Gas-liquid mass transfer device for deoxygenating boiler water, method for deoxygenating boiler water and application thereof

Abstract

The present invention relates to the field of boiler water utilization, and in particular, to a gas-liquid mass transfer device for boiler water deoxygenation, a method for boiler water deoxygenation, and an application thereof. The gas-liquid mass transfer device for boiler water deoxygenation comprises a cylindrical cyclone chamber with equal diameters at the top and bottom, a flat cyclone chamber arranged above the cyclone chamber, and a liquid seal groove arranged below the cyclone chamber. The gas-liquid mass transfer device for boiler water deoxygenation has the characteristics of high deoxygenation accuracy and small volume, and has high mass transfer characteristics. The mass fraction of dissolved oxygen in the water after deoxygenation does not exceed 5 ppb.

Description

Technical Field

[0001] The invention relates to the field of boiler water utilization, and in particular to a gas-liquid mass transfer device for deoxygenating boiler water, a method for deoxygenating boiler water and applications thereof. Background Art

[0002] Deoxygenation is an important link in the boiler feed water treatment process. Oxygen-corrosive substances such as iron oxide will enter the boiler and deposit or adhere to the boiler tube wall and heating surface, forming insoluble iron scale with poor heat transfer, reducing the heat exchange rate, reducing the boiler output efficiency, and wasting energy. At the same time, the iron scale with poor heat transfer adheres to the furnace tube, which can easily cause the furnace tube to overheat and creep, thereby causing a tube burst accident. Oxygen-corrosive iron scale will cause pitting and pitting on the inner wall of the pipeline. When the pipeline is severely corroded, pipeline perforation, leakage, and even explosion accidents will occur.

[0003] In the traditional process, thermal deoxygenation methods and equipment are used. The boiler feed water is heated to 102-104℃ and the operating pressure is 20kPa. The solubility of oxygen is reduced, and oxygen in the water continuously escapes. Then the oxygen generated on the water surface is separated together with the water vapor. The steam consumption is large, generally consuming 18-20% of the boiler steam output. Another commonly used method is vacuum deoxygenation, which reduces steam consumption, but increases the cost and energy consumption of vacuum equipment. The additional moving equipment makes it difficult to operate smoothly for a long period of time. Energy consumption costs have become the main part of the cost of boiler water deoxygenation. Reducing energy consumption has become an important way to reduce costs, improve economic benefits, and survive and develop enterprises. Chemical deoxygenation, or the use of combined methods such as thermal rough deoxygenation + deep deoxygenation with chemicals, increases the risk of boiler operation and is costly. Pressure thermal deoxygenation process equipment has high energy consumption. The vacuum membrane method is used for deoxygenation, and the long-term stability problem of membrane equipment has not yet been solved.

[0004] Enhanced stripping mass transfer rate refers to using carrier gas to reduce the partial pressure of dissolved gas, thereby transferring dissolved gas from liquid phase stripping to carrier gas, which can achieve higher separation efficiency at lower temperatures and is a low-temperature and low-consumption boiler deoxygenation water process. With the improvement of energy conservation and consumption reduction levels and the proposal of the dual-carbon strategy, low-consumption deoxygenation process routes using nitrogen as the stripping medium have emerged one after another.

[0005] In the power industry, the prior art provides a method and device for deoxygenating nitrogen from cooling water in the valve cooling system of a UHV converter station. The separation of dissolved oxygen can be achieved at a relatively low temperature without heating the water. The relatively low temperature brings an unfavorable factor regarding the thermodynamic diffusion mass transfer, so the contact efficiency of nitrogen and water needs to be improved. The prior art proposes a waste heat boiler deoxygenation system and deoxygenation process, using nitrogen as a stripping carrier gas and a hollow fiber membrane as a gas-liquid mass transfer device. The dissolved oxygen in the boiler feed water is usually 50-70 ppb, and the dissolved oxygen content is relatively high.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] One aspect of the present invention relates to a gas-liquid mass transfer device for deoxygenating boiler water, comprising a cylindrical cyclone chamber with equal diameters at the top and bottom, a flat cyclone chamber arranged above the cyclone chamber, and a liquid seal groove arranged below the cyclone chamber;

