Study On Technology For The Pretreatment Process Of Continuous Digesting Steam Explosion For Lignocellulose

Making ethanol with lignocellulose to provide energy for the human has become an important approach to study in the world.However,there are some problems at present for the lignocellulose pretreatment technology such as higher cost,more energy consumption and more inhibitor content.They restrict the industrialization of lignocellulose pretreatment technology.The digesting step is combined into the steam explosion pretreatment process.Consequencely,technology in continuous digesting steam explosion pretreatment for lignocellulose is put forward,and equipment for continuous digesting steam explosion pretreatment is developed.The structure parameter and the operation parameter of the equipment for continuous digesting steam explosion pretreatment are comprehensively analyzed.The operation and effect experiment are done for enhancing the effect of the lignocellulose pretreatment technology and promoting its industrialization progress.Digester?steamter and spray explosion device are analyzed by single factor method with Fluent.And they are optimized by orthogonal test.It provides a theoretical basis for design of equipment.The numerical model of digester is set up.The influence of steam temperature,steam flow,water content and screw speed on the highest temperature and average temperature of water mix material,and pretreatment intensity based on the highest temperature and average temperature is studied.The optimal group of digesting process with water content 50%,steam flow 25 kg·h-1,screw speed 0.75 rad·s-1 and steam temperature 180? is acquired with the order in the magnitude of impact.The numerical model of steamer is set up.The influence of steam temperature,the initial temperature of cornstalk,the initial volume fraction of cornstalk and screw speed on the highest temperature and average temperature of cornstalk,and pretreatment intensity based on the highest temperature and average temperature is studied.The optimal group of steamting process with the initial temperature of cornstalk 180?,steam temperature 240 ?,the initial volume fraction of cornstalk 15%and screw speed 0.6 rad·s-1 is gained with the order in the magnitude of impact.The numerical model of spray explosion device is set up.The influence of valve's opening angle,spray explosion tube diameter,spray explosion time and spray explosion pressure on steam consumption,cornstalk production,the ratio of cornstalk and steam and outlet velocity is studied.The optimal group of spray explosion process with valve's opening angle 90°,spray explosion tube diameter DN25,spray explosion time 1.5s and spray explosion pressure 1.5MPa is obtained with the order in the magnitude of impact.Equipment for continuous digesting steam explosion pretreatment is developed according to the results of analysis and optimization.Equipment operation experiment is down for digester,steamer and spray explosion device.Consequencely,the result of numerical calculation is similar with the actual situation.It has better reference value for developing continuous digesting steam explosion equipment.The effect experiment of continuous digesting steam explosion pretreatment for cornstalk is down based on the equipment for continuous digesting steam explosion pretreatment.The results show that some inhibitors are removed.And enzymatic hydrolysis effect of steam explosion product effect is better.Less amount of enzyme is used when glucose yield reaches 80%.Treatment effect of the technology is recognized.A better kind of lignocellulose pretreatment technology with less inhibitor content is provided,namely technology for continuous digesting steam explosion pretreatment.And a set of equipment for continuous digesting steam explosion pretreatment is developed based on the relevant technology.It contributs to the study schedule of lignocellulose pretreatment technology with better effect.It also promote the industrialization process of comprehensive utilization of lignocellulose.And it is conducive to the sustainable development of energy.