RU2433159C1 - Method of producing oil coke - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: coking chambers 8 and 9 are preheated with water vapour, and then - with a combination of a heat-transfer material - heavy cocker gas oil and coking vapours. During heating, the heat-transfer material is supplied to the centre of the coking chamber. The secondary raw stock and the heat-transfer material heated to temperature 400-420C are supplied to the bottom of the coking chambers 8 and 9 separately with the secondary raw stock supplied through a supplementary pipe. While a delayed coking process is performed in the chambers 8 and 9, a coking mass ratchets up. As far as the chambers are filled with the coking mass, the heat-transfer material - heavy cocker gas oil heated to temperature 400-420C in a furnace 3 is supplied to the coking chambers 8 and 9 at first at a level of 1/3, then 2/3 of the heights. ^ EFFECT: invention allows producing oil coke containing high yield volatile substances, prolonging a life length of reaction equipment and reducing time of prior operations of the coking cycle. ^ 5 cl, 1 tbl, 1 dwg

Description

The invention relates to the refining industry, in particular to a method for producing petroleum coke by delayed coking of crude oil.

A known method of producing petroleum coke with an increased yield of volatile substances (more than 15%) by delayed coking of oil residues, in which the above coke is obtained by changing the design of the reactor, for example, the upper part of which has a significantly larger diameter than the rest of the reactor, thereby eliminating the transfer foam into the main distillation column (Pat. CPP No. 71642, IPC СВВ 55/00, op. 29.11.80).

The disadvantage of this method is the heterogeneity of the obtained coke in the reactor volume by the yield of volatiles due to the difference in its diameter. In addition, the implementation of the reactor with different diameters leads to a decrease in its operational reliability.

Closest to the claimed object is a method of producing petroleum coke by delayed coking of oil residues, including heating the coking chamber with water vapor and coking vapors, heating the feed and feeding it to the bottom of the coking chamber together with a heat carrier - heavy coking gas oil (fr. 200-500 ° C) which, before being fed into the coking chamber, is heated to a temperature higher than 50-60 ° C. of the temperature of the coking feed. In addition, the specified coolant is also used for additional heating of the chamber after the supply of water vapor and coking vapor. (Pat. RF №2162876, IPC C10B 55/00, op. 10.02.2001).

The disadvantage of this method is the supply of a coolant heated to a temperature above 50-60 ° C of the temperature of the coking feed (490-500 ° C) together with the coking feed, which does not allow to obtain coke with an increased yield of volatile substances. In addition, when coking in mild temperature conditions (to obtain coke with an increased yield of volatiles), foam is transferred to the distillation column due to intensive foaming of the coked material, which leads to coking of the reaction equipment and premature stop of the coking unit.

The technical result to which the invention is directed is to obtain petroleum coke with an increased yield of volatiles by controlling the temperature regime of coking along the height of the coking chamber with a simultaneous increase in the duration of the reaction equipment.

The specified technical result is achieved by the fact that in the method for producing petroleum coke by delayed coking of oil residues, including heating the coking chamber first with water vapor, then coking vapor supplied to the upper part of the coking chamber and additional heating of the coking chamber with a coolant — heavy coking gas oil, heating the initial and secondary gas oil coking raw materials, heating the coolant - heavy coking gas oil and supplying secondary raw materials and coolant to the lower part of the coking chamber, according to and To the invention, the heat carrier - heavy coking gas oil is heated to a temperature of 400-420 ° C and is fed with secondary raw materials to the lower part of the coking chamber in separate streams with the latter being fed through an additional column, the aforementioned coolant being also fed to the middle and upper parts of the coking chamber when filling the latter, respectively 1/3 and 2/3 of its height, with additional heating of the coking chamber after the supply of water vapor is carried out jointly with the heat transfer medium and coking vapors, the heat transfer agent being heated e is fed into the middle portion of coking chamber.

It is advisable to use FR. As a heat carrier - heavy coking gas oil. 360-380 ° C.

It is advisable to heat the feedstock in an oven to a temperature of 360-380 ° C.

It is advisable to heat the secondary raw materials in a furnace to a temperature of 480-490 ° C.

It is advisable to use the aforementioned coolant for heating secondary raw materials in a heat exchanger.

The supply of coking raw material and coolant — heavy coking gas oil to the coking chamber in separate streams and introducing the latter to 1/3 and 2/3 of the chamber height during coking allows you to adjust the temperature of the top of the coking mass in the most critical zones of its foaming, to control the yield of volatile substances in the resulting coke and also to prevent the transfer of foam into the distillation column and increase the overhaul mileage of the reaction equipment.

The supply of coking feed through an additional column allows, by controlling the saturation of the latter with gas oil fractions, to control the yield of volatiles in the resulting coke.

Combining the operation of supplying coking vapors and heat carrier - heavy gas oil during heating and additional supply of the latter to the middle part of the coking chamber reduces the time of preparatory operations of the coking cycle and, consequently, the time of filling the chambers with coking raw materials, which also increases the yield of volatile substances in the obtained coke.

The attached drawing shows a schematic diagram of the implementation of the proposed method.

The method is as follows.

