Power generation from biomass

Syngas production for NOx reduction

Recent studies, including those at Boreskov Institute of Catalysis (BIC), proved a mixture of hydrogen and carbon monoxide (synthesis gas) to be an efficient NOx reducer as well. The synthesis gas can be produced by the reactions of steam reforming, autothermal reforming or partial oxidation of upgrading pyrolysis oils. Unfortunately, no information on respective catalysts or catalytic systems is available from literature that may be attributed to the task novelty and complex character of the studied systems.

BIC’s analysis of the present state of art is based on the assumption that, regarding properties and performance, upgrading pyrolysis oils can be imitated by a model mixture of two fuels – diesel and aqueous ethanol. For autothermal reforming of this mixture activity of the studied catalyst decreases in the following order: Ru, Rh > Ir > Ni, Pt, Pd. The cheapest nickel-based catalysts are used most often. To diminish coking, the Ni-based catalysts are doped with alkaline-earth metal oxides, titanium oxide and lanthanum. Nevertheless, operation life of existing catalysts for heavy hydrocarbons reforming does not exceed several hundred hours.

High demand for the catalysts for the reforming of upgrading pyrolysis oils to synthesis gas to be applied in energy-efficient engines and power generating systems dictates new requirements for the catalyst performance and properties, namely: high thermal and coking resistance; thermal conductivity; matching of thermal-expansion coefficients of catalytically active layer and support; reliable adhesion of the catalyst layer to metal support surface; possibility to use catalysts as the reactor structural elements.

Earlier BIC studies allow conclusion that structured net-supported catalysts with sufficient axial and radial heat conductivity show clear promises for the development of the catalysts for autothermal reforming of diesel fuel. Lab-scale trials of the above catalysts proved them promising for autothermal reforming of diesel fuel under the following conditions: О2/С = 0.5-0.6, Н2О/C = 1.5-1.7, contact time 0.3-0.3 s, inlet reactor temperature 300-400°C. Respective product distribution was as follows (on dry basis): H2 = 32%, СН4 = 1%, СО2 = 12%, СО = 11%, N2 = 44%.