Combining Fuel Rich/Lean Burner With the Small Heavy Oil Gun Ignition Techniques Makes Pulverized Coal-Fired Boiler More Efficient

2011 ◽  
Author(s):  
Guiyuan Mo ◽  
Hao Zhou ◽  
Feng Chen ◽  
Hong Yin ◽  
Kunzan Qiu ◽  
...  
Keyword(s):  
Heavy Oil ◽  
Pulverized Coal ◽  
Operating Conditions ◽  
Flame Stability ◽  
Fusion Temperature ◽  
Detailed Design ◽  
Utility Boiler ◽  
Start Up ◽  
Ash Fusion Temperature ◽  
Low Load

The coal qualities changes very frequently in China, to make the flame stability under different operating conditions is difficult and it is important to prevent the furnace from the serious slagging while the coals with low ash fusion temperature are combusted, at the same time, the utility units now face the frequent load changing, how to save the oil at the low load or during the start up period becomes a very serious problem. In this work, the burner combing the fuel rich/lean separator and the small heavy oil gun ignition techniques were developed and then employed in a utility boiler. The detailed design of such a novel burner is introduced in this paper. Such a burner can achieve a 50% rated load and 70% heavy oil can be saved.

Numerical study of pulverized coal-fired utility boiler over a wide range of operating conditions for in-furnace SO2/NOx reduction

2016 ◽  
Vol 94 ◽  
pp. 657-669 ◽  
Author(s):  
Srdjan Belošević ◽  
Ivan Tomanović ◽  
Nenad Crnomarković ◽  
Aleksandar Milićević ◽  
Dragan Tucaković
Keyword(s):  
Numerical Study ◽  
Nox Reduction ◽  
Pulverized Coal ◽  
Operating Conditions ◽  
Utility Boiler ◽  
Wide Range

Stratified and hydrogen combustion techniques for higher turndown and lower emissions in gas turbines

2021 ◽  
pp. 1-42
Author(s):  
Medhat A. Nemitallah ◽  
Md Azazul Haque ◽  
Muzafar Hussain ◽  
Ahmed Abdelhafez ◽  
Mohamed A. Habib
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Hydrogen Gas ◽  
Operating Conditions ◽  
Flame Stability ◽  
Nox Emissions ◽  
Complete Combustion ◽  
Complete Control ◽  
Low Load ◽  
Combustion Technique

Abstract This review overviews combustion technologies for reduced emissions and better fuel economy in industrial gas turbine. Lean premixed combustion (LPM) technology is introduced as a low-temperature combustion technique to control NOx emissions. The Dry Low NOx (DLN) is one of the most promising LPM-based combustors for controlling NOx emissions. However, DLN combustors suffer from limited flame stability, especially under low load (near blowout) operating conditions, in addition to the difficulty of separating CO2 from the exhaust stream for reducing the gas-turbine carbon footprint. Trying to overcome such difficulties, the gas turbine manufacturers developed enhanced-design burners for higher turndown and lower NOx emissions, including the Dual Annular Counter Rotating Swirl (DACRS) and environmental-Vortex (EV) burners. The volume of the DACRS combustors is almost twice the conventional burners, which provide ample residence time for complete combustion. The mixing effectiveness is improved in EV-burners resulting in higher flame stability at low load or startup conditions. To widen the operability, control the emissions, and improve the turndown ratio of gas turbine combustors, the concept of flame stratification, i.e., heterogenization of the overall equivalence ratio, was introduced. This technique can widen the stability range of existing LPM flames for industrial applications. Integrating stratified combustion technique with oxy-fuel combustion technology is a way forward that may result in complete control of gas turbine emissions with higher operability turndown ratio. The recent developments and challenges towards the application of hydrogen gas turbine are introduced.

