RU2680069C1 - Disc-shaped scrubber - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to the field of petrochemistry and can be used, in particular, in the processes of obtaining olefinic hydrocarbons used in the production of synthetic rubbers, plastics, high-octane components of gasoline and other organic products. Disc-shaped scrubber, irrigated with water, is proposed for cooling and cleaning contact gas in the olefinic hydrocarbon production processes by dehydrating the corresponding paraffinic hydrocarbons, including vertical cylindrical housing 1, comprising a contact gas injection unit located in the lower bottom of the housing in the form of central pipeline 2 with baffle 4 located above its upper edge 3, dead tray 5, separating scrubber housing 1 to the first stage of contacting contact gas 6 and the water scrubber supplied for irrigation in the lower part of the scrubber and second stage 7 — in its upper part, and representing a horizontal partition with cup 8 located in the central part along the axis of housing 1, having baffle 10 along the contact gas above its upper edge 9, each stage of contact 6, 7 has circulation pipeline 13, 16, equipped with pump 11, 12 for independent circulation of water through these stages of contact 6, 7, moreover, the pipeline 13 of the first stage 6 is connected to pipeline 14, located below upper edge 3 of central pipeline 2 for contact gas injection, and with pipe 15 for circulating water injection to irrigate the first stage of contact 6, and pipe 16 of the second stage 7 is additionally equipped with heat exchanger-cooler 17 of the circulating water and connected to pipe 18 located above the dead plate 5 below upper edge 9 of cup 8, and with the pipe 20 for circulating water injection to irrigate the second stage of contact 7 through distributor 22, which also contains liquid trap 23 installed in the upper bottom of housing 1, connected to pipeline 58 for withdrawing contact gas from the scrubber, in which the first stage of contact 6 contains three ring-shaped, located horizontally and sequentially along the contact gas flow perforated or grid trays — gas-distribution tray 24 and two working trays 25, 26 for contacting contact gas and circulating water — with the ratio of clear opening of the trays, respectively 1:(0.3–0.7):(0.15–0.5), each of working trays 25, 26 is a non-turbo grid tray for water and has a circulating water distribution device containing an annular receiving pocket 27, 28 located in the peripheral part of the tray with an overflow threshold in the form of an annular vertical overflow partition 29, 30, the upper edge 35, 36 of which is located in a horizontal plane, for receiving circulating water and distributing it over the web of the tray, as well as distribution boxes 31, 32 of cylindrical shape located in the central part of the trays, the upper edges of which are in the horizontal plane and are located below or at the level of the upper edges 35, 36 of the annular overflow partitions 29, 30, forming overflow thresholds, moreover, distribution boxes 31, 32 have overflow pipes 37, 38, the lower edges 39, 40 of which are located below the upper edge 3 of pipeline 2 for contact gas injection under the level of the water layer in the bottom part of the scrubber, the circulation pipeline of the first contacting stage 6 is connected to pipe 15 located in receiving pocket 27 of lower working tray 25, and the scrubber has one or more overflow pipes 44, 45 located outside or inside scrubber housing 1, moreover, upper ends 46, 47 of these pipes are located below upper edge 9 of cup 8 of dead tray 5, and the lower ends — in receiving pocket 28 of upper working tray 26 or above it. At the same time, upper end 47 of overflow pipe 45, located inside scrubber housing 1, is equipped with a cap, which creates water seal 56 when the excess water overflows from the second stage of contact 7.EFFECT: technical result is to increase the efficiency of heat and mass transfer in a disc-shaped scrubber, to ensure an increase in the degree of cleaning of contact gas from catalyst dust, a decrease in the temperature of contact gas at the outlet of the scrubber and obtaining pure hot water suitable for use as a coolant in surface heat exchangers, in relation to the requirements of the implementation processes for the production of olefinic hydrocarbons by dehydrogenating the corresponding paraffinic hydrocarbons.13 cl, 1 dwg, 3 tbl, 2 ex

Description

The invention may find application in the refining, petrochemical, chemical and other industries. It may be effective to use the invention, in particular, in the processes for producing olefin hydrocarbons used in the production of synthetic rubbers, plastics, high-octane gasoline components and other important organic products.

A single-stage plate scrubber is known for cooling and purifying contact gas from catalytic dust of butane, isobutane and isopentane dehydrogenation processes in reactors with a fluidized bed of finely dispersed aluminum-chromium catalyst, irrigated with water circulating in the scrubber that is cooled in a heat exchanger-cooler. Recycled industrial water is fed to the heat exchanger to cool the water circulating in the scrubber (NN Lebedev, “Chemistry and technology of basic organic and petrochemical synthesis”, Publishing house “Chemistry”, M, 1988, pp. 468-470).

A disadvantage of the known scrubber is the low cooling efficiency (up to 60-70 ° C) and the cleaning of the contact gas from catalyst dust in a single-stage scrubber with trellised plates.

