COMMONWEALTH OF VIRGINIA

I. INTRODUCTION & BACKGROUND

A. Company Background

Virginia Tech is located on the western border of the city of Blacksburg. The UTM coordinates for the facility are 551.3 (horizontal) and 4120.6 (vertical). The Physical Plant is located on the northwest end of the Virginia Tech campus in the vicinity of commercial, academic and student dorm buildings (emphasis added). The Physical Plant has been in existence at this site for decades and is therefore considered suitable for installation of the proposed new boiler.

B. Project Summary

The university currently operates five boilers at the Physical Plant as described below:

On an annual average, over 90 percent of the steam produced by the physical plant is used for space heat. The remainder is used to generate electricity. Additional boiler capacity is needed to satisfv the increase in steam demand brought on by the recent construction at the University.

Virginia Tech initially applied for a permit to construct an additional coal-fired boiler in October 1991, proposing to reduce emissions from the existing facility in order to avoid tnggering the requirements for a federal Prevention of Significant Deterioration (PSD) permit. In July 1992 they decided not to accept limits on the existing facility, thus necessitating a PSD review. Following Virginia Tech's submittal of the required air quality analysis in April 1993, a public briefing was held in November 1993, followed by a public hearing in January 1994. In the course of addressing public comments, it was discovered that the stack parameters which had been supplied, and upon which the modeling results depended, were in error. Among the choices available, Virginia Tech has opted to decommission the existing No. 6 boiler prior to operating the proposed No. 11 boiler. Consequently, net emissions from this project do not trigger PSD requirements.

The proposed coal boiler (No. 11) has a heat input capacity of 146.7 * 10^6 Btu/hr. This is equivalent to a fuel feed rate of 5.54 tons of coal per hour, based on an average coal heating value of 13,250 Btu/lb. Virginia Tech proposes to limit coal consumption to 17,850 tons per year, or the equivalent of 3224 hours per year at full load.

C. Schedule of Project

The present permit application was submitted on July 25, 1994, with subsequent submittals on August 11 and 18. Virginia Tech has indicated that the date by which they wish to begin installation of the proposed boiler is June 1995. The proposed start-up date is January 1998.

II. EMISSIONS EVALUATION FOR CRITERIA AND TOXIC POLLUTANTS

A. Critena Pollutants

Sulfur dioxide emmissions from the No. 11 Boiler are to be controlled by a hydrated lime injection system (spray dryer) in line with a baghouse. The spray dryer is required to achieve a minimum control efficiency of 92.0 percent. This equates to an emissions limit of 0.161 lbs SO2/lO^6 Btu when applied to a maximum of 1.4 percent sulfur coal. The SO2 removal requirement and emissions limit are enforced on a 30-day rolling average.

A baghouse is porposed for particulate emissions control. The University has obtained a particulate emissions guarantee of 0.020 lbs TSP/10^6 Btu and 0.018 lbs PM10/10^6 Btu from the boiler vendor.

NOx emmisions are minimized by a mass-feed stoker configuration having inherently low emissions, in conjunction with the low excess air/staged combustion (LEA/SC). The Unicersity has obtained a NOx emissions guarentee of ,32 lbs NOx/10^6 Btu from the boiler vendor. The NOx emissions limit is enforced on a 30-day rolling average.

Permitted emissions forom the No. 11 Boiler are Summarized below. VOC's and lead are not included since predicted emissions are less than 0.5 tons per year. Detailed calculations are given in Appendix A.

Past actual emissions from the NO.6 Boiler, based upon the average of reported coal use for 1992 and 1993, are summerized below. Detailed calculations are given in Appendix B.

B. Toxic Pollutants

In accordance withagency policy, no permit emission limits or modeling were required since the net emissions increase in all toxic pollutants was less than the exemption rate. Detailed calculations are given in Appendices A and B; exemption level are given in Appendix C.

III. REGULATORY REVIEW AND CONSIDERATIONS

The area is classified as attainment or unclassified for all pollutants.

Having emitted over 700 tons/yr of SO2 over the past two years, Virginia Tech is an existing major source. Thus any significant emissions increase is subject to PSD review. Removal of the existing #6 coal boiler results in nonsignificant net emissions increases, or net decreases, of the criteria pollutants. A comparison of emissions from this modification to the PSD significant emissions rates is given below.

