Title of Invention

METHOD FOR OPTIMIZING THE OPERATION OF A PLURALITY OF COMPRESSOR ASSEMBLIES OF A NATURAL - GAS COMPRESSION STATION

Abstract

A method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station, in which, after the start of a second or a further compressor assembly, the rotational speeds of the running compressor assemblies are run in a fixed rotational speed ratio with respect to characteristic- map data filed for each compressor assembly, thereafter this fixed rotational speed ratio is varied by means of an equal-percentage throughflow quantity adjustment via the rotational speed, until surge prevention valves of the natural- gas compression station are closed, thereafter the operating points of the compressor assemblies in their characteristic maps are lead as far as possible toward the maximum efficiency line, thereafter, in a continuous operating mode of the natural-gas compression station, set optimum rotational-speed values are determined by means of a reciprocal trimming or mutually coordinated variation of the set rotational speed values of the compressor assemblies, with the fuel consumption of the natural-gas compression station being kept under observation, and, on the basis of set optimum rotational speed values thus determined, the stored fixed rotational speed ratio is adjusted and stored.

Full Text

Description Method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station The invention relates to a method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station. Natural-gas compression stations of this kind are controlled or regulated by means of what may be referred to as station automatics, the task of which is to implement as actual values the desired values, predetermined "by" a central dispatching unit, for specific characteristic values of the natural-gas compression station. The station throughflow, which is the throughflow quantity through the natural-gas compression station, the suction pressure on the inlet side of the natural-gas compression station, the final pressure on the outlet side of the natural-gas compression station or the final temperature on the outlet side of the natural-gas compression station may function as desired values of this kind. The compressor assemblies of such natural-gas compression stations often differ from one another both in the very differently designed drive machines and in different rotors, by means of which the gas transport through the natural-gas compression station is carried out. The subject on which the invention is based is to make available a method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station, by means of which method the interaction of a plurality of compressor assemblies of the natural-gas compression station is automated in an optimum way by a regulation of the characteristic maps of the compressor assemblies, the characteristic maps of the compressor assemblies being capable of having considerable differences from one another. This object is achieved, according to the invention, in that, after the start of a second or a further compressor assembly of the natural-gas compression station, the rotational speeds of the running compressor assemblies are run in a fixed rotational speed ratio with respect to characteristic-map data filed for each compressor assembly, thereafter this fixed rotational speed ratio is varied by means of an equal-percentage throughflow quantity adjustment via the rotational speed, until surge prevention Valves of the natural-gas compression station are closed, thereafter the operating points of the compressor assemblies in their characteristic maps are lead as far as possible toward the maximum efficiency line, thereafter, in. a continuous operating mode of the natural-gas compression station, optimum rotational- speed desired values are determined by a reciprocal trimming or mutually coordinated variation of the rotational-speed desired values of the compressor assemblies, the fuel consumption of the natural-gas compression station being kept under observation, and, on the basis of optimum rotational-speed desired values thus determined, the stored fixed rotational speed ratio is adjusted and stored. By the rotational-speed desired values of the various compressor assemblies being trimmed, an optimum position of the individual operating points in the various characteristic maps of the compressor assemblies and therefore a minimum use of fuel for the compressor output demanded by the natural-gas compression station are achieved. By virtue of the minimization of fuel consumption achieved in this way, the emission of the exhaust-gas quantity and therefore the emission of NOx and CO2 are reduced. The above-outlined sequence control for the purpose of minimizing the fuel consumption of the natural-gas compression station can advantageously be implemented on the basis of the automation program installed for operating the natural-gas compression station, so that there is no need for a separate optimization program or any other program module. In the method according to the invention, optimization, taking into account the minimization of the fuel consumption of the natural-gas compression station, is carried out by means of mutually coordinated characteristic-curve displacements of the individual compressor assemblies. In an advantageous embodiment of the method according to the invention, the rotational-speed desired values for the individual compressor assemblies are transmitted by a station controller of the natural-gas compression station to individual rotational-speed controllers of the individual compressor assemblies, the controlled variable used for the station controller being that controlled variable of a plurality of controlled variables which has the lowest positive control deviation. The station throughflow or throughflow quantity, the suction pressure, the final pressure or the final temperature of the natural-gas compression station may function as controlled variables. The trimming or the mutually coordinated variation of the rotational-speed desired values of the individual compressor assemblies of the natural-gas compression station, taking into account the minimization of the fuel consumption of the entire natural-gas compression station, can advantageously be carried out by means of an optimization computer arranged between the station controller and the individual rotational-speed controllers of the individual compressor assemblies. The invention is explained in more detail below with reference to an embodiment, Fig. 1 showing compressor characteristic maps of compressor assemblies, and Fig. 2 showing an operating and observation surface of a PC monitor used for controlling a compressor station. A natural-gas compression station has a multiplicity of individual compressor assemblies which have at least partially different drive machines and different rotors, this being attributable, for example, to the fact that compressor assemblies are designed for covering basic-load operation and compressor assemblies are designed for covering peak-load operation. In order to optimize the operation of a plurality of compressor assemblies of a natural-gas compression station, after the successful start of a further or additional compressor