scholarly journals USE OF TWO-STAGE FUEL COMBUSTION TECHNOLOGY TO MINIMIZE HAZARDOUS EMISSIONS AT KAZAKHSTAN TPP

2021 ◽  
Vol 335 (1) ◽  
pp. 74-80
Author(s):  
A.S. Askarova ◽  
P. Safarik ◽  
S.A. Bolegenova ◽  
V.Yu. Maximov ◽  
A.O. Nugymanova ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Mass Transfer Process ◽  
Fuel Combustion ◽  
Low Grade ◽  
Two Stage ◽  
Entire Volume ◽  
Coal Fuel ◽  
Air Supply ◽  
Stage Combustion ◽  
Combustion Technology

Studies have been carried out using numerical modeling methods to determine the effect of the introduction of a two-stage combustion technology (OFA technology) of high-ash Karaganda coal on the characteristics of combustion processes: aerodynamics of flows, temperature and concentration (COх, NOх) fields throughout the entire volume of the combustion chamber of the BKZ-75 boiler at Shakhtinskaya TPP and at the outlet from it. Comparison with the basic regime of combustion of pulverized coal fuel, when there is no air supply through additional injectors (OFA = 0%). To implement the technology of two-stage combustion, various regimes of additional air supply through injectors were chosen: OFA equals 0% (basic version, conventional combustion), 5%, 10%, 15%, 18%, 20%, 25% and 30% of total air volume required for fuel combustion. A comparative analysis of the main characteristics of the heat and mass transfer process in the combustion chamber for the investigated modes is carried out. It is shown that an increase in the volume of additional air supplied through the injectors up to 18% leads to a decrease in the concentration of nitrogen oxide NO by 25% in comparison with traditional combustion. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the combustion chamber of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions and introduce a two-stage combustion technology at other coal-fired TPPs.

USE OF TWO-STAGE FUEL COMBUSTION TECHNOLOGY TO MINIMIZE HAZARDOUS EMISSIONS AT KAZAKHSTAN TPP

2021 ◽  
Vol 335 (1) ◽  
pp. 74-80
Author(s):  
A.S. Askarova ◽  
P. Safarik ◽  
S.A. Bolegenova ◽  
V.Yu. Maximov ◽  
A.O. Nugymanova ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Mass Transfer Process ◽  
Fuel Combustion ◽  
Low Grade ◽  
Two Stage ◽  
Entire Volume ◽  
Coal Fuel ◽  
Air Supply ◽  
Stage Combustion ◽  
Combustion Technology

Studies have been carried out using numerical modeling methods to determine the effect of the introduction of a two-stage combustion technology (OFA technology) of high-ash Karaganda coal on the characteristics of combustion processes: aerodynamics of flows, temperature and concentration (COх, NOх) fields throughout the entire volume of the combustion chamber of the BKZ-75 boiler at Shakhtinskaya TPP and at the outlet from it. Comparison with the basic regime of combustion of pulverized coal fuel, when there is no air supply through additional injectors (OFA = 0%). To implement the technology of two-stage combustion, various regimes of additional air supply through injectors were chosen: OFA equals 0% (basic version, conventional combustion), 5%, 10%, 15%, 18%, 20%, 25% and 30% of total air volume required for fuel combustion. A comparative analysis of the main characteristics of the heat and mass transfer process in the combustion chamber for the investigated modes is carried out. It is shown that an increase in the volume of additional air supplied through the injectors up to 18% leads to a decrease in the concentration of nitrogen oxide NO by 25% in comparison with traditional combustion. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the combustion chamber of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions and introduce a two-stage combustion technology at other coal-fired TPPs.

scholarly journals Computer Technologies of 3D Modeling by Combustion Processes to Create Effective Methods of Burning Solid Fuel and Reduce Harmful Dust and Gas Emissions into the Atmosphere

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1236
Author(s):  
Aliya Askarova ◽  
Saltanat Bolegenova ◽  
Valeriy Maximov ◽  
Symbat Bolegenova ◽  
Nariman Askarov ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Dioxide ◽  
Combustion Products ◽  
Temperature Fields ◽  
Base Case ◽  
Low Grade ◽  
Two Stage ◽  
Entire Volume ◽  
Stage Combustion ◽  
Combustion Technology

Using numerical methods, studies have been carried out to determine the effect of the introduction of the technology of two-stage combustion of high-ash Karaganda coal on the main characteristics of heat and mass transfer processes in the furnace of the BKZ-75 boiler at Shakhtinskaya TPP (Kazakhstan). Various regimes of supplying additional air into the combustion space, the volume of which varied from 0% (traditional basic version) to 30% of the total volume of air required for fuel combustion, have been investigated using 3D computer modeling methods. The performed computational experiments made it possible to obtain the distributions of the total velocity vector, temperature fields, concentration fields of carbon monoxide CO and nitrogen dioxide NO2 over the entire volume of the furnace and at the outlet from it. The introduction of the two-stage combustion technology made it possible to optimize the combustion of high-ash coal, since in this case there is an increase in the temperature in the torch core and a decrease in it at the outlet from the furnace, which has a significant effect on the chemical processes of the formation of combustion products. Based on the results obtained, it can be concluded that an increase in the percentage of air supplied through additional injectors to 18% leads to a decrease in the concentrations of carbon monoxide CO by about 36%, and nitrogen dioxide NO2 by 25% compared to the base case. A further increase in the volume of additional air leads to a deterioration in these indicators. The results obtained will make it possible to optimize the combustion of low-grade fuel in the furnace of the BKZ-75 boiler, increase the efficiency of fuel burnout, reduce harmful emissions into the atmosphere, and introduce a two-stage combustion technology at other coal-fired TPPs.

