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, 19931.0 INTRODUCTION The U.S. Environmental Protection Agency (U.S. EPA) is in the process of developing aFederal Implementation Plan (FTP) which is designedto achieve attainment of the ozone standard forthe Sacramento nonattainment area. As part ofthis process, MichiganCaliforniaLumber 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 andto help the El Dorado County Air Pollution Control District (APCD) meets its Clean Air Act mandated requirementto determine RACT for all major sources, EPA plans to propose aRACT rule forMichigan-California Lumber Company in the Sacramento FTP. This document presents the determination ofRACT for reducing VOC emissions from a wood waste boiler at the Michigan-CaliforniaLumber Company facility located at 3970 Carson Road in Camino, California. This document also discusses the basis for the determination, provides an overview ofpotential control technologies and costeffectiveness, and describes the impacts associated with the implementation ofthe RACT VOC control measures. 1.1 Source Description Michigan-CaliforniaLumber 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, PonderosaPine, 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 ofcommercial timber each day. The characteristics ofthe lumber and normal operations (i.e., species, dimensions, processing rates, etc.) generally depend on the demands and conditions ofthe retail and wholesale market.

US. EPA WA9 Michigan-California RACT TSDDuring the milling process, bark is removed from the logs, which are then transported to and cut in the sawmill. The rough-cutboards from the sawmill are sorted, dried in pressurized andheated kilns, and most are then planed to established specifications for commercial sale. The largerbark and waste woodpieces are reducedto 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 alarge outdoor storage area. These waste wood materials are then fed via gravity onto a conveyorbelt system, which moves the material to an indoor storage building or “fuel house.” From the fuel house, the wood waste is transportedto the boilerhouse for use as boilerfuel. Steam generatedby the boilers is used for heat in the wood drying kilns. The kilns operate undervarying steam loads, timeperiods, and conditions based on the characteristics ofthe lumber (Michigan-California, 1993). The VOC emission source thatis subjectto this RACT determination is the main waste-woodboiler unit (Boiler #3) in use at the facility. In 1990, this boilerrepresented the single largest reported source ofVOC 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-CaliforniaLumber 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 forback-up support when the main unit (Boiler #3) is not operable during maintenance or upset conditions (approximately 240 hours peryear). In these dutch-oven boilers, fuel is gravity fed into the primary combustion chamber where it accumulates in a cone-shapedpile on a flat grate through which underfire air is fed. Afterthe 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 notbeen conducted.
U.S. EPA WA9 Michigan-California RACT TSD 2However, emissions reportedto the El Dorado APCD have assumed similarVOC exhaust rates as Boiler#3. The emissions reported in 1990 forBoilers #1 and#2 were 7.4 tons of VOC peryear, each (AirResources Board, 1991). Boiler #3 is a spreader-stokerboilerthatwas manufacturedby Erie IronWorks, Inc. in 1965. As reportedby the facility in 1993, this boiler operates approximately 8,450 hours peryear. During scheduled maintenance and cleaning, the boiler is shut down twice eachyear. Wastebark and wood are the only source offuel forthe unit. Fuel is fed into the boilerthrough five separate, self-adjusting, auger drives and feed chutes, which extendfrom a hopperbelowthe conveyor system to the boiler. Wood fuels are blown evenly across the boilerby air ducts located near each ofthe five fuel inlets. These fuel/airinlets provide about 10% ofthe combustion airfor the boiler, with the remainder suppliedby forced draft underfire air (Wagner, 1993). Existing overfire air inlets on the sides ofBoiler#3 havebeen sealed and are not used. Combustion ofsmallerparticles (e.g., sawdust and small wood chips) typically occurs in suspension above the boiler grate andthe heavierpieces ofbark and wood are burned on the grate surface. This fuel on the grate lies in arelatively level fuel “bed” that varies from four to eight inches in thickness. The thickness ofthe fuel in various areas throughout the boilerplate surface varies depending on the size ofthe fuel 

