The Physicochemical Property Analysis Of Bio-oil And Research On Hydrogen Production By Steam Reforming Of Bio-oil

The heat value of hydrogen is the highest among fuels, it is also a clean energy:generations only water when burning which cannot do harm to the environment. Make use of the Bio-oil by steam reforming of it to get hydrogen is a very promising technology, in this study the steam reforming of bio-oil was investigated.Cornstalk derived pyrolysis bio-oil was analysed by its physics and chemical properties, such as pH, solid, ash, heat value, density and composition in the passage. We fond that its pH at first is4.0, however it turns lower as the time goes on; the solid is0.2-0.6wt%higher than petroleum (<0.5wt%) due to its pyrolysis technology and low carbon residue remove method; ash in the oil is little and its density is1.0kg/dm30.2kg/dm3higher than fuels like petroleum and diesel; the composition is very complex and most of them are acetic acid, acetol, ethanal, furan and so on. The bio-oil is acidity because of the acid mostly acetic acid in the oil. Acetic acid is a more safety hydrogen carrier because it is not explosive compare with methanol and ethanol.So this work took acetic acid as the research object, present the thermodynamic analysis of hydrogen production via steam reforming of acetic acid. The results showed that:the reaction influences a lot by temperature, the productivity of H2grow higher as the temperature increases, however, when temperature above600℃the productivity decreases a little, the best temperature is500℃-700℃to get best productivity and selectivity of H2. The water to carbon rate also influences the reaction, the productivity of H2and CO2increase obviously as the water to carbon rate grows through the increase rate slower when it above6:1; the increase of pressure makes the decrease of productivity and selectivity of H2and increase of the selectivity of CH4.The influences of temperature and the content of nickel in catalyst to produced H2,CO,CO2CH4and their selectivities is studied in the experiment of acetic acid and bio-oil steam reforming on the designed fixed bed reactor. It is found that the total gas amount get in the reaction bio-oil is bigger than that produced by the steam reforming of acetic acid with the same factors. The total amount is similar with other temperature when it is400℃, the hydrogen is45%of the total gas amount. As the temperature increase to500℃,600℃and700℃total gas amount increase and the selectivity of hydrogen grow from60%to75%-95%, at the same time, selectivity of CH4and CO decrease a lot. The increase of nickel in catalyst improves the productivity of H2and decreases the productivity of CO, CO2and CH4. The selectivity of H2also improves as the nickel increase, however, the selectivity of CH4decreased. The activity time of catalyst used in the experiment is180min limited to experiment time.