CN111019687A - Finished oil fractionation system - Google Patents

Abstract

The invention discloses a finished oil fractionation system, which relates to the field of finished oil fractionation and comprises the following components: a raw material area: used for storing raw materials; a gasoline feed pump: used for conveying the raw materials; a heat exchanger: carrying out heat exchange heating on the product; a gasoline prefractionator: heating and distilling the raw materials, and controlling the temperature of the top and the bottom of the tower to make the gas phase at the top of the tower pass through an air-cooled heat exchanger, a cooler and a reflux tank; a reflux pump: conveying a part of naphtha to a gasoline prefractionator, and conveying a part of naphtha to a naphtha tank area; low-pressure gas buffer tank: for receiving naphtha when the reflux drum is not vented. The invention can convert the oil product with higher sulfur content into the oil product with lower sulfur content, thereby reducing the storage space of the low-quality oil product, and meanwhile, the cost of directly purchasing the oil product with high sulfur content can be reduced by purchasing the secondary oil product with higher sulfur content at low price and then performing secondary processing, thereby reducing the purchase cost.

Description

Finished oil fractionation system

Technical Field

The invention relates to the field of finished oil fractionation, in particular to a finished oil fractionation system.

Background

Petroleum Fractionation (The Fractionation of The Petroleum) is a method of separating several mixtures of different boiling points in Petroleum, which belongs to physical changes, Petroleum (Petroleum) is a mixture composed of over 8000 kinds of hydrocarbons (and a small amount of sulfur compounds) with different molecular sizes, Petroleum must be processed before use to prepare Petroleum products suitable for various purposes, and The common processing method is Fractionation (Fractionation) which separates The hydrocarbons in Petroleum by using The principles of different molecular sizes and different boiling points, and then improves The value of The products by chemical processing.

And the oil gas is increased from the fifth state to the sixth state along with the national adjustment of the oil product, and the fifth state oil stored in a large amount in an oil depot must be used after being fractionated, so that the fifth state oil reaches the national standard and is continuously utilized.

Disclosure of Invention

The invention aims to: in order to solve the problems that the stock quantity of the domestic five-product oil is huge, the fractionation speed is slow and the safety performance cannot be further improved, a product oil fractionation system is provided.

In order to achieve the purpose, the invention provides the following technical scheme: a finished oil fractionation system, comprising:

a raw material area: used for storing raw materials;

a gasoline feed pump: used for conveying the raw materials;

a heat exchanger: carrying out heat exchange heating on the product;

a gasoline prefractionator: heating and distilling the raw materials, and controlling the temperature of the top and the bottom of the tower to make the gas phase at the top of the tower pass through an air-cooled heat exchanger, a cooler and a reflux tank;

a reflux pump: conveying a part of naphtha to a gasoline prefractionator, and conveying a part of naphtha to a naphtha tank area;

low-pressure gas buffer tank: for receiving naphtha when the reflux drum is not aerated;

a gasoline fractionating tower: the device is used for receiving the tower bottom of the gasoline prefractionator and distilling the tower bottom oil to form a new tower top gas phase and the tower bottom gasoline, wherein the tower top gas phase exchanges heat with the raw material through a top oil-gas heat exchanger and enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, part of naphtha in the reflux tank is pumped back through a tower top reflux pump to control the tower top temperature, and the other part of naphtha is sent to a gasoline tank area;

a tower bottom pump: and the bottom oil is conveyed to a heat exchanger, qualified gasoline is conveyed to a gasoline storage tank, and unqualified gasoline is conveyed to a hydrogenation process.

Preferably, the raw material in the raw material area needs to be subjected to heat exchange through a heat exchanger for three times before entering a gasoline prefractionator, and the heat exchange is carried out until the temperature is 60-70 ℃.

Preferably, the gasoline pre-fractionation tower utilizes a reboiler at the bottom end thereof to distill and heat the raw material, the temperature of the bottom of the gasoline pre-fractionation tower is 120-130 ℃, and the temperature of the top of the gasoline pre-fractionation tower is 102 ℃.

Preferably, the cooler pair cools the gas phase at the top of the gasoline pre-distillation tower to 35 ℃, and naphtha fed back to the gasoline pre-distillation tower is used for controlling the temperature at the top of the gasoline pre-distillation tower.

