Valves leakage

A refinery operation produces about 500,000 barrels of crude per year. There are approximately 1500 gate valves used in the operation. Develop an estimate of the potential hydrocarbon emissions resulting from valve leakage. What is this worth in terms of lost revenues to the facility You can find some information on typical valve leakage rates from searching on w w w. google. com. 

A reversible adiabatic process is known as isentropic. Thus, the two conditions are directly related. In actual practice compressors generate friction heat, give off heat, have valve leakage and have piston ring leakage. These deviations... 

Absence of pump head inlet and outlet check valves to ensure reliable 7/24 operation without check valve leakage and breakage... 

An example of how this Stage works is given for the precursor reactor valve leakage in company A. Graphically this analysis is shown in Appendix C. 

I could repeat the same story for the intake or suction valves. Leakage of the intake valves would appear as peaks on the compression portion of the cycle. Pulsation losses for the intake valves would appear as peaks on the indicator card during the suction or intake portion of the cycle. 

For some industrial cooling water applications, where process contamination is often an inherent problem, a high chlorine/low bromine ratio product may be preferable. This type of problem can happen, for example, where repeated hot/cold cycles are part of the process and some valve leakage and interchange of water between circuits may occur. Thus, the (lower cost) chlorine component is employed in satisfying the contaminant halogen demand and the bromine component (perhaps with some degree of Br recycle) subsequently acts as a biocide. 

While here the tail pipe has the right construction and orientation, it is unfortunately not equipped with a drain. Therefore dirt can accumulate and create excessive backpressure, and can enter the valve and damage the seat surface, causing valve leakage after operation. The size of the tail pipe at the connection is smaller than the valve outlet. This will provide excessive built-up backpressure. Again, these considerations must be taken into account when sizing the valve, as the valve may otherwise be undersized. ... 

Rupture disks are often used upstream of relief valves to protect the relief valve from corrosion or to reduce losses due to relief valve leakage. Large rupture disks are also used in situations that require very fast response time or high relieving load (for example, reactor runaway and external fire cases). They are also used in situations in which pressure is intentionally reduced below the operating pressure for safety reasons. 

Valve leakage A leak of one valve, for example in the gradient module, could disturb the elution profile. 

Answer by Author The flange pressures in the load decay test were in great excess of realistic values. Several specimens indicated that they had leveled out after 30 min. The curves were not corrected for check valve leakage in the hydraulic loading setup described. In an actual application, retightening of flanges may possibly be helpful, in light of the fact that essentially no compression set or creep is apparent. 

The level of protection that can be provided by a respirator is indicated by the respirator s protection factor (PF). This number, determined experimentally by measuring facepiece seal and exhalation valve leakage, indicates the relative difference in concentration of the concentrations of substances outside and inside the facepiece that can be maintained by the respirator. For example, a PF of 10 for a respirator means that a user could expect to inhale no more than one tenth of the airborne contaminant present. A source of protection factors for various types of atmosphere-supplying and air-purifying respirators can be found in the American National Standards Institute (ANSI) standard ANSI Z-88.2-1980. 

Specifications should insist that the maximum-allowed firing rate of a burner should be limited to 6 in. (151 mm) of water-column pressure drop across the bed when the excess air is above 15% as measured by flow devices on the air and fuel streams. The reason for 15% rather than 10% excess air is because of air and exhaust valve leakage. This leakage of combustion air cannot be used to burn fuel, but as long as the air loss is not greater than 10%, all the fuel can be burned in the furnace. 

POSSIBLE CAUSES Low fluid level Suction strainer blocked Oil overheated Air entrained in fluid Leakage past direction control valve Leakage past screenchanger cylinder Pump damaged/worn REMEDY A Fill reservoir A Clean or replace A See below A Allow bubbles to subside, use antifoam A Repair or replace A Repair or replace A Replace pump... 

If an actoator opens or closes with no closed actoators between it and either the inlet or the outlet, the transfer of fluid is made equally from or to both sides. Once the fluid volume is computed, the flow rate flows from the actuation frequency. Maximum head is taken to be the maximum pressure exerted by an actoator (though this is not often known), and efficiency is estimated from the actuation sequence. Often, an estimate of flow rate is all that is desired. It must be noted that these estimates are very coarse, with, for example, errors of a factor of two reported and attributed to unmodeled valve leakage [8]. 

USNRC RG 1.96 (June 1976) Design of main steam isolation valve leakage control systems for boiling water reactor nuclear power plants . USNRC RG 1.106 (March 1977) Thermal overload protection for electric motors on motor-operated valves . 

AR375 1.96 Design of main steam isolation valve leakage control systems for boiling water reactor nuclear... 

Main Steam Isolation Valve Leakage Control System (BWR)... 

D Radiological Consequences of a Design Basis Loss-of-Coolant Accident Leakage From Main Steam Isolation Valve Leakage Control System (BWR)... 

Positive indication of valve leakage will be provided in the control room. Monitoring will be provided by an Acoustic Leak Monitoring System (ALMS) consisting of an accelerometer (acoustic sensor) mounted downstream of each valve. A plant annunciator alarm will be provided to alarm if the valve is not fully closed. The ALMS is part of the NSSS Integrity Monitoring System (see Section 7.7.1.6.2 for a detailed description). 

Indication of safety valve leakage is provided by the Acoustic Leak Monitoring System (ALMS). The signal from the accelerometer sensor is monitored continuously, along with the RMS value of the signal computed. These signals are compared to a pre-established baseline value and alarmed in the main control room via the Nuplex 80+ Data Processing System (DPS) and Discrete Indication and Alarm System (DIAS) displays (See Section 7.7). 

BWR MAIN STEAM ISOLATION VALVE LEAKAGE CONTROL SYSTEMS... 

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