Nanomaterial Solutions for Hot Coal Gas Cleanup

Integrated gasification combined cycle (IGCC) is a new coal gasification technique that efficiently uses the hot (900-1500°C) generated syngas to power both steam and gas turbines. Due to regulations, this syngas must be free of sulfur and purification is normally carried out at reduced temperatures (< 500°C); however, using this temperature requires the cooling and reheating of coal gas, which is energy inefficient. It is, therefore, desirable to develop hot gas (900-1500°C) desulfurization and ammonia removal techniques. Classic zinc oxide sorbents are effective at H2S removal, but do not function at these high temperatures because the zinc metal formed in the reducing atmosphere can easily vaporize above 600°C. nGimat proposes to build a prototype regenerable desulfurization and ammonia purification unit using novel oxide nanomaterials. nGimat will use its NanoSpray combustion technology to produce nanopowders and composites with high (20-100 m2/g) surface areas that will show dramatic improvement in sorption/gettering abilities over state-of-the-art materials. The primary advantage of combustion chemical vapor condensation (CCVC)-produced nanopowders over other techniques is that the high synthesis temperature produces a stable nanoparticle with excellent surface area retention at elevated temperatures. This allows for maximized active surface area over longer sorption-regeneration cycle life, yielding purer coal gas without extra cooling and heating in the cycle. Coal power accounts for 50 percent of the electricity in the United States. The current market is $100 to $200 billion per year and has the potential to grow significantly over the next 5 years if a cleaner technology can be realized. Additionally, a clean syngas produced inexpensively and efficiently from coal has the potential to compete with diesel in the automotive arena, should oil prices continue to rise.