Perform a safe discharge evaluation and sizing review for a set of existing pressure safety valves in a large grain ethanol production facility.
EVALUATION OF SAFE ATMOSPHERIC DISCHARGE FOR EXISTING PSVs
Process Engineering Associates, LLC (PROCESS) was contracted by the client, an ethanol production facility, to evaluate twelve (12) existing pressure safety valves (PSVs) in the distillation area at one of their facilities in the Midwest U.S. for safe atmospheric relief. This evaluation included both a qualitative and, as required, quantitative safety screening of each valve to define acceptable relief guidelines for venting. The following tasks were performed:
Qualitative screening of valves which involved review of the existing PSV sizing calculations and existing PHA report/recommendations to classify each valve into one of the following categories based on the nature of the fluid discharged:
- Relief devices (such as low pressure steam or thermal cooling water relief devices) that simply need to be piped so that discharge does not have the potential to impinge personnel in its path or inhibit an operator from performing a function in an emergency.
- Relief devices that may have a slightly higher level of safety concerns such as the release of an asphyxiate, or a saturated vapor that may condense, etc.
- Relief devices that require some quantitative analysis and more detailed calculations (exit velocity vs. wind speed, temperature, etc.) in order to generate a relief guideline. Such devices would involve flammable vapors, toxic vapors, vapors heavier than air (e.g., CO2), etc.
- Relief devices that are special cases, e.g., they have been sized for vapor release but may have situations that could release flammable liquid, 2-phase mixtures, or solids. These require special design considerations.
- Defined acceptable relief guidelines involving performing the necessary quantitative calculations to define the acceptable relief guideline for each valve
- Updated existing relief device calculations to validate the correct sizing of new piping configurations based on the acceptable relief guidelines
- Generated a short summary report that included relief device sizing information and all backup calculations and documentation.
- Grain Ethanol Fuels Production
- Safety valve evaluation
- Operational process hazards mitigation