Flare gas and liquid drop separation device

Abstract

The utility model discloses a flare gas and liquid drop separation device applied to the field of chemical engineering. The flare gas and liquid drop separation device comprises a liquid separation tank and a water-sealed tank, the centrifugal tank is arranged in the center of the liquid separation tank body, the air inlet pipe is tangentially connected with the centrifugal tank, and a sieve plate is arranged at a lower opening of the centrifugal tank and divides the tank body into a diffusion cavity and a cooling cavity. The lower opening of the centrifugal tank is communicated with the diffusion cavity, the upper portion of the cooling cavity is communicated with a connecting pipe, and the pipe end of the connecting pipe is inserted into cooling water of the water-sealed tank. A torch gas pipe penetrates through the center of the centrifugal tank. The sieve plate is in a downward oblique cone shape and is provided with a through hole, and a gap is formed between the sieve plate and the tank body. A cone plate can be arranged in the cooling cavity to strengthen cooling and turbulent flow. The water surface of the water-sealed tank is provided with a buffer net, and the oil surface is provided with a bubble breaking net. According to the utility model, various gas-liquid separation technologies are fused together, the volume of the separation tank is small, the liquid drop separation efficiency is high, and fire rain is avoided.

Description

TECHNICAL FIELD

[0001] The utility model is applied to chemical industry field relates to the safe discharge of flare gas, and specifically relates to a flare gas droplet separation device. BACKGROUND

[0002] In the ethylene production process, the hydrocarbon release stream is mainly gas with entrained droplets, which are mainly from the droplets condensed by temperature cooling or the droplets released with the gas. Especially for flare gas, the droplets condensed due to temperature reduction will affect the safe operation of the flare head. Therefore, the droplets in the flare gas need to be separated before the flare gas enters the flare head for combustion, and the diameter of the droplets should not exceed 200-300 μm to avoid the generation of fire rain.

[0003] Gas-liquid separation device is commonly used in chemical industry to realize material recovery and purification. Droplets or mist are separated from gaseous fluid by gas-liquid separator, or pure gas. The main methods of gas-liquid separation include gravity separation, centrifugal force separation, collision separation, screen separation, filtration separation, baffle separation, and packing separation. There are many patents and applications related to gas-liquid separation devices. For example, CN103170205A is a kind of gas-liquid separation tank for cold hydrogenation process, which is a vertical tank body. Gas and liquid phase outlets are arranged at the upper and lower parts of the tank body respectively. The liquid phase outlet has a liquid level regulating valve. The gas-liquid (containing solid) two-phase medium enters the middle part of the tank body horizontally and tangentially after being discharged from the venturi scrubber, and is separated by centrifugal force and gravity settling. CN110270140A is an automatic exhaust gas-liquid separator, which has the same principle and uses centrifugal force and gravity separation. CN114504882B is a kind of multi-effect cascade gas-liquid separation method and device. The liquid droplets in the gas flow are removed to below 10 μm by using a cyclone tube. The gas carrying liquid droplets below 10 μm is guided to pass through a coalescence fiber bed and a separation fiber bed in sequence. The fine liquid droplets in the gas are coalesced by the multi-layer coalescence fiber bed, and completely separated in the separation fiber bed, so that the liquid droplets in the gas can be completely removed in an integrated separation tank by the three-effect synergistic intensification of inertial separation, cyclone separation and coalescence separation. CN116139628A is a kind of high-efficiency gas-liquid separator, which designs two-stage separation. The first-stage separation structure in the lower part uses gravity and collision separation, and the second-stage separation structure uses filter core filtration separation. CN206372606U is a spiral cyclone type gas-liquid separator device, which has similar separation principle as above. The first centrifugal separation and the second filtration separation are used. CN206996071U is a gas-liquid separation tank, which uses twice centrifugal separation and upper filtration separation. CN118649476B is a kind of gas-liquid separator and gas-liquid separation method, which uses centrifugal force separation, collision separation and filtration separation. CN202410467U is a kind of gas-liquid separation device, which uses centrifugal force and gravity separation in the lower part, and filtration separation in the upper part. CN204073744U is a kind of gas-liquid separator, which uses four times separation. The lower part uses collision and centrifugal separation twice, and the upper part uses gravity and filtration separation twice. CN219984171U is a kind of gas-liquid separation tank, which uses gravity settling gas-liquid separation by setting a spiral or arc-shaped liquid inlet slide. A baffle is arranged on the liquid inlet slide to further separate gas and liquid by baffle separation principle. CN209155424U is a gas-liquid separation tank, which integrates gravity settling, cyclone separation and screen separation. The cyclone separation chamber is located in the middle part of the tank body and has a conical structure tapering from top to bottom. The gas inlet is tangentially arranged in the upper part of the cyclone separation chamber. The preliminarily separated gas is filtered and separated by the upper screen demister, and then discharged from the gas outlet. A circular cyclone plate with adjustable inclination angle is arranged in the upper part of the cyclone separation chamber to improve the separation effect.

