Combustion Performance in a Semiclosed Cycle Gas Turbine for IGCC Fired With CO-Rich Syngas and Oxy-Recirculated Exhaust Streams

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Takeharu Hasegawa
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Combustion Process ◽  
Equilibrium Concentration ◽  
Combined Cycle ◽  
Reaction Heat ◽  
Highly Efficient ◽  
Coal Fuel ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Our study found that burning a CO-rich gasified coal fuel, derived from an oxygen–CO2 blown gasifier, with oxygen under stoichiometric conditions in a closed cycle gas turbine produced a highly-efficient, oxy-fuel integrated coal gasification combined cycle (IGCC) power generation system with CO2 capture. We diluted stoichiometric combustion with recycled gas turbine exhaust and adjusted for given temperatures. Some of the exhaust was used to feed coal into the gasifier. In doing so, we found it necessary to minimize not only CO and H2 of unburned fuel constituents but also residual O2, not consumed in the gas turbine combustion process. In this study, we examined the emission characteristics of gasified-fueled stoichiometric combustion with oxygen through numerical analysis based on reaction kinetics. Furthermore, we investigated the reaction characteristics of reactant gases of CO, H2, and O2 remaining in the recirculating gas turbine exhaust using present numerical procedures. As a result, we were able to clarify that since fuel oxidation reaction is inhibited due to reasons of exhaust recirculation and lower oxygen partial pressure, CO oxidization is very sluggish and combustion reaction does not reach equilibrium at the combustor exit. In the case of a combustor exhaust temperature of 1573 K (1300 °C), we estimated that high CO exhaust emissions of about a few percent, in tens of milliseconds, corresponded to the combustion gas residence time in the gas turbine combustor. Combustion efficiency was estimated to reach only about 76%, which was a lower value compared to H2/O2-fired combustion while residual O2 in exhaust was 2.5 vol%, or five times as much as the equilibrium concentration. On the other hand, unburned constituents in an expansion turbine exhaust were slowed to oxidize in a heat recovery steam generator (HRSG) flue processing, and exhaust gases reached equilibrium conditions. In this regard, however, reaction heat in HRSG could not devote enough energy for combined cycle thermal efficiency, making advanced combustion technology necessary for achieving highly efficient, oxy-fuel IGCC.

Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating On Hydrogen and Natural Gas Blends

2021 ◽  
Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Model ◽  
Computational Domain ◽  
Cfd Model ◽  
Exhaust Duct ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.

Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines

1989 ◽  
Author(s):  
Lothar Bachmann ◽  
W. Fred Koch
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Operating Conditions ◽  
High Mass ◽  
Expansion Joints ◽  
Gas Turbine Exhaust ◽  
New Generation ◽  
Turbine Exhaust

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.

Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating on Hydrogen and Natural Gas Blends

2021 ◽  
Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Model ◽  
Computational Domain ◽  
Cfd Model ◽  
Exhaust Duct ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.

Conversion of Sulfur Dioxide to Sulfur Trioxide in Gas Turbine Exhaust

1990 ◽  
Vol 112 (4) ◽  
pp. 585-589 ◽  
Author(s):  
B. W. Harris
Keyword(s):  
Gas Turbine ◽  
Life Time ◽  
Combined Cycle ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Boiler Tubes ◽  
Cycle Systems ◽  
Marine Diesel ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Acid dewpoints were calculated from SO2-to-SO3 conversion in gas turbine exhaust. These data can be used as guidelines in setting feedwater temperatures in combined-cycle systems. Accurate settings can prevent corrosion of heat-exchanger (boiler) tubes, thus extending their life time. This study was done using gas turbine engines and a laboratory generator set. The units burned marine diesel or diesel No. 2 fuel with sulfur contents up to 1.3 percent. The exhaust from these systems contained an excess of 20 percent oxygen, and 3–10 percent water vapor. Exhaust temperatures ranged from 728 to 893 K (455 to 620°C).

