Recuperated gas turbine engine system and method employing catalytic combustion

Claim 2

A recuperated gas turbine engine system employing catalytic combustion, comprising: a compressor arranged to receive air and to compress the air; a fuel system operable to supply fuel into the compressor, such that a mixture of compressed air and fuel is discharged from the compressor; a catalytic combustor operable to combust the mixture to produce hot combustion gases; a turbine arranged to receive the combustion gases and expand the gases to produce mechanical power that drives the compressor; a recuperator arranged to receive exhaust gases from the turbine and the mixture discharged from the compressor and cause heat exchange therebetween such that the mixture is pre-heated before entering the catalytic combustor; and a system operable to direct a portion of turbine exhaust gases into the compressor during part-load and near full-load operation of the gas turbine engine, such that the mixture discharged from the compressor is raised in temperature by said exhaust gases, whereby an inlet temperature to the catalytic combustor is raised, wherein said system comprises a valve that is controllable to variably adjust a flow rate of the exhaust gases into the compressor, and a control system operably connected to the valve.

Claim 3

The recuperated gas turbine engine system of claim 1 , wherein the control system includes a sensor operable to measure a parameter indicative of combustor inlet temperature, the control system being operable to control the valve in a manner to cause the combustor inlet temperature to exceed a predetermined minimum temperature necessary for proper operation of the catalytic combustor.

Claim 4

The recuperated gas turbine engine system of claim 1 , wherein the valve is located downstream of the recuperator such that the exhaust gases are cooled in the recuperator before being directed into the compressor.

Claim 5

The recuperated gas turbine engine system of claim 1 , wherein the valve is located upstream of the recuperator such that the portion of exhaust gas bypasses the recuperator and is then directed into the compressor.

Claim 6

The recuperated gas turbine engine system of claim 1 , further comprising an electrical generator arranged to be driven by the turbine.

Claim 7

A recuperated gas turbine engine system employing catalytic combustion, comprising: a compressor arranged to receive air and to compress the air; a fuel system operable to supply fuel into the compressor, such that a mixture of compressed air and fuel is discharged from the compressor; a catalytic combustor operable to combust the mixture to produce hot combustion gases; a turbine arranged to receive the combustion gases and expand the gases to produce mechanical power that drives the compressor; a recuperator arranged to receive exhaust gases from the turbine and the mixture discharged from the compressor and cause heat exchange therebetween such that the mixture is pre-heated before entering the catalytic combustor; and a system operable to direct a portion of turbine exhaust gases into the compressor, such that the mixture discharged from the compressor is raised in temperature by said exhaust gases, whereby an inlet temperature to the catalytic combustor is raised, wherein said system comprises a valve that is controllable to variably adjust a flow rate of the exhaust gases into the compressor, and a control system operably connected to the valve, the control system including a sensor operable to measure a parameter indicative of combustor inlet temperature, the control system being operable to control the valve in a manner to cause the combustor inlet temperature to exceed a predetermined minimum temperature necessary for proper operation of the catalytic combustor, wherein the control system further comprises a sensor operable to measure air flow rate and a sensor operable to measure fuel flow rate, and a sensor operable to measure recuperator inlet temperature, the control system operable to determine fuel/air ratio of the mixture entering the combustor based on the flow rates of air, fuel, and exhaust gases, and to control the flow rate of exhaust gases into the compressor so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that a maximum allowable recuperator temperature is not exceeded.

Claim 8

A recuperated gas turbine engine system employing catalytic combustion, comprising: a compressor arranged to receive air and to compress the air; a fuel system operable to supply fuel into the compressor, such that a mixture of compressed air and fuel is discharged from the compressor; a catalytic combustor operable to combust the mixture to produce hot combustion gases; a turbine arranged to receive the combustion gases and expand the gases to produce mechanical power that drives the compressor; a recuperator arranged to receive exhaust gases from the turbine and the mixture discharged from the compressor and cause heat exchange therebetween such that the mixture is pre-heated before entering the catalytic combustor; and a system operable to direct a portion of turbine exhaust gases into the compressor, such that the mixture discharged from the compressor is raised in temperature by said exhaust gases, whereby an inlet temperature to the catalytic combustor is raised, wherein said system comprises a valve that is controllable to variably adjust a flow rate of the exhaust gases into the compressor, and a control system operably connected to the valve, the control system including a sensor operable to measure a parameter indicative of combustor inlet temperature, the control system being operable to control the valve in a manner to cause the combustor inlet temperature to exceed a predetermined minimum temperature necessary for proper operation of the catalytic combustor, wherein the control system further comprises a sensor operable to measure air flow rate and a sensor operable to measure fuel flow rate, and a sensor operable to measure recuperator inlet temperature, the control system operable to determine fuel/air ratio of the mixture entering the combustor based on the flow rates of air, fuel, and exhaust gases, and to control the flow rate of exhaust gases into the compressor so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that a maximum allowable recuperator temperature is not exceeded.

