CN112410069B - A kind of catalytic cracking crude gasoline hydrorefining process - Google Patents

Abstract

The invention discloses a catalytic cracking crude gasoline hydrotreating process. The original catalytic cracking and catalytically stabilized gasoline hydrotreating process flow is improved as follows: the catalytic crude gasoline is changed from the original feeding into the absorption tower to directly feeding the gasoline Hydrogen refining unit, other processes remain unchanged. In this way, the catalytic absorption stabilization system only processes rich gas and does not process crude gasoline, so the load and energy consumption will be greatly reduced; the ≤C ₄ components brought into hydrogenation with crude gasoline will not affect the hydrogenation operation, and will change with H ₂ S, Acidic components such as NH ₃ are pulled out from the stripping tower together, and the original process is returned to catalytic refining, and the product stabilizes the vapor pressure of gasoline to ensure that a small amount of gasoline that is absorbed and absorbed along with the rich gas continues to be distilled from the bottom of the stabilization tower. After heat exchange, the original process is mixed with crude gasoline for hydrogenation, so the material balance of the combined unit is not changed.

Description

A kind of catalytic cracking crude gasoline hydrorefining process

technical field

The invention belongs to the technical field of petrochemical industry, and particularly relates to a catalytic cracking crude gasoline hydrorefining process.

Background technique

Catalytic cracking is one of the main methods of secondary processing of petroleum fractions. It is a process in which heavy distillate oil undergoes cracking reaction under the action of high temperature and catalyst and is converted into diesel, gasoline and gas. It consists of four parts: reaction regeneration, main fractionation, absorption stabilization and flue gas energy recovery. Its absorption and stabilization function is to convert the rich gas and crude gasoline from the main fractionation tower into qualified products, including the rich gas compressor, condensing oil tank, absorption tower, reabsorption tower, desorption tower and stabilization tower. . Among them, the function of the reabsorption tower is to use diesel secondary adsorption to absorb the top gas of the tower to obtain a product dry gas with a content of _≥C3 components ≤3%mol; the function of the stabilization tower is to rectify the deethane from the bottom of the desorption tower. Gasoline, to obtain a liquid hydrocarbon (liquefied petroleum gas, LPG) product with a _C5 content of ≤1% mol at the top of the column, and a stable gasoline product with qualified vapor pressure at the bottom of the column.

Stabilized gasoline is the main product of catalytic cracking. It is reported that most of the gasoline in the country is catalytic cracking stabilized gasoline. However, because it is rich in sulfur, nitrogen, olefins, aromatic hydrocarbons, etc., it cannot be directly used as a product, and it needs hydrorefining. Therefore, the conventional process is to send the stable gasoline from the catalytic cracking unit to the hydrorefining unit. Under the action of a certain temperature and catalyst, the sulfur, nitrogen and other impurities are removed by the fixed bed hydrogenation reactor, and the olefin and aromatic content are qualified. . Subsequent reaction to generate oil into the stripping tower (also known as stabilization tower), after removing the acid components and ≤C ₄ fractions formed by the hydrogenation process such as H ₂ S and NH ₃ , it is sent to the fractionation unit to obtain light and heavy gasoline. The question arises, since the hydrotreating unit also has the function of removing ≤C ₄ fractions, can it directly process crude gasoline? In this way, the upstream catalytic absorption stabilization system will only deal with rich gas, and the load and energy consumption will be greatly reduced. The present invention is proposed based on this consideration.

SUMMARY OF THE INVENTION

In order to solve the shortcomings of the existing catalytic cracking unit and catalytically stabilized gasoline hydrotreating unit due to the isolated design, resulting in repeated fractionation of stabilized gasoline, large processing capacity and high energy consumption of the absorption stabilization system, the present invention provides a catalytic cracking crude gasoline hydrogenation. The core of the refining process is to integrate gasoline stabilization and directly send catalytic crude gasoline to hydrorefining.

The object of the present invention is achieved through the following technical solutions:

A catalytic cracking crude gasoline hydrorefining process, the following improvements are made in the process flow of the original catalytic cracking unit and the gasoline hydrorefining unit:

The crude gasoline at the top of the main fractionation tower is changed from the original into the absorption tower to directly into the catalytic gasoline hydrotreating unit, and other pipeline processes remain unchanged.

