BENZENE EMISSIONS CONTROL FOR AREA SOURCES TRIETHYLENE GLYCOL DEHYDRATORS ABSTRACT

Transcription

1 BENZENE EMISSIONS CONTROL FOR AREA SOURCES TRIETHYLENE GLYCOL DEHYDRATORS G. H. Holliday, Ph.D., P.E., DEE Holliday Environmental Services, Inc. ABSTRACT On 8 July 2005 at 70 FR 39411, EPA proposed a revision to the 1998 proposed Hazardous Air Pollutant (HAP) controls for Area Sources (40 CFR Subpart 63 HH). The proposed rule applies to triethylene glycol (TEG) dehydrators having a through put 3 MMSCF/D or emitting 1 ton of benzene per year (tpy). Non-TEG dehydrators and TEG dehydrators having a throughput <3 MMSCF/D or <1 tpy are exempt from control under 40 CFR Subpart 63 HH. Operators of TEG dehydrators must install controls reducing benzene emissions 1) by at least 95 percent or 2) to outlet concentration 20 ml/l or 3) to 1 tpy. Unfortunately, the regulation as published is so complex as to preclude independent operator comments. In addition, the economic impact analysis is based on the number of Gas Processing Plant in existence in The EPA contractor who prepared the input data regarding the population of TEG dehydrators offers no support for correlating the number of TEG area source dehydrators with the number of Gas Processing Plant. The proposed rule as published is complex to the point small independent E&P operators are precluded from commenting, because the instant proposal must be combined with 1998 proposal resulting a proposed rule 233 typewritten pages long. Most small independent operators do not have access to the previous proposals. 1

2 BACKGROUND The Clean Air Act, Section 112(a) divides sources of Hazardous Air Pollutants (HAP) into Major Sources ( 10 tpy for any one HAP and 25 tpy for any combination of HAPs) and area sources, which are all sources not classed as major sources. EPA promulgated final rules for the control of major sources on 16 March 1994 (59 FR 1230). These rules have been amended since then. EPA published proposed rules for major and area sources 6 February 1998 (63 FR 6288) and amended 40 CFR Subpart 63 HH 17 June 1999 (64 FR 32628) and 29 June 2001 (66 FR 34551) for major sources. EPA did not promulgate the area source rules. On 8 July 2005, EPA modified the 1998 proposed rule for area sources located at oil and natural gas production facilities. The 8 July 2005 rule singles out Exploration and Production (E&P) remote dehydration facilities for control. All area sources having a through put 3MMSCF/D, or emitting 1 ton per year of benzene are subject to the controls proposed for 40 CFR Subpart 63 HH. The proposed rule, 40 CFR Subpart 63 HH (70 FR 39441), is complex. In addition, the preamble statements and the rule as proposed are not compatible. For example, at 70 FR 39445, col. 2, EPA discusses Option 2 rural and urban dehydrators controls based on year 2010 or later decennial census as being required to comply with the rules at the time the EPA publishes the updated listing of urban areas. No such requirement is included in the proposed rule (70 FR ). Thus, the preamble provides the reader with incorrect information. EPA ECONOMIC IMPACT ANALYSIS The EPA Economic Impact Analysis is based on a number of assumptions, which EPA does not supported in the documents contained in proposed rule, Docket A or OAR TEG Dehydrator Population Estimate The EPA Economic Impact Analysis is based on a number of assumptions, which are not supported by the proposed rule, references, discussion or logic. First, the EPA contractor relies on the 1996 discussion with representatives of the American Petroleum Institute (API) for the number of wells having specified gas production ranges (Docket A-94-04, Item 11-E-11, May 2, 1996). API represents major operators, who typically find small gas sources uneconomical. Accordingly, estimates may be biased. Our discussions with representatives of Railroad Commission of Texas show Texas does not routinely record statistics comparing the number of gas wells as a function of production rate. These statistics are available upon request for a fee. EPA nor E C/R (the EPA contractor) indicate they contracted for such statistics. In addition, it is doubtful, if API contracted with 33 State Agencies to prepare the data (E C/R Corporation, 2005). Second, the area source TEG dehydrator statistics are derived from the number of Gas Processing Plants estimated to exist in E C/R provides no support for assuming a correlation between gas plants and TEG area sources. When we asked the Railroad Commission 2

