(65c) The Fire Hazard of An Ethanol Process Facility

There has been a recent rise in the demand for commercial-grade ethanol largely due to its increased use as a fuel additive or alternative fuel source for automobiles. This has resulted in the construction of many new process facilities both internationally and domestically. The level of fire protection at these facilities varies substantially depending on the access to a local water supply, design of the facility, and the facility output.

A methodology was developed to evaluate the maximum hazard posed to the structure of a process facility due to a large flammable liquid pool fire. The hazard evaluation was based on the vertical heat flux profile, which was measured with specially designed instrumentation based on the plate thermometer concept. Testing focused on ethanol, which produced a maximum net heat flux of ~140 kW/m². Though somewhat lower than the corresponding value for a heptane fire of ~180 kW/m², ethanol still represents a severe hazard.

The effectiveness of various water based fire protection schemes was then evaluated on the relative reduction in the measured heat flux. Several sprinkler system designs were shown to provide acceptable protection of a process structure, while local area water spray systems are needed to protect objects near the pool fire surface, such as the base of the structural columns or sensitive equipment. In addition, several sprinkler and water spray protection system designs common to the industry were further shown to be inadequate to reduce the hazard below an acceptable level.