Utilization of waste heat from rotary kiln for burning clinker in the cement plant

Abstract

Abstract. Cement subsector next to the glass industry is counted among one of the most energy-intensive industries, which absorbs approx. 12-15% of the total energy consumed by the industry. In the paper various methods of energy consumption reduction of in the cement industry are discussed. Cement production carries a very large emissions of greenhouse gases, where CO 2 emissions on a global scale with the industry than approx. 5%. Great opportunity in CO 2 emissions reduction in addition to the recovery of waste heat is also alternative fuels co-firing in cement kilns [1], [2]. In the cement sector interest in fitting-usable waste energy is growing in order to achieve high rates of savings and hence the financial benefits, as well as the environment ones [3]. In the process of cement production is lost irretrievably lot of energy and reduction of these losses on a global scale gives a visible saving of consumed fuel. The aim of this study is to investigate the possibility of waste heat use in Rudniki Cement Plant near to Czestochowa. After analyzing of all waste heat sources will be analyzed the heat emitted by radiation from the surface of the rotary kiln at the relevant facility. On the basis of thermal-flow calculations the most favorable radiative heat exchanger will be designed. The calculations based on available measurements provided by the cement plant, a thermal power of the heat exchanger, the heat exchange surface, the geometry of the heat exchanger, and other important parameters will be established. In addition the preliminary calculations of hydraulic losses and set directions for further work will be carried out. Direct benefits observed with the introduction of the broader heat recovery technology, is a significant increase in energy efficiency of the industrial process, which is reflected in the reduction of energy consumption and costs. Indirectly it leads to a reduction of pollution and energy consumption.

Harvesting waste heat from cement kiln shell by thermoelectric system

“…Significant amount of the heat produced in the rotary kiln is lost from the kiln shell [1]. Different methods for waste heat recovery from the external surface of the cement kilns has been proposed in the past, but these approaches can only be used for heating fluids in heat exchangers for indirect energy harnessing [1][2][3][4][5][6][7][8][9][10][11][12].…”

Waste heat mapping: A UK study

“…Although the responses were helpful, the low response rate means that the information provided was of little use, as it is anecdotal and therefore cannot be used to create a complete picture of the industry. During the manufacture of bricks, temperatures differ according to whether the bricks are made from clay or shale, but final drying takes place at around 200 • C, dehydration at around 150 -1000 • C, oxidation from 500 -1000 • C and vitrification from 850 -1300 • C [51]. Therefore, further research needs to be done on ceramics manufacture in the UK to assess its potential for use in heat reuse schemes.…”

Thermal Management Systems and Waste Heat Recycling by Thermoelectric Generators—An Overview

“…Cement subsectors are considered among the most energy-intensive industries, which absorb about 12-15% of the total energy consumed by the industry [91]. This industry is perhaps one of the most polluting industrial sectors, producing about 7% of the man-made carbon dioxide emissions each year [92].…”

“…Commensurate with this, the calculations in a case study [94] showed that the mean daily heat loss via the calcination zone of a kiln shell with a production capacity of 2500 tons/day is about 140 GJ, attributing to radiation and convection with fractions of~54% and~46%, respectively. The industrial cement sectors have been considering recycling waste heat to achieve higher rates of energy conservation and, thus, financial and environmental advantages [91,[95][96][97]. Nevertheless, as mentioned above, any employed strategies for heat recovery need to avoid/minimize changes in the temperature distribution within the kiln shell.…”