The Austrian gasket manufacturer KLINGER Dichtungstechnik produces its PTFE gaskets with filler material under the brand name KLINGER®top-chem. In order to enhance its product offering and to provide customers with additional benefits, the company is now investing into a regenerative thermal oxidation plant. It will ensure that no solvent residues are emitted and that waste heat can be fed back into the process.
Visitors to the KLINGER headquarters in Gumpoldskirchen, Lower Austria, will most surely have noticed a new construction site next to the road that runs in parallel to the premises. “This is where our new regenerative thermal oxidation plant will be located,” confirms Michael Sautter, Managing Director (commercial) of KLINGER Dichtungstechnik. And the plant, which has roughly the dimensions of a single-family home, is already beginning to take shape. Designed by the industrial combustion systems expert CTP-DUMAG, a next-door neighbor of the KLINGER Group, it is scheduled for completion in the first quarter of 2020.
Regenerative thermal oxidation plant promises efficiency gains and increased competitiveness of KLINGER®top-chem
Asked about the reasons for the new plant, Mr. Sautter explains: “Our regenerative thermal oxidation plant is part of a new manufacturing process for our high-performance PTFE sheets with fillers. It will allow us to increase our material efficiency as well as our annual sheet capacity. Furthermore, it will enable us to re-use our waste heat. This is in line with our ‘Sustainability’ value, as it contributes to a resource conservation in our production.” According to the managing director, these improvements will benefit the customer and simultaneously increase the competitiveness of KLINGER®top-chem on the market.
New process revolutionizes KLINGER®top-chem production
Ernst Schäfer is KLINGER Dichtungstechnik’s Managing Director (technology). He is in charge of the technical details of the project. “Our new manufacturing solution includes new process technologies and we have also developed high-performance tempering and sintering ovens to achieve our goals. The reason for our regenerative thermal oxidation plant, however, is a new solvent we have introduced. Our previous version had reached its operational limits, resulting in bottlenecks and process efficiency potentials not being realized,” he explains, adding: “This is why we switched.” The Austrian clean air act, however, stipulates that this lubricant must be removed from the raw gas that is primarily created during tempering of the PFTE sheets. “We had two options,” remembers Ernst Schäfer, “either to opt for a thermal oxidation solution or take the path of regenerative thermal oxidation.” Although both options provide the legally required results, calculation models quickly highlighted a number of advantages that spoke loudly in favor of a regenerative approach. “The investment costs were admittedly significantly higher,” states Mr. Schäfer, “on the benefits-side, however, we found lower operating costs, significantly reduced CO2 emissions and less thermal energy demand.” The latter, by the way, is explained by the improved waste heat recovery, meaning that more excess heat can be fed back into the process.
Superior regenerative thermal oxidation
In the course of regenerative oxidation, the scrubbed gas, which is already solvent-free, transfers its heat to a regenerator, which in turn heats the raw gas at an average temperature of approximately 180 to 200 °C. The regenerators themselves consist of ceramic honeycombs, which can be used to store heat. A minor portion of the solvent removal already occurs at the regenerators. The majority of the oxidation process, however, takes place in the burner. “The heat return figure provided by the regenerative thermal oxidation process is significantly higher than the one offered by thermal oxidation. In fact, we require only very low volumes of natural gas to fire the burner – the temper process is almost autothermic,” explains Mr. Schäfer. Completing his tour of the technological highlights, Ernst Schäfer also points out the additional recuperator, which pre-heats the primary air: “Following its passage through the regenerator, the scrubbed gas transfers its heat to the primary air, which further reduces the energy demand of the overall drying process.” Next to significant energy savings, this also saves a considerable amount of CO2: At an operating grade of 100 percent, the savings amount to more than 150 tons per year.
Michael Sautter and Ernst Schäfer are both satisfied with the progress of their new plant. “We are very much looking forward to showing our customers the results of our redesigned manufacturing process for the KLINGER®top-chem product,” explains Mr. Sautter, “As a maintenance-free gasket that does not age, it is definitely a solution for industries where absolute durability and an extremely long service life are a must: for example in district heating.”