ENERGY SUPPLY FOR CEMENT PLANTS IS SOLVED
The increase in coal prices, the main input fuel for cement production in recent years, has caused many difficulties for cement factories. From practice, Prof. Dr. Vu Thi Thu Ha and a group of scientists from the Key Laboratory of Petrochemical Technology (Ministry of Industry and Trade) have successfully researched and tested the multi-purpose additives FNT6VN and ECOAL. This is a solution using additives to control the fuel combustion process in the direction of increasing capacity, saving fuel, and reducing emissions to the environment. The multi-purpose additives are used in traffic, transportation and industrial activities.
Addressing real needs
As the main fuel accounting for about 40-45% of cement production costs, coal prices have been fluctuating in an upward direction in recent years, which has greatly affected the operations of cement production enterprises. In addition, high-quality coal reserves are decreasing, forcing industries to start using low-quality coal. Therefore, the trend of applying preparations to improve combustion efficiency in clinker kilns and decomposition furnaces is of great significance in the cement industry.
Currently, Vietnam has over 80 clinker kilns in operation, consuming over 10 million tons of coal each year. The Vietnamese Government has committed to "achieving net zero emissions by 2050" at COP26. Along with that, from January 1, 2026, along with iron and steel and fertilizers, cement will officially be taxed by the EU on carbon and cement manufacturing enterprises must make inventory reports and reduce greenhouse gas emissions according to Decision No. 01/2022/QD-TTg and comply with the Law on Environmental Protection, the Law on Economical and Efficient Use of Energy, etc.
Among the solutions commonly used by cement factories today are: Utilizing waste heat to generate electricity, circulating waste gas in furnace operations, recovering CO2 in production, and recycling raw materials... These solutions require a lot of time and additional investment capital to upgrade or convert infrastructure, equipment, and machinery. In addition, the management and appraisal capacity of financial institutions in the field of energy efficiency is limited, and lending mechanisms are not attractive enough to encourage businesses to invest in energy saving. These are barriers that have prevented the energy saving investment market from making a breakthrough in recent times.
In industrial production, the solution to improve the efficiency of solid fuel combustion by using fuel additives is considered a “soft” solution. Based on this practical basis, scientists at the Key Laboratory of Petrochemical Technology have proactively assessed the importance of the research and development process and the experimental application of additives on an industrial scale.
According to the assessment of the Research Group, each type of industrial equipment using energy has its own characteristics and each equipment/line (of the same type) is unique. However, to date, there has been no published scientific document on the commercial use of fuel additives, bringing about energy efficiency in cement production in Vietnam. Therefore, scientists believe that the study of the application of preparations to improve energy efficiency in clinker kilns, decomposition kilns and the analysis of their operating mechanisms have important practical significance in the cement industry.
Increase energy efficiency
Accordingly, scientists have researched and produced 2 sets of ECOAL and FNT6VN preparations. ECOAL is an additive that enhances energy efficiency by reducing energy costs and polluting gas emissions for coal-fired industrial furnaces, very suitable for application in coal burning processes and/or solid fuels replacing coal (biomass, waste, solid soot from tire pyrolysis...) in cement, thermal power, chemical, and metallurgical plants. ECOAL is also suitable for processes using gas as fuel.
Meanwhile, FNT6VN has the ability to improve energy efficiency and reduce environmental pollution from activities using liquid fuels (gasoline, diesel, furnace oil (FO oil, RFO oil, recycled oil, ...), cashew nut shell oil, biofuel.
With the above approach, the Research Team has applied the FNT6VN and ECOAL additives to the TH Group's TanThang Cement Plant. All products of TanThang Cement Plant are manufactured on the FLSmidth technology line (Denmark) - one of the latest generations of technology and equipment in the world. The clinker kiln using FLSmidth technology is a 2-support kiln, 5m in diameter, 60.7m in length, and 484 tons in weight (including 6 sections). The kiln is designed to be suitable for 4a and 5a coal dust fuel, but operates most stably with 4a fuel.
At TanThang Cement Plant, FNT6VN additive is used to mix with liquid fuel for the drying process of clinker kiln, while ECOAL additive is used in the digester and clinker kiln during the clinker production process. As a result, both preparations have brought about truly outstanding economic, technical and environmental efficiency.