3 of Texas representative if such a correlation existed, he indicated the Commission had no data to support such an assumption. Third, E C/R made no attempt to provide insight into the how the TEG/Gas Plant correlation was accomplished. E C/R memoranda say TEG Model Plant A represents Area Sources, which include estimated area sources having throughput from 1 5 MMSCF/D. On 25 June 2005, EC/R (2005b) provided without support a table of Area Source TEG Dehydration Units by throughput from 0.1 to 5 MMSCF/D. E C/R attributed the total number of TEG dehydration Units (38,067) to EPA even though E C/R offered the estimated to EPA in their 15 June 2005 memorandum (E C/R, 2005a). We doubt if the attribution gave the estimate more authority. The estimate shown by E C/R for TEG dehydrators for the U.S. is about the same number as Texas records show for all E&P dehydrators in Texas in the range of 1-5 MMSCF/D (Personal Communication with Railroad Commission of Texas engineers). Not all E&P dehydrators use TEG, but with 32 other gas producing states, the EC/R estimate appears low. EC/R (2005b) quotes EPA (EPA-453/R a) as stating 10 percent of the TEG dehydrators would use flash tanks. A review of the EPA report (EPA-435/R a) does not reveal an EPA recommendation to use the 10 percent flash tank estimated, but simply suggests if 10 percent is used, the results are as. Such statements are misrepresentations of the facts and cast doubts on the rule making process. We have no argument with the calculations of estimated emissions based on the GRI-GLYCalc program, which was carefully validated by comparison with field measurements. However combining the GLYCalc results with an unsupported population of TEG dehydrators appears questionable. Cost Impact TEG area source dehydrator population is in question because of the lack of supported offered by E C/R in their analyses (E C/R, 2005 a and b). Accordingly, any cost/benefit analysis based on these population estimates is in question. We have attempted to obtain TEG dehydrator population data without success. The Independent Producers Association of America (IPAA) collects no such data. The American Petroleum Institute (API) does not collect these data. Discussions with representatives of the Railroad Commission of Texas demonstrate they have no means of distinguishing TEG dehydrators, regardless of throughput capacity. The above factors bring into sharp question the validity of the EPA cost/benefit analysis. Complex Proposal Many TEG dehydrators are owned by small independent E&P operators. EPA effectively precludes comments from those operators most affected by publishing only the supplemental information (70 FR ). Publishing only the supplemental information requires the commenter to obtain 40 CFR Subpart 63 HH as promulgated and cut and paste the supplemental proposed paragraphs into the previously proposed document. Such a task is daunting for an experienced person, but an impossible task for an independent E&P operator who is not subject to the major source rule and thus does not have ready access to the rule.. EPA has precluded many comments by imposing this daunting task. 3