Further, the flow process of described a kind of catalytic cracking crude gasoline hydrorefining process is as follows:

The reaction oil and gas from the reaction unit enters the lower part of the herringbone baffle of the main fractionation tower 1, and contacts the circulating oil slurry flowing down from the top of the herringbone baffle from bottom to top. After being washed and desuperheated, it enters the fractionation part. Refined oil, diesel oil, crude gasoline and gas are obtained, and the excess heat is taken away by the cooling system at the top of the tower, the top circulation return, a middle-stage return and oil slurry circulation return;

The gas at the top of the main fractionation tower 1 is cooled to about 40 ° C through the oil and gas-hot water heat exchanger 2, air cooler 3, and circulating water cooler 4 at the top of the fractionation tower, and enters the gas-liquid separation tank 5, where non-condensable gas and condensation are separated. Crude gasoline, non-condensable gas is compressed into the rich gas compressor 6/1, mixed with the top gas of the stripping tower 38, cooled by the circulating water cooler 10 at the compressor's primary outlet, and sent to the compressor's primary outlet for gas-liquid separation Tank 11 separates non-condensable steam and tank bottom oil. The bottom oil of the absorption tower 17 pumped by the oil pump 18 and the bottom oil of the first stage outlet of the compressor pumped by the oil pump 12 are mixed with the bottom oil of the gas-liquid separation tank 11. After cooling by the circulating water cooler 14, the 40 ℃ condensate oil tank 15; the condensed crude gasoline is pressurized by the crude gasoline pump 7 and then sent to the reactant-raw material heat exchanger 44 of the gasoline hydrorefining unit;

The side-line diesel oil flows into the diesel stripping tower 8 from the 16th floor of the main fractionation tower 1, is extracted by the lean diesel oil pump 9 after stripping, and then is divided into product diesel oil and lean diesel oil, and the lean diesel oil is further sent to the top of the reabsorption tower 36 after cooling;

The operating pressure of the absorption tower 17 is 1.2MPag, the gas from the condensed oil tank 15 enters the lower part, and the stabilized gasoline as a supplementary absorbent from the stabilization tower 24 enters the top, and they are in countercurrent contact to complete mass transfer and heat transfer, and intermediate circulating water The cooler helps to achieve heat balance; the lean gas from the top of the absorption tower 17 is sent to the bottom of the absorption tower 36, and is in countercurrent contact with the lean diesel oil to absorb the _≥C3 components carried by it, and the product dry gas is discharged from the top of the tower. The bottom rich diesel is sent to the main fractionation tower 1;

After the condensed oil comes out of the condensed oil tank 15 and is pressurized by the feed pump 16 of the desorption tower, it passes through the condensed oil-stabilized gasoline heat exchanger 32 and exchanges heat with the stabilized gasoline to 50 °C and enters the upper part of the desorption tower 19, and the bottom of the desorption tower is heated. The reboilers 20 and 21 are heated by reflux and 1.0MPa steam in the first fractionation tower respectively, the reboiler 30 in the middle of the desorption tower is heated by the stabilized gasoline, and the deethanized gasoline at the bottom of the desorption tower 19 is fed through the stabilization tower. After the pump 22 is pressurized, the deethanized gasoline-stabilized gasoline heat exchanger 23 exchanges heat with the stabilized gasoline and then enters the stabilization tower 24. The reboiler 29 at the bottom of the stabilization tower is refluxed for heat supply in the second main fractionation tower, and LPG is light. The components are distilled from the top of the tower, condensed and cooled to 40°C by the stabilizer cooler 25 and entered into the gas-liquid separation tank 26 at the top of the stabilized tower. A part of the liquefied gas is pressurized by the reflux pump 27 at the top of the stabilized tower as a cold reflux, and a part of the liquefied gas is passed through the liquefied gas. The product pump 28 is pressurized and sent as a product outlet device; the stabilized gasoline at the bottom of the tower is sequentially passed through the deethane gasoline-stabilized gasoline heat exchanger 23, the desorption tower intermediate reboiler 30, the deoxygenated water heat exchanger 31, and the condensed oil- The stabilized gasoline heat exchanger 32, the air cooler 33, and the circulating water cooler 34 are cooled to 40°C, are boosted by the supplementary absorbent pump 35 and then divided into two paths, one path is sent to the absorption tower 17 as the supplementary absorbent, and the other path is used as the raw material for stabilization The gasoline is sent to the gasoline hydrotreating unit;