Gas Turbine Performance Using Carbon Dioxide as Working Fluid in Closed Cycle Operation

2000 ◽  
Author(s):  
Anthony J. B. Jackson ◽  
Alcides Codeceira Neto ◽  
Matthew W. Whellens ◽  
Harry Audus
Keyword(s):  
Carbon Dioxide ◽  
Gas Turbine ◽  
Combustion Process ◽  
Working Fluid ◽  
Closed Cycle ◽  
Engine Exhaust ◽  
World Demand ◽  
Gas Turbine Exhaust ◽  
Carbon Dioxide Co2 ◽  
Turbine Exhaust

The world’s main atmospheric “greenhouse gas” is carbon dioxide (CO2). The CO2 content of the atmosphere continues to rise due to increasing world demand for energy, and thus further means are needed to achieve its abatement. Most gas turbine powered electricity generating plants use hydro-carbon fuels and this inevitably produces CO2 in the engine exhaust. This paper discusses a scheme for concentrating the gas turbine exhaust CO2, thus facilitating its extraction. The scheme is a gas turbine operating synchronously in closed cycle, with CO2 as the working fluid. The additional CO2 and water produced in the combustion process are removed continuously. CO2 and air have substantially different gas properties. This significantly affects the performance of the gas turbine. It is shown that any gas turbine designed to use air, and operating synchronously, would need considerable modifications to its compressor and combustion systems to use carbon dioxide as its working fluid.

Mild Combustion in a Novel CCGT Cycle With Partial Flue Gas Recirculation

2003 ◽  
Author(s):  
S. M. Camporeale ◽  
F. Casalini ◽  
A. Saponaro
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Soot Formation ◽  
Combustion Process ◽  
Combined Cycle ◽  
Pollutant Emissions ◽  
Inlet Temperature ◽  
Heavy Fuel Oil ◽  
Mild Combustion ◽  
Turbine Exhaust

A novel Combined Cycle Gas Turbine layout is proposed for using heavy fuel oil in a combustion mode called “Mild Combustion”, characterized by a very low adiabatic flame temperature and flat temperature field in the combustion chamber and low pollutant emissions. “Mild Combustion” is obtained by means of the dilution of reactants with inert gas like combustion product resulting in a very low oxygen concentration of the mixture at the ignition. To stabilize the combustion process in such a condition the reactants temperature has to be raised above the self ignition value. In industrial application this particular preconditioning of the reactants can be reached partially before the combustion chamber and finally in process by means of a performed aerodynamic that further dilute and heat-up the mixture. An experimental analysis of the oil combustion behaviour inside the gas turbine exhaust flow has been arranged at Centro Combustione of Ansaldo Caldaie in Gioia del Colle (Italy). The turbine exhaust gases are simulated by mixing those produced in a gas burner with external air preheated at different temperatures in order to have different final oxygen concentrations and temperature levels. The influence of the main combustion parameters regarding the process feasibility and environmental impact are presented and analysed. Good results in terms of NOx emissions and soot formation have been obtained for heavy oil combustion in a 10% oxygen oxidizer concentration requiring a combustion chamber inlet temperature of about 900K. In order to meet these conditions, a novel CCGT cycle in which about 64% of combustion products are re-circulated before entering the combustion chamber, is proposed. The thermodynamic analysis shows that the efficiency that could be achieved by the proposed cycle is a few percent lower than the efficiency of a combined cycle power plant fuelling natural gas, with the same turbine inlet temperature and similar turbine blade cooling technology.

scholarly journals Design and Operating Experiences With Gas Turbine Combined Cycle Units

1971 ◽  
Author(s):  
R. W. Jones ◽  
A. C. Shoults
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Economic Factors ◽  
Chemical Company ◽  
Gas Turbine Exhaust ◽  
Selection Of ◽  
Turbine Exhaust

This paper presents details of three large gas turbine installations in the Freeport, Texas, power plants of the Dow Chemical Company. The general plant layout, integration of useful outputs, economic factors leading to the selection of these units, and experiences during startup and operation will be reviewed. All three units operate with supercharging fan, evaporative cooler, and static excitation. Two of the installations are nearly identical 32,000-kw gas turbines operating in a combined cycle with a supplementary fired 1,500,000-lb/hr boiler and a 50,000-kw noncondensing steam turbine. The other installation is a 43,000-kw gas turbine and a 20,000-kw starter-helper steam turbine on the same shaft. The gas turbine exhaust is used to supply heated feedwater for four existing boilers.

