Fire and Explosion Hazard Evaluation and Weighting Analysis of Influence Factors for the Flammable Mixing Solvent by Grey System Theory and 20-L-Apparatus

• Main Authors: Yi-Ming Chang, 張益銘
• Other Authors: Chi-Min Shu
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/30163436819629973499

博士 === 雲林科技大學 === 工程科技研究所博士班 === 98 === Fire safety prevention is today recognized as an imperative necessity and the most constructive campaigns that has ever come into the petrochemical processes and human’s daily lives. This study focused on fire and explosion safety assessment for the flammable materials: (1) benzene and methanol solvent mixtures (benzene/methanol: 100/0, 75/25, 50/50, 25/75 and 0/100 vol.%), and (2) four water vapor (steam)/acetone solutions (steam/acetone: 75/25, 50/50, 25/75, and 0/100 vol.%) both by experimental 20-L-Apparatus investigations and weighting analysis through a soft computing manner of grey system theory. We discussed the effects on influence factors to the flammability properties of foregoing flammable materials with numerious interactive scenarios simulated to their practical plant, comprising (1) benzene and methanol solvent mixtures: different initial temperatures (100, 150 and 200°C), pressures (1, 2 atm), and various loading oxygen concentrations (21, 17, 14…oxygen vol.%); (2) acetone aqueous solutions: different initial temperature (150, 200°C), pressures (1, 2 atm), and normal 21 vol.% loading oxygen concentrateion. Combining with the traditionally-explosion characteristics-detected method via 20-L-Apparatus and mathematical grey system theory apparoach, the experimentally-derived data, including explosion sensitivity (lower explosion limits (LEL), upper explosion limits (UEL)), explosion maximum indices, maximum explosion pressure (Pmax), maximum rate of explosion pressure rise ((dP dt–1)max), explosion hazard degree (gas or vapor deflagration index (Kg)/explosion class (St), and minimum oxygen concentration (MOC), were further employed for weighting analyses of above influence factors via grey system theory, utilizing the GM(h,N) model (GM(1,N)/GM(0,N)) for rating their fire and explosion hazard degrees both specifically and quantitatively. According to our calculation and comparing with the significant part of the above-mentioned influence factors by means of grey system theory, the results indicated that (1) in the benzene/methanol mixing system, the initial pressure was the most important factor among them and should be considered to be controlled first. The second and third factors happened to be loading oxygen concentration and initial temperature, respectively. Furthermore, different benzene/methanol components held no influence in this flammable mixing system; (2) at the acetone aqueous solutions case, the results indicated that the most important influence factor was the initial pressure, the manager or engineer in such a steam/acetone mixing system should be considered to be controlled first. The second influence factor in GM(1,N) and GM(0,N) model was the initial temperature and steam/acetone mixing concentration, but the third influence factor was individual contrariwise. The above testing results were all further confirmed by our theoretical soft computing calculations. In conclusio, this study established a complete flammability hazard evaluation approach that was combined with experimentally and theoretically feasible way for fire/explosion prevention and protection while flammable chemicals were mixed. The outcomes would be useful for positive decisions for safety assessment for the relevant practical plants or processe. First time the traditional way for investigating the flammability characteristics and hazard were further proven by the soft computing methods of grey system theory approach. Regarding to the inert gases selection, this study also could be over employed for the practical applications of inert gases for flammability protection and prevention, to promote the associating process of the whole.