Arne Lynghjem

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 a Novel Gas Turbine Cycle With CO2 Capture

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

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

/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

The Offshore Application of a Dual-Mode Injection Centrifugal Compressor and Improvements to Rotating Stall

/tCO2 cost of CO2 avoided.Copyright

Operational Experience and Energy-Saving Improvements on Offshore Gas Turbine Driven Compressor Trains

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

Efficient combined cycle power plant with co2 capture and a combustor arrangement with separate flows

This paper covers the experience from the retrofit of a new dual-mode injection compressor into the existing gas compression facilities on an offshore platform. The implementation of this new and innovative compressor technology made it possible to fulfil new requirements to higher throughput, different kind of service, improved safety level and economical operation.But then the compressor exhibited gas dynamic instability — determined as rotating stall in the impeller — a phenomenon not well understood. The literature on this topic is scare. The rotating stall phenomenon caused a significant reduction in useful operational area of the compressor. An improvement program was carried out. Changes in the impeller geometry led to restoration of the expected operational range. The magnitude of the phenomenon has diminished partially also. Rotating stall criteria proved to be useful in order to improve or avoid rotating stall problems in a centrifugal compressor.The dual-mode injection compressor allowed decommissioning of a whole equipment module, which represents a very useful experience factor in the design of new offshore platforms. The compressor has been in operation since November 1994, and it has been able to fulfil all specified operating requirements.Copyright

Exhaust Gas Recirculation in DLN F-Class Gas Turbines for Post-Combustion CO2 Capture

The efficient operation of offshore gas turbine driven compressor trains is becoming more and more important. With the introduction of the CO2 tax on fuelgas in Norway, the operating costs have dramatically changed. It is now necessary to focus on energy-saving operation and maintenance in order to include the influence of CO2 taxation. In the Statfjord and Gullfaks fields, the LM2500 high efficiency aeroderivative gasturbines have been in operation for several years, and the operational experience is presented and discussed here with regard to efficiency and reliability. An optimised gas turbine maintenance program has been introduced in order to obtain energy-saving and cost reduction. The problems relating to the gas compression trains are discussed with regard to energy conservation and reliability. Off design operating conditions on compressors have caused problems, both with regard to power losses and machinery safeguard control systems. Energy-saving improvements have been implemented on the compressors and the system they are working in. The reliable operation of the compressors can be put at risk by the shaft-sealing system. It is of vital importance to ensure correct operation of seal system in order to obtain safe and economical operation. Improvements to shaft-sealing systems are discussed.Copyright