Preferably, the gasoline fractionating tower and the gasoline prefractionator are connected with a conveying pipeline through a vacuum pump.

Preferably, the tower bottom pump needs to exchange heat through the heat exchanger twice when conveying oil products.

Preferably, S of the qualified gasoline is less than 10PPM, S of the unqualified gasoline is more than 10PPM, the carbon dioxide protection layer consists of a hollow iron protection plate and carbon dioxide gas, and the carbon dioxide protection layer is positioned on the outer side of the raw material area.

Preferably, the method comprises the following steps:

the method comprises the following steps: the gasoline feed pump transfers the gasoline in the raw material tank area to a gasoline prefractionator through the heat exchanger for three times of heat exchange;

step two: fractionating gasoline by a reboiler in the gasoline prefractionator to form a top gas phase and bottom oil;

step three: the tower top gas phase exchanges heat through the tower top gas phase through an air cooling heat exchanger, a cooler cools the tower top gas phase to 35 ℃ and then enters a reflux tank, part of naphtha in the tower top reflux tank is pumped back through a reflux pump to control the tower top temperature, and part of naphtha is sent to a naphtha tank area; the non-condensable gas in the reflux tank is controlled by a pressure control valve and then flows to a low-pressure gas buffer tank;

step four: the tower bottom oil is conveyed to a gasoline fractionating tower through a tower bottom pump;

step five: the gasoline fractionating tower is used for carrying out secondary fractionation on the gasoline to form a new tower top gas phase and tower bottom oil in the gasoline fractionating tower;

step six: the gas phase at the top of the tower exchanges heat with the raw material through a tower top oil-gas heat exchanger, and the gas phase at the top of the tower enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, naphtha in the reflux tank reflows through the top of the tower, one part of the naphtha is pumped back to control the temperature at the top of the tower, and the other part of the naphtha is sent to a gasoline;

step seven: and pumping the bottom oil of the gasoline fractionating tower to a heat exchanger through a tower bottom pump for heat exchange, then transferring the bottom oil to a gasoline storage tank after the heat exchange of the heat exchanger, and transferring the qualified national six gasoline to a hydrogenation raw material buffer tank D-105 in a hydrogenation process.

Compared with the prior art, the invention has the beneficial effects that: the invention can convert the oil product with higher sulfur content into the oil product with lower sulfur content, thereby reducing the storage space of the low-quality oil product, and meanwhile, the cost of directly purchasing the oil product with high sulfur content can be reduced by purchasing the secondary oil product with higher sulfur content at low price and then performing secondary processing, thereby reducing the purchase cost; the carbon dioxide protective layer can effectively protect the raw material area and reduce fire accidents, so that the safety performance is further improved and the safety risk is reduced.

Drawings

FIG. 1 is a schematic flow chart of the system of the present invention. .

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a system for fractionating oil comprises:

a raw material area: used for storing raw materials;

a gasoline feed pump: used for conveying the raw materials;

a heat exchanger: carrying out heat exchange heating on the product;

a gasoline prefractionator: heating and distilling the raw materials, and controlling the temperature of the top and the bottom of the tower to make the gas phase at the top of the tower pass through an air-cooled heat exchanger, a cooler and a reflux tank;

a reflux pump: conveying a part of naphtha to a gasoline prefractionator, and conveying a part of naphtha to a naphtha tank area;

low-pressure gas buffer tank: for receiving naphtha when the reflux drum is not aerated;

a gasoline fractionating tower: the device is used for receiving the tower bottom of the gasoline prefractionator and distilling the tower bottom oil to form a new tower top gas phase and the tower bottom gasoline, wherein the tower top gas phase exchanges heat with the raw material through a top oil-gas heat exchanger and enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, part of naphtha in the reflux tank is pumped back through a tower top reflux pump to control the tower top temperature, and the other part of naphtha is sent to a gasoline tank area;

a tower bottom pump: and the bottom oil is conveyed to a heat exchanger, qualified gasoline is conveyed to a gasoline storage tank, and unqualified gasoline is conveyed to a hydrogenation process.

