Generating power from natural gas with carbon dioxide capture

摘要

Methods include producing a hydrogen rich fuel gas for a gas turbine ballasted with nitrogen and steam and superheated to a temperature above its dew point. The fuel gas may have a minimal or reduced content of CO2 or fuel components CO and CH4 which contain carbon so that when combusted in a suitable gas turbine there may be minimal or reduced emissions of CO2 to the atmosphere. These methods may result in a capture of the bulk of the carbon present in the total natural gas feed as CO2 compressed to pipeline delivery pressure for sequestration.

主权项

1. A method for producing fuel gas mixture comprising;
exothermically reacting a first portion of a hydrocarbon feed stream with steam, an oxidant gas comprising molecular oxygen to produce an exothermically generated syn-gas product, or a combination of the steam and the oxidant gas; endothermically reforming a second portion of the hydrocarbon feed stream with steam over a catalyst in a heat exchange reformer to produce an endothermically-reformed syn-gas product, wherein at least a portion of heat used in generation of the endothermically-reformed syn-gas product is obtained by recovering heat from the exothermically-generated syn-gas product and the endothermically reformed syn-gas product; cooling a combination of the endothermically-reformed syn-gas product and the exothermically-generated syn-gas product to generate a cooled syn-gas stream; reducing a pressure of the cooled syn-gas stream in a power producing expansion turbine to the to generate a lower-pressure stream having a pressure for a power producing gas turbine; catalytically reacting the lower-pressure syngas in one or more catalytic carbon monoxide shift reactors to generate a combined stream including additional hydrogen (H2) and carbon dioxide (CO2); cooling the combined stream to near ambient temperature in a multipassage multi stream plate-fin heat exchanger which heats water for steam production for the syn-gas generation system and preheats fuel gas product and evaporates water for mixing with the fuel gas product; removing CO2 from the combined stream to generate a CO2-depleted syn-gas having a CO2 concentration below a specified threshold; generating oxygen and nitrogen in an air separation unit which is supplied with air produced from air compressors driven by a first gas turbine; mixing at least part of the nitrogen from the air separation unit with the CO2 depleted syn-gas plus evaporated water to provide a fuel gas for a second power producing gas turbine; and utilizing at least part of the heat in the first gas turbine exhaust, preheating fuel plus oxygen plus steam feeds to the syn-gas generation system.