Petrochemical enterprises mainly focus on oil, natural gas and other products. In the process of production, processing, handling and transportation, there will inevitably be viscous mixtures or fire-hazardous substances. Therefore, it is necessary to strengthen the process in this process. The explosion-proof design of electrical in petrochemical enterprises, this paper focuses on the analysis of electrical explosion-proof design in petrochemical enterprises from different levels.

The global petrochemical industry started in the 1940s and 1950s and has become an important pillar industry of national economy of different country. The biggest feature of the petrochemical industry is that there are many explosive sources, and most of the reaction materials, media and finished products in its production equipment are flammable and explosive substances. When the mixed gas formed in a certain proportion encounters the fire source and explodes, the degree of harm is very large, which determines the importance of electrical explosion-proof design in petrochemical enterprises.

 

First, the conditions for the explosion-proof electrical design of petrochemical enterprises

Under atmospheric conditions, gases, vapors and combustibles form a mixture with air, ignite and then burn into the environment of the entire unburned mixture, such an environment is called an explosive gas environment, in which petrochemical companies need to carry out explosion-proof design. Specifically, the specific conditions for the electrical explosion-proof electrical design of petrochemical enterprises mainly have the following aspects: First, under electrical conditions, flammable gases, flammable liquid vapors or flammable substances such as mist are mixed in the air to form an explosive gas mixture, and  explosion-proof electrical design is required under such condition. Secondly, in the case of the material operating temperature is higher than the flash point of the combustible liquid, the combustible liquid has the risk of leakage, and the explosive gas mixture formed by the mixture of vapor and air also requires explosion-proof electrical design in this gas environment. Finally, when the flash point is equal to or below the ambient temperature of the vapor of a combustible liquid or the mist and air mixed to form an explosive gas mixture, the explosion proof electrical protection design is still required.

Second, the specific measures of electrical design in explosive gas environments

The above article introduces the conditions for explosion-proof electrical design of petrochemical enterprises, and the following text analyzes and discusses the specific operation process of electrical design.

(1) Clarify the requirements for electrical installations in explosive gas environments

In the explosive gas environment of petrochemical enterprises, the electrical device should also be carried out in accordance with certain requirements, so that the explosion-proof electrical design can be correctly carried out. First of all, the electrical designer needs to formulate a sound explosion-proof design scheme according to the actual situation of the project, and try to arrange most of the electrical equipment, especially the electrical equipment that produces sparks during normal operation, in the area of the danger range, so as to reduce the possibility of explosion and ensure that the electrical design can be safe, scientific and reasonable. Secondly, under the premise of meeting production safety, it is necessary to reduce the number of explosion-proof electrical equipment in the explosive gas atmosphere, and to give priority to safety as much as possible. Finally, in this environment for the explosion-proof design of electrical equipment, but also need to meet the relevant requirements, in the design process involved in the new process must ensure that the electrical equipment in the device meets the requirements, and to ensure that the designer and installer have the level and skill to apply the new process. It is important not to be able to use portable electrical equipment to avoid danger.

(2) The explosion-proof electrical design of petrochemical enterprises also needs reasonable choice of electrical equipment

In the process of selecting electrical equipment, it is necessary to select electrical equipment according to the partitioning of the explosion hazard area, as well as the type of electrical equipment and the requirements of the explosion-proof structure. For the level and group of explosion-proof electrical equipment, it can not be lower than the level and group of explosive gas mixtures in the explosive gas atmosphere, so as to ensure the safe explosion-proof performance of the electrical design. For electrical equipment in areas of explosion risk, it is also necessary to conform to the surrounding environment. In addition, it should be noted that when selecting positive voltage electrical equipment and ventilation systems, it is also necessary to follow the requirements. For the ventilation system, it must be made of non-combustible materials, the structure needs to be strong, and the connection must be ensured to be tight, and there can be no dead ends that produce stagnation. To ensure that the electrical equipment and ventilation system are connected, ventilation is required before the electrical equipment is operated, and it can only be connected to the main power supply of the electrical equipment when the ventilation volume is greater than five times the volume of the electrical equipment and ventilation system. It should be noted that the masonry entering the electrical equipment during operation should ensure that there are no flammable substances, and the electrical equipment needs to have one or several exhaust ports and ventilation systems connected.

