absorption of tail gas, should be avoided and discontinued; 

• In soda ash facilities, control particulate emissions from ore 

and product handling operations by either venturi 

scrubbers, or baghouse filters, electrostatic precipitators, 

and/or cyclones and recycle the collected particulates. 

Process Air Emissions – Carbon Black Manufacturing 

An important potential source of emission to air is the tail gas 

coming from the reactor after carbon black separation, which is 

a low calorific gas with a high moisture content due to the 

quench water vapor. The tail-gas composition may vary 

considerably according to the grade of carbon black being 

produced and the feedstock used. It may contain H2, CO, CO2, 

reduced sulfur compounds (H2S, CS2 and COS), SO2, nitrogen 

compounds (N2, NOX, HCN and NH3), VOCs such as ethane 

and acetylene, and carbon black particles that are not captured 

by product separation bag filters.

Recommended emission prevention and control measures 

include the following: 

• Use primary feedstock with a sulfur content in the range of 

0.5 - 1.5 percent4;

• Preheat process air in heat exchangers using the hot 

gases (containing carbon black) leaving the furnace black 

reactor;

• Install and maintain high-performance bag filters to ensure 

high carbon black collection efficiency and minimum 

product losses of the residual carbon black in the filtered 

tail gas;

• Utilize the energy content of the tail gas (by burning the 

gas and using the energy produced);

• Primary NOX reduction techniques should be applied to 

reduce the NOX content in flue-gas originating from tail-gas 

combustion in energy producing systems 5;

• Install fabric filters for the air conveying system, vent 

collection system, and dryer purge gas6;

• Vent un-combusted tail-gas only during emergencies, startup and shut-down periods, and during periods of grade 

change.

Process Air Emissions – Coal Tar Distillation 

Although coal tar distillation emissions occur in normal operating 

conditions, the key emissions from these processes that warrant 

control are those consisting of tar fume, odor, polycyclic 

aromatic hydrocarbons (PAH), and particulate ma tter, which 

may originate from facility processes including delivering, 

storing, heating, mixing, and cooling tar. 

Recommended emission prevention and control measures 

include the fo llowing:

 

4 Specific emission levels of 10 – 50 kg SOX (as SO2) per tonne of rubber grade 

carbon black produced are possible, as a yearly average.

5 Plants emission levels associated with use of BAT are less than 0.6 g 

NOX/Nm3 as an hourly average at 3 % O2 during normal production. 

6 For the low temperature air conveying and vent collector systems, assoc iated 

emission levels are 10 to 30 mg/Nm3 as a half-hour average. For the dryer purge 

filter, associated emission levels are from less than 20 to 30 mg/Nm3 as a halfhour average
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 7

 

 WORLD BANK GROUP

• Use ground-based pumps and other methods to optimize 

tar deliveries to reduce emissions of tar fume and odor;

• Site storage tanks downwind of potential nearby receptors, 

control temperature of stored materials7, and implement 

careful handling procedures to prevent odor nuisance;

• Implement overfill prevention methods for bulk storage 

tanks, such as high-level alarms or volume indicators;

• Used local exhaust ventilation adequate to collect and treat 

VOC emissions from mixing tanks and other processing 

equipment.

Liquid Effluents

Liquid effluents include process and cooling water, storm water,

and other specific discharges (e.g. hydrotesting and cleaning,

mainly during facility start up and turnaround). 8 Process water 

discharges from LVIC manufacturing plants may include the 

acid wash from scheduled cleaning activities and purges, which 

are part of daily operation. Additional potential sources of 

effluents may include scrubbers, if used as air emission control 

systems. Accidental releases or leaks from product storage 

tanks such as refrigerated ammonia and acid storage may also 

produce effluents. Other sources include acidic and caustic 

effluents from the boiler feed water preparation for the different 

steam systems. Cooling water and storm water management 

are addressed in the General EHS Guidelines.

Effluents and control specific to different types of chemicals 

manufacturing plants are described below.

Effluents – Ammonia Manufacturing

Plant discharges, during normal operation, may occur due to 

process condensates or due to the scrubbing of waste gases 

containing ammonia and other products. In partial oxidation, 

 

7 The rate of fume emission doubles for approximately every 11oC rise in 

temperature.

8 Facility turnarounds are usually limited to once every three to four years and 

last a few weeks.

soot and ash removal may impact water discharged, if not 

properly handled.

Recommended measures to prevent, minimize, and control 

effluents from ammonia plants include:

• Recover ammonia absorbed from purge and flash gases in 

a closed loop system so that no aqueous ammonia 

emissions occur;

• Recover soot from gasification in partial oxidation 

processes and recycle the recovered material to the 

process.

Effluents – Acids Manufacturing

Effluents from nitric acid plants may be contaminated with 

nitrogen compounds. Effluents from hydrochloric acid plants 

can vary depending on manufacturing processes from traces of 

HCl when reacting H2 with Cl, to mineral salt (Na2SO4) when the 

acid is produced by reacting sodium chloride with sulfuric acid. 

Liquid releases from phosphoric acid plants mainly consist of 

the liquid effluents originating from vacuum cooler condensers 

and gas scrubbing systems used for condensation and cleaning 

of the vapors that evolve in the various process stages. These 

condensed acidic vapors contain mainly fluorine and small 

amounts of phosphoric acid. The fluorine released from the 

reactor and evaporators can be recovered as a commercial byproduct (fluorosilicic acid 20-25 percent).

Recommended measures to prevent, minimize, and control 

effluents from acid plants include:

• Use closed-loop reactors and evaporators to eliminate 

process wastewater;

• Recirculate the water used for the transport of 

phosphogypsum into the process after settling;
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 8

 

 WORLD BANK GROUP

• Treat scrubber effluent with lime or limestone or use 

seawater as a scrubbing liquid to precipitate fluorine as 

calcium fluoride;

• Install a separator to remove phosphoric acid droplets from 

vacuum flash coolers and vacuum evaporators emissions 

before scrubbing to minimize contamination of the scrubber 

effluent with phosphorous pentoxide (P2O5);

• Recover fluorosilicic acid (H2SiF6) from treatment of tail 

gases from hydrofluoric units for use as a feed material or 

for the manufacture of fluorides or silicofluorides. H2SiF6

can also be chemically combined to produce CaF2 and 

silica.

Effluents – Chlor-Alkali Plants

Brine is one of key waste streams of the chlor-alkali industry. 

Membrane cells may use recycled brine requiring 

dechlorination. Specifically for membrane technology, brine 

purification is of critical importance to long membrane life and 

high efficiency. The main components in brine purification 

wastes are sulfate, chloride, free oxidants, chlorate, bromate,

and carbon tetrachloride.

The main sources of liquid effluent from the soda ash process 

are typically waste water from the distillation and brine 

purification and cooling waters. The effluents are characterized 

by high levels of suspended solids 9. Another significant issue is 

the potential discharge of heavy metals present in the main raw 

materials10.

Recommended measures to prevent, minimize, and control 

effluents from chlor-alkali plants include:

 

9 Loads of suspended solids discharged with waste waters are generally 

significant and range from 90 to 700 kg/t soda ash, with an average value 

estimated at 240 kg/t soda ash.

10 For a soda ash plant with a capacity of around 600 kt/year, 10 tonnes per 

year can be reached.

• Purify brine by pH adjustment, precipitation, flocculation 

and filtration to keep impurities at acceptable levels. The 

consumption of chemicals which are employed to purify the 

brine varies from plant to plant depending on the impurities 

of the brine;

• Recycle brine in membrane technology, removing 

impurities by ion exchange resin units. Regeneration of 

resins requires caustic soda and acid washing;

• Minimize consumption and discharge of sulfuric acid by 

means of on-site re-concentration in closed loop 

evaporators. The spent acid should be used to control pH 

in process and waste water streams; resold to a user that 

accepts this quality of acid; or returned to a sulfuric acid 

manufa cturer for re-concentration;

• Use fixed bed catalytic reduction, chemical reduction, or 

other equally effective method to minimize discharge of 

free oxidants 11;

• Adopt carbon tetrachloride-free chlorine liquefaction and 

purification processes;

• Use acid conditions in the anolyte (pH 1-2) to minimize the 

formation of chlorate (ClO3) and bromate (BrO3), and 

chlorate destruction in the brine circuit to remove chlorate 

before purging in membrane plants 12. 

Effluents – Carbon Black / Coal Tar Distillation

Wastewater effluents are of relatively limited significance for the 

carbon black industry and in coal tar distillation units.

A zero discharge to water is possible for some types of carbon 

black plants. However, the production of some rubber black and 

nearly all specialty black grades require clean quench water. 

Suspended solids (mainly carbon black) should be filtered 

 

11 The emission level of free oxidants to water associated with implementation 

of best available technuiques is less than 10 mg/l.

12 The chlorate level associated with best available techniques in the brine 

circuit is 1-5 g/l and the associated bromate level is 2-10 mg/l, and depends on 

the bromide level in the salt.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 9

 

 WORLD BANK GROUP

before discharge (or re-use) to levels less than 20 mg/l. After 

filtration, process streams can be reused.

