RU2272063C1 - Heavy petroleum residue visbreaking process - Google Patents

Abstract

FIELD: petroleum processing.

SUBSTANCE: process comprises heating heavy petroleum residue to visbreaking temperature, ageing visbreaking products in adiabatic tubular reaction (with length-to-diameter ratio above 200) to produce gas, gasoline fractions, and visbreaking residue. To control extent of the process and degree of viscosity fall for visbreaking residue, carrying gas, in particular water steam or inert gas, is introduced into reactor. Process allows production of fuel oil from black oil.

EFFECT: reduced rapidity of coke formation in reactor, simplified cleaning or reactor walls, and enabled visbreaking extent control.

3 cl, 1 tbl, 6 ex

Description

The invention relates to the field of oil refining, in particular to a method for producing boiler fuel from oil residues, and can be used to deepen oil refining.

A known method for producing boiler fuel, including heating a heavy oil residue to a temperature of visbreaking in the coils of a tubular furnace, cooling visbreaking products to a temperature of cessation of coke formation reactions (400 ° C) by supplying a cooling product (cooling) to prevent coke deposits in the distillation column, separation Visbreaking products for gas, gasoline fractions and residue (boiler fuel). The depth of visbreaking, the material balance of the process, and the degree of viscosity decrease of the visbreaking residue are controlled by changing the final temperature of the raw materials in the furnace [Varfolomeev DF, Fryazinov VV, Valyavin GG Visbreaking of oil residues. Express information. Thematic review. M .: TsNIITEneftekhim, 1982, p. 9-11].

The disadvantage of this method is that due to the short residence time of the raw materials in the furnace coils and to ensure the necessary depth of visbreaking, it is necessary to maintain an elevated temperature in the furnace coils (470-500 ° C), which leads to their coking and the installation to clean the coils from stopping coke deposits.

Closest to the claimed object is a method of visbreaking a heavy oil residue, which consists in the fact that the oil residue is heated in the coils of a tubular furnace to a temperature of visbreaking (450-460 ° C) and fed to a vertical cylindrical adiabatic reactor. Due to the sufficiently large volume of the heated feedstock in the reactor, endurance and, accordingly, the necessary depth of visbreaking are provided [Varfolomeev DF, Fryazinov VV, Valyavin GG Visbreaking of oil residues. Express information. Thematic review. M .: TsNIITEneftekhim, 1982, pp. 26-27].

The disadvantage of this method is the low speed of the movement of visbreaking products in the reactor, which leads to the formation of coke and its deposition on the walls. Over time, the entire reactor volume is filled with coke, and the installation is stopped for cleaning. Cleaning the reactor from coke compared to cleaning the pipe is a very time-consuming procedure and is carried out mainly manually with jackhammers.

In addition, due to the random movement of the feed stream in the reactor, which is typical for large-diameter apparatuses, there is an unequal residence time of various portions of feed in the reactor, which contributes to the formation of a stream that is heterogeneous in composition and reduces the efficiency of the visbreaking process, and also makes it difficult to control the depth visbreaking.

The invention is directed to reducing the rate of deposits in the reactor and simplifying the process of cleaning a visbreaking reactor while increasing the efficiency of the process by reducing the duration of the visbreaking process to a predetermined depth.

This is achieved by the fact that in the method of visbreaking a heavy oil residue, including heating the oil residue to a temperature of visbreaking (450-485 ° C), holding the visbreaking products in an adiabatic reactor to produce gas, gasoline fractions and visbreaking residue, the reactor is made tubular with respect to the length of the tubular reactor to a diameter of more than 200.

In addition, at the inlet to the reactor serves a transporting agent, which is used as water vapor or inert gas.

The method is as follows.

The oil residue, such as tar, is heated to a visbreaking temperature (450-485 ° C) in the furnace coils and sent to a tubular reactor, which is protected from heat loss into the environment by a layer of thermal insulation.

Due to the heat imparted to the oil residue in the furnace, visbreaking reactions continue in the tube reactor, resulting in an increase in visbreaking depth. The temperature of the products due to the occurrence of endothermic reactions is gradually reduced.

The speed of movement of visbreaking products in a turbulent flow due to the small cross section of the tubular reactor is high enough, which significantly reduces the rate of coke deposition on the walls of the reactor. Due to the fact that, according to the operating mode, the tubular reactor is an ideal displacement reactor, it ensures uniform flow composition within its cross section, which contributes to a more intensive flow of the visbreaking process.