(3) Electrical grounding design in explosive gas environment of petrochemical enterprises

In the process of electrical system grounding design, petrochemical enterprises need to follow the requirements, and safety and stability in the first. To this end, it is necessary to design an overall plan according to actual needs, and specify the requirements that the equipotential bonding needs to meet: that is, the equipotential bonding needs to be set in the production device and the protective grounding, lightning protection and anti-static grounding are shared with artificial grounding devices and natural grounding. The bodies are connected to each other to form an equipotential bonding grounding network, and it is necessary to ensure that the network spacing and burial depth meet the requirements. At the same time, it should be noted that in the production plant area, the trunk line of the protective grounding line, various transportation pipes and metal parts in the plant area, and various conductive bodies in the petrochemical enterprise need to be equipotentially connected to ensure safety.

Secondly, the explosion-proof design of the power system needs to be carried out in accordance with the relevant grounding regulations for power equipment. For the parts that do not need grounding treatment under normal conditions, the grounding design still needs to be carried out in this explosive gas environment, such as in a dry environment. Under normal conditions, the metal casing of the equipment whose AC rated voltage is 127V and below, and whose DC voltage is below 110V, still needs to be grounded in the explosive gas environment of petrochemical enterprises to ensure the safety of electrical equipment in the enterprise and the construction environment. security.

Finally, various grounding problems need to be properly dealt with. For example, in an explosive environment, the metal casing of electrical equipment needs to be grounded reliably. In this environment, metal pipelines, metal sheaths of cables, etc. can only be used as auxiliary grounding wires. At the same time, the main lines of the grounding wire should be in different directions in the explosion-hazardous area, and there should be no less than two places; the power equipment and power pipelines should also achieve equipotential bonding, and need to be connected to the grounding grid to ensure the safety of grounding; The grounding device of electrical equipment should be installed separately from the lightning protection device, which can improve the safety index.

 

(4) Electrical circuit design in explosive gas environment of petrochemical enterprises

In such an environment in petrochemical enterprises, the design of electrical circuits is also very critical, and the quality of the design will directly affect the safety performance of electrical explosion-proofing. And security needs to be done.

First of all, for the electrical circuit, it should be laid as far away as possible from the release source, and the cables, light pipes and excavated ditches for laying the wires should be blocked with non-flammable materials. , to avoid danger. It should be noted that in this process, when the electrical line is laid along the pipeline trestle that transports flammable gas, it must be laid along the side of the pipeline with a lower degree of danger, and when the flammable material is heavier than air. When it is necessary to lay it on the top of the pipeline, and vice versa, it should be laid on the bottom.

Secondly, when working in an explosion-hazardous environment such as petrochemical enterprises, the rated voltage of insulated wires and cables used for low-voltage power, lighting lines, etc. must be higher than the working voltage, and not below 500V to reduce the occurrence of explosions. probability.

Finally, it should be noted that in the explosive gas environment, the selection of insulated wires and cable cross-sections should also be carried out according to the requirements, that is, the allowable current carrying capacity of the conductor should not be less than 1.25 times the rated current of the fuse melt; in addition, it is necessary to ensure that the lead voltage It is the long-term allowable current carrying capacity of the squirrel cage motor branch line below 1KV, and it cannot be less than 1.25 times the rated current of the motor.

The petrochemical industry is a dangerous industrial system. Petrochemical enterprises are in an explosive gas environment when they are operating. Therefore, in this environment, explosion-proof design of electrical equipment must be done to ensure the safe operation of electrical equipment in petrochemical enterprises. . Based on this, this paper analyzes and discusses the conditions for explosion-proof electrical design in petrochemical enterprises, and describes specific measures for electrical design in explosive gas environments from four aspects. The help can better promote the safe operation of petrochemical enterprises.