Suspended solids, BOD and PAH concentrations should be 

monitored in effluents from coal tar distillation units.

Hydrostatic Testing Water

Hydrostatic testing of equipment and pipelines usually needs

significant amount of water (e.g., NH3 tanks may have 

capacities of more than 20-30,000 m3). Chemical additives 

(typically a corrosion inhibitor, an oxygen scavenger, and a dye) 

are often added to the water to prevent internal corrosion. 

In managing hydrotest waters, pollution prevention and control 

measures should be considered including: optimizing water 

consumption and optimum dosage and careful selection of 

needed chemicals.

If discharge of hydrotest waters to the sea or to surface water is 

the only feasible alternative, a hydrotest water disposal plan 

should be prepared. The plan should include, at a minimum, 

characteristics of the discharge point(s) rate of discharge, 

chemical use and dispersion, environmental risk, and required 

monitoring. 

Hydrotest water disposal into shallow coastal waters should be 

avoided.

Wastes

Well-managed chemicals manufacturing plants should not 

generate significant quantities of solid wastes during normal 

operation. Typical wastes generated include waste oils, spent 

catalysts, sludge from wastewater treatment units, collected 

dust from bag houses, bottom ashes from boilers, muds and 

cakes from filtration units, etc.

Recommended management strategies for spent catalysts 

include the following:

• Proper on-site management, including submerging 

pyrophoric spent catalysts in water during temporary 

storage and transport until they reach the final point of 

treatment to avoid uncontrolled exothermic reactions;

• Off-site management by specialized companies that can 

recover and reclycle heavy metals (or precious metals from 

nitric acid plant catalysts) whenever possible.

Storage and handling of hazardous and non-hazardous wastes 

should be conducted in a way consistent with good EHS 

practice for waste management, as described in the EHS 

General Guidelines.

Waste – Ammonia Manufacturing

Ammonia manufacturing processes should not produce

significant solid wastes 13. Spent catalysts and molecular sieves 

management should be conducted as specified above. 

Waste – Acids Manufacturing

Phosphogypsum is the most significant by-product in wet 

phosphoric acid production14. Phosphogypsum contains a wide 

range of impurities, some of which are considered a potential 

hazard to the environment and public health.

15,16

 

13 Spent catalysts and other solid waste should be less than 0.2kg per ton of 

product.

14 Around 4 - 5 tons of phosphogypsum (princ ipally calcium sulfate, CaSO4) are 

produced for every ton of phosphoric acid produced

15 The impurities contained in the phosphate rock are distributed between the 

phosphoric acid produced and the calcium sulfate (gypsum); mercury, lead and 

radioactive components, where present, end up mainly in the gy psum, while 

arsenic and the other heavy metals such as cadmium end up mainly in the acid. 

The radioactivity of phosphate rock is mainly from radionuclides from the 

radioactive decay series of uranium-238.

16 Phosphate rock, phosphogypsum, and the effluents produced from a 

phosphoric acid plant have generally a lower radioactivity than the exemption 

values given in the relevant international regulations and guidelines (for 

example, EU Directive 96/26/EURATOM)
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 10

 

 WORLD BANK GROUP

Calcium sulfate (anhydrite) is produced as a by-product of 

hydrofluoric acid (HF) manufacturing, containing between 0.2 to 

2.0 % of unreacted CaF2 and less than 1.0 % H2SO4. It also 

contains the majority of the trace impurities contained in the 

fluorspar 17. 

Recommended measures to prevent or minimize solid waste 

generation and to manage solid waste from acid plants include:

• Disposal of phosphogypsum in land facilities designed to 

prevent leaching to groundwater or surface water. Any 

effort should be made in order to reduce the impact of 

phosphogypsum disposal and possibly improve the quality

of the gypsum, for its reuse. Disposal to sea is considered 

non acceptable;

• Refinement and sale of calcium sulfate anhydrite from HF 

production for use in other products (e.g. cement), if 

possible.

Waste – Chlor-Alkali Plants

Brine sludges are one of the largest waste streams of the chloralkali industry. The quantity of brine filtration sludges mainly 

depends on the incoming salt characteristics, used for the 

purification of the brine. The precipitated salts are removed from 

the brine through decantation/clarification and filtration. The 

sludge may be removed discontinuously by flushing with a weak 

hydrochloric acid solution. The acid causes the precipitate to 

dissolve and the relatively harmless solution can be discharged 

with liquid effluent. Wastes are generated during the secondary 

brine purification and consist of used materials such as precoat 

and body feed material made of cellulose. The precoat filter 

sludge from the brine softener consists mainly of alphacellulose, contaminated with iron hydroxide and silica18. Ion 

 

17 About 3.7 tonnes of anhydrite per tonne of HF are produced as by -product.

18 Membrane cell plants report a figure of 600 g/t for sludge from brine 

softening.

exchange resins for secondary brine purification are rarely 

changed19. Spent membranes 20 and gaskets from membrane 

cells are other waste streams. 

The main solid wastes from soda ash unit are fines of limestone 

(30 – 300 kg/t soda ash) and non recycled grits at slaker (10 –

120 kg/t soda ash). 

Recommended measures to prevent, minimize solid waste 

generation and to manage solid waste from chlor-alkali plants 

include:

• Attempt to find reuse options for waste solids from the 

purification of salt brine; if the waste must be disposed of, 

consider the use of natural repositories, such brine cavities;

• Select limestone with high CaCO3 content, appropriate 

physical characteristics, and limited content of heavy 

metals and other impurities.

Waste – Carbon Black / Coal Tar Distillation

Carbon black processes generate very limited amount of 

hazardous waste (oil residues). Coal-tar pitch is a black solid 

residue from the distillation of coal tar. The recovery of tar 

chemicals leaves residual oils, including heavy naphtha, 

dephenolated carbolic oil, naphthalene drained oil, wash oil, 

strained anthracene oil, and heavy oil.

Recommended measures to prevent, minimize solid waste 

generation and to manage solid waste include:

• Reuse spent oil, oil sludge, and coal tar distillation residues 

as feedstock or fuel, if possible;

• Recycle off-specification carbon black back into the 

process.

 

19 Resins are regenerated about 30 times per year.

20 The membranes have a lifetime of between 2 and 4 years.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 11

 

 WORLD BANK GROUP

Hazardous Materials Management

Chemical manufacturing plants are required to assess the risks 

associated with the use and handling of hazardous materials

and implement practices to prevent and minimized such risks. 

As indicated in the General EHS Guidelines, the application of 

these management practices should be documented in a written 

Hazardous Materials Management Plan21. The purpose of this 

plan is to establish and implement a systema tic set of preventive 

actions against accidental releases of substances that can 

cause serious harm to the public and the environment from 

short-term exposures and to mitigate the severity of releases

that do occur.

Industry-specific pollution prevention and control practices 

include the following:

• Accidental releases of fluids through should be prevented 

trough inspections and maintenance of storage and 

conveyance systems, including stuffing boxes on pumps 

and valves and other potential leakage points. Spillages of 

dangerous intermediates and product should be contained 

and recovered or neutralized as quick as possible;

• Secondary containment for the storage tanks storing liquids 

(i.e, ammonia, acids, etc.) and spare capacity for 

dangerous products like chlorine should be installed as 

discussed in the General EHS Guidelines;

• Maintain good housekeeping practices, including 

conducting product transfer activities over paved areas and 

prompt collection of small spills.

Noise

In chemical manufacturing facilities, significant noise sources 

include large size rotating machines, such as compressors and 

turbines, pumps, electric motors, air coolers, and fired heaters. 

 

21 See IFC Hazardous Waste Management Manual.

During emergency depressurization, high noise levels can be 

generated due to high pressure gases to flare and/or steam 

release into the atmosphere.

Noise prevention and abatement strategies include:

• Optimization of plant layouts in order to use the larger 

buildings as noise barriers and locating noise sources as 

far as possible from existing receptors;

• Use of low noise generation equipment;

• Installation of acoustic insulating barriers and silencers.

Noise abatement and control measures are similar to other large 

industries and are addressed in the General EHS Guidelines.

Odors

Odors from fugitive vapor releases or from wastewater 

treatment plants may be generated in the LVIC manufacturing 

processes. Adequate controls to eliminate leaks should be 

implemented to minimize fugitive releases and prevent odor 

nuisances. 

Decommissioning

Chemical manufacturing facilities may have important quantities 

of solid and liquid hazardous materials such as CO2 removal 

solutions, liquid ammonia, chlorine, soda, acids and products in 

process and storage systems, off spec products, spent 

catalysts, and mercury from mercury cell chlor-alkali plants. 

