RCN: 654-028-09-04

RACT DETERMINATION

FOR

MICHIGAN-CALIFORNIA LUMBER COMPANY

TECHNICAL SUPPORT DOCUMENT

FINAL REPORT

Contract #68-D3-0033

Work Assignment #9

Prepared for:

U.S. EPA Region IX

Air and Toxics Division

75 Hawthorne Street

San Francisco, CA 9405

Prepared by:

Radian Corporation

10389 Old Placerville Road

Sacramento, CA 95827

December 17, 1993
1.0 INTRODUCTION

The U.S. Environmental Protection Agency (U.S. EPA) is in the process of

developing a Federal Implementation Plan (FTP) which is designed to achieve attainment of

the ozone standard for the Sacramento nonattainment area. As part of this process, MichiganCalifornia Lumber Company in Camino, California, has been identified as a major source of

volatile organic compounds (VOCs) in the Sacramento nonattainment area which is not

currently subject to a reasonably available control technology (RACT) rule. In order to find

emissions reductions for the attainment demonstration and to help the El Dorado County Air

Pollution Control District (APCD) meets its Clean Air Act mandated requirement to determine

RACT for all major sources, EPA plans to propose a RACT rule for Michigan-California

Lumber Company in the Sacramento FTP.

This document presents the determination of RACT for reducing VOC

emissions from a wood waste boiler at the Michigan-California Lumber Company facility

located at 3970 Carson Road in Camino, California. This document also discusses the basis

for the determination, provides an overview of potential control technologies and costeffectiveness, and describes the impacts associated with the implementation of the RACT

VOC control measures.

1.1 Source Description

Michigan-California Lumber Company has been processing lumber and

manufacturing timber at the facility in Camino, California, for more than 30 years. Various

coniferous tree species, including Sugar Pine, Douglas Fir, Ponderosa Pine, and White Fir, are

harvested, transported to the facility, and processed for commercial sale. This facility

processes from 700,000 to 1 million board feet of commercial timber each day. The

characteristics of the lumber and normal operations (i.e., species, dimensions, processing rates,

etc.) generally depend on the demands and conditions of the retail and wholesale market.

US. EPA WA9 Michigan-California RACT TSD
During the milling process, bark is removed from the logs, which are then

transported to and cut in the sawmill. The rough-cut boards from the sawmill are sorted,

dried in pressurized and heated kilns, and most are then planed to established specifications

for commercial sale. The larger bark and waste wood pieces are reduced to smaller, nearly

uniform sizes by a “hog” machine, producing “hogged wood” (U.S. EPA, 1993). The waste

bark, hogged wood, planing chips, and sawdust generated during the lumber manufacturing

activities are collected and accumulated in a large outdoor storage area. These waste wood

materials are then fed via gravity onto a conveyor belt system, which moves the material to

an indoor storage building or “fuel house.” From the fuel house, the wood waste is

transported to the boiler house for use as boiler fuel. Steam generated by the boilers is used

for heat in the wood drying kilns. The kilns operate under varying steam loads, time periods,

and conditions based on the characteristics of the lumber (Michigan-California, 1993).

The VOC emission source that is subject to this RACT determination is the

main waste-wood boiler unit (Boiler #3) in use at the facility. In 1990, this boiler represented

the single largest reported source of VOC emissions in the El Dorado County APCD’s

inventory. No other stationary sources (i.e., back-up boilers and fuel tanks) or fugitive

evaporative sources from the wood milling process are addressed in this RACT determination.

1.1.1 Boiler Characteristics

Michigan-California Lumber Company uses three boilers to generate steam for

the on-site drying kilns. Boilers #1 and #2 are relatively small dutch-oven type boilers that

are only used for back-up support when the main unit (Boiler #3) is not operable during

maintenance or upset conditions (approximately 240 hours per year). In these dutch-oven

boilers, fuel is gravity fed into the primary combustion chamber where it accumulates in a

cone-shaped pile on a flat grate through which underfire air is fed. After the volatile organic

materials are gasified in this primary stage, the air enters the secondary furnace chamber,

where gaseous products are burned (U.S. EPA, 1993). Since Boilers #1 and #2 are not

operated except during emergencies and maintenance, source testing has not been conducted.

U.S. EPA WA9 Michigan-California RACT TSD 2
However, emissions reported to the El Dorado APCD have assumed similar VOC exhaust

rates as Boiler #3. The emissions reported in 1990 for Boilers #1 and #2 were 7.4 tons of

VOC per year, each (Air Resources Board, 1991).

