Production of Fuel Gas through the Hydrothermal Gasification of Wastewater Using Highly Active Carbon-Base Catalyst
Production of Fuel Gas through the Hydrothermal Gasification of Wastewater Using Highly Active Carbon-Base Catalyst
复制标题
DOI：
10.1252/jcej.07we155
复制
发表时间：
2007-12
影响因子：
0.8
通讯作者：
H. Nakagawa;Akio Namba;A. Sharma;K. Miura
中科院分区：
文献类型：
--
作者：
H. Nakagawa;Akio Namba;A. Sharma;K. Miura
含有低浓度的各种有机化合物的废水的处理在世界其他地方引起严重的问题，因此，期望开发用于处理废水的有效方法。在这项研究中，我们开发了一种新型的镍负载碳催化剂用于气化溶解在工业废水中的有机化合物在水热条件下。有机化合物在高于275°C的条件下几乎完全气化。主要气体产物为CH 4、H2和CO2，具有约20 MJ/m3的较低热值，表明产物气体可用作燃料气体。在300°C下气化时，在5 MPa下气化产物主要为H2和CO2，在20 MPa下气化产物主要为CH 4和CO2。反应平衡计算表明，这些结果反映了反应器中水的状态，蒸汽或液体。对所提出的方法的质量和能量平衡的简单计算表明，在Tg = 350°C、P = 20 MPa的条件下，即使当该方法作为独立的方法操作时，也可以回收46%的低热值有机化合物（浓度为3.33wt%的异丙醇水溶液）作为燃料气。这一结果表明，如果满足一定的条件，所提出的工艺不仅可以是废水处理工艺，而且可以是能源生产工艺。
Treatments of wastewaters containing various organic compounds in small concentrations are causing serious problems elsewhere in the world, therefore, the development of efficient process for treating wastewaters has been desired. In this study a novel Ni-supported carbon catalyst that we developed was used for gasifying the organic compounds dissolving in an industrial wastewater under hydrothermal conditions. The organic compounds were almost completely gasified above 275°C under the conditions examined. Main gaseous products were CH4, H2, and CO2, having the lower heating value of around 20 MJ/m3, indicating that the product gas can be used as fuel gas. The product gas composition was highly dependent on pressure: H2 and CO2 were dominant components under 5 MPa, and CH4 and CO2 were dominant ones under 20 MPa when the wastewater was gasified at 300°C. Equilibrium calculation for the reactions clarified that these results reflected the state of water, vapor or liquid, in the reactor. A simple calculation for mass and energy balance of the proposed process showed that 46% of the lower heating value of the organic compound (aqueous isopropyl alcohol solution of 3.33 wt% in concentration) can be recovered as fuel gas under the conditions of Tg = 350°C, P = 20 MPa even when this process is operated as a stand-alone one. This result shows that the proposed process can be not only a wastewater treatment process but an energy production process if certain conditions were met.