The safety of the mixed gas production and management

With the need for economic development and the growing market for mixed gas, more and more types of mixed gases, the complexity of the increasingly high, its application areas are related to petrochemical, exploration, metallurgy, machinery manufacturing, electronics, coal , electricity, environmental protection and other fields (process gas or standard gas). In recent years, the process of preparation of the mixed gases often occur some unexpected accident, not only caused the injury, colleagues also caused enormous damage to property. Therefore, to understand and master the properties of gases and materials, designed the filling process, strict operating procedures, clearly identify the dangers of cylinders in order to ensure the preparation and use of mixed gas process safety. Design of a filling system is not incompatible with the filling gas at a filling system. To design two separate filling system, incompatible gases separately. If the connection is incompatible gases simultaneously on a bus, when the valve leakage, high-pressure gas will flow into the low-pressure gas cylinder in incompatible reaction occurs to cause a fire or explosion, at the same time, the operator's erroneous operation may cause unimaginable danger, acid gases and alkaline gases can simultaneously access a system. Beijing-North Cape helium gas Industry Co., Ltd. in the mixed gas filling design combustible gas and oxidizing gas to separate acid gases and alkaline gases separated, mixing equipment were also using two separate systems. Incompatibility 2 gas (1) an oxidizing gas and combustible gas are incompatible. Common oxidizing gases include: oxygen (O2), nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen trifluoride (NF3), fluorine (F2), chlorine (CL2) and so on. Common combustible gas comprising: hydrogen (H2), methane (CH4), other hydrocarbons (alkanes, alkenes, alkynes, etc.), carbon monoxide (CO), ammonia (NH3), hydrogen sulfide (H2S). (2) acid gases and alkaline gases are incompatible. Common acid gas include: hydrogen chloride (HCL), hydrogen bromide (HBr), sulfur dioxide, a common basic gas comprises ammonia (NH3), amines (RNH2) (3) oxidizing gas and reducing gas are incompatible. a. Incompatibility gas 3 gas components and materials under certain conditions and cylinders, valves, piping material incompatibility may lead to the following dangers: 3.1 3.1.1 moisture corrosion corrosion such as HCL, CL2 in the presence of water it is prone to corrosion cylinder, water introduced from the customer may use, the valve is not closed, it may in the course of filling or pressure inspection; NH3, SO2, H2S has similar corrosion. Even dry hydrogen chloride and chlorine, high concentrations can not be stored in aluminum cylinders. 3.1.2 stress corrosion at the CO, CO2, H2O coexist easily corrode steel bottles. Therefore, when a mixed gas containing CO and CO2 preparation, to cylinders for drying, but also the use of high-purity gas raw material gas or moisture-free gas. 3.2 generating dangerous compounds (1) greater than 70% of acetylene and copper of the copper alloy by the reaction of metal organic compounds. (2) single-halogenated CH3CL, C2H5CL, CH3Br and so can not be dressed in aluminum cylinders, they will slow the formation of aluminum metal organic halides, water explosion. If the cylinder contains water, after the preparation of the mixed gas can be detected in the paraffins and hydrogen. 3.3 explosive reaction due to gas valve or pipe sealant material incompatibility reactions cause an explosion. An oxidizing gas such as a combustible valve can not use the sealing material. In the preparation of this mixed gas is easily overlooked. Including how to calculate the oxidizing gas mixture. 4 incompatible gas accident review and analysis of the following is known accidents in recent years in the preparation of: 1996- China Taiwan, N2O / H2, explosion / casualties; 1997- Canada, CO / Air, explosion; 1997 - Britain, CH4 / Air, explosion / casualties; 1997- South America, CH4 / Air, pressure gauge blew; 1997- American, 4% H2 / Air, risk of accidents; 2003- Germany, N2O / CO, personal injury; 2004 - France, halogenated / Air, risk of accidents; 2007- China Lanzhou, CH4 / Air, casualties. Above incidents, mostly formulated combustible gases in air, these gases mostly used in chemical plants, coal gas detection in the environment, the cause of the accident or the wrong operation; or is incompatible gases simultaneously access a system, due to a valve leak generate intrusion; miscalculation or concentration; or is caused by the wrong order filling. For carbon monoxide gas mixture explosion analysis, people tend to pay attention to the toxicity of carbon monoxide while ignoring its flammability. Preparation of the combustible gas in the air often occurs, therefore strict operating procedures is very important. 5 potentially dangerous gas mixture analysis 5.1 identity is unclear or no warning signs (1) mixed gas cylinders should be posted warning labels like pure gas. About flammable or oxidizing gas mixture calculations currently no standard to follow. ISO 10156 is how to calculate the flammable gas mixture and oxidation resistance provides a method to follow. All Beijing helium gas mixture gas-North Cape Air Products and Chemicals Industry Co., Ltd. and other companies to provide gas cylinders warning labels are affixed, cylinders of flammable gas mixture in the bottle shoulder coated with red color ring, to facilitate production management and operator use. (2) mixed gas and pure gas should have the same composition and concentration of the label. (3) should not be left and the concentration of gas or inaccurate labeling, filling the last remaining in the label you want to clean up. Valve outlet thread rules mixed gas valve outlet threaded 5.2 mixed gas to be followed should be followed: a combustible gas mixture - left-handed, non-flammable gas mixture - dextral; mixed gas valve outlet thread currently on the market, most of the production plant to provide no difference , all with the right-handed; mixed gas and pure gas should be the same as the combustible gas mixture using a right-handed thread outlet valve to prevent misconnection and when customers use in the production process; Beijing helium gas-North Cape Industries Ltd. and Air Products Other gas companies follow the above rules valve. 5.3 Gas explosion limit or close to filling process after the explosion range, no concentration and pressure limit as a mixed gas producers, not only to provide the final product to the customer at a concentration of flammable (explosive) below the lower limit, but also in the filling process ensure the safety of the operator, the range for the mixed gas after the explosion in the filling process, the calculation should be rigorously controlled filling pressure and injection sequence, strict operating procedures, the operator should be trained before they can charge after the training of qualified equipment such gases. 6 In addition to potentially dangerous liquid mixture to comply with the same rules and gaseous mixture should be considered: (1) filling is not excessive; (2) to confirm cylinders no margin; (3) electronic scales to be calibrated; (4) siphon filling materials and components must be compatible. 7 monitoring the ambient gas in the production process due to a wide variety of mixed gases, complex components, the leakage of flammable and toxic gases, are likely to produce an accident, so the indoor installation alarm is a necessary condition to achieve safe production, safety, prevention based. In short, the mixing process of the preparation of the gas must be prepared for the mixed gas research, the development of rational filling processes and safety procedures, to provide the necessary safety conditions, production safety first, reduce personal injury and property damage, so as to create a harmonious social environment.