Close in technical essence to the proposed one is a single-stage heat and mass transfer apparatus for cooling and purifying contact gas from catalyst dust with water condensate during the production of styrene by dehydrogenation of ethylbenzene (patent RU 2345813, IPC B01D 3/32; B01D 53/18, publ. 10.02.2009). The apparatus has a vertical cylindrical body, a central pipeline for introducing contact gas with a chipper located axially symmetrically to the body of the apparatus, two perforated ring-shaped gratings. The apparatus also contains a cylindrical distribution box located in the central part of the gratings with an upper edge for condensate overflow from the upper grate. The distribution box is equipped with a drain pipe, the lower end of which is located below the level of condensate in the bottom part of the apparatus. The apparatus also has nozzles for introducing condensate into the annular receiving box with an annular overflow threshold on the upper grate, nozzles for measuring the level of condensate in the bottom part of the apparatus, a nozzle for removing water condensate from the apparatus for cleaning. The contact gas passes sequentially through the perforated gratings and is directed through the spray trap to the stages of condensation and styrene evolution. Obtained at the stage of condensation, the water condensate of the process is sent to the annular receiving box of the heat and mass transfer apparatus. The stream of water condensate evenly irrigates the upper perforated grate through an annular overflow threshold at the periphery of the grate, passes the grate in the radial direction, crosswise to the contact gas flow, and through the drain threshold formed by the upper edge of the distribution box, the drain pipe enters the level of the water condensate layer in the bottom part apparatus, from where it is sent for purification and use in the process of dehydrogenation of ethylbenzene. The upper perforated grate operates in a non-liquid foam mode (I.P. Mukhlenov, E.Ya. Tarat, “Foam mode and foam apparatus”, Khimiya Publishing House, 1977, p. 278), and the lower lattice remains “dry” and works as a distribution for gas. However, the cooling efficiency (from 180-250 ° C to 70-90 ° C) and the cleaning of the contact gas from the catalyst dust in the specified single-stage heat and mass transfer apparatus does not satisfy the requirements for large-scale processes for the dehydrogenation of paraffin hydrocarbons.

The closest in technical essence and the achieved result is a two-stage plate scrubber with two independent water circuits used in the process of producing n-butylenes by dehydrogenation of n-butane in a fluidized bed of finely dispersed aluminum-chromium catalyst (I.L. Kirpichnikov, V.V. Beresnev, L .M. Popov, “The album of technological schemes of the main industries of the synthetic rubber industry”, “Chemistry”, Leningrad, 1986, p. 8-14). The specified plate scrubber, irrigated with water, for cooling and purifying the resulting dehydrogenation contact gas from catalyst dust, includes a vertical cylindrical body containing a contact gas input unit located in the lower part of the body and connected to the contact gas inlet pipe to the scrubber, a blank plate separating the scrubber body on the first step of contacting with trellised plates in the lower part of the scrubber and the second step also with trellised plates in its upper part. A blank plate is a horizontal partition with a glass located in its central part along the body axis, having a chipper along the contact gas above its upper edge. Each contact stage has its own circulation pipe equipped with a pump for independent water circulation through the specified contact stages, the first stage pipe being connected to a pipe located below the contact gas input unit and to the circulating water input pipe for irrigation of the first contact stage, and the second stage pipe is additionally equipped with a circulating water heat exchanger-cooler and is connected to a pipe located above a blank plate below the upper edge of the glass and with a nozzle for introducing circulating water for irrigation of the second stage of contacting, also containing a splash trap installed in the upper bottom of the housing connected to a nozzle for discharging contact gas from the scrubber. In a known scrubber, the contact gas is cooled from 350-400 ° C to 50 ° C.

To heat the evaporator of raw materials in the specified known method for producing n-butylene by dehydrogenation of n-butane, hot water with a temperature of 82-98 ° C, obtained at the stage of subsequent dehydrogenation of n-butylene to butadiene, is a two-stage production of butadiene from n-butane (I.I. Yukelson, “The Technology of Basic Organic Synthesis”, M, Chemistry Publishing House, 1968, p. 184).

The disadvantages of the known scrubber include:

- low efficiency of cooling and purification of contact gas from catalyst dust, associated mainly with a low level of heat and mass transfer when using ineffective grating plates. So, for example, in the first stage of the scrubber, a sufficient degree of purification of the contact gas is not provided, which leads to a breakthrough of catalyst dust into the second stage of the scrubber and further into the food compressor of the dehydrogenation unit, reducing the overhaul runs of the latter, which also leads to the accumulation of catalyst slurry in the cube scrubber of the second stage, pollutes the water in the upper circulation circuit, limiting the possibility of using the specified water as a coolant in circulating heat exchangers-coolers sludge water, leading to rapid clogging of the latter;

- a relatively high temperature of the contact gas after the scrubber - in front of the compressor - (50 ° C), which determines a large ablation of water vapor with the contact gas, which requires additional costs for subsequent condensation of water vapor before the contact gas is supplied to the compressor and, in addition, does not allow to carry out the work of the dehydrogenation unit at high loads of raw materials, helps to increase the pressure in the reactor, which reduces the yield of olefins on decomposed paraffins;

- a large specific water circulation per contact gas supplied (liquid / gas ratio), typical for used counterflow grating plates and associated with the “sewage” of liquid and gas flows in the scrubber, when the gas going upward passes through separate openings in the plate, while most of the downward flowing fluid passes through other openings without contact with the gas, which as a result leads to a low level of heat and mass transfer and an increased consumption of electricity on circulation pumps;

- in large-diameter scrubbers and at high gas scrubber loads characteristic of dehydrogenation processes, the use of failed plates also results in the appearance of large-scale irregularities, when the gas tends to go mainly through holes in the central part of the plates, while only liquid falls along the edges, which reduces the efficiency of heat and mass transfer in these scrubbers;

It is necessary to separately note the unreliability, inefficiency and technological dependence of the unit of evaporation of raw materials in the known method, when using hot technological water obtained as a coolant obtained at a plant that is part of another production. In this regard, as well as in connection with the closure of inefficient two-stage production of diene hydrocarbons, to date, olefin production plants are mainly based on the use of expensive water vapor as a coolant in raw materials.

