CN213388519U - Atmospheric tower top oil gas washing dechlorination equipment - Google Patents

Abstract

The utility model discloses a normal pressure tower top oil gas washing dechlorination device, which comprises a horizontal tank body, a washing mixing drum, a gas phase outlet, a water distributing drum, a baffle plate and a dechlorination oil outlet; the washing mixing drum comprises an outer drum body with an open lower end, pore plates which are arranged on the inner wall of the outer drum body and are vertical to the axis of the outer drum body, and washing water pipes which are arranged between two adjacent layers of pore plates and are parallel to the pore plates, wherein the washing water inlets of the washing water pipes are arranged outside the drum wall on the side surface of the outer drum body, the washing water pipes are uniformly provided with spray holes along the circumferential direction of the pipe wall, the pore plates are uniformly provided with dispersion holes, the washing mixing drum is fixedly connected and communicated with the horizontal tank body by the lower end of the outer drum body, and an oil gas inlet is. The utility model can greatly reduce the content of chlorine and chloride in the oil gas, and effectively improve the chloride corrosion resistance and salt deposition resistance of the device; the corrosion resistance of subsequent equipment and pipelines can be improved under the condition of lower material grade.

Description

Atmospheric tower top oil gas washing dechlorination equipment

Technical Field

The utility model belongs to the petrochemical field relates to the washing desorption of corrosivity chloride in the oil gas, and specifically speaking relates to a dechlorination equipment is washed to atmospheric pressure top of tower oil gas.

Background

With the deterioration of crude oil, the content of corrosive impurities such as sulfur, nitrogen, chlorine, etc. in crude oil is significantly increased, and many corrosion problems caused during the processing have become important factors affecting the long-term safe production of the apparatus. HCl generated by hydrolysis or thermal decomposition in the process of processing raw chlorine-containing oil dissolves in condensed water at a low temperature to form 'hydrochloric acid' with strong corrosivity or NH₃In the presence of NH₄Cl。NH₄On one hand, Cl is separated out in a form of solid ammonium chloride salt in a condensation cooling system, and the system is blocked after accumulation; on the other hand, due to NH₄Cl is hygroscopic and can absorb moisture from gaseous fluids, resulting in NH₄Under-scale corrosion by Cl salts. The ammonium chloride salt deposition and hydrochloric acid corrosion caused by chloride ions cause failure accidents such as ammonium chloride salt blockage, perforation leakage and the like of equipment, so that the quantity reduction production or shutdown treatment of the device is caused, and the method becomes a prominent problem influencing the long-period safe and stable operation of refining enterprises. In addition, the atmospheric and vacuum distillation device is often positioned at the front end of the refinery process, and unplanned shutdown accidents can cause shutdown of the whole process, thereby causing huge economic loss and seriously affecting the economic benefits of enterprises.

At present, the common normal pressure tower top chloride corrosion protection measures at home and abroad mainly include the measures of injecting neutralizing agent (amine), injecting corrosion inhibitor, injecting water, improving material grade and the like. The water injection on the one hand absorbs chlorine in the gas phase stream into the water to avoid the formation of ammonium chloride salt and prevent dew point corrosion, and on the other hand dissolves the formed ammonium chloride salt into the water to avoid blocking pipelines and equipment. Therefore, the concentration of liquid-phase chloride ions in the system is reduced, and the gas-phase ammonium chloride is prevented from salt deposition, which becomes the key for controlling the corrosion of the system.

Aiming at the treatment of oil gas at the top of the atmospheric tower, the general process flow commonly adopted in the prior art is as follows: after the oil gas with the temperature of 110-150 ℃ is led out of the top of the normal pressure tower, injecting agent (including organic amine, corrosion inhibitor or neutralizing agent) and water injection are carried out, the temperature of the oil gas is reduced to 105-120 ℃ after the agent is injected with water, the heat of the oil gas is extracted by a heat exchanger, and the oil gas enters a reflux tank after the temperature of the oil gas is reduced to 85-100 ℃. Because dew point corrosion is present and severe, multiple lines or spare equipment are often provided for servicing. Through the separation effect of the reflux tank, the oil phase (part) refluxes to the atmospheric tower or (part) is cooled and then is discharged out of the device, the water phase is recycled or discharged out of the device, and the gas phase is cooled and then enters the subsequent treatment. Although a certain process anticorrosion measure is adopted, the chloride corrosion problem of the normal-pressure tower top cooling system is still more common and serious, the corrosion of the system cannot be completely eliminated by the anticorrosion measure, and a large amount of medicament cost is invested every year; in addition, dew point drift easily occurs when crude oil is frequently switched and the operation is unstable, so that pipelines and heat exchangers are seriously corroded, the maintenance cost is high, the normal pressure device is positioned at the front end of the whole oil refining device, once the normal pressure device is shut down, the shutdown of the whole refinery is possibly caused, and the loss is very large.

