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**Date:** March 5 , 2013 **Subject:** Secondary ( Environmental and Energy ) Impacts for Wool Fiberglass Manufacturing NESHAP

– Area Sources 40 CFR 63, Subpart NN

– Supplemental Proposal EPA Contract No. EP

- D

- 11

- 084 ; EPA Work Assignment No. 1

- 0 7 RTI Project No. 021 3199 .00 1 .00 7
**From:** Cindy

Hancy Dave Reeves
**To:** Susan Fairchild, EPA/OAQPS/SPPD/MMG

**I. Introduction**  The purpose of this memorandum is to document the estimated environmental and energy impacts associated with the proposed National Emission Standard for Hazardous Air Pollutants ( NESHAP ) 40 CFR 63, Subpart NN

- Wool Fiberglass Manufacturing for area sources

. Secondary impacts include the solid waste, water, wastewater generated and the electricity required to operate air pollution co ntrol devices , as well as, the resultant greenhouse gas (GHG) emissions from controls or work practices required b y the NESHAP.
**II. Water,**  **Wastewater , and Solid Waste**  **Impacts** The EPA estimates that three gas - fired glass

- melting furnaces at area source wool fiberglass manufacturing facilities will need to install a caustic scrubber to meet the proposed chromium compound emission limit for Subpart NN

. The water required to operate the scrubber and the solid and wastewater generated b y the effluent were ca lculated for the three units. The 2010 information collection request, sent to all wool fiberglass manufacturers, requested that facilities provide detailed information for each control device. For scrubbers, facilities were asked to provide gas and water flow rates, liquid to gas ratios, pressure drop, wastewater generation, and several other operating parameters for each of their existing scrubber s . Append ix 1 contains a complete list of all the information EPA requested for scrubbers, however, because th e majority of facilities submitted this information as confidential business information (CBI), facilit y responses are not included in this memo. The EPA compiled these ICR responses, and using the operating parameters (also considered CBI) of the three furnaces estimated to need caustic scrubbers, estimated the amount of water needed to operate the scrubbers, as well as the wastewater and solid was te that would be generated. The calculated impact estimates are provided in Table 1.2

**Table 1. Estimated Water and Solid Waste Impacts for Caustic**  **Scrubbers on Fur**  **n aces**  Impacts per facility Total industry impacts Water flow rate into scrubber (gpm) 1 155 465 Percent of scrubber water from recycled facility wastewater 1 60 60 Total non

- recycled water necessary (gallons per year) 2 33 M 99 M Total scrubber effluent rate (gpm) 1 4.9 4.9 Percent scrubber wastewater recycled 1 50 50 Total wastewater generated (gallons per year) 3 1.3M 4.8M Total solid waste collected (lb/yr) 1 468,000 1.4M (1) Estimates from ICR responses . (2) Calculation: 155 (gpm) x 60 (min/hr) x 8760 (hrs/yr) x (100%

- 60%). (3) Calculation: 4.9 (gpm) x 60 (min/hr) x 8760 (hrs/yr) x (100%

- 50%). **III. Energy**  **Impacts and**  **GHG Em**  **issions from Electricity Usage** The amount of electricit y required to operate a control device (i.e., caustic scrubber) was calculated using the information summarized in Table 1. The electricity costs associated with operating a scrubber derive from fan requirements to overcome the pressure drop in the column, ductwork, and other parts of the control sy stem, and pump requirements to re

- circulate the water. According to the EPA’s Ai r Pollution Control Cost Manual, fan and pump energy requirements can be calculated by using equation 3

- 1 and 3

- 2, respectivel y.

Equation 3

- 1

= 1

. 17 10 Equation 3

- 2

= 0

. 746 2

. 52 10
Where Gi is the gas flow rate entering the scrubber, P is the total pressure drop, Li is the liquid flow rate entering the scrubber , P is the pressure of the pump which we assume to be 60 ft of water and e is the efficiency of the device

. The av erage gas flow rate entering the scrubber for the three furnaces is 17,000 acfm, the average estimated pressure drop for the scrubber is 7.8 inches of water, and the average estimated liquid flow is 155 gallons per minute. Using equations 3

- 1 and 3

- 2 and a n estimated efficiency of 0.7 for both the pump and the fan, we estimated the energy required to be 43kWh for the fan, and 3kWh for the pump.

