Method and system for energy generation in a chemical plant by utilizing flare gas

A method for recovering energy, comprising:

• diverting at least a portion of a flare gas from a flare header and into a divergent path to form a diverted flare gas, wherein the flare header fluidly couples a process vessel and a flare in a chemical plant, a refinery, or a combined plant, and wherein the divergent path fluidly couples the flare header with a power generation system;
• combusting the diverted flare gas in the power generation system up to a maximum capacity of the power generation system;
• and
• storing a remaining amount of the diverted flare gas in the power generation system, combusting the remaining amount of the diverted flare gas in the flare, or both.

A system for recovering energy from a flare gas, comprising:

• a flare system comprising a flare and a flare header, wherein the flare header fluidly couples the flare to a process vessel in a chemical plant, a refinery, or a combination thereof, and the process vessel is configured to discharge a process gas into the flare header, wherein the process gas is a component of the flare gas;
• a power generation system configured to burn the flare gas, and to produce power;
• a conduit diverging from the flare header at a point between the process vessel and the flare, the conduit coupling the flare header with the power generation system to enable at least a portion of the flare gas to flow from the flare header to the power generation system;
• and
• a water weir isolating the flare from the flare header, wherein the water weir is configured to divert substantially all of the flare gas to the power generation system, and wherein water in the water weir is configured to be displaced by a high-pressure gas discharge to open a path to the flare when the high-pressure gas discharge reaches a threshold pressure.

A power generation system, comprising:

• a reciprocating engine or a burner configured to burn a low-BTU gas, wherein the low-BTU gas comprises a flare gas having an energy content greater than about 30% methane by volume;
• a chemical production plant comprising a flare system comprising the flare gas, a flare, and a flare header fluidly coupling the flare to a process vessel in the chemical production plant;
• a conduit diverging from the flare header at a point between the flare and the process vessel and fluidly coupling the flare header and the reciprocating engine or the burner, wherein the conduit is configured to divert at least a portion of the flare gas from the flare header to power the reciprocating engine or the burner;
• an energy recovery device powered by the engine or the burner;
• and
• a water weir coupled between the flare header and the flare, wherein the water weir is configured to divert substantially all of the flare gas to the reciprocating engine.