The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform

F. Ohene - One of the best experts on this subject based on the ideXlab platform.

Pavel A. Strizhak - One of the best experts on this subject based on the ideXlab platform.

  • energy efficiency and environmental aspects of the combustion of coal water slurries with and without petrochemicals
    Journal of Cleaner Production, 2018
    Co-Authors: G. S. Nyashina, G V Kuznetsov, Pavel A. Strizhak
    Abstract:

    Abstract The paper presents the results of the experimental research into maximum concentrations of anthropogenic emissions from typical brown low-rank coal combustion in the traditional pulverized state as well as from the combustion of coal-water slurries with or without petrochemicals. The temperature of fuel heating in the model combustion chamber varied in the range from 500 °C to 1000 °C. The relative values of concentrations of anthropogenic emissions are calculated with due consideration of key energy characteristics of the fuel: combustion heat, specific mass of the fuel component in a mixture, specific energy obtained per fuel cost. The findings illustrate considerable differences not only between the concentrations of the analyzed anthropogenic emissions, but also between the times, during which these concentrations remained high. In addition, we compare the boundary conditions (i.e. borderline or minimum sustainable ignition temperatures) necessary and sufficient for the combustion of the fuel compositions under study and analyze fuel heating and ignition delay times. Special aspects are determined of the environmentally friendly combustion of coals as part of coal-water slurries with or without petrochemicals at different temperatures: from minimum temperatures usually observed at the beginning of sustainable ignition to those typical of small- or medium-sized power plants. Concentrations of the most hazardous oxides of sulfur and nitrogen produced during coal combustion are 3–5 times higher than during coal-water slurry combustion. The differences between these parameters for coals and coal-water slurries containing petrochemicals are less noticeable. Nevertheless, the emissions of nitrogen and sulfur oxides from the combustion of coal-water slurries containing petrochemicals are at least 30–60% lower than from the combustion of coals. Taking into account the cost of the components of coal-water slurries containing petrochemicals, as well as the combustion heat and the concentrations of anthropogenic emissions, specific indicators show that coal-water slurries containing petrochemicals are more efficient than coals or the coal-water slurries without petrochemicals. If filter cakes are used as the main component of coal-water slurries containing petrochemicals, the specific indicators of such fuels grow 5–6 times higher (or even 10 times higher in special cases) versus pure coals. The research findings show that the temperature monitoring in the combustion chamber is obligatory to provide high ecological indicators. At temperatures below 1000 °C, it is possible to provide stable combustion of fuels and significantly reduce emissions as compared to the traditional high-temperature regimes (above 1000 °C). Thus, temperatures lower than 1000 °C are more rational. Finally, the conditions for the optimal coal fuel combustion are presented in terms of the environmental friendliness, energy and cost efficiency, as well as fire and explosion safety.

  • Computational modeling of the combustion of coal water slurries containing petrochemicals
    Fuel, 2018
    Co-Authors: Mikhail Chernetskiy, Ksenia Vershinina, Pavel A. Strizhak
    Abstract:

    Abstract The combustion predictive model was developed based on the results of experiments with coal water slurry and coal water slurry containing petrochemicals. Unlike other known models, it takes into account the effect of liquid flammable component (in particular, engine oil waste) on the main mass and heat transfer as well as other physical and chemical processes in the combustion chamber. The main differences, conditions and characteristics of the combustion of coal water slurries containing petrochemicals and without additives have been studied theoretically with different defining parameters: fuel composition, component properties, and furnace chamber temperature. Temperature fields and volumetric concentration distribution of combustion products in the furnace chamber are established for fuel compositions based on water, coal, and industrial oil waste. Temperatures and concentrations for both the initial fuel components and their combustion products are established at different points of the furnace chamber for various component concentrations, properties, and furnace air temperatures. The main research findings are the quantitative differences between the characteristics of ignition and combustion of slurries with and without a liquid fuel component. These differences are critical to illustrate the benefits of using coal water slurries containing petrochemicals in heat and power plants. Adding as little as 10% (relative mass fraction) of waste industrial oils was shown to significantly reduce the ignition delay times and improve the combustion efficiency of fuel compositions. Possible ranges, in which the ignition delay of slurry fuels can be reduced, and the displacement of their ignition zones in the combustion chamber were determined when changing the temperature and the main fuel component – coal (as illustrated by brown and bituminous coals, as well as anthracite).