The raw material stabilized gasoline, the crude gasoline from the autonomous fractionation tower 1 and the external hydrogen are mixed, and then enter the reactant-raw material heat exchanger 44 and the hydrorefining raw material heating furnace 43 in turn, and enter the pre-hydrogenation reactor 37 after the heat exchange and temperature rise, and the generated The reactant enters the stripping tower 38 after heat exchange by the reactant-raw material heat exchanger 44, and the light components are distilled from the top of the tower, and after condensing and cooling by the stripping tower cooler 39, they enter the gas-liquid separator 40 at the top of the stripping tower. , the non-condensable gas and the liquid are separated, the non-condensable gas is directly sent to the first-stage outlet circulating water cooler 10 of the compressor through the pipeline, the liquid is pressurized by the reflux pump 41 at the top of the stripping tower as a cold reflux, and refined gasoline is produced at the bottom of the tower, The stripper bottom reboiler 42 is heated by 1.0 MPa steam.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) Crude gasoline is directly sent for hydrorefining, so the catalytic absorption stabilization system does not process crude gasoline, but only processes rich gas, and the processing capacity, energy consumption and energy consumption quality will be greatly reduced;

(2) The ≤C ₄ components brought into the hydrorefining unit with the crude gasoline will not affect the hydrogenation operation. They will be pulled out from the top of the stripping tower together with the acidic components such as H ₂ S and NH ₃ to remove the original The process is returned to catalytic refining, thus ensuring the quality of the product to stabilize the gasoline; and the quality of the product LPG continues to be guaranteed by the catalytic stabilization tower;

(3) A small amount of gasoline that is absorbed and stabilized with the rich gas continues to be distilled from the bottom of the stable tower, and after heat exchange, it is mixed with crude gasoline and sent to hydrogenation through the original process, so the material balance of the combined device is not changed;

(4) Most of the functions of the catalytic stabilization tower to produce stable gasoline are cleverly transferred to the stripper of the hydrogenation unit by the crude gasoline direct refining process, thereby avoiding the double distillation of gasoline, which is the key reason for the low energy consumption of the combined unit. It has significant innovative significance.

Description of drawings

Fig. 1 is the process flow diagram of the comparative example of the present invention (existing 4.8 million tons/year catalytic cracking unit and 2 million tons/year gasoline hydrotreating unit).

Fig. 2 is the process flow diagram of the embodiment of the present invention, and the numbering in the figure is explained as follows: 1-main fractionation tower; 2-fractionation tower top oil and gas-hot water heat exchanger; 3-air cooler; 4-circulating water cooler; 5-gas-liquid separation tank; 6-rich gas compressor (6/1 and 6/2); 7-crude gasoline pump; 8-diesel stripper; 9-lean diesel pump; 10-compressor first-stage outlet circulation Water cooler; 11- compressor first-stage outlet gas-liquid separation tank; 12- tank bottom oil pump; 13- air cooler; 14- circulating water cooler; 15- condensing oil tank; 16- desorption tower feed pump; 17- Absorption tower; 18- Suction bottom oil pump; 19- Desorption tower; 20- Desorption tower bottom reboiler; 21- Desorption tower bottom reboiler; 22- Stabilizer tower feed pump; 23- Deethanized gasoline - stabilized gasoline heat exchanger; 24- stabilized tower; 25- stabilized tower cooler; 26- stabilized tower top gas-liquid separation tank; 27- stabilized tower top reflux pump; 28- liquefied gas product pump; 29- stabilized tower bottom Reboiler; 30-Intermediate Reboiler of Desorption Tower; 31-Deoxygenated Water Heat Exchanger; 32-Condensed Oil-Stabilized Gasoline Heat Exchanger; 33-Air Cooler; 34-Circulating Water Cooler; 35-Supplementary Absorbent pump; 36-reabsorption tower; 37-pre-hydrogenation reactor; 38-stripper; 39-stripper cooler; 40-stripper overhead gas-liquid separation tank; 41-stripper overhead reflux pump; 42- stripping tower bottom reboiler; 43- hydrorefining raw material heating furnace; 44- reactant-raw material heat exchanger.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

If the specific conditions are not indicated in the examples of the present invention, the conventional conditions or the conditions suggested by the manufacturer are used. The raw materials, reagents, etc., which are not specified by the manufacturer, are all conventional products that can be purchased from the market.