At present, water is injected into an oil-gas pipeline or equipment directly by using a water injection nozzle or even without the nozzle, and the injected water cannot be uniformly dispersed and contacted with oil gas because the diameter of the water injection pipe is smaller than the size of the oil-gas process pipeline, so that the water injection effect cannot be guaranteed; for the equipment pipeline system in service, because of purchasing, transporting, storing and the like, the actual processed crude oil of an oil refining enterprise is often greatly different from the designed processed crude oil; meanwhile, crude oil is deteriorated, processed oil products are switched frequently, the process operation is difficult to stabilize, the water injection amount is insufficient, and the front and back drift of the dew point position occurs, so that the capacity of the existing water injection and agent injection facilities is insufficient, and the originally designed equipment pipeline and process anti-corrosion measures cannot be well adapted to the dew point corrosion and NH (hydrogen sulfide) of the system₄The under-deposit corrosion, erosion and the like of Cl salt bring larger corrosion risks to the existing equipment and pipelines.

At present, another method for reducing the chlorine content in the field of petrochemical industry is to arrange dechlorination equipment. Chinese patent CN209093016U (a dechlorinating apparatus for stable top noncondensable gas of reforming apparatus) discloses a dechlorinating apparatus for stable top noncondensable gas of reforming apparatus, wherein the top gas phase passes through the dechlorinating apparatus, and chloride ions in the top gas are removed under the action of dechlorinating agent; chinese patent CN204918487U (an alkylate dechlorination apparatus) discloses an alkylate dechlorination apparatus, which is provided with two-stage dechlorination tanks to reduce the chlorine content in alkylate under the action of dechlorinating agent. However, the dechlorination tank is often large in pressure drop, which increases the energy consumption of the device on the one hand, and is not suitable for a system with lower operation pressure such as an atmospheric tower top on the other hand.

Chinese patent CN205379839U (vortex type dechlorinating device) discloses a vortex type dechlorinating device for quickly dissolving chloride ions and performing solid-liquid separation, which can quickly remove chloride ions in silt and perform solid-liquid separation by vortex type washing, spiral stirring and secondary clear water washing. The device is mainly used for removing chloride ions in a solid phase, is different from the technology for removing chloride ions in a medium with most gas phases, and has rotating parts, so that the energy consumption of the device is increased, and the device is easy to break down.

In summary, the corrosion of the atmospheric tower top is increasingly caused by the deterioration of crude oil and the fluctuation of process operation, and the atmospheric and vacuum distillation unit is often the front-end process flow of the oil refining enterprise, and the shutdown may cause the shutdown of the whole plant. In addition, the oil refining enterprises have more and more long requirements on the maintenance period, and the requirements on a stable and corrosion-controllable normal-pressure tower top operating system are more urgent, so that equipment suitable for effectively reducing chlorine corrosion in oil gas in low-pressure systems such as normal-pressure tower tops is urgently needed to be developed, and a stable and controllable corrosion environment is established for subsequent operation.

SUMMERY OF THE UTILITY MODEL

In order to solve the big, uncontrollable problem of corruption of current ordinary pressure top of the tower chloride corrosion risk, the utility model provides an ordinary pressure top of the tower oil gas washing dechlorination equipment.

