Delayed coking tower and method for preparing needle coke

Abstract

The invention provides a delay coking tower and a method for preparing needle coke by the delay coking tower. The coking tower comprises a cylinder, an upper seal head and a lower seal head. The cylinder comprises a coking section and a packing section which are sequentially arranged from top to bottom, a baffle plate with meshes is arranged between the coking section and the packing section, the coking section, the baffle plate and the packing section are fixedly connected through a flange, an upper feeding port is formed in the coking section of the cylinder, and a lower feeding port is formed in the lower seal head. By the upper feeding mode, disturbance of wide-area intermediate phases caused by feeding is effectively eliminated.

Description

technical field

[0001] The invention relates to a delayed coking tower and a method for preparing needle coke, in particular to a method for preparing needle coke with low coefficient of thermal expansion (CTE) and low volatile content by adopting a delayed coking process. Background technique

[0002] Needle coke has the characteristics of low CTE and easy graphitization, and is the preferred material for the production of high-power and ultra-high-power graphite electrodes. During the formation of needle coke, the raw material oil needs to go through the process of formation, growth and fusion of small mesophase spheres, develop into a wide-area mesophase, and then form a linear texture structure under the action of air flow, and finally solidify Produce needle coke. In the early stage of coking, excessive disturbances in the system should be avoided to ensure the slow and stable development of mesophase spheres. The degree of development of mesophase directly affects the...

Examples

Embodiment 1

[0035]EXAMPLES The delayed coking tower and the method for preparing needle coke according to the present invention are used, the raw material oil and circulating oil are fed from the top, and the substances that are not easy to coke are fed from the bottom to carry out the delayed coking reaction. The height from the upper feed inlet to the bottom of the tower is 4 / 5 of the total tower height, and the height of the packing section at the bottom of the tower is 1 / 10 of the total tower height.

[0036] The raw oil mixed with part of the circulating oil is heated by the raw oil heating furnace and then enters the delayed coking tower with a circulation ratio of 0.8. The raw material oil heating furnace adopts variable temperature control, the initial temperature is 470°C and is maintained for 15 hours, and then the temperature is raised to 510°C at a rate of 4°C / h and maintained for 3 hours; when the outlet temperature of the raw material oil heating furnace reaches 490°C, the lo...

Embodiment 2

[0038] It is the same as in Example 1, except that the raw material oil mixed with part of the circulating oil enters the delayed coking tower after being heated by the raw material oil heating furnace, and the circulation ratio is 1.3. The raw oil heating furnace adopts variable temperature control, the initial temperature is 470°C and is maintained for 15 hours, and then the temperature is raised to 510°C at a rate of 4°C / h and maintained for 3 hours; when the outlet temperature of the raw oil heating furnace reaches 490°C, it is not easy to feed from the bottom of the delayed coking tower The coking substances and the non-coking substances are pre-heated by a heating furnace controlled by variable temperature, the initial temperature is 485°C, and then the temperature is raised to 520°C at a uniform speed within 3 hours, and the temperature is kept constant until the raw oil pump is stopped. Wherein, the feeding amount of the non-coking material is the same as that of the up...

Embodiment 3

[0040] It is the same as in Example 1, except that the raw material oil mixed with part of the circulating oil is heated by the raw material oil heating furnace and then enters the delayed coking tower, and the circulation ratio is 1.5. The raw material oil heating furnace adopts variable temperature control, the initial temperature is 485°C and is maintained for 17 hours, and then the temperature is raised to 515°C at a rate of 3.5°C / h and maintained for 2 hours; when the outlet temperature of the raw material oil heating furnace reaches 490°C, it is not easy to feed from the bottom of the delayed coking tower The coking material and the material that is not easy to coke are heated in a heating furnace controlled by variable temperature in advance, the initial temperature is 495°C, and then the temperature is raised to 530°C at a uniform speed within 3 hours, and the temperature is kept constant until the raw oil pump is stopped. Among them, the feed amount of the non-coking m...

technical field

[0001] The invention relates to a delayed coking tower and a method for preparing needle coke, in particular to a method for preparing needle coke with low coefficient of thermal expansion (CTE) and low volatile content by adopting a delayed coking process. Background technique

[0002] Needle coke has the characteristics of low CTE and easy graphitization, and is the preferred material for the production of high-power and ultra-high-power graphite electrodes. During the formation of needle coke, the raw material oil needs to go through the process of formation, growth and fusion of small mesophase spheres, develop into a wide-area mesophase, and then form a linear texture structure under the action of air flow, and finally solidify Produce needle coke. In the early stage of coking, excessive disturbances in the system should be avoided to ensure the slow and stable development of mesophase spheres. The degree of development of mesophase directly affects the...

Examples

Embodiment 1

[0035]EXAMPLES The delayed coking tower and the method for preparing needle coke according to the present invention are used, the raw material oil and circulating oil are fed from the top, and the substances that are not easy to coke are fed from the bottom to carry out the delayed coking reaction. The height from the upper feed inlet to the bottom of the tower is 4 / 5 of the total tower height, and the height of the packing section at the bottom of the tower is 1 / 10 of the total tower height.

[0036] The raw oil mixed with part of the circulating oil is heated by the raw oil heating furnace and then enters the delayed coking tower with a circulation ratio of 0.8. The raw material oil heating furnace adopts variable temperature control, the initial temperature is 470°C and is maintained for 15 hours, and then the temperature is raised to 510°C at a rate of 4°C / h and maintained for 3 hours; when the outlet temperature of the raw material oil heating furnace reaches 490°C, the lo...

Embodiment 2

[0038] It is the same as in Example 1, except that the raw material oil mixed with part of the circulating oil enters the delayed coking tower after being heated by the raw material oil heating furnace, and the circulation ratio is 1.3. The raw oil heating furnace adopts variable temperature control, the initial temperature is 470°C and is maintained for 15 hours, and then the temperature is raised to 510°C at a rate of 4°C / h and maintained for 3 hours; when the outlet temperature of the raw oil heating furnace reaches 490°C, it is not easy to feed from the bottom of the delayed coking tower The coking substances and the non-coking substances are pre-heated by a heating furnace controlled by variable temperature, the initial temperature is 485°C, and then the temperature is raised to 520°C at a uniform speed within 3 hours, and the temperature is kept constant until the raw oil pump is stopped. Wherein, the feeding amount of the non-coking material is the same as that of the up...

Embodiment 3

[0040] It is the same as in Example 1, except that the raw material oil mixed with part of the circulating oil is heated by the raw material oil heating furnace and then enters the delayed coking tower, and the circulation ratio is 1.5. The raw material oil heating furnace adopts variable temperature control, the initial temperature is 485°C and is maintained for 17 hours, and then the temperature is raised to 515°C at a rate of 3.5°C / h and maintained for 2 hours; when the outlet temperature of the raw material oil heating furnace reaches 490°C, it is not easy to feed from the bottom of the delayed coking tower The coking material and the material that is not easy to coke are heated in a heating furnace controlled by variable temperature in advance, the initial temperature is 495°C, and then the temperature is raised to 530°C at a uniform speed within 3 hours, and the temperature is kept constant until the raw oil pump is stopped. Among them, the feed amount of the non-coking m...

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