[0008] The swirl chamber comprises an upper end surface with a closed top and a lower port with an open bottom; a spiral portion is arranged in the swirl chamber, and the spiral portion comprises a rotating shaft arranged at the central axis position of the swirl chamber and a spiral blade connected to the rotating shaft; the outer edge diameter of the spiral blade is equal to the cross-sectional diameter of the swirl chamber; and a through hole is arranged on the surface of the spiral blade;

[0009] A horizontally arranged liquid receiving tank is also included between the spiral blade and the upper end surface, one end of the liquid receiving tank is connected to the inner wall of the cyclone chamber, and an overflow weir is vertically arranged at the other end;

[0010] The liquid sealing groove is a groove body with an opening at the upper end, used to contain the liquid sealing liquid, and the lower port of the swirl chamber is arranged below the liquid level of the liquid sealing liquid;

[0011] The side wall of the cyclone chamber is also provided with at least one gas inlet, wherein at least one of the gas inlets is provided in the first lead region of the spiral blade;

[0012] The flat swirl chamber is a chamber structure with a closed lower bottom surface and an air outlet on the upper bottom surface, and an air riser is connected between the upper end surface of the swirl chamber and the lower bottom surface of the flat swirl chamber;

[0013] A downcomer is also arranged above the cyclone chamber, the downcomer penetrates the flat cyclone chamber, and one end of the downcomer extends outward through the gas outlet, and the other end of the downcomer is arranged in the cyclone chamber and above the liquid receiving tank;

[0014] The flat-swirl chamber also includes at least one liquid tangential feed pipe horizontal to the lower bottom surface, and the outer tube wall of each liquid tangential feed pipe has at least one connection point with the inner wall of the flat-swirl chamber.

[0015] The gas-liquid mass transfer device for boiler water deoxygenation has the characteristics of high mass transfer, greatly reduces nitrogen consumption and tail gas emissions, and reduces water loss. The economic benefits of steam savings are far greater than the cost of nitrogen consumption. It is of great significance for energy distribution and boiler water heat exchange in petrochemical plants.

[0016] The mass transfer rate of bubbles in the cyclone field is higher. On the one hand, the residence time of liquid micro-clusters at the gas-liquid interface is greatly shortened due to the vortex effect. On the other hand, the bubbles in the centrifugal velocity field are affected by centrifugal force, drag, lift, buoyancy, etc. Based on momentum transfer analysis, the slip velocity between bubbles and liquid is much greater than the bubble floating velocity under the gravity field. The microscopic vortex caused by velocity pulsation and the rapid slip of bubbles in the cyclone field greatly increase the gas-liquid interface renewal rate. The cyclone field can effectively improve the total mass transfer coefficient and improve the gas lift effect. Using a cyclone channel to construct a cyclone field with a certain degree of turbulence can effectively separate trace dissolved oxygen in boiler water.

[0017] In the flat cyclone field, the carrier gas and liquid are injected from the tangential inlet of the side wall of the cyclone chamber to form a gas-liquid cyclonic flow. The gas-liquid two-phase flows from the side wall to the central outlet. The liquid is a continuous phase and exhibits tangential cyclonic motion. Under the action of the liquid cyclone, the gas presents a bubble form and exhibits radial penetrating centripetal motion, forming a two-phase flow state of liquid tangential cyclone and gas radial penetrating flow. Under the conditions of cyclone centrifugal acceleration, the gas and liquid form a turbulent cross-flow state, the mass transfer rate is greatly improved, the soluble components in the liquid can be transferred to the carrier gas in a very short time, the carrier gas consumption is lower, and the equipment is more compact.

[0018] In the spiral flow field, the injected carrier gas moves from bottom to top, part of it forms a gas continuous phase under the spiral blade, and part of it passes through the micropores of the spiral blade to form bubbles above the spiral blade. The bubbles come into contact with the downward flowing liquid, and gas-liquid mass transfer occurs. The liquid on the upper surface of the spiral blade presents a foam flow, and the mass transfer rate is extremely high.