Boiler #3 is a spreader-stoker boiler that was manufactured by Erie Iron Works,

Inc. in 1965. As reported by the facility in 1993, this boiler operates approximately 8,450

hours per year. During scheduled maintenance and cleaning, the boiler is shut down twice

each year. Waste bark and wood are the only source of fuel for the unit. Fuel is fed into the

boiler through five separate, self-adjusting, auger drives and feed chutes, which extend from a

hopper below the conveyor system to the boiler. Wood fuels are blown evenly across the

boiler by air ducts located near each of the five fuel inlets. These fuel/air inlets provide about

10% of the combustion air for the boiler, with the remainder supplied by forced draft

underfire air (Wagner, 1993). Existing overfire air inlets on the sides of Boiler #3 have been

sealed and are not used.

Combustion of smaller particles (e.g., sawdust and small wood chips) typically

occurs in suspension above the boiler grate and the heavier pieces of bark and wood are

burned on the grate surface. This fuel on the grate lies in a relatively level fuel “bed” that

varies from four to eight inches in thickness. The thickness of the fuel in various areas

throughout the boiler plate surface varies depending on the size of the fuel and the relative

velocity of the air passing through the spreaders. The average combustion temperature in

Boiler #3 is approximately 1,700°F with some fluctuations due to changes in fuel and steam

load characteristics (Knight, 1993).

Operation of Boiler #3 is controlled by a computer, which regulates the air and

fuel feed rates relative to the steam demands from the drying kilns. Excess oxygen in the

exhaust stream is continuously monitored and maintained between 5-7 percent. Boiler

operators are in attendance during all hours of operation and they manually adjust the boiler

as needed. Add-on particulate matter (PM) emission controls include two multiclone units, in

series, and a sand separation system with two Erie magnetic vibrators. As of 1993, the

U.S. EPA WA9 Michigin-Ca1ifornia RACT TSD
facility was given an operating variance from PM emissions limits in order to install an

electrostatic precipitator (ESP) on the boiler to construct a new boiler and an electrical

cogeneration facility in cooperation with the local utilities district. This proposed project is

still under review and a substantial change in the boiler characteristics could change boiler

emissions.

Boiler #3 has a rated operating capacity of 125,000 pounds of steam per hour

(lb-steam/hr) and a permitted capacity of 110,000 lb-steam/hr. Typically, the system operates

at an average production rate of 90,000 lb-steam/hr (Knight, 1993). As noted above, steam

generation, output, and delivery are regulated by an automated system that adjusts according

to the established operating conditions for each drying kiln control system. Boiler #3 is

currently operated within the parameters of the states annual inspection and operating permit

program and the remaining lifespan of this unit is not limited based on recent inspections.

1.1.2 Fuel Characteristics

The waste wood fuel used in the boiler is generally a composite of several tree

species, each with different characteristics. The heating value of waste wood fuels varies with

the amount of inorganic material (e.g., soil and rocks), the moisture content of the fuel

mixture, and the volatile organic matter in the wood. The average heating value of wood

waste ranges from 8,000 to 10,000 British thermal units (Btu)/lb on a dry basis, or from 4,000

to 5,000 Btu/lb on a wet basis (assuming approximately 50% moisture, by weight) (U.S. EPA,

1993). The measured fuel moisture content of the wood waste fuel used by Michigan

California Lumber Company was 50.1% in 1988, 37% in 1992, and 40.6% in 1993. This

difference in moisture can be attributed to the different tree species combusted in the boiler

and/or the storage conditions at the time of the tests. Fuel moisture is an important factor that

affects the overall efficiency of the combustion process in the boiler.

1.2 Emissions

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VOC emissions, as tested and reported as total organic gases for the calendar

years 1988 through 1993 are briefly discussed in this section. The estimated annual VOC

emissions from Boiler #3 have been derived from stack exhaust samples and analyses

conducted at the facility in July 1988, July 1992, and November 1993. The results of these

tests are presented in Table 1. The 1988 source test has been used as the basis for the

facility’s annual operating permit, inventory, and fees. For the 1990 baseline emissions

inventory, the El Dorado APCD submitted a summary of the source test results from 1988 to

ARB, and as of October 1993, the emissions inventory for this stationary source had not been

updated.