Cake Formation in Cross-Flow Microfiltration Systems

1992 ◽  
Vol 25 (10) ◽  
pp. 149-162 ◽  
Author(s):  
V. L. Pillay ◽  
C. A. Buckley
Keyword(s):  
Cross Flow ◽  
Operating Conditions ◽  
Waste Waters ◽  
Domestic Waste ◽  
Time Curve ◽  
Good Correspondence ◽  
Operating Variables ◽  
Start Up ◽  
Turbulent Flow Regime ◽  
Cake Formation

Cross-flow microfiltration (CFMF) has potentially wide application in the processing of industrial and domestic waste waters. Optimum design and operation of CFMF systems necessitates a knowledge of the characteristic system behaviour, and an understanding of the mechanisms governing this behaviour. This paper is a contribution towards the elucidation and understanding of the behaviour of a woven fibre CFMF operated in the turbulent flow regime. The characteristic flux-time curve and effects of operating variables on flux are presented for a limestone suspension cross-flow filtered in a 25 mm woven fibre tube. The phenomena contributing to the shape of the flux-time curve are discussed. A model of the mechanisms governing cake growth and limit is presented. Predicted steady-state fluxes show a notably good correspondence with experimentally measured values. It is also found that the flux may not be uniquely defined by the operating conditions, but may also be a function of the operating path taken to reach the operating point. This is of significance in the start-up and operation of CFMF units.

Study on the Flow Characteristics of Shengli Oilfield Super Heavy Oil

2017 ◽  
Vol 10 (1) ◽  
pp. 69-78 ◽  
Author(s):  
Wang Shou-long ◽  
Li Ai-fen ◽  
Peng Rui-gang ◽  
Yu Miao ◽  
Fu Shuai-shi
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Heavy Oil ◽  
Flow Characteristics ◽  
Fluid Viscosity ◽  
Linear Flow ◽  
Start Up ◽  
Non Linear ◽  
Core Permeability ◽  
Velocity Pressure

Objective:The rheological properties of oil severely affect the determination of percolation theory, development program, production technology and oil-gathering and transferring process, especially for super heavy oil reservoirs. This paper illustrated the basic seepage morphology of super heavy oil in micro pores based on its rheological characteristics.Methods:The non-linear flow law and start-up pressure gradient of super heavy oil under irreducible water saturation at different temperatures were performed with different permeable sand packs. Meanwhile, the empirical formulas between start-up pressure gradient, the parameters describing the velocity-pressure drop curve and the ratio of gas permeability of a core to fluid viscosity were established.Results:The results demonstrate that temperature and core permeability have significant effect on the non-linear flow characteristics of super heavy oil. The relationship between start-up pressure gradient of oil, the parameters representing the velocity-pressure drop curve and the ratio of core permeability to fluid viscosity could be described as a power function.Conclusion:Above all, the quantitative description of the seepage law of super heavy oil reservoir was proposed in this paper, and finally the empirical diagram for determining the minimum and maximum start-up pressure of heavy oil with different viscosity in different permeable formations was obtained.

scholarly journals Applications of Biocatalysts for Sustainable Oxidation of Phenolic Pollutants: A Review

2021 ◽  
Vol 13 (15) ◽  
pp. 8620
Author(s):  
Sanaz Salehi ◽  
Kourosh Abdollahi ◽  
Reza Panahi ◽  
Nejat Rahmanian ◽  
Mozaffar Shakeri ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Operating Conditions ◽  
Phenolic Pollutants ◽  
Petroleum Refinery Wastewater ◽  
Start Up ◽  
Low Concentrations ◽  
Effective Removal ◽  
Wide Range ◽  
Loading Effects ◽  
Spent Caustic

Phenol and its derivatives are hazardous, teratogenic and mutagenic, and have gained significant attention in recent years due to their high toxicity even at low concentrations. Phenolic compounds appear in petroleum refinery wastewater from several sources, such as the neutralized spent caustic waste streams, the tank water drain, the desalter effluent and the production unit. Therefore, effective treatments of such wastewaters are crucial. Conventional techniques used to treat these wastewaters pose several drawbacks, such as incomplete or low efficient removal of phenols. Recently, biocatalysts have attracted much attention for the sustainable and effective removal of toxic chemicals like phenols from wastewaters. The advantages of biocatalytic processes over the conventional treatment methods are their ability to operate over a wide range of operating conditions, low consumption of oxidants, simpler process control, and no delays or shock loading effects associated with the start-up/shutdown of the plant. Among different biocatalysts, oxidoreductases (i.e., tyrosinase, laccase and horseradish peroxidase) are known as green catalysts with massive potentialities to sustainably tackle phenolic contaminants of high concerns. Such enzymes mainly catalyze the o-hydroxylation of a broad spectrum of environmentally related contaminants into their corresponding o-diphenols. This review covers the latest advancement regarding the exploitation of these enzymes for sustainable oxidation of phenolic compounds in wastewater, and suggests a way forward.