[0019] Preferably, a fillet is provided at the connection position between the gas outlet and the flat-swirl chamber, and the fillet radius is 5 to 30 mm.

[0020] Preferably, the through holes arranged on the surface of the spiral blade have a diameter of 0.1 to 0.9 mm (eg, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 0.9 mm).

[0021] Preferably, the surface porosity of the spiral blade is 0.0001 to 0.1 (for example, 0.0001, 0.0005, 0.001, 0.005, 0.01, 0.05 or 0.1).

[0022] Preferably, the spiral blade has a thickness of 0.2-1 mm (eg, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm or 1 mm). The area around the aperture is thinned.

[0023] Preferably, the spiral blade is formed by rotating a blade with an inclined rectangular cross-section, and the angle β between the rectangular cross-section and the horizontal line is 5 to 20 degrees (for example, 5 degrees, 10 degrees, 15 degrees, 18 degrees or 20 degrees).

[0024] Preferably, the height of the spiral blade is 0.5 to 6 m (0.5 m, 1 m, 2 m, 3 m, 4 m, 5 m or 6 m).

[0025] Preferably, the outer edge diameter of the spiral blade is 50 to 500 mm (50 mm, 80 mm, 110 mm, 140 mm, 170 mm, 200 mm, 230 mm, 260 mm, 290 mm, 320 mm, 350 mm, 380 mm, 410 mm, 440 mm, 470 mm or 500 mm).

[0026] Preferably, the ratio of the inner edge diameter to the outer edge diameter of the spiral blade is 0.01 to 0.2 (eg, 0.01, 0.05, 0.1, 0.15 or 0.2).

[0027] The top side of the spiral blade is a liquid inlet or a gas outlet, and the bottom side of the spiral blade is a liquid outlet or a gas inlet; the spiral blade is a single-lead, the outer edge diameter is equal to the diameter of the outer wall, and the inner edge diameter of the spiral blade is equal to the diameter of the rotating shaft.

[0028] Preferably, the ratio of the pitch (L) of the spiral blade to the outer wall diameter of the spiral blade is 0.1-2 (e.g., 0.1, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8 or 2).

[0029] The spiral blade has a circular hole. The thinner the blade thickness around the circular hole, the easier it is for bubbles to penetrate from the bottom of the blade to the top. Too thick a circular hole wall will inhibit the number of bubbles formed. Such a spiral blade structure optimizes the flow velocity of the liquid on the surface of the spiral blade, which determines the efficiency of gas-liquid mass transfer in the unit space. The appropriate velocity range on the surface of the spiral blade can take into account the mass transfer enhancement effect of liquid turbulence on the bubble interface and maintain a suitable liquid residence time.

[0030] Preferably, a bubble damper is arranged above the riser.

[0031] Preferably, the center of mass of the bubble damper is located below the tangency point between the liquid tangential feed tube and the flat swirl chamber.

[0032] Preferably, the bubble damper comprises an inclined plate and a horizontal baffle facing the tangential feeding direction of the liquid.

[0033] Preferably, the distance between the horizontal baffle and the lower bottom surface of the flat-spinning chamber is 0.5-5 mm (for example, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm); the horizontal projection shape size of the horizontal baffle is (4.5-5.5) × (4.5-5.5) mm.

[0034] The liquid injected from the tangential inlet forms a strong shearing effect in the wake area of ​​the gas damper, so that the gas entering the riser is split into numerous fine bubbles, thereby increasing the gas-liquid contact area.

[0035] Preferably, the number of the liquid tangential feeding tubes is 1 to 16 (eg, 1, 5, 10, 15 or 16).

[0036] Preferably, the diameter of the liquid tangential feed pipe is 8 to 50 mm (e.g., 8 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm).

[0037] Preferably, the ratio of the straight tube length of the liquid tangential feeding tube to the diameter of the liquid tangential feeding tube is ≥3.5 (eg, 3.5, 4.5, 5.5 or 6.5).

