Low Emissions Power Generation Using Natural Gas Condensates

Author(s):  
R. Joklik ◽  
L. Eskin ◽  
M. Klassen ◽  
R. Roby ◽  
M. Holton ◽  
...  

A Lean, Premixed, Prevaporized (LPP) combustion technology has been developed that converts liquid fuels into a substitute for natural gas. This fuel can then be burned with low emissions in virtually any combustion device in place of natural gas. This technology offers the possibility of using unprocessed oil-field Natural Gas Condensate (NGC) for local or export power generation using a DLN-equipped gas turbine rather than flaring, as is common practice in some regions. The ability to run a turbine on natural gas condensate with NOx and CO emissions comparable to those of natural gas has been demonstrated using a surrogate fuel made up from a mixture of naphtha (representing C4 and greater) and methane (representing <C4). The naphtha was vaporized using an LPP system, mixed with methane, and used to generate power in a 30kW Capstone C30 microturbine. The LPP Gas™ was tailored to match the modified Wobbe Index (MWI) of methane. NOx emissions in pre-mix mode on the surrogate NGC fuel were sub 5 ppm, indistinguishable from those when running on methane. CO emissions were sub 20 ppm, comparable to those on methane. At lower loads (in diffusion mode), NOx and CO emissions on surrogate NGC-based LPP Gas™ remain comparable to those on methane. No changes were required to the DLN gas turbine combustor hardware.

Author(s):  
Leo D. Eskin ◽  
Michael S. Klassen ◽  
Richard J. Roby ◽  
Richard G. Joklik ◽  
Maclain M. Holton

A Lean, Premixed, Prevaporized (LPP) combustion technology has been developed that converts liquid biofuels, such as biodiesel or ethanol, into a substitute for natural gas. This fuel can then be burned with low emissions in virtually any combustion device in place of natural gas, providing users substantial fuel flexibility. A gas turbine utilizing the LPP combustion technology to burn biofuels creates a “dispatchable” (on-demand) renewable power generator with low criteria pollutant emissions and no net carbon emissions. Natural gas, petroleum based fuel oil #1 and #2, biodiesel and ethanol were tested in an atmospheric pressure test rig using actual gas turbine combustor hardware (designed for natural gas) and achieved natural gas level emissions. Both biodiesel and ethanol achieved natural gas level emissions for NOx, CO, SOx and particulate matter (PM). Extended lean operation was observed for all liquid fuels tested due to the wider lean flammability range for these fuels compared to natural gas. Autoignition of the fuels was controlled by the level of diluent (inerting) gas used in the vaporization process. This technology has successfully demonstrated the clean generation of green, dispatchable, renewable power on a 30kW Capstone C30 microturbine. Emissions on the vaporized derived from bio-ethanol are 3 ppm NO(x) and 18 ppm CO, improving on the baseline natural gas emissions of 3 ppm NO(x), 30 ppm CO. Performance calculations have shown that for a typical combined cycle power plant, one can expect to achieve a two percent (2%) improvement in the overall net plant heat rate when burning liquid fuel as LPP Gas™ as compared to burning the same liquid fuel in traditional spray-flame diffusion combustors. This level of heat rate improvement is quite substantial, and represents an annual fuel savings of over five million dollars for base load operation of a GE Frame 7EA combined cycle plant (126 MW). This technology provides a clean and reliable form of renewable energy using liquid biofuels that can be a primary source for power generation or be a back-up source for non-dispatchable renewable energy sources such as wind and solar. The LPP technology allows for the clean use of biofuels in combustion devices without water injection or the use of post-combustion pollution control equipment and can easily be incorporated into both new and existing gas turbine power plants. No changes are required to the DLE gas turbine combustor hardware.


Author(s):  
Richard J. Roby ◽  
Maclain M. Holton ◽  
Michael S. Klassen ◽  
Leo D. Eskin ◽  
Richard J. Joklik ◽  
...  