The method comprises supplying a transporting agent, for example, water vapor or an inert gas, to the tubular reactor. By changing the residence time of the reaction products in the reactor by changing the flow rate of the transporting agent, the depth of visbreaking is controlled.

The deposits formed on the walls of the reactor can be easily cleaned using the traditional steam-air method.

The proposed method is illustrated by examples.

Example 1 (by analogy). The tar of West Siberian oil at a flow rate of 115,000 kg / h was heated in a tubular furnace to a visbreaking temperature of 485 ° C and cooled at the outlet of the furnace to 400 ° C by supply of cooling. The average velocity of the products in the reactor was 30 m / s. The continuous operation of the coil before stopping for cleaning was 3 months. The duration of coke removal from the reactor was 2 days. During the year, 4 cleanings were carried out. The total cleaning time is 8 days. The degree of decrease in viscosity of the residue is 13.5.

Example 2 (prototype). The same tar at the same flow rate was heated in a tube furnace to a visbreaking temperature of 450 ° C and sent to a vertical cylindrical adiabatic reactor. The average velocity of the products in the reactor was 0.2 m / s, and the reaction time was 75 s. The duration of the continuous operation of the installation to a stop to clean the reactor from coke was 12 months. During the year, 1 cleaning was carried out, which was carried out mechanically using hand tools. Cleaning time - 10 days. The productivity of the installation compared to example 1 decreased by 27,600 tons / year. The degree of decrease in viscosity of the residue is 19.2.

Example 3. The same tar at the same flow rate as in Example 1 was heated in a tube furnace to a visbreaking temperature of 450 ° C and sent to an adiabatic tube reactor with an internal diameter of 402 mm and a length of 150 m, equipped with thermal insulation. The average velocity of the products in the reactor is 8.0 m / s, the reaction time is 18.8 s. The duration of the continuous operation of the installation until it stops to clean the reactor from coke is 12 months. The duration of coke removal from the reactor is 2 days. During the year 1 cleaning was carried out. The increase in the duration of the installation compared to the prototype (example 2) is 8 days, while the productivity of the installation increased by 22080 t / year. The degree of decrease in viscosity of the residue is 22.5.

Example 4. The same tar at the same flow rate as in Example 1 was heated in a tube furnace to a visbreaking temperature of 450 ° C and sent to an adiabatic tube reactor with an internal diameter of 402 mm and a length of 150 m, equipped with thermal insulation. At the inlet of the reactor, a transporting agent (steam) was supplied in an amount of 1000 kg / h. The average speed of the products in the reactor is 9.0 m / s, the reaction time is 17.1 s. The duration of the continuous operation of the installation until it stops to clean the reactor from coke is 12 months. The duration of coke removal from the reactor is 2 days. During the year 1 cleaning was carried out. The increase in the duration of the installation compared with the prototype (example 2) is 8 days, the productivity of the installation increased by 22080 t / year. The degree of decrease in viscosity of the residue is 19.2.

Example 5. The same tar at the same flow rate as in example 1 was heated under the same conditions and sent to the same reactor as in example 3. Water vapor was supplied to the tubular reactor, the flow rate of which amounted to 5000 kg / h The average speed of the products in the reactor was 14.0 m / s, the reaction time was 10.9 s. The duration of the continuous operation of the installation until it stops to clean the reactor from coke is 12 months. The duration of coke removal from the reactor is 2 days. During the year 1 cleaning was carried out. The increase in the duration of the installation compared to the prototype (example 2) is 8 days, the increase in productivity of the installation is 22080 t / year. The degree of decrease in viscosity of the residue is 16.9.

Example 6. The same tar at the same flow rate as in Example 1 was heated under the same conditions and sent to an adiabatic tubular reactor 200 m long. The flow rate of water vapor was 1000 kg / h. The average velocity of the products in the reactor is 10.0 m / s, the reaction time is 20.0 s. The duration of the continuous operation of the installation until it stops to clean the reactor from coke is 12 months. The duration of coke removal from the reactor is 2 days. During the year 1 cleaning was carried out. The increase in the duration of the installation compared with the prototype (example 2) was 8 days, the productivity of the installation increased by 22080 t / year. The degree of decrease in viscosity of the residue is 16.9.

The data in examples 1-6 are summarized in table.

