Study On Calcium Base Catalytic Gasification Of Biomass For Hydrogen Production

It is a hot issue to get high-purity hydrogen while achieving zero emissions of carbondioxide in the process of hydrogen production. Biomass char and volatiles can be divided inthe process of biomass staging gasification, thus, the mechanism of volatiles reforming andbiomass coke gasification can be investigated well in the process. In this thesis, a staginggasification system was used to study biomass staging catalytic gasification for hydrogenprocuction.The calcinated dolomite, calcinated olivine, calcinated limestone and CaO were firstlyemployed for the steam reforming of volatiles from corn stalk. The results showed thatthese catalytic absorbents are helpful for the hydrogen production of corn stalk volatiles.High yield and concentration of H2were obtained under the effect of calcinated dolomite,followed by those of CaO and calcinated olivine. However, in order to achieve a higherconcentration of H2, the reforming temperature cannot be too high, about650oC will bebetter to ensure a good condition for the carbonation performance of CaO. While thepyrolysis temperature has little influence on the components of gas product, but it is helpfulfor the H2yield. The yield and concentration of H2will be influenced by many factors,including the intense of steam, kinds of catalysts, types of biomass, and the ratio of biomassto steam.It was found that the H2yield has a large gap between the ideal and the experimentalconditions, although the catalysts had been used. Therefore, NiO/CaO catalist was madewith impregnating of high catalitic NiO on CaO and CaCO3. The results showed that CaOof NiO/CaO obtained from impregnation of NiO on CaO has better carbonationperformance than that of NiO/CaO made from NiO impregnated on CaCO3. Besides, theeffect of NiO/γ-Al2O3with different loads (5wt.%,15wt.%, and25wt.%) of NiO has beeninvestigated, and the results presented that NiO/γ-Al2O3can accelerate the steam reformingof corn stalk volatiles, while the best effect was achieved with the medium load of NiO, i.e. 15wt.%.Finally, the influence of CaO and calcinated dolomite on the steam gasification of cornstalk coke, and the effect of corn stalk coke on the steam reforming of corn stalk volatileswere explored. The results showed that CaO and calcinated dolomite can accelerate thesteam gasification of the corn stalk coke, and they have similar effects on the change of gascomponents and yield when the temperature changes, however a higher concentration andyield of H2was obtained with CaO. In addition, higher concentration and yield of H2couldbe achieved with higher temperature. Besides, the corn stalk coke is helpful for the steamreforming of corn stalk volatiles, and under the effect of corn stalk coke, less smallmolecules and more big molecules were obtained in the liquid product.