CN112797830B - Cooling method and cooling device for high-viscosity heavy oil - Google Patents

Abstract

The invention belongs to the field of petroleum refining and petrochemical industry, and particularly discloses a cooling method and a cooling device for high-viscosity heavy oil products, wherein the cooling method comprises the following steps: the high-temperature heavy oil enters the tube pass of the water tank cooler and is discharged after exchanging heat with water in the shell pass of the water tank cooler, the water in the shell pass of the water tank cooler is heated and vaporized into water vapor, the water vapor is discharged from a vapor outlet on a vapor ascending tube or is collected to an air cooler through the vapor ascending tube for cooling, and the cooled condensate water returns to the shell pass of the water tank cooler through a condensate water descending tube to form self circulation. The invention combines the water tank cooler and the air cooler, effectively recycles the water vapor and solves the problems of large water consumption and easy environmental pollution in the prior art.

Description

Cooling method and cooling device for high-viscosity heavy oil

Technical Field

The invention belongs to the field of petroleum refining and petrochemical industry, and particularly relates to a cooling method and a cooling device for high-viscosity heavy oil products.

Background

In the process of petroleum processing and refining, heavy oil is often generated, and the heavy oil not only contains solid mechanical impurities such as catalyst dust, but also has the characteristics of high specific gravity, high viscosity, poor low-temperature fluidity and the like. In order to meet the requirements of subsequent processing or storage, the temperature of the steel is required to be reduced. A common cooling mode in the field of petrochemical engineering is to utilize heat exchange equipment to transfer heat between high-temperature materials and other cold media, so that cooling is realized, and the high-temperature materials reach the specified temperature. If the heavy material containing catalyst dust flows in the heat exchange tube at a high flow velocity, the power loss is overlarge, the erosion of the catalyst dust and solid mechanical impurities to the tube wall is also serious, and if the flow velocity is low, the heat transfer coefficient is too low, the required heat transfer area is overlarge, and the catalyst dust and the mechanical impurities are easy to deposit and scale to cause the blockage of heat exchange equipment, so that the common heat exchange equipment is not suitable any more, and great difficulty is brought to the structure selection of the heat exchange equipment.

At present, a water tank is generally adopted to solve the above-mentioned problems. The advantage of using the water tank for cooling is that the influence of the cooling water temperature on the coefficient of the heat transfer film at the heat medium side is small, and the heat transfer has large heat transfer temperature difference; however, the water tank has the defects that cooling water in the water tank is communicated with the atmosphere, vapor vaporized after the cooling water is heated is directly discharged into the atmosphere, water resource waste is caused, the environment is polluted, and the development of a brand-new cooling device and a cooling method becomes an important task in the current industrial production.

Disclosure of Invention

The invention aims to solve the problems of high water consumption and environmental pollution in the cooling process of high-viscosity heavy oil products by providing a cooling device and a cooling method of the high-viscosity heavy oil products.

In order to achieve the above object, an aspect of the present invention provides a cooling method for a high-viscosity heavy oil product, the cooling method comprising:

the high-temperature heavy oil enters the tube side of the water tank cooler and is discharged after exchanging heat with water in the shell side of the water tank cooler, the water in the shell side of the water tank cooler is heated and vaporized into water vapor, the water vapor is discharged from a vapor outlet on a vapor ascending tube or is collected to an air cooler through the vapor ascending tube for cooling, and the cooled condensate water returns to the shell side of the water tank cooler through a condensate water descending tube to form self circulation.

Another aspect of the present invention provides a cooling device for a high-viscosity heavy oil product, the cooling device comprising:

the water tank cooler is provided with a shell pass and a tube pass;

the steam ascending pipe is provided with a steam outlet;

the air cooler is arranged above the water tank cooler and is connected with an outlet of a shell pass of the water tank cooler through the steam ascending pipe;

the condensed water downcomer is connected with the air cooler and the inlet of the shell pass of the water tank cooler; the cooling device does not include a power plant.

Compared with the prior art, the invention has the following advantages:

(1) According to the invention, the water tank cooler and the air cooler are combined, so that water resources are recycled, cooling water is added only once without considering leakage, water consumption is greatly reduced, and the problem of high water consumption in the prior art is solved; meanwhile, the air cooler can be stopped, and the water tank cooler can be independently used as a steam generator.

(2) According to the invention, the automatic circulation of water vapor between the water tank cooler and the air cooler is realized by reasonably setting the mounting height difference between the water tank cooler and the air cooler, no power transmission equipment is additionally arranged, the investment and the related operating cost are saved, and the occupied area of the equipment is reduced.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts throughout.