The utility model provides a normal pressure tower top oil gas washing dechlorination equipment, which comprises a horizontal tank body, a washing mixing drum, a gas phase outlet, a water distributing drum, a baffle plate and a dechlorination oil outlet, wherein the washing mixing drum, the gas phase outlet, the water distributing drum, the baffle plate and the dechlorination oil outlet are sequentially arranged from left to right along the axis of the horizontal tank body; the washing mixing cylinder is arranged on the outer side of the top of the left end of the horizontal tank body, the gas phase outlet is arranged on the top of the horizontal tank body, the water distribution bag is arranged on the outer side of the bottom of the horizontal tank body, the bottom of the water distribution bag is provided with a chlorine-containing water outlet, the baffle is arranged at the bottom of the horizontal tank body at the downstream of the water distribution bag, and the dechlorinated oil outlet is arranged at the bottom of the horizontal; the washing mixing drum comprises an outer drum body with an open lower end, pore plates which are arranged on the inner wall of the outer drum body and are vertical to the axis of the outer drum body, and washing water pipes which are arranged between two adjacent layers of pore plates and are parallel to the pore plates, wherein the washing water inlets of the washing water pipes are arranged outside the drum wall on the side surface of the outer drum body, the washing water pipes are uniformly provided with spray holes along the circumferential direction of the pipe wall, the pore plates are uniformly provided with dispersion holes, the washing mixing drum is fixedly connected and communicated with the horizontal tank body by the lower end of the outer drum body, and an oil gas inlet is.

The lower end of the outer cylinder body can extend into the horizontal tank body, and the lower end of the outer cylinder body can be in an expanding shape, a straight cylinder shape or a conical closing shape.

The orifice plate can set up to two-layer or multilayer, and the dispersion hole on the orifice plate can also be strip seam or other shapes for the round hole, and from the convenient angle of processing, the dispersion hole should be the round hole, and round hole diameter 1 ~ 50mm, preferred 5 ~ 30 mm. In order to prevent the short circuit of gas phase between the upper layer orifice plate and the lower layer orifice plate, the dispersion holes of the adjacent two layers of orifice plates are staggered, namely the dispersion holes of the lower layer orifice plate correspond to the central area of the part of the upper layer orifice plate without the hole. The orifice plate is used for dispersing oil gas, so that the oil gas uniformly flows downwards without generating large bias flow, thereby fully washing the oil gas and ensuring the washing effect. After the oil gas enters the washing mixing drum from the oil gas inlet, the oil gas flows downwards dispersedly and uniformly under the action of the pore plates, the open pores on the two adjacent layers of the pore plates are arranged in a staggered manner, the stroke of the oil gas in the washing mixing drum is increased, and chloride ions in the oil gas can be more fully dissolved into water.

The water washing pipe can be a straight pipe or an annular pipe, one, two or more than two layers of pore plates can be arranged between the upper layer and the lower layer of the adjacent pore plates, the jet holes on the pipe wall of the water washing pipe can be round holes, can also be strip seams or other shapes, and the jet holes are preferably round holes from the angle of convenient processing. When the washing pipe is a straight pipe, one end in the outer cylinder body is a blind end; when the water washing pipes are arranged into two or more ring pipes, the diameters of the rings in which the ring pipes are arranged can be the same or different. The washing water is sprayed out from the spray holes and contacts with oil gas flowing from top to bottom, the washing water which is dispersed and atomized into small particles is fully mixed with the oil gas which is dispersed and uniformly flows from the pore plates, chloride ions in the oil gas are dissolved into the washing water, the corrosivity of the oil gas is reduced, and the oil gas is purified. When a plurality of water washing pipes are adopted, the water washing water sprayed by the water washing pipes collides with each other and is atomized, so that the mass transfer is promoted. The water washing water is injected in such a way that at least 10-30% of liquid water is contained in the washing mixing cylinder.

As an improved scheme, a partition board is arranged on the inner wall of the horizontal tank body at the downstream of the washing and mixing cylinder and close to the washing and mixing cylinder, the partition board is a circular plate, a gas phase channel is arranged at the upper part of the partition board, and a liquid phase channel is arranged at the lower part of the partition board; the gas phase channel at the upper part of the clapboard can be a square hole or a round hole, and the gas phase from the washing mixing cylinder enters the space of the horizontal tank body at the downstream of the clapboard; the liquid phase channel at the lower part of the partition plate can be in a shape of a slot, a rectangle, a circle or an arch, so that the liquid phase from the washing mixing cylinder enters the space of the horizontal tank body at the downstream of the partition plate, and the area of the liquid phase channel can be calculated according to the flow velocity of the liquid phase in the channel of 1-3 m/s.

