Comment submitted by James Jarrett
AnonymousOtherIndividual
Summary: The commenter provides technical feedback and data comparisons regarding the inclusion of methanol in NESHAP subpart HHH and the use of the ProMax model for emissions calculations. They suggest specific monitoring requirements, such as adding methanol to wet gas samples and considering reboiler temperature monitoring, based on their own simulation results.
Page 21686. In the absence of clear information to verify that methanol is emitted from natural gas transmission and storage facilities, we are not proposing to amend table 1 in NESHAP subpart HHH to add methanol.
Comment: If clear information is not received could HHH specify that when inlet wet gas samples are taken that methanol be added for analysis? I doubt it would add much cost to the analysis. The time of year the sample is taken may also affect the results since I understand that methanol is used for freeze protection. Am I correct that if there is no emission standard in HHH then major source HAP emission thresholds would still apply that would limit methanol emissions to less than 10 tons per year for the facility to be considered a non-major source? The revised Subpart HHH could have the company report methanol results and emissions estimate in an annual report to demonstrate if the facility is a major source for methanol. I have not seen any methanol analysis because companies have not been required to include methanol in the inlet wet gas analysis.
Page 21699. The EPA has approved the use of the ProMax model as suitable for performing the emissions and related parameter determinations for which the GLYCalc model is already allowed in subpart HH and may be used as an alternative to the GLYCalc model under a list of stipulated conditions.
Comment: I used ProMax 6.0 and GLYCalc 4.0 to compare identical inputs (see attached). ProMax VOC estimate was about +28% higher and the benzene was about -13% lower in this simulation. ProMax demonstrates that as reboiler operating temperature increase or decrease that the regenerator still vent VOC/HAP emissions also increase and decrease. GLYCalc does not have this option. Comparisons between GLYCalc and ProMax are attached where the reboiler temperature changes in increments of 10 degrees Fahrenheit. The main change in lower reboiler temperature is the dry gas water content. In this simulation, it goes from 2.53 lbs H2O/MMscf with the reboiler operating at 410 F to 5.22 lbs H2O/MMscf with the reboiler operating at 350 F. Based on this data should reboiler temperature monitoring be added to HH and HHH?