Empty vessel purging.
Empty vessel purging. You must calculate emissions from empty vessel purging using Equation 15 of this section (Note: The term e-Ft/v can be assumed to be 0):
(i) Engineering assessments. You must conduct an engineering assessment to calculate HAP emissions or emission episodes from each process vent that are not due to vapor displacement, partially filled vessel purging, heating, depressurization, vacuum operations, gas evolution, air drying or empty vessel purging. An engineering assessment may also be used to support a finding that the emissions estimation equations in this section are inappropriate. All data, assumptions and procedures used in the engineering assessment must be documented, are subject to preapproval by the Administrator, and must be reported in the batch precompliance report. An engineering assessment should include, but is not limited to, the items listed in paragraphs (i)(1) through (4) of this section.
(1) Previous test results provided the tests are representative of current operating practices at the process unit.
(2) Bench-scale or pilot-scale test data representative of the process under representative operating conditions.
(3) Maximum flow rate, HAP emission rate, concentration, or other relevant parameter specified or implied within a permit limit applicable to the process vent.
(4) 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 the following:
(i) Use of material balances based on process stoichiometry to estimate maximum organic HAP concentrations.
(ii) Estimation of maximum flow rate based on physical equipment design such as pump or blower capacities.
(iii) Estimation of HAP concentrations based on saturation conditions.