[0038] Preferably, the height of the overflow weir is 30-100 mm (for example, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm).

[0039] Preferably, the distance between the plane where the lower port of the downcomer is located and the liquid receiving tank is 5 to 30 mm (eg, 5, 10, 15, 20, 25 or 30).

[0040] Preferably, the lower end surface of the downcomer is lower than the upper end surface of the overflow weir.

[0041] Preferably, the distance (h) between the plane where the upper port of the liquid seal groove is located and the plane where the lower port of the cyclone chamber is located is 50-200 mm (50 mm, 70 mm, 90 mm, 110 mm, 120 mm, 140 mm, 160 mm, 180 mm or 200 mm). This distance is set to prevent a large amount of gas from escaping from the bottom by short circuit.

[0042] Preferably, when a plurality of gas inlets are arranged on the side wall of the swirl chamber, the first gas inlet is arranged in the first lead of the spiral blade; the nth gas inlet is arranged in the (10-50)nth lead of the spiral blade.

[0043] The lead area of ​​the spiral blade close to the lower port of the swirl chamber is the first lead area.

[0044] Preferably, the liquid phase processing capacity of the gas-liquid mass transfer device for deoxygenating boiler water is 0.5 to 5 t / h (for example, 0.5 t / h, 1 t / h, 1.5 t / h, 2 t / h, 2.5 t / h, 3 t / h, 3.5 t / h, 4 t / h, 4.5 t / h or 5 t / h).

[0045] When the liquid flow rate exceeds 5 tons / hour, the gas-liquid mass transfer device for deoxygenating boiler water of the present invention can be combined in parallel to meet the amplification requirements.

[0046] Another aspect of the present invention also relates to a method for deoxygenating boiler water, using the gas-liquid mass transfer device for deoxygenating boiler water, comprising the following steps:

[0047] (a) The boiler water to be treated enters the flat vortex chamber through the liquid tangential feed pipe; the carrier gas enters the vortex chamber from the gas inlet, passes through the spiral blades and the riser pipe, and enters the flat vortex chamber;

[0048] The temperature of the boiler water to be treated is 45-80°C (e.g., 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C);

[0049] (b) In the flat swirl chamber, the boiler water to be treated and the carrier gas rotate and flow, the carrier gas is discharged from the gas outlet, and the boiler water to be treated passes through the downcomer, the liquid receiving tank and the overflow weir in sequence and enters the spiral blade;

[0050] (c) The boiler water to be treated flows from top to bottom in the spiral blades, and the carrier gas moves from bottom to top in the spiral blades, forming a gas-liquid countercurrent contact; a part of the carrier gas forms a gas continuous phase below the spiral blades, and a part of the carrier gas passes through the micropores of the spiral blades to form bubbles above the spiral blades. The liquid on the upper surface of the spiral blades presents a foam flow. After the boiler water to be treated passes through the spiral blades and enters the liquid seal tank, it is discharged from the liquid overflow outlet, and the carrier gas enters the riser.

[0051] The boiler water deoxygenation method has more economical cyclone stripping process parameters, and can achieve effective and reasonable utilization of energy in the boiler water deoxygenation process. The method is based on the existing conditions of nitrogen, steam, etc. in petrochemical plants, and adopts a nitrogen and steam combination to reduce the overall energy consumption cost and improve the overall energy utilization efficiency of the boiler water deoxygenation process.

[0052] Preferably, the centrifugal acceleration of the rotating flow is 5 to 60 times (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 times) the acceleration of gravity.

[0053] Preferably, the Reynolds number of the liquid phase of the rotational flow is 3000-11000 (e.g., 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000 or 11000).

[0054] Preferably, when the temperature of the boiler water to be treated is less than 50° C., the ratio of the volume flow rate of the carrier gas to the volume flow rate of the boiler water to be treated is ≥2 (eg, 2, 3, 4, 5 or 6).

[0055] Preferably, when the temperature of the boiler water to be treated is 50-80° C., the ratio of the volume flow rate of the carrier gas to the volume flow rate of the boiler water to be treated is 0.1-2 (eg, 0.1, 0.2, 0.5, 0.8, 1, 1.4, 1.8 or 2).