The objective of the present invention is to increase the efficiency of heat and mass transfer in a disk scrubber, providing an increase in the degree of purification of the contact gas from the catalyst dust, lowering the temperature of the contact gas at the outlet of the scrubber, and obtaining clean hot water suitable for use as a coolant in surface heat exchangers, as applied to the requirements of the implementation processes for the production of olefinic hydrocarbons by dehydrogenation of the corresponding paraffinic hydrocarbons.

A dish scrubber, irrigated with water, is proposed for cooling and purifying contact gas in the processes for producing olefin hydrocarbons by dehydrogenation of the corresponding paraffin hydrocarbons, including a vertical cylindrical body 1, comprising a contact gas input unit located in the lower bottom of the body in the form of a central pipeline 2 with an upper edge located above its top 3 with a chipper 4, a blank plate 5, dividing the body of the scrubber 1 into the first stage of contacting of the contact gas 6 and supplied to the orosh a water scrubber in the lower part of the scrubber and the second stage 7 in its upper part and representing a horizontal partition with a glass 8 located in its central part along the axis of the housing 1, having a bump 10 along the contact gas above its upper edge 9, each step Contact 6, 7 has a circulation pipe 13, 16, equipped with a pump 11, 12 for independent circulation of water through these contact steps 6, 7, and the pipe 13 of the first stage 6 is connected to a pipe 14 located below the upper edge 3 of the contact gas inlet pipe 2, and with the circulating water inlet pipe 15 for irrigation of the first contacting stage 6, and the second stage 7 inlet pipe 16 is further provided with a circulating water heat exchanger-cooler 17 and connected to the pipe 18 located above the blank plate 5 below the upper edge 9 cup 8 and with a pipe 20 for introducing circulating water for irrigation of the second stage of contact 7 through the distributor 22, which also contains a spray catcher 23 installed in the upper bottom of the housing 1 and connected to the pipeline house 58 of the output of the contact gas from the scrubber, in which the first contacting stage 6 contains three annular, horizontally and sequentially along the contact gas perforated or grating plates - gas distribution 24 and two workers 25, 26 for contacting the contact gas and circulating water - with the ratio of free the sections of the plates, respectively, 1: (0.3-0.7) :( 0.15-0.5), while each of the working plates 25, 26 is non-failing for water and has a circulating water distribution device containing located in the peripheral part of the plate, an annular receiving pocket 27, 28 with an overflow threshold in the form of an annular vertical overflow partition 29, 30, the upper edge 35, 36 of which is located in a horizontal plane, for receiving circulating water and its distribution over the plate cloth, as well as the central part of the plates distribution boxes 31, 32 of cylindrical shape, the upper edges of which are in the horizontal plane and are located below or at the level of the upper edges 35, 36 of the annular overflow of the partition walls 29, 30, forming drainage thresholds, the distribution boxes 31, 32 having drainage pipes 37, 38, the lower ends 39, 40 of which are located below the upper edge 3 of the contact gas inlet pipe 2 below the water layer in the cubic part of the scrubber, while the circulation pipe of the first contact stage 6 is connected to a pipe 15 located in the receiving pocket 27 of the lower working plate 25, and the scrubber has one or more overflow pipes 44, 45 located outside or inside the scrubber body 1, and these upper ends 46, 47 are pipes are located below the upper edge 9 of nozzle 8 hollow plates 5 and the lower ends - the receiving pocket 28 in the upper working plates 26 or above. In this case, the upper end 47 of the overflow pipe 45, located inside the scrubber body 1, is equipped with a cap that creates a water seal 56 when overflowing water from the second contact stage 7.

In this case, overflow partitions 29, 30 of the “comb” type can be used with the top edge 35, 36 in the form of slots having the shape of a rectangle or triangle with the apex pointing downward, the lower edges of the slots being in the horizontal plane.

The gas distribution grill 24 may have a circular shape and occupy the entire cross section of the scrubber.

The circulation pipe 13 of the first stage of contact 6 can additionally be connected to the pipes 41 located in the receiving pocket 28 of the upper work plate 26.

The second contacting stage 7 preferably contains 4-12 perforated or lattice failure plates 48 without an overflow device with a free cross section of 0.15 to 0.5 with countercurrent movement of circulating water and contact gas in the plate openings.

The second contacting stage 7 may consist of at least two sections 49, 50, each of which has at least one plate, while the upper section 49 has a water supply distributor 22 for irrigation of the entire surface of the plates of the specified section, and each lower section 50 has a feed distributor water 21 for irrigation of the central part of the plates of this section, comprising from 10 to 50% of the total area of the plates. The water distribution valves 21, 22 in the indicated sections 49, 50 can be connected to the circulation pipe 16 of the second contact stage 7 after the heat exchanger-cooler 17. In this case, the upper section 49 can have a free section of plates 48 from 0.15 to 0.4, and the lower sections 50 - from 0.2 to 0.5.

The second contacting stage 7 may comprise a regular packing layer or comprise a combination of a plate pack and packing.

