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US 12,486,980 B2Granted
Vent gas recovery with flare control during a flare event
AssigneeChevron Phillips Chemical Company LP
InventorDaniel W. Peneguy
Life of this patent
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Abstract
Flare control with vent gas recovery is disclosed. Vent gas is recovered for end use (e.g., process gas, fuel gas, etc.) while a flare is in a standby state. Upon detection of a flare event that causes vent gas to flow to the flare, the flare is changed from the standby state to an active state. The flare is controlled for efficient combustion of vent gas that flows to the flare during the flare event. Upon detection of a subsidence of the flare event, the flare is changed from the active state to the standby state. The flare can remain in standby until another flare event is detected. The flare event is detected when one or more of the disclosed flare activation conditions are detected, and subsidence of the flare event is detected when the flare deactivation conditions are detected.
Claims19
A flare control and vent gas recovery apparatus comprising:
- a raw vent gas stream configured to split into a first stream and a second stream;
- a vent gas recovery system having an inlet fluidly coupled to the first stream;
- a pressure seal apparatus having a seal inlet fluidly coupled to the second stream;
- a vent gas stream having a vent gas flow meter located therein, wherein the vent gas stream is fluidly coupled to the seal inlet or to a seal outlet of the pressure seal apparatus, wherein the pressure seal apparatus has a differential pressure sensor fluidly coupled to the seal inlet and to the seal outlet, wherein the pressure seal apparatus has a liquid level sensor configured to indicate a liquid level in the pressure seal apparatus;
- a supplemental fuel gas stream fluidly coupled to the vent gas stream downstream of a first location in the vent gas stream where the seal outlet is coupled to the vent gas stream, wherein the supplemental fuel gas stream has a supplemental fuel gas flow meter located therein;
- a flare fluidly coupled to the vent gas stream downstream of a second location in the vent gas stream where the supplemental fuel gas stream is fluidly coupled to the vent gas stream;
- and
- a flare control system coupled to the differential pressure sensor, the liquid level sensor, the vent gas flow meter, and the supplemental fuel gas flow meter, wherein the flare control system is configured to i) detect a flare activation condition or a plurality of flare deactivation conditions and ii) adjust the flare between a standby state and an active state.
5 more elements
A method comprising:
- flowing, while a flare is in an active state, a vent gas to a vent gas recovery system and to the flare;
- controlling, in real-time based at least in part on a concentration of at least one hydrocarbon in a vent gas stream, i) a flow of supplemental fuel gas and a flow of steam to the flare or ii) a flow of supplemental fuel gas and a flow of air to the flare;
- detecting, while the flare is in the active state, a plurality of flare deactivation conditions;
- and
- adjusting the flare from the active state to a standby state based on detecting,
- wherein the plurality of flare deactivation conditions comprise:
- i) a first signal received from a differential pressure sensor of a pressure seal apparatus, wherein the first signal indicates that a differential pressure between a seal inlet and a seal outlet of the pressure seal apparatus is less than a static head pressure of a liquid in the pressure seal apparatus;
- ii) a second signal received from a liquid level sensor of the pressure seal apparatus, wherein the second signal indicates that a liquid level in the pressure seal apparatus is at or above a setpoint liquid level;
- and iii) a third signal received from a vent gas flow meter, wherein the third signal indicates that a flow rate of the vent gas in the vent gas stream is zero.
6 more elements
A method comprising:
- flowing, while a flare is in a standby state, a vent gas to a vent gas recovery system;
- detecting one or more flare activation conditions;
- adjusting the flare from the standby state to an active state based on detecting the one or more flare activation conditions;
- controlling, while the flare is in the active state and in real-time based at least in part on a concentration of at least one hydrocarbon in a vent gas stream that is fluidly connected to the flare, i) a flow of supplemental fuel gas and a flow of steam to the flare or ii) a flow of supplemental fuel gas and a flow of air to the flare;
- flowing, while the flare is in the active state, the vent gas to the vent gas recovery system and to the flare;
- detecting, while the flare is in the active state, a plurality of flare deactivation conditions;
- and
- adjusting the flare from the active state to the standby state based on detecting the plurality of flare deactivation conditions;
- wherein the plurality of flare deactivation conditions comprise:
- i) a first signal received from a differential pressure sensor of a pressure seal apparatus, wherein the first signal indicates that a differential pressure between a seal inlet and a seal outlet of the pressure seal apparatus is less than a static head pressure of a liquid in the pressure seal apparatus;
- ii) a second signal received from a liquid level sensor of the pressure seal apparatus, wherein the second signal indicates that a liquid level in the pressure seal apparatus is at or above a setpoint liquid level;
- and iii) a third signal received from a vent gas flow meter, wherein the third signal indicates that a flow rate of the vent gas in the vent gas stream is zero.
9 more elements
Dependencies are inferred from the claim text.