Comparative ratio

This comparative example is an existing catalytic cracking fractionation and absorption stabilization system, the process flow diagram of which is shown in Figure 1. The specific process is as follows:

The reaction oil and gas from the reaction unit enters the lower part of the herringbone baffle of the main fractionation tower 1, and from bottom to top, it is in countercurrent contact with the circulating oil slurry at 275°C flowing down from the top of the herringbone baffle. Fractional distillation is used to obtain back refining oil, diesel oil, crude gasoline and gas in turn, and the excess heat is taken away by the cooling system at the top of the tower, the circulating reflux at the top, the reflux in a middle section and the circulating reflux of the oil slurry;

The gas at the top of the main fractionation tower 1 is cooled to 40 ° C through the oil and gas-hot water heat exchanger 2, air cooler 3, and circulating water cooler 4 at the top of the fractionation tower, and enters the gas-liquid separation tank 5, where non-condensable gas and condensed crude gas are separated. Gasoline, non-condensable gas is fed into the rich gas compressor 6/1, mixed with the top gas of the stripping tower 38, cooled by the compressor first-stage outlet circulating water cooler 10, and sent to the compressor first-stage outlet gas-liquid separation tank 11. The non-condensable steam and tank bottom oil are discharged. The non-condensable steam is compressed to 1.3MPag by the rich gas compressor 6/2, and then mixed with the top air of the desorption tower 19, cooled by the air cooler 13, and pumped by the suction bottom oil pump 18. The bottom oil of the absorption tower 17 and the bottom oil pumped by the tank bottom oil pump 12 are mixed with the first-stage outlet gas-liquid separation tank of the compressor 11, and the tank bottom oil is mixed and cooled by the circulating water cooler 14, and then enters the condensed oil tank 15 at 40°C to condense the crude gasoline. Then it is sent to the absorption tower 17 after being pressurized by the crude gasoline pump 7;

The side-line diesel oil flows into the diesel stripping tower 8 from the 16th floor of the main fractionation tower 1, is extracted by the lean diesel oil pump 9 after stripping, and then is divided into product diesel oil and lean diesel oil, and the lean diesel oil is further sent to the top of the reabsorption tower 36 after cooling;

The operating pressure of the absorption tower 17 is 1.2MPag, the gas from the condensed oil tank 15 enters the lower part, and the stabilized gasoline as a supplementary absorbent from the stabilization tower enters the top, and they are in countercurrent contact to complete the mass transfer and heat transfer, and the intermediate circulating water is cooled The depleted gas from the top of the absorption tower 17 is sent to the bottom of the reabsorption tower 36, and is in countercurrent contact with the lean diesel oil to absorb the _≥C3 components carried by it, the product dry gas is discharged from the top of the tower, and the bottom of the tower is discharged. The rich diesel oil is sent to the main fractionation tower 1;