[0004] There are also many patents for gas-liquid separation specially applied to flare gas, such as CN205867886U, a horizontal flare gas liquid separator, and CN205965380U, a vertical flare gas liquid separator, both of which use mist eliminator and gravity separation to separate liquid droplets in flare gas. CN208356304U, a horizontal flare gas liquid separator, uses a gas diffuser tube and a deceleration plate to collide and separate, and a deceleration gravity separation, and a deposition plate in the upper second deposition chamber to lengthen the deposition path and separate gas and liquid with a filter screen. CN212855127U, a new type of liquid separator, is equivalent to gravity separation after flow rate reduction and filter screen separation of a defoaming screen. CN204193698U, a flare gas liquid separator, and CN215232720U, a horizontal flare gas liquid separator, have basically the same idea as the above-mentioned patents. The above-mentioned patents do not consider centrifugal gas-liquid separation, CN208229618U, a new type of flare gas high-efficiency cyclone separation device, tangentially enters the gas inlet pipe to form a spiral gas flow, centrifugally separates liquid droplets, and sets a fairing at the lower part of the gas outlet pipe to separate again with a grid plate or wire mesh and louvers. However, the above-mentioned patents do not consider the effect of temperature drop on liquid droplets in gas. CN211677004U, a cyclone gas-liquid separator, uses the side wall of the tank body to cool the hot gas to achieve gas-liquid separation. The tank body has a large contact area with the outside world, and the heat of the tank body can be transferred to the outside world, so that the side wall of the tank body has a lower temperature. The hot gas enters the tank body tangentially from the inlet, directly contacts the inner wall of the tank body to cool and condense into liquid droplets, the liquid droplets move downward under the action of gravity and accumulate at the bottom of the tank body, and the hot gas is gradually discharged from the gas outlet. CN213160048U, a high-efficiency liquid separator, uses a mist eliminator and a bubble breaker to separate gas and liquid twice, and heats the combustible condensed liquid in the heating chamber to avoid the phenomenon of fire rain during combustion. CN208170409U, a heating device for a flare gas liquid separator, separates gas and liquid by exchanging heat between the liquid component and water to generate flare gas, which is basically the same as the above-mentioned patents. The above-mentioned patents consider the effect of temperature drop on liquid droplet separation, and two consider the effect of temperature rise on flare gas to avoid fire rain. Practical new type content

[0005] The technical problem solved by the utility model is to provide a flare gas liquid droplet separation device which integrates centrifugal separation, gravity separation, collision adsorption separation, and temperature drop condensation separation, and heats the separated flare gas to eliminate micro-liquid droplets and prevent fire rain.

[0006] The utility model adopts the technical scheme: the utility model torch gas liquid drop separation device includes the liquid separation tank, water seal tank and torch gas pipe. The liquid separation tank includes the jar body, air inlet pipe, centrifugal jar, cooling cavity and diffusion cavity. The centrifugal jar is arranged in the jar body center, and the air inlet pipe is connected with the tangential connection of centrifugal jar jar wall, and the mixed gas containing liquid drop can enter tangentially, realizes the centrifugal spiral motion. The lower opening of centrifugal jar sets up sieve plate, and this sieve plate separates the diffusion cavity and cooling cavity between centrifugal jar and jar body. The lower opening of centrifugal jar is communicated diffusion cavity, and the upper portion of cooling cavity is communicated connecting pipe, and the connecting pipe is communicated water seal tank. In the center of centrifugal jar, set up torch gas pipe that penetrates. The sieve plate is lower inclined conical, and sets up gap between the jar body, and facilitates liquid downflow, and the sieve plate is processed with through -hole, and sets up passageway for gas flow.

[0007] Further, to increase the ventilation area of the sieve plate through-hole, facilitate liquid downflow, the taper angle of the sieve plate is preferably less than 60°.

