Combustion and Fouling Characteristics of Two Canadian Lignites

1972 ◽  
Vol 94 (2) ◽  
pp. 127-132 ◽  
Author(s):  
F. D. Friedrich ◽  
G. K. Lee ◽  
E. R. Mitchell
Keyword(s):  
Eutectic Composition ◽  
Pilot Scale ◽  
Flame Stability ◽  
Ash Deposition ◽  
James Bay ◽  
Selective Deposition ◽  
Complete Combustion ◽  
Ash Deposit ◽  
Combustion Tests ◽  
Fouling Characteristics

The report describes combustion tests with Bienfait lignite from Saskatchewan and Onakawana lignite from James Bay. They were burned in a pilot-scale, pulverized-fired boiler primarily to study combustion performance and fireside fouling tendencies under slag-tap conditions. Flame stability and complete combustion were readily obtained, although satisfactory slag tapping was not achieved with either fuel. Fireside ash deposit samples, representing each fuel, were collected from various parts of the boiler and subjected to exhaustive analyses. The results indicate that, when burning Bienfait lignite, selective deposition of ash constituents takes place, resulting in a eutectic composition downstream of the furnace exit. In the case of Onakawana lignite, selective ash deposition did not occur. Deposit analyses, fusion temperatures, and enrichment ratios are given for both fuels.

scholarly journals Fluidized bed combustion of pesticide-manufacture liquid wastes

2010 ◽  
Vol 75 (4) ◽  
pp. 523-535 ◽  
Author(s):  
Zorana Arsenijevic ◽  
Zeljko Grbavcic ◽  
Bosko Grbic ◽  
Nenad Radic ◽  
Radmila Garic-Grulovic ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Liquid Waste ◽  
Pilot Scale ◽  
Production Plant ◽  
Gaseous Emissions ◽  
Fluidized Bed Combustion ◽  
Complete Combustion ◽  
Liquid Wastes ◽  
Combustion Tests ◽  
Additional Fuel

Industrial liquid wastes can be in the form of solutions, suspensions, sludges, scums or waste oil and have organic properties. The objective of this work was to demonstrate the technical feasibility of a fluidized bed as a clean technology for burning liquid waste from a pesticide production plant. The combustion of liquid waste mixtures, obtained from realistic samples, was investigated in a pilot scale fluidized bed with quartz sand particles of 0.63-1.25 mm in diameter and 2610 kg/m3 in density at 800-950?C. To ensure complete combustion of liquid waste and additional fuel, the combustion chamber was supplied with excess air and the U/UmF (at ambient temperature) was in between 1.1 and 2.3. In the fluidized bed chamber, liquid waste, additional liquid fuel and air can be brought into intense contact sufficient to permit combustion in bed without backfire problems. The experimental results show that the fluidized bed furnace offers excellent thermal uniformity and temperature control. The results of the combustion tests showed that degradation of liquid wastes can be successfully realized in a fluidized bed with no harmful gaseous emissions by ensuring that the temperatures of both the bed and the freeboard are not lower than 900?C.

scholarly journals Investigation of Ash Deposition Dynamic Process in an Industrial Biomass CFB Boiler Burning High-Alkali and Low-Chlorine Fuel

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1092
Author(s):  
Hengli Zhang ◽  
Chunjiang Yu ◽  
Zhongyang Luo ◽  
Yu’an Li
Keyword(s):  
Gas Flow ◽  
Circulating Fluidized Bed ◽  
Deposition Process ◽  
Biomass Combustion ◽  
Ash Deposition ◽  
Biomass Ash ◽  
Cfb Boiler ◽  
Third Stage ◽  
Ash Deposit ◽  
High Alkali

