The objective of this case study was to evaluate the technical and economic feasibility of utilising waste heat generated in the ECO Elvac thermal oxidizer unit. The unit is located downstream of the curing oven in a KTL coating line. An engineering-driven approach formed the basis of the solution’s effectiveness. We leveraged our expertise in simulation and engineering design to confirm the exceptional return on investment.
Identification of energy losses
The initial state of the KTL coating line operation was characterised by energy inefficiency associated with the operation of the ECO Elvac thermal oxidizer unit. Waste heat generated during the curing process was discharged into a wet scrubber without any further use.
This situation represented significant financial losses, particularly in the context of rising natural gas costs. The objective of our proposal was to break this inefficient cycle and reintegrate the waste heat back into the company’s energy system.
Technical Solution and System Integration
The proposed measure consisted of implementing a flue gas-to-water heat exchanger with a nominal capacity of 150 kW into the existing hot water circuit of the gas boilers. Between the thermal oxidizer unit and the wet scrubber. The heat exchanger operates in parallel with the gas boilers and transfers heat directly into the existing distribution system, without the need for costly modifications to the existing infrastructure.
The system operates in a non-condensing mode with a standard estimated efficiency. Emphasis was placed on precise control settings, which are a critical factor in achieving the projected savings.
Risk Factors and Recommendations
Successful implementation of the proposed measure and achievement of the projected parameters require precise technical supervision of critical factors. In particular, it is necessary to verify the actual flue gas temperature through direct measurement and thoroughly assess the fan’s pressure reserve after integrating the heat exchanger into the system. It is also necessary to take into account that the selected non-condensing operation naturally limits the maximum achievable efficiency of the entire system. Proper configuration of the control system is an absolutely key factor in achieving the expected financial and energy savings.
Investment Costs and Return on Investment
Based on the calculations presented in the supporting documentation, the annual waste heat potential was determined. The total investment costs of the project include full implementation, from design documentation to installation. I.e. the supply of a flue gas heat exchanger, DN50 piping connections, valves, a circulation pump, a measurement and control system, design documentation, and installation work.
We conducted a precise calculation of flue gas flow rates and operating hours. The average savings potential ensures both simple and discounted payback of the initial total investment within a period of just 2 years. A high internal rate of return (IRR) is demonstrably achieved. The discounted cash flow analysis confirmed that the project generates a positive net present value (NPV) already within the first third of the expected lifetime of the technology, thereby minimising investment risk. This represents a highly efficient investment with a minimal risk profile.
Final Recommendation
The implementation of this measure represents a strategic step towards strengthening energy independence and reducing operating costs. The project is not only technically feasible, but due to its economic performance, it ranks among priority investments within the modernisation of industrial operations. Thanks to the short payback period and high internal rate of return, the project has been recommended for implementation.
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