[0008] Further, the diffusion cavity bottom is communicated with the liquid collecting tank through the pipeline, the valve and the liquid discharge pipe are installed at the bottom of the liquid collecting tank, and the liquid discharge can be realized.

[0009] Further, to strengthen cooling and turbulence, a cone plate is arranged in the cooling cavity, and the cone plate is arranged on the inner wall of the jar body and the outer wall of the centrifugal jar. The inclination direction of the cone plate on the inner wall is the same as the inclination direction of the sieve plate, and the inclination direction of the cone plate on the outer wall is opposite to the inclination direction of the sieve plate, facilitating the upward flow of gas. The cone plate and the inner wall of the jar body and the outer wall of the centrifugal jar leave a gap, facilitating the downward flow of liquid.

[0010] Further, to strengthen turbulence and increase the contact between liquid drops and liquid on the cone plate, through-holes are processed on the cone plate.

[0011] Further, the water seal tank is a horizontal tank, which is divided into a liquid chamber and a buffer chamber by a baffle, the buffer chamber is communicated with the torch gas pipe, the liquid chamber is communicated with a water inlet pipe and a water outlet pipe, a pipe end of the connecting pipe is inserted into cooling water, a perforated plate is installed at the pipe end, a buffer net is arranged on the water surface of the cooling water, an oil layer floats on the water surface, a bubble breaking net is arranged on the oil surface of the oil layer, and an opening of a siphon pipe is arranged on the oil surface. The water seal tank can cool the mixed gas and adsorb the liquid in the gas, further realizing gas-liquid separation.

[0012] Further, to strengthen the cooling effect of the centrifugal jar, the top of the jar body can be arranged above the lower opening of the centrifugal jar, and the centrifugal jar extends out of the top of the jar body.

[0013] The utility model has the advantages that the utility model integrates various gas-liquid separation technologies, the separation jar has small volume, and the liquid drop separation efficiency is high. The torch gas is liquid drop-free after heating, and the fire rain is completely eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 For the structure of example 1 schematic diagram;

[0015] Figure 2 For the structure of example 2 liquid tank schematic diagram;

[0016] Figure 3 For the structure of example 3 liquid tank schematic diagram;

[0017] Wherein: 1-tank, 2-gas inlet pipe, 3-centrifugal tank, 4-cooling cavity, 5-sieve plate, 6-diffusion cavity, 7-liquid collection tank, 8-buffer cavity, 9-water inlet pipe, 10-baffle, 11-hole plate, 12-cooling water, 13-water outlet pipe, 14-siphon pipe, 15-buffer net, 16-oil layer, 17-foam breaker net, 18-connection pipe, 19-flare gas pipe, 20-cone plate. DETAILED DESCRIPTION

[0018] For the structure of the utility model, the components not shown in the drawing and the components not detailed in the structure, such as manhole, liquid level meter, thermometer, pressure gauge, liquid level alarm, liquid surface control drain pipe, supporting member, hole plate, buffer net, foam breaker net, etc., all belong to the prior art. The following mixed gas is a gas with liquid droplets, and the flare gas is a gas separated from the liquid droplets. EMBODIMENT

[0019] The flare gas liquid droplet separation device of the embodiment includes a liquid separation tank, a water seal tank, and a flare gas pipe. As shown in the accompanying Figure 1 The liquid separation tank and the water seal tank are connected by the connection pipe 18, and the flare gas pipe 19 passes through the center of the liquid separation tank.