[0056] Preferably, the carrier gas includes at least one of nitrogen, helium or argon.

[0057] Another aspect of the present invention also relates to a boiler water deoxygenation system, including the gas-liquid mass transfer device for boiler water deoxygenation.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The gas-liquid mass transfer device for boiler water deoxygenation provided by the present invention has the characteristics of high deoxygenation accuracy and small size, and has high mass transfer characteristics. The nitrogen consumption and tail gas emissions are greatly reduced, and the water loss is reduced at the same time. The economic benefits of the saved steam are far greater than the cost of nitrogen consumption. It is of great significance for the energy distribution and boiler water heat exchange of petrochemical equipment.

[0060] (2) The method for deoxygenating boiler water provided by the present invention uses a low-grade heat source from a petrochemical device to preheat boiler water, and optimizes nitrogen consumption according to the preheating temperature to obtain a stable boiler water deoxygenation effect; the method for deoxygenating boiler water provided by the present invention has the advantages of high separation efficiency and low energy consumption, and the mass fraction of dissolved oxygen in the water after deoxygenation does not exceed 5 ppb. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0062] Figure 1 It is a front view of the gas-liquid mass transfer device for deoxygenating boiler water of the present invention;

[0063] Figure 2It is a schematic diagram of the three-dimensional structure of the gas-liquid mass transfer device for deoxygenating boiler water according to the present invention;

[0064] Figure 3 It is a side view of the plano-rotation chamber of the present invention;

[0065] Figure 4 A top view of the planar rotation chamber of the present invention;

[0066] Figure 5 It is a schematic diagram of the structure of the swirl chamber of the present invention;

[0067] Figure 6 It is a schematic diagram of the boiler water deoxygenation process of the present invention.

[0068] Reference numerals:

[0069] 1-gas outlet, 2-downcomer, 3-swirl chamber, 4-overflow weir, 5-spiral blade, 6-swirl chamber, 7-gas inlet, 8-liquid overflow outlet, 9-liquid seal tank, 10-liquid tangential feed pipe, 11-rising gas pipe, 12-liquid receiving tank, 13-bubble damper, 14-separator, 15-compressor, 16-boiler booster pump, 17-gas-liquid mass transfer device. DETAILED DESCRIPTION

[0070] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0071] Example 1

[0072] The gas-liquid mass transfer device 17 for deoxygenating boiler water provided in this embodiment is as follows: Figure 1 to Figure 5 As shown, it comprises a cylindrical cyclone chamber 6 with equal diameters at the top and the bottom, a flat cyclone chamber 3 arranged above the cyclone chamber 6, and a liquid sealing groove 9 arranged below the cyclone chamber 6;

[0073] The swirl chamber 6 comprises an upper end surface with a closed top and a lower port with an open bottom; a spiral portion is arranged in the swirl chamber 6, and the spiral portion comprises a rotating shaft arranged at the central axis position of the swirl chamber 6 and a spiral blade 5 connected to the rotating shaft; the outer edge diameter of the spiral blade 5 is equal to the cross-sectional diameter of the swirl chamber 6; and a through hole is arranged on the surface of the spiral blade 5;

[0074] A horizontally arranged liquid receiving tank 12 is further provided between the spiral blade 5 and the upper end surface, one end of the liquid receiving tank 12 is connected to the inner wall of the cyclone chamber 6, and an overflow weir 4 is vertically provided at the other end;

[0075] The liquid sealing groove 9 is a groove body with an opening at the upper end, used to contain the liquid sealing liquid, and the lower port of the swirl chamber 6 is arranged below the liquid level of the liquid sealing liquid;

[0076] The side wall of the cyclone chamber 6 is also provided with at least one gas inlet, wherein at least one of the gas inlets is provided in the first lead region of the spiral blade 5;

[0077] The flat swirl chamber 3 is a cavity structure with a closed lower bottom surface and an air outlet on the upper bottom surface. An air riser 11 is connected between the upper end surface of the swirl chamber 6 and the lower bottom surface of the flat swirl chamber 3.