scholarly journals A Model for Predicting Arsenic Volatilization during Coal Combustion Based on the Ash Fusion Temperature and Coal Characteristic

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Bo Zhao ◽  
Geng Chen ◽  
Zijiang Xiong ◽  
Linbo Qin ◽  
Wangsheng Chen ◽  
...  
Keyword(s):  
Coal Combustion ◽  
Power Plants ◽  
Combustion Temperature ◽  
Published Data ◽  
Fusion Temperature ◽  
Equilibrium Calculation ◽  
Arsenic Distribution ◽  
Ash Fusion Temperature ◽  
Close Relationship ◽  
Coal Type

Arsenic emission from coal combustion power plants has attracted increasing attention due to its high toxicity. In this study, it was found that there was a close relationship between the ash fusion temperature (AFT) and arsenic distribution based on the thermodynamic equilibrium calculation. In addition to the AFT, coal characteristics and combustion temperature also considerably affected the distribution and morphology of arsenic during coal combustion. Thus, an arsenic volatilization model based on the AFT, coal type, and combustion temperature during coal combustion was developed. To test the accuracy of the model, blending coal combustion experiments were carried out. The experimental results and published data proved that the developed arsenic volatilization model can accurately predict arsenic emission during co-combustion, and the errors of the predicted value for bituminous and lignite were 2.3–9.8%, with the exception of JingLong (JL) coal when combusted at 1500 °C.

Co-firing sludge in a pulverized coal-fired utility boiler: Combustion characteristics and economic impacts

Energy ◽  
2017 ◽  
Vol 119 ◽  
pp. 392-399 ◽  
Author(s):  
Peng Tan ◽  
Lun Ma ◽  
Ji Xia ◽  
Qingyan Fang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Economic Impacts ◽  
Combustion Characteristics ◽  
Pulverized Coal ◽  
Utility Boiler

Numerical Simulation on Improving NOx Reduction Efficiency of SNCR by Regulating the 3-D Temperature Field in a Furnace

2013 ◽  
Vol 807-809 ◽  
pp. 1505-1513 ◽  
Author(s):  
Amir A.B. Musa ◽  
Xiong Wei Zeng ◽  
Qing Yan Fang ◽  
Huai Chun Zhou
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Removal Efficiency ◽  
Pulverized Coal ◽  
Measuring System ◽  
Optimum Temperature ◽  
Utility Boiler ◽  
Coal Particles ◽  
Injection Zone ◽  
Reduction Efficiency

The optimum temperature within the reagent injection zone is between 900 and 1150°C for the NOX reduction by SNCR (selective non-catalytic reduction) in coal-fired utility boiler furnaces. As the load and the fuel property changes, the temperature within the reagent injection zone will bias from the optimum range, which will reduces significantly the de-NOX efficiency, and consequently the applicability of SNCR technology. An idea to improve the NOX reduction efficiency of SNCR by regulating the 3-D temperature field in a furnace is proposed in this paper. In order to study the new method, Computational fluid dynamics (CFD) model of a 200 MW multi-fuel tangentially fired boiler have been developed using Fluent 6.3.26 to investigate the three-fuel combustion system of coal, blast furnace gas (BFG), and coke oven gas (COG) with an eddy-dissipation model for simulating the gas-phase combustion, and to examine the NOX reduction by SNCR using urea-water solution. The current CFD models have been validated by the experimental data obtained from the boiler for case study. The results show that, with the improved coal and air feed method, average residence time of coal particles increases 0.3s, burnout degree of pulverized coal increases 2%, the average temperature at the furnace nose decreases 61K from 1496K to 1435K, the NO emission at the exit (without SNCR) decreases 58 ppm from 528 to 470 ppm, the SNCR NO removal efficiency increases 10% from 36.1 to 46.1%. The numerical simulation results show that this combustion adjustment method based on 3-D temperature field reconstruction measuring system in a 200 MW multi-fuel tangentially fired utility boiler co-firing pulverized coal with BFG and COG is timely and effective to maintain the temperature of reagent injection zone at optimum temperature range and high NOX removal efficiency of SNCR.

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