Recommended management practices of decommissioning 

activities include the following: 

• In the case of mercury cell chlor-alkali plants, carefully plan 

all decommissioning steps to minimize releases of mercury 

and other hazardous substances (including dioxins and 

furans if graphite anodes were used) and to protect worker 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 12

 

 WORLD BANK GROUP

health and safety, and plan for disposition of the remaining 

mercury;

• Collect CO2 removal solutions in the ammonia plants and 

all dangerous products for further handling and disposal as 

a hazardous waste material;

• Remove spent catalysts from NH3 and HNO3 plants for 

further management as described in the solid waste 

section above;

• Recover and further manage NH3, Cl2, acids, and all other 

products from the synthesis section and storage tanks as 

well as all products and intermediates from the storage 

tanks according to hazardous materials management 

guidance from the General EHS Guidelines.

General guidance on decommissioning and contaminated land 

remediation is provided in the General EHS Guidelines.

1.2 Occupational Health and Safety

The occupational health and safety issues that may occur during 

the construction and decommissioning of LVIC facilities are 

similar to those of other industrial facilities, and their 

management is discussed in the General EHS Guidelines. 

Facility -specific occupational health and safety issues should be 

identified based on job safety analysis or comprehensive hazard 

or risk assessment, using established methodologies such as a 

hazard identification study [HAZID], hazard and operability study 

[HAZOP], or a quantitative risk assessment [QRA]. As a general 

approach, health and safety management planning should 

include the adoption of a systematic and structured approach for 

prevention and control of physical, chemical, biological, and 

radiological health and safety hazards described in the General 

EHS Guidelines.

In addition, occupational health and safety issues for specific 

consideration in chemical operations include:

• Chemical hazards due to acute and chronic exposure to 

toxic gases and other hazardous compounds;

• Major hazards, including fires and explosions.

Major hazards should be managed according to international 

regulations and best practices (e.g., OECD 

Recommendations 22, EU Seveso II Directive23 and USA EPA 

Risk Management Program Rule24).

Chemical Hazards

The industry is characterized by the presence of toxic 

compounds, including chlorine gas, ammonia, acids, caustic 

soda, amines, components of coal tar (e.g. mononuclear and 

polycyclic aromatic hydrocarbons, phenols, and pyridine bases), 

which can be toxic when ingested, inhaled, or absorbed through 

the skin. The main health hazard usually associated with coal 

tar and its products is carcinogenicity due to long-term, 

continued exposure of the skin to finely divided solid pitch 

(dust). 

Recommendations to prevent, minimize, or control occupational 

health impacts from exposure to toxic substances at these

facilities include:

• Assess and minimize the concentrations of toxic 

substances in working areas in both normal and 

emergency conditions. Rigorous workplace monitoring 

protocols ought to be in place as part of the overall 

occupational and health and safety management system. 

Protective clothing, including eye protection and PVC 

gloves, should be worn, suitable respirators be available, 

and regular medical checkups be carried out on all 

personnel, as needed;

 

22 OECD, Guiding Principles for Chemical Accident Prevention, Preparedness

and Response, Second Edition (2003).

23 EU Council Directive 96/82/EC, so-called Seveso II Directive, extended by the 

Directive 2003/105/EC.

24 EPA, 40 CFR Part 68, 1996 - Chemical accident prevention provisions .
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 13

 

 WORLD BANK GROUP

• Install gas detectors in hazard areas, wherever possible. 

For example, chlorine detectors should be placed in areas 

of potential risk of chlorine leaks, giving immediate 

indication of the presence and location of any leakage;

• Ensure effective ventilation, where the lower boiling 

products are handled;

• Provide and use barrier creams formulated against 

aromatic hydrocarbons. 

Major Hazards

The most significant safety impacts are related to the handling 

and storage of NH3 (volatile and poisonous in high 

concentrations), chlorine (highly poisonous), caustic soda, nitric, 

hydrochloric, sulfuric, hydrofluoric, phosphoric acids and organic 

compounds and combustible gases such as natural gas, CO, 

and H2 and other process chemicals. These impacts may 

include significant acute exposures to workers and, potentially, 

to surrounding communities, depending on the quantities and 

types of accidentally released chemicals and the conditions for 

reactive or catastrophic events, such as fire and explosion. 

LVIC manufacturing facilities may generate or process large 

quantities of combustible gases, such as natural gas, H2, CO, 

and other process chemicals. Synthetic Gas (SynGas; 

containing H2 and CO25) generated at ammonia plants may 

cause “Jet Fires” if ignited in the release section, or give rise to 

Vapor Cloud Explosion, “Fireballs,” or “Flash Fires,” depending 

on the quantity of flammable material involved, the degree of 

confinement of the cloud, and the congestion of the area 

interested by the flammable cloud. 

The risk of fire, explosion and other major hazards should be 

minimized through the following measures:

 

25 Hydrogen and carbon monoxide have autoignition temperatures of 500°C 

and 609°C, respectively; therefore in some points of the SynGas generation 

unit, where gas temperature is higher, potential gas releases may self ignite 

without the need of ignition sources.

• Establishing a plant layout to reduce the frequency of 

product transfers and the likelihood of accidental releases, 

as well as to facilitate the collection of accidental releases;

• Early detection of the release;

• Limiting the inventory which may be released by isolation 

of the installation from large inventories and isolation and 

blow-down of pressurized flammable gases inventories. 

Process areas, storage areas, utility areas, and safe areas 

should be segregated, preferably by adoption of safety 

distances. These distances can be derived from safety 

analyses specific for the facility, considering the occurrence 

of the hazards or from applicable standards or guidelines 

(e.g., API, NFPA);

• Removing potential ignition sources;

• Removing or diluting the release and limiting the area 

affected by the loss of containment.

Recommended industry specific measures to minimize the 

above mentioned risks include:

• Minimize the liquid chlorine inventory and the length of 

pipeline containing liquid chlorine;

• Design atmospheric ammonia storage tanks (- 33°C) with 

dual walls and an external concrete wall with the roof 

resting on the outer wall, and using an adequate margin 

between operating and relief pressure. Refrigerated 

storage should be preferred for storage of large quantities 

of liquid ammonia, since the initial release of ammonia in 

the case of a line or tank failure is slower than with 

pressurized ammonia storage systems;

• Design chlorine storage tanks based on a specific analysis 

of major failure or accident risks and consequences, and 

accounting on the possibility to safely recover and handle 

any product spills—consider low-temperature storage (-

34°C) for large storage capacities, and provision of at least 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 14

 

 WORLD BANK GROUP

one empty tank equal in capacity to the largest chlorine 

storage tank as an emergency spare; 

• Given their highly corrosive and toxic nature, special 

attention should be given to the handling and storage of 

acids including prevention of leaks or spills to effluent 

waters by provision of secondary containment; separation 

from critical drainage channels; and continuous monitoring 

and alarm detection systems (such as automatic pH 

monitoring) of at-risk containment and drainage networks; 

• Avoid pressurizing for unloading large quantities of nitric 

acid. The recommended material for tanks, vessels and 

accessories is low carbon austenitic stainless steel;

• Only use specially trained and certified staff or contractors 

for deliveries and transfer of all process chemicals, 

including chemicals used in the CO2 removal unit of the 

ammonia plant. 

1.3 Community Health and Safety

Community health and safety impacts during the construction 

are common to those of most industrial facilities, and are 

discussed in the General EHS Guideline. These impacts 

include, among other things, dust, noise, and vibration from 

construction vehicle transit, and communicable disease 

associated with the influx of temporary construction labor. 

The most significant community health and safety hazards 

during the operation of chemical facilities are related to:

• Handling and storage of hazardous materials including raw 

materials, intermediaries, products and wastes near 

populated areas;

• Shipping of hazardous products (ammonia, chlorine, acids, 

carbon black), with possibility of accidental leak of toxic 

and flammable gases;

• Disposal of solid waste (phosphogypsum, sludge).

The design should include safeguards to minimize and control 

hazards to the community, through the following:

• Identifying reasonable design leak cases;

• Assessing the effects of the potential leaks on the 

surrounding areas, including groundwater and soil 

pollution; 

• Properly selecting the plant location in respect to the 

inhabited areas, meteorological conditions (e.g. prevailing 

wind directions), and water resources (e.g., groundwater 

vulnerability) and identifying safe distances between the 

plant area and the community areas; and

• Identifying the prevention and mitigation measures required 

to avoid or minimize the hazards.

If the facilities are located on the shore, the ship traffic 

associated with the facilities should be considered in the 

assessment, analyzing the potential impact of the traffic on the 

local marine traffic and activities and the potential impacts of 

liquids leaks from the unloading or offloading operations. 

Measures to avoid accidental impacts and minimize disturbance 

to other marine activities in the area should be assessed. Risk 

analysis and emergency planning should include, at a minimum, 

the preparation of an Emergency Management Plan, prepared 

with the participation of local authorities and potentially affected 

communities. Other community health and safety hazards are 

common to those of most large industrial facilities, and are 

discussed in the General EHS Guideline. 

Community health and safety impacts during the 

decommissioning are common to those of most large industrial 

facilities, and are discussed in the General EHS Guideline. 

