Laser-Induced Emission of Ultrafine Particulates Evolved by Pulverized Coal Pyrolysis

2011 ◽  
Author(s):  
Linghong Chen ◽  
Zhenyan Pan ◽  
Kefa Cen ◽  
Kunzan Qiu ◽  
Gerard Grehan
Keyword(s):  
High Temperature ◽  
Time Constant ◽  
Ultrafine Particles ◽  
Pulverized Coal ◽  
Coal Pyrolysis ◽  
Heated Particle ◽  
Coal Particles ◽  
Hydrogen Flame ◽  
Laser Heated ◽  
Peak Value

The importance of on line measurement of ultrafine particulates in pulverized coal flames is mainly due to the detection of ultrafine particulate in the effluent for pollution control, and the quantification of fuel burnout in real time within a boiler for improved understanding of the flame heat transfer soot modeling as well. A method has been investigated using laser-heated emission within an O2-free flame which provides a continuous in situ measurement of ultrafine particles during high-temperature pulverized coal pyrolysis. Bituminous coal particles are entrained by nitrogen along the centerline of a laminar flow flat flame burner, where a hydrogen-air flame under fuel-rich condition is used as a heat source. The temperatures of the hydrogen flame were measured by a finite-wire silica-coated Platinum-Rhodium type B Thermocouple. Volatiles released during the coal pyrolysis form a cloud of ultrafine particles at high temperature. A pulse laser sheet introduced to the flame heats the ultrafine particles to incandescent temperatures. The time-resolved laser-induced emission signals with different incident laser-pulse fluences were evaluated. The volume faction of ultrafine particles was associated with the peak value of the signals, and the mean particle size characterized by a time constant of the exponential signal decay. A strong dependence of the characteristic peak value and emission time constant during laser-heated particle cooling from the measured coal particle class could be determined. Specialties in signal evaluation due to residence time in the hydrogen flame for two sizes of coal particles are discussed.

Combustion rates of pulverized coal particles in high-temperature/high-oxygen concentration atmosphere

1991 ◽  
Vol 87 (1) ◽  
pp. 1-12 ◽  
Author(s):  
M. Saito ◽  
M. Sadakata ◽  
M. Sato ◽  
T. Soutome ◽  
H. Murata ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Concentration ◽  
Pulverized Coal ◽  
High Oxygen ◽  
High Oxygen Concentration ◽  
Coal Particles

Experimental Study on Carbonization of Low-Rank Pulverized Coal with High Temperature Heat Pipe

2014 ◽  
Vol 953-954 ◽  
pp. 1035-1039
Author(s):  
Li Qun Wang ◽  
Zhong Bo Yi ◽  
Zhong Xiang Wei
Keyword(s):  
High Temperature ◽  
Heat Pipe ◽  
Pulverized Coal ◽  
Holding Time ◽  
Raw Material ◽  
Low Rank ◽  
Experimental Result ◽  
Operating Characteristics ◽  
Temperature Heat ◽  
High Temperature Heat Pipe

Aimed at improving the utilization of pulverized coal, high-temperature heat pipe technology was introduced into lignite carbonization.Under the design of power of 10kw semi-industrial pulverized coal carbonization test equipment, Fugu lignite coal as raw material to investigate the operating characteristics of the device and carbonization characteristics. Experimental result shows that the high temperature heat pipes heat steadily and meet the temperature requirement of low-temperature carbonization. With the extension of the holding time, the semi-coke fixed carbon content increasing, but volatile matter vice versa, however, holding time above 60 minutes, the effect of carbonization is not obvious, and the best carbonization time is 30 ~ 60 minutes. The length of the holding time has little effect on gas composition, the content of H2 and CH4 are relatively higher than the rest gas, (H2 + CH4) gas accounted for 70% of the total, the heating value remains at 18.76 ~ 19.22MJ/m3, belongs to medium-high value gas, could provide for industrial and civilian use.

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.

Comparison of Sieve Diameter and Stokes' Diameter Distributions for Pulverized Coal Particles

1981 ◽  
Vol 27 (1-2) ◽  
pp. 79-82 ◽  
Author(s):  
L. M. COHEN ◽  
M. R. DENISON ◽  
N. GAT ◽  
A. B. WITTE
Keyword(s):  
Pulverized Coal ◽  
Coal Particles ◽  
Diameter Distributions

346. Measurements of the rate of change of temperature in high temperature-short time pasteurization plant

1947 ◽  
Vol 15 (1-2) ◽  
pp. 18-23
Author(s):  
F. Steghart
Keyword(s):  
High Temperature ◽  
Time Constant ◽  
Rate Of Change ◽  
Hot Water ◽  
Water Pipe ◽  
Temperature Changes ◽  
Rates Of Change ◽  
High Temperature Short Time ◽  
Short Time

It has recently been claimed that in modern high temperature-short time pasteurization plant fluctuations in temperature of the order of 1° F./sec. are unusual and probably artefacts, and that an instantaneous drop is certainly fictitious.It has, nevertheless, been shown that such rapid drops in temperature do in fact occur frequently in high temperature-short time plants of the type investigated. The plant investigated was not of the latest design incorporating devices for speeding up the control by injecting steam directly into the hot-water pipe.Temperature changes of the order of those in question were first observed by Mattick & Hiscox(1) of the National Institute for Research in Dairying, who carried out tests on pasteurization plant using a small mirror galvanometer with a very short time constant. The maximum rates of change were, however, not observed.

Experimental study on electrostatic removal of high-carbon particle in high temperature coal pyrolysis gas

2019 ◽  
Vol 37 (3) ◽  
pp. 2959-2965 ◽  
Author(s):  
Chenghang Zheng ◽  
Xintao Liu ◽  
Xi Xu ◽  
Pei Yan ◽  
Qianyun Chang ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Carbon Particle ◽  
Coal Pyrolysis ◽  
High Carbon ◽  
Pyrolysis Gas
Sign in / Sign up

Export Citation Format

Share Document