Process Optimization on Synthetic Natural-Gas (SNG) Production from an IGCC Power Plant

• Main Authors: Wei-Sheng Chang, 張惟盛
• Other Authors: 陳錫仁
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/14200767525053235789

碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 101 === Recently, there is no denying the fact that people like to be eco-friendly, which means being kind to the environment. Therefore, people have started to reduce the use of nuclear energy and coal-fired power for these years. Hence, natural gas will certainly be the main power resource in the future. Unfortunately, the supply of natural gas from foreign countries to Taiwan will be difficult in a foreseeable future. As a result, we have set the process of producing natural gas from an integrated gasification combined cycle (IGCC) power plant to solve this problem. Not only would it solve the issue of providing a constant, supplemental source of natural gas but it also would reduce the pollution of coal power. For this reason, the goal in this thesis which is researching IGCC power plant with the process of producing natural gas in optimization. Moreover, producing 10,000 kilogram per hour of natural gas and earning 12 MW power is our base-case design situation. There are six processes involved in the whole system: (1) raw coal pretreatment (2) coal gasification (3) acid gas treatment (4) shift reactions (5) methanation (6) integrated power system. In addition, we have set the process, which is optimum, into the IGCC system; it would use the resource from this system sufficiently. In other words, in this system, the efficiency will be better than before. After process optimization, we found: (1) By setting the bypass ratio as 0.35 and controlling the two-stage shift reaction feeding temperatures at 290oC and 180oC, respectively, we are able to obtain a H2/CO ratio of 3. (2) When controlling the H2/CO ratio of 3 and maintaining the methanation reactor’s temperature at 240oC, we are able to obtain a mole fraction of methane as 0.936 and reduce the deposit carbon from 18,020 to 16,220 kg/hr. In this research, simulation program Aspen Plus is used to carry out the process synthesis and design. Additionally, Aspen Simulation Workbook is utilized to implement the process optimization.