The simultaneous removal of hydrogen sulfide and ammonia over zinc-based dry sorbent supported on alumina

• Published in: Separation and purification technology 2008-10, Vol.63 (2), p.297-302
• Main Authors: Jung, Suk Yong, Lee, Soo Jae, Park, Jung Je, Lee, Soo Chool, Jun, Hee Kwon, Lee, Tae Jin, Ryu, Chong Kul, Kim, Jae Chang
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical engineering; Desulfurization; Exact sciences and technology; NH 3 decomposition; Reactors; Simultaneous removal; Zn–Al-based sorbent
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2008.05.013

To remove H 2S and NH 3 simultaneously from coal-based synthesis gas, Zn–Al-based sorbents promoted with transition metals such as cobalt, nickel and iron additives were prepared by the co-precipitation method. The decomposition of NH 3 and the absorption capacities of H 2S of the sorbents were studied in a micro-reactor at 1 atm and 650 °C. The additives, cobalt, nickel and iron, were found to be active components in the NH 3 decomposition reaction as well as in the absorption of H 2S, while the major components, ZnO and Al 2O 3, did not show any activity in the NH 3 decomposition reaction. Especially, cobalt oxide showed excellent NH 3 decomposition ability, regardless of the H 2 concentration, while the ability of iron and nickel oxides depended on the H 2 concentration. After the oxides were converted to the sulfide form, the NH 3 decomposition rates over the cobalt and nickel sulfides were dramatically decreased in the presence of excess H 2. Optimized Zn–Al-based sorbent promoted with cobalt oxide was prepared and showed excellent NH 3 decomposition ability under a gas composition of 11% H 2, 1% H 2S and 0.5% NH 3, which was due to the improvement of its physical properties such as its surface area, pore size and pore volume, and nano-particle size.