Regarding the cleaning of coal tar mass flow meters
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Our company uses Rosemount high-temperature flowmeters for measuring the mass flow rate of crude oil. Once, coking and blockages occurred due to the poor quality of coal tar; however, the crude oil passed all inspection tests upon arrival at the plant. I have two questions for everyone: First, how should the flowmeter be cleaned? Second, regarding the reasons for coking of coal tar that were proposed earlier, I am very interested in understanding the principle behind coking of coal tar, and how coking can occur at such low temperatures (definitely below 200 degrees)
1. The flow meter can be cleaned with cleaning oil. 2. Could the coking of coal tar be due to the precipitation of naphthalene?
The reason might be that the quality of your raw materials is not very good – they contain many impurities which gradually accumulate on the flow meter. The flow meter can be cleaned by soaking it in cleaning oil, and then blown clean with steam
Although the tar test results from your factory are satisfactory, it may contain tiny particles such as large tar residues, which can cause blockages when passing through the mass flow meter; it’s not actually coking. Try rinsing it with cleaning oil. In our plant, using a mass flow meter works well for tar after deslagging it with a super centrifuge; however, asphalt mass flow meters suffer from blockages when the QI content is high. We are now planning to replace them with vortex flow meters
It’s definitely not coking; it’s tar residue. This slag dissolves in asphalt but not in washing oil. The crude oil should be the crude oil used for producing carbon black, right? Is coal tar used directly? Not extract the light components?