Measurements of Sulfur Capacity Proportional to Zinc Sulfidation on Sorbent Containing Zinc Ferrite−Silica Composite Powder in Pressurized Coal Gas

• Published in: Industrial & engineering chemistry research 2002-06, Vol.41 (12), p.2903-2909
• Main Authors: Kobayashi, Makoto, Shirai, Hiromi, Nunokawa, Makoto
• Format: Article
• Language: English
• Subjects: Air pollution caused by fuel industries; Applied sciences; Atmospheric pollution; Combustion and energy production; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Pollution; Pollution reduction; Prevention and purification methods; Stack gas and industrial effluent processing
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie010846r

Zinc ferrite−silica composite powder was subjected to a series of reduction and sulfidation tests performed at mainly 450 °C in a simulated coal gas environment. In situ X-ray diffraction analyses revealed that ZnS and FeS were produced at a H2S concentration of 1 vol %, whereas only zinc sulfides were detected at 80 ppm. The scheme for sulfidation at 450 °C was essentially the same as that of pure zinc ferrite at 550 °C. The desulfurization sorbent containing the composite powder was subjected to pressurized thermobalance to determine the sulfur capacities of zinc and iron separately by applying high and low H2S concentrations for sulfidation. This method was applied to analyze the change of the zinc-related sulfur capacity of sorbent samples that experienced multiple desulfurization cycles up to 20 times. At the end of the cycles, the zinc-related sulfur capacity had fallen to about 50% of its initial value, whereas the sulfur capacity due to iron sulfidation maintained 91% of its initial value. This indicates that the residual sulfur mainly results from the production of zinc sulfate during multiple desulfurization cycles.