Minimal sour gas emission for an integrated gasification combined cycle complex

Abstract

Disclosed is a process to start-up, operate, and shut down a gasifier and an integrated gasification combined cycle complex with minimal sour gas emissions while additionally reducing the release of contaminants such as carbon monoxide, hydrogen sulfide, and nitrogen oxides. The process is accomplished by starting up with a sulfur free feedstock and by scrubbing any ventable sour gases free of sulfur contaminants prior to release of any such gases to the atmosphere.

Description

[0001]This application claims benefit of provisional application Ser. No. 61 / 084,774 filed Jul. 30, 2008, which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]The present invention relates to systems and methods of starting up, operating and shutting down a gasification reactor and an integrated gasification combined cycle (“IGCC”) complex.[0003]Gasification was first used to produce “town gas” for light and heat. Additionally, coal and other hydrocarbons have been gasified in the past to produce various chemicals and synthetic fuels. More recently gasification technology has been employed to generate electricity in an IGCC complex wherein coal or another hydrocarbon is gasified by partial oxidation using oxygen or air to syngas. Typically, this syngas is then cleaned of particulates, sulfur compounds and nitrogen compounds such as NOx compounds and then subsequently passed to gas turbine where it is fired. Additionally the hot exhaust gas from ...

AI Technical Summary

Benefits of technology

"The present invention is about a process for collecting and treating potential contaminants or pollutants in blow down conduits associated with process units that comprise an IGCC complex. The process involves removing sulfur from the contaminant streams and separating them into oxidizing and reducing streams. The oxidizing stream is then flared using a flare system, while the reducing stream is either used for energy recovery or sent to a separate treatment unit. The invention aims to prevent the emission of contaminants into the atmosphere and recover useful gas products from the process."

Problems solved by technology

Second, the total sulfur content is limited to 30 ppmv or less to further minimize corrosion issues and to mitigate any health concerns to workers or the public in the event of a mechanical failure or release, Third, nitrogen in the product is limited to less than about 2 vol % since excessive amounts of nitrogen may significantly inhibit EOR and permanent sequestration of CO2.

As is well known to those skilled in the art, this results in higher than normal emissions of contaminants such as sulfur.

Accordingly, the start-up of a partial oxidation gas generator presents special challenges, including dealing with the contaminant emissions.

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