Combustion of water and coal suspension fuels of low-metamorphized coals

Abstract

Results are given for an experimental study of ignition and stabilization of burning water and coal suspensions prepared from coal of a low stage of metamorphism based on brown coals. Recommendations are given for improving the technology of preparation and burning of water and coal fuel.Currently in view of a shortage of liquid and gaseous fuels in the market (this is reflected in their cost) in Russia, and in other CIS countries and abroad, there is an increase in the interest of using in small and medium power generation coal and nontraditional fuels, i.e., waste materials of coal concentration production, sludge deposits, etc.In the near future, an increasing role is predicted for coal in the fuel and power generation balance of the country, and this is due to its large reserves. However, ecological limitations (particularly after ratification of the Kyoto Protocol) requires development and introduction of new ecologically clean coal technology, providing a high complete use of the fuel with the maximum low harmful discharge into the environment [1,2].In view of this, theoretical laboratory and test industrial studies are important with the aim of creating competitive ecologically clean processing technology for coal and utilization of waste materials in the form of coal fuel suspensions.A fuel suspension is a composite dispersed system consisting of a solid phase in the form of finely-dispersed coal and a liquid medium (water, alcohol, hydrocarbons, and oil processing products).In the last decade in many countries of the world there has a been a considerable amount of work for preparing water and coal fuel suspensions (WCF) and its use in power generation. In Russia and abroad, a series of manufacturing technologies have been developed for WCF, its transportation, prolonged storage, and combustion (gasification). Studies have been carried out for burning WCF in operating power generation units of different types. However, problems have not been resolved for complete (up to 3.0%) demineralization (enrichment) of coal and preparation of stable fuel of highly enriched coal.In accomplishing technology for thorough demineralization of coal a problem arises of preparing and utilizing the accompanying fine carbon slurries with an ash content of more than 20%. In order to resolve this problem it is necessary to develop technology for preparing coal fuel suspensions from these coal slurries for use in low and medium-capacity boilers, in boiler units and in industrial enterprises.The main tendencies in the development of technology for preparation of water and coal suspensions (WCS) are preparation of a suspension satisfying the requirements with respect to ash content, concentration, viscosity, fluidity and stability; reduction of the energy demand in producing a WCS; a reduction in the consumption of surfactants (SAS).Development of thermal power generation is connected to a considerable extent with use of low quality coal. During combustion of this coal there is formation of considerable amount of ash, that gives r...

Determination of Sectional Constancy of Organic Coal-Water Fuel Compositions

“…Obtained experimental data correlate well with data from [2][3][4][5][6][7][8][9][10]. Type of the dependence determined in experiments is similar to that one presented in [2][3][4][5][6][7][8][9][10].…”

“…Type of the dependence determined in experiments is similar to that one presented in [2][3][4][5][6][7][8][9][10]. Thus, in addition to the already known plasticizers, it is appropriate to apply as stabilizers the waste of petroleum-derived products, as well as oil refining, chemical and energy industries.…”

“…According to review of publications [1][2][3][4][5][6][7] we carried out a comparative analysis of known reagents-plasticizers with that one considered in the present work (based on used motor, turbine and transformer oils).…”

Coal-water suspensions: preparation, properties, characteristics (a brief overview)

“…В современной литературе результаты исследований свойств и характеристик ВУС можно разделить на следующие направления: приготовление, реологические свойства, распыление, зажигание и горение, экологические показатели. В качестве основной компоненты ВУС используют уголь [17] или отходы угольных обогатительных комбинатов -фильтр-кек [18]. В качестве основной жидкой компоненты применяется вода.…”

Rheological properties of coal water slurries containing petrochemicals

“…Coal fuels are notorious for their drawbacks [5][6][7][8] as compared to oil and gas. First, coal combustion produces maximum anthropogenic emissions and ash residue.…”