Safe operation of explosion-proof electrical equipment in oil depot
★Safety and environmental protection technology of petrochemical industry ★ Safe operation of explosion-proof electrical equipment in fire prevention and explosion depots Ren Junqiang (68090 Unit of Lanzhou Military Region, Xi'an 710038, Shaanxi Province) The characteristics of the oil depot industry mainly established the principles and basis for the selection of explosion-proof electrical equipment, and introduced explosion-proof lamps and lanterns. Installation, steel pipe wiring, cable line connection and cable introduction of explosion-proof equipment should pay attention to and grasp the problems, from maintenance, repair, replacement and rectification of explosion-proof electrical equipment put forward measures to strengthen the safe operation and management of explosion-proof electrical equipment. Explosion-proof electrical equipment (hereinafter referred to as equipment) is an important part of the safety of oil depots. High technical, reliability, and safety requirements, and negligence in the use and management of the equipment can cause an explosion and fire accident. The correct selection of equipment, strict operating procedures and regular maintenance are the important means and effective ways to ensure the safe operation of oil depots and prevent accidents. 1 Reasonable selection of equipment The correct selection of equipment is the first step in preventing fire explosion accidents. It must be selected scientifically and reasonably according to the requirements of explosion hazard zone levels and explosion-proof electrical structures. 1.1 Selecting type according to basic principles Focusing on safety, we must try to select equipment with reasonable structure, advanced technology, convenient installation, easy operation and maintenance, and focus on checking whether there are defects or hidden dangers and send it to the quality inspection department for inspection if necessary. With emphasis on adaptability, the equipment should meet the requirements for equipment in different environmental conditions such as chemical, mechanical, thermal, mold, and sand in the environment. The structure should meet the requirements of the specified operating conditions without reducing the explosion-proof performance. Attention to economics, as long as the explosive mixture level, group and environmental requirements can be met, it is not appropriate to choose a higher level in order to improve safety, and at the same time, comprehensive analysis of operating costs, energy consumption, maintenance, life, etc., in order to select the most economical Reasonable equipment. Consider aesthetics, appearance should be meticulous, smooth, smooth lines, no obvious bumps or prominent flaws, the surface paint layer smooth, solid, solid, moderate luster, the color meets the coloring regulations, the size and shape of the signs and materials in line with national standards Wait. 1.2 According to the level of explosive danger zone, the explosive danger zone of different grades and structures of equipment shall be determined, and the type of explosion protection adopted by the equipment shall also be different. Only by correctly classifying explosion hazard places can the equipment be reasonably selected. According to the provisions of the design code for explosion and fire hazardous electrical installations (GB50058-2) and the possibility of the formation and accumulation of oil depots forming explosive gas mixtures, the explosion hazardous locations are divided into three regional levels. Zone 0 (referred to as zone 0) refers to areas where explosive gas mixtures occur continuously or over a long period of time. Level 1 zones (referred to as zone 1) are areas where explosive gas mixtures may occur during normal operation. Zone 2 (referred to as Zone 2) is an area where explosive gas mixtures are unlikely to occur during normal operation and, if present, occurs occasionally and only for a short period of time. Normal operation refers to the operating condition of the device within its design parameters. When classifying explosion hazardous areas, comprehensive evaluation shall be made according to various factors, such as physical and chemical characteristics of oil products, specific operating characteristics, equipment performance, configuration, and temperature, air pressure, wind direction, location of buildings (structures), etc. Commonly-used equipment explosion-proof structure types mainly include: explosion-proof type d, increased safety type e, intrinsically safe type ia/ oil product application chemistry department oil management professional, now engaged in troop oil depot management, 68090 unit deputy chief, has published 7 ★ Ren Junqiang. The safe operation and management of the explosion-proof electrical equipment in the oil depot should be selected from explosion-proof or increased safety explosion-proof structures. Flameproof and increased safety equipment can only be used in Zone 2. Places at all levels do not use positive pressure or oil-filled equipment. 