Deactivation of catalysts for fossil coal and biomass conversion

Increasing interest in the use of resources of organic raw materials alternative to petroleum stimulates researchers to study the catalytic intensification of fossil coal and vegetable biomass conversion. The industrial use of the developed technologies is restricted by the problem of enhanced catalyst deactivation. The main reasons for catalyst deactivation in solid organic raw materials conversion are considered in the review. The possible ways of the successful solution of the problem of catalyst deactivation in the processes of coal and biomass liquefaction and gasification and wood delignification and hydrolysis are exemplified by the studies accomplished over the last decade. In the case of technologies using the synthetic catalysts, the methods of their regeneration developed for the catalytic processing of heavy petroleum residues can be applied. The catalyst regeneration is not demanded for the processes accomplished in a fluidized catalytic bed under the conditions of catalyst loss as a result of its attrition and in the case of the application of melted catalysts, cheap iron-containing catalysts, catalytically active slag materials, and natural minerals. The substitution of dissolved catalytic systems for solid catalysts allows for the diminishing of their deactivation in the processes of wood delignification and hydrolysis.