As a further improvement scheme, in order to better perform gas-liquid separation and remove liquid carried in a gas phase, a gas-liquid separation element is arranged on an outlet of a gas phase channel on the partition plate, the gas-liquid separation element can be a separation element such as a cyclone separator, a wire mesh demister or a gathering separator, and 1-6 groups of gas-liquid separation elements can be arranged according to the treatment capacity.

In order to better perform liquid-liquid separation and enable washing water and dechlorinated oil to be more thoroughly separated, a liquid-liquid separation element is arranged at the bottom of a horizontal tank body close to a water distribution bag at the upstream of the water distribution bag, the liquid-liquid separation element can be a silk screen coalescer, a silk screen consists of steel wires with the specification of 0.1-2 mm, the thickness of the silk screen is 50-500 mm, the silk screen coalescer has the technical characteristics of large specific surface area numerical value, large flux, small pressure drop and high efficiency, oil phases and water phases are gradually agglomerated into large liquid drops in pores in the coalescer, and continuous oil phases and water phases with obvious phase interface boundary are finally formed; the oil phase is accumulated on the upper part of the liquid phase, and can cross the baffle plate in the horizontal tank body after being accumulated to a certain height, and then flows out of the equipment from the dechlorinated oil outlet on the horizontal tank body.

As a further improvement scheme, in order to better remove the entrainment-shaped liquid in the gas phase, a liquid remover is arranged in front of the gas phase outlet, and the liquid remover is formed by filling wire nets in a round or square metal groove body with two open ends.

The utility model discloses a washing dechlorination equipment working process does:

chlorine-containing oil gas enters the washing mixing cylinder from the oil gas inlet and flows from top to bottom along the pore plate; the water washing water enters from a water washing water inlet on the side surface of a washing mixing cylinder, is sprayed out from a spray hole on the pipe wall of a water washing water pipe and contacts with chlorine-containing oil gas flowing from top to bottom, chloride ions in the chlorine-containing oil gas are fully dissolved into the water washing water, the chlorine-containing oil and the water washing water after full mixing enter an upstream space of a partition plate in a horizontal tank body for primary gas-liquid separation, under the action of gravity, a liquid phase accumulated at the lower part of the space flows out through a liquid phase channel arranged at the lower part of the partition plate, a gas phase and a liquid phase accumulated at the upper part of the space undergo gas-liquid separation from a gas phase channel at the upper part of the partition plate through a gas-liquid separation element to obtain a liquid phase and a gas phase, the liquid phase flowing out from the liquid phase channel at the lower part of the partition plate and the liquid phase separated by the gas-liquid separation element converge into, the oil phase overflows through a baffle plate and then leaves the washing dechlorination equipment from a dechlorination oil outlet, and the separated gas phase leaves the washing dechlorination equipment from a gas phase outlet.

The utility model discloses following beneficial effect has:

1) the oil gas containing chlorine and salt is washed, chlorine and chloride in the oil gas are dissolved in water, the content of the chlorine and the chloride in the oil gas is greatly reduced, the corrosivity of the oil gas is weakened, a stable and corrosion-controllable environment is established for a subsequent system, and the use requirements can be met by selecting materials with lower grades for subsequent equipment and pipelines. Under the trend that the maintenance period is longer and longer, the stable and controllable corrosion environment is beneficial to the long-period operation of the device, and the device has good economic benefit.

2) After the safety and reliability of the system are increased, related bypass, compound lines and standby equipment can be eliminated. The bypass, the compound line and the standby equipment are not used under normal conditions, but corrosive media can be stored for a long time, and inspection personnel pay less attention to the corrosive media, so that problems are easy to occur. The washing and dechlorinating equipment can eliminate related bypass, compound line and standby equipment on one hand, reduce the overall construction cost of the device, and eliminate the damage risk of the bypass, the compound line and the standby equipment on the other hand, so as to improve the safety of the system.

