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Technology of Cement Production: Issues and Options

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Technology of Cement Production: Issues and Options TECHNOLOGY OF CEMENT PRODUCTION: ISSUES AND OPTIONS FOR DEVELOPING COUNTRIES by RIZWAN IBRAHIM B.S. With Honors in Civil Engineering, Syracuse University (1981) Submitted to the Technology and Policy Program in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN TECHNOLOGY AND POLICY at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY February, 1986 @) Massachusetts Institute of Technology 1986 Signature of Author Department of Civil Engineering February 28, 1986 Certified by Professor Fred Moavenzadeh Thesis Supervisor Accepted by Professor Richard de Neufville Chairman, Technology and Policy Program -2- TECHNOLOGY OF CEMENT PRODUCTION: ISSUES AND OPTIONS FOR DEVELOPING COUNTRIES by RIZWAN IBRAHIM Submitted to the Technology and Policy Program on February 28, 1986 in partial fulfillment of the requitements for the Degree of Master of Science in Technology and Policy ABSTRACT The purpose of this study is to review the technological options available for producing cement, to discuss the economics of the various options, and to assess how the policy framework in the developing countries influences-the selection of appropriate technology for cement plants. A review of the technical literature was undertaken to determine the leading technologies for large and small-scale cement plants. The economics of the various options is discussed with emphasis on energy and transportation requirements. A study of the experiences of the World Bank in regard to cement policy in developing countries is taken to outline the'mportant issues and policy instruments. The principal conclusions of the study are that the technology of cement production is flexible with regard to different raw material and market conditions. Freight equalization, price controls and other subsidies are often used to distort markets in the develbping world, thereby leading to selection of inappropriate technology for cement plants in a country. By exercising a free market approach and by concentrating research and development funds on small-scale cement plants, the developing countries together with international development agencies and the major suppliers of cement plants can improve the selection of appropriate technology for their cement plants. Thesis Supervisor: Dr. Fred Moavenzadeh Title: Professor of Civil Engineering -3- ACKNOWLEDGMENTS I am grateful to the many individuals whose contributions of time and energy made it possible for me to complete this work. I would like to thank my advisor, Dr. Fred Moavenzadeh, for his support and guidance throughout the research and writing phases of the work. Mr. J. Christian Duvigneau and Dr. Charles Weiss of the World Bank deserve many thanks for assisting me in my research, and for providing valuable comments on the economic and policy issues discussed in the text. I am particularly indebted to Marshall Bear, Carlos Lola, and Diana Ingraham of AT International for their continual support of my research on small-scale cement plants. Christopher Hennin of the World Bank graciously offered his assistance throughout the research phase and for this I am particularly thankful. I also thank Mr. Mogens Fog of the World Bank for sharing his technical expertise with me and I am grateful to Margaret Bergman for assisting me with the editing of the text. Finally, I would like to dedicate this work to my parents, whose love, support, and affection have always been a source of inspiration and encouragement in all my pursuits. -4- TABLE OF CONTENTS PAGE: List of Tables................................................... 6 List of Figures. ................. a..............................8 CHAPTER 1.0 INTRODUCTION..................................................... 10 1.1 Objective................................................. 13 1.2 Organization of Study .................................... 13 CHAPTER 2.0 AN OVERVIEW OF CE•IENT TECHNOLOGY ................................. 20 2.1 What is Cement? ............................ ...... 20 2.2 Historical Development of Cement Technology............... 20 2.3 Raw Materials ........................................ 24 2.4 Processing of Raw Materials in the Kiln .................. 26 2.5 Portland Cement and other Cement End-Products............. 27 2.6 Environmental Issues................................. 33 CHAPTER 3.0 STATUS OF TECHNOLOGY AND EQUIPMENT IN LARGE-SCALE PLANTS. ......... 38 3.1 What is Large Scale? ............... ... 38 3.2 Quarrying and Crushing....... ......................... 39 3.3 Raw Material Handling and Storage ........................ 42 3.4 Raw Mix Grinding........................................... 43 3.5 Homogenization of the Raw Mix.......................... 47 3.6 Clinker Production......................................... 