### andthe relative velocity ofthe airpassing 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 ofBoiler#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 maintainedbetween 5-7 percent. Boiler operators are in attendance during all hours ofoperation and they manually adjustthe 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 TSDfacility was given an operating variance from PM emissions limits in orderto install an electrostatic precipitator (ESP) on the boiler to construct anew boiler and an electrical cogeneration facility in cooperation with the local utilities district. This proposed projectis still underreview and a substantial change in the boiler characteristics could change boiler emissions. Boiler #3 has arated operating capacity of 125,000 pounds ofsteam perhour (lb-steam/hr) and apermitted capacity of 110,000 lb-steam/hr. Typically, the system operates at an average production rate of90,000 lb-steam/hr (Knight, 1993). As noted above, steam generation, output, and delivery are regulatedby 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 ofthe states annual inspection and operating permit program andthe remaining lifespan ofthis unit is not limitedbased on recent inspections. 1.1.2 Fuel Characteristics The waste wood fuel used in theboiler is generally a composite ofseveral tree species, each with different characteristics. The heating value ofwaste wood fuels varies with the amount ofinorganic material (e.g., soil and rocks), the moisture content ofthe fuel mixture, and the volatile organic matterin the wood. The average heating value ofwood 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 ofthe wood waste fuel used by Michigan CaliforniaLumber 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/orthe storage conditions at the time ofthe tests. Fuel moisture is an important factorthat affects the overall efficiency ofthe combustion process in the boiler. 1.2 Emissions

U.S. EPA WA9 Michigan-CaIifornii RACT TSD 4VOC emissions, as tested and reported as total organic gases forthe 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 atthe facility in July 1988, July 1992, andNovember 1993. The results ofthese tests are presentedin Table 1. The 1988 source testhas been used as the basis forthe facility’s annual operating permit, inventory, 

### and fees. Forthe 1990 baseline emissions inventory, the El Dorado APCD submitted a summary ofthe source test results from 1988 to ARB, and as ofOctober 1993, the emissions inventory forthis stationary source had notbeen 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 peryear (tpy). During this test, the waste wood fuel consisted ofWhite Fir with an average moisture content ofabout 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 testresults forBoiler#3 indicated a substantial decrease in the average amount ofVOC emissions comparedto 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 PonderosaPine wood and bark wastes with an average estimated moisture content of35.6 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 currentVOC emissions from Boiler #3 are 11.2 lbs/hr or approximately 48.8 tpy. During this recenttest, the fuel consisted ofWhite Fir with an average measured moisture content ofapproximately 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 of8,720 hours.

U.S. EPA WA9 Michigan-California RACT TSI) 6steam/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 datafor 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 ofthis document. Unless the cogeneration facility projectmentionedin Section 1.1.1 results in the replacement ofBoiler #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-CaliforniaLumber Company does nothave add-on controls for VOC emissions. As noted previously, the boiler exhaust system is equipped with two multiclones and amagnetic 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, MichiganCaliforniaLumber Company made several operational changes to Boiler#3 

### and the wood waste fuel in order to increase the efficiency ofthe unit (Gomez, 1993). As reportedby the facility, some ofthe modifications implementedthat could reduce VOC emissions from Boiler #3 include the following:

• New Striker Plates on the Stoker—A change to provide abetter spread offuel in the combustion zone, and grates with less distinct separation offine materials and smallermaterials into certain areas on the grate.

• Rebuilt and Timed Pulsator on the Stoker—An improvement intended to improve the spread offuel on the grate and therefore increase combustion efficiency.
U.S. EPA WA9 Michigan-California RACT TSD 7• New Stoker Hoppers —This change was intended to reduce fuel size classification and separation in the fuel auger feed system, thereby reducing the concentration offine 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 abetter mix ofair on the grates.

• New Master Controller—An improvementthat may reduce the impacts ofload changes during normal operation oftheboiler. 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 forboiler 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 mustbe metby the boiler.

• Reduced Fuel Moisture Content—This improvement includes the continued reduction ofwater 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 ofthe VOC reduction can be attributed to these equipment andprocess improvements.