3) The washing water is separated immediately, the load of subsequent equipment and pipelines is not increased, and the risk and the scope of corrosion of the subsequent equipment and the pipelines are reduced.

4) The dispersion and washing of oil gas and the separation of oil phase and water phase are completed in the same equipment, the investment and the occupied area of the device are reduced, all elements are static facilities, the faults are few, the pressure drop of the equipment is small, the energy consumption is low, and the device is suitable for systems with lower pressure such as an atmospheric tower top and the like.

Drawings

FIG. 1 is a schematic diagram of the structure of a washing dechlorination apparatus of the present invention;

FIG. 2 is a schematic diagram of the structure of the orifice plate of the present invention;

FIG. 3 is a schematic structural view of the washing water pipe of the present invention as a straight pipe;

FIG. 4 is a schematic structural view of the water washing pipe of the present invention as an annular pipe;

fig. 5 is a schematic structural diagram of the separator of the present invention.

In the figure: 1-a horizontal tank body, 2-a washing mixing barrel, 3-an outer barrel body, 4-a pore plate, 5-an oil gas inlet, 6-a washing water inlet, 7-a washing water pipe, 8-a partition plate, 9-a cyclone separator, 10-a liquid-liquid separation element, 11-a gas phase outlet, 12-a knockout, 13-a liquid level meter, 14-a dechlorinated oil outlet, 15-a baffle plate, 16-a water distribution drum, 17-a chlorine-containing water outlet, 18-a dispersion hole, 19-a spray hole, 20-a square hole type gas phase channel and 21-a slot type liquid phase channel.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a washing and dechlorinating apparatus of the present invention, the present invention provides an atmospheric tower top oil gas washing and dechlorinating apparatus, which comprises a horizontal tank 1, and a washing and mixing drum 2, a partition plate 8, a cyclone 9, a liquid-liquid separation element 10, a gas phase outlet 11, a knockout 12, a water distribution drum 16, a chlorine-containing water outlet 17, a baffle 15, a dechlorinating oil outlet 14 and a liquid level meter 13, which are sequentially arranged from left to right along the axis of the horizontal tank; the washing mixing drum 2 is arranged on the outer side of the top of the left end of the horizontal tank body 1, the gas phase outlet 11 is arranged on the top of the horizontal tank body 1, the knockout 12 is arranged below the gas phase outlet 11, the water distribution bag 16 is arranged on the outer side of the bottom of the horizontal tank body 1, the bottom of the water distribution bag 16 is provided with a chlorine-containing water outlet 17, the baffle plate 15 is arranged at the bottom of the horizontal tank body 1 at the downstream of the water distribution bag, and the dechlorinated oil outlet 14 is arranged at the bottom; the liquid-liquid separation element 10 is a wire mesh coalescer, and the wire mesh is composed of wire wires with the wire diameter of 0.1-2 mm.

The washing mixing drum comprises an outer drum body 3 with an open lower end, a pore plate 4 arranged on the inner wall of the outer drum body and perpendicular to the axis of the outer drum body, and a washing water pipe 7 arranged between the upper pore plate and the lower pore plate and parallel to the pore plate, wherein a washing water inlet 6 of the washing water pipe is arranged outside the side wall of the outer drum body 3, the lower end of the outer drum body 3 extends into the horizontal tank body 1, and the lower end of the outer drum body is in a conical closing-in shape.

Fig. 2 is the structural schematic diagram of the orifice plate of the present invention, and the orifice plate is uniformly distributed with the dispersion holes 18.

Fig. 3 and 4 are schematic structural views of the washing water pipe, which is a straight pipe and a circular pipe, respectively, and the wall of the washing water pipe is provided with spray holes 19.

As shown in fig. 5, the partition plate is provided with a square-hole gas phase channel 20 at the upper part and a slotted liquid phase channel 21 at the lower part, and the cyclone separator 9 (see fig. 1) can be arranged on the square-hole gas phase channel 20.

