Reforming of tars and hydrocarbons from gasified biomass

• Tars are produced during gasification of biomass due to thermal decomposition of main constituent of the biomass, cellulose, hemicellulose and lignin. Since the tars will condense on colder surfaces, they cause problems by clogging of pipes and valves and depositions on heat transfer surfaces, for instance. One strategy is to remove the tars by condensing them in water or oil scrubbers, however since the tars might contain a significant part of the heating value in the producer gas the yield of the produced synthesis gas will decrease. To utilize the heat content in the tars they can be converted in situ to synthesis gas either by a catalytic process like steam reforming or autothermal reforming (ATR). The problem with catalytic reforming is that the catalysts used are sensitive towards the sulphur content, mainly H2S, in the producer gas. The deactivation of the reforming catalysts can be counteracted by increasing the reforming temperature, for instance  by the use of ATR. However, at elevated temperature, 1000-1100 oC, the thermal sintering of the catalyst will be accelerated instead. There is a need for development of new high temperature stable reforming catalysts. Another problem is the production of soot due to the high temperatures in the flame in the autothermal reformer unit. The formed sooth will cause problems by clogging packed bed of reforming catalyst and to cope with this it is probably necessary to use a monolithic catalyst.   However, by developing a way to homogenous combust the added oxygen, avoiding the peak temperatures in the flame, would suppress or eventually eliminate the soot formation.      

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

Bioenergy Technology

Bioenergiteknik/Energi- och Miljöteknik

Publikations- och innehållstyp

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