Twenty-seven years ago, the flax dust explosion accident in Harbin flax factory killed 58 people and seriously injured 177 people, which made most people realize the dust explosion for the first time. Now, on August 2nd, an explosion occurred in the automobile hub polishing workshop of Zhongrong Metal Products Co., Ltd. in Kunshan Development Zone, which killed 68 people and injured 187 people. This has also attracted our attention to dust explosion. As a form of explosion, dust explosion has not been widely paid attention to because of its particularity, but with the development of China's industry, dust explosion has increasingly become a major obstacle to the safe development of China's industry.

With the progress of industrialization, dust explosions become more and more frequent. Statistics show that there were more than 1000 dust explosion accidents in the United States from 1900 to 1956 * *, and more than 200 such accidents occurred in Japan from 1952 to 1979. 1965 There were 1 173 industrial dust explosions in the United States, with a loss of1/9.4 million dollars, 68 1 person killed and179/kloc-0 injured. With the rapid development of industrialization in China, the number of dust explosion accidents in China shows an obvious upward trend, and the average time between accidents is getting shorter and shorter. According to incomplete statistics, since 20 14, there have been 7 casualties caused by dust explosion. The following is a list of dust explosion accidents since China entered the new millennium:

On June 22nd, 2002, 165438+ Guangzhou Yutaoshan Food Co., Ltd. had an explosion accident of raw material dust, in which 6 people were killed and 12 people were injured.

17 1 person was killed by pulverized coal explosion in Qitaihe, Heilongjiang Province in 2005.

June 5438+10/October 65438+In the early morning of March 2008, the sulfuric acid plant of Kunming Yuntianhua International Chemical Co., Ltd. Sanhuan Branch exploded. The cause of the accident was a fire caused by sulfur dust explosion, which killed 7 people and injured 33 people.

On the afternoon of August 9, 2009, an explosion accident of silicon powder and dust occurred in the new grinding workshop of Hua Kai Tong Yuan Silicon Industry Co., Ltd., Zhejiang Province, causing two employees on duty to burn, one of whom burned 8 1%.

20 10 on February 24th, an explosion accident occurred in No.4 workshop of a famous starch enterprise in China, killing 19 people and injuring 49 others. The accident was caused by dust explosion in the workshop.

20 1 1 On May 20th, an explosion occurred in Chengdu Foxconn Industrial Base, killing three people and injuring 15 people. The accident was caused by the accidental explosion of combustible dust in the dust collection pipeline of polishing workshop.

20 14 dust explosion accident:

65438+1 On October 20th, a metal dust explosion occurred in Huada Chemical Plant, Shishu Village, xinqiao town, Xinbei District, Changzhou, which injured1person and slightly injured two rescuers.

On February 5, an explosion occurred in the starch packaging workshop of Longfeng Corn Co., Ltd., Qinggang County, Heilongjiang Province, which was initially determined to be caused by dust flying. The accident caused 1 employee to die, 1 employee was seriously injured and 8 employees were slightly injured.

On February 8th, Huada Chemical Plant in Shishu Village, xinqiao town, Xinbei District, Changzhou City exploded again after the explosion of metal dust 20 days ago.

On April 16, during the normal production of stearic acid prilling tower of Chen Dong Town Ma Shuang Chemical Co., Ltd., Rugao City, Nantong City, Jiangsu Province, stearic acid dust exploded, killing 8 people and injuring 9 others.

At 4 o'clock on the afternoon of May 27th, a dust explosion occurred in the dust removal room of the truck workshop of Guangdong Yida Textile Co., Ltd. Accessories Packaging Factory, causing five injuries.

On June 2 1 day 17, a dust explosion occurred in a production workshop of Xinjiang Tianyu Biotechnology Co., Ltd. in Wusu City, causing a workshop fire. Fortunately, no casualties were caused.

On August 2nd, an explosion occurred in the automobile hub polishing workshop of Zhongrong Metal Products Co., Ltd. in Kunshan Development Zone, which has caused 68 deaths and 187 injuries.

We will select several typical cases of dust explosion accidents from these accidents for analysis and summary, and remember the past and learn from the future. In the future work, we will minimize the possibility of dust explosion and better protect the life safety and health of employees.

Due to the diversity of industrial dust sources, the study of dust explosion accidents cannot be generalized. Generally speaking, there are three conditions for dust explosion:

(1) combustible dust is suspended in the air at a proper concentration, forming a dust cloud that people often say;

(2) Sufficient air and oxidant;

(3) There is a fire source or strong vibration and friction.

The reaction mechanism can generally be regarded as the following three steps: the first step is the rapid dry distillation or gasification of suspended dust under the action of heat source to produce combustible gas; Step two, combustible gas and air are mixed for combustion; In the third step, the heat released by dust combustion is transferred to nearby suspended or blown dust by means of heat conduction and flame radiation, and these dust are heated and vaporized, so that the combustion cycle can continue. With the advance of each cycle, the reaction speed is gradually accelerated, and finally an explosion is formed through intense combustion. This kind of explosion reaction, as well as the explosion flame velocity, explosion wave velocity and explosion pressure, will be accelerated and increased continuously and develop by leaps and bounds.

Only by mastering the mechanism and conditions of dust explosion can the prevention and control of dust explosion be targeted. If effective ventilation and dust removal measures are taken, smoking and open flame operation are strictly prohibited. Set pressure relief valve or other devices in the equipment shell, and adopt explosion-proof system. Workshops with the risk of dust explosion must be designed in strict accordance with the explosion-proof technical level, and a separate ventilation and dust removal system should be set up. Always wet wash the workshop floor and equipment to prevent dust from flying and gathering. Ensure that the system is well sealed. When necessary, the combustible dust in the closed container or pipeline shall be filled with gases such as nitrogen and carbon dioxide, so as to reduce the oxygen content and inhibit the dust explosion. These can be applied in combination with specific problems.

With the development of production technology towards homogenization and fluidization, there are more and more industries with combustible dust. For example:

Metals: magnesium powder, aluminum powder, zinc powder;

Carbon: activated carbon, electric carbon, coal;

Cereals: flour, starch, corn flour;

Feed: fish meal;

Agricultural products: cotton, flax, tobacco, sugar;

Forest products: wood powder, paper powder;

Synthetic materials: plastics, dyes; Gunpowder and explosives: black powder and TNT.

Combustible dust, like explosive gas, is classified, graded and grouped according to its spark test results. However, the test of combustible dust at home and abroad is not as good as that of explosive gas, so there are few data, and it is difficult to make a scientific division at present. Temporarily divided into three categories (Class I and Class II are explosive gases), and divided into Class A and Class B, as shown in table 1.