Pipes 51 for measuring the water level in the lower part of the scrubber body can be located below the bump 4 of the central contact gas inlet pipe 2.

In the lower part of the scrubber body 1, pipelines with nozzles can be arranged for withdrawing slurry water for treatment 54 and returning clarified water 55 to the system.

In the upper part of the scrubber body 1 above the blank plate 5, a nozzle 59 can be located for feeding the scrubber with fresh water.

As a heat exchanger-cooler 17 can use a refrigerator cooled by industrial circulating water, or an evaporator of liquid raw materials with a further supply of the resulting vapor of paraffin hydrocarbons for dehydrogenation.

The main differences of the proposed plate scrubber from the prototype are.

1. The use in the first stage of contacting a combination of three plates with the claimed ratio of their free cross-section with successive passage of contact gas through them:

- “dry” gas distribution plate;

- non-failing working plate with an overflow device, irrigated by a stream of contaminated water circulating in the first stage, operating in a "foam" mode;

- non-failing working plate with an overflow device, irrigated by the flow of part of the pure water circulating in the second stage, operating in the "foam" mode.

2. The ability to regulate the operation mode of the upper plate of the first contacting stage by additional supplying part of the circulation water of the first stage to its irrigation.

3. Separation of a package of failed plates without overflow devices in the second stage of contacting into sections using a water distributor irrigating the entire surface of the plates of the upper section and distributors irrigating only the central part of the surface of the plates in the lower sections.

4. The proportion of the free section of the plates, varying in height of the second stage of contacting, is such that the proportion of the free section of the plates of the lower sections is greater than the fraction of the free section of the plates of the upper sections. This allows you to work with irrigation density varying in height (t / m ² hours) - with an increase in irrigation density along the height of the scrubber from top to bottom in accordance with paragraph 3 (see above).

The technical result of the proposed solution is to increase the efficiency of heat and mass transfer in a disk scrubber, provide an increase in the degree of purification of contact gas from catalyst dust, lower the temperature of the contact gas at the outlet of the scrubber, and obtain clean hot water suitable for use as a coolant in surface heat exchangers, as applied to the requirements the implementation of processes for the production of olefinic hydrocarbons by dehydrogenation of the corresponding paraffinic hydrocarbons.

The proposed dish scrubber can be used in the production of olefin hydrocarbons by dehydrogenation of the corresponding paraffin hydrocarbons, as well as for the interaction of gas and liquid in various processes of the petrochemical and chemical industries.

In FIG. 1 shows a diagram of the inventive plate scrubber for cooling and purifying contact gas from catalyst dust in the processes of producing C ₃ -C ₅ olefinic hydrocarbons by dehydrogenation of the corresponding paraffin hydrocarbons in a fluidized bed of a fine-grained alumina-chromium catalyst.

The plate scrubber comprises a vertical cylindrical body 1 located in the lower bottom of the body 1, a contact gas input unit in the form of a central pipeline 2 with a baffle 4 located above its upper edge 3, a blank plate 5 dividing the body of the scrubber into a first contact gas and water contact stage 6 in the lower part of the scrubber and the second stage 7 in its upper part. The blank plate 5 is a horizontal partition with a glass 8 located in its central part along the axis of the housing 1, having a bump 10 along the contact gas above its upper edge 9. Moreover, both contacting stages have circulation pipelines 13, 16 equipped with pumps 11 and 12 for independent circulation of water through these stages of contacting, and the pipe 13 of the first stage of contacting 6 is connected to a pipe 14 located below the upper edge 3 of the Central pipeline of input gas 2, and with patr ubcom 15 of the input of circulating water for irrigation of the first stage of contact 6, and the pipe 16 of the second stage of contact 7 is additionally equipped with a heat exchanger-cooler of circulating water 17 and is connected to the pipe 18, located above the blank plate 5 below the upper edge 9 of the glass 8 and with pipes 19 and 20 for introducing circulating water for irrigation of the second stage of contacting 7. The scrubber also contains a spray trap 23 installed in the upper bottom of the housing 1, connected to a nozzle 58 for withdrawing contact gas from the scrubber.

The first contacting stage 6 contains three perforated or grating plates arranged sequentially along the contact gas — gas distribution 24 and two working 25 and 26 for contacting the contact gas and circulating water, while both working plates 25,26 have circulating water distribution devices containing the peripheral part of the plates, annular receiving pockets 27 and 28 with overflow thresholds in the form of vertical overflow partitions 29 and 30, the upper edges of which 35 and 36 are located in horizontal plane, for the reception of circulating water and its distribution on the canvas ring-shaped, located horizontally plates. The upper edges 35, 36 of the overflow partitions 29, 30 are made in the form of a “comb”, in the form of slots having the shape of, for example, a rectangle or triangle with a vertex pointing downward, with the lower edges of the slots being in the horizontal plane. In FIG. 1 shows the slots in the form of triangles. The preferred use of slots is when the flow rate is from 1 to 11 m ³ / hour per 1 m of the length of the partition. In the central part of the plates, there are cylindrical distribution boxes 31 and 32, the upper edges of which 33 and 34 are in the horizontal plane and are located below the upper edges of the overflow partitions 35 and 36, respectively, forming drainage thresholds, and the distribution boxes 31, 32 have drain pipes 37 and 38 the lower ends 39 and 40 of which are located below the upper edge 3 of the central pipeline for inputting contact gas 2, while the circulation pipe 13 of the first contacting stage 6 is connected through valves 42 and 43 to tubes 15 and 41 located in the receiving pockets 27 and 28 of the lower 25 and upper 26 working plates. The scrubber has one or more overflow pipes 44 located outside the scrubber body 1 and / or overflow pipe 45 with a water trap 56 located inside the body 1, the upper ends of these pipes 46 and 47 located below the upper edge 9 of the glass 8 of the blank plate 5, and the lower ends - in the receiving pocket 28 of the upper working plate 26 or above it.

