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Reply To: Quench pipe failure

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Mike Kimbrell

Hydrocyclones have been used to remove solids from the cutting water before storage in the cutting water tank. I would not say that they are common. The flow rate through and pressure drop across the hydrocyclones in important to their efficiency, so the control scheme has to take that into account, if you plan to install them.

A common filter press can be used to remove solids from the system. Other types of filters have been used to remove solids from the cutting water with varying success.

If the drum temperature is not hot enough during the coking phase, sandy coke can be produced that makes lots of fines. A target drum outlet temperature of 440 C should be high enough to fully convert the hydrocarbons in the drum. This target temperature may need to be adjusted depending on feed type and recycle ratio. A high recycle ratio will require a higher drum outlet temperature. A high concarbon feed and low recycle does not need as high of a drum outlet temperature, but 440 C is a good target to start. Measuring the coke HGI (Hardgrove Grindability Index)and coke VM (volatile matter or VCM meaning volatile combustible matter) will provide data to tell if the drum is hot enough during the coking phase.

Coke cutting technique can increase the amount of fines generated removing the coke from the coke drum. Removing coke in as large of chunks as possible should minimize the coke fines and minimize the time to remove coke. Even so, there will be approximately 30% fines in the coke pit so managing the maze and purging the fines out of the cutting water tank are important to cutting water quality.

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