Pilot-scale study on the acid-catalyzed steam explosion of rice straw using a continuous pretreatment system

► A pilot-scale continuous pretreatment system was successfully developed. ► The pretreatment system shows good operational stability and durability. ► 73% of the total saccharification yield was obtained. ► The system can be used for the production of bioethanol and bio-based chemicals. ► The total sugar yield of rice straw in different scale system was compared. A continuous acid-catalyzed steam explosion pretreatment process and system to produce cellulosic ethanol was developed at the pilot-scale. The effects of the following parameters on the pretreatment efficiency of rice straw feedstocks were investigated: the acid concentration, the reaction temperature, the residence time, the feedstock size, the explosion pressure and the screw speed. The optimal presteaming horizontal reactor conditions for the pretreatment process are as follows: 1.7rpm and 100–110°C with an acid concentration of 1.3% (w/w). An acid-catalyzed steam explosion is then performed in the vertical reactor at 185°C for 2min. Approximately 73% of the total saccharification yield was obtained after the rice straw was pretreated under optimal conditions and subsequent enzymatic hydrolysis at a combined severity factor of 0.4–0.7. Moreover, good long-term stability and durability of the pretreatment system under continuous operation was observed.