The second contact stage 7 contains six perforated or lattice failure plates 48 without overflow devices with countercurrent movement of circulating water and contact gas in the holes of the lattices and consists of two sections 49 and 50, each of which has three plates with the same free section, with the upper section 49 contains plates with a free section, the value of which is, for example, 0.2 of the total surface of the plates and has a distributor 22 for supplying water for irrigation of the entire surface of the upper plate is indicated section, and the lower section 50 contains plates with a free section, for example, 0.3 and has a distributor 21 for supplying water for irrigation of the central part, comprising, for example, 40% of the area of the upper plate of this section, while the water supply distributors 21, 22 in the indicated sections 49, 50 are connected to the circulation pipe 16 of the second contact stage 7 after the heat exchanger-cooler 17 (evaporator of raw materials or a refrigerator cooled by recycled industrial water) through valves 52 and 53.

The second contacting stage 7 may comprise a layer of a regular nozzle (not shown in FIG. 1) or include a combination of a plate pack 48 and nozzles.

Below the chimney 4 of the central contact gas inlet pipe 2 there are pipes 51 for measuring the water level in the lower part of the scrubber body.

The circulation pipe 13 of the first contact stage 6 is connected to the pipe with a pipe 54 for outputting slurry water for cleaning. The scrubber has a pipe with a nozzle 55, preferably in its bottom part, to return clarified water to the system. In the upper part of the housing 1 above the blank plate 5 there is a pipe 59 for feeding the scrubber with fresh water. A pipe 61 is provided for draining the system. Position 62 indicates the water level in the cubic parts of the scrubber and on the plates of the second stage of contact 7.

The proposed dish scrubber operates as follows.

The contact gas of isobutane dehydrogenation enters the disk scrubber through the central pipe 2, is distributed by the chipper 4 along the cross section of the scrubber, passes sequentially the plates 24, 25 and 26 in the first stage 6 of contacting gas and irrigation water and then through the glass 8 of the blank plate 5 enters the second stage contacting 7, where it is distributed over the cross section of the scrubber by the chipper 10, sequentially passes through sections 49, 50 of the plates 48 and, then, through the spray catcher 23 and the pipe 58 is sent to the condensation stage and Highlighted isobutylene.

Circulating water of the first contacting stage 6 is taken from the water layer in the cubic part of the scrubber through the pipe 14, is sent by the pump 11 through the pipe 13 to irrigate the plate 25 through the control valve 42, pipe 15 and enters the annular receiving pocket 27 of the plate 25. From the water layer above the deaf with a plate 5, water from the second contacting stage 7 spontaneously enters through drain pipes 44 or 45 into an annular receiving pocket 28 to irrigate the upper plate 26. Water entering the receiving pocket 28 through the drain pipe 45 passes through the gate 56 and flows onto the wall of the scrubber body 1 above said receiving pocket 28, then flowing down into the receiving pocket. If necessary, in order to regulate the operation mode of the upper plate 26, a part of the circulating water of the first contacting stage 6 can be additionally supplied to the receiving pocket 28 through a pipe 13, through a valve 43 and a pipe 41. Water flows supplied to the receiving pockets 27 and 28 at the periphery of the plates through the annular overflow thresholds - the upper edges 35 and 36 of the overflow partitions 29 and 30 evenly irrigate the plates 25 and 26, the plates pass in a radial direction, cross to the flow of contact gas, and through the drain thresholds formed by the upper the edges 33 and 34 of the distribution boxes 31 and 32 and, further, through the drain pipes 38 and 37 enter the level of the water layer in the bottom part of the scrubber. The upper plates 25 and 26 operate in foam mode, i.e. with intensive turbulization of a gas-liquid system with its transformation into a mobile unstable, and dynamically stable foam due to the kinetic energy of the gas. In the claimed range of ratios of the free section of the plates, with the claimed location of the drain pipes 37, 38, distribution boxes 31, 32, plates 25 and 26 operate in non-water mode, and the lower plate 24 is conditionally “dry” and works as a distribution for contact gas .

Circulating water of the second contact stage 7 is taken from the water layer above the blank plate 5 through the pipe 18 and sent by the pump 12 to the heat exchanger-cooler (evaporator of raw materials) 17, where it is cooled by evaporation of the liquid raw material supplied to the heat exchanger-cooler (evaporator) 17 through pipeline 57 with further supply through the pipeline of 60 produced vapors of paraffin hydrocarbons for dehydrogenation. Further, the circulating water through the pipeline 16 is directed to irrigation of the upper plate of the upper section of the plates 49 through the control valve 53, the pipe 20 and the distributor 22, equipped with nozzles providing irrigation of the entire surface of the plate. While circulating water can also be supplied when regulating the operation of the section 50 of the plates 48 through the control valve 52, the pipe 19 and the distributor 21, equipped with nozzles for irrigation of the Central part of the plates of the lower section, which is part of the total area of the plate.

