Sorption Enhanced Chemical Looping Reforming Of Ethanol

Hydrogen is an important raw material in the oil and chemical industries,used extensively for the production of ammonia,methanol and used as raw material in various petroleum hydrotreating processes.The hydrogen is used on a large scale into the production of the ammonia because hydrogen act as the reactant for the production of the ammonia with the nitrogen Most of the energy we use today is obtained from non-renewable fossil fuels.This has not only depleted the reserves of fossil fuels,especially crude oil,but has also caused severe environmental pollution.Intense research efforts are being made to develop alternative renewable energy sources.The conventional methods of hydrogen production are based on reforming of the natural gas or naphtha.Among the different feedstocks available,alcohols are very promising candidates because these are easily decomposed in the presence of water and generate hydrogen-rich mixture at a relatively lower temperature.The light alcohol ethanol is an important candidate as a chemical carrier of hydrogen,the production of which is useful in a range of fuel cell applications.Not only,is it less hazardous than methanol but it can be produced from a variety of biomass sources.Bioethanol is produced by the fermentation of sugar cane,corn grains,and other starch-rich materials,and is considered to be a mature technology.Recent research has focused on producing bioethanol from lignocellulosic biomass,the so-called second-generation bioethanol.Bio-ethanol to hydrogen system has the significant advantage of being nearly CO₂ neutral,since the produced carbon dioxide is consumed for biomass growth,thus offering a nearly closed carbon loop and does not contribute to greenhouse gas emissions.Steam reforming（SR）is a process technology in which the fuel（hydrocarbon or alcohol）is oxidized by steam,usually in the presence of a catalyst,to produce synthesis gas contains H₂,carbon monoxide（CO）,CO₂,methane CH₄ and steam The chemical looping reforming process used to utilize air as the oxygen carrier.Sorption enhanced chemical looping reforming is a novel technique for the production of hydrogen from the ethanol.The steam reforming involves the endothermic conversion of the fuel,which mean that this reaction occurs at higher temperature.So it demands external heat to maintain the process temperature,which is usually provided by combustion of supplemental fuel that is fed to the furnace.The steam reforming process is a catalytic process,and the catalyst development is considered the heart of sustainable hydrogen production through the steam reforming process In industrial SR process,the Ni catalyst is supposed to permute reforming process for continuous operation before its replacement With the increase in Ni metal loading,the active surface area of the catalyst also increases.The SECLR process used for ethanol reforming with Ni O,as an oxygen carrier,and Ca O used as a CO₂ sorbent.Two interconnected fluidized reactors are used,one as reforming reactor and regeneration reactorThermodynamic analysis examine the effects of the operating parameters on the sorption enhanced chemical looping reforming of ethanol under steady-state condition.The effects of the nickel oxide to steam molar ratio（Ni O/S）,calcium oxide to ethanol molar ratio（Ca O/C₂）,the temperature and the pressure on the performance of the reformer reactor of SECLR process are analyzed in terms of hydrogen production and purity.The optimum conditions of the SECLR process include carbon to ethanol（C/C₂）molar ratio of 0.06,Ni O/C₂ of 0.145,Ca O/C₂ of 7 and S/C₂ of 6.Under these conditions,the H₂ production yield of 5.172 moles per mole of ethanol can be produced on a dry basis with 99.46%H₂ purity.The SECLR process of ethanol enhances H₂ yield and purity due to the combination of both chemical looping reforming and sorption enhanced steam reforming processes.