Regenerative catalytic oxidation

 Synonyms, abbreviations and/or process names

—  Regenerative afterburning

Removed components

—  VOC’s, odour
—  Carbon monoxide
—  Halogenated compounds (specific catalysts required)
—  CO
—  (Fine organic particles)

Diagram

Process description

This is a combination of catalytic afterburning  and a regenerative heat recuperation system. The workings of heat recuperation have been explained in regenerative thermal oxidation.

The yield for heat recuperation can be as high as 98 %, as in regeneration with non-catalytic afterburning. In recuperative catalytic afterburing, autothermic combustion is possible from 1 -2 g/m³ of solvent [5]. According to BAT [7,9] autothermicity is realised from 0.5 -1.5 g/m³.

Variants 

See regenerative thermal oxidation and catalytic oxidation

Efficiency

—  Hydrocarbons:      90 – 99 %. The lower yields are realised with low input concentrations. If one works with 2 beds,
      then one also has a lower yield [2]
—  CO:                          > 98 % [2]

Boundary conditions

See regenerative thermal oxidation and catalytic oxidation

—  In the interest of safety, the hydrocarbon concentration in the flue gas mix must be kept below 25% of the lowest
      explosion limit (LEL).
—  Dust concentrations less than 3 mg/m³ [5].

Auxiliary materials

Only extra fuel needed. The amount required is much lower than a set-up with afterburning.

Environmental aspects

See technique sheet 35

Energy use

Determined by gas composition. Low energy use compared to situation without heat recuperation. Autothermicity is realised from 0.5 -1.5 g/m³ [7,9].

Cost aspects

  • Investment
    —  24 000 -89 000 USD for 1 000 Nm³/h [2]
    —  30 000 – 40 000 EUR for 1 000 Nm³/h [1, 7]
  • Operating costs
    —  Personnel costs:    2 days per year [1]
    —   Operating costs:   3 600 to 12 000 USD per year for 1 000 Nm³/h [2]

Total cost aspects per ton of solvent amounts to 150 – 26 000 USD/ton per year [2]

Major cost factors

—  Flow rate: Size of installation
—  Energy content of gases: Higher energy content means less extra fuel
—  Required removal efficiency determines the residence time. Higher efficiency means higher costs
—  Type of catalyst
—  Measurement and configuration equipment

  • Examples

Case study: Glue spraying booths [6]

—  Flow rate: 10 000 m³/h
—  Load: 1 270 mg C/Nm³
—  16 hours per day operation
—  Investment costs: 307 000 EUR excl. VAT

Case study: flexographic printing [6]:

—  Flow rate: 13 000 m³/h
—  Investment costs: 340 000 EUR excl. VAT 

 

Advantages and disadvantages

  • Advantages
    —  See catalytic oxidation
    —  No corrosion problems with heat exchanger
    —  Homogenisation of gas stream in the bed
    —  Extensive energy recuperation:
    —  Relatively low operating costs
  • Disadvantages
    — 
    See catalytic oxidation
    —  High investment costs
    —  Ceramic beds may become blocked
    —  In discontinuous operation, the bed must be re-heated every time
    —  Large size and weight
    —  A lot of maintenance and moving parts

Applications

In most cases, a thermal regenerative system is installed instead of a catalytic system because thermal yield is very high. A catalytic system is relatively expensive.

Applications are more-or-less the same as thermal regenerative afterburning , on the condition that no catalyst poisons are present.

References

  1. BREF: "Common waste water and waste gas treatment /management systems in the chemical sector" EIPPC, February 2002
  2. EPA Air Pollution Technical factsheet: “Regenerative incinerator”
  3. Factsheets on Air-emission reduction techniques, www.infomil.nl, Infomil
  4. EPA Air Pollution Technical factsheet: “Catalytic incinerator”
  5. VDI 2587 part 1: “Emission control: heatset web offset presses”, November 2001
  6. Supplier information
  7. A. Jacobs, B. Gielen, I. Van Tomme, Ch. De Roock and R. Dijkmans., “Best Available Techniques for the wood processing industry”, October 2003
  8. T Feyaerts, D. Huybrechts and R. Dijkmans., “Best Available techniques for manure processing, edition 2”, October 2002
  9. L. Goovaerts, M. De Bonte, P. Vercaemst and R. Dijkmans., “Best Available Techniques for the metal processing industry”, December 2003
  10. A. Derden, J. Schrijvers, M. Suijkerbuijk, A. Van de Meulebroecke1, P. Vercaemst and R. Dijkmans., “Best Available Techniques for the slaughterhouse sector”, June 2003