The specified combination of the claimed design parameters and operating modes of the plates of the first contacting stage 6, the foam mode of the working plates, as well as the organization of irrigation of the working plates (irrigation of the lower working plate with contaminated water from the cube of the first contacting stage 6 and irrigation of the upper working plate with clean water from the cube of the second contacting stage 7) provides a higher level of heat and mass transfer and dust collection efficiency, with fewer plates and less water circulation in the first contact stage ation 6 in comparison with the prototype.

Separation of the plates of the second contacting stage 7 into sections 49, 50 so that the free section of the plates 48 in the upper section 49 is less than in the lower section 50 and the upper section 49 has a water distributor 22 that irrigates the entire surface of the plates of the indicated section, and the lower one irrigates only the central part of the plates of this section leads to the alignment of the water layer on all the plates of the second contacting stage 7, prevents the predominant passage of gas in the central part of the plates 48, eliminates the "sewage" of flows through the plates 48, when It also leads to an increase in the ratio of the amount of water supplied for irrigation to the amount of contact gas supplied from the upper section 49 to the lower 50 and creates conditions under which uniformity of hydraulic resistance is maintained over the entire surface of each plate of the second stage 7. All this increases the heat and mass transfer on the plates of the second contact stage 7 and allows to reduce the number of plates 48 in the specified stage of the scrubber. The achieved purity of water in the second stage of contacting 7 allows you to use a layer of a regular nozzle in this stage or contain a combination of a package of plates and nozzles.

Table 1 shows the composition of the contact gas of isobutane dehydrogenation supplied to the scrubber.

Tables 2 and 3 show the performance of a plate scrubber according to the prototype and according to the invention in the process of producing isobutylene by isobutane dehydrogenation in a fluidized bed of finely dispersed aluminum-chromium catalyst AOK 73-24 with the latter circulating in the reactor-regenerator system. The installation includes the preparation of a mixture of fresh and recycle isobutane streams, its evaporation in a heat exchanger-evaporator, heating of the vapors due to the heat of contact gas in the quenching coils of the reactor and their overheating in the furnace before being fed to dehydrogenation, purification of contact gas in cyclones located inside the separation zone reactor, cooling the dehydrogenation contact gas in waste heat boilers to produce water vapor, as well as cooling and cleaning the contact gas in a two-stage scrubber irrigated with water divided by a blank plate 5 into the first stage of cooling and cleaning in the lower part of the scrubber with the lower water circuit and the second stage in its upper part with the upper water circuit having a water-cooler heat exchanger 17, subsequent compression of the cooled contact gas, condensation and fraction separation isobutane and isobutylene from hydrocarbon condensate by distillation with the supply of the isolated isobutane to recycling, and isobutylene for purification and use as intended.

In examples of using a disk scrubber according to the prototype and according to the invention, for the possibility of a comparative analysis, the maximum possible compliance with the same process conditions was carried out, including the same feed rate of 27 t / h (table 3). The amount of contact gas indicated in the tables takes into account additional auxiliary flows supplied to the dehydrogenation system.

Example 1 (prototype).

The diameter of the scrubber body is 3.2 m.

The height of the cylindrical part of the scrubber body is 16 m. The number of trellised plates:

- in the first stage of contacting - 4 pcs;

- in the second stage of contacting - 8 pcs.

Free section of plates:

- in the first stage of contacting - 0.24 m ² / m ² ;

- in the second stage of contacting - 0.20 m ² / m ² .

As a heat exchanger-cooler circulating in the second stage of water contacting, a refrigerator is used, cooled by recycled industrial water.

Characteristics of the refrigerator cooler:

- heat transfer surface - 534 m ² ;

- case diameter -1 m; - tubes 25 × 2.5 × 6000 mm;

- the number of tubes 616 pcs;

- number of heat exchangers - 2 pcs.

As a heat exchanger-evaporator for the evaporation of isobutane, a shell-and-tube heat exchanger is used, which is heated by steam (13 ata).

Heat exchanger-evaporator characteristic:

- heat transfer surface - 149 m ² ;

- case diameter - 0.8 m;

- tubes 25 × 2 × 4000 mm;

- number of tubes - 475 pcs.

The circulation water from the cube of the second stage scrubber is directed at a temperature of 59.2 ° C into the tube space of a heat exchanger-cooler cooled by recycled industrial water. In this case, clogging of the heat exchange surface of the heat exchanger with catalyst deposits is observed. After the installation is started, the temperature of the circulation water after the heat exchanger rises rapidly from 35 ° C to 45 ° C, which leads to an increase in the temperature of the contact gas after the scrubber to 50 ° C. Periodic cleaning of the heat exchanger is required. An additional connection of an air cooler on the circulation water line is also used. The evaporation of paraffin hydrocarbons in a dehydrogenation unit is carried out in a heat exchanger-evaporator heated by steam. The catalyst trapped in the scrubber with high-boiling hydrocarbons in the form of resins adsorbed on it is removed by draining the cubes of the first and second stage scrubber with the separation of the resulting catalyst slurry in the sumps when the clarified water is returned to the cube of the first stage of the scrubber.

The main results of using a disk scrubber according to the prototype are presented in table 2.

Example 2 (according to the invention).

