Hot Topics in the Development of Steam Thermal Cracking for Ethylene Production

Those who are conducting related experiments could share their views; it would be good to explain the experimental procedure, the equipment used, and the precautions to take.

“I find that the questioner is like a hunter. When trying to find a specific answer to a general question, especially an engineering or technical one, things often get misdirected and can even become dangerous. Because the person answering the question will easily fall into the trap set unintentionally by the questioner first. Of course, the questioner will not get the real prey they are after. . . ”Zhang, Effective Engineering Design, 1999. If you have any questions or need to discuss specific technical aspects, feel free to contact me at (oneplustech@yahoo.com). Good luck! Zhang

It should be the separation of H2. If H2 separation no longer relies on cryogenic low-temperature separation, the overall energy consumption will decrease significantly, and the capital investment for the facility will also be reduced.

I’m not quite sure what aspects the original poster is looking to understand; I’ll just share my own insights, mainly focusing on the technology related to cracking furnaces. 1. Energy savings and consumption reduction: The main source of energy consumption in steam cracking technology lies in the cracking furnace, which accounts for over 65% of the total energy used in ethylene production. Therefore, finding effective ways to save energy and reduce consumption based on the specific conditions of each plant is a key technical challenge. At present, Sinopec’s plants have started installing air preheaters, but the results vary – this shows that detailed considerations and proper matching are both significant challenges in this field. 2. Preventing coking: The metal components of the cracking furnace tubes act as catalysts for the gases undergoing cracking inside them, which leads to coking. Coking increases thermal resistance, affecting heat transfer and reducing the furnace’s efficiency, thus wasting energy. Moreover, when thermal resistance becomes too high, higher temperatures are required in the tube walls to achieve the same level of cracking. However, metals have a limit to their heat tolerance, and beyond that limit, there is a risk of the tubes being damaged. As a result, it’s necessary to shut down the furnace every 30 to 100 days to remove the accumulated coke； Currently, the main technologies for suppressing coking include coating techniques, methods to improve the properties of furnace tube materials, and the use of coking inhibitors. Among these, I am most optimistic about improving the properties of furnace tube materials, such as addressing the industrialization of ceramic furnace tubes.

I agree with what was said above; the main goal is to extend the operating time of the pyrolyzer. Currently, the feedstocks for ethylene cracking are increasingly tending to be heavier. Therefore, technologies to suppress coking are currently a hot topic. Another aspect is modifying the pyrolysis furnace to enable it to handle a wider range of feedstocks. This is just my humble opinion; I’m a newcomer, so please be kind to me.

It mainly involves extending the operating time of the pyrolyzer. Currently, the feedstocks for ethylene cracking are increasingly tending to be heavier. Therefore, technologies to suppress coking are currently a hot topic. Another aspect is modifying the pyrolysis furnace to enable it to handle a wider range of feedstocks. Could someone give some more advice?

However, the costs required to improve material properties, including time and money, are quite substantial. And it may not necessarily be successful. Which domestic company is willing to take this risk? Regarding furnace tube coating technology, a few years ago Yangzi developed a furnace and carried out the lining of its furnace tubes; it is said that the results were quite good. I heard that another one is going to be built next year. However, this technology is not yet mature in China, and there are no precedents for large-scale production. Someone in Yangzi has conducted a thorough analysis of the lining technologies used by various manufacturers; it seems to me that they use a technology provided by an American company.

The use of the pyrolysis furnace tube heat transfer enhancement technique (i.e., the twisted sheet technique) features low cost and rapid results, and is applicable to both new and existing plants. If it is vigorously promoted, it will make a significant contribution to energy conservation and emission reduction.