LUEHR FILTER GmbH

The constructive features of the horizontally or vertically installed flat-bag filter elements particularly in combination with the different - off line - cleaning systems included in the range of products allow

• the reliable observance of requested residual particle contents in the clean gas
• exceptionally long filter fabric service lives

at low space requirement and low maintenance Flat-bag filters are used for gas volumes of 1,000 m³/h up to more than 1,000.000 m³/h.

LUEHR FILTER has developed different procedures for the following applications:  

• Chemisorption of acid crude gases such as HF, HCl and SOx with Ca- or Na-based additive powders
• Adsorption of PCDD/ PCDF as well as Hg and Hg-compounds by means of activated carbon/ activated coke or other additives with large internal surface

The sorption procedures applied by us are based on the LUEHR Conditioning Rotor-Recycle Process (KUV) Particularly when using Ca-based additive powders, the realisation of high additive particle recycle rates proved to lead to a definite improvement of the separation efficiency for acid crude gas components such as HF, HCl and SO2 and/ or to a reduction in the additive powder injection quantity. The LUEHR Conditioning Rotor-Recycle Process allows the reliable re-circulation of large recycle quantities even if problematic particles such as CaCl2 form a larger part of the particle spectrum. A widely homogeneous distribution of the re-circulated particles in the flue gas flow will be achieved. Conveyance with pneumatic methods, which is prone to frequent breakdowns, is not used.

Flat-tube heat exchangers are - if necessary - installed upstream of flat-bag filters in order to reduce the temperature of the gases to be cleaned to a temperature admissible for the filter fabric or to adjust the optimum process temperature. During development of this heat exchanger special importance was attached to the objective to achieve a reliable continuous operation, combined with a constant cooling of gases, even in case of high particle loads in the gas and in case of a strongly adhesive character of these particles. Occasional manual cleaning proved to be unnecessary for maintaining the heat transfer.   If necessary we are taking additional measures to ensure a trouble-free continuous operation of the flat-tube heat exchanger and exceptionally long service lives of cooling tubes.  

• Utilisation of a mechanically working cooling area cleaning device in case of presence of particles with adhesive features.
• Avoidance of temperatures below the dew point by using pre-heated cooling air (cooling air re-circulation)
• Avoidance of temperatures below the acid dew point by means of injection of additive powders in the flue gas flow upstream heat exchanger

On request there are different possibilities of heat recovery available, e.g. in form of hot water generation.