Some conditions for the implementation of the process are shown in example 1.

The total number of plates in the scrubber is 9 pieces;

The number of perforated plates in the first stage of contacting - 3 pcs;

The number of trellised plates in the second stage of contacting is 6 pieces;

The number of sections in the second stage of contacting - 2 pcs;

The number of plates in the section - 3 pcs;

Free section of plates:

- gas distribution of the first stage of contacting - 0.4;

- lower working of the first stage of contacting - 0.21;

- the upper working of the first stage of contacting - 0.17;

- the ratio of the free section of the plates of the first stage: 1: 0.525: 0.425;

- the upper section of the second stage of contacting - 0.2;

- lower section of the second stage of contacting - 0.3;

The irrigation area of the plates of the second stage:

- upper section - 100%;

- lower section - 40%.

Cooling and cleaning of the contact gas in the first stage 6 of the scrubber is carried out in the mode of contact gas quenching from the initial temperature of 250 ° C to 74 ° C by evaporation of 6.14 tons / hour of water circulating in the lower circuit, and in the second stage 7 in the mode condensation of water vapor supplied with the contact gas through a blank plate 5 from the first stage 6 of the scrubber. In this case, the balance amount of water equal to the amount of water condensate obtained in the second stage 7, taking into account the balance of ablation of water vapor with contact gas, production losses and replenishment of the scrubber with fresh water, is directed by gravity from the cube of the second stage 7 of the scrubber through the upper end 47 of the overflow pipe 45 for irrigation of the upper working plate 26 of the first contacting stage 6 in addition to the portion of the circulating water of the first stage 6 of the scrubber supplied through the valve 43 in an amount of 20 t / h. The circulation water from the cube of the second stage 7 at a temperature of 51.8 ° C is sent as a coolant to a heat exchanger-cooler (evaporator) 17 for evaporation of paraffin hydrocarbons, after which it is returned to the scrubber for irrigation of the second stage 7, cooled to 35 ° C. The temperature of the contact gas at the exit of the scrubber is 40 ° C.

In order to avoid the accumulation of catalyst dust in the second-stage circulating circuit, part of the water in an amount of 5-6 t / h is constantly discharged to the sump (not shown in Fig. 1) after which the clarified water is returned to the scrubber. The catalyst trapped in the scrubber with high-boiling hydrocarbons in the form of resins adsorbed on it can also be removed from the cube of the first stage 6 scrubber with the separation of the resulting catalyst slurry in filters or centrifuges when the clarified water is returned to the cube of the first stage 6 of the scrubber. The concentrated catalyst sludges obtained during the dehydrogenation process are sent, for example, to combustion by known methods in the combustion zone of gas fuel in a fluidized bed of a regenerator of a dehydrogenation unit (not shown in Fig. 1).

The thermal potential and purity of the circulating water of the second contacting stage 7 is sufficient for use as a coolant in the raw material evaporator. The circulation water was supplied to the tube space of the evaporator. During the year of continuous run of the dehydrogenation unit, there were no signs of clogging of the heat exchange surfaces of the raw material evaporator. When using version 17 as a heat exchanger-cooler with a refrigerator cooled by industrial recycled water when circulating water is supplied to the pipe space, no clogging of the refrigerator is also noted.

The main results of using a disk scrubber according to the invention are shown in table 3.

As can be seen from the data presented in tables 2, 3, when using the proposed plate scrubber in the variant of supplying the hot water obtained in the scrubber to evaporate the dehydrogenation feedstock (isobutane) in comparison with the prototype, the following is achieved:

- heat exchanger-cooler 17, cooled by recycled industrial water, is taken out of operation, while the consumption of cooling recycled water in the amount of 5.3 tons per ton of feed is excluded;

- there is no need to use an air-cooled heat exchanger for cooling the circulating water with the corresponding energy savings;

- stops the use of water vapor supplied in the prototype for the evaporation of isobutane in the amount of 0.19 tons per ton of feed;

- 1.76 times reduced ablation from the scrubber of water vapor with contact gas, which accordingly reduces the cost of further condensation of water vapor from the contact gas stream and purification of the resulting condensate, and also reduces the scrubber replenishment with fresh water.

- no less than an order of magnitude decrease in the entrainment of the catalyst at the outlet of the contact gas from the scrubber;

- the amount of water circulation in the first stage of the scrubber decreases by 1.4 times, and, accordingly, the energy consumption on the circulation pumps.

The proposed plate scrubber can also be used to design new and modernize other large-scale chemical processes in the industry, such as catalytic cracking, synthesis of nitrile acrylic acid (NAC), and the preparation and processing of various dispersed materials.