These impacts include, among other things, transport safety, 

disposal of demolition waste that may include hazardous 

materials, and other impacts related to physical conditions and 

the presence of hazardous materials after site abandonment. 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 15

 

 WORLD BANK GROUP

Guidance for the management of these issues at chemical

plants is presented under Section 1.2 and in relevant sections of 

the General EHS Guidelines including “Planning, Siting, and 

Design”, and “Emergency Preparedness and Response”.

2.0 Performance Indicators and 

Monitoring

2.1 Environment

Emissions and Effluent Guidelines

Tables 1 and 2 present emission and effluent guidelines for this 

sector. Guideline values for process emissions and effluents in 

this sector are indicative of good international industry practice 

as reflected in relevant standards of countries with recognized 

regulatory frameworks. These levels should be achieved, 

without dilution, at least 95 percent of the time that the plant or 

unit is operating, to be calculated as a proportion of annual 

operating hours. Deviation from these levels in consideration of 

specific, local project conditions should be justified in the 

environmental assessment. 

Effluent guidelines are applicable for direct discharges of treated 

effluents to surface waters for general use. Site-specific 

discharge levels may be established based on the availability 

and conditions in the use of publicly operated sewage collection 

and treatment systems or, if discharged directly to surface 

waters, on the receiving water use classification as described in 

the General EHS Guideline. 

Emissions guidelines are applicable to process emissions. 

Combustion source emissions guidelines associated with steam 

and power generation activities from sources with a capacity 

equal to or lower than 50 thermal megawatts are addressed in 

the General EHS Guideline with larger power source emissions 

addressed in the EHS Guidelines for Thermal Power. 

Guidance on ambient considerations based on the total load of

emissions is provided in the General EHS Guideline.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 16

 

 WORLD BANK GROUP

Table 1. Air Emissions Levels

Pollutant Units Guideline Value

Ammonia Plants

NH3 mg/Nm3 50

NOX mg/Nm3 300

Particulate Matter mg/Nm3 50

Nitric Acid Plants

NOX mg/Nm3 300

N2O mg/Nm3 800

NH3 mg/Nm3 10

Sulfuric Acid Plants

SO2 mg/Nm3

450

(2 kg/t acid)

SO3 mg/Nm3

60

(0.075 kg/t acid)

H2S mg/Nm3 5

NOX mg/Nm3 200

Phosphoric / Hydrofluoric Acids Plants

Fluorides (gas eous) as HF mg/Nm3 5

Particulate Matter/CaF2 mg/Nm3

50

(0.10 kg/t phosphate 

rock)

Chlor-alkali / Hydrochloric Acid Plants

Cl2 mg/Nm3

1 (partial liquefaction)

3 (complete liquefaction

HCl ppmv 20

Hg mg/Nm3

0.2

(annual average 

emission of 1 g/t 

chlorine)

Soda Ash Plants

NH3 mg/Nm3 50

H2S mg/Nm3 5

NOx mg/Nm3 200

Particulate Matter mg/Nm3 50

Carbon Black

SO2 mg/Nm3 850

NOX mg/Nm3 600

CO mg/Nm3 500

Particulate Matter mg/Nm3 30

VOC mg/Nm3 50

Coal Tar Distillation

Tar fume mg/Nm3 10

VOC mg/Nm3 50

Particulate Matter mg/Nm3 50

Table 2. Effluent Levels

Pollutant Units Guideline Value

pH S.U. 6-9

Temperature Increase °C <3

Ammonia Plants

NH3 mg/l 10

(0.1 kg/t) 1

TSS mg/l 30

Nitric Acid Plants

NH3 mg/l 10

Nitrates g/t 25

TSS mg/l 30

Sulfuric Acid Plants

Phosphorus mg/l 5

Fluoride mg/l 20

TSS mg/l 30

Phosphoric Acid Plants

Phosphorus mg/l 5

Fluoride mg/l 20

TSS mg/l 30

Hydrofluoric Acid Plants

Fluorides kg/tonne 

HF 1

kg/tonne 

HF 1Suspended Solids

mg/l 30

Chlor-alkali /Hydrochloric Acid Plant

TSS mg/l 202

COD mg/l 1502

AOX mg/l 0.52

Sulfides mg/l 1

Chlorine mg/l 0.22

Mercury --

0.05 mg/l

0.1 g/t chlorine

Toxicity to Fish Eggs TF 2

Soda Ash Plants

Suspended solids kg/t 270

Phosphorus kg/t 0.2

TSS mg/l 30

Ammonia (as N) mg/l 10

Carbon Black Plants

COD mg/l 100

Suspended Solids mg/l 20

Coal Tar Distillation Plants

BOD5 mg/l 35 (monthly average)

90 (daily max imum)

TSS mg/l 50 (monthly average)

160 (daily max imum)

Anthracene, Naphthalene and 

Phenanthrene (each) μg/l 20 (monthly average)60 (daily max imum)

Notes: 

1. Load based guideline: 0.1 kg/t of product

2. Non-asbestos diaphragm plants
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 17

 

 WORLD BANK GROUP

Resource Use, Energy Consumption, Emission

and Waste Generation

Tables 3 and 4 provide examples of resource consumption and 

waste generation benchmarks in this sector. Industry 

benchmark values are provided for comparative purposes only 

and individual projects should target continual improvement in 

these areas.

Table 3. Resource and Energy Consumption

Product Unit Industry Benchmark

Ammonia GJ lower heating value 

(LHV)/tonne NH3

28.8 to 31.5(1)

Tonne phosphate rock/tonne

P2O5

2.6-3.5 (1)

KWh/tonne P2O5 120-180 (1)

Phosphoric 

Acid

m3 cooling water/tonne P2O5 100-150 (1)

Tonne CaF2l/tonne HF 2.1-2.2 (4)

Tonne H2SO4/tonne HF 2.6-2.7 (4)

Hydrofluoric 

Acid

KWh/tonne HF 150-300 (4)

KWh/tonne Cl2 3000 without Cl 

liquefaction

3200 with Cl liquefaction 

/ evaporation(3)

Tonne NaCl/tonne Cl2 1.750 (3)

Chlor-Alkali

g Hg/tonne of chlorine capacity

(mercury cell plants)

0.2-0.5 (3)

GJ/tonne soda ash 9.7-13.6 (2)

Tonne limestone/tonne soda

ash

1.09-1.82 (2)

Tonne NaCl/tonne soda ash 1.53-1.80 (2)

Soda Ash

m3 cooling water/tonne soda

ash

50-100 (2)

KWh/tonne carbon black 430-550 (2) Carbon Black

GJ/tonne carbon black 1.55-2 (2)

Notes:

1. European Fertilizer Manufacturers Association (EFMA). 2000.

2. EU IPPC - Reference Document on Best Available Techniques in Large 

Volume Inorganic Chemicals - Solid and Others industry. December 2006.

3. EU IPPC - Reference Document on Best Available Techniques in the 

Chlor-Alkali Manufacturing industry December 2001.

4. EU IPPC - Reference Document on Best Available Techniques in Large 

Volume Inorganic Chemicals – Ammonia, Acids and Fertilizers Industries. 

October 2006.

Table 4. Emissions, Effluents and Waste 

Generation

Parameter Unit Industry 

Benchmark

Ammonia Plants

CO2 from process tonne/tonne NH3 1.15-1.3 (1)

NOX (advanced conventional 

reforming processes and 

processes with reduced primary 

reforming)

kg/tonne NH3 0.29 – 0.32

NOX (heat exchange autothermal 

reforming)

kg/tonne NH3 0.175

Nitric Acid Plants

N2O kg/tonne 100% 

HNO3

0.15-0.6 (4)

NOX ppmv 5-75 (4)

Sulfuric Acid Plants

SO2 (Sulfur burning, double 

contact/double absorption)

mg/Nm3 30-350 (1)(4)

SO2 (Single contact/single 

absorption)

mg/Nm3 100-450(4)

Phosphoric / Hydrofluoric Acid Plants

Fluorides mg/Nm3 0.6-5

(4)

SO2 kg/tonne HF 0.001 – 0.01(4)

Solid Waste (phosphogypsum) tonne/tonne P2O5 4-5 (1)

Anhydrite (CaSO4) tonne/tonne HF 3.7 (4)

Chlor Alkali Plants

Cl2 (partial liquefaction) mg/Nm3 <1 (3)

Cl2 (total liquefaction) mg/Nm3 <3 (3)

Chlorates (brine circuit) g/l 1-5 (3)

Bromates (brine circuit) mg/l 2-10 (3)

Soda Ash Plants

CO2 Kg/tonne soda ash 200-400 (2)

Cl Kg/tonne soda ash 850-1100 (2)
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 18

 

 WORLD BANK GROUP

Ca Kg/tonne soda ash 340-400 (2)

Na Kg/tonne soda ash 160-220 (2)

Waste water/suspended solids m3/tonne/ tonne 

soda ash

8.5-10.7/ 0.09-

024 (2)

Carbon Black Plants

SO2

kg/tonne of rubber 

grade carbon black 10-50(2)

NOX mg/Nm3 <600(2)

VOC mg/Nm3 <50(2)

Table 4 Notes:

1. European Fertilizer Manufacturers Association (EFMA). 2000; 

2. EU IPPC - Reference Document on Best Available Techniques in Large 

Volume Inorganic Chemicals - Solid and Other Industries. Dec, 2006.; 

3. EC IPPC - Reference Document on Best Available Techniques in the 

Chlor-Alkali Manufacturing industry December 2001; 

4. EC IPPC - Referenc e Document on Best Available Techniques in Large 

Volume Inorganic Chemicals – Ammonia, Acids and Fertilizers 

Industries. Oct, 2006.

