Hydrogen Production From Sorption-enhanced Steam Reforming Of Lignin And Its Derivatives

As a source of a wide range of biomass resources,lignin can be used not only in the biomedical field,but also in the production of downstream aromatic chemicals.Because of the complex structure of lignin,the physical and chemical properties vary greatly with its sources leading to great challenges in industrial application.With the increasing energy crisis and environmental problems,exploring efficient utilization of lignin resources can not only reduce the dependence on fossil fuels,but also reduce greenhouse gas emissions.The adsorption-enhanced steam reforming process of lignin resources produces hydrogen as a clean energy,meanwhile in situ captures CO₂.In this work,Ni-Ca-Al-O bifunctional catalysts were used to study the performance for adsorption-enhanced steam reforming of lignin and its derivatives.Using phenol as a model compound,the 5Ni-CA2.8 catalyst showed good catalytic performance and adsorption stability at a reaction temperature of 550°C for its adsorption-enhanced steam reforming.The concentration of hydrogen can reach up to 98%,and the phenol is almost completely converted.At the same time,after 10 cycles of adsorption and desorption cycles,the adsorption capacity of the catalyst was maintained at 71%of the initial capacity.In a micro-reactor and a scale-up reactor,the 5Ni-CA2.8 catalyst both exhibited good stability.The concentration of hydrogen can be maintained above 98%during 50 reaction-calcination cycles.Furthermore,we demonstrated that 10Ni-CA2.8 catalyst showed good catalytic performance in the adsorption-enhanced steam reforming of black liquor.However,the catalytic performance was not further improved after doping with noble metal.At 550°C,S/C ratio of9.89 and gas hourly space velocity of 4490 h^-1,the concentration of hydrogen reached 97%and the yield of hydrogen was 1.01 mol H₂/mol C.Due to the complicated composition of black liquor,the catalyst suffered from a certain deactivation due to the carbon deposition and formation of calcium sulfate after 8 reaction-calcination cycles,resulting in the decreasing of hydrogen concentration.