The feedstock, for example tar from a tank 1 with a temperature of 110 ° C, is pumped through a heat exchanger 2, where due to the heat of the circulation stream of heavy gas oil it is heated to a temperature of 240 ° C, after which it enters the furnace 3 and with a temperature of 360-380 ° C in the lower part of the additional column 4, there is supplied water vapor for stripping boiling fractions contained in the feedstock. From the bottom of the additional column 4, secondary raw materials are fed through the pipe space of the heat exchanger 5 into the reaction coils of the furnace 6, where it is heated to 480-490 ° C. The coolant is pumped through the annular space of the heat exchanger 5 — heavy coking gas oil heated in the furnace 3 to a temperature of 400-420 ° C. In the streams of secondary raw materials supplied to the reaction coils of the furnace 6, a turbulator, for example chemically purified water, is additionally supplied. From the furnace 6, the coking feed is heated to a temperature of 480-490 ° C. through a four-way valve 7 into the coking chambers 8 or 9 with a temperature of 465-475 ° C. In chambers 8 or 9, due to the accumulated heat, the process of delayed coking of the raw material occurs with the formation of a gradually growing coking mass. As the chamber is filled with a coking mass to maintain its top temperature at a level of 400-420 ° С and to prevent the foam from escaping into the distillation column, the coke oven is heated sequentially, first at 1/3, then -2/3 of its height 3 to a temperature of 400-420 ° C coolant is a heavy coking gas oil. At the end of the filling cycle of chambers 8 or 9, a solution of antifoam additive, for example, SKTN-A in light gas oil from tank 10, is additionally fed to the top of the coking mass.

Combined-cycle coking products (coking vapors) are led through the top neck of the coking chambers 8 or 9 to the main distillation column 11 through a helmet pipe for separation into components. In the distillation column 11, the liquid part after stripping flows down, forming a bottoms gas oil, which is collected at the bottom of the distillation column 11 and withdrawn as a component of boiler fuel. From the lower stripping part of the distillation column 11, vaporous products rise upwards - to its strengthening part, equipped with distillation and blanking plates, where the distillate is divided into components: vapor phase, light and heavy gas oils. From the top of the distillation column 11, the vapor phase through a condenser-cooler 12 enters a three-phase gas separator 13, where it is separated into gas, gasoline and waste water.

The heating of the coking chambers 8 or 9 is first carried out with water vapor until a temperature of 110-120 ° C of their top is reached. Further heating of the chambers is carried out simultaneously with a coolant - a heavy coking gas oil with a temperature of 400-420 ° C and coking vapors from working chambers. In this case, heating is carried out in three streams: coking vapors are sent to the upper part of the chamber, and the heat carrier and heavy gas oil are sent to the middle and lower parts. When warming the coking chambers 8 or 9 to a temperature of 360-380 ° C, the heating products from them are transferred to the main distillation column 11, and the coolant is heavy gas oil to be fed to the top of the coking mass. When it is not necessary to supply the coolant to the chambers, to ensure the continuity of the coking cycle, it is provided to be supplied through the heat exchanger 5 to the heavy gas oil line.

Also, with the aim of regulating the quality of the selected coking feed, a heavy coking gas oil is provided from the main distillation column 11 to the additional column 4.

The following are specific examples of the implementation of the proposed method

Table Performance indicators of the delayed coking unit for producing coke with a high content of volatile substances The proposed method Units rev. Example 1 Example 2 1. Feedstock tar tar 2. The heating temperature of the coolant - heavy gas oil coking (FR 360-380 ° C) ° C 420 400 3. The flow rate of the coolant (% wt. From the feedstock) % of the mass. thirty thirty 4. The heating temperature of the feedstock ° C 360 380 5. The temperature of the heating of secondary raw materials ° C 480 490 6. The temperature at the entrance to the coking chamber ° C 465 475 7. Coking time hour 16 eighteen 8. The time of preparatory operations, including the time of heating the coking chambers hour 16 (warming up the camera - 3.5 hours) 18 (warming up the camera - 4.5 hours) 9. Coke yield on feedstock (tar) % mass thirty thirty 10. The maximum level of coke filling of the reactor before transferring the coking mass (foam) to the distillation column m eighteen twenty 11. Maximum coke removal from the reactor m ³ 365.9 413.4 12. Duration of operation of the furnace coil
heating secondary raw materials month 6 8 13. The release of volatiles in coke % 21-25 16-20

Thus, the proposed method allows the coking of oil residues under mild temperature controlled mode to obtain petroleum coke with an increased yield of volatile substances (up to 25%). Moreover, the proposed method allows to increase the overhaul mileage of the reaction equipment - the heating furnace up to 6-8 months, as well as reduce the time of preparatory operations of the coking cycle to 16-18 hours.

Claims (5)

1. A method of producing petroleum coke by delayed coking of oil residues, including preheating the coking chamber with water vapor and coking vapors, additional heating of the coking chamber with a heat carrier — heavy coking gas oil, heating of coking feedstock and secondary raw materials, heating a heat carrier — heavy coking gas oil and supplying secondary raw materials and coolant in the lower part of the coking chamber, characterized in that the coolant is a heavy coking gas oil is heated to a temperature of 400-420 ° C and served with W with raw materials into the lower part of the coking chamber in separate streams with the latter being fed through an additional column, moreover, the aforementioned coolant is also supplied to the middle and upper parts of the coking chamber when the latter is filled by 1/3 and 2/3 of its height, respectively, with additional heating of the coking chamber after water vapor supply is carried out jointly with the coolant and coking vapors, and the coolant during heating is fed into the middle part of the coking chamber. 2. The method according to claim 1, characterized in that the fraction 360-380 ° C is used as the heat carrier - heavy coking gas oil. 3. The method according to claim 1, characterized in that the feedstock is heated in an oven to a temperature of 360-380 ° C. 4. The method according to claim 1, characterized in that the secondary raw materials are heated in a furnace to a temperature of 480-490 ° C. 5. The method according to claim 1, characterized in that the aforementioned coolant is used to heat secondary raw materials in a heat exchanger.