The circulating fluidized bed (CFB) boiler is a mainstream technology of biomass combustion generation in China. The high flue gas flow rate and relatively low combustion temperature of CFB make the deposition process different from that of a grate furnace. The dynamic deposition process of biomass ash needs further research, especially in industrial CFB boilers. In this study, a temperature-controlled ash deposit probe was used to sample the deposits in a 12 MW CFB boiler. Through the analysis of multiple deposit samples with different deposition times, the changes in micromorphology and chemical composition of the deposits in each deposition stage can be observed more distinctively. The initial deposits mainly consist of particles smaller than 2 μm, caused by thermophoretic deposition. The second stage is the condensation of alkali metal. Different from the condensation of KCl reported by most previous literatures, KOH is found in deposits in place of KCl. Then, it reacts with SO2, O2 and H2O to form K2SO4. In the third stage, the higher outer layer temperature of deposits reduces the condensation rate of KOH significantly. Meanwhile, the rougher surface of deposits allowed more calcium salts in fly ash to deposit through inertial impact. Thus, the elemental composition of deposits surface shows an overall trend of K decreasing and Ca increasing.

Potential of Industrial Solid Wastes as an Energy Source and Gaseous Emissions Evaluation in a Pilot Scale Burner

2008 ◽  
Author(s):  
Silvia L. Floriani ◽  
Elaine Virmond ◽  
Christine Albrecht Althoff ◽  
Regina F. P. M. Moreira ◽  
Humberto J. Jose´
Keyword(s):  
Energy Source ◽  
Alternative Energy ◽  
Chemical Properties ◽  
Pilot Scale ◽  
Volatile Matter ◽  
Industrial Wastes ◽  
Gaseous Emissions ◽  
Gas Treatment ◽  
Combustion Tests ◽  
Lower Heating

Biomass is currently used as an alternative energy source in some industries. Due to problems with disposal of wastes, using biomass as an energy source is economically and environmentally attractive. In this work seven wastes from textile and food industry were characterized and their gaseous emissions resulting from their combustion in a pilot unit were measured. The aim of this paper is to evaluate the usage of industrial wastes as an energy source taking into account their composition and gaseous emissions when submitted to combustion tests. Gaseous emissions were compared to limits imposed by Brazilian and international current legislations. Volatile organic compounds (VOC) were analyzed by GC-MS and their content values were expressed as total organic carbon (TOC). Four combustion tests were carried out in a cyclone combustor and all TOC emissions were below regulations limits. CO, CO2, NOx, CxHy and SO2 were also measured. Chemical properties showed that the volatile matter values of all biomass were high what indicate that the solids burn rapidly and some biomass presented high levels of sulphur and consequently high levels of emission of SO2 when burned. The lower heating values ranged from 14.22 to 22.93 MJ.kg−1. Moisture content and particulate matter (PM) were measured during the combustion tests and showed effective combustion conditions. Thermogravimetric analysis of the biomasses showed ignition temperatures and maximum burning rate which were compared to other papers data. The usage of these biomasses as an energy source is possible however gas treatment would be required specially if the solid presents high levels of sulphur and chlorine.

Fouling of Heat Exchanger Tubes in Pulverized-Coal-Fired Combustion Chambers

2008 ◽  
Author(s):  
Efim Korytni ◽  
Yuli Berman ◽  
Boris Davidson ◽  
Miron Perelman ◽  
Roman Saveliev ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Power Plants ◽  
Ash Deposition ◽  
Axially Symmetric ◽  
Combustion Chambers ◽  
Weakly Bound ◽  
Water Steam ◽  
Overall Heat Transfer Coefficient ◽  
Utility Boilers ◽  
Ash Deposit

Fouling is a major concern in coal-fired power plants caused by fly ash deposit on the heat exchanger tubes that decreases the overall heat transfer coefficient to water-steam mixture. Fouling has been characterized by weakly bound-loose form, which may be removed by various methods, such as soot-blowing, blast, and sand blowing. We have carried out experimental and modeling work on fouling to develop a methodology by which the thermal conductivity of the ash deposit would be determined in a way similar to the fouling process prevailing in real systems. For that we used tubes identical in material, diameter and temperature to those used in many utility boilers. In the experimental work we placed a tube in an axially symmetric 50 kW furnace, and tested fouling from three coals, bituminous and sub-bituminous. We also developed a dynamic model for the prediction of the ash deposition growth and its heat resistance. Comparison of the model prediction and experimental results yielded satisfactory fit. Consequently, thermal resistance of heat exchanger tuber with ash deposit of those coals was determined.