The condensed oil comes out of the condensed oil tank 15 and is pressurized by the feed pump 16 of the desorption tower, then passes through the condensed oil-stabilized gasoline heat exchanger 32 and exchanges heat with the stabilized gasoline to 50 °C and enters the upper part of the desorption tower 19, and the bottom of the desorption tower is heated. The reboilers 20 and 21 are heated by reflux and 1.0MPa steam in the first fractionation tower respectively, the reboiler 30 in the middle of the desorption tower is heated by the stabilized gasoline, and the deethanized gasoline at the bottom of the desorption tower 19 is fed through the stabilization tower. After the pump 22 increases the pressure, the deethane gasoline-stabilized gasoline heat exchanger 23 exchanges heat with the stabilized gasoline and then enters the stabilization tower 24. The reboiler 29 at the bottom of the stabilization tower is supplied by reflux in the second main splitter, and the LPG is light. The components are distilled from the top of the tower, condensed and cooled to 40°C by the stabilizer cooler 25 and entered into the gas-liquid separation tank 26 at the top of the stabilized tower. A part of the liquefied gas is pressurized by the reflux pump 27 at the top of the stabilized tower as a cold reflux, and a part of the liquefied gas is passed through the liquefied gas. The product pump 28 is pressurized and sent as a product discharge device; the stabilized gasoline at the bottom of the tower is sequentially passed through the deethane gasoline-stabilized gasoline heat exchanger 23, the desorption tower intermediate reboiler 30, the deoxygenated water heat exchanger 31, and the condensed oil- The stabilized gasoline heat exchanger 32, the air cooler 33, and the circulating water cooler 34 are cooled to 40°C, boosted by the supplementary absorbent pump 35 and then divided into two paths, one is sent to the absorption tower 17 as supplementary absorbent, and the other is used as a raw material for stabilization The gasoline is sent to the gasoline hydrogenation unit;

The raw material stabilized gasoline is mixed with external hydrogen, and enters the reactant-raw material heat exchanger 44 and the hydrorefining raw material heating furnace 43 in turn. After heat exchange, the device 44 enters the stripping tower 38, and the light components are distilled from the top of the tower, and after condensing and cooling by the stripping tower cooler 39, they enter the gas-liquid separating tank 40 at the top of the stripping tower, and separate non-condensable gas and liquid, The non-condensable gas is directly sent to the first-stage outlet circulating water cooler 10 of the compressor through the pipeline, and the liquid is pressurized by the reflux pump 41 at the top of the stripping column as a cold reflux, and gasoline is generated at the bottom of the column, and the reboiler 42 at the bottom of the stripping column is composed of 1.0MPa steam heating.

Example

In the present embodiment, the combined energy-saving process flow of a catalytic cracking device and a gasoline hydrogenation device is improved as follows on the original catalytic cracking device and the technological process:

The crude gasoline at the top of the main fractionation tower is directly sent to the gasoline hydrogenation unit from the original absorption tower, and the other pipeline processes remain unchanged.

Its process flow chart is shown in Figure 2, and the specific process flow is as follows:

The reaction oil and gas from the reaction unit enters the lower part of the herringbone baffle of the main fractionation tower 1, and contacts the circulating oil slurry flowing down from the top of the herringbone baffle from bottom to top. After being washed and desuperheated, it enters the fractionation part. Refined oil, diesel oil, crude gasoline and gas are obtained, and the excess heat is taken away by the cooling system at the top of the tower, the top circulation return, a middle-stage return and oil slurry circulation return;

The gas at the top of the main fractionation tower 1 is cooled to about 40 ° C through the oil and gas-hot water heat exchanger 2, air cooler 3, and circulating water cooler 4 at the top of the fractionation tower, and enters the gas-liquid separation tank 5, where non-condensable gas and condensation are separated. Crude gasoline, non-condensable gas is compressed into the rich gas compressor 6/1, mixed with the top gas of the stripping tower 38, cooled by the circulating water cooler 10 at the compressor's primary outlet, and sent to the compressor's primary outlet for gas-liquid separation Tank 11 separates non-condensable steam and tank bottom oil. The bottom oil of the absorption tower 17 pumped by the oil pump 18 and the bottom oil of the first stage outlet of the compressor pumped by the oil pump 12 are mixed with the bottom oil of the gas-liquid separation tank 11. After cooling by the circulating water cooler 14, the 40 ℃ condensate oil tank 15; the condensed crude gasoline is pressurized by the crude gasoline pump 7 and then sent to the reactant-raw material heat exchanger 44 of the gasoline hydrorefining unit;

The side-line diesel oil flows into the diesel stripping tower 8 from the 16th floor of the main fractionation tower 1, is extracted by the lean diesel oil pump 9 after stripping, and then is divided into product diesel oil and lean diesel oil, and the lean diesel oil is further sent to the top of the reabsorption tower 36 after cooling;