Claims (13)

1. A plate scrubber for cooling and purification of contact gas in the processes of producing olefin hydrocarbons by dehydrogenation of the corresponding paraffin hydrocarbons, including a vertical cylindrical body (1) containing a contact gas inlet unit located in the lower bottom of the body in the form of a central pipeline (2) with an upper one edge (3) with a chipper (4), a blank plate (5) dividing the scrubber body (1) into the first stage of contacting the contact gas (6) and the water supplied to the scrubber for irrigation the bottom of the scrubber and the second stage (7) - in its upper part, and representing a horizontal partition with a glass (8) located in its central part along the axis of the housing (1), having a chipper along the contact gas above its upper edge (9) (10), while each contacting stage (6), (7) has a circulation pipe (13), (16) equipped with a pump (11), (12) for independent water circulation through the indicated contacting stages (6), (7) ), and the pipeline (13) of the first stage (6) is connected to a pipe (14) located below the upper edge (3) a central pipeline (2) for introducing contact gas, and with a pipe (15) for introducing circulating water for irrigation of the first contacting stage (6), and the pipeline (16) of the second stage (7) is additionally equipped with a heat exchanger-cooler (17) of circulating water and connected to a pipe (18) located above the blank plate (5) below the upper edge (9) of the glass (8), and to a pipe (20) for introducing circulating water for irrigation of the second contact stage (7) through a distributor (22), in the upper bottom of the housing (1) has a spray trap (23) connected to the nozzle (58) withdrawing the contact gas from the scrubber, characterized in that the first contacting stage (6) contains three annular, perforated or grating plates arranged horizontally and sequentially along the contact gas - gas distribution plates (24) and two workers (25), (26) for contacting the contact gas and the circulating water, with the ratio of the free section of the plates, respectively, 1: (0.3-0.7) :( 0.15-0.5), with each of the working plates (25), (26) being non-dip for water and has a circulating switchgear water containing an annular receiving pocket located in the peripheral part of the plate (27), (28) with an overflow threshold in the form of an annular vertical overflow partition (29), (30), the upper edge (35), (36) of which is located in the horizontal plane , for the reception of circulating water and its distribution over the plate cloth, as well as distribution boxes (31), (32) of a cylindrical shape located in the central part of the plates, the upper edges (33), (34) of which are in the horizontal plane and are located below or on level not the upper edges (35), (36) of the annular overflow partitions (29), (30), forming drainage thresholds, the distribution boxes (31), (32) having drainage pipes (37), (38), the lower ends (39 ), (40) which are located below the upper edge (3) of the central pipeline (2) of the contact gas inlet below the level of the water layer in the bottom part of the scrubber, while the circulation pipe (13) of the first contacting stage (6) is connected to the pipe (15), located in the receiving pocket (27) of the lower working plate (25), as well as the scrubber has one or more overflow pipes (4 4), (45) located outside and / or inside the body (1) of the scrubber, the upper ends (46), (47) of these pipes are located below the upper edge (9) of the glass (8) of the blank plate (5), and the lower ends - in the receiving pocket (28) of the upper working plate (26) or above it, while the upper end (47) of the overflow pipe (45) located inside the scrubber body (1) is equipped with a cap that creates a water lock (56) when overflowing water from the second stage of contacting (7). 2. A plate scrubber according to claim 1, characterized in that the overflow partitions (29), (30) of the “comb” type are used with the upper edge (35), (36) in the form of slots having the shape of a rectangle or triangle with the vertex directed down, and the lower edges of the slots are in the horizontal plane. 3. Dish scrubber according to any one of paragraphs. 1, 2, characterized in that the gas distribution grill (24) has a circular shape and occupies the entire cross section of the scrubber. 4. Plate scrubber according to any one of paragraphs. 1-3, characterized in that the circulation pipe (13) of the first contacting stage (6) is additionally connected to the nozzles (41) located in the receiving pocket (28) of the upper working plate (26). 5. Plate scrubber according to any one of paragraphs. 1-4, characterized in that the second contacting stage (7) contains 4-12 perforated or lattice failure plates (48) without an overflow device with a free cross-section from 0.15 to 0.5 with counter-current movement of circulating water and contact gas in plate openings. 6. A plate scrubber according to claim 5, characterized in that the second contacting stage (7) consists of at least two sections (49), (50), each of which has at least one plate, while the upper section (49) has a water supply distributor (22) for irrigation of the entire surface of the plates of the indicated section, and each lower section (50) has a water supply distributor (21) for irrigation of the central part of the plates of this section, comprising from 10 to 50% of the total area of the plates, while the feed distributors water (21), (22) in the indicated sections (49), (50) are connected to the circulator onnym conduit (16) contacting the second stage (7) after the heat exchanger-cooler (17). 7. A plate scrubber according to claim 6, characterized in that the upper section (49) has a free section share of the plates (48) from 0.15 to 0.4, and the lower sections (50) from 0.2 to 0.5 . 8. Plate scrubber according to any one of paragraphs. 1-4, characterized in that the second stage of contacting (7) contains a layer of regular packing. 9. Dish scrubber according to any one of paragraphs. 1-4, characterized in that the second stage of contacting (7) contains a combination of a package of plates and nozzles. 10. Dish scrubber according to any one of paragraphs. 1-9, characterized in that below the bump (4) of the Central pipeline for contact gas (2) are pipes (51) for measuring the water level in the lower part of the scrubber body. 11. Dish scrubber according to any one of paragraphs. 1-10, characterized in that in the lower part of the scrubber body (1) there are pipelines with nozzles for withdrawing slurry water for treatment (54) and returning clarified water (55) to the system. 12. Plate scrubber according to any one of paragraphs. 1-11, characterized in that in the upper part of the scrubber body (1) above the blank plate (5) there is a pipe (59) for feeding the scrubber with fresh water. 13. Dish scrubber according to any one of paragraphs. 1-12, characterized in that as a heat exchanger-cooler (17) use a refrigerator cooled by industrial circulating water, or an evaporator of liquid raw materials with a further supply of the resulting vapor of paraffin hydrocarbons for dehydrogenation.

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