Based on average test results from three stack samples, the estimated 1988

VOC emissions from Boiler #3 were 57.7 lbs/hr or 251.7 tons per year (tpy). During this

test, the waste wood fuel consisted of White Fir with an average moisture content of about 50

percent. The production rate during the test was 90,600 lbs-steam/hour and the average VOC

concentration from the stack was 585.27 parts per million, by volume (ppmv) (BWR, 1988) or

570.53 ppmv (corrected to 12% carbon dioxide).

In 1992, the exhaust stream test results for Boiler #3 indicated a substantial

decrease in the average amount of VOC emissions compared to the 1988 test results. The

average VOC emissions from three samples (as required by EPA Method 25) in 1992 were

14.7 lbs/hour or 64. 1 tpy. During the test, the fuel used in Boiler #3 was Ponderosa Pine

wood and bark wastes with an average estimated moisture content of 35.6 percent. The

average operating rate during the tests was 87,000 lb-steam/hour and VOC concentrations

from the stack ranged from 85 ppmv to 252 ppmv, with an average of 178 ppmv (BWR,

1992) or 218.4 ppmv (corrected to 12% carbon dioxide).

The source test results obtained in November 1993 estimate that current VOC

emissions from Boiler #3 are 11.2 lbs/hr or approximately 48.8 tpy. During this recent test,

the fuel consisted of White Fir with an average measured moisture content of approximately

44.4 percent. The average production rate during the three source tests was 88,300 lbs

U.S. EPA WA9 Michian-Ca1ifornia RACT TSD 5
Table 1

1988, 1992, and 1993 VOC Emissions

for Michigan-California Lumber Company’s Boiler #3

1988 VOC Emissionsa 1992 VOC Emissionsb 1993 VOC Emissionsc

585.3 ppmv 178 ppmv 138 ppmv

(570.53 ppmv corrected)d (218.4 ppmv corrected)d (127.4 ppmv corrected)’

57.7 lbs/hr 14.7 lbs/hr 11.2 lbs/hr

251.7 tons/yre 64.1 tons/yre 48.8 tons/yre

Source: BWR and Associates. Source Test Results (July 19, 1988) (fuel moisture = 50%). h Source: BWR and Associates. Source Test Results (July 22, 1992) (fuel moisture = 37%).

Source: BWR and Associates, Source Test Results (November 2, 1993) (fuel moisture = 40.6%). d Corrected to 12% carbon dioxide (see Appendix C).

Conservatively based on reported annual boiler usage of 8,720 hours.

U.S. EPA WA9 Michigan-California RACT TSI) 6
steam/hr and measured VOC concentrations ranged from 96 ppmv to 183 ppmv, with an

average of 138 ppmv (BWR, 1993) or 127.4 ppmv (corrected to 12% carbon dioxide).

The emissions data for 1988, 1992, and 1993 are summarized in Table 1, and

calculations to support the corrected concentration estimates in Table 1 are presented in

Appendix C of this document. Unless the cogeneration facility project mentioned in Section

1.1.1 results in the replacement of Boiler #3, projected operations and emissions in 1999 and

2005 will likely be the same as 1993 for this facility.

1.3 Existing Emission Controls

The Michigan-California Lumber Company does not have add-on controls for

VOC emissions. As noted previously, the boiler exhaust system is equipped with two

multiclones and a magnetic sand clarifier to control PM emissions. Although these

mechanisms may temporarily reduce some organic compounds that condense in the exhaust

stream, these technologies have no measurable control efficiency for VOCs,

1.4 Special Considerations

Between the source tests in July 1992 and November 1993, MichiganCalifornia Lumber Company made several operational changes to Boiler #3 and the wood

waste fuel in order to increase the efficiency of the unit (Gomez, 1993). As reported by the

facility, some of the modifications implemented that could reduce VOC emissions from Boiler

#3 include the following:

• New Striker Plates on the Stoker—A change to provide a better

spread of fuel in the combustion zone, and grates with less distinct

separation of fine materials and smaller materials into certain areas on

the grate.

• Rebuilt and Timed Pulsator on the Stoker—An improvement

intended to improve the spread of fuel on the grate and therefore

increase combustion efficiency.

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• New Stoker Hoppers —This change was intended to reduce fuel size

classification and separation in the fuel auger feed system, thereby

reducing the concentration of fine materials in the stoker.

• Sawdust Separator in the Sawmill—This reduces the amount of

sawdust and fine materials in the fuel and is intended to provide a better

mix of air on the grates.

