(97d) Syngas/ Hydrogen Production Via Gasification of Meat and Bone Meal

Meat and bone meal is a by product of rendering industries. This material is responsible for the transmission of bovine spongiform encephalopathy (BSE) in animals and therefore, it is no longer used as a feed for animals. There are various methods for disposal of meat and bone meal such as land filling, incineration, combustion and gasification. Gasification seems to be promising option out of all. High temperature gasification reaction destroys the potential BSE pathogens and produces gases which can be used either to generate electricity or various chemicals by Fischer-Tropsch synthesis. Gasification of meat and bone meal followed by thermal cracking of tar was carried out using two-stage fixed bed reaction system in series. The first stage was used for the gasification and the second stage was used for thermal cracking of tar. In present work, the effects of temperature (650 °C ? 850 °C) in each stage, equivalence ratio (actual O₂ supply/stoichiometric O₂ required for complete combustion) (0.15 ? 0.3) and packed bed (Ottawa sand, avg. particle size: 0.3 mm ? 1.1 mm) height (40 mm ? 100 mm) of second stage on the product (char, tar and gas) distribution and gas (H₂, CO, CO₂, CH₄, C₂H₄, C₂H₆, C₃H₆, C₃H₈) composition were studied. It was observed that two-stage process increased the H₂ production from 7.3 vol. % to 22.3 vol. % (N₂ free) and gas yield from 30.8 wt. % to 54.6 wt. % compared to single stage. Temperature and equivalence ratio had significant effects on the H₂ production, product distribution and gas composition. It was observed that higher gasification (850 °C) and cracking (850°C) reactions temperatures were favorable for higher gas yield of 52.2 wt. % at an optimum value of equivalence ratio of 0.2. Varying the packed bed height of the second stage from 40 mm to 100 mm reduced the tar yield from 18.6 wt. % to 14.2 wt. % and increased the gas yield from 50.6 wt. % to 54.6 wt. %.