  • Ignition of composite liquid fuel droplets based on coal and oil processing waste by heated air flow
    Journal of Cleaner Production, 2017
    Co-Authors: Dmitrii O. Glushkov, Pavel A. Strizhak
    Abstract:

    To expand the resource base of fuels and methods of hydrocarbon waste recovery, this paper presents the study of the ignition features and conditions of composite fuel slurries based on wastes from coal, chemical, petrochemical, energy, and transport industries. Composite liquid fuels have been prepared using basic components: filter cakes of low-caking, nonbaking, and bituminous coal; engine, turbine, and transformer oil waste; plasticizer. According to a well-known experimental approach, the investigations of the ignition processes have been performed for single fuel droplets (with a radius ranging from 0.5 mm to 1.5 mm) covering a fast-response thermocouple junction. A heated air flow – the ignition source of a droplet – was formed by a specialized blower and a heater. The air temperature varied within the range of 600–900 K. The oxidizer flow velocity was about 3 m/s. With the help of particle image velocimetry hardware and Actual Flow software, we determined the conditions and characteristics of the oxidizer flow transformation around droplets of various shapes. The typical stages of fuel droplet ignition were identified using high-speed video cameras and Tema Automotive software: heating; the evaporation of water and flammable liquid; the thermal decomposition of coal; the formation and ignition of a gas-vapor mixture; the heating of coke residue; the heterogeneous ignition and combustion of carbon. Further, ignition delay times were determined under the conditions of low temperature (600–900 K) heating, as well as the combustion times of fuel droplets with different compositions. Finally, the minimum temperatures were specified sufficient for the sustainable ignition of composite liquid fuel. The established ranges of minimum temperatures show the possibility of burning fuel slurries based on coal and oil processing wastes in heat and power boilers of different capacity. The temperature modes can be adjusted to the required environmental, economic and energy performance indicators. The maximum temperature of a droplet during the combustion process is more than 1100 K. This result confirms the high combustion heat of fuel slurries, even those based on typical industrial wastes, and shows great prospects of their application in the thermal power engineering. The wide use of abundant industrial wastes as the main fuel components of coal water slurries containing petrochemicals is a high-potential solution to the global problem of their recovery and the reduction of the environmental load of coal-based thermal power engineering on the nature and humankind.

  • differences in the ignition characteristics of coal water slurries and composite liquid fuel
    Solid Fuel Chemistry, 2016
    Co-Authors: Yu K Vershinina, D. O. Glushkov, G V Kuznetsov, Pavel A. Strizhak
    Abstract:

    The processes of the inert heating, ignition, and combustion of the drops of typical coal–water slurries and promising composite liquid fuel were experimentally studied with the use of high-speed (to 105 frame/s) video recording facilities. The particles of brown and black coals with of sizes 80–100 μm were used as the basic components of the coal–water slurries and composite liquid fuel. Spent automobile oil (from an internal combustion engine) was also added to the composite liquid fuel (relative mass concentration, 0–15%). The characteristic stages of the processes of the inert heating and evaporating of liquid components and the ignition and combustion of coal–water slurries and composite liquid fuel (the initial radii of drops varied from 0.5 to 2 mm) were established. The ignition delay and complete combustion times of the drops of fuel compositions were determined under changes of the temperature of an oxidizing agent (air) in a range from 600 to 900 K at fluid velocities from 0.5 to 5 m/s. Representative temperatures at the centers of coal–water slurry and composite liquid fuel drops were measured at all of the established stages of the combustion initiation process. The necessary and sufficient conditions for the steady ignition of the drops of the test fuel compositions were recognized.

  • Differences in the ignition characteristics of coal–water slurries and composite liquid fuel
    Solid Fuel Chemistry, 2016
    Co-Authors: K. Yu. Vershinina, G V Kuznetsov, D. O. Glushkov, Pavel A. Strizhak
    Abstract:

    The processes of the inert heating, ignition, and combustion of the drops of typical coal–water slurries and promising composite liquid fuel were experimentally studied with the use of high-speed (to 10^5 frame/s) video recording facilities. The particles of brown and black coals with of sizes 80–100 μm were used as the basic components of the coal–water slurries and composite liquid fuel. Spent automobile oil (from an internal combustion engine) was also added to the composite liquid fuel (relative mass concentration, 0–15%). The characteristic stages of the processes of the inert heating and evaporating of liquid components and the ignition and combustion of coal–water slurries and composite liquid fuel (the initial radii of drops varied from 0.5 to 2 mm) were established. The ignition delay and complete combustion times of the drops of fuel compositions were determined under changes of the temperature of an oxidizing agent (air) in a range from 600 to 900 K at fluid velocities from 0.5 to 5 m/s. Representative temperatures at the centers of coal–water slurry and composite liquid fuel drops were measured at all of the established stages of the combustion initiation process. The necessary and sufficient conditions for the steady ignition of the drops of the test fuel compositions were recognized.

