Semih COŞKUN
Business Development Director
Sintek
The Importance of Energy Efficiency in the World
The world population has been increasing rapidly during this period and therefore the efficient use of resources has gained considerable importance for the future of humanity. 87% percent of people’s need for energy is met by coal, gas, and oil in this age where fossil fuels are primary energy resources (Milena Gonzalez, 2013). However, when we take a general look at the history of humanity, we see that people met their energy needs either by making fires or using renewable energy resources such as wind and water in between the industrial revolution of the 19th century and the era of coal- based vapor Technologies (Bithas, 2016). The transition to agricultural society and the rapid rise in the world population dramatically increased people’s need for energy and popularized the use of fossil fuels with high combustion efficiency (Krausmann, 2011). On the other hand, dependence on fossil fuels, which take many years to form and have a limited source, is not sustainable for human beings. For this reason, efforts are being made to reduce the use of fossil fuels by encouraging the use of alternative energy sources.The use of alternative and renewable energy resources supported by developed countries through incentives and R&D studies, in a sense, shows how developed a country is. Among the European Union countries, the use of alternative energy resources is at a level of about 27 percent in proportion to the overall (Eurostat, 2017). Energy efficiency and alternative energy resources are of vital importance for countries in keeping up with the ever-changing world and competing at the same level with developed countries.
Energy Use in the Cement Sector
The share of Turkey’s cement sector in industrial production is 3 percent (TOBB, 2012) and this makes the cement sector one of the leading sectors of the national industry. The industry share of the sector when it comes to total energy consumption is 17.5% percent and this rate makes the cement sector the second highest energy consuming sector after the iron & steel sector. In this energy-dense cement sector, an electricity of about 100-110 kWh and a fuel energy of about 2.5-4.0 GJ are required to produce one metric ton of cement. When we take a look at the cost components of the sector, we see that fuel expenses constitute the main spending item of the cement sector with a share of 38% percent. Among the most frequently used fuels are petroleum coke with 70% percent and coal with 28% percent. From this point of view, it can be said that the cement sector is currently dependent on fossil fuels. Electricity costs with a share of 21% percent are another one of the cost components. In total, energy costs with a share of 60% percent represent the largest share in total operational costs. Efficiency efforts and improvements in the field of energy will directly do well for our country considering the place of the sector in the Turkish industry and its energy cost.
The Use of Alternative Energy Resources in the Cement Sector
The sustainability of the energy efficiency motivation must be ensured by the cement industry, which is the pioneer in the technologies and processes used in our country. The efforts carried out in this sense are divided into two: substitution of alternative fuels and reduction of energy consumption through improvements to be made in technologies and processes. In the field of alternative fuel substitution, fuels used in place of coal and natural gas,– which are the primary fuels used in cement factories – can be listed as refuse derived fuels, solvents, end-of-life tires, bilge waste, waste oils, and treatment sludge with the appropriate calorific value in various domestic or different types containing components such as timber, textiles, and plastics. The following table shows the calorific values of alternative fuels compared to petroleum coke.
The alternative fuel substitution is at a level of 2% percent in the Turkish cement sector whereas in the world this rate is 12% percent, which is pretty higher than that of our country. With the use of waste as alternative fuel, we achieve a saving by reducing the usage of fossil fuels and help waste incinerated in 1400°C-furnaces be completely disposed of without any residues left and reduce CO2 emissions.
Here are the three advantages of waste incineration in cement factories:
1. A economic value is regenerated by using waste,
2. A reduction is achieved in CO2 emission values by decreasing the use of fossil fuels,
3. No ash residue is left behind and no emission is released to nature as a result of incineration procedures carried out at high temperature.
Another example regarding alternative energy resources in addition to refuse-derived heat is the recycling of the gas released to outside within the system as energy in systems generating energy from waste heat. Only a certain amount of the heat produced in the cement sector where thermal energy is a requirement can be used in the process and the remaining part suffers from a loss. This loss is generally released to the outside of the system through stack gases. The Waste Heat Recovery (WHR) system helps vapor be produced from hot gases released from chimneys and this leads to regeneration of energy. The general principle of the system is to produce vapor using gases released from chimneys, send that vapor to the turbine, generate electricity there with the help of a generator, and finally to cool off the hot water obtained from the turbine outlet and reintroduce this water to the system through chemical treatment. An electricity energy of 3 to 6 MW can be obtained in a clinker line with a capacity of 3,000 metric tons depending on the technology used and the humidity of raw materials.
The advantages of the system are as follows:
•It provides energy efficiency thanks to its fuel saving feature and helps to increase competitiveness as this energy efficiency helps with product costs,
• It reduces the heat in the chimney and, thus, decreases the load on equipment such as chimney and fan available in the process and extend the expected life of these equipment,
• It prevents thermal pollution by reducing the heat released to the atmosphere.
References
(2017, January). Eurostat: https://ec.europa.eu/eurostat/statistics-explained/index. php/Renewable_energy_statistics AYAN, S. (2013). Association of Turkish Building Material Producers (İMSAD) Sustainability Committee Sharing.
Bithas, K. (2016). Revisiting the Energy-Development Link: Evidence from the 20th Century for Knowledge-Based and Developing Economies. Krausmann, F. (2011). Growth in global materials use, GDP and population during the 20th century. Ecological Economics.
Milena Gonzalez, M. L. (2013, October 24). Worldwatch Institute: https://www. worldwatch.org/fossil-fuels-dominate-primary-energy-consumption-1 TÇMB (Turkish Cement Manufacturers’ Association) (2014). The Turkish Cement Sector’s Approach to the Use of Alternative Fuels and Alternative Raw Materials. Turkish Cement Manufacturers
TOBB (Turkish Union of Chambers and Exchange Commodities) (2012). Assembly Sector Report by the Turkish Union of Chambers and Exchange Commodities.TOBB.