scholarly journals Multiple Evaporation Steam Bottoming Cycle

1997 ◽  
Author(s):  
H. Jericha ◽  
M. Fesharaki ◽  
A. Seyr
Keyword(s):  
Gas Turbine ◽  
Steam Line ◽  
Combined Cycle ◽  
Steam Flow ◽  
Feed Water ◽  
Exhaust Gas ◽  
Gas Cooling ◽  
Gas Turbine Exhaust ◽  
Cycle Efficiency ◽  
Turbine Exhaust

Improvements to the steam bottoming cycles hold the promise of raising the combined cycle thermal efficiency to values near and above 60%. Up to now, steam bottoming cycles with three pressure levels of steam evaporation have been realised. A further advantage seems possible by the use of double fluids, such as mixtures of steam and ammonia. In the cycle proposed here, the authors limit Themselves to the use of steam and water only, in order to avoid all the difficulties, that may arise from such mixtures. The solution given here, relies on multiple evaporation levels, more than three up to five and even more. They should be to be achieved with the help of newly developed steam turbochargers, which allow the unification of the steam flow from three different neighbouring pressure levels, into one steam flow to be transmitted via the live steam line to the main turbine. This large number of evaporation levels, together with the required economisers for feed water heating and the ensuing superheaters arranged in the proper way, gives a steam water heat acceptance curve, which can be closely matched to the exhaust gas cooling line, so that the heat transfer from the gas turbine exhaust to the steam bottoming cycle can be effected with a minimum of temperature differences. It should be pointed out that the steam pressures are selected in the undercritical region, and that a total combined cycle efficiency very near to 60% can be achieved. Using most modern gas turbine models together with this novel bottoming cycle will even allow to exceed the value of 60%. Examples given have been calculated for standard gas turbine models.

Gas Turbine Exhaust Energy Margin in a Combined Cycle Power Plant

2002 ◽  
Author(s):  
Paul B. Johnston
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Risk Mitigation ◽  
Field Testing ◽  
Combined Cycle ◽  
Plant Performance ◽  
Performance Guarantees ◽  
Exhaust Energy ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Margining gas turbine exhaust energy exposes the EPC (Engineering, Procurement & Construction) contractor to risk when developing overall plant performance guarantees. The objective of this paper is to explain the nature of this risk, recognize its significance and propose ways of mitigation. Sharing risk between the Developer and the contractor should be apportioned to maximize value for the project. Attention is focused on 2 on 1 combined cycle power plants, but the results are relevant for all types of gas turbine based power and cogeneration facilities. Risk mitigation alternatives discussed include both assessment of margins to the bottomline performance and the application of performance corrections at the time of field testing. Allowing for corrections leads to enhanced overall plant performance guarantees.

Reaction of Fuel NOx Formation for Gas Turbine Conditions

1998 ◽  
Vol 120 (3) ◽  
pp. 474-480 ◽  
Author(s):  
T. Nakata ◽  
M. Sato ◽  
T. Hasegawa
Keyword(s):  
Gas Turbine ◽  
Coal Gasification ◽  
Combustion Process ◽  
Combined Cycle ◽  
Inlet Section ◽  
Mixing Condition ◽  
Nox Formation ◽  
Air Inlet ◽  
Secondary Air ◽  
Fuel Nox

Ammonia contained in coal-gasified fuel is converted to nitrogen oxides (NOx) in the combustion process of a gas turbine in integrated coal gasification combined cycle (IGCC) system. Research data on fuel-NOx formation are insufficient, and there still remains a wide explored domain. The present research aims at obtaining fundamental knowledge of fuel-NOx formation characteristics by applying reaction kinetics to gas turbine conditions. An instantaneous mixing condition was assumed in the cross section of a gas turbine combustor and both gradual mixing condition and instantaneous mixing condition were assumed at secondary air inlet section. The results may be summarized as follows: (1) in the primary combustion zone under fuel rich condition, HCN and other intermediate products are formed as ammonia contained in the fuel decomposes; (2) formation characteristics of fuel-NOx are affected by the condition of secondary air mixing; and (3) the conversion ratio from ammonia to NOx declines as the pressure inside the combustor rises under the condition of gradual mixing at the secondary air inlet. These results obtained agreed approximately with the experimentation.

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