Systems and processes of eliminating start-up flaring in a gas plant

A process for eliminating start-up flaring in a gas plant utilizing flare stack diversion logic, wherein:

• a natural gas source is configured to supply a natural gas feed to a running train and a start-up train, the start-up train and the running train both comprising one or more natural gas treatment units operating with identical parameters;
• a start-up train flow-path comprises the start-up train fluidly connected to and downstream from the natural gas source, a start-up train flow valve fluidly connected and downstream from the start-up train, a start-up train flow valve actuator coupled to the start-up train flow valve, and a natural gas feed parameter sensor downstream of the start-up train and upstream of the start-up train flow valve;
• a running train flow-path comprises a running train shutoff valve fluidly connected to and downstream from the natural gas source, a running train shutoff valve actuator coupled to the running train shutoff valve, and the running train fluidly connected to and downstream from the running train shutoff valve;
• a bypass flow-path comprising a block valve and a check valve, the block valve fluidly connecting the outlet of the start-up train to an inlet of the running train, the bypass flow-path interposed between the start-up train outlet and the start-up train flow valve, as well as the running train shutoff valve and the running train inlet, and the check valve interposed between the block valve and the inlet of the running train;
• a flare stack diversion controller is communicatively coupled to the start-up train flow valve actuator, the running train shutoff valve actuator, and the natural gas feed parameter sensor, wherein the flare stack diversion controller is configured to actuate the running train shutoff valve actuator to selectively open or close the running train shutoff valve and is programmed to execute a process utilizing flare stack diversion logic;
• and
• the process utilizing flare stack diversion logic comprises:
• detecting one or more natural gas feed parameters from the natural gas feed parameter sensor during start-up,
• receiving the one or more natural gas feed parameters from the natural gas feed parameter sensor,
• determining whether the one or more natural gas feed parameters fall outside pre-defined bounds of the natural gas feed parameters,
• generating an alert or message to open the block valve upon determining the one or more natural gas feed parameters fall outside the pre-defined bounds,
• determining whether the block valve has been opened,
• closing the start-up train flow valve upon determining the block valve has been opened,
• closing the running train shutoff valve, and
• diverting all flow from the running train flow-path to the start-up train flow-path through the block valve and to the running train to eliminate start-up flaring.

A system for eliminating start-up flaring in a gas plant utilizing flare stack diversion logic, the system comprising:

• a first natural gas source configured to supply a natural gas feed to a start-up train;
• a second natural gas source configured to supply the natural gas feed to a running train, the start-up train and the running train each comprising a natural gas treatment unit, the start-up train natural gas treatment unit and the running-train natural gas treatment unit operating with identical parameters;
• a start-up train flow path comprising the start-up train fluidly connected to and downstream from the first natural gas source, a start-up train flow valve fluidly connected and downstream from the start-up train, a start-up train flow valve actuator coupled to the start-up train flow valve, and a natural gas parameter sensor downstream of the start-up train and upstream of the start-up train flow valve;
• a running train flow-path having a relatively lesser fluid pressure than the start-up train flow-path and comprising the running train fluidly connected to and downstream from the second natural gas source;
• a bypass flow-path comprising a bypass flow valve and a check valve, the control valve fluidly connecting the outlet of the start-up train to an inlet of the running train, the bypass flow- path interposed between the start-up train outlet and the start-up train flow valve, as well as the second natural gas source and the running train inlet, and the check valve interposed between the control valve and the inlet of the running train;
• the flare stack diversion controller is communicatively coupled to the start-up train flow valve actuator and the natural gas feed parameter sensor, wherein the flare stack diversion controller is configured to actuate the start-up train flow valve actuator and the bypass flow valve actuator to selectively open or close the start-up train flow valve and the bypass flow valve, respectively, the flare stack diversion controller also programmed to execute flare stack diversion logic, comprising:
• detecting one or more natural gas feed parameters from the natural gas feed parameter sensor during start-up,
• receiving one or more natural gas feed parameters from the natural gas feed parameter sensor,
• determining whether the one or more natural gas feed parameters fall outside pre-defined bounds of the natural gas feed parameters,
• closing the start-up train flow valve upon determining the one or more natural gas feed parameters fall outside the pre-defined bounds, and
• opening the bypass flow valve within the bypass flow-path to eliminate start-up flaring of the natural gas feed.