Nitrogen transformation during gasification of livestock compost over transition metal and Ca-based catalysts

作者：Cao, Jing-Pei^*; Huang, Xin; Zhao, Xiao-Yan; Wei, Xian-Yong; Takarada, Takayuki

来源：Fuel, 2015, 140: 477-483.

DOI：10.1016/j.fuel.2014.10.008

• Pig compost
• Gasification
• Nitrogen transformation
• Transition metal
• Ca-based catalyst

Catalytic gasification of a pig compost (PC) was investigated over transition metal catalysts (TMCs, including limonite, CoMo/Al2O3, Ni/Al2O3, and nickel loaded on lignite char) and Ca-based catalysts (dolomite and CaO) in a two-stage fixed-bed reactor to understand the effects of catalyst, temperature, and steam on nitrogen distributions. Non-catalytic thermal decomposition (TD) of PC volatiles below 750 degrees C is not effective for decomposing the entire volatile nitrogen species (VNSs) to N-2. NH3 was found to be the predominant nitrogenous gas under inert conditions used in this investigation, and its yield increased with raising TD temperature. The N yield in HCN is lower than 5% below 550 degrees C, and sharply increased to 13.9% at 750 degrees C due to TD of volatiles. Most of VNSs were converted to N-2 over TMCs, especially over Ni-based ones. The TMCs proved to be quite active not only for tar reduction, but also for VNSs decomposition at 450-650 degrees C. On the contrary, CaO-based catalysts, especially dolomite, significantly promoted the conversion of VNSs to NH3. Ni/Al2O3 effectively promoted the conversion of NH3 and HCN to N-2 at 550 degrees C. Steam introduced mainly prevented HCN decomposition over dolomite and coke deposition over Ni/Al2O3. This study provides a basic insight into the nitrogen transformations during catalytic gasification of PC, which would benefit the clean utilization of PC as an energy source.

• 出版日期2015-1-15
• 单位中国矿业大学（北京）