Compressors choke

The use of dynamic pressure transducers gives early warning of problems in the compressor. The very high pressure in most of the advanced gas turbines cause these compressors to have a very narrow operating range between surge and choke. Thus, these units are very susceptible to dirt and... 

DIAGNOSTICS OUTPUTS Compressor Efficiency Lower than Design Compressor Approaching Surge Conditions Compressor Approaching Choke Conditions Dirty Compressor... 

The increase in compressor pressure ratio decreases the operating range of the compressor. The operating range of the compressor stretches from the surge line at the low flow end of the compressor speed line to the choke point... 

A stonewall or choked flow condition occurs when sonic velocity is reached at the exit of a compressor wheel. When this point is reached, flow through the compressor cannot be increased even with further... 

Low Pass Filter Two chambers are connected by a choke tube or pipe. At least one of the chambers should be connected to the compressor cylinder. Figures 13-lB and 13-lC. Melton offers a standardized, simple design that is useful for some types of package compressor arrangement. 

Install a two-bottle filter system for the 10 in. X 14 in. double-acting compressor, each bottle to be 16 in. c ) X /g in. W.T X 3 ft-6 in. long with weld caps. Install a 2 in. Sch. 40 choke-tube between bottles 20 ft total length. Install 90° elbows or baffles at entrance and exit of each bottle. 

A natural gas (methane) pipeline is to be designed to transport the gas at a rate of 50,000 scfm. The pipe is to be 6 in. ID, and the maximum pressure that the compressors can develop is 10,000 psig. The compressor stations are to be located in the pipeline at the point at which the pressure drops to 100 psi above that at which choked flow would occur (this is the suction pressure for the compressors). If the design temperature for the pipeline is 60°F, the compressors are 60% efficient, and the compressor stations each operate with three stages and interstage cooling to 60°F, determine... 

Natural gas (CH4) is transported through a 6 in. ID pipeline at a rate of 10,000 scfm. The compressor stations are 150 mi apart, and the compressor suction pressure is to be maintained at lOpsig above that at which choked flow would occur in the pipeline. The compressors are each two stage, operate adiabatically with interstage cooling to 70°F, and have an efficiency of 60%. If the pipeline temperature is 70°F, calculate ... 

The scope of coverage includes internal flows of Newtonian and non-Newtonian incompressible fluids, adiabatic and isothermal compressible flows (up to sonic or choking conditions), two-phase (gas-liquid, solid-liquid, and gas-solid) flows, external flows (e.g., drag), and flow in porous media. Applications include dimensional analysis and scale-up, piping systems with fittings for Newtonian and non-Newtonian fluids (for unknown driving force, unknown flow rate, unknown diameter, or most economical diameter), compressible pipe flows up to choked flow, flow measurement and control, pumps, compressors, fluid-particle separation methods (e.g.,... 

Types of compressors Industrial Aerospace Research Efficiency, % Operating range surge — choke, %... 

Control can be exercised by the operator in the control roam on the well chokes and manifold divert valves (although this is normally handled by the HOC), start/atop of the oil shipping pumps, utility equipment, switching valves, gas plant feed valves, gas compressor start/stop and emergency shutdown of any production train or the entire GC. Since the closed loop process control is performed by local pneumatic instruments, all set point changes and controller troubleshooting must be accomplished locally. 

Volumetric flow rates of different gases are often compared to equivalent volumes of air at standard atmospheric temperature and pressure. The ideal gas law works well when used to size fans or compressors. Unfortunately, the gas law relationship, PV/T = constant, is frequently applied to choked gas streams flowing at sonic velocity. A typical misapplication could then be the conversion to standard cubic feet per minute in sizing SRVs. Whether the flow is sonic or subsonic depends mainly on the backpressure on the SRV outlet. In the API calculations, this is taken into account by the backpressure correction factor. 

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