As shown in figure 1, the working process of the washing and dechlorinating equipment of the utility model is as follows:

chlorine-containing oil gas enters the washing mixing cylinder 2 from the oil gas inlet 5 and flows from top to bottom along the pore plate 4; washing water enters a washing water pipe 7 from a washing water inlet 6 on the side surface of a washing mixing cylinder, is sprayed out from a spray hole on the pipe wall of the washing water pipe 7 and is contacted with chlorine-containing oil gas flowing from top to bottom, chloride ions in the chlorine-containing oil gas are fully dissolved into the washing water, the chlorine-containing oil and the washing water which are fully mixed enter an upstream space of a partition plate 8 in a horizontal tank body 1 for preliminary gas-liquid separation, under the action of gravity, a liquid phase accumulated at the lower part of the space flows out through a liquid phase channel arranged at the lower part of the partition plate 8, a gas phase and a liquid phase accumulated at the upper part of the space are subjected to gas-liquid separation from a gas phase channel arranged at the upper part of the partition plate 8 through a cyclone separator 9 to obtain a liquid phase and a gas phase, the liquid phase flowing out from the liquid phase channel at the lower part of the partition plate 8 and the liquid phase separated by the cyclone separator, the water phase leaves the washing dechlorination equipment through a chlorine-containing water outlet 17, the oil phase overflows through a baffle 15 and then leaves the washing dechlorination equipment from a dechlorination oil outlet 14, and the separated gas phase leaves the washing dechlorination equipment from a gas phase outlet 11.

Claims (9)

1. The utility model provides an atmospheric pressure top of tower oil gas washing dechlorination equipment which characterized in that: comprises a horizontal tank body, a washing mixing cylinder, a gas phase outlet, a water distributing bag, a baffle plate and a dechlorination oil outlet which are sequentially arranged from left to right along the axis of the horizontal tank body; the washing mixing cylinder is arranged on the outer side of the top of the left end of the horizontal tank body, the gas phase outlet is arranged on the top of the horizontal tank body, the water distribution bag is arranged on the outer side of the bottom of the horizontal tank body, the bottom of the water distribution bag is provided with a chlorine-containing water outlet, the baffle is arranged at the bottom of the horizontal tank body at the downstream of the water distribution bag, and the dechlorinated oil outlet is arranged at the bottom of the horizontal; the washing mixing drum comprises an outer drum body with an open lower end, pore plates which are arranged on the inner wall of the outer drum body and are vertical to the axis of the outer drum body, and washing water pipes which are arranged between two adjacent layers of pore plates and are parallel to the pore plates, wherein the washing water inlets of the washing water pipes are arranged outside the drum wall on the side surface of the outer drum body, the washing water pipes are uniformly provided with spray holes along the circumferential direction of the pipe wall, the pore plates are uniformly provided with dispersion holes, the washing mixing drum is fixedly connected and communicated with the horizontal tank body by the lower end of the outer drum body, and an oil gas inlet is.

2. The apparatus of claim 1, wherein: the lower end of the outer cylinder body extends into the horizontal tank body, and the lower end of the outer cylinder body is in an opening expanding shape, a straight cylinder shape or a conical closing shape.

3. The apparatus of claim 1, wherein: the dispersion holes on the pore plate are round holes or strip seams.

4. The apparatus of claim 1, wherein: the water washing water pipe is a straight pipe or a ring pipe, and two or more straight pipes or ring pipes are arranged between two layers of pore plates which are adjacent up and down.

5. The apparatus of claim 4, wherein: the diameters of the circular rings in which the circular pipes are arranged are the same or different.

6. The apparatus of claim 1, wherein: the inner wall of the horizontal tank body at the downstream of the washing mixing cylinder, which is close to the washing mixing cylinder, is provided with a partition board which is a circular plate, the upper part of the partition board is provided with a gas phase channel, and the lower part of the partition board is provided with a liquid phase channel.

7. The apparatus of claim 6, wherein: and a gas-liquid separation element is arranged on an outlet of the gas-phase channel on the partition plate.

8. The apparatus of claim 1, wherein: and a liquid-liquid separation element is arranged at the bottom of the horizontal tank body at the upstream of the water dividing bag, close to the water dividing bag.

9. The apparatus of claim 1, wherein: a liquid removing device is arranged in front of the gas phase outlet and is formed by filling a wire mesh in a round or square metal groove body with two open ends.

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