U.S. EPA WA9 Michigan-California RACT TSD 82.0 RACT RECOMMENDATION It is recommended thatthe following determination (see Appendix A) be defined as RACT forthe operation ofBoiler#3 atMichigan-CaliforniaLumber Company. The RACT standards in Appendix A forMichigan-CaliforniaLumber Company is summarized as follows: An emissions limit of 150 parts per million by volume (ppmv) (corrected to 12% carbon dioxide) ofVOCs in the stack exhaust stream. This RACT standard is based on VOC emissions as measured forMichiganCalifornia’s Boiler #3 and similar wood waste spreader-stokerboilers 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 ofthe moisture content ofthe 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 ofapproximately 59.6 percent. During the emissions test

### in 1992, an average VOC emission rate of218.4 ppmv (as correctedto 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, amaximum VOC concentration limit of 150 ppmv is reasonable for Michigan CaliforniaLumber Company’s Boiler #3. Pacific Oroville Power, Inc. (POPI) operates a similarboiler system in Oroville, California. This facility operates two Zurn-Nepco® spreader-stokerboilers that were manufactured in approximately 1986. Similar to Michigan-CaliforniaLumber Company, these boilers are used to burn waste woodproducts. 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 aproduction rate thatranges from

US. EPA WA9 Michigin-Ca1ifornii RACT TSD 9

# 0
95,000 to 105,000 lbs-steam/hour (each), andthe average moisture content ofthe wood waste fuel varies from 40-45 percent. The excess oxygen concentration in the exhaust airon these boilers is maintained at about 2-3%, and underfire airis 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-stokerboilers were measured during seven tests and resulted in ranges from 37 to 48 parts permillion, by volume (ppmv) ofVOC when reported as propane (ARB, 1990a) (i.e., 111 ppmv to 144 ppmv when reported as methane). The results ofthe source tests completedby 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-CaliforniaLumber Company is approximately 20 years olderthan the POPI units and the design and operating requirements ofthe olderboiler do not reasonably permitVOC emissions levels similarto newerboilers (Wagner, 1993). Additionally, the fluctuations in steam loads at the drying kilns and the variability ofthe operating conditions atMichigan-Californialimits the consistency associated with operating an electric generation facility. Therefore, the VOC emission status presentedfor this RACT determinationprovides for 150 ppmv, or approximately 1.04 times the maximum reported VOC exhaust concentration from the POPI facility. 2.1 Description ofAvailable Control Technologies SixVOC control technology alternatives were evaluated forthe RACT determination ofMichigan-CaliforniaLumber Company. These are briefly summarizedin this section.

U.S. EPA WA9 Michigan-California RACT 1 SD 102.1.1 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 ofopposite 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 awater wall curtain, removes PM, 

### and can be usedto collect some water-soluble organic compounds. 2.1.2 Natural Gas-Fired Afterburners An afterburner is aliquid or gaseous fuel-firedburner located above the main combustion chamber ofthe 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 ofoxides ofnitrogen (NO). Some advantages ofan afterburner are the increased combustion efficiency of the furnace andthe ease ofregulating boiler temperatures. Disadvantages ofthis technology include the high cost offuel, difficulties in retrofitting boilers to use the fuel, 

### and relatively high operating costs. 2.1.3 Addition ofOverfire Air “Overfire air” is forced airthat 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 ofoverfire airuse include increased combustion efficiency and reduced fuel usage.

U.S. EPA WA9 Michigan-Cahfornia RACT TSD 11Michigan-California’s Boiler #3 is equipped with overfire air inlets on the side walls. However, these units are notused in orderto reduce the amount ofexcess oxygen in the system (Wagner, 1993). 2.1.4 Reductions ofFuel Moisture Content Fuel moisture contentis an important factor in the regulation ofany boiler. Fluctuations in fuel moisture can make it difficult to maintain consistent firing conditions because fuel and air feed settings cannotbe changedto immediately maintain a constant combustion rate. Drier fuels generally combust athighertemperatures; therefore, the amount ofuncombusted 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 contentof 50 percent. Average fuel moisture can be regulated through anumber ofoperational managementtechniques. These alternatives include the following:

• Covering the fuel storage piles during wintermonths;

