Study On Catalytic Conversion Of Biomass To Hydroxyacetone And Its Separation

Catalytic pyrolysis is a high conversion efficiency of biomass thermal chemical conversion technology,which can selectively converted into different bio-based chemicals.Biomass catalytic pyrolysis of bio-oil produced in a variety of chemicals,such as the hydroxyl acetone,furfural,acetic acid,etc.Hydroxy acetone as an important drug intermediate,is a significant component of high value added in the water phase of pyrolysis liquid.If the hydroxyl acetone can be separated from the water phase,it is possible to obtain good economic and environmental benefits.For the existing the water phase of pyrolysis liquid?so called wood vinegar?,it is desired to separate sequentially through de-phenol extraction and ion exchange resin adsorption,hydroxyl acetone and acetic acid were isolated..MCM-41 was modified by mixing metal atom into the silica framework and changing synthesis conditions.In order to choose suitable catalyst,the structure and properties of modified MCM-41 were studied by XRD and BET,then its influence on cellulose pyrolysis was analyzed by using PY-GC-MS.The main conclusions are as follows:The metal modified M-MCM-41?M=Cu,Ti,Ti/Zn?mesoporous molecular sieves were synthesized by hydrothermal method.The experimental results show that the crystal grain,specific surface area,average pore size and average pore volume of MCM-41 mesoporous molecular sieve are decreased by the modification of metal,and the structure of M-MCM-41 mesoporous molecular sieve is optimal when the Si/M mole ratio is 50.The selective catalytic activity of MCM-41 mesoporous molecular sieves was improved by metal modification,and the optimum value was increased with the increase of the proportion of metals.The content of aldehyde and ketone in the pyrolysis products of cellulose was increased by M-MCM-41 mesoporous molecular sieve,and the content of dehydrated sugar decreased.But the target product?hydroxyl acetone?of cellulose pyrolysis showed a little selectivity,the selectivity order wasTi-MCM-41>Ti/Zn-MCM-41>Cu-MCM-41.The ratios of M-MCM-41 were: n_Si:n_Ti=40:1?Ti-MCM-41?,n_Si:n_Zn:n_Ti=100:1:5?Ti/Zn-MCM-41?,Cu-MCM-41(n_Si:n_Ti=10:1).Then the paper using de-phenol method,through solvent selection,optimization of extraction conditions to determine the optimum extraction conditions,the results showed that using the phenol extractant from self-made,optimum extraction ration was 1.5,the best extraction times was 3,the phenol removal rate was 69.86%.The self-made extraction agent can be used for recovery and regeneration,and can be used for many times to remove the phenol in wood vinegar,which can greatly reduce the actual production cost.And study of the absorption of resin on de-phenol solution,the adsorption effect between 5ion exchange resins?D201,D301,D301 R,D370,D380?,dynamic adsorption and dynamic desorption experiment using static adsorption,and found that D301 R has the best effect.Thehe method of stepwise elution of acetic acid and hydroxy acetone was adopted.Sodium carbonate solution and anhydrous ethanol as the elution agent of acetic acid and hydroxy acetone.Finally,the desorption rate of acetic acid reached 80%,and the resolution ratio of hydroxy acetone reached 90%.In the end,hydroxy acetone accounted for 65.3% of the total amount of organic phase in enriched wood vinegar.