Compressor Design and Operation

Acid gas behaves differently from sweet gas inside the compressor. Simulation of the actual compression horsepower and temperature rise inside the compressor must be given careful consideration. Of course, the cooling is also an important consideration. Not properly accounting for water condensation and non-aqueous phase changes (especially in final stage) can result in undersized coolers. 

Compressor speed is automatically controlled to ensure that the system can respond rapidly and accurately to changes in acid 

The low suction pressure is not a major concern in the design of the compressor other than the need to be very conservative in sizing of piping, valves, and vessels. 

Discharge temperatures should be limited to about 150°C (300°F) and should never exceed 180°C (350°F). By maintaining relatively low discharge temperatures damage to the compressor, notably the packing, is reduced. In addition, high temperature can cause degradation of the compressor fluids, such as the lube oil. 

Fuel gas make-up should not be used to boost suction pressure. The effect on wellhead injection is too volatile and unpredictable. As will be demonstrated, the light hydrocarbons can significantly affect the required injection pressures. 

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