Ethylene Process by China Petrochemical Technology Co., Ltd.

The CBL cracking technology is a steam cracking technology developed by SINOPEC. The steam-cracking furnace for ethylene production can be designed with this technology. This technology provides processing flexibility for ethylene cracking operations and can handle feedstocks from ethane to heavy vacuum gasoil (HVGO).

The CBL technology is a state-of-the-art technology with low-investment cost of building new furnaces or revamping old furnaces. CBL furnace is applicable to many feedstocks such as ethane, light hydrocarbons, natural gas liquids (NGLs), naphtha, light gasoline oil and HVGO. Different feedstocks can be cracked in the same furnace with varying operating condition; two feedstocks (for example, naphtha and ethane) can also be cracked by different coils in one furnace. For heavy feedstocks in particular, the CBL technology shows special advantages—long run lengths (50 days to 70 days) and high ethylene/propylene yields.

For liquid and gas feedstocks, the characteristics of CBL technology are:

Liquid feed:
• Coil configurations. Two-pass, high-selectivity coil configurations (2-1, 2/1-1, 4-1, etc.) are possible furnace designs. The first pass has a small diameter with a large specific surface area, which leads to a quick temperature increase. The second pass has a large diameter, which leads to a lower pressure drop and lower hydrocarbon partial pressure. Appropriate coils are chosen based on different feeds and capacity requirements. The coil configuration of this technology combines the features of higher temperature, shorter residence time and lower hydrocarbon partial pressure and leads to the advantages of high cracking selectivity, long run length and larger capacity of a single coil.
• Transfer line exchanger (TLE). First stage or second stage options available.
• Dilution steam Injection. First stage (light feed) or second stage (heavy feed). By using this technique, coke formation from heavy oil in convection section coils can be minimized.
• Heat supply. Using a combination heat supply from hearth and sidewall allows temperature distribution of the hearth, and the heat transfer of the coil is uniform.
• High thermal efficiency. Up to 93%–94%
• Variable frequency speed control driving motor can be adopted for induced draft fan.

Gas feed:
• For gas feed, the four-pass coil configuration (2-1-1-1) with residence time between 0.4 to 0.8 second is adopted. Linear or U type TLE is directly coupled with the outlet tube of one group of 2-1-1-1 coils. The TLE can be one stage, two stages or three stages. For ethane- cracking furnace, the running cycle is longer than 100 days.

Licensor: China Petrochemical Technology Co., Ltd.

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