Claim 9

The recuperated gas turbine engine system of claim 6 , wherein the control system is further operable to control the combustor inlet temperature for said fuel/air ratio in such a manner that an efficiency of the engine is maximized.

Claim 10

The recuperated gas turbine engine system of claim 7 , further comprising means for determining a level of emissions from the engine, and wherein the control system is operable to control the combustor inlet temperature for said fuel/air ratio in such a manner that a maximum allowable emissions limit is not exceeded.

Claim 11

The recuperated gas turbine engine system of claim 8 , wherein the means for determining a level of emissions comprises an emissions sensor.

Claim 12

The recuperated gas turbine engine system of claim 7 , further comprising means for determining a level of emissions from the engine, and wherein the control system is operable to control the combustor inlet temperature for said fuel/air ratio in such a manner that emissions are minimized.

Claim 15

The method of claim 11 , wherein mixing of the exhaust gases with the fuel is accomplished upstream of the compressor.

Claim 16

The method of claim 12 , wherein the mixed exhaust gases and fuel are directed into the compressor separately from the air.

Claim 17

The method of claim 11 , wherein at least some mixing of the fuel with the air is accomplished upstream of the compressor.

Claim 18

The method of claim 14 , wherein the mixed fuel and air are directed into the compressor separately from the exhaust gases.

Claim 19

The method of claim 11 , wherein the air, fuel, and exhaust gases are directed into the compressor separately from one another and mixing takes place in the compressor.

Claim 20

The method of claim 11 , further comprising the step of controlling a flow rate of the exhaust gases directed into the compressor.

Claim 21

The method of claim 17 , wherein the controlling step comprises controlling the flow rate in response to a parameter associated with the engine.

Claim 22

The method of claim 18 , wherein the controlling step comprises controlling the flow rate to compensate for changes in ambient temperature.

Claim 23

The method of claim 19 , wherein a relative portion of the exhaust gases directed into the compressor is increased when there is a decrease in ambient temperature.

Claim 24

The method of claim 18 , wherein the controlling step comprises controlling the flow rate to compensate for changes in relative engine load.

Claim 25

The method of claim 21 , wherein a relative proportion of the exhaust gases directed into the compressor is increased when there is a decrease in relative engine load.

Claim 26

The method of claim 11 , wherein the portion of exhaust gases directed into the compressor is separated from the remainder of the exhaust gases at a point downstream of the recuperator.

Claim 27

The method of claim 11 , wherein the portion of exhaust gases directed into the compressor is separated from the remainder of the exhaust gases at a point upstream of the recuperator such that said portion bypasses the recuperator.

Claim 28

The method of claim 11 , further comprising the step of driving an electrical generator with the turbine.

Claim 31

The method of claim 26 , wherein the flow rate is controlled so as to always maintain the combustor inlet temperature higher than a predetermined minimum temperature necessary for proper operation of the catalytic combustor.

Claim 32

The method of claim 27 , further comprising the step of deducing fuel/air ratio of the mixture entering the combustor, and controlling the combustor inlet temperature so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that at all times a maximum allowable recuperator temperature is not exceeded.

Claim 33

The method of claim 27 , further comprising the step of deducing fuel/air ratio of the mixture entering the combustor, and controlling the combustor inlet temperature so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that a maximum allowable emissions limit is not exceeded.

Claim 34

The method of claim 29 , further comprising the step of deducing fuel/air ratio of the mixture entering the combustor, and controlling the combustor inlet temperature so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that an efficiency of the engine is maximized.

Claim 35

The method of claim 27 , further comprising the step of deducing fuel/air ratio of the mixture entering the combustor, and controlling the combustor inlet temperature so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that emissions are minimized.

Claim 36

The method of claim 31 , further comprising the step of deducing fuel/air ratio of the mixture entering the combustor, and controlling the combustor inlet temperature so as to optimize the combustor inlet temperature for said fuel/air ratio in such a manner that efficiency is maximized.