NOx Emissions From Industrial Boilers: Potential Control Methods

1974 ◽  
Vol 96 (1) ◽  
pp. 1-6 ◽  
Author(s):  
C. W. Siegmund ◽  
D. W. Turner
Keyword(s):  
Flue Gas ◽  
Two Stage ◽  
Potential Control ◽  
Excess Air ◽  
Stage Combustion ◽  
Utility Boilers ◽  
Industrial Boilers ◽  
Potential Methods ◽  
Further Development ◽  
Methods Of Control

Future regulations may limit emissions of NOx from industrial/commercial boilers as well as utility boilers. The potential methods of control for these boilers are the same as those for utility boilers—low excess air, flue gas recycle, and two stage combustion. Low excess air and flue gas recycle can control NOx from thermal fixation. Two stage combustion controls both thermal and fuel NOx. Further development work is needed to apply these combustion modification procedures to industrial/commercial boilers in which volumetric heat release rate is normally quite high.

Reduction of Pollutant Emissions From Industrial Boilers by Combustion Modification

1977 ◽  
Vol 99 (3) ◽  
pp. 320-328 ◽  
Author(s):  
G. A. Cato ◽  
R. E. Hall ◽  
L. J. Muzio
Keyword(s):  
Flue Gas ◽  
Pollutant Emissions ◽  
Particulate Emissions ◽  
Test Program ◽  
Utility Boilers ◽  
Boiler Efficiency ◽  
Before And After ◽  
Particulate Size ◽  
Oil And Natural Gas ◽  
Industrial Boilers

The use of combustion modification has enabled many utility boilers to meet the emission standards for NOx. Its usefulness in reducing NOx emissions from industrial boilers (ranging from 11 GJ/hr to 528 GJ/hr) has been investigated during a recently completed field test program. The gaseous and particulate emissions from coal, oil, and natural-gas fuels were measured both before and after the combustion modification. Data were taken on particulate size as well as concentration. The principal combustion modification methods that were investigated included reduced excess combustion air, staged combustion air, recirculated flue gas, tuned burners, and reset burner registers. Staging was implemented by the use of overfire air ports or by turning off the fuel to some burners and increasing the fuel to others, thus creating zones of fuel-rich combustion. All of the combustion modification methods were effective to varying degrees in reducing the nitrogen oxides emissions, and reductions of as much as 50 percent were obtained with several of the modifications. In most instances the boiler efficiency was not degraded, although the particulate emissions increased by up to 50 percent in some cases. There was no substantive effect on the other pollutant emissions that were measured.

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.

Particulate Emissions From Residual Fuel Fired Boilers: Influence of Combustion Modification

1977 ◽  
Vol 99 (3) ◽  
pp. 371-377 ◽  
Author(s):  
H. L. Goldstein ◽  
C. W. Siegmund
Keyword(s):  
Size Distribution ◽  
Flue Gas ◽  
Fuel Oil ◽  
Particulate Emissions ◽  
Preheat Temperature ◽  
Flue Gas Recirculation ◽  
Residual Fuel Oil ◽  
Excess Air ◽  
Stage Combustion ◽  
Gas Recirculation

Studies were carried out in a residual fuel fired package boiler to assess the effect of various combustion modification procedures on the amount and size distribution of particulate emissions. It was found that application of moderate levels of either two stage combustion or flue gas recirculation did not have much effect on particulate loading. Severe staging as well as use of interstage heat transfer to cool the gases between stages produced significantly more particulate. Likewise, higher levels of flue gas recirculation produced substantially more particulate. In both techniques the change in size distribution was mainly in the >10- and 1–10-μm ranges. Emulsified oil containing up to 30 percent water reduced particulate loading primarily in the coarse size ranges. Satisfactory combustion could be obtained using a preheat temperature and excess air level below that required for the straight residual fuel oil.

A study of performance and emissions of SI engine with a two-stage combustion system

2011 ◽  
Vol 32 (4) ◽  
pp. 453-471 ◽  
Author(s):  
Arkadiusz Jamrozik ◽  
Wojciech Tutak
Keyword(s):  
Combustion Process ◽  
Combustion System ◽  
Si Engine ◽  
Two Stage ◽  
Lean Mixture ◽  
Engine Efficiency ◽  
Excess Air ◽  
Stage Combustion ◽  
Performance And Emissions ◽  
Test Engine

A study of performance and emissions of SI engine with a two-stage combustion systemLean mixture burning leads to a decrease in the temperature of the combustion process and it is one of the methods of limiting nitric oxide emissions. It also increases engine efficiency. An effective method to correct lean mixture combustion can be a two-stage system of stratified mixture combustion in an engine with a prechamber. This article presents the results of laboratory research on an SI engine (spark ignition) with a two-stage combustion system with a cylinder powered by gasoline and a prechamber powered by propane-butane gas LPG (liquefied petroleum gas). The results were compared to the results of research on a conventional engine with a one-stage combustion process. The test engine fuel mixture stratification method, with a two-stage combustion system in the engine with a prechamber, allowed to burn a lean mixture with an average excess air factor equal to 2.0 and thus led to lower emissions of nitrogen oxides in the exhaust of the engine. The test engine with a conventional, single-stage combustion process allowed to properly burn air-fuel mixtures of excess air factors λ not exceeding 1.5. If the value λ > 1.5, the non-repeatability factorCOVLiincreases, and the engine efficiency decreases, which makes it virtually impossible for the engine to operate. The engine with a two-stage combustion process, working with λ = 2.0, theQin/Qtot= 2.5%, reduced the NOxcontent in the exhaust gases to a level of about 1.14 g/kWh. This value is significantly lower than the value obtained in a conventional engine, which worked at λ = 1.3 with comparable non-repeatability of successive cycles (about 3%) and a similar indicated efficiency (about 34%), was characterised by the emissions of NOxin the exhaust equal to 26.26 g/kWh.

Two-stage combustion of an ultradispersed aluminum powder in air

1990 ◽  
Vol 26 (2) ◽  
pp. 190-192 ◽  
Author(s):  
A. P. Il'in ◽  
L. T. Proskurovskaya
Keyword(s):  
Aluminum Powder ◽  
Two Stage ◽  
Stage Combustion

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.

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