丙烯氧化反應製造丙烯酸之製程研究

本研究採用指定溫度形式之填充床反應器進行丙烯氧化反應製造丙烯酸，反應產生之丙烯酸需經過驟冷單元、吸收單元、萃取單元、溶劑分離、酸分離單元，最終產出純度達99.9 mol%，年產量達50,000公噸之丙烯酸。吾人首先透過Aspen Plus進行敏感度分析，分析溫度對選擇率、產率、轉化率、丙烯酸流率、醋酸流率、放熱性能之影響，其結果在 310 - 350oC此溫度範圍時之轉化率與丙烯酸流率最佳，且反應之熱能較少。吾人選用310 oC (丙烯酸流率最佳點) 當作反應器出口溫度。在氧化反應器中需使用可燃物之爆炸界限進行安全評估，結果發現在進料端仍需額外通入約2500 kmol/hr 之氮氣(不參與反應)，方可確保反應器在安全範圍內運作。在節能減碳部分吾人透過Aspen Plus之“Heat X＂模組進行冷熱物流之熱交換，吾人發現在整體製程上節省了8061 kW。在製程經濟評估方面，根據計算整廠之年製造成本為US$100,687,193/yr (不包含折舊)，並由蒙地卡羅法模擬分析，在對企業有經濟效益的情況下，選擇MACRS折舊法計算，平均淨現值為US$40×106、平均投資報酬率為57%、平均回本期為4.8年。本論文之丙烯氧化反應製造丙烯酸之製程設計，主要使用 “Aspen Plus” 化工程序軟體，進行程序合成與設計及換熱器網路合成，而程序流程圖則使用“visio” 繪製。

關鍵字

丙烯酸；填充床；製程安全；經濟評估；蒙地卡羅法

並列摘要

In this research, a packed-bed reactor with a specified temperature mode was used for the production of acrylic acid via the oxidation reaction of propylene. The plant-wide design undergoes a series of units, including oxidative reaction, quench, absorption, extraction, solvent separation and acid purification unit in an attempt to reach the goal of an annual yield of 50,000 tonnes acrylic acid with purity of 99.9 mol%. Sensitivity analysis was conducted by using Aspen Plus. This analysis gives the effects of reaction temperature on the selectivity, yield, conversion, acrylic acid and acetic acid flow rate, and reaction exothermicity as well. The results indicated that conversion and acrylic acid flow rate was at optimum and lesser oxidative reaction heat generated when performed within the temperature range of 310-350oC. Therefore, the temperature of the reactor outlet was set at 310oC (optimal rate of acrylic acid flow). Explosive limits of combustible hydrocarbons in the reactor were evaluated and an additional of 2,500 kmol/hr of nitrogen gas (an inert gas which does not involved in the reaction) was found as a necessity to add in the feed streams so as to ensure the reactor was operated in the safety margin. An overall of 8,061kW of energy was saved from the entire process by conducting heat exchange via the“HeatX” module in Aspen Plus. According to the calculation, the manufacturing cost of the whole plant was estimated at a cost of $100,687,193 per annual (depreciation excluded). In view of the enterprise economic benefit using Monte-Carlo simulation with MACRS depreciation method adopted, we found that the average net present value is US$40×106, the average rate of return on investment is 57%, and the average return period is 4.8 years, respectively. In this study, two kinds of software were used—Aspen Plus and Microsoft “visio.”The former was implemented for the process synthesis and design. The latter was utilized to draw the plant-wide process flow diagram.

並列關鍵字

acrylic acid ； packed-bed reactor ； process safety ； economic evaluation ； Monte-Carlo method

參考文獻

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國際替代計量

丙烯氧化反應製造丙烯酸之製程研究

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