• Maintaining aminimum fuel storage residence time (e.g., three weeks) to initiate heat generation and homogenous moisture distribution in the waste woodpile;

• Mixing drier fuels (e.g., planer shavings) with wetter fuels to maintain a consistent fuel moisture contentofthe fuel;

• Reducing the use ofwater as a coolant and lubricant in the sawmill to minimize excessive wetting ofthe 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 12The advantages ofregulating fuel moisture through one ormore ofthe measures listed above includes the maintenance ofsteady firing conditions in the boiler, more efficient and reduced fuel usage, and generally lower capital costs. Several disadvantages ofregulating 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 ofthe availability offuel that is regulated formoisture content (Leiby, 1993). 2.1.5 Replacement ofBoiler #3 with a New Boiler Another alternative forVOC 

### and other criteriapollutant emissions reductions includes the replacement ofthe existing boiler at Michigan-CaliforniaLumber Company with anew spreader-stokerboiler. This would require the demolition and removal ofBoiler#3, modifications to the existing fuel feed and transportation system, and installation ofthe new boiler. Generally, it is anticipatedthatthe emissions reductions wouldbe achievedthrough improved combustion efficiency based on more advanced boiler designs and controls. Although, specific VOC emissions reductions for this alternative cannotbe estimated, installation ofboilers similar to those used atthe POPI facility in OroviHe, California, could reduce VOC emissions to approximately 140 ppmv. Advantages ofreplacing the existing boilerinclude the following:

• Increased overall combustion efficiency andboiler operation, and extended lifespan ofthe facility,

• Reduced annual waste wood fuel usage;

• Better control ofcombustion conditions andboiler 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) 13Some ofthe disadvantages associated with installing anew boilerinclude the high capital costs associated with boiler replacement, greateroverall 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 ofthe existingboiler, operating parameters, and combustion conditions. The purpose ofthis evaluation program and recommended actions wouldbe to develop shortterm 

### and long-term plans for effective management and use oftheboiler andto minimize incomplete combustion. This evaluation could include areview andtesting by manufacturers and/orboiler maintenance representatives to periodically appraise the operation ofBoiler#3. Recommendations for improvements may include some ofthe alternatives discussed above (e.g., overfire air and fuel moisture controls). Michigan-CaliforniaLumber Company staffwould be responsible for application ofnew combustion alternatives and controls, as determined by each objective boiler assessment. 2.2 TechiioIoical Feasibility ofControl Options The technological feasibility ofeach ofthe control alternatives discussedin Section 2.1 was evaluated by considering Michigan-CaliforniaLumber 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 averageproduction rate of90,000 ibs steam/hr:

U.S. EPA WA9 Michigan-California RACT TSD 14• Air flow from the multiclones 

### and stack ofapproximately 34,000 standard cubic feetper minute (scfm);

• VOC loading in the exhaust stream ofapproximately 15 lbs/hr (based on 1992 test);

• Operating rate ofapproximately 8,720 hours peryear;

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

• Stack exhausttemperature ofapproximately 380°F. The results ofthe technological feasibility analysis for each ofthe alternative VOC control measures forBoiler #3 are discussed below. According to avendor, installation ofa wet ESP for the purpose ofVOC emissions reductions from Boiler #3 is not technically feasible as this is aparticulate 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 ameans for collecting and treating wastewater sludge from the ESP unit. Construction and use ofa 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 notbe likely to reduce VOC emissions in the exhaust stream due to the limited residence time in the afterburner flame zone. An afterburnerwould also require substantial fuel resources and would likely increase total NO and CO 2 emissions from Boiler#3. Overfire airhas been used in Boiler #3 in the past and the system couldbe reactivated to improve combustion conditions in the furnace. The effectiveness ofoverfire 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.
US. EPA WA9 Michigui-Ca1ifornia RACT TSD 15

# S
Regulating fuel moisture contentis atechnically feasible alternativeto increase combustion efficiency and reduce VOC emissions from Boiler#3. The facility has reported that several fuel managementtechniques (e.g., water coolantreductions and coveredpiles) are currently in place to maintain a consistent moisture content. Additional feasible control measures could include aminimum storage pile residence time ofthree weeks, 