assembly of the natural-gas compression station, a station controller of the natural-gas compression station will run the rotational speeds of the now operative compressor assemblies of the natural-gas compression station in a fixed rotational speed ratio to the characteristic-map data filed for each compressor assembly. This fixed rotational-speed ratio is subsequently varied by means of an equal-percentage throughflow quantity adjustment via the rotational speed of the individual compressor assemblies, until surge prevention valves present in the natural-gas compression station are closed. Due to the closing of the surge prevention valves, a first fuel reduction takes place during the operation of the natural-gas compression station. What is achieved at the same time by the closing of the surge prevention valves is that the transport gas to be compressed or transported by means of the natural-gas compression station is heated to a lesser extent, with the result that, in turn, the energy balance at the natural-gas compression station has a more favorable configuration. When all the surge prevention valves of a natural-gas compression station are closed, the operating points of the individual compressor assemblies in their characteristic maps are lead toward their maximum efficiency line, in so far as this is possible. During the subsequent continuous operating mode of the natural-gas compression station, optimum values for the rotational-speed desired values of the individual compressor assemblies are then searched for by means of a reciprocal trimming or mutually coordinated variation of the rotational-speed desired values of the individual compressor assemblies and the observation of the overall fuel consumption of the natural-gas compression station. After these optimum rotational-speed desired values are determined for the individual compressor assemblies, the abovementioned fixed rotational speed ratio with respect to the filed characteristic-map data is adjusted according to the optimum rotational-speed desired values determined and is then stored. The controlled variable having the lowest positive control deviation functions as the controlled variable for the station controller of the natural-gas compression station. The rotational-speed desired value for the individual compressor assemblies is made available on the output side of the station controller. The transfer of these rotational-speed desired values made available on the output side of the station controller to the individual compressor assemblies is carried out by rotational-speed controllers which are assigned to the individual control units of the individual compressor assemblies. In order to take into account the different design of the individual compressor assemblies, the rotational- speed desired values, before being transmitted to the rotational-speed controllers of the individual compressor assemblies, are trimmed by an optimization computer connected between the station controller and these individual rotational-speed controllers. WE CLAlM: 1. A method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station, in which, after the start of a second or a further compressor assembly, the rotational speeds of the running compressor assemblies are run in a fixed rotational speed ratio with respect to characteristic-map data filed for each compressor assembly, thereafter this fixed rotational speed ratio is varied by means of an equal-percentage throughflow quantity adjustment via the rotational speed, until surge prevention valves of the natural-gas compression station are closed, thereafter the operating points of the compressor assemblies in their characteristic maps are lead as far as possible toward the maximum efficiency line, thereafter, in a continuous operating mode of the natural-gas compression station, set optimum rotational-speed values are determined by means of a reciprocal trimming or mutually coordinated variation of the set rotational speed values of the compressor assemblies, with the fuel consumption of the natural-gas compression station being kept under observation, and, on the basis of set optimum rotational speed values thus determined, the stored fixed rotational speed ratio is adjusted and stored. 2. The method as claimed in claim 1, the sequence control of which is implemented on the basis of the automation program installed for operating the natural-gas compression station. 3. The method as claimed in claim 1 or 2, wherein the rotational-speed desired values for the compressor assemblies are transmitted by a station controller to rotational-speed controllers of the compressor assemblies, the controlled variable used for the station controller being that controlled variable of a plurality of controlled variables which has the lowest positive control deviation. 4. The method as claimed in one of claims 1 to 4, wherein the station throughflow or the throughflow quantity, the suction pressure, the final pressure or the final temperature of a natural-gas compression station function as controlled variables. 5. The method as claimed in claim 3 or 4, wherein the trimming or the mutually coordinated variation of the rotational-speed desired values of the compressor assemblies of the natural-gas compression station is carried out by means of an optimization computer arranged between the station controller and the rotational-speed controllers of the compressor assemblies. A method for optimizing the operation of a plurality of compressor assemblies of a natural-gas compression station, in which, after the start of a second or a further compressor assembly, the rotational speeds of the running compressor assemblies are run in a fixed rotational speed ratio with respect to characteristic- map data filed for each compressor assembly, thereafter this fixed rotational speed ratio is varied by means of an equal-percentage throughflow quantity adjustment via the rotational speed, until surge prevention valves of the natural- gas compression station are closed, thereafter the operating points of the compressor assemblies in their characteristic maps are lead as far as possible toward the maximum efficiency line, thereafter, in a continuous operating mode of the natural-gas compression station, set optimum rotational-speed values are determined by means of a reciprocal trimming or mutually coordinated variation of the set rotational speed values of the compressor assemblies, with the fuel consumption of the natural-gas compression station being kept under observation, and, on the basis of set optimum rotational speed values thus determined, the stored fixed rotational speed ratio is adjusted and stored.

Documents:

502-KOLNP-2004-FORM-27.pdf

502-kolnp-2004-granted-abstract.pdf

502-kolnp-2004-granted-claims.pdf

502-kolnp-2004-granted-correspondence.pdf

502-kolnp-2004-granted-description (complete).pdf

502-kolnp-2004-granted-drawings.pdf

502-kolnp-2004-granted-examination report.pdf

502-kolnp-2004-granted-form 1.pdf

502-kolnp-2004-granted-form 18.pdf

502-kolnp-2004-granted-form 2.pdf

502-kolnp-2004-granted-form 3.pdf

502-kolnp-2004-granted-form 5.pdf

502-kolnp-2004-granted-gpa.pdf

502-kolnp-2004-granted-reply to examination report.pdf

502-kolnp-2004-granted-specification.pdf