Project SynopsisPerform site inspections, calculations, and process modeling to evaluate multiple cold ammonia storage facility flare systems, estimate releases, and provide improvement recommendations.
COLD AMMONIA STORAGE TERMINALS FLARE EMISSIONS MODELING
The client owns and operates anhydrous ammonia (NH3NH3) cold (cryogenic) storage facilities. Process Engineering Associates, LLC (PROCESS) was contracted by the client to develop a tool for each selected facility to help estimate emissions from the cold ammonia storage tank to the flare when the compressors in the associated ammonia refrigeration system shut down. In addition, PROCESS was contracted to perform an evaluation of the flare at each facility to help ensure that all required parameters of the New Source Performance Standard (NSPS) for flaring (40 CFR 60.18) are met in order to assume a minimum destruction efficiency at the flare of 98%. Specific project tasks for each facility included the following:
- Development of a comprehensive Excel-based heat transfer model designed to predict product vaporization rates from the cryogenic storage tanks during refrigeration system shutdown periods given site-specific tank and system data and local ambient condition ranges. PROCESS also developed site-specific operations manuals such that client engineering and operations personnel can use the program.
- Development of a hydraulic model of the flare system using commercial process simulation software. The hydraulic model accounts for heat transfer between the atmosphere and the contents of the flare piping during the worst-case flaring event to estimate the maximum velocity in the flare stack.
- Execution of a flare system evaluation to determine if the flare system meets operating regulations and guidelines as specified in NSPS 40 CFR 60.18. Recommendations were made for design or control system changes to improve the flare system operation as necessary.
As part of this project, a project team member visited each cold storage facility for the purpose of collecting the information required for evaluation of the flare systems and for development of the emissions calculation programs. A total of six (6) facilities were included in the study.
- Pipeline Cryogenic Storage Facilities
- Regulatory compliance emissions calculations
- Flare systems modeling, evaluation, and improvements