### and closely managed mixing offine materials and drier fuels with wetter fuels. The demolition ofBoiler #3 

### and replacement with anew boileris atechnically feasible alternative to improve the operational andpollutant emissions characteristics ofthe facility. Although anew wood firedboiler would likely result in less criteria andtoxic pollutant emissions, the economic requirements forreplacing the existing boiler do not appear tojustify the reduction in VOC emissions. The final control alternative, boiler control evaluation and modification, is procedural and similarto the activities presented in the previous technologies for improving combustion efficiency. Although this is aprocedural 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-CaliforniaLumber Company has contracted consulting engineers and boilertechnicians to assist them with the proper maintenance and operation ofthis boiler. 2.3 Summary ofFeasible Technolo2ies Ofthe six technologies examined for attaining the VOC emissions levels for Boiler#3 at the Michigan-CaliforniaLumber Company, the following four alternatives were determined to be technologically feasible:

• Evaluation and use ofoverfire air injection;

• Regulation offuel moisture;

• Installation ofanew boiler; and
U.S. EPA WA9 Michigan-California RACT TSD 16Scheduled review and modification ofthe boiler operation characteristics to maximize combustion efficiency. As noted above, the implementation ofthe combustion process review and fuel moisture regulation forBoiler #3 has resulted in much ofthe 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 173.0 COST-EFFECTIVENESS The following discussion briefly summarizes the economic considerations 

### and estimated cost-effectiveness forthe feasibleVOC reduction alternatives identifiedin Section 2.3. 3.1 Addition ofOverfire Air Installation ofoverfire air system inlets on the sides ofBoiler#3 would require relatively minor connections. The existing ports in the rear wall ofthe furnace would likely be usable for this alternative. Based on reported capital costs ofapproximately $5,000 for a five-portoverfire air system on a small wood-fired furnace, the cost ofinstalling overfire air on the back wall ofBoiler #3 would range from $10,000 to $20,000 in capital costs, and 10% or $1,000 to $2,000 peryear in maintenance and operating costs. It is notpossible to estimate the quantity ofVOC reductions associated with this alternative; therefore, the cost-effectiveness (i.e., dollars/ton VOC) ofthis alternative cannotbe calculated. 3.2 Regulation ofFuel Moisture Content Michigan-CaliforniaLumber 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 andhave helpedto minimize poor combustion. Unfortunately, the costs offuel management alternatives already implemented atthe facility cannotbe estimated since they are part of daily staffactivities. The regulation offuel moisture is considered economically feasible for this RACT determination.

U.S. EPA WA9 Michigan-California RACT TSD 183.3 Replacement ofthe Existing Boiler The capital cost for turnkey” installation ofanewboilerwas estimated using input from avendor based on the same load and operating parameters as the existing boiler. A new waste wood-fired spreader-stokerboilerwith arated capacity of 125,000 ibs steam/hour, amaximum operating pressure of300 lbs ofsteam, and complete electronic controls, is estimated to cost from $6,250,000 to $7,500,000 (Holmstrom, 1993). This capital cost estimate does not includethe demolition costs associated with the old unit; annual operating costs were assumedto be the same as the existing boiler. Based on estimated emissions from similarly sized 

### and “new” boilers atthe POPI facility in Oroville, anewboiler atMichigan-CaliforniaLumber Company could achieve VOC emissions reductions ofapproximately 22 tpy from 1992 measured levels. Averaging the estimated capital cost over a 30-yearperiod forthe boiler at an annual interest rate of8%, the capital recovery cost ofanewboiler would range from $555,000 to $666,000 peryear or $25,000 to $30,000 perton ofVOC. Given this high relative cost and associated (uncalculated) demolition costs, this alternative is not economically feasible for VOC control atthis facility. 3.4 Boiler Control Review and Modifications An annual review ofthe operating conditions, stack analyses, and operating details would costMichigan-CaliforniaLumber Company from $3,000 to $12,000. Forthe pastthree to fouryears, they have reportedly employedthe services ofa combustion consultantto inspect and adjustboiler operations. This alternative has reportedly proven to be economically feasible and cost-effective, giving reductions ofup to 203 tons ofVOC between 1988 and 1993, most ofwhich are reportedly attributedto more efficient combustion (Knight, 1993; Wagner, 1993).

