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Materials and Technology. Waste Heat Recovery Systems – Efficiency and Energy Saving

Publication in Metal Supply and Sales Magazine, Issue No.11, 2021
Pages 154-155
KALUGIN’s Waste Heat Recovery Systems – Efficiency and Energy Saving 
Ms. Marina Kalugina, KALUGIN’s General Director, talks about technical capabilities of waste heat recovery systems (WHRS) which can provide energy saving and improved operational efficiency of steel plants. 
For more than 20 years already KALUGIN Company has been engaged in design engineering and construction of hot blast stoves of top combustion design (Kalugin Shaftless Stoves) and implementation of different waste heat recovery systems in metallurgical production.
Wide spread of our technologies and demand for our equipment in the Russian and international markets provide strong evidence that their use provides an increase in energy efficiency and environmental performance of current metallurgical production in the best way.
Waste heat recovery systems are one of the company’s know-hows which allows our customers to reduce fuel consumption in a very short time. These systems are used to heat combustion air and blast-furnace gas flowing through the heat-exchanger up to 150-180°С using the heat of waste gases from the hot stove with the maximum temperature of 300°С.
The installed waste heat recovery system allows BF operators to save up to 40% of useful energy and use it further in new production cycles.
Moreover, the use of pre-heated air instead of ambient air improves fuel combustion and reduces its chemical and mechanical underburning.
It should be noted that implementation of the WHRS makes it possible to achieve the following economic and environmental parameters: 
amount of heat received during combustion increases by 10–15% only due to addition of waste gas heat;
annual saving of energy resources due to WHRS use can be up to 15,000 tons of coal equivalent;
fuel saving leads to reduction in heat emissions into the atmosphere and consequently reduction in emissions of CO, NO2 and other harmful substances.
At present, KALUGIN Company produces several types of heat exchangers:
conventional tube recuperators;
heat pipe heat exchanger;
plate type heat exchangers.
All the heat-exchangers are capable of long operation at the temperatures of 300-600°C. Moreover, due to a low aerodynamic resistance of gases flowing along the air and gas ducts the waste heat recovery systems designed by KALUGIN have a high efficiency factor and corrosion resistance.
In each new project the company’s engineers always consider such factors as location of the heat exchanger in the aggressive environment and possibility of its integration in the existing utility lines. After completion of expert evaluation, depending on the data received, they calculate the optimum design of the waste heat recovery system which shall meet the Customer’s production objectives and commercial interests in the best way.
For this purpose, the company’s engineers perform the entire complex of heat engineering calculations and then develop a set of design engineering documentation. During construction they provide necessary control over erection of the heat exchangers at the site. Furthermore, our company consults the customers both on current issues and during the entire period of the system service life. 
Thus, the systematic approach and maximum control over workmanship allow us to develop and implement projects providing the maximum efficiency of the waste hear recovery systems.
It should be noted that heat pipe heat exchangers are in highest demand among the customers due to their multifunctionality and low price. Heat exchangers of this type have the smallest dimensions and can be easily integrated in complicated utility lines.
The design of the waste heat recovery system with this type of heat exchangers is optimally calculated for maximum strength and reliability. It takes from 6 to 9 months from project development to its construction and integration into the production system. The calculated service life of the heat pipe heat exchangers is minimum 10 years. In other words, the customer can start receiving steady profits from investments already in one year after WHRS commissioning.
Thus, implementation of the waste heat recovery systems designed by Kalugin can be one of the most efficient operational options of current production. For example, the metallurgists successfully use this equipment to decrease addition of natural gas, which allows them to reduce production cost of their products. 
At present, KALUGIN Company has already constructed and implemented more than 70 waste heat recovery systems with heat exchangers of different design. Thus, 40 WHRS based on heat pipe heat exchangers have been constructed at Chinese steel plants and 12 WHRS (among them six WHRS based on heat pipe heat exchangers). 14 projects have been implemented in India, two projects in Turkey and Syria each and onу project in Ukraine.
The waste heat recovery systems can be efficiently used not only in metallurgy but also in thermal and electrical energy industry, machine building, production of construction materials, chemical and petrochemical industry – everywhere where low-grade waste gases with the temperature up to 300°С are generated.
In conditions of constant growth of prices for energy resources and strengthening of environmental requirements, implementation of waste heat recovery systems will enable to settle key problems of modern production: reduction in consumption of expensive energy resources and significant reduction of emissions into the environment. 
Thus, KALUGIN’s engineers will continue sharing their professional experience in settling problems related to energy saving and higher efficiency of modern metallurgical production. At the request of a potential customer our engineers will analyze his needs and provide required solutions.  
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