51 3.6.1 Wet Process.........e............................... 51 3.6.1.1 Semi-Wet Process ............................ 53 3.6.2 Dry Process......................... ............... 53 3.6.2.1 Semi-Dry Process............................ 54 3.6.2.2 Preheaters.................. .. ............. 55 3.7 Clinker3.6.2.3 Cooing.............6..... Precalciners....................... ................. 6258. 3.8 Clinker Grinding................ .. ..... ... ....... 64 3.9 Packing and Dispatching .............................. 64 3.10 Environmental Control .................................... 66 CHAPTER 4.0 STATUS OF TECHNOLOGY AND EQUIPMENT IN SMALL-SCALE PLANTS.......... 106 4.1 What is Small Scale?...... ........ s..*.....*.106 4.2 Survey of Available Technologies.......................... 107 4.2.1 Vertical Shaft Kiln................ .................... 107 4.2.1.1 Raw Materials and Fuel Preparation .......... 108 4.2.1.2 Kiln Design Packages........................ 111 --;L·. -5- Table of Contents PAGE: 4.2.2 Small Rotary Kiln................................... 120 4.2.3 Fuller-Pyzel Fluidized-Bed Process.................. 122 4.2.4 Reba Flame Sintering-Grate Process.................. 124 4.2.5 Lurgi Sintering-Bed Process.......... .............. 125 CHAPTER 5.0 ISSUES IN THE ECONOMICS OF CEMENT PLANT TECHNOLOGY............... 148 5.1 Economies of Scale....................................... 148 5.2 Energy.................................................... 151 5.2.1 Comparative Energy Consumption in Different Processesl52 5.2.2 Energy Consumption in Developing Countries.......... 157 5.2.3 Fuel Substitution................ ........ .. ..... 159 5.2.4 Conservation ................ ....................... 161 .5.2.5 Summary............................. 164 5.3 Transportation............................................ 166 5.4 Capital and Labor....................................... 170 CHAPTER 6.0 THE POLICY FRAMEWORK FOR CEMENT IN DEVELOPING COUNTRIES.......... 190 6.1 Instruments Affecting Competition in the Industry......... 190 6.1.1 Licensing and/or Direct State Ownership. ........... 190 6.1.2 Market Segmentation and Import Controls............. 192 6.1.3 Interest Groups..................................... 192 6.2 Instruments Affecting Profitability and Factor Utilization 194 6.2.1 Price Controls and Surveillance Systems............. 194 6.2.2 Freight Equalization........ .c............gg....... 198 6o2.3 Other Subsidies....... ............................ 200 6.3 Quality Issues...................cc.................... 201 6.4 Market Failures ...... .................................. 205 6.5 Policy Options......................................... 208 CHAPTER 7.0 CASE STUDIES................ ......... ...... .................... 214 7.1 India..................................................... 214 7.2 Mali. ....... .............................................. 222 7.3 Nepal..................................................... 227 CHAPTER 8.0 CONCLUSIONS AND RECOMMENDATIONS ................................ 249 BIBLIOGRAPHY..................................................... 253 -6- List of Tables Chapter 1 1.1 World trade in cement, 1970-1981. 1.2 World production, consumption and international trade in cement. 1.3 Cement production and consumption in selected countries. 1.4 World cement production, 1983 and clinker capacity, 1983, 1984, and 1990. 1.5 Summary of forecasts of U.S. and rest of world cement demand, 1990 and 2000. Chapter 2 2.1 Oxide composition of normal portland cement. 2.2 Principal compounds of portland cement. 2.3 Representative average compound composition for five types of portland cement. Chapter 4 4.1 Global survey of vertical shaft kilns in operation. 4.2 Estimated production in mini cement plants in China. 4.3 Comparison of different technologies for mini cement plants. Chapter 5 5.1 Estimations of cost per ton of installed capacity. 5.2 Variations of manufacturing costs with size of cement plant. 5.3 Economies of scale in the cement industry. 5.4 Economies of scale. 5.5 Energy consumption by manufacturing stage. 5.6 Comparative thermal energy consumption in various pyroprocessing systems. 5.7 Comparative features of different cement production technologies. 5.8 Energy requirements of the fluidized bed kiln. 5.9 Energy consumption in the cement industry in selected developing countries. 5.10 Energy consumption in the cement industry in selected countries 5.11 Average electrical energy consumption in cement manufacture in selected industrialized countries. 5.12 Shares of different fuels in thermal energy consumption in cement. 5.13 Approximate rates of return on oil to coal conversions. 5.14 Comparative costs/benefits of alternate conversions. 5.15 Production workers related to plant capacities
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