The operating pressure of the absorption tower 17 is 1.2MPag, the gas from the condensed oil tank 15 enters the lower part, and the stabilized gasoline as a supplementary absorbent from the stabilization tower 24 enters the top, and they are in countercurrent contact to complete mass transfer and heat transfer, and intermediate water circulation The cooler helps to achieve heat balance; the lean gas from the top of the absorption tower 17 is sent to the bottom of the re-absorption tower 36, and is in countercurrent contact with the lean diesel oil to absorb the _≥C3 components carried by it, and the product dry gas is discharged from the top of the tower. The bottom rich diesel is sent to the main fractionation tower 1;

After the condensed oil comes out of the condensed oil tank 15 and is pressurized by the feed pump 16 of the desorption tower, it passes through the condensed oil-stabilized gasoline heat exchanger 32 and exchanges heat with the stabilized gasoline to 50 °C and enters the upper part of the desorption tower 19, and the bottom of the desorption tower is heated. The reboilers 20 and 21 are heated by reflux and 1.0MPa steam in the first fractionation tower respectively, the reboiler 30 in the middle of the desorption tower is heated by the stabilized gasoline, and the deethanized gasoline at the bottom of the desorption tower 19 is fed through the stabilization tower. After the pump 22 is pressurized, the deethanized gasoline-stabilized gasoline heat exchanger 23 exchanges heat with the stabilized gasoline and then enters the stabilization tower 24. The reboiler 29 at the bottom of the stabilization tower is refluxed for heat supply in the second main fractionation tower, and LPG is light. The components are distilled from the top of the tower, condensed and cooled to 40°C by the stabilizer cooler 25 and entered into the gas-liquid separation tank 26 at the top of the stabilized tower. A part of the liquefied gas is pressurized by the reflux pump 27 at the top of the stabilized tower as a cold reflux, and a part of the liquefied gas is passed through the liquefied gas. The product pump 28 is pressurized and sent as a product outlet device; the stabilized gasoline at the bottom of the tower is sequentially passed through the deethane gasoline-stabilized gasoline heat exchanger 23, the desorption tower intermediate reboiler 30, the deoxygenated water heat exchanger 31, and the condensed oil- The stabilized gasoline heat exchanger 32, the air cooler 33, and the circulating water cooler 34 are cooled to 40°C, are boosted by the supplementary absorbent pump 35 and then divided into two paths, one path is sent to the absorption tower 17 as the supplementary absorbent, and the other path is used as the raw material for stabilization The gasoline is sent to the gasoline hydrotreating unit;

The raw material stabilized gasoline, the crude gasoline from the autonomous fractionation tower 1 and the external hydrogen are mixed, and then enter the reactant-raw material heat exchanger 44 and the hydrorefining raw material heating furnace 43 in turn, and enter the pre-hydrogenation reactor 37 after the heat exchange and temperature rise, and the generated The reactant enters the stripping tower 38 after heat exchange by the reactant-raw material heat exchanger 44, and the light components are distilled from the top of the tower, and after condensing and cooling by the stripping tower cooler 39, they enter the gas-liquid separator 40 at the top of the stripping tower. , the non-condensable gas and the liquid are separated, the non-condensable gas is directly sent to the first-stage outlet circulating water cooler 10 of the compressor through the pipeline, the liquid is pressurized by the reflux pump 41 at the top of the stripping tower as a cold reflux, and refined gasoline is produced at the bottom of the tower, The stripper bottom reboiler 42 is heated by 1.0 MPa steam.

The following takes a 4.8 million ton/year catalytic cracking unit and a 2 million ton/year gasoline hydrogenation unit as examples to illustrate the main operating conditions of the comparative example and the embodiment, and the quality indicators of each product are controlled to remain unchanged in the comparative example and the embodiment.

Table 1 shows the operation of the rich gas compressor of the comparative example and the embodiment.

Table 1 Operation of the rich gas compressor of the comparative example and the embodiment

*Based on isentropic compression efficiency of 75%.

Table 2 is the rich gas cooling duty for the Comparative Examples and Examples.

Table 2 Comparative example and example rich gas cooling load

Table 3 is the supplemental absorbent flow rate for the Comparative Examples and Examples.

Table 3 Comparative Examples and Examples Supplementary Absorbent Flow

Table 4 is the operation of the desorption tower reboiler of the comparative example and the embodiment.