FIG. 1 is a schematic view of a cooling apparatus for high viscosity heavy oil products in an embodiment of the present invention

FIG. 2 is a schematic diagram showing the pressure drop of different parts and different positions of the cooling device for high viscosity heavy oil products in one embodiment of the present invention

Description of reference numerals:

1. a water tank cooler; 2. an air cooler; 3. a steam riser pipe; 4. a condensate downcomer; 5. a water replenishing port; 6. a heavy oil inlet; 7. a heavy oil product outlet; 8. a steam outlet; 9. shell side liquid level;

m, frequency conversion control; t, controlling the temperature; l, liquid level control; H. the height from the liquid level in the condensate water descending pipe to the bottom end of the condensate water descending pipe; h. the height from the liquid level of the water tank cooler to the bottom end of the condensate water downcomer;

P_a gas phase pressure above the liquid level of the water tank cooler; p_b Gas phase pressure above the liquid level in the condensed water descending pipe; p is_c The outlet liquid phase pressure at the bottom end of the condensed water downcomer; delta P₁ Pressure drop of the steam through the steam riser; delta P₂ Pressure drop of the steam through the air cooler; delta P₃ And the pressure drop of the condensed water passing through the condensed water downcomer.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

One aspect of the present invention provides a method for cooling a high-viscosity heavy oil product, the method comprising:

the high-temperature heavy oil enters the tube pass of the water tank cooler and is discharged after exchanging heat with water in the shell pass of the water tank cooler, the water in the shell pass of the water tank cooler is heated and vaporized into water vapor, the water vapor is discharged from a vapor outlet on a vapor ascending tube or is collected to an air cooler through the vapor ascending tube for cooling, and the cooled condensate water returns to the shell pass of the water tank cooler through a condensate water descending tube to form self circulation.

The water tank cooler is combined with the air cooler, so that refrigerant water exchanges heat with high-viscosity heavy oil products and absorbs heat for gasification, the air cooler cools and condenses steam, condensed water is sent back to the shell pass of the water tank cooler and is recycled as a refrigerant, automatic circulation is formed without arranging power conveying equipment, investment is saved, operation cost is reduced, and water vapor is not lost. When steam needs to be generated, the water tank cooler is used as a steam generator, the air cooler is stopped, and the steam is discharged from the steam outlet.

According to the invention, preferably, the temperature of the high-temperature heavy oil product after heat exchange is adjusted by controlling the operating pressure of the air cooler variable frequency fan and/or the shell side of the water tank cooler, and the heat exchange load of the water tank cooler is adjusted by controlling the water temperature of the shell side.

The invention can be operated in a closed mode or in an open mode by means of the basic principle of the water tank and adopting a closed design, so that the water tank cooler can operate under the condition of pressure rise or normal pressure.

In the invention, the steam which exchanges heat with high-temperature heavy oil and is vaporized rises from the steam ascending pipe, and the steam generates pressure drop in the condensation process of the air cooler, so that the pressure in the steam ascending pipe is higher than the pressure in the condensed water descending pipe, and the liquid in the condensed water descending pipe is communicated with the water tank cooler, and the liquid level of the condensed water descending pipe is higher than the liquid level of the water tank cooler.

Another aspect of the present invention provides a cooling device for a high-viscosity heavy oil product, the cooling device comprising:

the water tank cooler is provided with a shell pass and a tube pass;

the steam ascending pipe is provided with a steam outlet;

the air cooler is arranged above the water tank cooler and is connected with an outlet of a shell pass of the water tank cooler through the steam ascending pipe;

the condensed water downcomer is connected with the air cooler and the inlet of the shell pass of the water tank cooler; the cooling device does not include a power plant.

According to the invention, the installation height difference between the water tank cooler and the air cooler is set to meet the driving force requirement of water vapor circulation flow, so that water vapor is condensed by the air cooler and then returns to the water tank cooler, automatic circulation is formed without arranging power conveying equipment, and meanwhile, water vapor is not lost. Preferably, the height from the liquid level in the condensed water descending pipe to the bottom end of the condensed water descending pipe is H, the height from the liquid level of the water tank cooler to the bottom end of the condensed water descending pipe is H, and the installation height difference is greater than (H-H). (H-H) the specific calculation method is as follows:

P_a ＝P_b +△P₁ +△P₂ +△P₃ formula 1

P_a +ρgh＝P_cFormula 2

P_b +ρ’gH＝P_cFormula 3

Wherein:

rho is the density of the coolant water in the water tank cooler;

ρ' — the density of the condensed water in the condensed water downcomer.

Is obtained by formula 1,formula 2 and formula 3:

ρ’gH-ρgh＝△P₁ +△P₂ +△P₃ formula 4

Considering that the refrigerant water and the condensed water are both close to a saturated state, the temperature is basically consistent, the density difference can be ignored, and the calculation can be obtained as follows: H-H = ([ Delta ] P)₁ +△P₂ +△P₃ )/(ρg)。

In order to ensure the self-circulation flow of the water vapor, preferably, the condensed water downcomer is immersed below the water tank cooler shell Cheng Yemian, and further preferably, the condensed water downcomer is immersed not less than 10mm below the water tank cooler shell side liquid level.

