Andrei Tristan Evulet

Application of Exhaust Gas Recirculation in a DLN F-Class Combustion System for Postcombustion Carbon Capture

This paper describes experimental work performed at General Electric, Global Research Center to evaluate the performance and understand the risks of using dry low NO x (DLN) technologies in exhaust gas recirculation (EGR) conditions. Exhaust gas recirculation is viewed as an enabling technology for increasing the CO 2 concentration of the flue gas while decreasing the volume of the postcombustion separation plant and therefore allowing a significant reduction in CO 2 capture cost. A research combustor was developed for exploring the performance of nozzles operating in low O 2 environment at representative pressures and temperatures. A series of experiments in a visually accessible test rig have been performed at gas turbine pressures and temperatures, in which inert gases such as N 2 /CO 2 were used to vitiate the fresh air to the levels determined by cycle models. Moreover, the paper discusses experimental work performed using a DLN nozzle used in GEs F-class heavy-duty gas turbines. Experimental results using a research combustor operating in a partially premixed mode include the effect of EGR on operability, efficiency, and emission performance under conditions of up to 40% EGR. Experiments performed in a fully premixed mode using a DLN single nozzle combustor revealed that further reductions in NO x could be achieved while at the same time still complying with CO emissions. While most existing studies concentrate on limitations related to the minimum oxygen concentration (MOC) at the combustor exit, we report the importance of CO 2 levels in the oxidizer. This limitation is as important as the MOC, and it varies with the pressure and firing temperatures.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Precombustion CO2 Capture

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with precombustion capture of CO 2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost, and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown partial oxidation reformer is used to generate syngas from natural gas, and a power island, in which a CO 2 -lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO 2 is removed from the shifted syngas using either CO 2 absorbing solvents or a CO 2 membrane. CO 2 separation membranes, in particular, have the potential for considerable cost or energy savings compared with conventional solvent-based separation and benefit from the high-pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short-term and long-term solutions have been investigated. An analysis of the cost of CO 2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO 2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO 2 capture, as well as the cost target of 30

Effect of Exhaust Gas Recirculation on NOx Formation in Premixed Combustion System

per ton of CO 2 avoided (2006 Ql basis). This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Pre-Combustion CO2 Capture

*† ‡ Exhaust gas recirculation (EGR) is an enabling technology to reduce CO2 capture cost for gas-turbine-based power plants. Experiments performed in fully premixed mode using Dry Low NOx single nozzle combustor at General Electric Global Research Center also revealed NOx reduction at same flame temperature by EGR. This paper presents systematic chemical kinetics analysis to study the effect of EGR on NOx formation in lean premixed combustion system under gas turbine representative temperatures and pressures. Simulation results are first presented for perfectly premixed combustion system to study the effect of EGR at different pressures (1-30 atm), oxidizer compositions, and EGR ratios. Based on detailed analysis, dominant mechanisms responsible for NOx formation are identified for different pressures. The effect of fuel-air unmixedness is then introduced to model the industrial gas turbine combustors. It is found that NOx formation is much less sensitive to the unmixedness with EGR than the baseline case. For typical gas turbine combustors, EGR introduces large benefits (up to 50%) for raw NOx reduction at same flame temperature, and even larger reduction if NOx concentration is corrected to 15% O2.

Performance and Cost Analysis of a Novel Gas Turbine Cycle With CO2 Capture

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with pre-combustion capture of CO2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown POX reformer is used to generate syngas from natural gas, and a power island, in which a CO2 -lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO2 is removed from the shifted syngas using either CO2 absorbing solvents or a CO2 membrane. CO2 separation membranes, in particular, have the potential for considerable cost or energy savings compared to conventional solvent-based separation and benefit from the high pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short term and long term solutions have been investigated. An analysis of the cost of CO2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO2 capture, as well as the cost target of 30

Exhaust Gas Recirculation in DLN F-Class Gas Turbines for Post-Combustion CO

per ton of CO2 avoided. This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.Copyright

Systems and methods for power generation with exhaust gas recirculation

In this paper, a new gas turbine cycle with integrated post-combustion CO2 capture is presented. The concept advantageously uses an intercooled gas turbine in combination with exhaust gas recirculation to enable CO2 separation at elevated concentration and pressure. Therefore, less energy is required for the CO2 separation process. In addition, due to the reduced volume flow entering the CO2 separation unit, the costs of the CO2 separation equipment are significantly reduced. The performance and cost of CO2 avoided of the power cycle have been analyzed. The results show that the concept is able to reach high CO2 capture rates of 80% and above. When accounting for CO2 capture and compression, nearly 50% (LHV) combined cycle net efficiency is obtained based on an existing medium scale intercooled gas turbine. Furthermore, the cycle has an even higher efficiency potential if applied to larger intercooled gas turbine combined cycles in the future. Using CO2 separation membrane technology which is currently under development, the cost of CO2 avoided is estimated at 31

LOW EMISSION TURBINE SYSTEM AND METHOD

/tCO2 based on a medium scale intercooled gas turbine. A future scaled-up configuration based on a large-frame intercooled gas turbine has the potential to meet 30

System and method of improving emission performance of a gas turbine

/tCO2 cost of CO2 avoided.Copyright

On the Performance and Operability of GE’s Dry Low NOx Combustors utilizing Exhaust Gas Recirculation for PostCombustion Carbon Capture

This paper describes experimental work performed at General Electric, Global Research Center to evaluate the performance and understand the risks of using Dry Low NOx (DLN) technologies in Exhaust Gas Recirculation (EGR) conditions. Exhaust Gas Recirculation is viewed as an enabling technology for increasing the CO2 concentration of the flue gas while decreasing the volume of the post-combustion separation plant and therefore allowing a significant reduction in CO2 capture cost. A research combustor was developed for exploring the performance of nozzles operating in low O2 environment at representative pressures and temperatures. A series of experiments in a visually accessible test rig have been performed at gas turbine pressures and temperatures, in which inert gases such as N2 /CO2 were used to vitiate the fresh air to the levels determined by cycle models. Moreover, the paper will discuss experimental work performed using a DLN nozzle used in GE’s F-class heavy-duty gas turbines. Experimental results using a research combustor operating in partially premixed mode, incorporate the effect of applying EGR on operability, efficiency and emissions performance under conditions of up to 40% EGR. Experiments performed in fully premixed mode using DLN single nozzle combustor revealed that further reductions in NOx could be achieved and at the same time still complying with CO emissions. While most existing studies concentrate on limitations related to the Minimum Oxygen Concentration (MOC) at the combustor exit, we report the importance of CO2 levels in the oxidizer. This limitation is as important as the MOC and it varies with the pressure and firing temperatures.© 2008 ASME