Kettle-type method for preparing needle coke

Abstract

The invention discloses a kettle-type method for preparing needle coke, which comprises the following steps: (1) adding raw oil into a coking kettle, heating to 430-480 DEG C, keeping the constant temperature for 2-6 hours while controlling the pressure of 0.5-2.0 MPa, collecting the discharged oil gas, and separating out 200-400 DEG C fraction; (2) after finishing keeping the constant temperature, closing the exhaust port, cooling the system to 200-400 DEG C, adding the 200-400 DEG C fraction collected in the step (1), and keeping the constant temperature for 1-4 hours; (3) after finishing keeping the constant temperature, and slowly heating the system to 430-500 DEG C, wherein the heating speed is controlled to control the exhaust amount at 0.01-1h<-1> and the system pressure at 0.5-2.0 MPa; and (4) heating the system to 520-550 DEG C, and coking for 1-4 hours, wherein the needle coke generated by reaction is deposited on the coking tower bottom. The method can be used for producing high-quality needle coke; and the operational process is easy to control, is simple and feasible, and is suitable for industrial application.

Description

technical field [0001] The invention relates to a method for preparing needle coke in a kettle, in particular to a method for preparing needle coke with petroleum-based or coal-based raw materials. Background technique [0002] Needle coke is the main raw material for producing high-power and ultra-high-power graphite electrodes, and its economic value is very high. At present, needle coke is mainly produced by delayed coking process, selecting suitable raw materials and obtaining needle coke under suitable delayed coking conditions. When producing needle coke, there are generally high requirements for raw materials. The production technology of needle coke in the prior art mainly focuses on the acquisition or preparation of raw materials, such as CN00125962.8, CN200510073095.0, etc. There are not many improvement plans in itself. [0003] CN01140582.1 discloses a method for preparing needle coke. Put raw materials into a tubular reactor, fill it with an inert gas of 0.1-2...

AI Technical Summary

Problems solved by technology

The above-mentioned invention has the following disadvantages: (1) The invention requires that the material be heated to 480-550°C within 2-30 seconds, which is difficult to realize industrially; , and then the method of preparing needle coke is released during the reaction. Since the inert gas can only be filled into the upper space of the reactor and cannot be dissolved in the material, the gas is released during the reaction, and the flow of the inert gas will not affect the intermediate phase. (3) In the later stage of the reaction, the polymerization reaction is dominant, and the cracking gas generation rate is slowed down, which is not enough to form sufficient side pressure and shear force, so that the entire anisotropic region is forced to align when the gas flow is discharged.

Although the above method solves the problems existing in CN01140582.1 and produces higher-quality needle coke, it still has the following deficiencies: first, it needs to continuously feed inert gas or light hydrocarbon components during the coking process, for Dynamic control of parameters such as temperature, pressure, and exhaust volume brings inconvenience and increases the complexity of operation; secondly, no matter whether inert gas or light hydrocarbon components are blown in from the bottom of the coking tower, the miscibility in the system is poor and it is easy to cause uneven gas flow distribution. Even, resulting in too many local mosaic structures in the obtained needle coke, which affects the performance of the obtained needle coke