40 CFR 63.2164 - If I monitor brew ethanol, what are my monitoring installation, operation, and maintenance requirements?
(b) Each of your brew ethanol monitors must complete a minimum of one cycle of operation (sampling, analyzing, and data recording) for each successive 30-minute period within each batch monitoring period. Except as specified in paragraph (c) of this section, you must have a minimum of two cycles of operation in a 1-hour period to have a valid hour of data.
(c) You must reduce the brew ethanol monitor data to arithmetic batch averages computed from two or more data points over each 1-hour period, except during periods when calibration, quality assurance, or maintenance activities pursuant to provisions of this part are being performed. During these periods, a valid hour of data must consist of at least one data point representing a 30-minute period.
(e) You must set the brew ethanol monitor span to correspond to not greater than 5 times the relevant emission limitation; note that we consider 1.5 to 2.5 times the relevant emission limitation to be the optimum range, in general. You must use the brew-to-exhaust correlation equation established under § 63.2161(f) to determine the span value for your brew ethanol monitor that corresponds to the relevant emission limitation.
(f) For each brew ethanol monitor, you must record the results of each inspection, calibration, and validation check.
(1) You must calibrate the GC at least daily, by analyzing standard solutions of ethanol in water (0.05 percent, 0.15 percent, and 0.3 percent).
(2) For use in calibrating the GC, you must prepare the standard solutions of ethanol using the procedures listed in paragraphs (g)(2)(i) through (vi) of this section.
(i) Starting with 100-percent ethanol, you must dry the ethanol by adding a small amount of anhydrous magnesium sulfate (granular) to 15-20 milliliters (ml) of ethanol.
(ii) You must place approximately 50 ml of water into a 100-ml volumetric flask and place the flask on a balance. You must tare the balance. You must weigh 2.3670 grams of the dry (anhydrous) ethanol into the volumetric flask.
(iii) You must add the 100-ml volumetric flask contents to a 1000-ml volumetric flask. You must rinse the 100-ml volumetric flask with water into the 1000-ml flask. You must bring the volume to 1000 ml with water.
(iv) You must place an aliquot into a sample bottle labeled “0.3% Ethanol.”
(v) You must fill a 50-ml volumetric flask from the contents of the 1000-ml flask. You must add the contents of the 50-ml volumetric flask to a 100-ml volumetric flask and rinse the 50-ml flask into the 100-ml flask with water. You must bring the volume to 100 ml with water. You must place the contents into a sample bottle labeled “0.15% Ethanol.”
(vi) With a 10-ml volumetric pipette, you must add two 10.0-ml volumes of water to a sample bottle labeled “0.05% Ethanol.” With a 10.0-ml volumetric pipette, you must pipette 10.0 ml of the 0.15 percent ethanol solution into the sample bottle labeled “0.05% Ethanol.”
(3) For use in calibrating the GC, you must dispense samples of the standard solutions of ethanol in water in aliquots to appropriately labeled and dated glass sample bottles fitted with caps having a Teflon® seal. You may keep refrigerated samples unopened for 1 month. You must prepare new calibration standards of ethanol in water at least monthly.
(h) You must calibrate the brew ethanol monitor according to paragraphs (h)(1) through (3) of this section.
(1) To calibrate the brew ethanol monitor, you must inject a brew sample into a calibrated GC and compare the simultaneous ethanol value given by the brew ethanol monitor to that given by the GC. You must use either the Porapak® Q, 80-100 mesh, 6′ x 1/8″, stainless steel packed column; or the DB Wax, 0.53 millimeter x 30 meter capillary column.
(2) If a brew ethanol monitor value for ethanol differs by 20 percent or more from the corresponding GC ethanol value, you must determine the brew ethanol values throughout the rest of the batch monitoring period by injecting brew samples into the GC not less frequently than once every 30 minutes. From the time at which you detect a difference of 20 percent or more until the batch monitoring period ends, the GC data will serve as the brew ethanol monitor data.