Research and Development of An Inherently Safer Process for Cyclohexane Oxidation ---Experimental Studies of Cyclohexane Oxidation Using Pure Oxygen in Counterflow(III)

[[abstract]]本研究在前一年首先針對分散於環己烷液體內的純氧氣泡進行爆燃危害的實驗測試，以瞭解、驗證氣泡爆燃的可能危害，並尋求一液體內氣泡爆燃安全的氣液分散條件，做為本質安全的操作條件。由其結果顯示氣液分散條件與氣泡爆燃關聯不大，是隨時都存在，雖然單獨氣泡爆燃的能量有限不足危害，但當有可燃性氣相空間存在時，爆燃的氣泡可能擴展到氣相空間，導致氣相空間嚴重的爆燃，過壓可超過 10MPa，造成嚴重之危害。在瞭解此一危害特性後，本研究提出一新的反應方式，以管式反應器減少可能之氣相空間與滿槽氣液逆流方式及純氧做氧化劑，可具有使用純氧之高效率與避開氣相空間爆燃的危害，提高單位時間空間的產率。經由批次與連續式的反應測試，證實單位時間空間的產率可達使用攪拌槽與空氣的四倍，達到本質安全化與提升效率的目的。[[abstract]]On our previous year project, we performed experimental studies on the deflagration of high pressure, high temperature oxygen under different dispersion conditions. The aim is to find a criterion for gas dispersion, which renders the deflagration in oxygen bubbles nonhazardous. The results indicate that deflagration of oxygen bubbles is always exist and do not depend on the gas dispersion. Deflagration in single bubble in the liquid is found to produce insignificant energy to endanger the whole reactor. However, the bubble deflagration will propagate to the vapor space and results in severe deflagration. Bearing in mind that the major hazards present in the vapor space, this project proposed a new reaction method that utilize tubular reactor with countercurrent flow of liquid and oxygen under full liquid loading condition. The tubular reactor with full liquid loading reduces the potential volume of the vapor space and its associate deflagration hazards. It is confirmed through batch and continuous reaction tests that the space-time-productivity is almost quadrupled compared with traditional air oxidation process with stirring tank, achieving the aim of an inherently safer and better process for cyclohexane oxidation.[[note]]NSC91-2214-E327-00