It is estimated that 30% of the over 1 billion cubic feet per day of natural gas produced in the Bakken shale field is lost to flaring. This flared gas, were it to be collected and used in DLE power generation gas turbine engines, represents approximately 1.2 GW of collective electric power. The main reason that much of this gas is flared is that the infrastructure in the Bakken lacks sufficient capacity or compression to combine and transport the gas streams. One of the reasons that this gas cannot be utilized on-site for power generation is that it contains significant amounts of natural gas liquids (NGLs) which make the gas unsuitable as a fuel for natural gas-fired gas turbine engines. A Lean, Premixed, Prevaporized (LPP) combustion technology has been developed that converts liquid fuels into a substitute for natural gas. This LPP Gastm can then be used to fuel virtually any combustion device in place of natural gas, yielding emissions comparable to those of ordinary natural gas. The LPP technology has been successfully demonstrated in over 1,000 hours of clean power generation on a 30 kW Capstone C30 microturbine. To date, 15 different liquid fuels have been vaporized and burned in the test gas turbine engine. To simulate the vaporization of NGLs, liquids including propane, pentane, and naphtha, among other liquids, have been vaporized and blended with methane. Emissions from the burning of these vaporized liquid fuels in the test engine have been comparable to baseline emissions from ordinary natural gas of 3 ppm NOx and 30 ppm CO. Autoignition of the vaporized liquid fuels in the gas turbine is controlled by the fraction of inert diluent added in the vaporization process. The LPP technology is able to process an infinitely variable composition of NGL components in the fuel stream by continually adjusting the amount of dilution to maintain a heating value consistent with natural gas. Burning the flare gases containing NGLs from a well locally, in a power generation gas turbine, would provide electricity for drilling operations. A microgrid can distribute power locally to the camps and infrastructure supporting the drilling and processing operations. Using the flare gases on-site has the benefit of reducing or eliminating the need for diesel tankers to supply fuel for power generation systems and equipment associated with the drilling operations.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Serhiy Serbin ◽  
Nataliia Goncharova

Investigations of the working processes in a gas turbine low-emission combustor operating on the synthesis gas, in which the principle of RQL (Rich-Burn, Quick-Mix, and Lean-Burn) combustion technology is realized, have been performed. Selected concept of a gas turbine combustor can provide higher performance and lower emission of nitrogen oxides and demonstrates satisfactory major key parameters. Obtained results and recommendations can be used for the gas turbine combustor operation modes modeling, geometry optimization, and prospective power generation units design and engineering.


Author(s):  
M. Molière ◽  
F. Geiger ◽  
E. Deramond ◽  
T. Becker

While natural gas is achieving unrivalled penetration in the power generation sector, especially in gas-turbine combined cycles (CCGT), an increasing number of alternative fuels are in a position to take up the ground left vacant by this major primary energy. In particular, within the thriving family of liquid fuels, the class of volatile products opens interesting prospects for clean and efficient power generation in CCGT plants. Therefore, it has become a necessity for the gas turbine industry to extensively evaluate such new fuel candidates, among which: naphtha’s; kerosines; gas condensates; Natural Gas Liquids (NGL) and alcohols are the most prominent representatives. From a technical standpoint, the success of such projects requires both a careful approach to several specific issues (eg: fuel handling & storage, operation safety) and a clear identification of technological limits. For instance, while the purity of gas condensates meets the requirements of heavy-duty technologies, it generally appears unsuitable for aeroderivative machines. This paper offers a succinct but comprehensive technical approach and overviews some experience acquired in this area with heavy duty gas turbines. Its aim is to inform gas turbine users/engineers and project developers who envisage volatile fuels as alternative primary energies in gas turbine plants.


Author(s):  
Takeharu Hasegawa ◽  
Tohru Hisamatsu ◽  
Yasunari Katsuki ◽  
Mikio Sato ◽  
Masahiko Yamada ◽  
...  

