Liquid-filled vessels

Relief valves located on liquid-filled reflux drums can be a major safety problem depending on the design and size of the flare knockout (K.O.) drum. Some plants have giant flare K.O. drums with large capacity 

Overfilling a flare K.O. drum is a serious matter. Liquid hydrocarbons may erupt from the flare like a giant flame-thrower. My secretary ran out of the Good Hope Refinery without her shoes when our flare stack overflowed. Burning liquid butane erupting from the Amoco Oil flare in Whiting, Indiana, was reported as a missile laimch by a spy satellite. 

The ASME Boiler Code may require a liquid-filled vessel to have a pressure relief valve if it can be isolated from another vessel that has relief valve protection. Then the designer s obligation is to determine if the flare system can handle the volume of liquid depressuring through the relief valve on the liquid-filled vessel. 

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Set Pressure - The set pressure (the pressure at whieh the PR valve is designed to open) is speeified in accordance with Code requirements. In most vessel apphcations, the set pressure of at least one PR valve is equal to the design pressure. However, this set pressure is adjusted (up or down) for any effect of static pressure and friction pressure drop that may apply when the valve is installed elsewhere than directly on the vessel. For example, if a PR valve is installed in a non-flowing line above a liquid-filled vessel, the PR valve set pressure would be reduced sufficiently to allow for the liquid static head between the vessel and the valve. 

Description Liquid or gaseous ethylene is fed, together with a solvent and required comonomer(s) into a stirred, liquid-filled, vessel-type reactor (1). The reactor is operated adiabatically thus, the feed is precooled. All heat of reaction is used to raise polymerization temperature up to approximately 200°C. Hydrogen is used to control polymer molecular weight. A high-activity, proprietaiy catalyst is prepared onsite from commercially available components. Ethylene... 

Furthermore the effectiveness of condensation or absorption is influenced by the temperature of the fluid in the liquid filled vessel, its filling level, which influences the bubble rise time and the pressure. The latter should be as high as possible in accord with the requirements of the pressure relief device. 

Liquid-filled vessel Expansion of gas from vapor space volume ... 

The thionizer, which operates under slight pressure, is usually a tall empty vessel of much smaller diameter and a height of 120 ft. Air is supplied by compres.sors, and blown upward through the liquid filled vessel, lifting the sulfur particles to the top surface, where they form a froth. A somewhat different and shorter thionizer design featuring two concentric shells is reported by Powell (1936). 

L. L. Simpson, Fir exposure of liquid-filled vessels, Process Safety Progress, Vol. 22, No. 1, March 2003, p. 27-32. 

Corrosion is probably the greatest threat to vessel life. Partially filled vessels frequently have severe pitting at the liquid-vapor interface. Vessels usually do not have a corrosion allowance on the outside. Lack of protec tion against the weather or against the drip of corrosive chemicals can reduce vessel life. Insulation may contain damaging substances. Chlorides in insulating materials can cause cracking of stainless steels. 

For extraction, the mixing usually takes place either in a vessel which also serves as the settler (these can be baffled or unbaffled), or a separate mixing compartment (usually baffled if there is a gas-hquid interface, and usually unbaffled if it is liquid filled). 

Sudden cooling of a vapour-filled vessel which is sealed, or inadequately vented, may cause an implosion due to condensation to liquid. 

Vessels - All vessels and equipment which can be blocked in while liquid filled and subjected to subsequent heating and thermal expansion by any of the mechanisms described above, must be protected by any one of the methods described for protecting piping. 

A vessel filled with a pressurized, superheated liquid can produce blasts upon bursting in three ways. First, the vapor that is usually present above the liquid can generate a blast, as from a gas-filled vessel. Second, the liquid will boil upon depressurization, and, if rapid boiling occurs, a blast wiU result. Third, if the fluid is combustible and the BLEVE is not fire induced, a vapor cloud explosion may occur (see Section 4.3.3.). In this subsection, only the first and second types of blast wiU be investigated. 

The explosion of a vessel full of liquid above the superheat limit temperature has much more energy, and therefore, causes a much more severe blast than a gas- or vapor-filled vessel. 

Clearly, from Table 9.12, the more dangerous case not involving hashing liquid is the 10% filled vessel. 

Fauske, H. K, et al, Emergency Relief Vent Sizing for Fire Emergencies Invoking Liquid-Filled Atmospheric Storage Vessels, Plant/Operations Progress, 5 (4), 205-208, October 1986. 

Epstein, M., Fauske, H. K. and Hauser, G. M., The Onset of Two-Phase Venting Via Entr ainment in Liquid-Filled Storage Vessels Exposed to Fire, Journal Loss Prevention Process Industries, 2 (1), 45-49, January 1989. 

If the liquid is not volatile, the condensing reservoir shown is not required and the high and low pressure connections on the DP cell are reversed. The DP cell is normally located below the lower measuring point (or tapping) in the vessel. Any lines connected to the DP cell which are liquid filled should be bled through the DP cell bleed port to make sure that there is no trapped vapour present. 

To identify external fire scenarios, all equipment with a liquid inventory located in an area of the facility potentially subject to an external fire was selected. External fire protection was not considered for vapour-filled vessels,... 

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