Specifically, for clinker kilns in cement plants, after the kiln shutdown cycle (due to technical problems or maintenance to rebuild refractory bricks in the kiln), it is necessary to dry the kiln to the required temperature to be able to produce clinker. During this process, liquid fuel, usually diesel oil (DO), is sprayed directly into the combustion zone in the kiln. With the desire to reduce energy costs, at TanThang Cement Plant, the solution of using a part of alternative fuel, with a lower grade than low-cost DO oil, has been considered. However, these alternative fuels often come with the characteristics of being difficult to ignite, not burning completely, etc., leading to a low fuel replacement rate or an unstable kiln temperature raising process, making it difficult to operate.
According to Prof. Dr. Vu Thi Thu Ha, in the past, the option of burning 100% FIO oil could not be implemented because the oil had high viscosity, was difficult to ignite, and was difficult to increase the drying temperature according to the chart. In addition, the selling price of FIO oil is 50% compared to the selling price of DO oil, so the method of converting to burning FIO oil instead of DO saves 50% of the fuel cost for kiln drying, with the converted value in money (according to statistics from accounting) being 1.8 billion VND for kiln drying cost/year (For a cement factory with a capacity of 2 million tons/year). Not only that, the presence of FNT6VN in the drying oil shows many positive effects, such as not affecting the process of pumping oil to the oil nozzle; The oil burns well, without any unusual phenomena; Does not cause oil separation or any other side effects.
With ECOAL, when used at a ratio of one liter of additive for 150 - 200 tons of coal, TanThang Cement Plant has successfully converted from burning 4a coal dust to burning 5a coal dust with 32% carbon black (a product of the pyrolysis process of waste rubber tires).
The characteristics of carbon black fuel from the pyrolysis of waste rubber tires, used as an alternative fuel in clinker kilns, is that the price of carbon black is much lower than the price of coal, but the process of burning carbon black in clinker kilns causes kiln adhesion, making the fuel difficult to burn, thereby affecting the kiln productivity and the quality of clinker products.
According to the research team, that means that the higher the coal replacement ratio, the more economically efficient it is, but it is necessary to overcome technical challenges. With the economic and technical efficiency brought about by the use of ECOAL additives, TanThang Cement Plant has reduced fuel costs by approximately 170 billion VND/year. Not only that, when using ECOAL, the clinker kiln operates stably, there is no adhesion phenomenon, and no formation of "dinosaur egg"-like agglomerates. Moreover, the clinker has much better quality than when not using ECOAL (beautiful color (black), even, no yellow core). The kiln capacity is still guaranteed, and the capacity is not reduced when using ECOAL.
Monitoring of testing of the preparation in clinker kiln
On the other hand, when not using ECOAL, cleaning the smoke chamber is very difficult because the chamber is sticky with the components generated from running coal dust with pyrolysis coal. When using ECOAL additive, the sticky layer in the smoke chamber becomes porous, making cleaning the smoke chamber very easy.
The test results of clinker kiln lining bricks (alkaline bricks, produced in Vietnam) show that after a long period of using ECOAL product (about 8 months), the kiln brick layer and kiln concrete layer still have no problems related to quality degradation.
ECOAL not only helps the fuel combustion process to be thorough but also has the effect of reducing NO x emissions. Specifically, the average NO x emissions at the calciner and clinker kiln when not using ECOAL are 970 ppm and 1000 ppm respectively, reduced to 780 ppm and 800 ppm respectively when using ECOAL. The reduction in NO x in the exhaust gas while the coal combustion process is enhanced can be explained by the presence of the additive that enhances the decomposition of volatile hydrocarbons to promote the reduction of NO and NO 2 to N 2 . On the other hand, the components present in the additive when decomposing in the combustion chamber lead to the formation of reducing agents, which can also contribute to some extent to the reduction of NO x compounds .
ECOAL product helps increase combustion efficiency for poor quality coal that is difficult to ignite.
These results are extremely interesting and unique, the first time they have been successfully implemented in the world. The presence of ECOAL helps increase the combustion efficiency of poor quality coal that is difficult to ignite, thereby allowing the effective use of a mixture of 68% 5a coal and 32% pyrolysis coal, Prof. Dr. Vu Thi Thu Ha shared.
Up to now, many delegations of technical staff from cement factories have visited and learned the experience of using FNT6VN and ECOAL products on the clinker production line of TanThang Cement Plant. At the same time, some cement factories have applied the additive products in the production process and achieved the desired results. Most recently, a customer using the additive not only reduced fuel costs by increasing combustion efficiency, but also solved the problem of kiln adhesion due to the use of biomass fuel, increased kiln capacity, and improved the quality of clinker.
Source: ximang.vn