Environmental Monitoring

Environmental monitoring programs for this sector should be 

implemented to address all activities that have been identified to 

have potentially significant impacts on the environment, during 

normal operations and upset conditions. Environmental 

monitoring activities should be based on direct or indirect 

indicators of emissions, effluents, and resource use applicable 

to the particular project. 

Monitoring frequency should be sufficient to provide 

representative data for the parameter being monitored. 

Monitoring should be conducted by trained individuals following 

monitoring and record-keeping procedures and using properly 

calibrated and maintained equipment. Monitoring data should be 

analyzed and reviewed at regular intervals and compared with 

the operating standards so that any necessary corrective 

actions can be taken. Additional guidance on applicable 

sampling and analytical methods for emi ssions and effluents is 

provided in the General EHS Guidelines.

2.2 Occupational Health and Safety 

Performance

Occupational Health and Safety Guidelines

Occupational health and safety performance should be 

evaluated against internationally published exposure guidelines, 

of which examples include the Threshold Limit Value (TLV®) 

occupational exposure guidelines and Biological Exposure 

Indices (BEIs®) published by American Conference of 

Governmental Industrial Hygienists (ACGIH), 26 the United 

States National Institute for Occupational Health and Safety 

(NIOSH),27 Permissible Exposure Limits (PELs) published by 

the Occupational Safety and Health Administration of the 

United States (OSHA), 28 Indicative Occupational Exposure Limit 

Values published by European Union member states, 29 or other 

similar sources. 

Accident and Fatality Rates

Projects should try to reduce the number of accidents among 

project workers (whether directly employed or subcontracted) to 

a rate of zero, especially accidents that could result in lost work 

time, different levels of disability, or even fatalities. Facility rates 

may be benchmarked against the performance of facilities in this 

sector in developed countries through consultation with 

published sources (e.g. US Bureau of Labor Statistics and UK 

Health and Safety Executive)30.

Occupational Health and Safety Monitoring

The working environment should be monitored for occupational 

hazards relevant to the specific project. Monitoring should be 

 

26 Available at: http://www.acgih.org/TLV/

27 Available at: http://www.cdc.gov/niosh/npg/

28 Available at: 

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDAR

DS&p_id=9992

29 Available at: http://europe.osha.eu.int/good_practice/risks/ds/oel/

30 Available at: http://www.bls.gov/iif/ and 

http://www.hse.gov.uk/statistics/index.htm 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 19

 

 WORLD BANK GROUP

designed and implemented by accredited professionals 31 as part 

of an occupational health and safety monitoring program. 

Facilities should also maintain a record of occupational 

accidents and diseases and dangerous occurrences and 

accidents. Additional guidance on occupational health and 

safety monitoring programs is provided in the General EHS 

Guidelines.

 

31 Accredited professionals may include Certified Industrial Hygienists, 

Registered Occupational Hygienists, or Certified Safety Professionals or their 

equiv alent. 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION 

 

DECEMBER 10, 2007 20

 

 WORLD BANK GROUP

3.0 References

Australian Government, Department of the Environment and Heritage. 2004. 

Emission Estimation Technique Manual for Inorganic Chemicals Manufacturing. 

Version 2.0. Canberra, Australia

European Integrated Pollution Prevention and Control Bureau (EIPPCB). 2001. 

Integrated Pollution Prevention and Control (IPPC ) Reference Document on 

Best Available Techniques in the Chlor-Alkali Manufacturing Industry. December 

2001. Sevilla, Spain

EIPPCB. 2006a. Integrated Pollution Prevention and Control (IPPC) Reference 

Document on Best Available Techniques in Large Volume Inorganic Chemicals -

Solids and Others Industry. October 2006. Sevilla, Spain

EIPPCB. 2006b. Integrated Pollution Prevention and Control (IPPC) Reference 

Document on Best Available Techniques in Large Volume Inorganic Chemicals 

– Ammonia, Acids and Fertilisers. December 2006. Sevilla, Spain

European Fertilizer Manufacturers Association (EFMA). 2000a. Best Available 

Techniques for Pollution Prevention and Control in the European Fertilizer 

Industry. “Production of Ammonia,” Booklet No. 1. Brussels, Belgium

EFMA. 2000b. Best Available Techniques for Pollution Prevention and Control in 

the European Fertilizer Industry. “Production of Nitric Acid,” Booklet No. 2. 

Brussels, Belgium

EFMA. 2000c. Best Available Techniques for Pollution Prevention and Control in 

the European Fertilizer Industry. “Production of Sulphuric Acid,” Booklet No. 3. 

Brussels, Belgium

EFMA. 2000d. Best Available Techniques for Pollution Prevention and Control in 

the European Fertilizer Industry. “Production of Phosphoric Acid,” Booklet No. 4. 

Brussels, Belgium

German Federal Government. 2002. First General Administrative Regulation 

Pertaining the Federal Immission Control Act (Technical Instructions on Air 

Quality Control – TA Luft). Berlin, Germany

German Federal Ministry for the Environment, Nature Conservation and Nuclear 

Safety. 2004. Promulgation of the New Version of the Ordinance on 

Requirements for the Discharge of Waste Water into Waters (Waste Water 

Ordinance - AbwV) of 17. June 2004. Berlin, Germany

Helsinki Commission. 2002. Helcom Recommendation 23/6. Reduction of 

Emissions and Discharges of Mercury from Chloralkali Industry. Helsinki, 

Finland.

Intergovernmental Panel on Climate Change (IPCC). 2006. Special Report, 

Carbon Dioxide Capture and Storage, March 2006. Geneva, Switzerland

Kirk-Othmer, R.E. 2006. Encyclopedia of Chemical Technology. 5th Edition. John 

Wiley and Sons Ltd., New York, NY

National Fire Protection Association (NFPA). 2000. Standard 850: 

Recommended Practice for Fire Protection for Electric Generating Plants and 

High Voltage Direct Current Converter Stations. 2000 Edition. Quincy, 

Massachusetts

NFPA. 2004. Standard 120: Standard for Fire Prevention and Control in Coal 

Mines . 2004 Edition. Quincy, Massachusetts

Paris Commission. 1990. Parcom Decision 90/3 of 14 June 1990 on Reducing 

Atmospheric Emissions from Existing Chlor-Alkali Plants. Paris, France

UK Environmental Agency. 1999a. IPC Guidance Note Series 2 (S2) Chemical 

Industry Sector. S2 4.03: Inorganic Acids and Halogens. Bristol, UK

UK Environmental Agency. 1999b. IPC Guidance Note Series 2 (S2) Chemical 

Industry Sector. S2 4.04: Inorganic Chemicals. Bristol, UK

UK Environmental Agency. 2004a. Sector Guidance Note IPPC S4.03. 

Guidance for the Inorganic Chemicals Sector. Bristol, UK

UK Environmental Agency. 2004b. Process Guidance Note 6/42 (04). Secretary 

of State's Guidance for Bitumen and Tar Processes . Bristol, UK

US Environmental Protection Agency (EPA). Office of Compliance. 1995. Sector 

Notebook Project. Profile of the Inorganic Chemical Industry. Was hington, DC

US EPA. 40 CFR Part 60, Standards of Performance for New and Existing 

Stationary Sources: Subpart G—Standards of Performance for Nitric Acid 

Plants. Washington, DC. Available at http://www.gpoaccess.gov/cfr/index.html

(accessed on October 2006)

US EPA. 40 CFR Part 60, Standards of Performance for New and Existing 

Stationary Sources: Subpart H—Standards of Performance for Sulfuric Acid 

Plants. Washington, DC. Available at http://www.gpoaccess.gov/cfr/index.html

(accessed on October 2006)

US EPA. 40 CFR Part 60, Standards of Performance for New and Existing 

Stationary Sources: Subpart T—Standards of Performance for the Phosphate 

Fertilizer Industry: Wet-Process Phosphoric Acid Plants. Washington, DC. 

Available at http://www.gpoaccess.gov/cfr/index.html (accessed on October 

2006)

US EPA. 40 CFR Part 63, National Emission Standards for Hazardous Air 

Pollutants for Source Categories: Subpart AA—National Emission Standards for 

Hazardous Air Pollutants From Phosphoric Acid Manufacturing Plants. 

