Factors and preventive measures of nitrogen suffoc

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Factors causing nitrogen suffocation accidents and preventive measures

in the production process, due to the lack of sufficient attention to nitrogen, the knowledge of nitrogen is not comprehensive, and nitrogen suffocation accidents also occur from time to time in the country. A few days ago, the safety accident of suffocating one person due to nitrogen in dry quenching sounded the alarm with bloody facts: in the production process, we must pay great attention to nitrogen, understand the characteristics of nitrogen, fully understand the harmfulness of nitrogen, and strengthen the safe use of nitrogen

I. characteristics of nitrogen

property introduction: in the air, the content of nitrogen is 78.14%; Oxygen 20.9%; Hydrogen 0.93%; There are also a small amount of carbon dioxide, helium, neon, krypton, xenon and water vapor. Nitrogen is a colorless, tasteless and odorless inert gas; The chemical property is not active, and it is very inert under normal conditions, so it is not easy to react with other substances. At standard atmospheric pressure, the boiling point of nitrogen is -195.80 ℃ (77.35k)

production method: it mainly uses the different boiling points of oxygen and nitrogen under low temperature to separate pure oxygen and pure nitrogen from the air in the development space of China's plastic machinery dispensing structure to improve the extruder industry by distillation for production and non production processes, such as using nitrogen for instruments as purging gas, CBD rotary sealing valve as gas seal, etc. During the preparation and use of nitrogen, nitrogen suffocation accidents may occur due to the leakage of production devices and process pipelines, the failure of safety devices, and the failure of safety devices in the maintenance process due to the failure to wear safety protective equipment or improper protection

asphyxiation mechanism: nitrogen, carbon dioxide, methane, acetylene, neon, etc. are all direct asphyxiating gases. Its characteristic is that the increase of its own concentration leads to the decrease of oxygen content in the air and asphyxia. Generally, when the oxygen content in the air is less than 18%, suffocation accidents will occur. Nitrogen itself is not harmful to human body. If the nitrogen concentration is slightly high, personnel will have mild headache, nausea, vomiting, hallucinations and excitement symptoms. In this case, if the ventilation conditions are improved early and in time, the patient will recover quickly. If the nitrogen content continues to increase, the oxygen content in the air will be reduced, making it difficult for people to breathe. If pure nitrogen is inhaled, asphyxiation or even death will be caused by severe hypoxia

hazard of suffocation: nitrogen is a colorless, tasteless and odorless inert gas, and it is not possible to judge whether nitrogen in a relatively closed space exceeds the standard only by senses. When the oxygen concentration in the air decreases, the occurrence of asphyxiating accidents often has no obvious warning. According to records, when a nitrogen suffocation accident occurs, it is difficult for the victim to escape or save himself as long as he stays in a relatively high concentration of nitrogen space for 2 minutes; When the oxygen concentration in the working space is less than 10%, people can immediately suffocate and die

II. First aid cases of nitrogen suffocation

it is particularly suitable for molding under high temperature (100 (1) 50 ℃

example 1: the occupational disease department of Laiwu Iron and Steel General Factory Hospital in Shandong Province admitted 6 cases of acute nitrogen poisoning in June 1996. The accident occurred in the oxygen production workshop of the power department. The raw material of the workshop is air, and the products are pure oxygen and nitrogen. Process flow: air suction → automatic opening of filtration → compression → precooling → air purification system → air separation tower. The purification system uses silica gel to adsorb hydrocarbons in liquefied air, and the silica gel in the adsorber needs to be replaced regularly. Replacement process: pure nitrogen is introduced into the adsorber for heating → the valve is opened → silica gel falls into the incubator → workers go down the ladder from the top of the incubator to replace it. This box is located on a 1m high platform with a volume of 3M × 2.5 m × 5 m, and the opening area of the box top cover is 1 m × 1 m。 20 minutes after the accident, the workshop laboratory sampled and measured the nitrogen concentration in the box as 85.2%, and the oxygen concentration as 9.6%

poisoning process and manifestations: the six victims were male, aged 24-47 years, and were maintenance fitters. Due to the wrong operation, nitrogen leaked into the incubator, and all 3 machines could not operate normally. About 2 minutes after entering, the workers felt dizzy, chest tightness and general fatigue. Two first entrants were unconscious due to suffocation, and one second entrant was still able to call for help. When he wanted to escape, he lost consciousness near the ladder in the incubator. Three workers waiting on the top of the box entered the box without any protective equipment and collapsed in the box one after another. Other workers in the workshop wore oxygen supply masks to rescue 6 patients, and 3 workers were found to vomit stomach contents; Two patients were incontinent; 4 had irritability; Two patients had convulsive symptoms. The victim stayed in nitrogen for 5-20 minutes. The time from rescue to treatment is about 15 minutes

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