Regarding the location of the oil discharge valve in the coke tower

I have only seen the oil rejection valves installed behind the four-way valve and the feed valve; however, the small-volume steam supply valves are located between the four-way valve and the feed valve as well as behind the feed valve, while the large-volume steam supply valves are situated behind the second oil rejection valve. The small feed water valve is located between the two oil discharge valves, while the large feed water is situated behind the second oil discharge valve. I believe the quality of the position of the oil drain valve can be indicated by the degree of coking on it.

The newly designed oil rejection valve for the coke tower is located behind the feed valve and next to the water and steam supply valves; it can be used for purging during both large and small steam injections as well as when water is supplied, which helps to prevent the accumulation of coke dust. Additionally, oil rejection valves are usually installed in pairs, and there are also a main oil rejection valve, manual valves before and after the oil rejection filter, and valves for feeding into the oil rejection tank. This multi-layered setup is intended to ensure safety, as any leakage of residue oil into the oil rejection tank could be fatal for the coking process. There have been incidents of leaks in the oil rejection valves in the past；

We have a new type of installation: the oil rejection valve is located after the feed valve and next to the water and steam supply valves. I’ve seen this arrangement in several plants; I’ve never encountered a situation where the oil rejection valve is situated between the four-way valve and the feed valve. Personally, I believe the oil drain valve located after the feed valve and next to the water and steam supply valves provides a higher safety factor.

If the coke tower oil dumping valve is located after the feed valve and next to the water and steam supply valves, can the pipeline between the four-way valve and the feed valve ensure preheating before tower switching?

The pipeline between the four-way valve and the feed valve cannot be preheated, but this section is very short (about 80 cm). The high-temperature four-way valve is located nearby, and some heat can also be transferred through the isolation valve on the other side. Additionally, the insulation layer is thick, so although it isn’t preheated, the temperature remains high. This prevents significant deformation or thermal stress when switching the four-way valve；

Currently, the oil rejection preheating valve has two circuits: 1. The Daina oil valve: This valve is located between the coking secondary isolation valve and the water and air inlet valves. It is mainly in the early stage of preheating, when there is a large amount of oil and gas at the beginning, that preheating takes place. This valve has strict requirements. 2. Small oil supply valve: The small oil supply is located between the four-way valve and the isolation valve. Strict preheating requirements apply to the isolation valve. Firstly, opening the oil and gas isolation valve during preheating helps to prevent leaks at the flanges when switching the four-way valve, as a large temperature difference at the four-way valve can lead to leakage. Secondly, the oil that is discharged settles in the dead end between the four-way valve and the isolation valve; when the four-way valve is switched, the high-temperature residue oil coming into contact with this discharged oil can cause fluctuations. Therefore, the small oil supply valve is opened during the preheating of the isolation valve. There are theories regarding the design direction of Xiao Na You, with Jinshan, Takahashi, Qilu, and Yanshan each having their own approaches. 3. Also, note that there should be a anti-coking steam line between the four-way valve and the isolation valve. This post was last edited by kouliang on 2009-3-5 10:47]