Table 4 comparative example and embodiment desorption tower reboiler operation situation

Table 5 is the energy consumption situation of the stabilization tower in the comparative example and the embodiment.

Table 5 Comparative Examples and Examples of Stabilizing Tower Energy Consumption Operation

Table 6 is the operation of the heat exchanger of the gasoline hydrogenation unit of the comparative example and the embodiment.

Table 6 Comparative Examples and Examples Gasoline Hydrogenation Unit Heat Exchanger Operation

Table 7 shows the stripper operation of the comparative examples and examples.

Table 7 comparative example and embodiment stripping tower energy consumption operation situation

As can be seen from Table 1 to Table 7, compared to the comparative example, the embodiment:

1. The power consumption of the rich gas compressor increased by 194.0kw, an increase of 4.0%, and the steam consumption of the 3.5MPa driven turbine increased by 0.4t/h

2. The cooling load of rich gas increases by 196.9×10 ⁴ kcal/h, an increase of 13.6%, and the circulating water consumption is reduced by 328.2t/h according to the temperature drop of circulating water by 6℃;

3. Supplementary absorbent increased by 53t/h;

4. The reboiling load of the desorption tower is reduced by 541.5×10 ⁴ kcal/h (10.2t/h of 1.0MPa steam), and the decrease rate is 32.9%; The saturation temperature is 148°C) as a heat source;

5. The reboiling load of the stabilization tower is reduced by 340.4×10 ⁴ kcal/h (6.4t/h of steam at 3.5MPa), and the reduction rate is 15.2%; 1.0MPa steam (saturation temperature of 184.1℃) is used as heat source; the cooling load of the stabilization tower is reduced by 488.6×10 ⁴ kcal/h, a decrease of 20.1%, and the circulating water temperature is reduced by 6℃, and the circulating water consumption is 814.3t/h;

6. The load of the heating furnace for hydrorefining raw materials is increased by 152.4×10 ⁴ kcal/h (calculated according to the furnace efficiency of 90%, and the standard fuel oil consumption is 0.17t/h), an increase of 15.3%;

7. The reboiling load of the stripper increased by 393.4×10 ⁴ kcal/h (equivalent to 1.0MPa steam was 7.4t/h), a decrease of 57.2%; the cooling load of the stripper increased by 448×10 ⁴ kcal/h, an increase of 68.5%, According to the temperature drop of circulating water 6℃, the consumption of circulating water is 746.7t/h;

The total example is based on the unit price of 3.5MPa steam 300 yuan/t, the unit price of 1.0MPa steam 250 yuan/t, the unit price of 0.35MPa steam 200 yuan/t, the standard fuel oil 3000 yuan/t, the circulating water treatment cost 0.2 yuan/t, the installation year Calculated after 8400 hours of operation, the example reduces the energy consumption cost by 33.031 million yuan per year compared with the comparative example.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (1)

