Experimental study of the effect of acid-wash pretreatment on biomass pyrolysis

The influence of acid-washing pretreatment on biomass pyrolysis was experimentally studied in a radiation reactor. The results show that the metal ions content of rice husk treated by acids is reduced markedly. The yield of tar from pyrolysis of rice husk treated by 7% HCl increased from 41.74% to 52.88%, and the yields of gas and char decrease. The influence will be more remarkable with the increase of acid concentration. The gaseous products of pyrolysis of HCl-treated rice husk mainly consist of CO and CO₂ which yields decreased metal ions content when compared with those of the raw sample. The effects of H₂SO₄, HCl, and H3PO4 on biomass pyrolysis are different. HCl has the strongest effect on the pyrolysis products distribution because of the least amounts of K⁺ remained after HCl treatment. The microstructures of biomass are damaged seriously by H₂SO₄ treatment.