The Basic Characteristics and Hazard Assessment Of Particular Risk Of Dust Explosion As Well As Security Prevention and Control Countermeasures Analysis

Abstract: China is currently in a period of accelerating industrialization and urbanization. During the economic development process, the increasing emissions of industrial waste gas especially dust have damaged the ecological environment so badly. As a special risk of process industry, dust explosion accidents occur each year in the chemical, coal, metallurgy, wood processing industries which were too numerous to mention. People exert their efforts for up to hundred years in order to prevent dust explosion accidents, but so far, dust explosion is still a serious threat to the safety of  process industry, causing casualties and significant property damage.For that reason, put forward some available security measures based on the analysis of dust explosion hazards, which has become a serious problem demanding prompt solution. For this particular risk of dust explosion, firstly, basic characteristics such as the conditions, procedures and mechanisms were introduced so that we can have a basic understanding of dust explosion; Secondly, combined with significant dust explosion accidents occurred in recent years, analyze three main explosion hazards: strong destruction, prone to secondary explosions, produce toxic gases and then raise hazard assessment method, with using FLACS for accurate simulation and quantitative assessment of the whole explosion process. Next, focus on analyzing the factors of dust explosion such as the dust characteristics, latent solvent strength, potential ignition sources, ambient temperature, flammable gases and inert substances, presenting risk identification methods. Simultaneously, have a experimental analysis for a variety of common dust explosion parameters which have important reference value for dust safety protection through the results of experimental determination. Finally, the latest safety protection methods of dust explosion are summarized, mainly from two aspects that the dust explosion prevention and dust explosion control were discussed. Prevention measures of dust explosion were achieved by drawing up well-established and rational hazard assessment. The highlights of this measure include: rationalization in the industrial layout; prevent combustible dust suspend, reduce dust accumulation and spread range; eliminate dust ignition sources and suppress dust combustion by using inert gases. Control strategies of dust explosion include these following measures: (1) Pressure-proof method. Have a design for silos, pressure vessels and equipment, enable it to withstand the maximum explosion pressure which is a basic and most effective control method. (2) Flame-proof method. Between the two processes interconnecting with each other inside the pipe material, cut off by a certain means to prevent the spread of dust explosion. This method is divided into active isolation and passive isolation. (3) explosion suppression method. Using detectors to monitor the danger signals of dust explosion at manufacturing equipments or work areas, immediately trigger explosion suppression processing systems, rapidly jet inhibitors aiming to prevent the spread of dust explosion and rebirth. All that can reach the purpose of eliminating explosion hazards as a result. (4) vented explosion method. When a dust explosion occurs, a timely manner through a fixed pressure relief opening for release is required, meanwhile, exhaust the high temperature-pressure dust and combustion gases to outside, limit the pressure of dust explosion to a certain numerical value that the container material strength can sustain, reduce explosion damage to facilities and personnel. It is the most widely used explosion-proof method. Safety prevention measures of dust can greatly reduce explosion hazard, provide recommendations for safety and civilized production.

Key words:Dust Explosion; Risk; Hazard Assessment; Security Prevention and Control