The cooling device for the high-viscosity heavy oil disclosed by the invention can be provided with a liquid level meter on the shell pass of the water tank cooler, the top of the water tank cooler is provided with a water replenishing port, and the side part of the water tank cooler is provided with a heavy oil inlet and a heavy oil outlet. Wherein, the selection of the water tank cooler is not limited, and the water tank cooler can be a square tank or a horizontal tank which is conventional in the field; the selection of the air cooler is also conventional in the field, and is often selected to be a constant-frequency fan or a variable-frequency fan.

Examples

The material conditions involved in this example were as follows:

high-viscosity heavy oil: the pre-cooling temperature is 220 ℃, the post-cooling temperature is 198 ℃, the flow rate is 47297kg/h, and the average specific heat is 0.467 kcal/(kg-DEG C).

Refrigerant water: saturated deoxygenated water at 106 ℃.

Water tank cooler shell side operating pressure: 0.03MPagG.

The cooling device for the high-viscosity heavy oil in the embodiment includes:

the horizontal tank type water tank cooler 1 is provided with a shell pass and a tube pass, the shell pass is provided with a liquid level meter, the top of the shell pass is provided with awater replenishing port 5, and the side part of the shell pass is provided with aheavy oil inlet 6 and aheavy oil outlet 7;

asteam riser pipe 3 provided with asteam outlet 8;

theair cooler 2 is arranged above the water tank cooler 1, adopts a variable frequency fan and is connected with an outlet of a shell pass of the water tank cooler 1 through thesteam ascending pipe 3;

the condensed water downcomer 4 is connected with the outlet of theair cooler 2 and the inlet of the shell pass of the water tank cooler 1; the condensed water downcomer 4 is immersed below the liquid level of the shell side of the water tank cooler 1 by 800mm;

the cooling device does not include a power plant.

The method for calculating the installation height difference between the water tank cooler 1 and theair cooler 2 comprises the following steps:

taking the height from the liquid level in the condensate water descending pipe to the bottom end of the condensate water descending pipe as H, and the height from the liquid level of the water tank cooler 1 to the bottom end of the condensate water descending pipe as H;

under 0.03MPaG, the saturation temperature of the deoxygenated water is 106 ℃, the enthalpy of the deoxygenated water is 106.7kcal/kg, and the enthalpy of the saturated steam is 641.5kcal/kg. The high-viscosity heavy oil enters the water tank cooler through theheavy oil inlet 6 and is discharged from theheavy oil outlet 7, and the required cooling load is 0.486Mkcal/h according to calculation. Because the steam self-circulation does not consider the heat dissipation loss, the steam circulation evaporation capacity is as follows: 0.486X 10⁶ /(641.5-106.7)＝908.6kg/h。

Thesteam ascending pipe 3 is selected from the pipe diameter DN200, the equivalent length is 20m, and the condensate water descending pipe 4 is selected from the pipe diameter DN100m, and the equivalent length is 10m. Due to the water vapor on the steamThe flow velocity in theriser 3 is lower, and the flow velocity of water in the condensate water downcomer 4 is lower, so that the pressure drop delta P is generated₁ 、△P₃ Small and negligible. The length of the air cooler is 6m, the width is 1m, the tube pass is 1, the tube rows are 2, the diameter of the tube bundle is 25mm, and the pressure drop delta P of the air cooler is obtained by calculation₂ ＝2.1kPa。

And because the density of the condensed water is 953.6kg/m³ Therefore, it is made

H–h＝(△P₁ +△P₂ +△P₃ )/(ρg)

＝2.1×10³ /(953.6×9.81)

＝0.22m

Namely, the height difference between the outlet position of theair cooler 2 and the liquid level position of the water tank cooler 1 needs to be larger than 0.22m, the factors such as the levelness of field installation are considered, a proper margin is reserved, and the distance between the outlet position of theair cooler 2 and the top of the water tank cooler 1 is not less than 0.6m when the air cooler is installed.

