Liquefaction Of Paper-aluminum-plastic Complex Material To Bio-oils In Sub-/supercritical Water

Paper-aluminum-plastic complex packaging waste has seriously threatened the urban ecological environment in China.The supercritical hydrothermal liquefaction teclhnology provides a new way for the energy conversion of this waste to bio-oil,for its fast and high efficiency advantages.This paper uses sub-/supercritical water(SCW)liquefaction convert waste and biomass to bio-oil to improve the value of the recycled products of waste Tetra Pak.First,liquefaction performances of waste Tetra Pak in SCW were evaluated in micro-batch reactors.The influences of temperature(300-420 ?),pressure(16-24 MPa),residence time(5-60 min)and feed concentration(5-40 wt%)on bio-oil were investigated.Then,according to the component ratio of paper:aluminum:plastic in real Tetra Pak,the variation of liquefaction performance of the single-,double-and triple-component model samples and the interaction between different components in Tetra Pak were investigated,and the possible liquefaction pathways of Tetra Pak were also proposed.Finally,the bimetallic supported catalyst Ni-Cu/y-Al2O3 was added further reduce the liquefaction temperature and improve the quality of bio-oil.The Ni fixed loading was fixed as 10 wt%,and the ratio of Ni:Cu was set as 10:1-10:7.The influence of Ni-Cu/y-Al203 on the liquefaction of waste Tetra Pak in SCW was investigated.The results showed that bio-oil yield increased first and then decreased with temperature,reaction time,pressure and feed concentration.Maximum bio-oil yield with 35.55 wt%obtained at 360 ?22 MPa,30 min and the feed concentration of 20 wt%.Temperature had an positive effect on high heating value(HH V),and maximum HHV with 48.747 MJ/kg was obtained at 420 ?,20 MPa,30 min and feed concentration of 20 wt%.There was a synergistic relationship between paperboard and low density polyethylene(LDPE)in Tetra Pak.In addition,aluminum foil also played a catalytic role in liquefaction process.The bio-oil derived from triple-component model sample"paperboard+LDPE+Al" had maximum bio-oil yield of 19 wt%and maximum HHV of 30.037 MJ/kg,respectively.When Ni loading was fixed as 10 wt%,bio-oil yield increased first and then decreased slightly with the increase of Cu loading.Macimum bio-oil yield of 26.64 wt%was obtained at Ni:Cu-10:5.The addition of Cu could promote the ring opening and hydrogenation reaction in bio-oil,and it is beneficial to inhibit the carbon deposit of catalyst surface and reduce the loss of the catalyst BET during liquefaction process.This study is expected to provide a new method for the production of low-oxygen bio-oil from liquefaction of paper-aluminum-plastic complex packaging waste.