The development of integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future coal utilizing power generation needs. The Japanese government and the electric power industries in Japan promoted research and development of an IGCC system using an air-blown entrained-flow coal gasifier. We worked on developing a low-Btu fueled gas turbine combustor to improve the thermal efficiency of the IGCC by raising the inlet-gas temperature of gas turbine. On the other hand, Europe and the United States are now developing the oxygen-blown IGCC demonstration plants. Coal gasified fuel produced in an oxygen-blown entrained-flow coal gasifier, has a calorific value of 8.6MJ/m 3 which is one fifth that of natural gas. However, the adiabatic flame temperature of oxygen-blown medium-Btu coal gaseous fuel is higher than that of natural gas and so NOx production from nitrogen fixation is expected to increase significantly. In the oxygen-blown IGCC system, a surplus nitrogen in quantity is produced in the oxygen-production unit. When nitrogen premixed with coal gasified fuel is injected into the combustor, the power to compress nitrogen increases. A low NOx combustion technology which is capable of decreasing the power to compress nitrogen is a significant advance in gas turbine development with an oxygen-blown IGCC system. We have started to develop a low NOx combustion technology using medium-Btu coal gasified fuel produced in the oxygen-blown IGCC process. In this paper, the effect of nitrogen injected directly into the combustor on the thermal efficiency of the plant is discussed. A 1300 °C-class gas turbine combustor with a swirling nitrogen injection function designed with a stable and low NOx combustion technology was constructed and the performance of this combustor was evaluated under atmospheric pressure conditions. Analyses confirmed that the thermal efficiency of the plant improved by 0.2 percent (absolute), compared with a case where nitrogen is premixed with coal gasified fuel before injection into the combustor. Moreover, this new technique which injects nitrogen directly into the high temperature region in the combustor results in a significant reduction in NOx production from nitrogen fixation. We estimate that CO emission concentration decreases to a significant level under high pressure conditions, while CO emission concentration in contrast to NOx emission rises sharply with increases in quantity of nitrogen injected into the combustor.


Author(s):  
M. Sato ◽  
T. Ninomiya ◽  
T. Nakata ◽  
T. Yoshine ◽  
M. Yamada ◽  
...  

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low–BTU gas (LBG) which has high thermal efficiency and low emissions. In Japan a development program on the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, is planned to develop the 1300 °C class gas turbines. However, in the case of using a hot type fuel gas cleaning system, the coal gas fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel–NOx combustion technology is one of the most important research subjects. This paper describes low fuel–NOx combustion technology for 1300 °C class gas turbine combustor using low BTU coal gas fuel. Authors have showed that the rich–lean combustion method is effective to decrease fuel–NOx (1). In general in rich–lean combustion method, the fuel–NOx decreases, as the primary zone becomes richer. But flameholding becomes very difficult in even rich primary zone. For this reason this combustor was designed to have a flameholder with pilot flame. Combustion tests were conducted by using a full scale combustor used in 150 MW gas turbine at the atmospheric pressure condition.


Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.


1996 ◽  
Vol 118 (3) ◽  
pp. 201-208 ◽  
Author(s):  
S. M. Correa ◽  
I. Z. Hu ◽  
A. K. Tolpadi

Computer modeling of low-emissions gas-turbine combustors requires inclusion of finite-rate chemistry and its intractions with turbulence. The purpose of this review is to outline some recent developments in and applications of the physical models of combusting flows. The models reviewed included the sophisticated and computationally intensive velocity-composition pdf transport method, with applications shown for both a laboratory flame and for a practical gas-turbine combustor, as well as a new and computationally fast PSR-microstructure-based method, with applications shown for both premixed and nonpremixed flames. Calculations are compared with laserbased spectroscopic data where available. The review concentrates on natural-gas-fueled machines, and liquid-fueled machines operating at high power, such that spray vaporization effects can be neglected. Radiation and heat transfer is also outside the scope of this review.


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