Compressor discharge temperature monitor and alarm

Abstract

A compressor protection method and system capable of continuously establishing compressor discharge temperature set points based on actual in-service conditions and detecting damaged compressor valves for a given cylinder at each stage of compression. The method and system utilize sensors configured to monitor process property parameters (e.g. temperature and pressure) at the inlet section and outlet section of a compressor stage. The sensors generate monitored signals corresponding to the process property parameters. The method and system utilize a controller configured to receive and process these monitored signals. The controller executes a control logic that uses the monitored signals to either estimate or calculate compressor valve pressure losses for determining internal cylinder pressures, which are used to calculate compressor discharge temperature set points. The control logic compares the monitored temperature to the temperature set points and may generate a warning or normal operation signals based on results of the comparison.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 482,952 filed on May 5, 2011, which is hereby incorporated by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicable.THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT[0003]Not applicable.INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC[0004]Not applicable.BACKGROUND OF THE INVENTION[0005]1. Field of the Invention[0006]The present disclosure relates to subject matter for pumping fluids, in particular reciprocating compressors having a separate sensor that is responsive to the occurrence of a condition or a change in condition of either the compressor or the gas being compressed.[0007]2. Description of Related Art[0008]Reciprocating compressors are often utilized to increase the pressure of a gas by displacing a positive volume of gas by alternatively filling and discharging a cylinder b...

AI Technical Summary

Benefits of technology

The present invention provides a compressor protection method and system that can continuously establish variable compressor discharge temperature set points based on actual in-service conditions and detect damaged compressor valves for a given cylinder at each stage of compression. The method and system use sensors to monitor process property parameters at the inlet and outlet sections of a compressor stage, and a controller to execute a control logic that uses the monitored signals to calculate compressor valve pressure losses and determine internal cylinder pressures, which are used to calculate compressor discharge temperature set points. The control logic compares the monitored temperature to the temperature set points and may generate a warning or normal operation signals based on the results of the comparison. The invention can provide more practical and cost effective protection for compressors and improve operational efficiency.

Problems solved by technology

Failure of these valves can have significant consequences, including the loss of rod force reversals during each stroke.

The loss of adequate lubrication at these components will often result in extensive compressor damage and / or failure (e.g. premature bearing wear or failure, and so forth) leading to forced outages, loss of production, safety risks to workers, inefficient operation, unnecessary maintenance work and high repair costs.

However, systems with a fixed operator determined constant temperature set point are often inadequate to address the reality of actual in-service conditions.

In the case of a fixed set point that is too low, this may result in a false alarm leading to costly and unnecessary shutdowns and lost production time.

Alternatively, in the case of a set point that is too high, this may result in compressor valve failure or damage going unnoticed.

Thus, a protection system with a fixed operator determined temperature set point discharge temperature that does not continuously update based on changing service conditions may be inadequate to protect a compressor.

However, this type of system also has disadvantages.

Significantly, this type of continuous analyzer system can be extremely costly because it typically requires special pressure sensors installed to measure internal cylinder pressures and adapted for severe pulsation and a very fast response time.

In addition, this system has high operating costs because of the severe pulsation within a compressor cylinder, which causes the load sensing diaphragm of the special pressure sensor to experience metal fatigue causing intermittent failures, which require high cost replacement sensors.

Further, theoretical discharge temperatures calculated with this system are often inaccurate, particularly for high-speed compressors, because the system uses terminal pressure to calculate theoretical discharge temperature.

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