Hot gas filtration

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In fluid technology, hot gas filtration is understood to be the filtration that takes place at gas temperatures above 260 ° C. There are special requirements for the filter material.

Basics

To increase efficiency in various technical processes, such as As the coal gasification , it may be necessary to dust-containing exhaust gases at temperatures between 350 ° C and 1000 ° C dust . Incrustations and blockages can also be prevented by avoiding condensation and desublimation processes. Even at temperatures above 260 ° C, however, conventional filter media are no longer resistant, so that alternative filter media have to be used. It should also be noted that the viscosity of gases increases with increasing temperature and consequently the pressure loss increases. The permeability of the filter medium can possibly also be temperature-dependent.

The filter media used include metallic materials and high-temperature wool. The use of filter elements made of fiber ceramics is also possible. Furthermore, bulk bed filters can be used by means of suitable bulk material . As a rule, the filter media are used as surface filters that form a filter cake . The filter cake must be removed periodically using suitable fluidic measures. It should be noted that sintering effects or the formation of a eutectic can lead to caking below the respective melting temperature of the dust to be separated.

In addition to coal gasification, hot gas filtration is used in the production of color pigments and calcium carbide . It is also used successfully for waste gas treatment in thermal soil treatment .

literature

  • VDI 3677 Part 3: 2012-11 Filtering separators; Hot gas filtration (filtering separators; high-temperature gas filtration) . Beuth Verlag, Berlin. ( Summary and table of contents online )

Individual evidence

  1. ↑ a b Thomas Hilligardt: Hot gas filtration with filter elements made of fiber ceramics. In: Dust - cleanliness. Air . 50, No. 3, 1990, ISSN  0949-8036 , pp. 107-111.
  2. ↑ Steffen Heidenreich: Hot gas filtration. In: Chemical Engineer Technology . 84, No. 6, 2012, ISSN  0009-286X , pp. 795-807.
  3. ↑ VDI 3677 sheet 3: 2012-11 Filtering separators; Hot gas filtration (filtering separators; high-temperature gas filtration) . Beuth Verlag, Berlin. P. 7.
  4. ↑ a b c VDI 3677 sheet 3: 2012-11 Filtering separators; Hot gas filtration (filtering separators; high-temperature gas filtration) . Beuth Verlag, Berlin. P. 2.
  5. ↑ Harald Hoffmann, Michael Brachthäuser: New kind of packed bed filter for hot gas cleaning. In: Chemical Engineer Technology. 60, No. 1, 1988, ISSN  0009-286X , pp. 36-38.
  6. ↑ VDI 3677 sheet 3: 2012-11 Filtering separators; Hot gas filtration (filtering separators; high-temperature gas filtration) . Beuth Verlag, Berlin. P. 31.
  7. ↑ VDI 3460 sheet 1 : 2014-02 emission reduction; Thermal waste treatment; Basics (Emission control; Thermal waste treatment; Fundamentals) . Beuth Verlag, Berlin. P. 65.