Washington, DC. Available at http://www.gpoaccess.gov/cfr/index.html

(accessed on October 2006)

US EPA. 40 CFR Part 63, National Emission Standards for Hazardous Air 

Pollutants for Source Categories: Subpart IIIII—National Emission Standards for 

Hazardous Air Pollutants: Mercury Emissions From Mercury Cell Chlor-Alkali 

Plants. Washington, DC. Available at http://www.gpoaccess.gov/cfr/index.html

(accessed on October 2006)

US EPA. 40 CFR Part 63, National Emission Standards for Hazardous Air 

Pollutants for Source Categories: Subpart NNNNN—National Emission 

Standards for Hazardous Air Pollutants: Hydrochloric Acid Production. 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 21

 

 WORLD BANK GROUP

Washington, DC. Available at http://www.gpoaccess.gov/cfr/index.html

(accessed on October 2006)

US EPA. 40 CFR Part 414. Subpart G—Bulk Organic Chemicals. Washington, 

DC. Available at http://www.gpoaccess.gov/cfr/index.html (accessed on October 

2006)

US EPA. 40 CFR Part 414. Subpart I—Direct Discharge Point Sources That Use 

End-of-Pipe Biological Treatment. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 414. Subpart J—Direct Discharge Point Sources That Do 

Not Use End-of-Pipe Biological Treatment. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 415. Subpart F—Chlor-alkali Subcategory (Chlorine and 

Sodium or Potassium Hydroxide Production). Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 415. Subpart H—Hydrofluoric Acid Production 

Subcategory. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 418. Subpart A—Phosphate Subcategory. Washington, 

DC. Available at http://www.gpoaccess.gov/cfr/index.html (accessed on October 

2006)

US EPA. 40 CFR Part 418. Subpart B—Ammonia Subcategory. Washington, 

DC. Available at http://www.gpoaccess.gov/cfr/index.html (accessed on October 

2006)

US EPA. 40 CFR Part 418. Subpart E—Nitric Acid Subcategory. Washington, 

DC. Available at http://www.gpoaccess.gov/cfr/index.html (accessed on October 

2006)

US EPA. 40 CFR Part 422. Subpart D—Defluorinated Phosphate Rock 

Subcategory. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 422. Subpart E—Defluorinated Phosphoric Acid 

Subcategory. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)

US EPA. 40 CFR Part 458. Subpart A—Carbon Black Furnace Process 

Subcategory. Washington, DC. Available at 

http://www.gpoaccess.gov/cfr/index.html (accessed on October 2006)
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION 

 

DECEMBER 10, 2007 22

 

 WORLD BANK GROUP

Annex A: General Description of Industry Activities

This EHS Guideline for Large Volume Inorganic Compound

(LVIC) Manufacturing and Coal Tar Distillation includes 

Ammonia; Chlor-Alkali (i.e., chlorine, caustic soda, soda ash, 

etc.); Acids (Nitric, Hydrochlodric, Sulfuric, Hydrofluodric, 

Phosphoric); Carbon Black; and Coal Tar Distillation 

(naphthalene, phenanthrene, anthracene) sectors. It covers the 

production of major intermediates and products for the 

downstream industry covering many diversified sectors ranging 

from fertilizers to plastics. It is characterized by large volume 

productions, which can reach up to million ton per year and be 

manufactured in large facilities. 

Ammonia 32

About 80 % of ammonia (NH3) is currently used as the nitrogen 

source in fertilizers, with the remaining 20 % applied in several 

industrial applications, such as the manufacture of plastics, 

fibres, explosives, hydrazine, amines, amides, nitriles and other 

organic nitrogen compounds which serve as intermediates in 

dyes and pharmaceuticals manufacturing. Important inorganic 

products manufactured from ammonia include nitric acid, urea 

and sodium cyanide. Liquid ammonia is an important solvent 

and is also used as a refrigerant. 

Ammonia plants may be built as stand-alone or integrated with 

other plants at a site, typically with urea production. However 

recent trends include combined ammonia with methanol 

production. Hydrogen and / or carbon monoxide production can 

also be integrated with ammonia plants. An ammonia plant 

typically produces around 2,000 tonnes per day, but plants that 

can produce up to 3,400 tonnes per day have been built. 

 

32 EIPPCB. 2006b; EFMA. 2000a

The natural gas reforming with steam and air is the simplest and 

most efficient way of ammonia synthesis gas production and is 

today the most used.

Ammonia is produced by an exothermic reaction of hydrogen 

and nitrogen. This reaction is carried out in the presence of 

metal oxide catalysts at elevated pressure. Catalysts used in the 

process may contain cobalt, molybdenum, nickel, iron oxide /

chromium oxide, copper oxide / zinc oxide, and iron. The 

ammonia product, in liquefied form, is stored either in large 

atmospheric tanks at temperature of –33 degrees centigrade or 

in large spheres at pressures up to 20 atmospheres at ambient 

temperature. The raw material source of nitrogen is atmospheric 

air and it may be used in its natural state as compressed air or 

as pure nitrogen from an air liquefaction plant. Hydrogen is 

available from a variety of sources such as natural gas, crude 

oil, naphtha, or off gases from processes such as coke oven or 

refineries. 

Ammonia production from natural gas includes the following 

process steps: removal of trace quantities of sulfur in the 

feedstock; primary and secondary reforming; carbon monoxide 

shift conversion, removal of carbon dioxide, methanation, 

compression, ammonia synthesis, and ammonia product 

refrigeration. Carbon is removed in the form of concentrated 

CO2, which should preferably be used for urea manufacture or 

other industrial purposes to reduce its release to the 

atmosphere. 

Two other non conventional process routes include: (1) the 

addition of extra process air to the secondary reformer with 

cryogenic removal of the excess nitrogen, and (2) heatexchange autothermal reforming. The second process route has 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 23

 

 WORLD BANK GROUP

some environmental advantage because of the reduced need 

for firing in the primary reformer and the potential to lower 

energy consumption. It is a recent technology and, to date, built 

for a capacity of about 500 tonnes NH3 per day. 

Liquefied ammonia from production plants is either used directly 

in downstream plants or transferred to storage tanks. From 

storage the ammonia can be shipped to users, through road 

tankers, rail tank cars or ships. Ammonia is usually stored by 

using one or other of three methods:

• Fully refrigerated storage in large tanks with a typical 

capacity of 10,000 to 30,000 tonnes (up to 50,000)

• Pressurized storage spheres or cylinders with a capacity up 

to about 1,700 tonnes

• Semi-refrigerated tanks.

There are several storage types for refrigerated liquid products. 

The most important types are:

• Single containment: a single-wall insulated tank, usually 

with a containment bund around it;

• Double containment: tanks with two vertical walls, both 

designed to contain the stored liquid and withstand its 

hydrostatic pressure. The roof rests on the inner wall; and

• Full containment: closed storage tanks with two walls, as 

for double containment, but with the roof resting on the 

outer wall and using an adequate margin between 

operating and relief pressure.

Nitric Acid33

The production stages for nitric acid manufacture include the 

following: vaporizing liquid ammonia; mixing the vapor with air 

 

33 EIPPCB. 2006b; EFMA. 2000b.

and burning the mixture over a platinum/ rhodium catalyst; 

cooling the resultant nitric oxide (NO) and oxidizing it to nitrogen 

dioxide (NO2) with residual oxygen; and absorbing the nitrogen 

dioxide in water in an absorption column to react into nitric acid. 

Large-capacity plants normally have dual-pressure design (e.g.

medium-pressure combustion and high-pressure absorption), 

while small plants may have combustion and absorption 

conducted at the same pressure. High pressure in the 

absorption column reduces the nitrogen oxides (NOX) 

emissions. Generation of NOX and nitrous oxide (N2O), which is 

a greenhouse gas, in nitric acid plants is significant; however

catalytic conversion techniques can reduce the emission level 

by more than 80 percent. 

The recommended material for tanks, vessels and accessories 

is low carbon austenitic stainless steel. Transfer to transport 

vessels is typically via pumping or by gravity. Pressurizing for 

unloading large quantities should be avoided. Nitric acid is 

transported using rail tank cars, road tankers and less 

frequently, ships.

The typical capacity of modern plants for producing nitric acid is 

approximately 1,000 tons per day.

Sulfuric Acid34

The most important use of sulfuric acid (H2SO4) is in the 

phosphate fertilizer industry. Sulfuric acid is manufactured from 

sulfur dioxide (SO2) produced by combustion of elemental sulfur. 

Liquid sulfur is a product of the desulfurization of natural gas or 

the cleaning of coal flue-gas; another possible route is the 

melting of naturally occurring solid sulfur. Sulfur dioxide is also 

produced by the metals industry, through roasting and smelting 

processes generating off-gases with a sufficiently high 

 

34 EIPPCB. 2006b; EFMA. 2000c.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 24

 

 WORLD BANK GROUP

concentration of SO2 to allow direct processing to H2SO4. The 

thermal oxidizing process of spent acids used as raw materials 

is another route to produce SO2 and H2SO4. The exothermic 

oxidation of sulfur dioxide over several layers of a suitable 

catalyst (i.e., vanadium pentoxide) to produce sulfur trioxide 

(SO3) is the process used today in almost all sulfuric acid 

manufacturing plants. Modern plants can be designed to be very 

efficient in terms of sulfur dioxide conversion (more than 99%) 

and energy recovery.