• New Master Controller—An improvement that may reduce the impacts

of load changes during normal operation of the boiler. The previous

controller reportedly responded too quickly to load changes, which

caused excessive fuel changes in the boiler.

• New Oxygen Analyzer—As noted above, this continuous monitor

provides more accurate information for boiler operation and adjustments.

• Kiln Load Study—The facility is evaluating alternative drying kiln

control systems in order to provide effective steam distribution and

reduce load surges that must be met by the boiler.

• Reduced Fuel Moisture Content—This improvement includes the

continued reduction of water used to cool and lubricate saws, and

covering the fuel storage piles with plastic sheeting during winter

months (Gomez, 993; Knight, 1993).

Since fuel characteristics and output were generally similar during the two tests

conducted in 1992 and 1993, much of the VOC reduction can be attributed to these

equipment and process improvements.

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2.0 RACT RECOMMENDATION

It is recommended that the following determination (see Appendix A) be

defined as RACT for the operation of Boiler #3 at Michigan-California Lumber Company.

The RACT standards in Appendix A for Michigan-California Lumber Company is

summarized as follows:

An emissions limit of 150 parts per million by volume (ppmv)

(corrected to 12% carbon dioxide) of VOCs in the stack exhaust stream.

This RACT standard is based on VOC emissions as measured for MichiganCalifornia’s Boiler #3 and similar wood waste spreader-stoker boilers used in California. In

1993, the average emissions on the VOC emissions from Boiler #3 exhaust were reduced

from 1988 and 1992 levels by improvements in the combustion process and regulation of the

moisture content of the fuel. The improved combustion efficiency obtained through modified

boiler operation and steam load controls resulted in a measured decrease in average VOC

emissions between the 1988 and 1992 emission tests of approximately 59.6 percent. During

the emissions test in 1992, an average VOC emission rate of 218.4 ppmv (as corrected to

12% carbon dioxide) was measured in the boiler exhaust stream (reported as methane).

Additionally, the changes and improvements made since the 1992 test, have resulted in

measured VOC concentration of 127.4 ppmv, an additional 41.6% decrease in exhaust

concentration. Therefore, a maximum VOC concentration limit of 150 ppmv is reasonable for

Michigan California Lumber Company’s Boiler #3.

Pacific Oroville Power, Inc. (POPI) operates a similar boiler system in Oroville,

California. This facility operates two Zurn-Nepco® spreader-stoker boilers that were

manufactured in approximately 1986. Similar to Michigan-California Lumber Company, these

boilers are used to burn waste wood products. However, the steam is used to generate

electricity and, therefore, the operating load on these boilers is more steady than Boiler #3 at

Michigan-California. The POPI boilers are operated at a production rate that ranges from

US. EPA WA9 Michigin-Ca1ifornii RACT TSD 9
0

95,000 to 105,000 lbs-steam/hour (each), and the average moisture content of the wood waste

fuel varies from 40-45 percent. The excess oxygen concentration in the exhaust air on these

boilers is maintained at about 2-3%, and underfire air is supplemented with overfire air

injection ports that are located approximately 2 to 3 feet above the grate (Walker, 1993).

The VOC concentrations in the exhaust from the POPI spreader-stoker boilers

were measured during seven tests and resulted in ranges from 37 to 48 parts per million, by

volume (ppmv) of VOC when reported as propane (ARB, 1990a) (i.e., 111 ppmv to 144 ppmv

when reported as methane). The results of the source tests completed by the ARB in 1990

for the POPI facility were the basis for emission factors developed for AP-42, Section 1.6

(U.S. EPA, 1993).

Although they are similar, the boiler operated by Michigan-California Lumber

Company is approximately 20 years older than the POPI units and the design and operating

requirements of the older boiler do not reasonably permit VOC emissions levels similar to

newer boilers (Wagner, 1993). Additionally, the fluctuations in steam loads at the drying

kilns and the variability of the operating conditions at Michigan-California limits the

consistency associated with operating an electric generation facility. Therefore, the VOC

emission status presented for this RACT determination provides for 150 ppmv, or

approximately 1.04 times the maximum reported VOC exhaust concentration from the POPI

facility.

2.1 Description of Available Control Technologies

Six VOC control technology alternatives were evaluated for the RACT

determination of Michigan-California Lumber Company. These are briefly summarized in this

section.