4 To make matters worse, EPA at 70 FR 39452, col. 1&2, offers two options for area source control implementation when an area sources is updated from rural to urban 1 or urban 2 status. The proposed rule preamble at 70 FR makes reference to using census data from 2010 and later as a criterion for the conversion of rural to urban dehydrators. This increases the difficulty of understanding the proposed rule. General Standards GENERAL RULE CONTENT EPA requires all operators of TEG dehydrator, treating 3 MMSCF/D or emitting 1 tpy of benzene to 1) install emission controls 2) monitor for leaks of vent systems or 3) continuously (at least 75% of the time) monitor parametrically the control performance and 4) keep for 12 months records on site or accessible within 2 hours of the dehydrator. All records must be retained for four years. If monitor fails, operator must keep records showing if the startup, shutdown or malfunction plan was followed. In much of the Rocky Mountain region, winter prevents access to the well site. In this case access to record in the office is not possible within two hours Rural Options EPA presents the possibility of treating TEG dehydrators in rural and urban areas differently by means of Options 1 and 2 (70 FR 39452, col. 1 & 2). Option 1 is more favorable to operators. Option 2 presents a technically correct method of dealing with rural areas as they mature into urban areas with time, but imposes more severe time constraints. In effect, Option 2 mandates the 1) pre 6 February 1998 rural area sources comply with 40 CFR Subpart 63 HH within 3 years of publication of the rule, 2) pre 6 February 1998 area sources which later become rural as the result of census update comply with 40 CFR Subpart 63 HH within 3 years of publication of the census update and 3) post 5 February 1998 rural area source comply with 40 CFR Subpart 63 HH upon publication of the rule. This most likely will result in many post 5 February 1998 facilities being forces to shut in while locating and installing controls. DISCUSSION EPA succeeded, by publishing 40 CFR Subpart 63 HH as a very complicated supplement, in precluding comments from independent E&P operators. The supplement can not be read as a single document, because of the proliferation of references and cross-references to other paragraphs in 40 CFR Subpart 63 HH. When the supplement is combined with the referenced portions of existing Subpart 63 HH, the single column 12 point font document totals 233 pages. The resulting complication is unbelievable difficult to understand, since the area source supplement relies on the major source rule for many control requirements. The Agency and industry task of informing small operators of the existence of the rule will be a major obstacle in implementing the area source rule. Further, most small operators will 4

5 not be able to understand 40 CFR Subpart 63 HH, because of the complexity. Appalachian operators, who have a TEG dehydrator per 1000-foot deep well, will be crippled by the rule, since maintenance of the monitoring equipment will be beyond the capability of the contract lease operators. The Agency has had seven years to develop the area source rule. In that time, EPA should have recognized the complexity of the rule and sought to simplify the presentation and controls. EPA (70 FR 39448, col 1) reports the results of a 1998 economic analysis of the then proposed rule. Further, EPA admits they do not know what controls, if any, operators will employ in achieving compliance. EPA, without support or justification, assumes 90 percent of operators will use condensers and 10 percent will use flare to achieve compliance. Proposed rule Table 3 (70 FR 39447) summarizes the economic impact of the rule using Option 1 as $39.2 million /year. EPA does not indicate if these costs are the 1998 or 2005 estimates. Further. If Table 3 presents the 2005 estimate of affected facility, the estimate must be low, because in 2005 there were about 1000 glycol dehydrators located in Texas alone having more than 3 MMSCF/D throughput. When the other thirty-two producing States are considered, there must be more than 2200 TEG dehydration facilities affected by the proposed rule 40 CFR Subpart 63 HH. CONCLUSIONS The TEG dehydrator area source proposed rule 40 CFR Subpart 63 HH precludes meaningful comment by small operators, because it is too complicated for small independent operators to comprehend. The economic impact analysis appears low-based on the number of dehydrators located in Texas. The proposed rule cost benefit assumptions a not sufficiently documented to support the proposed rule. RECOMMENDATIONS Withdraw the proposed rule 40 CFR Subpart 63 HH for area sources. Prepare an understandable rule dealing only with area sources. Prepare an accurate estimate of the cost of the rule. REFERENCES E C/R Incorporated, 2005a. Memorandum from Heather P. Brown to Guy Nizick, EPA/OAQPS/ESD/WCPG. Methodology for Estimating the Number of Area Sources in Oil and Natural Gas Production Source Category. June 15 5

6 E C/R Incorporated, 2005b, Memorandum from Heather P. Brown to Guy Nizick, EPA/OAQPS/ESD/WCPG. Revised Impact for Area Sources in Oil and Natural Gas Production Source Category. 25 June EPA, National Emission Standards for Hazardous Air Pollutants for Source Catagories: Oil and Natural Gas Production and Natural Gas Transmission and Storage Background Information Document for Proposed Standards, EPA-453/R a. 6