Splitting and combining operations for two furnaces with four towers in coking

Do both furnaces need to be fueled when starting up oil heating again? What is the status of the other furnace after feedstock residue oil is fed into it? How long does it take to complete the furnace merging operation, from oil injection to switching the four-way valve? This post was last edited by Bai Ding on 2009-2-12 20:10]

Who needs two furnaces and four towers anymore! ! This results in frequent switching operations of the coke tower, and increases the consumption of utility services during these operations and switching processes.

After the residue oil is fed into the unit, the other furnace is in a state after routine pressure testing. Steam is used for purging before feeding the residue oil, raising the temperature to 400 degrees; then the four-way valve is switched on. It takes about 1 hour for the oil to reach the four-way valve.

The processing capacity of one furnace with two towers is limited; the highest capacity in China is 2.2 million tons per year. Moreover, configurations with two furnaces and four towers, or three furnaces and six towers, have their advantages – if there are problems with a particular tower or furnace, it can be isolated, while the venting system allows for almost continuous operation in systems with three furnaces and six towers.

Yangzi Petrochemical carried out the operation of merging furnaces after implementing line coke cleaning on its 1.6 million tons per year triple-furnace setup; one of their employees even wrote a paper on this topic, which can be used as a reference； Basically, it follows the approach used on the fourth floor: by using steam to heat the furnace to 400 degrees, crude oil can be fed directly, which helps reduce the amount of contaminated oil that is discharged. It is recommended to increase the outlet temperature of the other furnace slightly; this should be done 1–2 hours after feeding material into the coke tower. A temperature of 460°C, or even a little lower, should be sufficient for integrating the new furnace into the system ； It can minimize the spillage of contaminated oil while preventing the formation of soft coke in the coke tower ； I’m not sure if this is correct; I would appreciate guidance from experts in coking.......

Should the flanges of the equipment in front of the furnace be thermally tightened during the steam purging and heating phase, or after the residue oil is introduced?

For thermal tightening of our equipment, we mainly monitor the temperature at the furnace outlet; thermal tightening is carried out at 250°C, 300°C, 350°C, and 400°C. This can be done during the heating phase of the steam purge line or after feedstock oil is introduced, depending on the temperature level.

“\"Steam cleaning raises the temperature to 400 degrees, after which it goes directly into the residue oil.\" Is the steam pressure for cleaning 1.0MPA or 3.5MPA? About how many tons? Should steam be stopped for purging when feeding residue oil? Should it be turned down? If steam cleaning is stopped, will it cause the furnace tubes to overheat due to being empty?

I just saw your post. We have two furnaces with four towers each; we will send you the plan for combining these furnaces tomorrow. One furnace will be used for production while the other is brought online – steam is introduced into the furnace tubes to raise the temperature to 350 degrees, after which residue oil is added. Once the temperature reaches 450 degrees, the four-way valve is switched to rapidly raise the temperature to 490 degrees.

Heat the steam to 350 degrees for thermal tightening, and tighten again after normal feeding.

The plan layout and piping design of the coking furnace in the coke tower of a delayed coking unit are discussed. The characteristics of the plan layout and piping design for the coke tower and coking furnace in Sinopec Yangzi Petrochemical Co., Ltd.’s 1.6 Mt/a delayed coking unit are outlined, including: the elimination of the bypass pipe bridge between the coking furnace and the coke tower, which reduces the length of the oil transfer pipes in the coking furnace and thus lowers the pressure drop; the placement of the oil dumping tank at the bottom of the coke tower; in the design of the oil transfer pipes in the coking furnace, systematic consideration of various factors is applied to keep the stress levels at the outlet points within safe limits; and in the design of the “on-line coking” pipes, elbow connections at specific angles are used.

This post was last edited by yuchenchf on 2014-3-25 at 15:51. Hello, teacher. I would like to ask you about the operation of two furnaces and four towers.

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