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2.1.1 Wet ESP

An ESP is an add-on emissions control device that introduces an electrical

charge to suspended particles in the boiler exhaust stream. These particles migrate to a

collecting electrode of opposite polarity while subjected to a diverging electric field (U.S.

EPA, 1993). The particulate materials attached to the electrodes are then dislodged and

collected. A ‘wet” ESP introduces a water wall curtain, removes PM, and can be used to

collect some water-soluble organic compounds.

2.1.2 Natural Gas-Fired Afterburners

An afterburner is a liquid or gaseous fuel-fired burner located above the main

combustion chamber of the boiler. Fuel and air are burned in the afterburner, which combusts

unburned carbons (carbon monoxides and hydrocarbons) in the exhaust stream, and can also

be used to regulate combustion temperatures and control formation of oxides of nitrogen

(NO).

Some advantages of an afterburner are the increased combustion efficiency of

the furnace and the ease of regulating boiler temperatures. Disadvantages of this technology

include the high cost of fuel, difficulties in retrofitting boilers to use the fuel, and relatively

high operating costs.

2.1.3 Addition of Overfire Air

“Overfire air” is forced air that is often added to the combustion chamber

above the fuel. This air mixes with the furnace gases and increases the turbulence that is

required for complete combustion (Babcock and Wilcox, 1975). The advantages of overfire

air use include increased combustion efficiency and reduced fuel usage.

U.S. EPA WA9 Michigan-Cahfornia RACT TSD 11
Michigan-California’s Boiler #3 is equipped with overfire air inlets on the side

walls. However, these units are not used in order to reduce the amount of excess oxygen in

the system (Wagner, 1993).

2.1.4 Reductions of Fuel Moisture Content

Fuel moisture content is an important factor in the regulation of any boiler.

Fluctuations in fuel moisture can make it difficult to maintain consistent firing conditions

because fuel and air feed settings cannot be changed to immediately maintain a constant

combustion rate. Drier fuels generally combust at higher temperatures; therefore, the amount

of uncombusted organic gases emitted from the process is less than that emitted using wetter

fuels. Boiler #3 is adjusted and operated to use fuel that has an average moisture content of

50 percent.

Average fuel moisture can be regulated through a number of operational

management techniques. These alternatives include the following:

• Covering the fuel storage piles during winter months;

• Maintaining a minimum fuel storage residence time (e.g., three weeks)

to initiate heat generation and homogenous moisture distribution in the

waste wood pile;

• Mixing drier fuels (e.g., planer shavings) with wetter fuels to maintain a

consistent fuel moisture content of the fuel;

• Reducing the use of water as a coolant and lubricant in the sawmill to

minimize excessive wetting of the sawdust; and

• Installing fuel dryers to dry fuel mixtures through heating and

mechanical means before combustion in the boiler.

U.S. EPA WA9 Michigan-California RACT TSD 12
The advantages of regulating fuel moisture through one or more of the measures listed above

includes the maintenance of steady firing conditions in the boiler, more efficient and reduced

fuel usage, and generally lower capital costs.

Several disadvantages of regulating fuel moisture include the additional labor

involved in handling the fuel and the capital and operating costs associated with fuel covers

and drying systems. Additionally, fuel dryers tend to be ineffective in regulating fuel

moisture in different waste wood types and fuel demand is continuous regardless of the

availability of fuel that is regulated for moisture content (Leiby, 1993).

2.1.5 Replacement of Boiler #3 with a New Boiler

Another alternative for VOC and other criteria pollutant emissions reductions

includes the replacement of the existing boiler at Michigan-California Lumber Company with

a new spreader-stoker boiler. This would require the demolition and removal of Boiler #3,

modifications to the existing fuel feed and transportation system, and installation of the new

boiler. Generally, it is anticipated that the emissions reductions would be achieved through

improved combustion efficiency based on more advanced boiler designs and controls.

Although, specific VOC emissions reductions for this alternative cannot be estimated,

installation of boilers similar to those used at the POPI facility in OroviHe, California, could

reduce VOC emissions to approximately 140 ppmv. Advantages of replacing the existing

boiler include the following:

• Increased overall combustion efficiency and boiler operation, and

extended lifespan of the facility,

• Reduced annual waste wood fuel usage;

• Better control of combustion conditions and boiler output during surges

in steam load demands by the drying kilns; and

• Reduced criteria and toxic pollutant emissions.

