Feasibility Analysis of Steam Reforming of Biodiesel by-product Glycerol to Make Hydrogen

摘要

Crude glycerol is the major byproduct from biodiesel industry. In general, for every 100 pounds of biodiesel produced, approximately 10 pounds of crude glycerol are produced as a by-product. As the biodiesel industry rapidly expands in the U.S., the market is being flooded with this low quality waste glycerol. Due to its high impurities, it is expensive to purify and use in food, pharmaceutical, and cosmetics industries. Biodiesel producers should seek an alternative method which is economically and environmentally friendly. This research contains reforming process to covert waste glycerol from a biodiesel industry into sellable hydrogen. This process consists of 850oC reformer, 350oC and 210oC shift reactors for water gas shift reaction, flash tanks, and a separator. It is considered to be the least expensive method. At 850oC and 1 atm pressure, glycerol reacts with superheated steam to produce gaseous mixture of hydrogen, carbon dioxide, carbon monoxide, and methane. Reformer is a batch process where only 68% of waste glycerol is converted into gaseous mixture. The excess glycerol is recycled back as a feedstock. Water gas shift (WGS) reaction, further convert carbon monoxide into hydrogen and carbon dioxide which is further subjected to separation process to isolate hydrogen from CO2 and any other impurities. The final product stream consists of 68% of hydrogen, and 27% of CO2 based on molar flow rate.