No abstract

Difficulties in the production of lignin from rice straw because of high silica content in the recovered lignin reduce its recovery yield and applications as bio-fuel and aromatic chemicals. Therefore, the objective of this study is to develop a novel method to reduce the silica content in lignin from rice straw more effectively and selectively. The method is established by monitoring the precipitation behavior as well as the chemical structure of precipitate by single-stage acidification at different pH values of black liquor collected from the alkaline treatment of rice straw. The result illustrates the significant influence of pH on the physical and chemical properties of the precipitate and the supernatant. The simple two-step acidification of the black liquor at pilot-scale by sulfuric acid 20w/v% is applied to recover lignin at pH 9 and pH 3 and gives a percentage of silica removal as high as 94.38%. Following the developed process, the high-quality lignin could be produced from abundant rice straw at the industrial-scale.

This work is to implement a working model of an integrated process for bioethanol in the process simulation based on rigorous model using the Aspen HYSYS simulation software. As a case study, the simulation is applied to design a pilot plant that converts rice straw into ethanol. The model is based on the process for biochemical conversion of lignocellulosic biomass (rice straw) to ethanol, proposed by the pilot plant of producing bio-ethanol with capacity of 152 kg rice straw/batch. The plant for manufacturing bio-ethanol with rice straw as raw materials comprises basically three units: Pretreatment of rice straw by alkaline treatment; Simultaneous saccharification fermentation (SSF) of rice straw to produce bio-ethanol and the unit for separation and purification of bio-ethanol mixture from simultaneous and fermentation unit. Modeling of rice straw feedstock as a solid material in Aspen HYSYS, including the creation of necessary hypothetical components. Investigate and analyze the final ethanol yield of the simulation project in comparison with actual process. The model proposed was for easily evaluate and analyze various factors which affect to the final ethanol yield by changing operating conditions and being possible to find the optimal conditions for different input flow rate and many independent factors. The simulation model obtained in this study can be applied to any SSF processes with different biomass feedstock.