- Written by Ted T Reese, Cadence Environmental Energy
The global demand for alternative fuels continues to increase and diversify. Cement companies are under increased scrutiny to deliver high quality products in a safe environment, while continuing to increase their efficiencies. The need to reduce kiln operating fuel costs therefore remain one of the largest goals for cement producers. Traditionally this has involved solid wastes, particularly from municipal sources. Here, however, Ted T Reese of Cadence Environmental Energy highlights the potential to use wastes from the oil refining industry as alternative fuels for cement production.
- Written by Maria del Mar Cortada Mut, Technical University of Denmark; Linda Kaare Nørskov, FLSmidth A/S, Denmark; Peter Glarborg and Kim Dam-Johansen, Technical University of Denmark
The cement industry has long been dependent on the use of fossil fuels, although a recent trend in replacing fossil fuels with alternative fuels has arisen.1, 2 However, when unconverted or partly converted alternative fuels are admitted directly in the rotary kiln inlet, the volatiles released from the fuels may react with sulphates present in the hot meal to form SO2. Here Maria del Mar Cortada Mut and associates describe pilot and industrial scale experiments focusing on the factors that affect SO2 release in the cement kiln inlet.
- Written by Peter Edwards, Global Cement Magazine
The Lafarge Mannersdorf cement plant in Mannersdorf, Austria, is one of two Lafarge facilities in the central European country. In this plant visit report, plant manager Dr Joseph Kitzweger provides a detailed run-down of the plant's history, production process, use of alternative fuels, environmental performance, products and distribution. Dr Kitzweger also gives his frank assessment of the Austrian cement market and his thoughts on the EU Emissions Trading scheme.
- Written by Martin Demuth, Davor Spoljaric, Johannes Rauch & Michael Potesser, Messer Group GmbH, Christoph Hochenauer, Institute of Thermal Engineering, Graz University of Technology
Oxygen-enrichment can lower production costs for many processes because fuel costs are continuously on the rise. Enrichment is used more and more frequently in combustion systems technologies like oxygen burners, oxygen lancing and other oxygen enrichment systems in order to raise productivity, save energy or enable the use of lower quality fuels. Messer Oxipyr® technologies are used to provide discrete oxygen-rich areas in furnaces to allow complete combustion of fuels or lowering of emission values. This article determines the possibilities for and the advantages of oxygen application in rotary kiln burners for cement clinker production based on Messer testing results and installations that include a unique way of atomising liquid waste fuels with oxygen.
- Written by M. R. Karim, M. F. M. Zain & M. Jamil, Universiti Kebangsaan Malaysia; F.C. Lai, Sika Kimia Sdn Bhd; M. N. Islam, Dhaka University of Engineering and Technology
Modern constructions demand a lot of cement, but OPC has a large negative impact on the environment, producing large amounts of CO2. With increasing demand, raw material prices increase and fuel resources are falling. As there is currently no viable alternative to OPC, research centres around the use of alternative fuels and supplementary cementitious materials. Here researchers from Malaysia and Bangladesh present ways to use biogenic wastes as an alternative fuel and as a novel binder.
OPC is a versatile and widely-used construction material but burning CO2-emitting materials at 1450°C produces a lot of CO2,1 which contributes to global warming.2 To get a sustainable solution to this problem, much research has been conducted towards the use of biogenic wastes in cement production. Examples include palm oil fuel ash (POFA)3,4, rice husk ash (RHA),5,6 sawdust ash/ash from timber (AFT)7 and bagasse ash8 as supplementary constituents of cement and concrete.
RHA is generated from the rice husk processing industry. POFA is a waste from the palm oil milling industry. AFT is a waste from wood mills and the fibreboard industry. All of these types of ash can be produced by burning the relevant material in a kiln or furnace at 500-600°C. Large amounts of POFA, RHA and AFT are produced in Malaysia every year but they are not used to a significant extent at present. In spite of the potential financial, technical and environmental benefits, these materials are currently dumped locally with no commercial return. It has already been proven that all of these waste materials contain a high amount of amorphous silicon dioxide (SiO2). This means that they could be used as pozzolanic materials in cement and concrete production.
Additionally, these biogenic agricultural wastes contain different proportions of cellulose, hemicellulose, lignin, ash, resin, wax/oils, water-soluble substances and moisture. Carbon, nitrogen, oxygen and hydrogen are the major constituent elements of these compounds. Small amounts of sulphur and chlorine and traces of others element are also present. Their volatile matter content is around 60%-75%. High ash content lowers the calorific value of residues while the presence of oil, resins and wax raises the calorific value. The heat potential of some of the selected agricultural wastes from the biomass are given in the literature.9-12
Energy from biomass plays a big role in energy demand worldwide, supplying 10% of the total energy demand.13 In addition, in this study it is presented that the proper direct burning of the biogenic waste can be used as alternative fuel in the cement industry without quality problems or performance deterioration. This has the potential to save energy compared to OPC production.
