Why the foundry Lößnitz has invested in modern filter technology?
Lößnitz Foundry - A filter that could cope with these emissions first needed to be invented.
Lößnitz's foundry produces many tons of tools for Porsche Toolmaking, and for vehicles made by BMW, Daimler, Volkswagen, etc. The long-established company is an industrial heavyweight and an important employer in the region. But its positioning in the middle of the town had reached a breaking point.
When casting the huge tools, the filler from the large moulds evaporates, giving rise to a high air load of particulate matter, soot and odours.
In the past, this had led to tensions in the neighbourhood of the factory. The measurements of the Saxony State Office for Environment, Agriculture and Geology showed two years ago that the foundry caused a markedly increased environmental impact on days on which it operated. Although these were not deemed serious, measures were called for.
Expansion of production - and elimination of emissions
In 2014, the company took the decision to increase production capacity - while simultaneously comprehensively redeveloping the casting hall. A new filter technology for the filtration of large amounts of particulate matter needed to be installed, and, additionally investments needed to be made in the elimination of gas emissions and unpleasant odours.
As a first step, the hall was sealed. As a result, emissions could no longer diffuse through openings. Likewise, investments were made in modern environmental filter technology and in the optimum supply of clean fresh air to the employees working in the hall. The heat for the temperature control of the supply air is recovered from the excess heat of the furnaces in the heating period.
The exhaust gas values clearly fall below the limit values
"In the future, emissions will be significantly lower than the permissible limits," says Martin Boxhofer, project manager at Kappa. He was responsible for the foundry during the construction of the exhaust gas purification plant. "Kappa undertook pioneering work during the project's execution. At first we simply had no solution. Only Kappa was able to construct a customized system for us," says Frank Kattermann, former Managing Director of Gießerei Lößnitz GmbH. "An installation like this does not yet exist anywhere else in Germany. We assume that it's also a first for Europe as a whole."
Sand and gravity casting releases emissions
Sand and gravity casting release large quantities of particulate matter and tertiary amines. To date, solutions for the efficient and economic separation of these emissions lacked. Despite the difficult situation, Gießerei Lößnitz GmbH began to implement an exhaust air purification project to optimally protect employees, residents of the neighbourhood, and the environment.
Together with Kappa, a system has been developed that efficiently and economically separates both emission types - fine dust and odours. At the core of the plant lies the Kappa Ekon® de-dusting system. This is a completely new filter system for the separation of industrial dusts. The Kappa Ekon® revolutionizes the construction of large dust removal systems by taking up half the space of conventional systems. At the same time, it reduces the residual dust content by half and energy consumption by one third.
Moulds distributed throughout the hall
The main problem was that there is no permanent place in the workshop for casting from which exhaust fumes could be extracted. The huge moulds are distributed throughout the hall, with the exhaust air collecting under the roof. Whenever a skylight is opened, the vapours escape.
The system developed by Kappa will, in the future, collect the exhaust gases directly beneath the hall roof. For this purpose, 17 extraction points have been set up, which circulate a total of 180,000 cubic metres of air per hour. Sensors detect where in the hall casting is being performed, and performance is automatically optimized in the required places.
The emission-loaded hall air is replaced by fresh air. It is preheated to the desired temperature, and diffuses draught-free along the hall floor. "Due to this, there are no draughts, and the workstations are provided with pleasant atmospheres for the workers," says Raphael Mülleder, process engineer at Kappa, who co-developed the system. The system continuously supplies the workers with fresh air, meaning windows and doors can remain closed. The supply air is heated via the recovered excess heat from the existing smelting furnace.
Glass elements ensure transparency of the functions
The extracted air is thoroughly cleaned by the Kappa Ekon® filter system. This is a large de-dusting system with large glass elements made of highly resistant and solid safety glass located at all access areas. Thus, there is a clear view of the well-lit clean gas chamber, which is also easily accessible for maintenance purposes. The cleanliness level of the clean gas can be monitored at any time.
An odour-binding reactant is passed into the exhaust stream upstream from the filter system. This ensures the prior binding of odours from the raw gas. The odour binder subsequently forms a stable adsorption and reaction layer for further odour removal on the filter surface. The emission cocktail of smoke, particulate matter and odours is separated in the Kappa Ekon® in a highly efficient manner before the clean exhaust air is passed into the surroundings.
- The expansion of operations was permitted thanks to the innovative environmental technology.
- The fine dust values in the exhaust air flow are more than tenfold lower.
- The odour emissions fall below the limit values.
- The system's excellent energy efficiency reduces energy consumption by around 32 percent when compared to conventional solutions.