Conventional and Alternative Sources of Thermal Energy in the Production of Cement—An Impact on CO2 Emission

Karolina Wojtacha-Rychter,Adam Smolinski,Piotr Kucharski

doi:10.3390/en14061539

Abstract

The article evaluates the reduction of carbon dioxide emission due to the partial substitution of coal with alternative fuels in clinker manufacture. For this purpose, the calculations were performed for seventy waste-derived samples of alternative fuels with variable calorific value and variable share in the fuel mixture. Based on annual clinker production data of the Polish Cement Association and the laboratory analysis of fuels, it was estimated that the direct net CO2 emissions from fossil fuel combustion alone were 543 Mg of CO2 per hour. By contrast with the full substitution of coal with alternative fuels (including 30% of biomass), the emission ranged from 302 up to 438 Mg of CO2 per hour, depending on fuel properties. A reduction of 70% in the share of fossil fuels resulted in about a 23% decrease in net emissions. It was proved that the increased use of alternative fuels as an additive to the fuel mix is also of economic importance. It was determined that thanks to the combustion of 70% of alternative fuels of calorific value from 15 to 26 MJ/kg, the hourly financial profit gain due to avoided CO2 emission and saved 136 megatons of coal totaled an average of 9718 euros. The results confirmed that the co-incineration of waste in cement kilns can be an effective, long-term way to mitigate carbon emissions and to lower clinker production costs. This paper may constitute a starting point for future research activities and specific case studies in terms of reducing CO2 emissions.

Highlights

Cement manufacturing constitutes a significant source of anthropogenic CO2 emissions both in the European Union and in the world [1]
After 2016, a slow increase in the concentration of carbon dioxide from clinker production was observed, again to the level of 11.29 million tons in 2019, which was conditioned by economic growth
3) indicate differencescomposition between invidual samples fuel, which may from the heterogeneous dividual samples of alternative fuel, which may result from the heterogeneous composiof the waste stream used for fuel production

Summary

Introduction

Cement manufacturing constitutes a significant source of anthropogenic CO2 emissions both in the European Union and in the world [1]. The sector is responsible for approximately 5–9 percent of worldwide emissions [2,3]. In 2010–2019, carbon dioxide coming from the Polish cement industry constituted about 2–3% of the country’s total CO2 emissions [4,5]. Between 2010 and 2016, the CO2 emission in the cement sector remained at an average level of 9.5 million tons, except for the increase to the level of 11.43 million tons in 2011, related to the record results in the construction industry in terms of the number of implemented projects. After 2016, a slow increase in the concentration of carbon dioxide from clinker production was observed, again to the level of 11.29 million tons in 2019, which was conditioned by economic growth. Based on the annual production of clinker and cement for this period [5], it can be estimated that circa 700–800 kg of CO2 was emitted per ton of clinker produced and about 500–700 kg of CO2 per one ton of cement produced

Methods

Results

Conclusion