The Invisible Killer in Manufacturing: Static Electricity Explosions and Prevention
Have you ever overlooked the enormous risks lurking in industrial manufacturing environments? It not only causes temporary discomfort but is also an invisible killer that can trigger industrial accidents and explosions. From historical resin factory dust explosions to flammable liquid transport accidents, many tragedies stemmed from the accumulation of static electricity. Therefore, understanding the causes of static electricity explosions and implementing effective preventative measures is crucial for personnel in high-risk industries.
What is Static Electricity? How is Static Electricity Generated?
All objects carry both positive and negative charges. Under normal circumstances, the number of positive and negative charges is equal, resulting in a state of equilibrium. When two objects come into contact, rub, or peel off each other, the negative charge of one object transfers to the other object, which has a stronger attraction for negative charges. This causes an imbalance in the number of positive and negative charges, creating a charged state-this is static electricity.
When is Static Electricity Easily Generated?
Solid Friction or Peeling: Static electricity is generated when materials such as plastics, rubber, and chemical fibers rub or peel off each other.
Dust Flow and Collision: During manufacturing processes, static electricity is generated when plastic powders, chemical powders, metal powders, coal powders, food powders, etc., flow at high speeds and collide with equipment.
Liquid Flow: Static electricity is generated when petroleum, organic liquids, and low-conductivity liquids (such as oil or fuel) flow through pipes, hoses, and filters, or during filling/unloading processes, especially in non-conductive pipelines, rub against and collide with equipment.
Spraying and Coating Operations: Static electricity is generated when high-pressure raw material gases leak in the petrochemical industry, or when gases, liquids, or dust are sprayed from narrow openings. This also includes electrostatic coating processes, where charges are intentionally applied to paint or powder.
Water or Water Jet: Discharge can occur, for example, when water is sprayed to wash oil storage tanks or tank trucks.
Personnel Movement: Friction between the soles of shoes and the floor, or between arms and body, can generate and accumulate static electricity on the body.
Other Industrial Processes: Mixing, stirring, conveyor belts, rapid thermal changes, and two-phase flows (liquid and gas or liquid and solid) are also important sources of static charge generation.
Essential Conditions for Static Electricity Explosion: Three Elements Explained
An explosion will occur when the three elements of "flammable substance," "oxygen," and "ignition source" are present simultaneously. If static electricity accumulates to a certain level and generates heat or sparks, it can combine with flammable substances in the environment (such as gasoline, ethanol, starch, sugar powder, chemicals, etc.) to cause a large explosion, endangering the factory area and personnel. Semiconductor, electronics, panel, paper, textile, printing, chemical, paint, petrochemical, rubber, plastics, power electronics, food processing, and pharmaceutical manufacturing plants are most prone to high-risk explosive environments; therefore, it is crucial to prevent static electricity explosions at all costs.
Industrial Static Electricity Explosion Prevention and Control
Static Electricity Control Standards: Follow systematic and compliant static electricity control standards.
Equipment Selection: In hazardous areas, conductive or anti-static equipment must be prioritized. Special attention needs to be paid to static electricity issues related to the casings, accessories, or coatings of non-metallic equipment due to their insulating properties. Furthermore, explosion-proof static electricity equipment must be used in hazardous areas.
Material Selection: Materials that are inherently conductive or specially treated should be selected to reduce static electricity accumulation. Non-metallic surfaces should possess appropriate conductivity (e.g., electrostatic dissipation or antistatic properties) to allow for slow charge dissipation rather than sudden discharge.
Surface Resistance Control: Control the surface insulation resistance of equipment to reduce static buildup.
Static Elimination Equipment: Install static eliminators, such as ionizing guns, static eliminators, or static neutralization systems, especially for necessary insulators that cannot be grounded (e.g., circuit board materials, certain equipment packages) to neutralize charge.
Grounding Measures: Depending on environmental requirements, conductive equipment can use "grounding" or "bridging" equipment to prevent static buildup and discharge. In hazardous areas, explosion-proof equipment, such as Sanzuo's "explosion-proof static grounding system," must be selected.
Environmental Control: Maintain ambient humidity between 30% and 70% to reduce static electricity generation.
Personnel Guidelines: Workers should wear conductive shoes and antistatic clothing and adhere to electrostatic protection operating procedures.
Regular Inspection: Regularly inspect and maintain equipment to ensure that antistatic functions are normal and effective.
Disaster prevention education and training: Regularly conduct training and drills for employees on static electricity-related knowledge and disaster prevention.