Project Synopsis

Provide process engineering assistance with the Maintenance, Startup, & Shutdown (MSS) emission calculations for the air permit application of a new gasification plant using state and EPA methodologies.

Project Summary


The client owns and operates a major chemical manufacturing facility that produces organic specialty and non-specialty chemical products.  Process Engineering Associates, LLC (PROCESS) was contracted by the client to assist with the Maintenance, Startup, & Shutdown (MSS) emission calculations for the air permit application of a new gasification plant.  Calculations followed the state specific Commission on Environmental Quality (CEQ) guidelines for the state in which the plant is to be built, which use standardized EPA-approved methodologies.

More specifically, PROCESS was asked to complete the maintenance section of the MSS emission calculations for the Sulfur Recovery Unit (SRU), Tail Gas Treatment Unit (TGTU), and Sour Water Stripper (SWS).  This required working with operators running a similar existing plant to establish the current maintenance procedures used and determine how the new plant will operate differently.  However, numerous assumptions still had to be made and documented to calculate emission values that were conservative enough that the plant will not exceed these numbers once it is built and operating but low enough so that the permit application is accepted.

PROCESS completed the following tasks in support of the MSS emission calculations:

  • Identifying all emission-producing maintenance activities for the SRU, TGTU, and SWS
  • Working with the client to determine calculation methods that follow CEQ guidelines for each emission-producing maintenance activity and developing spreadsheets to be used for these calculations
  • Generating the emissions calculations using the developed spreadsheets and documenting all assumptions
  • Meeting with operators several times to review maintenance procedures and assumptions used to calculate the emission rates
  • Developing sample calculations which will be used by CEQ to approve the calculation methods used to determine the emissions for each maintenance activity. PROCESS developed the sample calculations for Loading Catalyst, Vessel Filling, and Opening Vessel after Purging (Gas Only)

A total of 113 calculations for emission-producing maintenance activities were completed by PROCESS during this project.  The following is a list of the types of calculations performed:

  • Catalyst Handling
  • Process Gas Diverted to Incinerator
  • Vessel Purging to Incinerator (Gas Only)
  • Opening Vessel After Purging (Gas Only)
  • Pump Maintenance Emissions
  • Vessel Filling (Gases in Liquid)
  • Opening Wetted Vessels
  • Process Water Drained to WWT

Industry Type

  • Chemicals manufacturing
  • Gasification
  • Alternative Fuels

Utilized Skills

  • Predictive emissions calculations
  • New facility permitting assistance
  • Plant operations and maintenance knowledge

Contact Us