U.S. EPA WA9 Michigan-California RACI 1 SI) 13
Some of the disadvantages associated with installing a new boiler include the

high capital costs associated with boiler replacement, greater overall annual operating costs,

and relatively small reductions in emissions.

2.1.6 Boiler Control Evaluation and Modification

The final alternative includes actions that would result from an in-depth

technical evaluation of the existing boiler, operating parameters, and combustion conditions.

The purpose of this evaluation program and recommended actions would be to develop shortterm and long-term plans for effective management and use of the boiler and to minimize

incomplete combustion. This evaluation could include a review and testing by manufacturers

and/or boiler maintenance representatives to periodically appraise the operation of Boiler #3.

Recommendations for improvements may include some of the alternatives discussed above

(e.g., overfire air and fuel moisture controls).

Michigan-California Lumber Company staff would be responsible for

application of new combustion alternatives and controls, as determined by each objective

boiler assessment.

2.2 TechiioIoical Feasibility of Control Options

The technological feasibility of each of the control alternatives discussed in

Section 2.1 was evaluated by considering Michigan-California Lumber Company’s specific

operating conditions and process parameters. These include the following:

• Exhaust stack gas composition (based on 1988, 1992, and 1993

analyses).

• Rated maximum capacity of 125,000 lbs-steam/hour, permitted capacity

of 110,000 lbs-steam/hr, and average production rate of 90,000 ibs

steam/hr:

U.S. EPA WA9 Michigan-California RACT TSD 14
• Air flow from the multiclones and stack of approximately 34,000

standard cubic feet per minute (scfm);

• VOC loading in the exhaust stream of approximately 15 lbs/hr (based

on 1992 test);

• Operating rate of approximately 8,720 hours per year;

• Average boiler furnace temperature of 1,700°F; and

• Stack exhaust temperature of approximately 380°F.

The results of the technological feasibility analysis for each of the alternative VOC control

measures for Boiler #3 are discussed below.

According to a vendor, installation of a wet ESP for the purpose of VOC

emissions reductions from Boiler #3 is not technically feasible as this is a particulate control

device with very limited VOC capture capability. In addition to a substantial modification to

the exhaust collection system and ductwork, the facility would need to develop a means for

collecting and treating wastewater sludge from the ESP unit.

Construction and use of a natural gas-fired afterburner above the combustion

zone in Boiler #3 would not be technically feasible due to the relatively short design height of

the boiler. In addition to the design restrictions, an afterburner would not be likely to reduce

VOC emissions in the exhaust stream due to the limited residence time in the afterburner

flame zone. An afterburner would also require substantial fuel resources and would likely

increase total NO and CO2 emissions from Boiler #3.

Overfire air has been used in Boiler #3 in the past and the system could be

reactivated to improve combustion conditions in the furnace. The effectiveness of overfire air

could feasibly be tested in coordination with other factors such as fuel feed rates, load rate

changes, fuel moisture changes, and other measures to maximize the combustion efficiency in

the boiler. It is anticipated that such a continuous evaluation and testing program could

further reduce emissions from the boiler.

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S

Regulating fuel moisture content is a technically feasible alternative to increase

combustion efficiency and reduce VOC emissions from Boiler #3. The facility has reported

that several fuel management techniques (e.g., water coolant reductions and covered piles) are

currently in place to maintain a consistent moisture content. Additional feasible control

measures could include a minimum storage pile residence time of three weeks, and closely

managed mixing of fine materials and drier fuels with wetter fuels.

The demolition of Boiler #3 and replacement with a new boiler is a technically

feasible alternative to improve the operational and pollutant emissions characteristics of the

facility. Although a new wood fired boiler would likely result in less criteria and toxic

pollutant emissions, the economic requirements for replacing the existing boiler do not appear

to justify the reduction in VOC emissions.

The final control alternative, boiler control evaluation and modification, is

procedural and similar to the activities presented in the previous technologies for improving

combustion efficiency. Although this is a procedural and management alternative, it is a

feasible measure for further identifying control measures that may reduce the emissions of

uncombusted hydrocarbons from Boiler #3. To date, Michigan-California Lumber Company

has contracted consulting engineers and boiler technicians to assist them with the proper

maintenance and operation of this boiler.

