Cellulose Dilute Acid Hydrolysis Saccharification Process

Lignocellulosic materials are the most abundant renewable resources in the world. The cellusic biofuel technology is an important way to resolve the current global energy crisis and is potential at present. In this paper the wheat straw was used as material to hydrolyse under the dilute acid with the co-catalyst metal salt ions, which based on summary of cellulose utilization technology.Firstly, the experimental research was carried out to study the effct of acid concentration, temperature and reaction time on conversion ratio and reducing sugars yield to determine the optimum of reaction parameters. Based on this result, the orthogonal experiments were studied with the introduction of the Fe2+, Na+, Ni2+ and Mg2+. The four metal salt ions have played a catalytic role on the hydrolysis of cellulose, in which Fe2+ is the best co-catalyst. It showed that the catalytic ability of the four metal salt ions was Fe2+>Na+>Ni2+> Mg2+. The optimal process was that sulfur acid was 1.0%, Fe2+ was 0.037mol/L, temperature was 180℃and reaction time was 90 min. The yield of reducing sugar reached 73.05%, and the conversion rate of cellulose reached 85.79%.It was studied that the acid hydrolyzate was decolored and detoxified by using of Ca(OH)2 and activated carbon adsorbent. The single factor experiments and orthogonal experiments were used to determine the optimum conditions. It showed that temperature was 35℃, the initial pH was 4.0, the reaction time was 60 min, and the ratio of activated carbonto hydrolysis solution (g/L)=1:2. Under these conditions, the decolorization rate of activated carbon reached 88.11%, the removal rate of furfural was 74.91%, and all the pholic compounds were removed completely.Based on the review of biomass hydrolysis model, the experimental data which straw was hydrolysed catalysed with Fe2+ and 1.5% sulfur acid were simulated by heterogeneous and pseudo-homogeneous consecutive first-order reactions model respectively. The kinetic model can be written as: The result was well agreed with the experimental data.