Method and apparatus for controlling a multicompressor station
First Claim
1. A method of controlling a compressor station receiving gas from an upstream process, compressing the gas and delivering it to a process downstream thereof, said compressor station having a station control means to adjust the station performance to the demand of a process located upstream or downstream, said compressor station including also a plurality of dynamic compressors driven by a plurality of respective prime movers, each of said dynamic compressors having a variable performance, a main control means associated with each of said compressors for changing its performance and a surge control means associated with each respective compressor for maintaining said respective compressor along a surge control line having a predetermined equation and located a predetermined distance from the respective surge limit of each respective compressor;
- said method comprising;
transforming said predetermined equation of each respective surge control line into a variable criterion representing a relative distance between each respective compressor'"'"'s operating point and its surge control line, said variable criterion reaching a predetermined value when said relative distance reaches zero value;
simultaneously changing the set points for all of said respective criterions representing the relative distance between each respective compressor'"'"'s operating point and its surge control line by changing an output of said station control means to control the performance of said compressor station; and
keeping said set points equal and maintaining said criterion substantially equal at substantially all times for each of said respective compressors.
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Accused Products
Abstract
A method of control and control apparatus for load sharing between multiple compressors working in parallel and/or in series which enables all of the load-sharing compressors to carry their optimum share of the load. This load-sharing scheme follows the safest load-sharing formula and also provides for substantial energy savings. It automatically divides the load whenever a strong decoupling between process control and compressors after the compressors'"'"' operating points cross their Surge Control lines.
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Citations
9 Claims
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1. A method of controlling a compressor station receiving gas from an upstream process, compressing the gas and delivering it to a process downstream thereof, said compressor station having a station control means to adjust the station performance to the demand of a process located upstream or downstream, said compressor station including also a plurality of dynamic compressors driven by a plurality of respective prime movers, each of said dynamic compressors having a variable performance, a main control means associated with each of said compressors for changing its performance and a surge control means associated with each respective compressor for maintaining said respective compressor along a surge control line having a predetermined equation and located a predetermined distance from the respective surge limit of each respective compressor;
- said method comprising;
transforming said predetermined equation of each respective surge control line into a variable criterion representing a relative distance between each respective compressor'"'"'s operating point and its surge control line, said variable criterion reaching a predetermined value when said relative distance reaches zero value; simultaneously changing the set points for all of said respective criterions representing the relative distance between each respective compressor'"'"'s operating point and its surge control line by changing an output of said station control means to control the performance of said compressor station; and keeping said set points equal and maintaining said criterion substantially equal at substantially all times for each of said respective compressors. - View Dependent Claims (2, 3, 4, 5, 6)
- said method comprising;
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7. Apparatus for controlling a compressor station receiving a gas from upstream of a process, compressing the gas and delivering it to the process downstream thereof, said compressor station including a plurality of respective prime movers, each of said dynamic compressors having a variable performance defined by three variable parameters, a main control means associated with each of said compressors for changing the performance of each respective compressor, a surge control means associated with each respective compressor for maintaining each respective compressor along a predetermined surge control line and located a predetermined distance from the respective surge limit of each respective compressor;
- the improvement comprising;
means for maintaining one of the gas parameters constant for each respective compressor; means for computing a criterion respresenting a relative distance between each respective compressor'"'"'s operating point from the respective surge control line; set point control means for controlling one of said gas parameters by simultaneously changing the set points of each respective compressor for said criterion, representing the relative distance between each respective compressor'"'"'s operating point and its surge control line; and means for maintaining said criterion substantially equal at substantially all times for each of said compressors. - View Dependent Claims (8, 9)
- the improvement comprising;
Specification