As indicated in the table above, PSD review is not required. In response to concerns expressed during this and the previous (early 1994) public comment penods regarding emmisions beneath the PSD significance lcvcl, Condition 28 has been added to indicate that further PSD review may be required if any limitation on the capacity to enut a pollutant is relaxed.

The EPA New Source Perfonnance Standards (NSPS), Subpart Db apply. A copy of the regulation is attached to the draft permit.

Best Available Control Technology BACT Requirements and Emissions Limitations

A. Particulate MatterlVisible Emissions

Particulate matter and visible emissions limits are based on recent BACT determinations for coal-fired cogeneration boilers throughout the state. More specific discussion of these emissions limits can be found in the engineering analyses for these permits; see Hadson Power 14 - Buena Vista (Registration No. 21130).

The resulting TSP and PM-10 emissions rates are 0.020 and 0.018 lbs/106 Btu, respectively. Visible emissions are limited to 10 percent opacity, except during one six-minute period per hour in which visible emissions shall not exceed 20 percent.

More stringent particulate controls have been determined to be economically _feasible for utility boilers ranging in size from 350 to 4000 x 106 Btu/hr. Virginia Tech's #11 Boiler is smaller than this range, rated at 146.7 x 106 Btu/hr. Because of the economy of scale, it can be determined that if more stringent particulate emissions controls are economically infeasible for a utility boiler, they are also infeasible in this application.

B. SO2

Available SO2 controls include combustion of low sulfur coal and dry and wet scruWing processes. A review of the BACI/LAER Clearinghouse indicated that few boilers, all considerably larger than the proposed unit, were required to use coal with a sulfur content less than 1.4 percent. Virginia Tech also provided vendor inforrnation asserting that use of lower sulfilr coal is not cost effective, particularly as contractual specifications set only an upper limit, with some shipments actually having a sulfur content below that specified.

Wet scrubbing processes are the most stnngent means of SO2 control and are capable of achieving 94 to 96 percent SO2 removal. However, wet sclubbing technologies have recently been determined to be economically j,nfeasible for coal-fired utiliq boilers in the range of 350 to 400 x 106 Btu/hr (see the engineenng analyses for Hadson Power 14 - Buena Vista and Cogentnx - Dinwiddie). Again, by the economy of scale, wet scrubbing is also infeasible for the #1l Boiler.

Dry scrubbing processes provide the next most stringent level of SO2 control. Two levels of dry scrubbing have been considered in the control technology analysis - 92 and 90 percent removal. Both are considered technically feasible. An analysis of economic feasibility is provided on the next page.

Both control options meet the Department's general criteria for cost-effectheness and are considered economically feasible.

We are aware of no environmental concerns that would preclude the application of a more stringent level of dry scrubbing. Therefore, dry scrubbing to achieve 92 percent SO2 removal is selected as BACI . Virginia Tech proposes to use this technology in conjunction with combustion of 1.4 percent sulfur coal. The resultng SO2 emissions rate is 0.165 lbs/10^6 BTU.

C. NOx

Available NOx controls are categorized as follows;

• selective catalytic reduction (SCR)
• selective non catalytic reduction (SNCR)
• general low-NOx combustion, including low excess air/staged combustion (LEA/SC)

The mass-feed boiler design proposed by Virginia Tech has inherently lower NOx emissions than comparable boiler designs.

At the request of the department, Virginia Tech has performed and economic analysis of additional NOx control. Costs of both SNCR and SCR are given below:

• Assumed to be 5 percent of system capital cost
• Costs are for anhydrous ammonia @ $220/ton delivered to Blacksburg in the following amounts: SNCR to 0.16 lbs NOx/106 Btu: 1.29 mol NH3/mol NOx (as NO2), 36.1 tons/yr SCR to 0.10 lbs NOx/106 Btu: 0.82 mol NH3/mol NOx (as NO2), 23.0 tons/yr
• Electrical cost of $.06/kW-hr and electncal use requirements as follows: SNCR to 0.16 lbs NOx/106 Btu: 75 kW, 3230 hours/yr SCR to 0.10 lbs NOx/106 Btu: 95 kW, 3230 hours/yr
• Costs for compacting and encapsulating spent catalyst in concrete, shipping, and disposing of catalyst in a landfill at $1000/m3. Catalyst disposal rates are based on replacement of one-third of total catalyst volume per year
• Assuming a 3-year catalyst life as a maximum available vendor guarantee. The catalytic reactor is constructed in a 3-layer configuration. One layer (one-third) of the catalyst is replaced each year. First-time catalyst cost is $280,000 for approximately 4.5 m3 of catalyst delivered. Replacement cost is $280,000 x l/3 plus $10,000 per installation. .

