Method for controlling a multicompressor station

• US 4,640,665 A
• Filed: 11/13/1984
• Issued: 02/03/1987
• Est. Priority Date: 09/15/1982
• Status: Expired due to Term

• Current Assignee: Ropintassco Holdings, L.P. (Roper Technologies, Inc.)
• Original Assignee: Compressor Controls Corporation (Roper Technologies, Inc.)
• Inventors: Staroselsky, Naum, Mirsky, Saul
• Primary Examiner(s): Casaregola, Louis J.
• Application Number:
  US06/657,200
• Time in Patent Office: 812 Days
• Field of Search: 415/1, 415/11, 415/26, 415/27, 415/28, 417/2, 417/3, 417/4, 417/5, 417/286
• US Class Current: 415/1
• CPC Class Codes: F02C 6/00 Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
• CPC Class Codes: F04D 27/0261 by varying driving speed
• CPC Class Codes: F04D 27/0269 by changing flow path between different stages or between a plurality of compressors; load distribution between compressors
• CPC Class Codes: F04D 27/0284 Conjoint control of two or more different functions
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A method of control 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.

Claims

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 one dynamic compressor driven by a prime mover, said dynamic compressor having a variable performance, a main control means associated with said compressor for changing its performance, and a surge control means associated with said compressor for maintaining said compressor along a surge control line having a predetermined equation and located a predetermined distance from its surge limit;

said method comprising;

transforming said predetermined equation of said surge control line into a variable criterion representing a relative distance between said compressor'"'"'s operating point and its surge control line, said variable criterion reaching some predetermined value when said relative distance reaches zero value; and

changing set points for said criterion representing the relative distance between said 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 limiting said set points and providing for a decoupling between said compressor and said station control means to avoid a dangerous approaching of said surge limit line after the compressor'"'"'s operating point crosses its surge control line and reaches some predetermined deviation from said control line.

2. A method of 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 at least one dynamic compressor driven by at least one respective prime mover, each of said dynamic compressors having a variable performance defined by three variab parameters, a main control means associated with each of said at least one compressor 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;

said method comprising;

maintaining one of the gas parameters constant for each respective compressor;

computing a criterion representing a relative distance between each respective compressor'"'"'s operating point from the respective surge control line;

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

maintaining said criterion substantially equal at substantially all times for each of said compressors.