Development of Low Emission Gas Turbine Combustors

2015 ◽  
Author(s):  
Seung-chai Jung ◽  
Siwon Yang ◽  
Shaun Kim ◽  
Ik Soo Kim ◽  
Chul-ju Ahn ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Flow Characteristics ◽  
Flame Stability ◽  
Fuel Distribution ◽  
Eddy Simulation ◽  
Piv Measurement ◽  
Planar Laser ◽  
Air Mixing ◽  
Industrial Gas Turbines ◽  
Combustion Tests

Due to increasing environmental concerns, clean technology has become a key feature in industrial gas turbines. Swirler design is directly associated with the combustion performance for its roles in fuel distribution and flame stability. In this study, the development process of three new conceptual swirlers from Samsung Techwin is presented. Each swirler has unique features to enhance fuel-to-air mixing; Swirler 1 uses tangential air-bypass, Swirler 2 minimizes pressure loss using impeller-like design, and Swirler 3 has combined flow characteristics of axial and radial swirlers. Using extensive computational fluid dynamics (CFD) analysis, lead time and cost in manufacturing the prototypes were significantly reduced. The numerical methods were verified with a lab-scale combustion test; particle image velocimetry (PIV) measurement of cold flow, direct flame images, and OH planar laser induced fluorescence (PLIF) images were compared with result of large-eddy simulation (LES), and they showed good agreement. After design optimization using CFD, full-scale combustion tests were performed for all three swirlers. Flame from each swirler was visualized using a cylindrical quartz liner; direct images and OH chemiluminescence images of flames were obtained. Flame stability and blow-off limit at various air load were examined by gradually lowering the equivalence ratio. NOx and CO concentration were measured at the exhaust. All three swirlers satisfied low NOx and CO levels at the design conditions. The performance maps bounded by the NOx and CO limits and blow-off limit were obtained for all swirlers. Further efforts to maximize the combustors performance will be made.

scholarly journals Characteristics of Flame Stability and Gaseous Emission of Bio-Crude Oil from Coffee Ground in a Pilot-Scale Spray Burner

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2882
Author(s):  
Sang Kyu Choi ◽  
Yeon Seok Choi ◽  
Yeon Woo Jeong ◽  
So Young Han ◽  
Quynh Van Nguyen
Keyword(s):  
Crude Oil ◽  
Pilot Scale ◽  
High Viscosity ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Injection System ◽  
Optimum Operating ◽  
Flame Stability ◽  
Gaseous Emission ◽  
Coffee Ground

Coffee ground has been recently considered as a new biomass resource in relation to the increasing coffee consumption worldwide. The bio-crude oil can be produced by fast pyrolysis of coffee ground, and it has advantages of larger heating values in comparison with those from other biomass. But the bio-crude oil from coffee ground has a significantly high viscosity which can hinder the application to conventional burners. In this study, a pilot-scale burner system with a 35 kW capacity with an air-blast atomizing nozzle was developed for the combustion of bio-crude oil from coffee ground with a high viscosity. A downward fuel injection system was adopted to enhance the ignition of fuel spray and the flame stabilization, and a movable block swirl generator was installed for the combustion air. The bio-crude oil was blended with ethanol at the volumetric ratio of 9:1 to enhance the combustion characteristics. The effect of various atomizing air pressures, swirl intensities, and overall equivalence ratios on the flame stability and gaseous emission were investigated to find out the optimum operating conditions for a bio-crude oil burner.

Ash Deposit Shedding during Co-combustion of Coal and Rice Hull Using a Digital Image Technique in a Pilot-Scale Furnace

2013 ◽  
Vol 27 (11) ◽  
pp. 7126-7137 ◽  
Author(s):  
Hao Zhou ◽  
Hailong Zhang ◽  
Letian Li ◽  
Bin Zhou
Keyword(s):  
Digital Image ◽  
Pilot Scale ◽  
Rice Hull ◽  
Image Technique ◽  
Ash Deposit
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