Liquid release

API Publ 340, Liquid Release Prevention and Detection Measures for Aboveground Storage Facilities, October 1997. 

Gas-liquid Released gas (air) bubbles rising in a large tank Mist formation from LPG evaporation Splash filling Cleaning with wet steam Mist formation from high pressure water jets... 

Where a PR valve on a fractionator is used to protect a distillate drum with submerged inlet, the PR valve must be located on the tower itself, rather than on the overhead piping, or it must be discharged to a closed system. This is to preclude liquid release, should the PR valve discharge under fire conditions at the distillate drum. 

When applying low temperature requirements, one should consider safety valve and flare headers to be subject to "shock chilling" if they can be exposed to cold liquids released into the system. This includes flare headers from blowdown drums into which cold liquids are discharged. Where laterals of different piping material are combined, the material of the lower-temperature header is continued for the rest of the combined line, and is also extended back into the other lines for 6 m. 

The source-term models consist of gas release from a reservoir, a liquid release from a... 

For a nonflashing liquid release, the material in the cloud equals ... 

Liquids under pressure (pipeline leaks, pump seal failures, etc.), will be thrown some distance from the point source, while atmospheric leakages will emit at the point of release. The other characteristic of liquid releases is their flash points. High flash point liquids, not operating above their flash point temperatures, are inherently safer than low flash point liquids. Most liquid fires are relatively easy to contain and suppress while gas fires are prone to explosion possibilities if extinguished and source points are not isolated. 

Hydrocarbon materials must first be in a vapor condition before combustion processes can occur. For any gaseous material this is an inherent property. Liquids however must have significant vapor emissions in order for flammable concentrations to be present for combustion processes to occur. Therefore hydrocarbon liquid releases are nominally less dangerous than a gas release. 

The primary features of a flare are safety and reliability, while the primary objective of the flare is to prevent the release of any unburned gases. In reviewing existing facilities worldwide, from Russia to South America, onshore and offshore, most installations have admitted either officially or unofficially that on occasion, a liquid release has occurred from the tip of the flare stack. This has occurred even with the installation of a flare header liquid knock out drum. In most cases this has caused no apparent problems although in a few... 

Where relief valves are provided on liquid storage tanks or vessels, where there is a possibility of liquid release, i.e., liquid slug, careful evaluation of the release disposal system (e.g., flare header) needs to be undertaken. In some cases, a liquid slug may block a header from releasing pressure and defeat the purpose of the pressure release system. 

Riddle, H.S., Riddle, S.W., Rasmussen, L.E.L. and Goodwin, T.E. (2000) The first disclosure and preliminary investigation of a liquid released from the ears of African elephants. Zoo Biol. 19, 475—480. 

Figures 5-3 and 5-4 illustrate the potential outcomes of a gas and liquid release, respectively (CCPS, 2000). Unconfined vapor cloud explosions...

Figure 5-4. Event Tree for Flammable Liquid Release...

If the release is the result of a major spill and there is immediate ignition, the result is usually a pool fire. In an unignited liquid release, the spill will be... 

Spacing between plant units is important in limiting damage from fires, explosions and gaseous or liquid releases. Proper spacing also provides adequate access for repair and emergency equipment as well as for evacuation in the case of accidents. 

For this purpose, we developed a modified dynamic headspace technique for the analysis of truffle flesh and the aromatic liquid released during cooking. 

Modify the process to reduce the consequences of a release for example, use refrigerated rather than pressurized storage, which results in higher liquid release and lower vapor release rates (from the same hole size) and lower vapor generation rates from a pool dilute hazardous materials with inert or less hazardous material to reduce partial pressure or reduce operating pressures to reduce release rates. 

A liquid release offers the potential for the formation of an aerosol (mist). Aerosol formation is influenced by mechanical force (acceleration) and fluid properties, such as the material s surface tension. Additionally, in some systems the pressure, because of static head, may be adequate to cause some aerosol formation and must be considered. Examples of liquid releases include an accidentally opened storage tank drain valve, a pipeline failure downstream of a pump, a damaged nozzle at the base of a liquid knockout drum, or the failure of a loading hose. 

Figure 2.3. Typical liquid release event tree.

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