InterviewSolution
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Are There Flow Velocity Restrictions To Avoid Static Charge Build Up In Pipelines? |
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Answer» There is an AUSTRALIAN standard "AS1020 (1984) - Control of undesirable Static Electricity" In it, there is a table for flammable HYDROCARBONS as follows: Pipe Size (mm) Max Velocity (m/s) 10 8 25 4.9 50 3.5 100 2.5 200 1.8 400 1.3 600+ 1.0 This is BASED on pure hydrocarbons, and there is a correction, which can be applied for fluids of DIFFERENT conductivity. Methanol has a higher polarity than hydrocarbons and hence is more conductive. The resistivity of diesel is 1013 ohm-m vs 108 for methanol. In addition to this, normal piping design guidelines should however be followed, such as APPROPRIATE earthing, and ensuring exit velocities into tanks of 1 m/s. There is an Australian standard "AS1020 (1984) - Control of undesirable Static Electricity" In it, there is a table for flammable hydrocarbons as follows: Pipe Size (mm) Max Velocity (m/s) 10 8 25 4.9 50 3.5 100 2.5 200 1.8 400 1.3 600+ 1.0 This is based on pure hydrocarbons, and there is a correction, which can be applied for fluids of different conductivity. Methanol has a higher polarity than hydrocarbons and hence is more conductive. The resistivity of diesel is 1013 ohm-m vs 108 for methanol. In addition to this, normal piping design guidelines should however be followed, such as appropriate earthing, and ensuring exit velocities into tanks of 1 m/s. |
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