Example 1

As a preferred embodiment of the present invention: the raw material in the raw material area needs to be subjected to heat exchange through a heat exchanger for three times before entering a gasoline prefractionator, and the heat exchange is carried out to 60-70 ℃;

for heating a cryogenic fluid or cooling a high temperature fluid, vaporizing a liquid into a vapor or condensing a vapor into a liquid. The heat exchanger can be a unit device such as a heater, a cooler, a condenser and the like; or may be an integral part of a piece of process equipment, such as a heat exchanger in an ammonia synthesis column. The heat exchanger is an important unit device in chemical production, the tonnage of the heat exchanger accounts for about 20 percent of the whole process equipment or even up to 30 percent according to statistics, the importance of the heat exchanger can be thought of, so the heat exchanger needs to be cleaned periodically, the cleaning of the heat exchanger and other devices becomes an indispensable important link in industrial (such as petroleum, chemical industry, electric power and metallurgy industries) production, the high-pressure water jet cleaning heat exchanger belongs to a physical cleaning method, and compared with the traditional manual cleaning, mechanical cleaning and chemical cleaning, the method has the advantages that: the cleaning cost is low, the cleaning quality is good, the cleaning speed is high, no environmental pollution is generated, no corrosion is caused to equipment, the high-pressure water jet cleaning technology in China is developed rapidly, the specific gravity of the water jet industrial cleaning is close to 20% in large and medium-sized cities and enterprises, the water jet industrial cleaning speed is increased by about 10% every year, the method is quite promising, the time of 6-7 years is predicted, the high-pressure water jet cleaning technology will occupy absolute advantages in the industrial cleaning industry in China, and the method is a necessary way for the industrial cleaning in China.

Example 2

As a preferred embodiment of the present invention; distilling and heating the raw material by using a reboiler at the bottom end of the gasoline prefractionator, wherein the temperature of the bottom of the gasoline prefractionator is 120-130 ℃, and the temperature of the top of the gasoline prefractionator is 102 ℃;

the distillation tower is mainly divided into a plate tower and a film tower, the plate tower is common, the structure of the plate tower can be divided into three parts of a plate, a reboiler and a condenser, a reboiler inlet is preferably arranged in parallel with a downcomer plate of the tray at the lowest layer, if the plate tower cannot be arranged in parallel due to the arrangement of the tower, the pipe arrangement and the like, a baffle must be considered for installation, the reboiler inlet needs to pay attention to tower material flow so as not to prevent liquid in a liquid receiving tray at the bottom from flowing out, if superheated steam enters the tower, the superheated steam inlet pipe is not suitable to be arranged beside a downcomer pipe for preventing the liquid in the downcomer pipe from being heated and partially vaporized, the superheated steam inlet pipe enters the tower from the reboiler at the bottom and is in countercurrent two-phase contact with the downcomer liquid, the volatile (low boiling point) component in the descending liquid is continuously transferred into the steam, the less volatile (high boiling point) component in the steam is continuously transferred into the descending liquid, the closer the steam is to the tower top, the higher the concentration of the volatile component is, and the closer the descending liquid is to the tower bottom, the more rich the less volatile component is, so as to achieve the purpose of component separation. The vapor ascending from the tower top enters a condenser, one part of the condensed liquid is returned to the tower top as reflux liquid, and the rest part is sent out as distillate. And feeding a part of liquid flowing out of the tower bottom into a reboiler to heat and return the liquid to the tower, and taking the other part of liquid as kettle residual liquid.

Example 3

As a preferred embodiment of the present invention: the cooler cools the gas phase at the top of the gasoline pre-distillation tower to 35 ℃, and naphtha conveyed back to the gasoline pre-distillation tower is used for controlling the temperature at the top of the gasoline pre-distillation tower;

the cooler contains calcium, magnesium ions and bicarbonate because of cooling water mostly, when the cooling water flows through the metal surface, there is the formation of carbonate, in addition, the oxygen of dissolving in the cooling water still can cause the metal to corrode, form the rust, because the production of rust scale, the heat transfer effect descends, have to spray the cooling water outside the casing when serious, can block up the pipe when the scale deposit is serious, make the heat transfer effect lose effect, the data of research show that the loss influence of scale deposit to the heat transfer is huge, can cause the increase of energy cost along with the increase of deposit, the energy saving, the life of extension equipment, save production time and expense simultaneously.