1. a catalytic cracking crude gasoline hydrorefining process is characterized in that, on the technological process of original catalytic cracking unit and gasoline hydrorefining unit, the following improvements are made: The crude gasoline at the top of the main fractionation tower was changed from the original into the absorption tower to directly into the catalytic gasoline hydrotreating unit, and other pipeline processes remained unchanged; The technical process of the catalytic cracking unit and the gasoline hydrotreating unit is as follows: The reacted oil and gas from the reaction unit enters the lower part of the herringbone baffle of the main fractionation tower (1), and contacts the circulating oil slurry flowing down from the top of the herringbone baffle from bottom to top. Fractional distillation is used to obtain back refining oil, diesel oil, crude gasoline and gas in turn, and the excess heat is taken away by the cooling system at the top of the tower, the circulating reflux at the top, the reflux in a middle section and the circulating reflux of the oil slurry; The gas at the top of the main fractionation tower (1) is cooled to 40°C through the oil and gas-hot water heat exchanger (2), air cooler (3), and circulating water cooler (4) at the top of the fractionation tower, and enters the gas-liquid separation tank (5). ), separate the non-condensable gas and the condensed crude gasoline, the non-condensable gas is compressed into the rich gas compressor (6/1), mixed with the top gas of the stripper (38), and passed through the first-stage outlet circulating water cooler of the compressor (10) Cool and send to the first-stage outlet gas-liquid separation tank (11) of the compressor to separate the non-condensable steam and the bottom oil of the tank. The top gas of the tower (19) is mixed, cooled by the air cooler (13), and the compressor pumped by the absorption tower (17) bottom oil and the tank bottom oil pump (12) pumped by the suction bottom oil pump (18). The first-stage outlet gas-liquid separation tank (11) is mixed with the bottom oil, cooled by the circulating water cooler (14), and then fed into the condensed oil tank (15) at 40°C; the condensed crude gasoline is pressurized by the crude gasoline pump (7) The reactant-raw heat exchanger (44) is then sent to the gasoline hydrotreating unit; The side-line diesel flows from the 16th layer of the main fractionation tower (1) into the diesel stripper (8), and after stripping, it is extracted by the lean diesel pump (9), and then divided into product diesel and lean diesel, and the lean diesel is further cooled and sent to the top of the reabsorption tower (36); The operating pressure of the absorption tower (17) is 1.2MPaG, the gas from the condensing oil tank (15) enters the lower part, and the stabilized gasoline from the stabilization tower (24) as a supplementary absorbent enters the top, and they are in countercurrent contact to complete the mass transfer and Heat transfer, and the intermediate circulating water cooler helps to achieve heat balance; the lean gas from the top of the absorption tower (17) is sent to the bottom of the reabsorption tower (36), and is in countercurrent contact with the lean diesel oil to absorb the _≥C3 components carried by it , the product dry gas is discharged from the top of the tower, and the rich diesel oil at the bottom of the tower is sent to the main fractionation tower (1); The condensed oil comes out from the condensed oil tank (15) and is pressurized by the feed pump (16) of the desorption tower, then passes through the condensed oil-stabilized gasoline heat exchanger (32) and exchanges heat with the stabilized gasoline to 50°C and enters the desorption tower ( 19) In the upper part, the reboilers (20) and (21) at the bottom of the desorption tower are heated by reflux and 1.0MPa steam respectively in the first middle of the main fractionation tower, and the middle reboiler (30) of the desorption tower is heated by the stabilized gasoline for secondary heating, The de-ethanized gasoline at the bottom of the desorber (19) is boosted by the stabilizer feed pump (22), and then passes through the deethanizer-stabilized gasoline heat exchanger (23) to exchange heat with the stabilized gasoline and then enters the stabilization tower (24). ), the reboiler (29) at the bottom of the stabilizing tower is heated by reflux in the second main fractionation tower, and the LPG light components are distilled from the top of the tower, condensed and cooled to 40 °C by the stabilizing tower cooler (25), and enter the top gas of the stabilizing tower In the liquid separation tank (26), a part of the liquefied gas is pressurized by the stabilizing tower top reflux pump (27) as a cold reflux, and a part is pressurized by the liquefied gas product pump (28) as a product sending device; the stabilized gasoline at the bottom of the tower is sequentially deethylenated Alkane gasoline-stabilized gasoline heat exchanger (23), desorption tower intermediate reboiler (30), deoxygenated water heat exchanger (31), condensed oil-stabilized gasoline heat exchanger (32), air cooler (33) ), the circulating water cooler (34) is cooled to 40°C, the pressure is boosted by the supplementary absorbent pump (35) and then divided into two paths, one path is sent to the absorption tower (17) as a supplementary absorbent, and the other path is sent to the gasoline as a raw material stabilized gasoline Hydrotreating unit; The raw material stabilized gasoline, the crude gasoline from the independent fractionation tower (1) and the external hydrogen are mixed, and then enter the reactant-raw material heat exchanger (44) and the hydrorefining raw material heating furnace (43) in turn, and then enter the pre-hydrogenation after heat exchange and temperature rise. In the reactor (37), the generated reactant enters the stripping column (38) after heat exchange by the reactant-raw material heat exchanger (44), and the light components are distilled from the top of the column and pass through the stripping column cooler (39) After condensing and cooling, it enters the gas-liquid separation tank (40) at the top of the stripping tower to separate non-condensable gas and liquid. The top reflux pump (41) is pressurized and used as a cold reflux, the bottom of the column produces refined gasoline, and the reboiler (42) at the bottom of the stripping column is heated by 1.0MPa steam.

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