G Atesok - One of the best experts on this subject based on the ideXlab platform.

  • the effect of carboxymethyl cellulose cmc on the stability of coal water slurries
    Fuel, 2005
    Co-Authors: Feridun Boylu, G Atesok, H Dincer
    Abstract:

    In this study, the effect of carboxymethyl cellulose (CMC) used as stabilizer in the preparation of coal-water slurries on the stability has been investigated. Experiments have been carried out on the coal samples which differ in rank. Besides two different Turkish Lignites (Soma and Istanbul) also a bituminous coal (Thermal Code No. 434) of Turkish origin (Zonguldak) with medium volatile matter has been used. The results of the experiments showed that polymeric anionic CMC agent has much greater effect on the stability of CWS prepared from bituminous coal. Also, we found that inorganic mineral matters were able to be used as a stabilizer for preventing the sedimentation and separation of CWS.

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • the effect of chemicals on the viscosity and stability of coal water slurries
    International Journal of Mineral Processing, 2003
    Co-Authors: H Dincer, Feridun Boylu, Ayhan Ali Sirkeci, G Atesok
    Abstract:

    Abstract In this study, the effects of different chemicals that were used as dispersing agent and stabiliser on the stability and viscosity of coal–water slurries have been investigated. In the experiments, anionic type of chemicals—polyisoprene sulphonic acid soda (Dynaflow-K), a derivative of carboxylic acid (AC 1320) and naphthalenesulfonate–formaldehyde condensate (NSF)—were used as dispersing agents and the stabiliser was the sodium salt of carboxymethyl cellulose (CMC-Na). The coal sample used was a bituminous coal (thermal code no. 434) of Turkish origin, with medium volatile matter. The results of the experiments showed that polymeric anionic dispersing agents such as Dynaflow have much greater effect on the viscosity and the stability of coal water slurry.

  • the effect of coal properties on the viscosity of coal water slurries
    Fuel, 2002
    Co-Authors: G Atesok, Feridun Boylu, Ayhan Ali Sirkeci, H Dincer
    Abstract:

    Abstract Studies on coal–water slurries (CWSs) have been conducted for many years to replace fuel oil. In this research project, the effect of coal properties on CWSs have been investigated using two Turkish coals of different ranks and a Siberian bituminous coal. Physical, chemical and surface properties of coal samples were determined. Furthermore, adsorption tests were carried out in order to put forward the effect of additive adsorption on the viscosity of CWSs. Viscosity measurements were realized for CWSs of various solid ratios by weight that were prepared using coal samples having mean particle sizes of 19, 35 and 50 μm.

Feridun Boylu - One of the best experts on this subject based on the ideXlab platform.

  • the effect of carboxymethyl cellulose cmc on the stability of coal water slurries
    Fuel, 2005
    Co-Authors: Feridun Boylu, G Atesok, H Dincer
    Abstract:

    In this study, the effect of carboxymethyl cellulose (CMC) used as stabilizer in the preparation of coal-water slurries on the stability has been investigated. Experiments have been carried out on the coal samples which differ in rank. Besides two different Turkish Lignites (Soma and Istanbul) also a bituminous coal (Thermal Code No. 434) of Turkish origin (Zonguldak) with medium volatile matter has been used. The results of the experiments showed that polymeric anionic CMC agent has much greater effect on the stability of CWS prepared from bituminous coal. Also, we found that inorganic mineral matters were able to be used as a stabilizer for preventing the sedimentation and separation of CWS.

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • the effect of chemicals on the viscosity and stability of coal water slurries
    International Journal of Mineral Processing, 2003
    Co-Authors: H Dincer, Feridun Boylu, Ayhan Ali Sirkeci, G Atesok
    Abstract:

    Abstract In this study, the effects of different chemicals that were used as dispersing agent and stabiliser on the stability and viscosity of coal–water slurries have been investigated. In the experiments, anionic type of chemicals—polyisoprene sulphonic acid soda (Dynaflow-K), a derivative of carboxylic acid (AC 1320) and naphthalenesulfonate–formaldehyde condensate (NSF)—were used as dispersing agents and the stabiliser was the sodium salt of carboxymethyl cellulose (CMC-Na). The coal sample used was a bituminous coal (thermal code no. 434) of Turkish origin, with medium volatile matter. The results of the experiments showed that polymeric anionic dispersing agents such as Dynaflow have much greater effect on the viscosity and the stability of coal water slurry.

