Co-production Of Activated Carbon And Bio-oil From Agricultural And Forestry Residues

Biomass is the fourth largest primary energy, which is the onlyrenewable energy that could be stored and transported. Agricultural andforestry wastes （crop straw, rice husk and sawdust, etc.）, the focus ofbiomass energy utilization, account for2/3of the total biomass resources.In this paper, a pilot study by using agricultural and forestry waste togenerate bio-oil and biochar is carried out, where molten salt adopted asthe heat carrier, the catalyst and the dispersing agent.Biomass materials were characterized by elemental analysis,proximate analysis and chemical quantitative analysis of the maincomponent. The pilot study was investigated in the man-made reactor.The influence of the composition of the molten salt, pyrolysistemperature, inert gas flow, the types of raw materials, the raw material’sparticle size and the pretreatment methods of raw materials and otherfactors on the molten salt pyrolysis of biomass was observed. Gaseous products and liquid products were analysed by gas chromatography （GC）and GC-MS spectrometer （GC-MS） individually and solid products wereactivated by ZnCl₂. The results show that: Add molten salt cansignificantly improve the yield of solid products and liquid products inpyrolysis of biomass, and improve the selectivity of the gaseous productsof H₂and CH₄;The pyrolysis conditions affect the products yield and theircomposition distribution; The pyrolysis temperature was too high, thesecond cleavage reaction intensified, the pyrolysis temperature was toolow, the pyrolysis was incomplete; The low inert gas flow, the secondarycracking of biomass; The raw material particle size of biomass was lessaffected the pyrolysis product yield and composition distribution; Frompyrolysis of rice straw after pickling and washing in molten salt, the solidproducts and liquid products were reduced, and the gaseous productswere increased; As the pyrolysis temperature Increased, the preparation ofactivated carbon yield little change, but the iodine adsorption value andmethylene blue adsorption values were significantly reduced; Activationconditions has a great influence on the yield and adsorption properties ofactivated carbon; ZnCl₂plays a very apparent activated role; The surfacearea of activated carbon made by rice straw which pretreated by10%H₂SO4was2451.2m²·g^-1; The test verified the feasibility ofsemi-continuous to produce activated carbon.On the basis of the pilot study, the process line of using agricultural and forestry wastes to generate bio-oil and bio-char was put forward,which provides a basis for the industrial production.