[Q&A Question 134] 2016.09.01
Thread Content
【Q&A Question 134】September 1, 2016: What are the reasons that cause furnace tubes to burn out? The answer key can be seen after responding; scoring is based on identifying the key points. 1. Uneven heating of the furnace tubes, with the flame hitting the tubes, resulting in localized overheating of those tubes. 2. Insufficient feed rate, leading to an excessive residence time of the material inside the furnace tubes. 3. Excessively high temperature in the furnace chamber, which causes the oil to coker. 4. Residual coke inside the furnace tubes, which acts as a catalyst for the formation of new coke.
The possible reasons are: low ventilation volume and high steam flow; low furnace temperature, resulting in the coke not reaching the combustion temperature; coking of the furnace tubes
1) Local overheating due to uneven heating, with excessively high temperature at the furnace outlet； 2) Vacuum in the radiation feed pump or large fluctuations in the feed rate cause significant fluctuations in furnace temperature ； 3) Low steam injection volume or interruption ； 4) Raw materials containing many impurities such as sulfur and salts are prone to decomposition ； 5) Incomplete burning, with residual old burns remaining ； 6) A blocked backflow path or excessive pressure in the coke tower results in a slow flow rate of residue oil.
Abnormal combustion, flames licking the furnace tubes, low water-to-carbon ratio, severe carbon deposition on the conversion catalyst, excessive impurities in the raw materials, and so on
The crude oil becomes heavier, the temperature exceeds the limit, there is flow deviation, the flame touches the furnace tubes, and uneven burning occurs!
Improper operation, issues with raw materials and ingredients
The material is incorrect； Dry-frying ； Improper furnace temperature control ； Scour protection plate failure
1) Local overheating due to uneven heating, with excessively high temperature at the furnace outlet； 2) Vacuum in the radiation feed pump or large fluctuations in the feed rate cause significant fluctuations in furnace temperature ； 3) Low steam injection volume or interruption ； 4) Raw materials containing many impurities such as sulfur and salts are prone to decomposition ； 5) Incomplete burning, with residual old burns remaining ； 6) A blocked backflow path or excessive pressure in the coke tower results in a slow flow rate of residue oil.
Nozzle misfiring, secondary combustion, flame too long, negative pressure too low
Reasons: 1. Uneven heating of the furnace tubes, with the flame hitting the tubes and causing localized overheating. 2. Insufficient feed rate, resulting in a prolonged residence time inside the furnace tubes. 3. Excessively high furnace temperature, which leads to coking of the oil. 4. Residual coke inside the furnace tubes, which acts as a catalyst for the formation of new coke.