Scholarly record

CEMENT PRODUCTION IN RUSSIA: BEST AVAILABLE TECHNIQUES AND OPPORTUNITIES FOR USING ALTERNATIVE FUELS

И. О. Тихонова

Abstract

Cement is the second most-consumed resource in the world, with more than 4 billion tonnes of the material produced globally every year. The cement production is considered to be one of major polluters regulated by Best Available Techniques (BAT) both in Europe and the Russian Federation. At the same time, cement industry generates greenhouse gases (GHG) emissions both of the ?energy? and ?process? origin. In Russia, climate legislation is just being formed, but operators of cement installations have already begun looking for economically feasible solutions for reducing CO2 emissions. In Europe, conventional fuels are often replaced by waste fuels, derived from pre-treated and sorted waste fractions including solid and liquid recovered fuels, and/or biomass. The use of waste (to partially substitute raw materials as well as conventional fuels) is considered to be BAT for the cement manufacturing process. For Russian cement plants, this fact opens economic advantages as well as opportunities for greening production, though practitioners are concerned about the possible growth in emissions of ?ordinary? pollutants such as sulphur and nitrogen oxides as well as dust. The article describes results of quantitative estimation of emissions (CO2, SO2, NOx) after the partial replacement of the natural gas with wood chips, wood powder and sunflower pellets (burnt exclusively in the calciner). The calculations were made under the assumption that the specific heat consumption (heat rate) does not change while obtaining 7 ? 15% of heat needed by burning the alternative fuel. The estimated data show that the replacement of natural gas with 7.5 ? 15% of alternative fuel leads to a decrease in the total end-of-pipe gas emissions by 0 ? 0.56% (mass) and 0.09 ? 1.04% (volume release). The use of wood chips in 7.5 to 15% amount out of the total heat rate for firing 1 kg of clinker leads to the decrease in total gas emissions (by mass) from the kiln system by 0 ?0.49%, SO2 emissions: by 0.16 ? 0.27%, NO2 emissions: by 0.29 ? 0.67% and NO emissions: by 0.25 ? 1.24%. Emissions of CO2 will reduce by 0 ? 0.52 % physically and 7.5 ? 15.5 % reporting wise. The use of sunflower pellets in 7.5 to 15% amount out of the total heat rate for burning 1 kg of clinker leads to a decrease in total gas emissions (by mass) from the kiln system by 0.28 ? 0.56%, SO2 emissions: by 0.55 ? 0.97%, NO2 emissions: by 0.48 ? 1.06, and NO emissions: by 0.43 ?1.54%. Emissions of CO2 will decrease by 0 ? 0.26%; for reporting purposes, the decrease will reach 7.5 ? 15.76 %. The use of wood powder in 5 to 15 % amount out of the total heat rate for firing 1 kg of clinker leads to the decrease in total gas emissions (by mass) from the kiln system by 0.23-0.68 %, ??2 emissions: by 0.25 ? 0.76 % while simultaneously increasing SO2 emissions by 0.23 ? 0.68 %. NOx emissions decrease in proportion to the amount of main process fuel burned in the nozzle of a rotary kiln. Since alternative fuels will be supplied to the rotary kiln zone with a temperature of 1100?1200 °C and excess air (oxygen) content in a vaporous phase, the phenol-formaldehyde resins within wood fuel additives will undergo the process of complete oxidative decomposition and combustion. No additional emissions of organic substances (phenol-formaldehyde resins decomposition products) are expected. Kiln dust emissions depend primarily on the efficiency of end-of-pipe techniques used to treat stack gases, and will not change when replacing natural gas with fuel additives. At the same time, using fuel additives will contribute towards reducing GHG emissions of cement production and meet requirements of the emerging GHG legislation (regulation system) to be introduced in 2019-2020.

Publication details

Back to publication list