Example 4

As a preferred embodiment of the present invention: the gasoline fractionating tower and the gasoline prefractionator are connected with a conveying pipeline through a vacuum pump;

during the secondary fractionation, the fractionating speed can be increased, and the petroleum is first heated to 400-500 deg.c to become vapor and then fed into the fractionating tower where the higher the temperature is. The petroleum vapors are gradually liquefied, cooled and condensed into liquid fractions on the way up. The gaseous fraction having small molecules and a low boiling point gradually rises along the column and condenses in the upper layer of the column, for example, Fuel Gas (Fuel Gas), Liquefied Petroleum Gas (LPG), light oil (Naphtha), Kerosene (Kerosene), etc., while the liquid fraction having large molecules and a high boiling point condenses in the bottom of the column, for example, Diesel oil (Diesel), lubricating oil, wax, etc. The viscous residue left at the bottom of the column is bitumen and Heavy Oil (Heavy Oil) which can be used as feedstock for coking and bitumen production or as boiler fuel, and the various fractions are collected at each level and transported away from the fractionator via a conduit.

Example 5

As a preferred embodiment of the present invention: the tower bottom pump needs to exchange heat through the heat exchanger twice when conveying oil products;

the temperature of the bottom oil of the tower is changed through the two heat exchangers, so that the oil can be better and more quickly fractionated when the oil enters the gasoline separation tower.

Example 6

As a preferred embodiment of the present invention: the S of the qualified gasoline is less than 10PPM, the S of the unqualified gasoline is more than 10PPM, the carbon dioxide protective layer consists of a hollow iron protective plate and carbon dioxide gas, and the carbon dioxide protective layer is positioned at the outer side of the raw material area;

be convenient for examine the oil to prevent that unqualified oil from sneaking into, the carbon dioxide protective layer can effectively protect the raw materials district, reduces the fire incident, thereby further improves the security performance, reduces the safety risk.

Example 7

As a preferred embodiment of the present invention: comprises the following steps:

the method comprises the following steps: the gasoline feed pump transfers the gasoline in the raw material tank area to a gasoline prefractionator through the heat exchanger for three times of heat exchange;

step two: fractionating gasoline by a reboiler in the gasoline prefractionator to form a top gas phase and bottom oil;

step three: the tower top gas phase exchanges heat through the tower top gas phase through an air cooling heat exchanger, a cooler cools the tower top gas phase to 35 ℃ and then enters a reflux tank, part of naphtha in the tower top reflux tank is pumped back through a reflux pump to control the tower top temperature, and part of naphtha is sent to a naphtha tank area; the non-condensable gas in the reflux tank is controlled by a pressure control valve and then flows to a low-pressure gas buffer tank;

step four: the tower bottom oil is conveyed to a gasoline fractionating tower through a tower bottom pump;

step five: the gasoline fractionating tower is used for carrying out secondary fractionation on the gasoline to form a new tower top gas phase and tower bottom oil in the gasoline fractionating tower;

step six: the gas phase at the top of the tower exchanges heat with the raw material through a tower top oil-gas heat exchanger, and the gas phase at the top of the tower enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, naphtha in the reflux tank reflows through the top of the tower, one part of the naphtha is pumped back to control the temperature at the top of the tower, and the other part of the naphtha is sent to a gasoline;

step seven: and pumping the bottom oil of the gasoline fractionating tower to a heat exchanger through a tower bottom pump for heat exchange, then transferring the bottom oil to a gasoline storage tank after the heat exchange of the heat exchanger, and transferring the qualified national six gasoline to a hydrogenation raw material buffer tank D-105 in a hydrogenation process.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (8)

