Archive for January, 2010

Gas compressor problems

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Referring back to Figure 10—1, remember that we have compared the actual gas compressor speed to the speed indicated by the curve that passes through point “A”. We calculated point “A” from the natural gas flow, and the observed suction and discharge pressure. We said that if the measured gas compressor speed exceeded the speed …

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Gas turbine air compressor problems

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One way of looking at a gas turbine centrifugal compressor is that the combustion air compressor must pump sufficient air to support combustion across the turbine blades as needed to spin the gas compressor at its required speed. Any factors which reduce the flow delivered by the combustion air compressor will reduce horsepower available to …

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Gas turbine exhaust temperature unit troubleshooting

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Gas turbines are limited, as are all rotating assemblies, by either speed or power. For an electric motor, the power limit is manifested by maximum amperage, (more precisely, the maximum permissible winding temperature). The situation with gas turbines is similar. The ultimate amount of power (i.e. work, horsepower), that can be developed by the turbine …

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Troubleshooting gas turbine drivers

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A centrifugal compressor driven by a gas turbine at a pipeline booster station is moving 80 MMSCFD of natural gas. It used to move 95 MMSCFD. What’s wrong? As the troubleshooter, consider whether the problem is with the driver or the compressor. Actually, there are three primary components involved: • The combustion air compressor. • …

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Gas Turbine Driven Centrifugal Compressors

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While the majority of natural gas field and transmission compressors are reciprocating machines, a sizable minority are centrifugal compressors driven by gas turbines. Only on rare occasions can electric, steam or deisel oil drives compete with natural gas as compressor fuel in pipeline service. A gas turbine works on the same principle as a jet …

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Compression work vs. temperature rise

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A handy rule of thumb to retain for compression troubleshooting jobs is that the theoretical temperature increase of gas due to compression is linearly proportional to compression horsepower. An extremely useful application of this rule of thumb is the following approximation: It is not too much to say that this relationship is the most important …

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