§ 63.500Back-end process provisions—carbon disulfide limitations for styrene butadiene rubber by emulsion processes.
(a) Owners or operators of sources subject to this subpart producing styrene butadiene rubber using an emulsion process shall operate the process such that the carbon disulfide concentration in each crumb dryer exhausts shall not exceed 45 ppmv.
(1) The owner or operator shall develop standard operating procedures for the addition of sulfur containing shortstop agents to ensure that the limitation in paragraph (a) of this section is maintained. There shall be a standard operating procedure representing the production of every grade of styrene butadiene rubber produced at the affected source using a sulfur containing shortstop agent.
(2) A validation of each standard operating procedure shall be conducted in accordance with paragraph (c) of this section, except as provided in paragraph (b) of this section, to demonstrate compliance with the limitation in paragraph (a) of this section.
(3) The owner or operator shall operate the process in accordance with a validated standard operating procedure at all times when styrene butadiene rubber is being produced using a sulfur containing shortstop agent. If a standard operating procedure is changed, it shall be re-validated.
(4) Records specified in paragraph (d) of this section shall be maintained.
(5) Reports shall be submitted in accordance with paragraph (e) of this section.
(b) Crumb dryers that are vented to a combustion device are not subject to the provisions in this section.
(c) The owner or operator shall validate each standard operating procedure to determine compliance with the limitation in paragraph (a) of this section using the testing procedures in paragraph (c)(1) of this section or engineering assessment, as described in paragraph (c)(2) of this section.
(1) The owner or operator may choose to conduct a performance test, using the procedures in paragraphs (c)(1)(i) through (c)(1)(iii) of this section to demonstrate compliance with the carbon disulfide concentration limitation in paragraph (a) of this section. One test shall be conducted for each standard operating procedure.
(i) Method 1 or 1A of 40 CFR part 60, appendix A, as required, shall be used for selection of the sampling sites.
(ii) The gas volumetric flow rate shall be determined using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A, as required.
(iii) To determine compliance with the carbon disulfide concentration limit in paragraph (a) of this section, the owner or operator shall use Method 18 or Method 25A of 40 CFR part 60, appendix A to measure carbon disulfide. Alternatively, any other method or data that has been validated according to the applicable procedures in Method 301, 40 CFR part 63, appendix A, may be used. The following procedures shall be used to calculate carbon disulfide concentration:
(A) The minimum sampling time for each run shall be 1 hour, in which either an integrated sample or a minimum of four grab samples shall be taken. If grab sampling is used, then the samples shall be taken at approximately equal intervals in time, such as 15 minute intervals during the run.
(B) The concentration of carbon disulfide shall be calculated using Equation 32.
CCS2=Concentration of carbon disulfide, dry basis, ppmv.
CCS2i=Concentration of carbon disulfide of sample i, dry basis, ppmv.
n=Number of samples in the sample run.
(2) The owner or operator may use engineering assessment to demonstrate compliance with the carbon disulfide concentration limitation in paragraph (a) of this section. Engineering assessment includes, but is not limited to, the following:
(i) Previous test results, provided the tests are representative of current operating practices at the process unit.
(ii) Bench-scale or pilot-scale test data representative of the process under representative operating conditions.
(iii) Flow rate and/or carbon disulfide emission rate specified or implied within an applicable permit limit.
(iv) Design analysis based on accepted chemical engineering principles, measurable process parameters, or physical or chemical laws or properties. Examples of analytical methods include, but are not limited to:
(A) Use of material balances,
(B) Estimation of flow rate based on physical equipment design such as pump or blower capacities, and
(C) Estimation of carbon disulfide concentrations based on saturation conditions.
(v) All data, assumptions, and procedures used in the engineering assessment shall be documented.
(d) Owners and operators of sources subject to this section shall maintain the records specified in paragraphs (d)(1) and (d)(2) of this section.
(1) Documentation of the results of the testing required by paragraph (c) of this section.
(2) A description of the standard operating procedure used during the testing. This description shall include, at a minimum, an identification of the sulfur containing shortstop agent added to the styrene butadiene rubber prior to the dryers, an identification of the point and time in the process where the sulfur containing shortstop agent is added, and an identification of the amount of sulfur containing shortstop agent added per unit of latex.
(e) Owners and operators shall submit the reports as specified in paragraphs (e)(1) and (e)(2) of this section.
(1) As part of the Notification of Compliance Status specified in § 63.506(e)(5), documentation of the results of the testing required by paragraph (c) of this section.
(2) If changes are made in the standard operating procedure used during the compliance test and recorded in accordance with paragraph (d)(2) of this section, and if those changes have the potential for increasing the concentration of carbon disulfide in the crumb dryer exhaust to above the 45 ppmv limit, the owner or operator shall:
(i) Redetermine compliance using the test procedures in paragraph (c) of this section, and
(ii) Submit documentation of the testing results in the next periodic report required by § 63.506(e)(6).