Study On Characteristics Of Biomass Catalytic Pyrolysis Process

Biomass pyrolysis, as an important technology of energy transforming, is the primary process of gasification, combustion and liquefaction. Thus, researches based on biomass pyrolysis are of great theoretical and practical value.Thus, the main purpose of this study is to investigate the differences of pyrolysis characteristics among pinewood, peanut shell and straw. And influence of potassium carbonate (K₂CO₃) on the slow pyrolysis behaviors was also researched. All the pyrolysis experiments were carried out in a fixed-bed reactor.It was observed that pinewood lost more weight than the other two during the slow pyrolysis process. However, straw, which wa rich in ash matter and low in volatile matter, turned into more char. The ash matter in straw contained amounts of metal elements, such as K+,Ca2+,Na+and so forth. These metal elements made tar much easier break into small-molecule combustible gases. Thus more H2 could be produced from straw than pinewood and peanut shell.When potassium carbonate (K₂CO₃) was added into biomass by impregnation way, the yields of gaseous products from pinewood, peanut shell and straw were all improved markedly. Among the three biomasses, in the prensence of impregnated K₂CO₃ peanut shell became most efficient H2 supplier. But most of H was still in tar. Tar from the catalytic pyrolysis by potassium carbonate (K₂CO₃) contained less light components. The yields of saccharides, furans, acids and aldehydes were especially reduced. It was very hard to explain why potassium carbonate (K₂CO₃) , which made pinewood and peanut shell easier to produce char, kept straw from turning into char. Generally, K₂CO₃ was very favorable for pinewood, peanut shell and straw's producing qualities-improved gaseous and liquid products.