Energy consumption is one of the largest cost components in the production of Portland cement. Energy is consumed through the fuel required to make the cement, as well as the electricity consumed to operate the manufacturing equipment. This paper discusses the fuel requirements for producing cement and demonstrates some simple techniques for assessing and improving thermal performance. The basic heat requirements for driving the chemical processes are the starting point for the assessment. These are found to be rather similar through-out the industry, with only minor differences between different facilities. Higher chemical variability increases the heat requirements as more heat is required for the reactions and the reaction temperatures are higher. Thermal efficiency is primarily determined by the thermal recuperation of heat contained in the fuel combustion exhaust gases and the intermediate product, clinker. This heat is recuperated in preheaters and clinker coolers respectively. The factors that drive efficient heat recuperation are discussed and simple performance assessment indicators provided. Operators who pay close attention to their thermal performance can reduce operating costs and obtain a competitive advantage in the market.
Mark Mutter and Lawrie Evans, JAMCEM Consulting, UK, explain the importance of adapting standard targets and practices to local plant conditions.
The article describes a method for comprehensive energy audit of the company. Recommendations are given on measurement and reporting, various possibilities and techniques to reduce energy consumption by enterprises are described. Examples of process modernization projects to reduce energy consumption are given.
The paper is devoted to optimization (including using computational aerodynamics) of the conditions for solid fuel combustion in rotary kilns. An example of a successful transition to a 100% combustion of petroleum coke with addition of 15% shredded tires into a kiln inlet is given. The aerodynamic calculations made it possible to determine the necessary parameters of the kiln system, providing a solution to the problem of slag buildup in the preheater.