Sulfuric acid is obtained from the absorption of SO3 and water 

into H2SO4 (with a concentration of at least 98%). SO3 is 

absorbed in an intermediate absorber installed after the second 

or third catalyst layer in a double contact process, where the 

gases are then conveyed to the final catalyst layer(s) and the 

SO3 formed here is absorbed in a final absorber. The final 

absorber is installed after the last catalyst layer in a single 

contact process. The warm acid produced is sparged with air in 

a column or in a tower to collect the remaining SO2 in the acid; 

the SO2 laden air is returned to the process.

Phosphoric Acid35

Phosphoric acid (H3PO4) is primarily used in the manufacture of 

phosphate salts (fertilizers and animal feed supplements). Two 

different processes can be used in the manufacture of 

phosphoric acid. In the first process, known as the thermal 

process, elemental phosphorus is produced from phosphate 

rock, coke and silica in an electrical resistance furnace and is 

then oxidized and hydrated to form the acid. Thermal-generated 

acid is considerably pure, but also expensive, and hence 

produced in small quantities, mainly for the manufacture of 

industrial phosphates.

 

35 EIPPCB. 2006b; EFMA. 2000d

The second types of processes, known as wet processes, are 

those digesting phosphate rocks with an acid (i.e. sulfuric, nitric 

or hydrochloric acid). The wet digestion of phosphate rock with 

sulfuric acid is the preferred process in term of volume. The tricalcium phosphate from the phosphate rock reacts with 

concentrated sulfuric acid to produce phosphoric acid and 

calcium sulfate that is an insoluble salt. The operating 

conditions are generally selected so that the calcium sulfate is 

precipitated as the dihydrate (DH) or hemihydrate (HH) form. 

The main production steps are the fo llowing: grinding of 

phosphate rock; reaction with sulfuric acid in a series of 

separate agitated reactors at a temperature of 70-80 °C; and 

filtration to separate the phosphoric acid from the calcium 

sulfate. 

Phosphoric acid is most commonly stored in rubber-lined steel 

tanks, although stainless steel, polyester and polyethylene-lined 

concrete are also used. Storage tanks are normally equipped 

with some means of keeping the solids in suspension to avoid 

costly cleaning of the tank.

Hydrofluoric Acid36

Hydrogen fluoride (HF) is produced in two forms, as anhydrous 

hydrogen fluoride and as aqueous hydrofluoric acid. The 

predominant form manufactured is hydrogen fluoride, a 

colorless liquid or gas that fumes when in contact with air and is 

water-soluble. Hydrogen fluoride is also a fortuitous by-product 

in the manufacture of superphosphate fertilizers. Hydrofluoric 

acid is used in glass etching and polishing, petroleum alkylation, 

and stainless steel pickling. Hydrofluoric acid is also used to 

produce fluorocarbons for the manufacture of resins, solvents, 

stain removers, surfactants, and pharmaceuticals.

 

36 EIPPCB. 2006b
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 25

 

 WORLD BANK GROUP

Hydrofluoric acid is manufactured by the reaction of acid-grade 

fluorspar (CaF2) with sulfuric acid (H2SO4). The endothermic 

reaction is conducted in horizontal rotary kilns externally heated 

to 200 to 250°C. Dry fluorspar and a slight excess of sulfuric 

acid are fed continuously to the front end of a stationary prereactor for mixing or directly to the kiln by a screw conveyor. 

Calcium sulfate (CaSO4) is removed through an air lock at the 

opposite end of the kiln.

The gaseous reaction products - hydrogen fluoride and excess 

H2SO4 from the primary reaction, and silicon tetrafluoride (SiF4), 

sulfur dioxide (SO2), carbon dioxide (CO2), and water vapor 

produced in secondary reactions - are removed from the front 

end of the kiln along with entrained particulate matter. The 

particulate matter is then removed from the gas stream and 

returned to the kiln. Sulfuric acid and water are removed in a 

pre-condenser. Hydrogen fluoride vapors are subsequently 

condensed in refrigerant condensers forming crude HF, which is 

sent to intermediate storage tanks. The remaining gas stream 

passes through a sulfuric acid absorption tower or acid 

scrubber, removing most of the remaining hydrogen fluoride and 

some residual sulfuric acid, which are also sent to intermediate 

storage. The gases exiting the acid scrubber are treated in 

water scrubbers, where both SiF4 and remaining HF are 

recovered as hexafluorosilicic acid (H2SiF6). The water scrubber 

tail-gases are passed through a caustic scrubber before being 

emitted to the atmosphere. The hydrogen fluoride and sulfuric 

acid are delivered from intermediate storage tanks to distillation 

columns, where the hydrofluoric acid is extracted at 99.98

percent purity. A final dilution step with water is needed to 

produce weaker concentrations (typically 70 to 80 per cent).

Anhydrous HF is a liquid which boils at 19.5 °C. The liquid HF is 

kept at low temperature, preferably below 15 °C, by cooling or 

by the installation of condensers in vent storage pipelines which 

condense the evaporating HF. Liquid HF is normally stored at 

atmospheric pressure in carbon steel tanks, where a thin 

protective layer of FeF2 is formed, preventing the tank walls from 

further corrosion. Liquid velocity in the pipelines should be 

below 1 m/s to avoid erosion of the FeF2 layer. Hydrofluoric acid 

with a concentration of at least 70 % is also stored in carbon 

steel tanks, whereas acid with concentrations of less than 70 % 

is stored in lined steel tanks or alternatively in polyethylene 

tanks.

Hydrochloric Acid37

Hydrochloric acid (HCl) is a versatile chemical used in a variety 

of chemical processes, including hydrometallurgical processing, 

chlorine dioxide syntheses, hydrogen production, and 

miscellaneous cleaning and etching operations. It is also a 

common ingredient in many chemical reactions, and a 

commonly used acid for catalyzing organic processes.

The acid is manufactured by several different processes. 

commonly applied production processes consist of reacting 

sodium chloride with sulfuric acid, or more recently, the acid is 

generated as a by-product of the chlorination reaction process 

(e.g., production of chlorinated solvents and organics).

Chlor-alkali38

The chlor-alkali industry produces chlorine (Cl2) and alkali (i.e., 

caustic soda or sodium hydroxide (NaOH) and potassium 

hydroxide (KOH)), by electrolysis of a salt solution, mainly using 

sodium chloride (NaCl) as feed or potassium chloride (KCl) for 

the production of potassium hydroxide. The chlor-alkali process 

is an important consumer of electrical energy. 

 

37 Australian Government, Department of the Environment and Heritage. 2004.

38 EIPPCB. 2001.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 26

 

 WORLD BANK GROUP

The main chlor-alkali manufacturing technologies are mercury, 

diaphragm and membrane cell electrolysis. In the chlorine 

process, chlorine gas leaving the electrolyzers is at 

approximately 80-90 oC and saturated with water vapor. It also 

contains impurities such as brine mist, nitrogen, hydrogen, 

oxygen, carbon dioxide and traces of chlorinated hydrocarbons. 

After direct or indirect cooling and impurities removal, chlorine is 

passed to the drying towers for drying with concentrated sulfuric 

acid. The gas is then compressed and liquefied at different 

pressure and temperature levels. Liquefied chlorine is stored in 

bulk tanks at ambient or low temperature. 

The membrane cell process has environmental advantages over 

the two older processes, in addition to be currently the most 

economically advantageous process. The anode and cathode 

are separated by a water-impermeable ion-conducting 

membrane. Brine solution flows through the anode compartment 

where chloride ions are oxidized to chlorine gas. The sodium 

ions migrate through the membrane to the cathode 

compartment which contains caustic soda solution. The 

demineralized water added to the catholyte circuit is hydrolyzed, 

and releases hydrogen gas and hydroxide ions. The sodium and 

hydroxide ions combine to produce caustic soda which is 

typically brought to a concentration of 32-35% by recirculating 

the solution before discharge from the cell. Higher 

concentrations are produced concentrating the caustic liquor by 

steam evaporation. The output of caustic soda is proportional to 

that of chlorine (1.128 tonnes of caustic soda (100%) are 

produced by electrolysis per tonne of chlorine). Because of the 

membrane, the caustic soda solution contain a very limited 

amount of salt due to migration of chloride, as in the diaphragm 

cell process. Depleted brine is discharged from the anode 

compartment and resaturated with salt.

The cathode material used in membrane cells is either stainless 

steel or nickel and the anodes used are metal. The cathodes are 

often coated with a catalyst that increases surface area and 

reduces over-voltage. Coating materials include Ni-S, Ni-Al, and 

Ni-NiO mixtures, as well as mixtures of nickel and platinum 

group meta ls. The membranes used in the chlor-alkali industry 

are commonly made of perfluorinated polymers.

Chlorine is often produced near consumers. Storage and 

transport of chlorine requires proper handling and use of best 

practice to minimize potential hazards. Chlorine is transported 

by pipe, road and rail.