1.3 Determining the type, grade and group of equipment The type, grade and group of explosive gas mixtures are important parameters for the classification of explosion-proof zones and the selection of equipment. The explosive substances are classified into three categories: i is mine methane, n is an explosive gas mixture, and m is explosive dust. The explosive gas mixture is classified according to its maximum test safety clearance (MESG) and minimum ignition current ratio (MICR) and is divided into A, B and C grades. The smaller the maximum test safety clearance, the greater the explosion risk of the gas mixture; the smaller the ignition current ratio, the smaller the ignition energy required for the gas mixture, the greater the danger. When tested in accordance with standard test methods, the lowest temperature at which an explosive mixture is ignited is called the ignition temperature. According to the ignition temperature, the explosive gas and vapor mixture can be divided into six groups of T1 to T6. The equipment is divided into two categories based on its use: Category I refers to equipment used in underground mine explosion hazardous locations, and Category n refers to equipment used in ground explosion hazardous locations. The equipment level and group selected should not be lower than the level and group of explosive gas mixtures in the environment. When there are two or more kinds of explosive gases in the site coexisting or alternating, they should be selected with high degree of danger and group. 2 correctly install the equipment 2.1 Explosion-proof lamps Explosion-proof lamps are the most commonly used equipment in the oil depot. Spiral light bulbs should be tightly tightened, with good contact and no loosening. Lamp housings should be complete and bolts should be fastened. Do not change the type, type and power of the luminaire. 2.2 Pipeline distribution Lines of steel within the explosion hazard zone shall be made of galvanized welded steel pipes for the transport of low pressure fluids. The wiring installation of the steel pipe must be fixed and reliable, and shall not be used as a support for other articles. The connection between the steel pipe and the steel pipe, the steel pipe and the equipment, the steel pipe and the steel pipe attachment shall be threaded, and no pipe connection shall be adopted. The pipe diameter shall be 25mm or less. Should not be less than 5 buckles. Exposed threads should not be too long. Pipeline wiring should be equipped with explosion-proof flexible pipe at the motor inlet, pipeline and electrical equipment connection difficulties, pipeline through the building expansion joints, settlement joints. 2.3 Connection of cable lines The electrical lines of explosion hazardous locations should be steel pipe or cable wiring. The cable should not have intermediate connectors. When it is difficult to avoid, it must be connected in the corresponding explosion-proof terminal box or junction box. The terminal box must not be buried (walls) ). Cables for different purposes shall be laid separately. The power and lighting circuits must be separated. It is forbidden to use them together. Cables and steel pipe wirings shall not be laid in pipe trenches or ventilation trenches. No intermediate joints or buried junction boxes are permitted for buried armored cables. Wire connections shall be fixed or crimped or welded with bolts against loosening and shall not be wrapped. When copper and aluminum wires are connected to each other, a copper-aluminum transition joint must be used. Cables should be protected by thick-walled steel pipes through floors, partitions, and places subject to mechanical damage. The gap between the protection pipe and the building shall be sealed with cement mortar. Both ends of the protection pipe shall be sealed with non-combustible sealing material. The clogging thickness shall be greater than 1.5 times the inner diameter of the steel pipe and shall not be less than 50mm. 2.4 Flameproof equipment Cables introduced into the flameproof devices of the cable cannot be easily sealed using elastic sealing rings or packings. When the explosion-proof equipment does not contain a little source inside, in principle, an elastic sealing cable type cable introduction device can be used to introduce the cable. When the explosion-proof electrical equipment contains an ignition source, the nA, nB and nc flameproof enclosures whose enclosure volume is greater than 2L are not allowed to be directly introduced by the elastic cable-type cable entry device, in order to use the elastic seal type. The cable entry device should use indirect introduction. In addition, the nominal diameter of the flameproof device introduction device should correspond to the maximum outer diameter of the cable. 3 pay attention to maintenance and repair to regularly wipe the surface of the equipment, remove or clean the equipment surface and internal adhesion of mud, grease, etc.; to paint, corrosion of the surface of the anti-corrosion coating treatment, add or replace the insulating oil, grease ( oil). Repair damaged parts and components; replace deformed and damaged sealing rubber rings, rust, damaged terminals, and damaged connecting bolts and gaskets; repair failed flameproof joints; measure and adjust explosion proof Clearance value. It is necessary to promptly replace the equipment that has been identified as being scrapped. After the overhaul, the quality standard can be met, but the overhaul time is long. The overhaul cost is greater than or close to the cost of purchasing the same equipment, which is economically uneconomical. Non-explosion-proof electrical equipment installed in hazardous areas and equipment that does not meet explosion-proof requirements must be properly repaired according to specific conditions. For example, the treatment of non-explosion-proof electrical equipment in the distribution center of the cave tunnel, or the change of the equipment to an explosion-proof type, or the transfer of a more complex distribution cabinet to the power distribution room in a safe area, where only simple explosion-proof is installed Switch and so on. LWBS takes your comfortable bathing as the source of our designing and Floor drain products KaiPing HuiPu Shower Metalwork Industrial CO,LTD , https://www.hp-shower.com
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