1. A finished oil fractionation system is characterized in that: the method comprises the following steps:

a raw material area: used for storing raw materials;

carbon dioxide protective layer: used for preventing external fire source;

a gasoline feed pump: used for conveying the raw materials;

a heat exchanger: carrying out heat exchange heating on the product;

a gasoline prefractionator: heating and distilling the raw materials, and controlling the temperature of the top and the bottom of the tower to make the gas phase at the top of the tower pass through an air-cooled heat exchanger, a cooler and a reflux tank;

a reflux pump: conveying a part of naphtha to a gasoline prefractionator, and conveying a part of naphtha to a naphtha tank area;

low-pressure gas buffer tank: for receiving naphtha when the reflux drum is not aerated;

a gasoline fractionating tower: the device is used for receiving the tower bottom of the gasoline prefractionator and distilling the tower bottom oil to form a new tower top gas phase and the tower bottom gasoline, wherein the tower top gas phase exchanges heat with the raw material through a top oil-gas heat exchanger and enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, part of naphtha in the reflux tank is pumped back through a tower top reflux pump to control the tower top temperature, and the other part of naphtha is sent to a gasoline tank area;

a tower bottom pump: and the bottom oil is conveyed to a heat exchanger, qualified gasoline is conveyed to a gasoline storage tank, and unqualified gasoline is conveyed to a hydrogenation process.

2. A finished oil fractionation system according to claim 1, wherein: the raw materials in the raw material area need to be subjected to heat exchange through a heat exchanger for three times before entering a gasoline prefractionator, and the heat exchange is carried out to 60-70 ℃.

3. A finished oil fractionation system according to claim 1, wherein: the gasoline prefractionator utilizes a reboiler at the bottom end of the gasoline prefractionator to distill and heat raw materials, the temperature of the bottom of the gasoline prefractionator is 120-130 ℃, and the temperature of the top of the gasoline prefractionator is 102 ℃.

4. A finished oil fractionation system according to claim 1, wherein: the cooler cools the gas phase at the top of the gasoline pre-distillation tower to 35 ℃, and naphtha conveyed back to the gasoline pre-distillation tower is used for controlling the temperature at the top of the gasoline pre-distillation tower.

5. A finished oil fractionation system according to claim 1, wherein: the gasoline fractionating tower and the gasoline prefractionator are connected with a conveying pipeline through a vacuum pump.

6. A finished oil fractionation system according to claim 1, wherein: the tower bottom pump needs to exchange heat through the heat exchanger twice when conveying oil products.

7. A finished oil fractionation system according to claim 1, wherein: the S of the qualified gasoline is less than 10PPM, the S of the unqualified gasoline is more than 10PPM, the carbon dioxide protective layer consists of a hollow iron protective plate and carbon dioxide gas, and the carbon dioxide protective layer is positioned on the outer side of the raw material area.

8. A finished oil fractionation system according to claim 1, wherein: comprises the following steps:

the method comprises the following steps: the gasoline feed pump transfers the gasoline in the raw material tank area to a gasoline prefractionator through the heat exchanger for three times of heat exchange;

step two: fractionating gasoline by a reboiler in the gasoline prefractionator to form a top gas phase and bottom oil;

step three: the tower top gas phase exchanges heat through the tower top gas phase through an air cooling heat exchanger, a cooler cools the tower top gas phase to 35 ℃ and then enters a reflux tank, part of naphtha in the tower top reflux tank is pumped back through a reflux pump to control the tower top temperature, and part of naphtha is sent to a naphtha tank area; the non-condensable gas in the reflux tank is controlled by a pressure control valve and then flows to a low-pressure gas buffer tank;

step four: the tower bottom oil is conveyed to a gasoline fractionating tower through a tower bottom pump;

step five: the gasoline fractionating tower is used for carrying out secondary fractionation on the gasoline to form a new tower top gas phase and tower bottom oil in the gasoline fractionating tower;

step six: the gas phase at the top of the tower exchanges heat with the raw material through a tower top oil-gas heat exchanger, and the gas phase at the top of the tower enters a gasoline fractionating tower top reflux tank after being cooled by a top aftercooler, naphtha in the reflux tank reflows through the top of the tower, one part of the naphtha is pumped back to control the temperature at the top of the tower, and the other part of the naphtha is sent to a gasoline;

step seven: and pumping the bottom oil of the gasoline fractionating tower to a heat exchanger through a tower bottom pump for heat exchange, then transferring the bottom oil to a gasoline storage tank after the heat exchange of the heat exchanger, and transferring the qualified national six gasoline to a hydrogenation raw material buffer tank D-105 in a hydrogenation process.

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