= ( 1

. 17 10 ) ( 17 , 000 ) ( 7

. 8 )

0

. 7 = 22 h

= ( 0

. 746 ) ( 2

. 52 1 0 ) ( 60 ) ( 155 )

0

. 7 = 2 h

Assuming operating hours is 8,760 per y ear, the total annual energy required for each scrubber is:3 24 h 8 , 760 h
= 210 , 000 h / This results in 631,000 kWh per y ear for all three scrubbers. We used the natural gas emission factor (in kilograms [kg]/MMBtu) from the General Stationary Fuel Combustion Sources subpart (40 CFR part 98, subpart C) of the Greenhouse Gas Reporting Rule (listed in Table 2) to estimate the secondary emissions for CO 2 , CH 4 , and N 2 O.

**Table 2. Emission Factors from General Stationary Fuel Combustion Sources (40 CFR part 98, subpart C)** 

**Fuel Default CH**  **4**

**emission factor (kg CH**  **4 /MM**  **Btu) Default N**  **2 O** 

**emission factor (kg**  **N 2**  **O/MM Btu)**  **Default CO**  **2**

**emission factor**  **(kg C O**  **2 /MM**  **Btu)** Natural Gas 1.0 × 10 −03 1.0 × 10 −04 53.02 Global warming potentials of 1 for CO 2 , 21 for CH 4 , and 310 for N 2 O (from Table A

- 1 to subpart A of part 98) were used to estimate CO 2 equivalent emissions (CO 2 eq). First we converted kWh to MMBtu as follows: 631 , 000 h 0

. 0034 h = 2 , 100 Using the values in Table 2 we estimated CH 4 , N 2 0, and CO 2 , emissions as 2.1 kg/ yr (5 lbs/ yr ), 0.21 kg/ yr (0.5 lbs/ yr ), and 111,000 kg/ yr (245,000 lbs/y r), respectively . We then calculated the CO 2 eq emissions based on the global warming potentials above as follows:

= 245000 + 21 5 + ( 310 0

. 5 )
This results in 245,300 lbs CO 2eq per y ear for all three scrubbers.

## Appendix 1. ICR Questionnaire for Scrubbers

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**FORM C -**  **2 AI**  **R POLLUTION CONTROL**
**II. Scrubber -**  **NA** For each scrubber: Scrubber 1 Scrubber 2 Process line(s) (identification name/number) Equipment/process(es) controlled. Include emission point designations (e.g., E3, E4 from plot plan) Latitude (decimal degrees, six decimal places) Longitude (decimal degrees, six decimal places) Stack or vent height (units) Stack or vent diameter (units) Manufacturer and model Date of original installation Type (e.g., venturi, orifice) Gas flow rate to scrubber (acfm @ ° F) Inlet gas temperature ( ° F) Outlet gas temperature ( ° F) Inlet grain loading (gr/dscf) Outlet grain loading (gr/dscf) Average stack opacity (%) Wa ter flow rate to scrubber (gpm) Percent of scrubber water from recycled wastewater Source of scrubbing water and type of pretreatment. Substance(s) added as part of pretreatment and amount used (gpm or lbs/hr) HAP composition of wastewater (mg/L) Concentration (mg/L) of dissolved and suspended solids in scrubbing water Scrubbing water temperature ( ° F) Liquid/gas ratio (gal/10 3 acfm) Pressure drop across scrubber (in. H 2 O gauge) Amount of wastewater generated (gpd) Amount of wastewater recycled (gpd) Amount of wastewater disposed of (gpd) Method of wastewater disposal Quantity of solid waste collected (lbs/yr) Quantity of solid waste recycled (lbs/yr) Quantity of solid waste disposed of (lbs/yr) Method of solid waste disposal Vendor guarantee on scrubber efficiency (attach copy) Nature and frequency of preventive maintenance procedures Problems experienced with control device within the last five years; how were problems solved? Continuous monitoring method(s) used to monitor scrubber performance, inclu ding parameters monitored