2.3 Summary of Feasible Technolo2ies

Of the six technologies examined for attaining the VOC emissions levels for

Boiler #3 at the Michigan-California Lumber Company, the following four alternatives were

determined to be technologically feasible:

• Evaluation and use of overfire air injection;

• Regulation of fuel moisture;

• Installation of a new boiler; and

U.S. EPA WA9 Michigan-California RACT TSD 16
Scheduled review and modification of the boiler operation

characteristics to maximize combustion efficiency.

As noted above, the implementation of the combustion process review and fuel moisture

regulation for Boiler #3 has resulted in much of the decreased VOC emissions between 1988

and 1992. Further emissions changes due to reported improvements since 1992 have also

resulted in substantial VOC emissions reductions.

U.S. EPA WA9 Michigan-California RACT TSD 17
3.0 COST-EFFECTIVENESS

The following discussion briefly summarizes the economic considerations and

estimated cost-effectiveness for the feasible VOC reduction alternatives identified in

Section 2.3.

3.1 Addition of Overfire Air

Installation of overfire air system inlets on the sides of Boiler #3 would require

relatively minor connections. The existing ports in the rear wall of the furnace would likely

be usable for this alternative. Based on reported capital costs of approximately $5,000 for a

five-port overfire air system on a small wood-fired furnace, the cost of installing overfire air

on the back wall of Boiler #3 would range from $10,000 to $20,000 in capital costs, and 10%

or $1,000 to $2,000 per year in maintenance and operating costs.

It is not possible to estimate the quantity of VOC reductions associated with

this alternative; therefore, the cost-effectiveness (i.e., dollars/ton VOC) of this alternative

cannot be calculated.

3.2 Regulation of Fuel Moisture Content

Michigan-California Lumber Company has implemented some measures to

regulate the moisture content in the fuel. According to facility staff, measures such as

covered fuel piles and water coolant reductions have resulted in more consistent fuel and have

helped to minimize poor combustion. Unfortunately, the costs of fuel management

alternatives already implemented at the facility cannot be estimated since they are part of

daily staff activities. The regulation of fuel moisture is considered economically feasible for

this RACT determination.

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3.3 Replacement of the Existing Boiler

The capital cost for turnkey” installation of a new boiler was estimated using

input from a vendor based on the same load and operating parameters as the existing boiler.

A new waste wood-fired spreader-stoker boiler with a rated capacity of 125,000 ibs

steam/hour, a maximum operating pressure of 300 lbs of steam, and complete electronic

controls, is estimated to cost from $6,250,000 to $7,500,000 (Holmstrom, 1993). This capital

cost estimate does not include the demolition costs associated with the old unit; annual

operating costs were assumed to be the same as the existing boiler.

Based on estimated emissions from similarly sized and “new” boilers at the

POPI facility in Oroville, a new boiler at Michigan-California Lumber Company could

achieve VOC emissions reductions of approximately 22 tpy from 1992 measured levels.

Averaging the estimated capital cost over a 30-year period for the boiler at an annual interest

rate of 8%, the capital recovery cost of a new boiler would range from $555,000 to $666,000

per year or $25,000 to $30,000 per ton of VOC. Given this high relative cost and associated

(uncalculated) demolition costs, this alternative is not economically feasible for VOC control

at this facility.

3.4 Boiler Control Review and Modifications

An annual review of the operating conditions, stack analyses, and operating

details would cost Michigan-California Lumber Company from $3,000 to $12,000. For the

past three to four years, they have reportedly employed the services of a combustion

consultant to inspect and adjust boiler operations. This alternative has reportedly proven to be

economically feasible and cost-effective, giving reductions of up to 203 tons of VOC between

1988 and 1993, most of which are reportedly attributed to more efficient combustion (Knight,

1993; Wagner, 1993).

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4.0 IMPACTS

4.1 Economic

The economic impacts associated with periodic reviews and boiler adjustments,

regulating fuel moisture, and the reinstatement of overfire air would not be significant for

reducing VOC emissions from Boiler #3. Each of these methods are economically and

technologically feasible, and several measures (including combustion review and moisture

regulation) have already reportedly been successfully evaluated and applied to the operation.

To date, these measure have not adversely affected Michigan-California Lumber Company’s

economic position in the commercial timber market.

4.2 Emission Reductions

Based on 1988 source test results that were used as the basis of the emission

estimates for the 1990 baseline Inventory, implementation of the RACT standards in

Appendix A will reduce VOC emissions by approximately 200 tpy at the Michigan-California

Lumber Company. This represents a 79°/a reduction from the VOC emissions inventory of

251 .7 tpy for Boiler #3 (as reported to the ARB for this stationary source in the 1989 through

1993 annual emissions inventories).

