Chemical Reaction Is Out Of Control Emergency Relief Study

Emergency venting of runaway reactions is an important safety issue in chemical engineering design~ and is also an active area concerned consistently by researchers. Yet an unitive and exact scheme still has not been worked out due to the complicated runaway process. West countries, especially the United States, set the pace in this field. Many authoritative organizations such as API (American Petroleum institute) and AIChE'S Design institute for Emergency Relief Systems (D1ERS) have presented integrated approach respectively. This paper summarizes the research status of this area since I 960s.The emphasis is laid on the research strategies, design models and experimental methods, and some comments are made on these respects. The purpose of the study in this area is to gain the accurate and safety size of relief devices. Governing equations for relief vent rate requirement can be obtained from the macroscopic energy and mass balance by making some hypothesis's and derivation, which can be used to yield the relief vent requirement for homogeneous venting, all-vapor venting and all-liquid venting. Polymeric reaction, the typical extroexothermic reaction that tends to runaway is introduced briefly. Starting off from the chemical reaction kinetics equation, the reaction velocity equation is obtained. Temperature and pressure histories for free-radix polymeric reaction are obtained by detailed computer simulation based on the equation. Bench scale apparatus that can simulate the nmaway reaction requires high adiabaticity, and automatic control system for temperature and pressure adjustment is needed. In this thesis, by using styrene as reactant, temperature distribution experiments and II maximum runaway pressure experiments are carried out, which help to consider churn-dasher and design pressure of the ultimate equipment container. Based on these experiments, an equipment system is designed and some polymeric reaction experiments are carried out. Besides, data collection program is applied to gather the signals of temperature and pressure. The codes are wrote with Visual Basic 6.0, which is the famous product of Microsoft Corporation. The program calls DLL (li)ynamic Link Library) to gather the signals, the mn-time temperature and pressure histories curves are plotted simultaneously. After the data collection, data is processed and the relief vent size is calculated finally.