  • the effect of coal properties on the viscosity of coal water slurries
    Fuel, 2002
    Co-Authors: G Atesok, Feridun Boylu, Ayhan Ali Sirkeci, H Dincer
    Abstract:

    Abstract Studies on coal–water slurries (CWSs) have been conducted for many years to replace fuel oil. In this research project, the effect of coal properties on CWSs have been investigated using two Turkish coals of different ranks and a Siberian bituminous coal. Physical, chemical and surface properties of coal samples were determined. Furthermore, adsorption tests were carried out in order to put forward the effect of additive adsorption on the viscosity of CWSs. Viscosity measurements were realized for CWSs of various solid ratios by weight that were prepared using coal samples having mean particle sizes of 19, 35 and 50 μm.

H Dincer - One of the best experts on this subject based on the ideXlab platform.

  • the effect of carboxymethyl cellulose cmc on the stability of coal water slurries
    Fuel, 2005
    Co-Authors: Feridun Boylu, G Atesok, H Dincer
    Abstract:

    In this study, the effect of carboxymethyl cellulose (CMC) used as stabilizer in the preparation of coal-water slurries on the stability has been investigated. Experiments have been carried out on the coal samples which differ in rank. Besides two different Turkish Lignites (Soma and Istanbul) also a bituminous coal (Thermal Code No. 434) of Turkish origin (Zonguldak) with medium volatile matter has been used. The results of the experiments showed that polymeric anionic CMC agent has much greater effect on the stability of CWS prepared from bituminous coal. Also, we found that inorganic mineral matters were able to be used as a stabilizer for preventing the sedimentation and separation of CWS.

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • effect of coal particle size distribution volume fraction and rank on the rheology of coal water slurries
    Fuel Processing Technology, 2004
    Co-Authors: Feridun Boylu, H Dincer, G Atesok
    Abstract:

    AbstractThe aim of this study was to understanding of the effect of coal particle size distributions onrheology of coal–water slurries (CWS). Experiments have been carried out on the coal samples thatwere different in rank. Besides two different Turkish lignites (Soma and Istanbul–Agacli), abituminous coal from Siberia (Russia) has been used. In addition to the determination of thechemical and physical properties of the coal samples, their zeta potentials were also measured. Thepulps of different solids percentage composed of coal particles with d 50 sizes of 19, 35 and 50 Amwere used to determine the effect of volume fraction on the viscosity of the slurry.D 2003 Elsevier B.V. All rights reserved. Keywords: Coal; Coal–water slurries; Viscosity; Fuel; Solid waste; Energy 1. IntroductionCoal–water slurries (CWS) developed as a new alternative to fuel has opened newavenues in the utilisation of coal fines that can avoid prohibitive cost of dewatering.A typical CWS consists of 60–75% coal, 25–40% water and about 1% chemicaladditives. The effects of a number of variables, such as the properties of the coal, theparticle sizes and their distribution, the type and the amount of chemical additives, themethod of preparation of the slurry and the effect of its rheological properties on thebehaviour of CWS are very important [1,2].

  • the effect of chemicals on the viscosity and stability of coal water slurries
    International Journal of Mineral Processing, 2003
    Co-Authors: H Dincer, Feridun Boylu, Ayhan Ali Sirkeci, G Atesok
    Abstract:

    Abstract In this study, the effects of different chemicals that were used as dispersing agent and stabiliser on the stability and viscosity of coal–water slurries have been investigated. In the experiments, anionic type of chemicals—polyisoprene sulphonic acid soda (Dynaflow-K), a derivative of carboxylic acid (AC 1320) and naphthalenesulfonate–formaldehyde condensate (NSF)—were used as dispersing agents and the stabiliser was the sodium salt of carboxymethyl cellulose (CMC-Na). The coal sample used was a bituminous coal (thermal code no. 434) of Turkish origin, with medium volatile matter. The results of the experiments showed that polymeric anionic dispersing agents such as Dynaflow have much greater effect on the viscosity and the stability of coal water slurry.

  • the effect of coal properties on the viscosity of coal water slurries
    Fuel, 2002
    Co-Authors: G Atesok, Feridun Boylu, Ayhan Ali Sirkeci, H Dincer
    Abstract:

    Abstract Studies on coal–water slurries (CWSs) have been conducted for many years to replace fuel oil. In this research project, the effect of coal properties on CWSs have been investigated using two Turkish coals of different ranks and a Siberian bituminous coal. Physical, chemical and surface properties of coal samples were determined. Furthermore, adsorption tests were carried out in order to put forward the effect of additive adsorption on the viscosity of CWSs. Viscosity measurements were realized for CWSs of various solid ratios by weight that were prepared using coal samples having mean particle sizes of 19, 35 and 50 μm.