4.3 Other Impacts

No other adverse environmental impacts associated with implementation of the

RACT standards with respect to global warming, plant and animal life, noise levels, land use,

light and glare, natural resources, or sociological factors were identified.

U.S. EPA WA9 Michigan-California RACT TSD 20
5.0 REFERENCES

Air Resources Board, 1992. Determination ofReasonably Available Control Technology and

Best Available Retrofit Control Technology for Metal Container, Closure, and Coil Coating

Operations, ARB/SSD-93-OO1. Criteria Pollutants Branch, Stationary Source Division,

Sacramento, California.

Air Resources Board, 1 990a. Evaluation Test on a Wood Waste Fired Incinerator at Pac.fIc

Oroville Power Inc. Engineering Evaluation Branch, Monitoring and Laboratory Division,

Sacramento, California.

Air Resources Board, l990b. Evaluation Test on a Wood Waste Fired incinerator at Koppers

Company, Oroville, California. Engineering Evaluation Branch, Monitoring and Laboratory

Division, Sacramento, California.

Air Resources Board, 1 990c. Evaluation Test on a Wood Waste Fired Incinerator at

Louisiana Pacific Hardboard Plant, Orovi/le, California. Engineering Evaluation Branch,

Monitoring and Laboratory Division, Sacramento, California.

Air Resources Board, 1 990d. Evaluation Test on Twin Fluidized Bed Wood Waste Fueled

Comb ustors Located in Central Caifornia. Engineering Evaluation Branch, Monitoring and

Laboratory Division, Sacramento, California.

Air Resources Board, 1991. Inventory Records Emissions by Device Within Facility 1989

Draft Emission Inventoty. Air Resources Board.

Air Resources Board, 1984. Air Pollution Control at Resource Recovery Facilities. Project

Review Branch, Stationary Source Division, Sacramento, California.

Babcock and Wilcox, 1975. Steam—its Generation and Use. Revised 38th edition.

BWR, 1992. Emission testing results from a source test conducted on July 22, 1992.

Prepared by BWR Associates, Inc., Medford, Oregon.

BWR, 1988. Emission testing results from a source test conducted on July 19, 1988.

Prepared by BWR Associates, Inc., Medford, Oregon.

Gomez, 1993. Letter from Dennis Gomez, Michigan-California Lumber Company to El

Dorado County APCD and ARE. April.

Holmstrom, 1993. Personal communication between Harold Holmstrom, Zurn-Nepco Energy

Systems, Erie, Pennsylvania, and Allan J. Priest, Radian Corporation, Sacramento, California.

October 22.

U.S. EPA WAO Michigan-California RACT TSD 21
Knight, 1993. Transmittal of responses to information request from Bob Knight, MichiganCalifornia Lumber Company, Camino, California, to Allan J. Priest, Radian Corporation,

Sacramento California. October 20.

Leiby, 1993. Personal communication between Scott Leiby, Sierra Pacific Industries,

Redding, California, and Allan J. Priest, Radian Corporation, Sacramento, California. October

27.

Michigan-California, 1993. Personal communication between Bob Knight, Jim Hardy,

Michigan-California Lumber Company, Camino, California, and Allan J. Priest and L. Pat

Nelson, Radian Corporation, Sacramento, California. October 11.

U.S. Environmental Protection Agency, 1993. Emission Factor Documentation for AP-42

Section 1.6 Wood Waste Combustion in Boilers. Prepared by Edward Aul and Associates, Inc.

and E.H. Pechan and Associates for the Office of Air Quality Planning and Standards

(OAQPS), Research Triangle Park, North Carolina.

U.S. Environmental Protection Agency, 1990. OAQFS Control Cost Manual, Fourth Edition.

EPA-450/3-90-006, Office of Air and Waste Management, Office of Air Quality Planning and

Standards (OAQPS), Research Triangle Park, North Carolina.

Wagner, 1993. Personal communication between Wayne Wagner, Zurn-Nepco Inc., Portland,

Oregon, and Allan J. Priest, Radian Corporation, Sacramento, California. October 21.

Walker, 1993. Personal communication between Roger Walker, Pacific Oroville Power Inc.,

Oroville, California. and Allan J. Priest, Radian Corporation, Sacramento, California.

October 22.

U.S. EPA WA9 Michigan-California RACT TSD 22