[0020] The liquid separation tank comprises a tank body 1, an air inlet pipe 2, a centrifugal tank 3, a cooling cavity 4, a sieve plate 5, a diffusion cavity 6 and the like. The centrifugal tank 3 is arranged at the center of the tank body 1 of the liquid separation tank, the air inlet pipe 2 is tangentially connected with the tank wall of the centrifugal tank, the mixed gas containing liquid drops can enter the centrifugal tank tangentially along the tank wall, spirally move in the centrifugal tank, and centrifugal separation of the liquid drops is realized. The top of the centrifugal tank is blocked, a flare gas pipe 19 penetrates through the center, the lower opening of the bottom is connected with the diffusion cavity 6, the cross-sectional area of the diffusion cavity 6 is larger than that of the centrifugal tank, the moving speed of the mixed gas in the diffusion cavity is slowed down, and gravity separation of the liquid drops is realized. The lower opening of the centrifugal tank is connected with a conical sieve plate 5, the sieve plate is inclined downward, and the liquid flows downward conveniently. The sieve plate 5 is processed with through holes, when the liquid on the tank wall of the centrifugal tank flows downward along the sieve plate 5, the mixed gas passes through the through holes of the sieve plate, the liquid drops in the gas collide with the liquid on the sieve plate, and collision and adsorption separation are realized. In order to increase the air passing area of the through holes of the sieve plate and facilitate the liquid to flow downward, the taper angle of the sieve plate is preferably less than 60°. The gap between the sieve plate and the tank body is arranged, and the liquid flowing downward on the tank wall of the cooling cavity passes through the diffusion cavity conveniently. The cavity between the tank body 1 and the centrifugal tank 3 is divided into the diffusion cavity and the cooling cavity 4 by the sieve plate, the mixed gas enters the cooling cavity from the through holes of the sieve plate, is cooled in the cooling cavity, and the substances with high condensation points can be atomized and condensed into small liquid drops. The upper part of the tank body is connected with a connecting pipe 18, the mixed gas containing condensed liquid drops is sent into the water seal tank. The liquid drops separated by the separation tank gradually gather to flow downward, pass through the pipeline connected with the bottom of the diffusion cavity 6, and enter the liquid collecting tank 7. The valve and the liquid discharge pipe are installed at the bottom of the liquid collecting tank 7, and the liquid discharge can be realized.

[0021] The water seal tank is a horizontal tank, which is divided into a liquid cavity and a gas cavity by a baffle 10, the gas cavity is a buffer cavity 8, which can prevent the gas pressure of the flare gas from being unstable and buffer the gas pressure. The flowing cooling water 12 is placed in the liquid cavity, and the inlet pipe 9 and the outlet pipe 13 are arranged, and the water amount of the inlet and outlet is kept balanced. The connecting pipe 18 is inserted into the cooling water at the pipe end, and the orifice plate 11 is installed at the pipe end, which can prevent the cooling water from violently fluctuating and is beneficial to disperse the gas. The buffer net 15 is arranged on the water surface of the cooling water to buffer the fluctuation of the water surface. On the water surface of the cooling water, the oil layer 16 is gathered and floats on the water surface, the opening of the siphon pipe 14 is arranged on the oil surface of the oil layer 16, the siphon pipe 14 automatically flows out the excess oil. The bubble breaking net 17 is arranged on the oil surface, which can break the bubbles when the bubbles pass through the oil layer, facilitate the gas to pass through, enter the buffer cavity 8, and then enter the flare gas pipe 19 connected with the buffer cavity.

[0022] The working principle of this embodiment is as follows: A high-temperature mixed gas enters the centrifuge tank tangentially, impacting the tank wall. Bubbles in the mixture break, and under centrifugal force, large droplets are thrown onto the inner wall of the tank, gradually accumulating and flowing downwards along the inner wall. They then fall through the sieve plate to the bottom of the diffusion chamber and enter the collection tank. The mixed gas inside the centrifuge tank is cooled bidirectionally by the central flare pipe and the tank wall before entering the diffusion chamber. Due to the increased space, the flow velocity of the mixed gas slows down and turns upwards, generating turbulence. Some droplets in the mixed gas collide and agglomerate into larger droplets, achieving gravity separation. The mixed gas in the diffusion chamber flows upwards into the cooling chamber through the through-holes in the sieve plate. Some unseparated droplets adhere to the liquid flowing downwards along the sieve plate, achieving collision-adhesion separation. The gas entering the cooling chamber dissipates heat outwards through the tank body. High-freezing-point substances become atomized droplets due to the temperature drop and are sent to the water seal tank along with the gas through the connecting pipe. Simultaneously, the mixed gas flowing in the cooling chamber generates turbulence due to the change in the channel cross-sectional area, causing droplets to collide and separate into larger droplets. The mixed gas entering the water-sealed tank is further cooled by the cooling water. Gases with the second highest freezing point condense into droplets. These droplets aggregate into larger droplets in the cooling water and float to the oil layer, or rise with air bubbles. As they pass through the oil layer, the droplets are adsorbed and remain there, achieving separation. After droplet separation, the flare gas, cooled by the cooling water, is sent to the flare head for combustion through the flare gas pipe. When the flare gas passes through the centrifuge tank, it is heated. Even if there are small droplets in the flare gas, they will be heated into gas, ensuring that the flare gas entering the flare head is droplet-free, completely eliminating fire rain. Example

