Air bottoming cycle for coal gasification plant
AssigneeGeneral Electric Company
InventorsEdgar D. Alderson, William M. Farrell
Life of this patent
Estimating the term…
Abstract
In a coal gasification plant there is a requirement for supplying oxygen to the coal gasifier in order to produce coal gas fuel. An oxygen plant will produce oxygen and nitrogen from an input supply of compressed air. In the presence of a fired gas turbine which is supplied with coal gas fuel, the waste heat from the fired gas turbine may be used to heat compressed air for driving an air cycle turbine. The air cycle turbine in turn drives an air cycle compressor for producing air to the oxygen plant. The nitrogen gas by-product from the oxygen plant is injected into the air cycle for disposal through the air turbine.
Claims11
An air bottoming cycle for a coal gasification plant wherein the coal gasification plant includes an oxygen plant for converting pressurized air into oxygen and nitrogen, the oxygen being used in the coal gasification plant:
- the air bottoming cycle comprising:
- at least one air bottoming cycle first compressor;
- an air turbine connected to drive the first compressor;
- a heat exchanger connected between the first compressor and the air turbine:
- the heat exchanger for counterflowing the compressor discharge air against a heat source whereby a hot motive fluid is produced for driving the air turbine;
- an air bleed line for transferring a portion of the first compressor discharge air to the oxygen plant;
- and,
- a return line for injecting nitrogen from the oxygen plant into the first compressor discharge air.
An improved power plant of the type including a coal gasification plant for producing fuel gas for a fired gas turbine plant and an oxygen plant for producing oxygen for the coal gasification plant;
- the power plant further including a nitrogen by-product from the oxygen plant and a hot exhaust waste gas stream from the fired gas turbine plant wherein the improvement comprises:
- an unfired gas turbine plant comprising an air turbine drivingly connected to a first compressor;
- a heat exchanger having a first line connected between the first compressor and the air turbine and a second line connected between the gas turbine plant hot exhaust and an exhaust stack, said first and second lines being in heat exchange relationship whereby compressor discharge air is heated by the hot exhaust waste gas stream;
- an air bleed line connected between the first compressor discharge and the oxygen plant whereby a portion of the compressor discharge air is provided to the oxygen plant;
- and,
- a return line for injecting nitrogen into the compressor discharge at a point between the compressor discharge and the heat exchanger.
An apparatus for providing air to an oxygen plant for producing oxygen and by-product nitrogen comprising:
- a first compressor;
- an air turbine drivingly connected to the first compressor;
- a waste heat recovery heat exchanger having a first line connected to a source of heated gas and a second line, in heat exchange relation to the first line and connected at the discharge end of the first compressor and connected to the inlet end of the air turbine for providing heated air to the air turbine;
- an air bleed line connected at the discharge end of the first compressor and having its other end connected to the oxygen plant for providing at least a portion of the compressor discharge air to the oxygen plant;
- and,
- a return line for injecting nitrogen into the compressor discharge upstream from the air turbine.
Dependencies are inferred from the claim text.