[0078] A downcomer 2 is further arranged above the cyclone chamber 6, the downcomer 2 penetrates the flat cyclone chamber 3, and one end of the downcomer 2 extends outward through the gas outlet, and the other end of the downcomer 2 is arranged in the cyclone chamber 6 and above the liquid receiving tank 12;

[0079] The flat swirl chamber 3 further includes at least one liquid tangential feed pipe 10 horizontal to the lower bottom surface, and the outer tube wall of each liquid tangential feed pipe 10 has at least one connection point with the inner wall of the flat swirl chamber 3;

[0080] A bubble damper 13 is arranged above the riser 11; the center of mass of the bubble damper 13 is located below the tangent point between the liquid tangential feed pipe 10 and the flat swirl chamber 3;

[0081] The distance between the horizontal baffle of the bubble damper 13 and the lower end surface of the flat swirl chamber 3 is 1mm; the gas outlet 1 and the flat swirl chamber 3 are connected at a fillet with a radius of 20mm; a through hole is set on the surface of the spiral blade 5, the opening rate is 0.01, the aperture of the through hole is 0.5mm, the blades around the through hole are thinned, and the thickness of the blades around the through hole is 0.8mm; the rectangular cross section of the spiral blade 5 is 15 degrees with the horizontal angle β, the ratio of the pitch L of the spiral blade 5 to the outer wall diameter is 0.3, and the total diameter of the spiral blade 5 is 0.5mm. The height is 4 meters; the number of liquid tangential feed pipes 10 is 1, the diameter is 8 to 50 mm, and the straight pipe length of the liquid tangential feed pipe 10 is equal to 4 times the diameter of the liquid tangential feed pipe 10; the height of the overflow weir 4 is 50 mm, and the distance between the plane where the lower port of the downcomer 2 is located and the liquid receiving tank 12 is 10 mm; the distance between the plane where the upper port of the liquid seal tank 9 is located and the lower end face of the cyclone chamber 6 is 100 mm, and the diameter of the rotating shaft of the spiral blade 5 is equal to 0.02 times the diameter of the outer wall, and the outer wall diameter is 400 mm.

[0082] Example 2

[0083] In the boiler water deoxygenation system of the present invention, the gas-liquid mass transfer device 17 is arranged in the separator 14 (such as Figure 6 As shown), the separator 14 has a gas phase outlet at the top, and the external tank has a liquid phase outlet at the bottom. The gas phase outlet of the separator is connected to the circulating gas compressor 15 and the outside. The circulating gas compressor 15 is connected to the nth gas inlet 7. The liquid phase outlet of the separator is connected to the boiler booster pump 16.

[0084] Example 3

[0085] The boiler water deoxygenation method provided in this embodiment, using the gas-liquid mass transfer device 17 for boiler water deoxygenation provided in Example 1, comprises the following steps:

[0086] (1) Use low-grade heat source from petrochemical plants to preheat water;

[0087] (2) Water enters the flat swirl chamber 3 through the liquid tangential feed pipe 10, and the carrier gas enters the flat swirl chamber 3 from the gas riser 11 and the bubble damper 13. The gas and liquid flow in a rotational manner inside the flat swirl chamber 3; the gas and liquid flow in a spiral from the side wall of the flat swirl chamber 3 to the center of the flat swirl chamber 3;

[0088] (3) There are a gas outlet 1 and a downcomer 2 near the center of the flat-swirl chamber 3. The gas with a lower density is discharged from the gas outlet 1, and the water with a higher density flows downward from the downcomer 2;

[0089] (4) Water from the downcomer 2 enters the liquid receiving tank 12, passes through the overflow weir 4 and enters the spiral blade 5;

[0090] (5) The liquid flows from top to bottom on the spiral blade 5, and the gas moves from bottom to top on the spiral blade 5, forming a gas-liquid countercurrent contact; part of the gas forms a gas continuous phase below the spiral blade 5, and part of the gas passes through the micropores of the spiral blade 5 to form bubbles above the spiral blade 5. The liquid on the upper surface of the spiral blade 5 presents a foam flow, the liquid flows into the liquid seal section, and the gas enters the riser 11;

[0091] (6) The liquid flows into the liquid seal section and is discharged through the liquid overflow outlet 8, completing the deoxygenation and separation of the boiler water.

