The Generation And Prevention Of Shot Coke In Delayed Coking

The quality of delayed coking raw materialsthe is getting worse and production of shot coke is easier with the increasingly poor quality of crude oil.Shaking of coke tower caused by the generation of the shot coke affects the safe production;the shote coke is cheap and has limited use.Therefore,a technical problem for businesses is that how to prevent the production of the shot coke.The effects of the outlet temperature,the pressure of the coke drum,the recycle ratio,the mixing ratio of marley resid and proportion of the slurry oil on the formation of shot coke were studied on the delayed coking unit with the processing capacity of 1 million tons / year.The results shown that reducing the outlet temperatureand the mixing ratio of marley resid,improving the operating pressure,and increasing the recycle ratio and the mixing ratio of the slurry could effectively restrain the coke formation.The optimum process conditions were that furnace outlet temperature was 488 ℃-495 ℃,the operating pressure was 0.18 MPa-0.2MPa,recycle ratio was more than 0.2,the mixing ratio of marley resid was not more than43w%.Two kinds of preventive measures were proposed for preventing the production of shot coke.One was to improve the quality of feedstock oil.The properties of raw oil were improved by adding slurry,which could reduce the generation of the projectile coke.The other was to optimize the operating conditions.The shot coke production could be controlled by reducing the heating furnace outlet temperature,processing amount and the oil-gas line speed,improving the pressure and increasing the recycle ratio.After the shot coke was produced,the countermeasures,such as improving the properties of raw material oil,technological transformation and expansion of coke plant,were put forward.