• Energy Research

AbstractCement manufacturing is a high energy consuming and heavy polluting process. To reduce the energy and environmental costs cement producers are currently using a blend of alternative fuels with conventional fossil fuels. Alkaline environment, high temperature and long processing time allow cement kiln to burn a wide range of alternative fuels including waste and hazardous materials. This paper summarizes and reviews literatures on the usage of different types of alternative fuel and their impacts on the plant performance. The past research suggests that the maximum benefit can be derived by using an appropriate blend of different types of alternative fuels together with fossil fuels. However, the studies on quantification of appropriate mixing ratio of different alternative fuels to increase the plant performance are scant. Further study is required to determine the correct blending ratios. This literature review is focused on the relationship between performance and blending of different alternative fuels used by leading cement manufacturing groups.

Rasul, M orcid:0000-0001-8159-1321 ; Cement manufacturing is an energy-intensive and heavy pollutant emissions process. Waste-derived alternative fuels are widely used to reduce the pollutant emissions and the use of fossil fuel. Within the cement kiln, it requires about 40-50% of total thermal energy to complete the complex chemical reactions of clinker formation. High kiln temperature and the intrinsic ability for clinker to absorb and lock contaminants into the clinker allow the kiln to burn a wide range of alternative fuels. Agricultural biomasses are one of the emerging alternative fuels in the cement industry due to their availability and very low price. This chapter presents the effects of using agricultural biomasses as alternative fuels on the energy efficiency and emission from the kiln by using Aspen Plus process modeling. The suggested model is verified against measured data from industry and data available in literature. Results show that up to 3% of energy efficiency improvement along with 3.5% reduction of CO2 can be achieved through the utilization of various agricultural biomasses.

AbstractCement manufacturing is an energy intensive and heavy pollutant emissions process. It is accountable for CO2, NOX, SO2 emissions and some heavy metal discharge from the manufacturing process which causes severe greenhouse effects. Waste derived alternative fuels are widely used for substituting the thermal energy requirement from fossil fuels and reducing the pollutant emission. In the current study, a process model of the preheater tower is developed using Aspen Plus simulation software based on the combustion mechanism. Preheater tower is part of the modern energy efficient cement plant which is responsible for most of the CO2 release as the calcination of the raw material occurs at high temperature in this section. The model is verified against measured data from industry and data available in the literature. This paper presents the effects of the flow rate of waste derived fuels on the energy efficiency and emission from the preheater tower. Three different waste derived fuels, namely tyre derived fuel, meat and bone meal and refuse derived fuel are considered for this study. Fixed substitution rate of conventional fuel by the alternative one has been considered to identify the differences among the selected alternative fuels. Results show that maximum 3% increase of energy efficiency and 2.5% reduction of CO2 can be achieved by using tyre for about 25% of thermal energy requirement. Simulation results presented in this paper offer a guideline for implementing selected waste derived fuels in cement industry.

Abstract Cement manufacturing is one of the leading energy consuming and heavy pollutant processes which is accountable for CO2, NOX, SO2 emissions and some heavy metal discharge from the pre-calciner kiln system. In past few decades there has been an enormous amount of researches to reduce the energy and environmental cost by using alternative fuel and raw material. In recent years utilisation of alternative fuels in cement manufacturing has gained a wide attention due to its effectiveness in substituting the thermal energy requirement from fossil fuels and reducing the pollutant emission. Alkaline environment, high temperature and long residence time allow rotary kiln to burn a wide range of waste and hazardous material. Recent development on the usage of alternative fuels in cement industry is presented in this paper and many of the research articles relevant to this study is reviewed and discussed. Studies on the impact of alternative fuels on environmental emission have also been included in this review. This paper provides a thorough understanding and status of alternative fuels and their usage in cement industry and highlights their positive impact on environment. This study offers a guideline for planning and implementing alternative fuel usage in cement industry around the world, particularly in Australia. The paper revealed that meat and bone meal (MBM) could be the best alternative fuel option for Australia with a substitution rate of 40%.

Akbar, DH orcid:0000-0002-2269-5056; Ashwath, N orcid:0000-0002-4032-4507; Rolfe, JC orcid:0000-0001-7659-7040 ; Currently, the world is in search of bioethanol feedstock that does not compete with the human food supply and prime agricultural land. A native plant of Mexico, Agave tequilana, is one such feedstock. This plant can grow in arid, semiarid, or marginal lands with minimum rainfall and fertilizer and without competing with the current agricultural feedstocks [13, 14]. To date, only first-generation biofuel, especially bioethanol, is used in commercial production. However the second-generation biofuels may produce cost-effective fuels, but this is yet to be demonstrated as this option is still in precommercial or research and development phase [12]. This chapter aims to review the trends of bioethanol production and to explore the key factors affecting the commercial viability of producing first-generation bioethanol, with a particular focus on Australia. This chapter begins with the categorization of biofuels and bioethanol followed by a description of bioethanol feedstocks, the factors affecting commercial viability of bioethanol production in Australia. The chapter concludes with a review of costs and benefits of bioethanol production in Australia.

AbstractThe manufacture of Portland cement is an energy intensive process. It produces significant pollution and uses large amounts on non- renewable resources. With increasing pressures to reduce greenhouse gas emissions due to cement manufacture, research and development of fuel alternatives and their effect on the manufacturing process has become an industry focus. The inherent properties of sintering cement in a rotary kiln allows for a large number of fuels to be burnt which are normally prohibited for use as fuel in other processes. To examine the suitability of a fuel, process modeling and simulation can be undertaken to predict the final impact of that fuel on kiln performance and greenhouse gas emission. With an accurate model and sufficient data, it is possible to conduct simulations for a wider range of alternative fuels. This paper discusses and summarizes the simulation results of three alternative fuels, namely spent carbon lining, used industrial lubricants and used tires, for identifying the most effective fuel source among these three. Among the selected fuels used, industrial lubricant is found to be the best option regarding the CO2 emission, while the spent carbon lining is the worst one. In contrast, feed material requirements can be reduced by up to approximately 15% by using spent carbon lining. Further research is recommended to justify the findings.

Cement manufacturing is one of the most energy intensive processes and is accountable for substantial pollutant emissions. Increasing energy costs compel stakeholders and researchers to search for alternative options to improve energy performance and reduce CO2 emissions. Alternative fuels offer a realistic solution towards the reduction of the usage of fossil fuels and the mitigation of pollutant emissions. This paper developed a process model of a precalciner kiln system in the cement industry using Aspen Plus software to simulate the effect of five alternative fuels on pollutant emissions and energy performance. The alternatives fuels used were tyre, municipal solid waste (MSW), meat and bone meal (MBM), plastic waste and sugarcane bagasse. The model was developed on the basis of energy and mass balance of the system and was validated against data from a reference cement plant. This study also investigated the effect of these alternative fuels on the quality of the clinker. The results indicated that up to a 4.4% reduction in CO2 emissions and up to a 6.4% reduction in thermal energy requirement could be achieved using these alternative fuels with 20% mix in coal. It was also found that the alternative fuels had minimum influence on the clinker quality except in the case of MSW. Overall, MBM was found to be a better option as it is capable on reducing energy requirement and CO2 emissions more than others. The outcomes of the study offer better understanding of the effects of solid alternative fuels to achieve higher energy performance and on mitigating pollutant emissions in cement industry.