Hydrogen is a co-product of the electrolysis of brine (28 kg for 1 

tonne of chlorine) and is generally used on-site as a 

combustible, sent as a fuel to other companies, or sold and 

transported as chemical. It can be used on integrated sites for 

certain applications because of its high purity, including 

synthesis of ammonia, methanol, hydrochloric acid, hydrogen 

peroxide, etc.

In addition to cell electrolysis, there are processing steps which 

are common to all technologies and include: salt unloading and 

storage, brine purification and resaturation, chlorine, caustic 

soda, and hydrogen processing.

The brine purification process consists of a primary system for 

the mercury and diaphragm technologies and an additional 

secondary system for membrane technology. This operation is 

needed to eliminate impurities (sulfate anions, cations of 

calcium, magnesium, barium and metals) that can affect the 

electrolytic process.

The primary brine purification uses sodium carbonate and 

sodium hydroxide to precipitate calcium and magnesium ions as 

calcium carbonate (CaCO3) and magnesium hydroxide 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 27

 

 WORLD BANK GROUP

(Mg(OH)2). Metals may also precipitate as hydroxide during this 

operation. Sodium sulfate may be controlled by adding calcium 

chloride (CaCl2) or barium salts (which however may represent 

a hazard due to their toxicity) to remove sulfate anions by 

precipitation of calcium sulfate (CaSO4) or barium sulfate 

(BaSO4). After precipitation, impurities are removed by 

sedimentation, filtration or a combination of both. Other 

possibilities to remove sulfates include ultra-filtration and brine 

purging.

The secondary brine purification consists of a polish filtration 

step and brine softening in an ion exchange unit generally with 

filters in order to sufficiently reduce the suspension matter and 

protect the ion-exchange resin from damage. The ion exchange 

chelating resin treatment is designed to decrease the alkaline 

earth metals to trace levels. The resin is periodically 

regenerated with high purity hydrochloric acid and sodium 

hydroxide solutions. 

Instead of diluting the remaining gases after partial 

condensation of the chlorine gas, the hydrogen is removed by 

means of a reaction with chlorine gas in a column. This step 

produces gaseous hydrochloric acid, which can be recovered in 

a hydrochloric acid unit.

Soda Ash39

Sodium carbonate (Na2CO3) or soda ash is a fundamental raw 

material to the glass, soaps and detergents, and chemicals

industries. Soda ash (calcined soda) is manufactured in two 

grades: ‘light soda ash’ and ‘dense soda ash’. Dense soda ash 

is mainly used in the glass industry and for economic 

transportation over long distances. The light form is used mainly 

for the detergent market and certain chemical intermediates.

 

39 EIPPCB. 2006a.

Soda ash is generally manufactured by large, highly integrated 

production units, with a plant capacity ranging from 150 to 1,200 

kt per year. 

The Solvay process (ammonia soda process) involves 

saturation of brine with ammonia and carbon dioxide gas. The 

process uses salt brine (NaCl) and limestone (CaCO3) as raw 

materials. Ammonia is almost totally regenerated and recycled. 

The main advantage of this process is the widespread 

availability of the relatively pure raw materials, which allow 

operating production units relatively close to the market.

The Solvay process produces ‘light soda ash’, with a pouring 

density of about 500 kg/m3. ‘Light soda ash’ is transformed by 

recrystallization first to sodium carbonate monohydrate, and 

then to ‘dense soda ash’ after drying (dehydration). Dense soda 

ash has a pouring density of about 1,000 kg/m3. Dense soda 

ash can also be produced by compaction.

Carbon Black40

Carbon black is produced by partial oxidation or thermal 

decomposition of hydrocarbons. About 65 – 70 % of the world’s 

consumption of carbon black is used in the production of tires 

and tire products for automobiles and other vehicles. Roughly 

25 - 30% is used for other rubber products and a small percent 

is used in plastics, printing ink, paint, paper and miscellaneous 

applications.

Carbon black differs from other carbon-based materials in many 

respects, especially in bulk density. Mixtures of gaseous or 

liquid hydrocarbons represent the raw materials preferable for 

industrial production with preference to aromatic hydrocarbons 

for better yields. 

 

40 EIPPCB. 2006a.
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 28

 

 WORLD BANK GROUP

The processes are divided into two groups: those employing 

incomplete or partial combustion and those based on thermal 

cracking. In the partial combustion processes, air is used to burn 

part of the feedstock, producing the energy required to carry out 

the pyrolysis, whereas in the thermal cracking process, heat is 

generated externally and introduced into the process.

The furnace black process is currently the most important 

production process. It accounts for more than 95% of the total 

worldwide production. It is a continuous process and its 

advantages are its great flexibility and its better economy 

compared to other process. The typical production rate is 

approximately 2,000 kg/h for a modern furnace black reactor. In 

furnace black, a heavy aromatic feedstock is injected by 

atomization into a high speed stream of combustion gases and 

partially burned and mostly cracked (45 – 65%) to produce 

carbon black and hydrogen at a temperature ranging from 1200 

to 1700° C. After quenching with water, carbon black is 

recovered by cyclones and bag filters, pellettized, dried and 

delivered to storage (silos) or shipped.

Coal Tar Distillation

Coal tar is currently almost totally distilled mainly in continuous 

stills that have daily capacities of 100–700 tons. It is a 

condensation product obtained by cooling the gas evolved in 

coal distillation (pyrolysis or carbonization of coal). Coal tar is a 

black viscous liquid denser than water. Coal-tar pitch is a black 

very viscous, semisolid, or solid residue from the distillation of 

coal tar. 

The coal tar product, which distills up to about 400°C at 

atmospheric pressure, is primarily a complex mixture of monoand polycyclic aromatic hydrocarbons, a proportion of which are 

substituted with alkyl, hydroxyl, amine and/or hydro sulfide 

groups, and to a lesser extent their sulfur-, nitrogen-, and 

oxygen-containing analogues. Tars produced at the lower coal 

carbonization temperatures also contain hydroaromatics, 

alkanes, and alkenes. The residue from the distillation is at least 

50% of the coal tar products by high temperature carbonization 

and consists of a continuation of the sequence of polynuclear 

aromatic, aromatic, and heterocyclic compounds, up to

molecules containing 20 to 30 rings.

Metal corrosion associated to continuous coal tar distillation is a 

typical issue to be considered in plant management. The 

ammonium salts (mainly ammonium chloride), associated with 

the entrained liquor remain in the tar after dehydration, tend to 

dissociate with the production of hydrochloric acid. This acid 

may deteriorate any equipment parts in which these vapors and 

steam are present above 240°C, including the condensers on 

the dehydration and fractionation columns. Corrosion is 

controlled by the addition of alkali (either sodium carbonate 

solution or caustic soda) to the tar.

A primary distillation product pattern at a tar-processing plant 

can give only one fraction, naphthalene oil taken between 180 

and 240°C, or two fractions, light creosote or middle oil (230–

300°C) and heavy creosote or heavy oil (above 300°C) between 

the naphthalene oil and pitch.

The higher boiling cresylic acids are mixtures of cresols or 

xylenols with higher boiling phenols. Their main uses are in 

phenol-formaldehyde resins, solvents for wire-coating enamels, 

metal degreasing agents, froth-flotation agents, and synthetic 

tanning agents.

Naphthalene is the principal component of coke-oven tars and 

the only component that can be concentrated to a reasonably 
Environmental, Health, and Safety Guidelines

LARGE VOLUME INORGANIC COMPOUNDS MANUFACTURING AND COAL TAR DISTILLATION

 

DECEMBER 10, 2007 29

 

 WORLD BANK GROUP

high content on primary distillation41. Naphthalene oils can be

further upgraded by several methods, mainly based on 

crystallization of the primary naphthalene oil to upgrade to 

phthalic grade quality or to convert the latter into the purer 

chemical grade anthracene oils. Naphthalene has been

traditionally used for the production of phthalic anhydride, ßnaphthol and dye stuff intermediates. More recently, 

naphthalene has been used in condensation products from 

naphthalene sulfonic acids, utilizing formaldehyde as additives 

to improve the flow properties of concrete. Another application is 

the production of diisopropylnaphthalenes.

Crude anthracene is isolated from coke-oven anthracene oils. 

Where the anthracene oil gives only a limited residue at 360°C, 

the oil is diluted using naphthalene drained oil or a light wash oil 

and this blend is cooled to 35°C. The resulting solid–liquid slurry 

is filtered or centrifuged to give a crude anthracene oil 

containing 40–45% anthracene.

The recovery of tar chemicals leaves residual oils, including 

heavy naphtha, dephenolated carbolic oil, naphthalene drained 

oil, wash oil, strained anthracene oil, and heavy oil. These are 

blended to give creosote oils, which have been used as timber 

preservatives Coal-tar creosote is also a feedstock for carbon 

black manufacture. Other smaller markets for creosote are for 

fluxing coal tar, pitch, and bitumen.

 

41 Naphthalene oils from coke-oven tars generally contain 60–65% of 

naphthalene.