How to form the hottest electrostatic sparks and h

2022-08-23
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How do electrostatic sparks form? How to prevent effectively

whether electrostatic discharge can produce sparks depends on the discharge energy, not on how many kilovolts the static electricity accumulates. The magnitude of discharge energy depends on the potential difference between conductors and the equivalent capacitance of conductor sound quality. The calculation formula of discharge energy between conductors is as follows:

W = CV2

where: W - discharge energy, J

c - equivalent capacitance between conductors, f

perihelion V - potential difference between conductors, V

from the above formula, it can be clearly seen that the spark generated by electrostatic discharge cannot be discussed only in terms of potential, and when the equivalent capacitance is uncertain, it is impossible to determine how many kilovolts electrostatic accumulation will generate sparks

there is no clear data on the minimum discharge energy that can produce sparks. However, the following data are very important for practical work, but they are still of much worse reference value:

1. When the single pulse discharge energy of induction corona is less than 20 µ J, sometimes sound and light can be generated, and the ignition capacity is very small

2. the discharge energy that can produce medium ignition capacity generally does not exceed 4mj

3. spark discharge between charged metal conductors close to each other has strong ignition ability due to the relatively concentrated release energy

4. When the potential difference between conductor electrodes is less than 1.5kV, alkane petroleum vapor with minimum ignition energy greater than or equal to 0.25mj will not ignite due to electrostatic discharge

5. The induced corona in the local space such as the tip of the grounding needle will not ignite the combustible gas with the minimum ignition energy greater than 0.2mj

6. when loading light oil products, the oil surface potential should be lower than 12kV

how to prevent effectively? (2)

national and industrial standards such as the general guidelines for the prevention of electrostatic accidents (GB) and the electrostatic safety inspection procedures for chemical enterprises (hg/t) have made relatively standardized and perfect provisions. These standards have been included in the practical work manual for chemical safety published this year. Considering that you may not have purchased it yet, the brief answer to how to prevent the harm caused by static electricity in chemical enterprises is as follows:

1. All metal devices, equipment, pipelines, storage tanks, etc. must be grounded according to standards. Metal equipment or metal parts insulated from the ground phase are not allowed. Sub conductor or non conductor shall be indirectly grounded, or electrostatic shielding method shall be adopted, and the shielding body must be reliably grounded

(1) the total leakage resistance of each production device system "or device unit" should be within 1 × Below 106 Ω, the electrostatic grounding resistance of each special device shall not be greater than 100 Ω

(2) if metal flanges are used to connect between metal equipment and equipment, and between pipes, jumper wires may not be connected, but there must be more than 2 bolt connections; The total leakage resistance must be within 1 × Below 106 Ω

(3) when loading and unloading flammable liquids, the truck tanker and tanker that cannot be grounded at ordinary times must be grounded at the preset place according to the requirements of the operating procedures, especially the materials used must be materials that will not produce sparks during impact

(4) large metal devices with a diameter greater than 2.5m or a volume greater than 50m3 should have more than two grounding points, and longer transmission pipelines should be set with one grounding point every M

2. Control the mixing speed of flammable liquid in the reactor according to the operating procedures

"said Dr. Mesut Cetin, product manager of Klaus mafi automation group

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