Study of Medium-Btu Fueled Gas Turbine Combustion Technology for Reducing Both Fuel-NOx and Thermal-NOx Emissions in Oxygen-Blown IGCC

2002 ◽  
Author(s):  
Takeharu Hasegawa ◽  
Mikio Sato ◽  
Yasunari Katsuki ◽  
Tohru Hisamatsu
Keyword(s):  
Direct Injection ◽  
Combustion Method ◽  
Nox Emission ◽  
Two Stage ◽  
Gas Cleaning ◽  
Stage Combustion ◽  
Combustion Technology ◽  
Thermal Nox ◽  
Combustion Tests ◽  
Fuel Nox

In order to improve the thermal efficiency of the oxygen-blown IGCC (Integrated Gasification Combined Cycle) for stricter environmental standards and cost-effective option, it is necessary to adopt the hot/dry gas cleaning system. In this system, the flame temperature of medium-btu gasified fuel is higher and so NOx production from nitrogen fixation is expected to increase significantly. Also the gasified fuel contains fuel nitrogen, such as ammonia, in the case of employing the hot/dry gas cleaning system. This ammonia is easily oxidized into fuel-NOx in the combustor. For contribution to the protection of the environment and low cost operations of all kinds of oxygen-blown IGCC, low NOx combustion technology for reducing both the fuel-NOx and thermal-NOx emission has to be developed. In this paper, we clarified effectiveness of applying both the two-stage combustion and the nitrogen injection, and the useful engineering guidelines for the low-NOx combustor design of oxygen-blown gasified, medium-btu fuels. Main results obtained are as follows: (1) Based on the fundamental combustion tests using the small diffusion burner, we clarified that equivalence ratio at the primary combustion zone has to be adjusted due to the fuel conditions, such as methane concentration, CO/H2 molar ratio, and calorific values of gasified fuels in the case of the two-stage combustion method for reducing fuel-NOx emission. (2) From the combustion tests of the medium-btu fueled combustor the two-stage combustion with nitrogen direct injection into the combustor results in reduction of NOx emission to 80ppm (corrected at 16% O2) or less, the conversion rate of ammonia to NOx was 35% under the gas turbine operational conditions for IGCC in the case where fuel contains 3% of methane and 2135ppm of ammonia. By means of nitrogen direct injection, the thermal efficiency of the plant improved by approximately 0.3 percent (absolute), compared with a case where nitrogen is premixed with gasified fuel. The CO emission concentration decreased drastically, as low as 20ppm, or combustion efficiency was kept higher than 99.9%. Furthermore, based on the fundamental combustion tests’ results, the ammonia conversion rate is expected to decrease to 16% and NOx emission to 26ppm in the case of gasified fuel that contains 0.1% methane and 500ppm of ammonia. From the above results, it is clarified that two-stage combustion method with nitrogen injection is very effective for reducing both the fuel-NOx and thermal-NOx emissions at once in IGCC and it shows the bright prospects for low NOx and stable combustion technology of the medium-btu fuel.

Study of Sequential Two-Stage Combustion in a Low-Emission Gas Turbine Combustion Chamber

2018 ◽  
Vol 65 (11) ◽  
pp. 806-817 ◽  
Author(s):  
L. A. Bulysova ◽  
A. L. Berne ◽  
V. D. Vasil’ev ◽  
M. N. Gutnik ◽  
M. M. Gutnik
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Two Stage ◽  
Stage Combustion ◽  
Low Emission ◽  
Gas Turbine Combustion

Combustion Technology in a Novel Gas Turbine System with Steam Injection and Two-Stage Combustion.

2001 ◽  
Vol 34 (9) ◽  
pp. 1159-1164 ◽  
Author(s):  
DAIQING ZHAO ◽  
YUKI OHNO ◽  
TOMOHIKO FURUHATA ◽  
HIROSHI YAMASHITA ◽  
NORIO ARAI ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Steam Injection ◽  
Two Stage ◽  
Stage Combustion ◽  
Combustion Technology

Gas Turbine Combustion Technology Reducing Both Fuel-NOx and Thermal-NOx Emissions for Oxygen-Blown IGCC With Hot/Dry Synthetic Gas Cleanup

2006 ◽  
Vol 129 (2) ◽  
pp. 358-369 ◽  
Author(s):  
Takeharu Hasegawa ◽  
Takashi Tamaru
Keyword(s):  
Direct Injection ◽  
Combustion Method ◽  
Nox Emissions ◽  
Two Stage ◽  
Stage Combustion ◽  
Synthetic Gas ◽  
Combustion Technology ◽  
Thermal Nox ◽  
Combustion Tests ◽  
Fuel Nox

