System and method for use of a train feed gas loading automation optimizer

Abstract

A system has a gas processing plant having a compressor, at least one natural gas liquids (NGL) train fluidly coupled to the compressor to receive mixed natural gas liquids from the gas processing plant, a valve fluidly coupling the gas processing plant to the at least one natural gas liquids train, and a control system coupled to the gas processing plant, the at least one natural gas liquids train, and the valve. The control system determines when to actuate the valve using a virtual sensing system based on a compressor shutdown condition, a compressor trip condition, a compressor recycle condition, an exclusion switch, a flow rate of the compressor, a running flow capacity of the first compressor, a required bypass flow of the compressor, and bypass flow distribution of the at least one natural gas liquids train.

What is claimed: 
     
         1 . A system, comprising:
 a gas processing plant, wherein the gas processing plant comprises a compressor;   at least one natural gas liquids train fluidly coupled to the compressor to receive mixed natural gas liquids from the gas processing plant;   a valve fluidly coupling the gas processing plant to the at least one natural gas liquids train; and   a control system coupled to the gas processing plant, the at least one natural gas liquids train, and the valve,   wherein the control system determines when to actuate the valve using a virtual sensing system based on a compressor shutdown condition, a compressor trip condition, a compressor recycle condition, an exclusion switch, a flow rate of the compressor, a running flow capacity of the first compressor, a required bypass flow of the compressor, and bypass flow distribution of the at least one natural gas liquids train.   
     
     
         2 . The system of  claim 1 , further comprising a plurality of sensors coupled to the compressor, the valve and the at least one natural gas liquids train. 
     
     
         3 . The system of  claim 2 , wherein the plurality of sensors are in communication with the control system. 
     
     
         4 . The system of  claim 1 , further comprising a second gas processing plant, wherein the second gas processing plant comprises a second compressor in fluid communication with at least one natural gas liquids train. 
     
     
         5 . The system of  claim 4 , wherein the control system determines when to actuate a second valve fluidly coupling the second gas processing plant to the at least one natural gas liquids train using the virtual sensing system. 
     
     
         6 . The system of  claim 1 , wherein the control system is a distributed control system (DCS). 
     
     
         7 . The system of  claim 1 , wherein the at least one natural gas liquids train comprises a deethanizer, a depropanizer, a debutanizer, and a deisobutanizer. 
     
     
         8 . A method, comprising:
 receiving, with a control system, a signal from a compressor of a gas processing plant;   determining, with the control system, a status of the compressor based on the signal;   determining, with the control system, when to actuate a valve coupled on the compressor based a compressor shutdown condition, a compressor trip condition, a compressor recycle condition, an exclusion switch, a flow rate of the compressor, a running flow capacity of the first compressor, a required bypass flow of the compressor, and bypass flow distribution of a natural gas liquids train; and   flowing a mixture of natural gas liquids from the compressor to the natural gas liquids train.   
     
     
         9 . The method of  claim 8 , further comprising:
 adjusting, with a control system, a flow rate through the compressor.   
     
     
         10 . The method of  claim 8 , further comprising:
 rejecting, with a control system, excess flow entering compressor to not exceed the running flow capacity.   
     
     
         11 . The method of  claim 8 , further comprising:
 determining, with a control system, the required bypass flow by subtracting the running flow capacity from the flow rate.   
     
     
         12 . The method of  claim 11 , further comprising:
 reducing, with a control system, a volume of the mixture of natural gas liquids entering the natural gas liquids train.   
     
     
         13 . The method of  claim 8 , wherein the signal is a flow rate measurement from a sensor coupled to the compressor. 
     
     
         14 . A non-transitory computer readable medium storing instructions on a memory coupled to a processor, the instructions comprising functionality for:
 triggering the processor to initiate the instructions when a turbine flame out trip signal from a compressor of a gas processing plant is received by the processor;   determining if the compressor is in a recycle mode or a shutdown mode;   calculating an amount of flow reduction from the gas processing plant to a natural gas liquids train; and   closing or partially closing, based on the calculated flow reduction, an opening of a valve to natural gas liquids train to restrict a gas feed stream from the gas processing plant to the natural gas liquids train.   
     
     
         15 . The non-transitory computer readable medium of  claim 14 , wherein the instructions further comprise functionality for:
 developing switches corresponding to a condition of the compressor,   wherein the developed switches are a shutdown switch, a recycle switch, a trip switch, and an exclusion switch.   
     
     
         16 . The non-transitory computer readable medium of  claim 15 , the instructions further comprise functionality for:
 calculating a current flow on the compressor utilizing a tag from a pressure valve in the compressor.   
     
     
         17 . The non-transitory computer readable medium of  claim 14 , wherein the instructions further comprise functionality for:
 calculating a required bypass flow from the gas processing plant to the natural gas liquids train.