Galina S. Nyashina

Environmental indicators of the combustion of prospective coal water slurry containing petrochemicals

Negative environmental impact of coal combustion has been known to humankind for a fairly long time. Sulfur and nitrogen oxides are considered the most dangerous anthropogenic emissions. A possible solution to this problem is replacing coal dust combustion with that of coal water slurry containing petrochemicals (CWSP). Coal processing wastes and used combustible liquids (oils, sludge, resins) are promising in terms of their economic and energy yield characteristics. However, no research has yet been conducted on the environmental indicators of fuels based on CWSP. The present work contains the findings of the research of CO, CO2, NOx, SOx emissions from the combustion of coals and CWSPs produced from coal processing waste (filter cakes). It is demonstrated for the first time that the concentrations of dangerous emissions from the combustion of CWSPs (carbon oxide and dioxide), even when combustible heavy liquid fractions are added, are not worse than those of coal. As for the concentration of sulfur and nitrogen oxides, it is significantly lower for CWSPs combustion as compared to coals. The presented research findings illustrate the prospects of the wide use of CWSPs as a fuel that is cheap and beneficial, in terms of both energy output and ecology, as compared to coal.

Environmental benefits and drawbacks of composite fuels based on industrial wastes and different ranks of coal

A promising solution to many problems that thermal power industry is facing today would be switching from conventional coal dust combustion to coal-water slurries containing petrochemicals (CWSP). Here, we perform an experimental study of the most hazardous anthropogenic emissions (sulfur and nitrogen oxides) from the combustion of high-potential CWSP. We identify the main benefits and potential drawbacks of using CWSP in thermal power industry. A set of components and additives to CWSP are explored that significantly affect the environmental and energy performance of fuels. The anthropogenic emissions from the combustion of CWSP made of widespread coal and oil processing wastes are no higher than those from coal dust combustion. Using specialized additives to CWSP, we can change the concentrations of NOx and SOx several times. The most appealing additives to CWSP are sawdust, straw, charcoal, limestone, and glycerol. They provide better environmental, economic, and energy performance and improve the rheological properties of CWSP. Waste oils and oil sludge added to CWSP may impair the environmental performance but boost the cost and energy efficiency. Using coal-water slurries containing petrochemicals as a fuel at thermal power plants is an environmentally friendly as well as cost- and energy-efficient way to recover industrial wastes.

Emissions in the combustion of coal and coal-processing wastes

Power stations based on traditional hydrocarbon fuels—in particular, coal—are characterized by considerable atmospheric emissions. In the light of the annual increase in coal consumption and the ongoing environmental deterioration, significant decrease in atmospheric emissions per unit mass of coal consumed must be regarded as a high priority. In the present work, SO2, CO2, CO, NO, and NO2 emissions from power plants around the world are analyzed. The emissions formed in the combustion of traditional types of Russian coal and their processing wastes (filter cakes) are compared. The benefits of using coal–water slurry containing coal-processing wastes at power plants are outlined.