In order to improve the thermal efficiency of the oxygen-blown integrated gasification combined cycle (IGCC) and to meet stricter environmental restrictions among cost-effective options, a hot/dry synthetic gas cleanup is one of the most hopeful choices. The flame temperature of medium-Btu gasified fuel used in this system is high so that NOx formation by nitrogen fixation results to increase significantly. Additionally, the gasified fuel contains nitrogenous compound, as ammonia, and it produces nitrogen oxides, the fuel NOx, in the case of employing the hot/dry gas cleanup. Low NOx combustion technology to reduce both fuel-NOx and thermal-NOx emissions has been required to protect the environment and ensure low cost operations for all kinds of oxygen-blown IGCC. In this paper, we have demonstrated the effectiveness of two-stage combustion and nitrogen injection techniques, and also showed engineering guidelines for the low-NOx combustor design of oxygen-blown gasified, medium-Btu fuels. The main results obtained are as follows: (1) Based on the basic combustion tests using a small diffusion burner, we clarified that the equivalence ratio at the primary combustion zone has to be adjusted according to the fuel conditions, such as methane concentration, CO∕H2 molar ratio, and calorific values of gasified fuels in the case of the two-stage combustion method for reducing fuel-NOx emissions. (2) From the combustion tests of the medium-Btu fueled combustor, two-stage combustion with nitrogen direct injection into the combustor results in reductions of NOx emissions to 34ppm (corrected at 16% O2) or less under the gas turbine operational conditions of 25% load or higher for IGCC in the case where the gasified fuel contains 0.1% methane and 500ppm of ammonia. Through nitrogen direct injection, the thermal efficiency of the plant improved by approximately 0.3% (absolute), compared with the case where nitrogen was premixed with gasified fuel. The CO emission concentration decreased drastically, as low as 20ppm, or combustion efficiency was kept higher than 99.9%. The above results have shown that a two-stage combustion method with nitrogen direct injection is very effective for reducing both fuel-NOx and thermal-NOx emissions at once in IGCC, and it shows the bright prospects for low NOx and stable combustion technology of medium-Btu fuel.

CFD: Analysis of the Influence of Modified Tangential Air Inlets on the Combustion Behavior of a Two-Stage Combustion Chamber

2004 ◽  
Author(s):  
Klaus Hoerzer ◽  
Hermann Haselbacher
Keyword(s):  
Combustion Chamber ◽  
Flue Gas ◽  
Wood Dust ◽  
Parameter Study ◽  
Cfd Analysis ◽  
Two Stage ◽  
Combustion Performance ◽  
University Of Technology ◽  
Stage Combustion ◽  
Operation Parameters

At the Institute of Thermal Turbomachines and Powerplants at the Vienna University of Technology, a two-stage combustion chamber was designed and constructed to directly drive a gas turbine by combustion of wood dust. A commercial CFD-solver was applied to examine the effects of modifications of the geometry on the combustion performance. Since this parameter study was done with the same operation parameters and the same boundary conditions, the computational results represent the influence of the different flow fields caused by the modified combustion chamber. The particle gasification time, the temperature, and the chemical composition of the flue gas at the combustion chamber exit have been used for the assessment of the combustion performance.

scholarly journals Analysis of Two-Stage Fuel Combustion in Multi-Fuel Boilers

2021 ◽  
pp. 33-37
Author(s):  
Vadym Dyahiliev ◽  
Olexander Yefimov ◽  
Valerii Kavertsev ◽  
Tetyana Harkusha ◽  
Bogdan Chernysh
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Combustion Products ◽  
Fuel Combustion ◽  
Fuel Oil ◽  
Toxic Substances ◽  
Two Stage ◽  
Boiler Load ◽  
Stage Combustion ◽  
Combustion Processes

The significant growth of industry in the second half of the 20th century led to a number of problems, one of the most important problems is the protection of the environment from pollution. The main source of air pollution is heat and power generating plants, which are based on combustion processes. The largest pollutant is thermal power plants, which burn a large volume of fossil fuel and form a corresponding amount of toxic substances, in particular nitrogen and sulfur oxides. In this paper, combustion processes with various burner devices will be considered and two fuels – natural gas, fuel oil. One of the most important tasks operation of power equipment is the development and widespread use of effective methods to reduce the formation of harmful substances and determining the optimal modes of fuel combustion, ensuring a minimum level of emissions of toxic combustion products. Two-stage fuel combustion is an effective method of reducing nitrogen oxide emissions. In two-stage combustion, one fuel burnout zone is replaced by several zones, as isolated as possible. The paper will compare several options for the implementation of two-stage combustion in the boiler. The influence of boiler load on the concentration of nitrogen oxides in the exhaust gases is analyzed. Also at two-stage combustion of fuel oil in gas-oil boilers reliability of screen surfaces of heating as a result of decrease in the maximum falling heat streams on a screen surface of heating of a copper increased.

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