As can be seen from the examples, the proposed method of visbreaking in comparison with the prototype provides an increase in flow velocity (at the outlet of the reactor, the flow velocity is 8.0-14.0 m / s, while in the prototype - 30 m / s), which will reduce the rate of coke deposition on the walls of the reactor. In addition, the time taken to clean the tubular reactor is 2 days, which is much less than the time required to clean the vertical cylindrical reactor according to the prototype (10 days), which was made possible by simplifying the cleaning process (The tubular reactor was cleaned by the traditional steam-air method , while in the prototype method it was necessary to clean the reactor mechanically). At the same time, the productivity of the visbreaking process increased ~ by 22,000 thousand tons.

From the examples it is seen that the proposed visbreaking process due to the uniformity of the flow within the cross section of the tubular reactor proceeds more intensively, due to which the required visbreaking depth is achieved in less time: in the prototype method (example No. 2), the reaction time in the reactor is 75 seconds, and in the proposed method is from 11 to 20 seconds. This results in a material balance close to the prototype. The latter is also evidenced by the coefficient of viscosity reduction (14 for the prototype and 12-16 for the proposed method). The degree of viscosity reduction is one of the main indicators of the effectiveness of the visbreaking process and is determined by the ratio of the viscosity of the feedstock and visbreaking residue. The higher this indicator, the more efficient the process. However, the desire to achieve the highest possible values of the viscosity reduction index leads to negative consequences, in particular, to coking of apparatuses, reduction of overhaul runs, and increase in the duration of cleaning operations.

In addition, the proposed method provides a predetermined depth of visbreaking by changing the residence time of the reaction products in the reactor by controlling the flow of the transporting agent (examples 4-5).

Table
The main structural and technological indicators of visbreaking processes No. p / p The name of indicators Examples No. 1 analogue (without reactor) 2 prototype 3 offers. cn 4 offers. cn 5 offers. cn 6 offers. cn one The diameter of the reactor, mm - 1810 402 402 402 402 2 The length of the reactor, m - fifteen 150 150 150 200 3 The ratio of reactor length to diameter - 8.3 373 373 373 498 four The reaction volume of the reactor, m ³ - 38 19 19 19 25 5 Raw material consumption, kg / h 115,000 115,000 115,000 115,000 115,000 115,000 6 Consumption of a transporting agent (water vapor), kg / h 1000 0 0 1000 5000 1000 7 The temperature at the outlet of the furnace coil and at the inlet to the reactor, ° C 485 450 450 450 450 450 8 Output flow rate, m / s thirty 0.2 8.0 9.0 fourteen 10.0 9 The duration of the reaction in the reactor, s - 75 19 17 eleven 20,0 10 The yield of products,% wt .:
- gas
- gasoline (nk-180 ° С)
- residue (boiler fuel)
3,5
5.2
91.3
3.9
5.8
90.3
4.0
5.9
90.1
3.8
5.5
90.7
3.2
4.7
92.3
4.0
5.9
90.1 eleven Duration of continuous operation until stopping for cleaning, month 3 12 12 12 12 12 12 The duration of one stop for cleaning, days. 2 10 2 2 2 2 13 The number of stops for cleaning, rest / year four one one one one one fourteen The total duration of stops for cleaning, days / year 8 10 2 2 2 2 fifteen The increase in the duration of the visbreaking reactor compared with the prototype, days / year 2 0 8 8 8 8 16 The increase in the productivity of the visbreaking reactor compared with the prototype (example 2), thousand tons 5520 0 22080 22080 22080 22080 17 The viscosity of the original tar at 80 ° C (° E ₈₀ ^tar ) 270 270 270 270 270 270 eighteen Viscosity of visbreaking residue at 80 ° C (° E ₈₀ ^ost ) twenty fourteen 12 fourteen 16 12 19 The degree of viscosity reduction, ° E ₈₀ ^grades / ° E ₈₀ ^ost 13.5 19,2 22.5 19,2 16.9 22.5

Claims (2)

1. A method of visbreaking a heavy oil residue, including heating a heavy oil residue to a temperature of visbreaking, holding the visbreaking products in an adiabatic reactor to produce gas, gasoline fractions and a visbreaking residue, characterized in that the reactor is tubular with a tubular reactor length to diameter of more than 200. 2. The method according to claim 1, characterized in that at the inlet of the reactor serves a transporting agent, which is used as water vapor or inert gas.