[0023] This embodiment is a modification of tank 1 in Embodiment 1, as shown in the attached figure. Figure 2 As shown, the top of the tank is positioned above the lower opening of the centrifuge tank, with the centrifuge tank extending beyond the top of the tank body. In this case, the primary function of the cooling chamber 4 is not cooling, but rather to collect the mixed gas and guide it into the connecting pipe. This embodiment enhances the cooling of the mixed gas entering the centrifuge tank. Compared to embodiment 1, it reduces the tank volume, but also decreases the heat dissipation area and the flow path length of the mixed gas in the cooling chamber, increasing the gas-liquid separation burden on the water seal tank. Example

[0024] This embodiment is an improvement on tank 1 in Embodiment 1, as shown in the attached figure. Figure 3 As shown, a conical plate 20 is added inside the cooling chamber. The conical plate on the inner wall of the tank is inclined in the same direction as the sieve plate, while the conical plate on the outer wall of the centrifuge tank is inclined in the opposite direction to the sieve plate, facilitating upward gas flow. The conical plate has two functions: first, it increases the contact area with the gas mixture, enhancing the cooling of the gas mixture; second, it enhances the turbulence of the gas mixture, increasing the probability of liquid collision during gas flow, thereby enhancing gas-liquid separation and reducing the gas-liquid separation pressure of the water seal tank.

[0025] In order to realize the downflow of the liquid on the cone plate, a gap is reserved between the cone plate 20 and the inner wall of the tank body and the outer wall of the centrifugal tank.

[0026] In order to strengthen the turbulent flow and increase the contact between the liquid drops and the liquid on the cone plate, a through hole is processed on the cone plate 20.

[0027] The utility model fuses the centrifugal separation, gravity separation, collision adsorption separation and cooling condensation separation of gas and liquid together, is smaller than the volume of traditional horizontal separation tank or vertical separation tank, and the liquid drop separation efficiency is high. After the flare gas is heated, liquid drop discharge is realized, and the fire rain is completely eliminated. The heating of the flare gas does not use external heat, and energy is saved.

Claims

1. A flare gas droplet separation device comprising a knock-out drum, a water seal drum and a flare gas pipe, characterized in that: The liquid separation tank comprises a tank body, an air inlet pipe, a centrifugal tank, a cooling cavity and a diffusion cavity; the centrifugal tank is arranged at the center of the tank body, the air inlet pipe is tangentially connected with the tank wall of the centrifugal tank, and a sieve plate (5) is arranged at the lower opening of the centrifugal tank, which separates the centrifugal tank and the tank body into the diffusion cavity and the cooling cavity; The lower opening is communicated with the diffusion cavity, the upper part of the cooling cavity is communicated with a connecting pipe, and the connecting pipe is communicated with a water seal tank; a torch gas pipe is arranged at the center of the centrifugal tank; the sieve plate (5) is in the shape of a lower inclined cone, and a gap is arranged between the sieve plate (5) and the tank body; and a through hole is formed in the sieve plate (5).

2. The flare gas droplet separator of claim 1, wherein: The taper angle of the sieve plate (5) is less than 60°.

3. The flare gas droplet separator of claim 1, wherein: The bottom of the diffusion cavity is communicated with a liquid collecting tank through a pipeline.

4. The flare gas droplet separator of claim 1, wherein: A conical plate (20) is arranged in the cooling cavity, and the conical plate (20) is arranged on the inner wall of the tank body and the outer wall of the centrifugal tank; the conical plate (20) on the inner wall is inclined in the same direction as the sieve plate, and the conical plate (20) on the outer wall is inclined in the opposite direction of the sieve plate; and a gap is reserved between the conical plate (20) and the inner wall of the tank body and the outer wall of the centrifugal tank.

5. The flare gas droplet separator of claim 4, wherein: A through hole is formed in the conical plate (20).

6. The flare gas droplet separator of claim 1, wherein: The water seal tank is a horizontal tank, which is divided into a liquid cavity and a buffer cavity by a baffle plate, and the buffer cavity is communicated with the torch gas pipe; the liquid cavity is communicated with a water inlet pipe and a water outlet pipe, and the pipe end of the connecting pipe is inserted into the cooling water, and a hole plate is arranged at the pipe end; a buffer net is arranged on the water surface of the cooling water, and an oil layer is floated on the water surface, a bubble breaking net is arranged on the oil surface of the oil layer, and the oil surface is provided with an opening of a siphon pipe.

7. The flare gas droplet separator of claim 1, wherein: The tank top of the tank body is arranged at the upper part of the lower opening of the centrifugal tank, and the centrifugal tank extends out of the tank top.

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