Plantwide Design and Control of Biodiesel Production

• Main Authors: Yin-Heng Shen, 沈胤亨
• Other Authors: Cheng-Ching Yu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/89758023210189320124

碩士 === 國立臺灣大學 === 化學工程學研究所 === 96 === This work explores the design and control of biodiesel production processes. Triglyceride reacts with methanol to form methyl esters and glycerol. The transesterification reaction is catalyzed by homogeneous alkaline, NaOH in this example. Triolein is used to represents refined soybean oil and the vapor-liquid-liquid equilibria are estimated using UNIFAC. The reaction kinetics is taken from Noureddini and Zhu (1997). Because the reactor effluent exhibits phase separation (two-liquid phase), a reaction/separation system is devised to improve the conversion. This is a combined reactor and decanter module with internally recycled glycerol phase which is rich in one of the reactant, methanol. The result shows that, to achieve the same conversion level (99%), the proposed simultaneous reaction/separation system reduces the molar feed ratio (methanol/triglyceride) by a factor of 40%. Next, the design is extended to of the entire biodiesel production plants, including recycle and purification systems. Comparison is made between the conventional and the proposed reaction systems. Design objective is to minimize the total annual cost (TAC) by varying dominant design variables. The results show that a 20% reduction in the TAC can be achieved using the simultaneous reaction/separation system. This also corresponds to a 31% reduction in the energy cost. Finally, plantwide operability of the entire biodiesel production plant is evaluated. The entire plant consists of 35 control loops and simulation results indicate that the proposed process can handle 20% production rate changes with reasonable dynamic performance.