To the best of our knowledge, these costs exceed the arnount spent for cnteria pollutant control in other attainment areas throughout the U. S. As a result, both SCR and SNCR are considered economically infeasible. Therefore, LEA/SC in conjunction with the mass-feed boiler design is selected as BACT. In response to public comments, this requirement has been added to the perrnit as Condition 6. The resulting NOx emissions rate is 0.32 lbs/106 Btu

D. CO and VOC

At present, high efficiency combustion is the only accepted method for control of CO and VOC from coal-fired boilers. It is the opinion of the Department that Virginia Tech will make every effort to minimize CO and VOC emissions. Low CO and VOC emissions indicate proper fuel utilization, which is of economic benefit to the university. For these reasons, high- efficiency combustion is sufficient as BACT. CO and VOC emissions limits are based on EIS emission factors for uncontrolled emissions from overfeed stoker boilers.

E. Lead

Emissions of lead are expected to be less than 0.5 tons/yr and below PSD significance levels. Pursuant to current agency policy, an emissions limit does not appear in the draft permit and a detailed BACT analysis has not been done. However, the particulate ernissions control (baghouse) will also control lead emissions from the boiler.

F. Toxic Pollutants

All toxic pollutant emissions occur as TSP or VOC. In our opinion, the BACr requirements for TSP and VOC are also sufficient for toxic pollutants.

IV. Compliance Determination

A. Continous Emissions Monitoring

NSPS Subpart Db requires monitoring for opacity, SO2 before and after the FGD system, and NOx. Each gaseous (SO2 and NOx) emissions monitor must be colocated with a CO2 or O2 moitior to measure dilution air. All monitoring is to be done in the breeching for the #11 Boiler prior to the common power house stack.

B. Emissions Testing

Stack emissions testing is required for TSP or PM-10 as arranged with the Roanoke Air Office. Performance testing for SO2 and NOx is to be done by the continuous emissions monitors. In response to concerns expressed during this and the previous (early 1994) public comment periods, the test methods used to detennine sulfur and ash content of the coal have also been specified in Condition 11.

C . Visible Emmisions Evaluation

Condition No. 13 of the draft permits and requires that a one (1) hour visual emissions evaluation (VEE) be performed concurrently with the initial performance test. Condition No. 16 allows the continuous opal ity monitonng system to be used in lieu of Test Method 9.

D. Record Keeping

Condition 24 of the draft perrnit requires that Virginia Tech maintain records documenting the yearly consumption of coal and the sulfur and ash content of each shipment to demonstrate compliance with Conditions 10 and 11.

V. PUBLIC PARTICIPATION

The Virginia Tech boiler stack has been the object of several citizen complaints about smoke. The previous PSD application received adverse media and citizen comments, leading to requests by citizeDs that this permit be subject to public comment. Consequently, a public briefing and public heanng were conducted by the department on November 1, 1994. In addition, the public comment penod was extended to November 15, 1994. The public hearing notice, opening statements, Virginia Register notice, DEQ response to comments, and revised draft pennit are attached.

VI. NOTIFICATION OF OTHER GOVERNMENT AGENCIES

A. Local Zoning

No zoning approvals are needed, as the draft permit constitutes a minor increase in all critena emissions and a minor modification to an existing source. In addition, Virginia Tech, as a land-grant university, does not fall under the junsdiction of any local government. Therefore, a Iocal governing body notification fonn was not required by the DEQ. However, this form was completed and supplied as part of Virginia Tech's application.

B. Federal Land Managers

Review of the draft permit by the National Park Service or the United States Department of Agriculture, Forest Service is not required. In accordance with the Memoranda of Understanding between the DEQ, the Shenandoah National Park, and the Jefferson National Forest, federal land managers request review of all permits within 10 kilometers and all major source permits within 100 kilometers of the Shenandoah National Park and the James River Face Wilderness. The proposed boiler is located approximately 91 lcilometers fiom the southwest edge of the James River Face Wilderness.

VII. POLLUTION PREVENTION

No pollution prevention opportunities have been identified in conjunction with the proposed modification.

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