Some special features of combusting the coal-water fuel made of Belarussian brown coals in the fluidized bed

Borodulya, V. A.; Buchilko, É. K.; Vinogradov, L. M.

doi:10.1134/s0040601514040016

Cited by 14 publications

(4 citation statements)

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“…The experiments have shown that the ignition stages of CWSP correspond well to modern ideas about the ignition of CWS, regardless of the component composition of CWSP. − ,− In particular, we observed the following processes during the experiments: (i) inert heating of the fuel droplet, (ii) evaporation of liquid components (oil and water) from the near-surface layer, (iii) thermal decomposition of the organic portion of coal in the near-surface layer of the particle, (iv) mixing of the products of thermal decomposition and evaporation with the oxidant, (v) combustion initiation of the emerging gas mixture, (vi) heating of the coke residue, (vii) heterogeneous ignition of the coke residue, and (viii) combustion of the coke residue. These stages are the same for various types of coal components and liquid combustible components.…”

Section: Resultssupporting

confidence: 78%

Ignition of the Coal–Water Slurry Containing Petrochemicals and Charcoal

2016

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The lack of effective technologies to use coal processing waste and waste flammable liquids is a major research and development problem. To address this problem, we study the ignition characteristics and conditions for coal–water slurries (CWS) based on these wastes. The key challenge posed by the wastes under study is their poor reactivity (they require more power resources for sustainable ignition). Therefore, this paper suggests adding a highly reactive material (charcoal) in a low concentration to coal–water-slurry containing petrochemicals (CWSP) based on wastes. Individual CWSP droplets are studied in a model combustion chamber. The integral characteristics of the processes under study (ignition delay time and minimum oxidizer temperatures sufficient for ignition) are determined for a CWSP droplet of 0.5–2 mm in radius fixed at the junction of a low-inertia thermocouple using a high-speed (up to 105 fps) video camera and Tema Automotive software. We compare the ignition characteristics of CWSP compositions based on charcoal and brown coal as well as filter cakes (processing waste) of coking, low-caking, and non-baking coals in an oxidizer flow (temperature of 600–1000 K and velocity of 0.5–5 m/s). Charcoal is a promising additional component for the CWS and CWSP. In view of ecological, economic, and energy-related aspects, it is advisible to use charcoal as an additive to intensify the CWS and CWSP ignition. Even a small addition (within 10–15% in relative mass concentration) of this component may significantly reduce the limit (minimum) temperature of sustainable ignition and ignition delay time (inertia).

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Section: Resultssupporting

confidence: 78%

Ignition of the Coal–Water Slurry Containing Petrochemicals and Charcoal

2016

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“…Coal concentration in a CWS can vary in the range of 40–60%. − In high concentrated CWS, the mass fraction of coal can reach 70–72%. , The range of mass concentrations of liquid combustible components in a slurry fuel can vary from very low values (for instance, in ref , mass concentration of waste motor oil used as a stabilizing agent was 0.3%) to higher values. For coal–oil suspensions, the mass concentration of organic liquid (for instance, mazut, heavy crude oil, kerosene) varies in the range of 46–70%. − Therefore, the results obtained in the given research (dependences for τ d , τ c , T d max , and T g min ) are of particular interest for water–coal technologies with high content of solid fuel in suspensions.…”

Section: Resultsmentioning

confidence: 85%

“…In addition to the problem of recycling the waste of processing coal and oil, large-scale involvement of CWS and CWSP in the power industry will reduce a number of power plants operating with coal. In turn, this will reduce the dangerous environmental impact. − References and reported that combustion of CWS greatly reduces the emissions of NO x and SO x to the environment in comparison to conventional pulverized coal. There are prospects for reducing CO 2 emissions by converting solid fuels into CWSP.…”

Section: Introductionmentioning

confidence: 99%

Ignition Characteristics of Coal–Water Slurry Containing Petrochemicals Based on Coal of Varying Degrees of Metamorphism

2016

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This paper examines a coal–water slurry containing petrochemicals (CWSP) based on lignite, bituminous coal, anthracite, and typical wastecarbon residue obtained from the pyrolysis of tires. Waste motor oil is used as a liquid fuel component of the slurry. The study of CWSP ignition is performed via placing a fuel droplet on a low-inertia thermocouple junction (junction diameter is 0.1 mm; thermal inertia is less than 1 s) into the hot oxidant flow. The temperature and velocity of the oxidant flow vary in the range of 600–1200 K and 0.5–5 m/s, respectively. These ranges are typical for power plants in the large- and small-scale energy industry. The paper specifies the minimum oxidant temperatures which are sufficient for sustainable ignition, as well as the ignition delay times, the times for complete burnout of CWSP droplets (radii of 0.5–2 mm), and the maximum temperatures in the fuel combustion area. We discuss how the oxidant temperature and the component composition of CWSP influence the parameters listed above. Addition of a small amount of coal (with high content of volatiles) in a fuel composition can decrease the ignition temperature of CWSP based on bituminous coal and even anthracite by 50–150 K compared to that which is a traditional one for the energy sector. At the same time, the presence of coal of a high degree of metamorphism in CWSP leads to a substantial increase in the temperature in the fuel combustion zone, as well as in the duration of this process (as a result, more heat is released). The paper indicates the compositions which are characterized by minimum ignition lag, low temperature of ignition, and relatively high temperatures of combustion.

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“…At the end of XX century the basic data about combustion of the WCF were obtained and at the same time the effective technologies of preparation and usage of water-coal slurries were created [17][18][19][20][21][22][23][24][25][26]. However, taking in account the real needs in usage of WCF, some countries with deficit of natural resources support research and development activities for improvement of water-coal technologies [2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

The Review of Ignition and Combustion Processes for Water-Coal Fuels

Iegorov

Стрижак

Chernetskiy

2016

EPJ Web of Conferences

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Abstract. In this work we have reviewed the most of known investigations of the initialization of combustion processes of water-coal fuels. The main problems of such study were emphasized. The definitive effects and factors (like mixing ratio, milling quality, the temperature of the oxidant, properties of the components and methods of the slurry preparation etc.) which have strong influence on inertia and stability of the ignition were analyzed.

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Some special features of combusting the coal-water fuel made of Belarussian brown coals in the fluidized bed

Cited by 14 publications

References 0 publications

Ignition of the Coal–Water Slurry Containing Petrochemicals and Charcoal

Ignition of the Coal–Water Slurry Containing Petrochemicals and Charcoal

Ignition Characteristics of Coal–Water Slurry Containing Petrochemicals Based on Coal of Varying Degrees of Metamorphism

The Review of Ignition and Combustion Processes for Water-Coal Fuels

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