[0092] The liquid flow rate is 8 tons / hour, and two sets of cyclone-enhanced gas-liquid mass transfer devices 17 are connected in parallel to meet the amplification requirements; the liquid in the cyclone chamber 3 rotates, the centrifugal acceleration is 40 times the gravity acceleration, and the liquid phase Reynolds number is 8900; the liquid phase processing capacity of each gas-liquid mass transfer device 17 is 4 tons / hour; the carrier gas is nitrogen, the preheated water temperature is 76°C, and the ratio of the volume flow rate of nitrogen gas to the volume flow rate of water is 0.3; the mass fraction of dissolved oxygen in the deoxygenated water is 3ppb.

[0093] Example 4

[0094] In a catalytic cracking unit, the boiler water feed water is preheated to 45°C through a low-grade heat source, and the boiler water flow rate is 200t / h. This embodiment uses the device of Example 1 and the method of Example 3 to deoxygenate the boiler water. The difference from Example 3 is the flow rate and preheating temperature;

[0095] The liquid flow rate is 200 tons / hour, and 50 sets of cyclone enhanced gas-liquid mass transfer devices 17 are connected in parallel to meet the amplification requirements. The liquid phase processing capacity of each cyclone enhanced gas-liquid mass transfer device 17 is 4 tons / hour; the preheated water temperature is 45°C, and the ratio of the volume flow rate of nitrogen gas to the volume flow rate of water is 2.2:1; the mass fraction of dissolved oxygen in the deoxygenated water is 4ppb.

[0096] Comparative Example 1

[0097] In a catalytic cracking unit, the boiler feed water is heated by steam to 102-104°C, the operating pressure is 20kPa, the steam consumption is 40t / h, and the mass fraction of dissolved oxygen in the water after deoxygenation is 10ppb.

[0098] By comparing and analyzing the comparative examples and the embodiments, it can be seen that the boiler water deoxygenation method and device provided by the present invention have good deoxygenation effect. The mass fraction of dissolved oxygen in the water after deoxygenation does not exceed 5ppb. The deoxygenation effect is better than that of the traditional thermal deoxygenation method, which is of great significance for the energy distribution of petrochemical equipment and boiler water heat exchange.

[0099] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A gas-liquid mass transfer device for deoxygenating boiler water, characterized in that: It comprises a cylindrical cyclone chamber with equal diameters at the top and the bottom, a flat cyclone chamber arranged above the cyclone chamber, and a liquid sealing groove arranged below the cyclone chamber; The swirl chamber comprises an upper end surface with a closed top and a lower port with an open bottom; a spiral portion is arranged in the swirl chamber, and the spiral portion comprises a rotating shaft arranged at the central axis position of the swirl chamber and a spiral blade connected to the rotating shaft; the outer edge diameter of the spiral blade is equal to the cross-sectional diameter of the swirl chamber; and a through hole is arranged on the surface of the spiral blade; A horizontally arranged liquid receiving tank is also included between the spiral blade and the upper end surface, one end of the liquid receiving tank is connected to the inner wall of the cyclone chamber, and an overflow weir is vertically arranged at the other end; The liquid sealing groove is a groove body with an opening at the upper end, which is used to contain the liquid sealing liquid, and the lower port of the swirl chamber is arranged below the liquid level of the liquid sealing liquid; The side wall of the cyclone chamber is also provided with at least one gas inlet, wherein at least one of the gas inlets is provided in the first lead region of the spiral blade; The flat swirl chamber is a chamber structure with a closed lower bottom surface and an air outlet on the upper bottom surface, and an air riser is connected between the upper end surface of the swirl chamber and the lower bottom surface of the flat swirl chamber; A downcomer is also arranged above the cyclone chamber, the downcomer penetrates the flat cyclone chamber, and one end of the downcomer extends outward through the gas outlet, and the other end of the downcomer is arranged in the cyclone chamber and above the liquid receiving tank; The flat-swirl chamber also includes at least one liquid tangential feed pipe horizontal to the lower bottom surface, and the outer tube wall of each liquid tangential feed pipe has at least one connection point with the inner wall of the flat-swirl chamber.

2. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The through holes arranged on the surface of the spiral blade have a diameter of 0.1-0.9 mm.

3. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The surface opening rate of the spiral blade is 0.0001-0.

1.

4. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The spiral blade has a thickness of 0.2-1 mm.

5. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The height of the spiral blade is 0.5-6m.

6. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The outer edge diameter of the spiral blade is 50-500 mm.

7. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The ratio of the inner edge diameter to the outer edge diameter of the spiral blade is 0.01-0.

2.

8. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The ratio of the pitch of the spiral blade to the outer wall diameter of the spiral blade is 0.1-2.

9. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: A bubble damper is arranged above the riser.

10. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 9, characterized in that: The center of mass of the bubble damper is located below the tangency point between the liquid tangential feed tube and the flat swirl chamber.

11. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The number of the liquid tangential feeding pipes is 1 to 16.

12. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The height of the overflow weir is 30-100 mm.

13. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The distance between the plane where the lower port of the downcomer is located and the liquid receiving tank is 5-30 mm.

14. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The distance between the plane where the upper port of the liquid seal groove is located and the plane where the lower port of the swirl chamber is located is 50-200 mm.

15. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: When a plurality of gas inlets are arranged on the side wall of the swirl chamber, the first gas inlet is arranged in the first lead of the spiral blade; the nth gas inlet is arranged in the (10-50)nth lead of the spiral blade.

16. The gas-liquid mass transfer device for boiler water deoxygenation according to claim 1, characterized in that: The liquid phase processing capacity of the gas-liquid mass transfer device for deoxygenating boiler water is 0.5~5t / h.

17. A method for deoxygenating boiler water, using the gas-liquid mass transfer device for deoxygenating boiler water according to any one of claims 1 to 16, characterized in that: The following steps are involved: (a) The boiler water to be treated enters the flat swirl chamber through the liquid tangential feed pipe; the carrier gas enters the swirl chamber from the gas inlet, passes through the spiral blades and the riser pipe and enters the flat swirl chamber; The temperature of the boiler water to be treated is 45-80°C; (b) In the flat swirl chamber, the boiler water to be treated and the carrier gas rotate and flow, the carrier gas is discharged from the gas outlet, and the boiler water to be treated passes through the downcomer, the liquid receiving tank and the overflow weir in sequence and enters the spiral blade; (c) the boiler water to be treated flows from top to bottom in the spiral blades, and the carrier gas moves from bottom to top in the spiral blades, forming gas-liquid countercurrent contact; The boiler water to be treated passes through the spiral blades and enters the liquid seal tank and is discharged from the liquid overflow outlet, and the carrier gas enters the riser.

18. The method for deoxygenating boiler water according to claim 17, characterized in that: The centrifugal acceleration of the rotating flow is 5 to 60 times the acceleration of gravity.

19. The method for deoxygenating boiler water according to claim 17, characterized in that: The Reynolds number of the liquid phase of the rotating flow is 3000-11000.

20. The method for deoxygenating boiler water according to claim 17, characterized in that: When the temperature of the boiler water to be treated is less than 50° C., the ratio of the volume flow rate of the carrier gas to the volume flow rate of the boiler water to be treated is ≥2.

21. The method for deoxygenating boiler water according to claim 17, characterized in that: When the temperature of the boiler water to be treated is 50-80° C., the ratio of the volume flow rate of the carrier gas to the volume flow rate of the boiler water to be treated is 0.1-2.

22. A boiler water deoxygenation system, characterized in that: A gas-liquid mass transfer device for deoxygenating boiler water comprising the device described in any one of claims 1 to 16.

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