The cooling device for the high-viscosity heavy oil product is used for cooling the high-viscosity heavy oil product, and the specific flow is shown in figure 1. Under the ordinary pressure, high temperature heavy oil gets into 1 tube side of water tank cooler, discharges after carrying out the heat transfer with the water in 1 shell side of water tank cooler, and the water in 1 shell side of water tank cooler receives the thermal gasification to steam, collectsair cooler 2 throughsteam tedge 3 and cools off, and the comdenstion water of formation returns 1 shell side of water tank cooler through comdenstion water downcomer 4, need not set up power conveying equipment and forms automatic cycle promptly. When steam generation is required, the water tank cooler 1 is used as a steam generator, theair cooler 2 is deactivated, and the generated steam is discharged through asteam discharge port 8.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims (4)

1. A cooling method for a high-viscosity heavy oil product is characterized by comprising the following steps:

high-temperature heavy oil products enter a tube pass of a water tank cooler (1) and are discharged after heat exchange with water in a shell pass of the water tank cooler (1), the water in the shell pass of the water tank cooler (1) is heated and vaporized into water vapor, the water vapor is discharged from a vapor discharge port (8) on a vapor ascending tube (3) or is collected to an air cooler (2) through the vapor ascending tube (3) for cooling, and cooled condensed water returns to the shell pass of the water tank cooler (1) through a condensed water descending tube (4) to form self circulation;

the pressure in the steam ascending pipe (3) is greater than the pressure in the condensed water descending pipe (4), and the liquid level height in the condensed water descending pipe (4) is greater than the liquid level height in the shell side of the water tank cooler (1); the condensed water downcomer (4) is immersed below the liquid level of the shell pass of the water tank cooler (1);

the temperature of the high-temperature heavy oil after heat exchange is adjusted by controlling the operating pressure of a variable frequency fan of the air cooler (2) and/or the shell pass of the water tank cooler (1), and the heat exchange load of the water tank cooler (1) is adjusted by controlling the water temperature of the shell pass;

the operating pressure of the water tank cooler (1) is greater than or equal to the normal pressure;

the cooling device used in the cooling method comprises:

the water tank cooler (1) is provided with a shell pass and a tube pass;

the steam ascending pipe (3) is provided with a steam outlet (8);

the air cooler (2) is arranged above the water tank cooler (1) and is connected with an outlet of a shell pass of the water tank cooler (1) through the steam ascending pipe (3);

the condensed water downcomer (4) is connected with the air cooler (2) and the inlet of the shell pass of the water tank cooler (1); the cooling device does not include a power plant;

the shell side of the water tank cooler (1) is provided with a liquid level meter, and the top of the water tank cooler is provided with a water replenishing port (5);

the installation height difference between the water tank cooler (1) and the air cooler (2) is set to meet the requirement of driving force for circulating flow of water vapor;

taking the height from the liquid level in the condensed water descending pipe to the bottom end of the condensed water descending pipe as H, the height from the liquid level of the water tank cooler to the bottom end of the condensed water descending pipe as H, and the installation height difference is greater than H-H;

wherein H-H is represented by the formula H-H = ([ delta ] P)₁ +△P₂ +△P₃ ) V (ρ g) calculated;

△P₁ for the pressure drop of the steam through the steam riser, Δ P₂ Delta P is the pressure drop of the steam through the air cooler₃ Is the pressure drop of the condensed water passing through the condensed water downcomer;

ρ is the density of water in the shell side;

the water in the shell pass is saturated deoxygenated water.

2. A cooling device for a high-viscosity heavy oil product, characterized by comprising:

a water tank cooler (1) provided with a shell pass and a tube pass;

the steam ascending pipe (3) is provided with a steam outlet (8);

the air cooler (2) is arranged above the water tank cooler (1) and is connected with an outlet of a shell pass of the water tank cooler (1) through the steam ascending pipe (3);

the condensed water downcomer (4) is connected with the air cooler (2) and the inlet of the shell pass of the water tank cooler (1); the cooling device does not include a power plant;

the installation height difference between the water tank cooler (1) and the air cooler (2) is set to meet the driving force requirement of water vapor circulation flow;

taking the height from the liquid level in the condensed water descending pipe to the bottom end of the condensed water descending pipe as H, the height from the liquid level of the water tank cooler to the bottom end of the condensed water descending pipe as H, and the installation height difference is greater than H-H;

the condensed water downcomer (4) is immersed below the liquid level of the shell side of the water tank cooler (1);

the shell side of the water tank cooler (1) is provided with a liquid level meter, and the top of the water tank cooler is provided with a water replenishing port (5);

wherein H-H is represented by the formula H-H = ([ Delta ] P)₁ +△P₂ +△P₃ ) V (ρ g) calculated;

△P₁ for the pressure drop of the steam through the steam riser, Δ P₂ Pressure drop, Δ P, for steam passing through the air cooler₃ Is the pressure drop of the condensed water passing through the condensed water downcomer;

ρ is the density of water in the shell side.

3. A cooling device according to claim 2, wherein the condensate downcomer (4) is immersed no less than 10mm below the shell side liquid level of the water box cooler (1).

4. A cooling arrangement according to any one of claims 2-3, wherein the tank cooler side is provided with a heavy oil inlet (6) and a heavy oil outlet (7); the water tank cooler (1) is a square tank or a horizontal tank; and the fan of the air cooler (2) is a fixed-frequency fan or a variable-frequency fan.

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