U.S. EPA WA9 Michigan-Cahfornia RACT TSD 194.0 IMPACTS 4.1 Economic The economic impacts associated withperiodic reviews andboiler adjustments, regulating fuel moisture, and the reinstatement ofoverfire air would notbe significant for reducing VOC emissions from Boiler #3. Each ofthese 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 affectedMichigan-CaliforniaLumber 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 ofthe emission estimates forthe 1990 baseline Inventory, implementation ofthe RACT standards in Appendix A will reduce VOC emissions by approximately 200 tpy atthe Michigan-California Lumber Company. This represents a 79°/a reduction from the VOC emissions inventory of 251 .7 tpy for Boiler#3 (as reportedto 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 ofthe 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 205.0 REFERENCES
Air Resources Board, 1992. Determination ofReasonablyAvailable Control Technology and BestAvailable Retrofit Control TechnologyforMetal Container, Closure, and Coil Coating Operations, ARB/SSD-93-OO1. Criteria Pollutants Branch, Stationary Source Division, Sacramento, California. Air Resources Board, 1990a. Evaluation Teston a Wood Waste FiredIncineratoratPac.fIc Oroville PowerInc. Engineering Evaluation Branch, Monitoring and Laboratory Division, Sacramento, California. Air Resources Board, l990b. Evaluation Test on a Wood Waste FiredincineratoratKoppers Company, Oroville, California. Engineering Evaluation Branch, Monitoring and Laboratory Division, Sacramento, California. Air Resources Board, 1990c. Evaluation Test on a Wood Waste FiredIncineratorat LouisianaPacific HardboardPlant, Orovi/le, California. Engineering Evaluation Branch, Monitoring and Laboratory Division, Sacramento, California. Air Resources Board, 1990d. Evaluation Test on Twin FluidizedBed Wood Waste Fueled Combustors Locatedin Central Caifornia. Engineering Evaluation Branch, Monitoring 

### and Laboratory Division, Sacramento, California. Air Resources Board, 1991. Inventory Records Emissions byDevice WithinFacility 1989 DraftEmission Inventoty. Air Resources Board. AirResources Board, 1984. AirPollution Control atResource RecoveryFacilities. Project Review Branch, Stationary Source Division, Sacramento, California. Babcock andWilcox, 1975. Steam—its Generation and Use. Revised 38th edition. BWR, 1992. Emission testing results from a source test conducted on July 22, 1992. Preparedby 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-CaliforniaLumber 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 21Knight, 1993. Transmittal ofresponses to information request from Bob Knight, MichiganCaliforniaLumber Company, Camino, California, to Allan J. Priest, Radian Corporation, Sacramento California. October 20. Leiby, 1993. Personal communication between ScottLeiby, SierraPacific Industries, Redding, California, and Allan J. Priest, Radian Corporation, Sacramento, California. October 27. Michigan-California, 1993. Personal communicationbetween Bob Knight, Jim Hardy, Michigan-CaliforniaLumber Company, Camino, California, and Allan J. Priest 

### andL. Pat Nelson, Radian Corporation, Sacramento, California. October 11. U.S. Environmental Protection Agency, 1993. Emission FactorDocumentationforAP-42 Section 1.6 Wood Waste Combustion in Boilers. Preparedby Edward Aul and Associates, Inc. 

### andE.H. Pechan and Associates forthe Office ofAir Quality Planning and Standards (OAQPS), Research Triangle Park, North Carolina. U.S. Environmental Protection Agency, 1990. OAQFS Control CostManual, Fourth Edition. EPA-450/3-90-006, Office ofAir and Waste Management, Office ofAir 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 RogerWalker, Pacific Oroville PowerInc., Oroville, California. and Allan J. Priest, Radian Corporation, Sacramento, California. October 22.

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