RU2562482C1 - Fractionator - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: fractionator comprises housing with sprinkling, stock feed union and steam from boiler or hot jet from furnace, with unions for discharge of stillage bottoms, top and side products, systems of temperature, pressure, flow rate and quality metering systems, manways and heat exchange sections accommodating contact device of adapter- and/or plate crossed-flow type with drain webs, pockets and overflow pipes. In the case of multiflow contact devices with different number of flows, contact devices accommodate the condensate collector communicated with overflow pipes of underlying contact device and communicated with condensate distributor at underlying contact device.

EFFECT: higher efficiency.

14 cl, 3 dwg

Description

The invention relates to mass transfer equipment for liquid-gas (steam) systems and can be used to implement rectification, distillation and absorption separation processes in the oil refining, gas processing, chemical, food and other industries.

Numerous designs of fractionation apparatuses are known, including a housing equipped with fittings for introducing raw materials, irrigation, vapors from a boiler or a hot stream from the furnace, output of still, top and side products, temperature, pressure, flow and quality measuring systems, manholes and mass transfer sections, in which contact devices of a packed and / or cross-type disk type with drain partitions, pockets and transfer pipes are placed (Alexandrov I.A. Rectification and absorption apparatus . Methods of analysis and design of foundations. M .: Chemistry, 1965. 308 pp.). A common drawback of these designs is the lack of versatility, since for specific production situations it is necessary to develop new designs of fractionating apparatuses, for example, when the loads of contact devices in the liquid phase are high or change sharply in height of the fractionating apparatus in the fractionating apparatus.

A distillation column is known, for example, containing a set of fractionation plates made in the form of a closed cylindrical outer column having a) upper and lower end parts and a cylindrical inner surface, b) upper first and lower second fractionation plates of the same design, and the fractionation plates have a drain a channel that has a side wall extending outward from the contact area of the vapor — liquid formed by the overlap, the upper first plate being supported in place Inside the column a second bottom plate and the bottom plate with the second support pillar attached to the outer column. (A distillation column containing a set of fractionation plates, a set of fractionation plates for installation in a fractional distillation column, and a method for installing plates in a fractional distillation column: RF application 2000119917; July 25, 2000; publ. June 27, 2002.) The disadvantage of this invention is the formation of a set of plates of two plates, in which only the lower plate is hermetically mating with the column body, and the perforated overlap of the upper first plate has a substantially circular periphery that is separated from the inner the surface of the column with an unsealed annular gap that allows liquid to pass downward from overlapping the upper first plate to the lower second plate, while a bypass slip of part of the steam flow from the second plate to the vapor space above the first plate is possible, which will reduce the mass transfer efficiency and the efficiency of the first set plate . In addition, with an increase in the flow of the liquid phase (reflux) on the second plate due to the intense condensation of vapors on the first plate, the flow rate of the liquid phase on the first plate will increase sharply, which will lead to a decrease in the contact time between the vapor and liquid phases on the second plate and indirectly decrease the efficiency of the second plate of the kit.

Known distillation column, which has an inner wall and contains many horizontally located one above the other perforated fractionation plates, including the first perforated fractionation plate with at least one drain cup adjacent to the periphery of the plate, for channeling the output stream from the first plate through at least one radially located outlet channel to the second perforated fractioning plate located directly underneath a ditch plate, wherein said second plate contains a zone under the drain cup located immediately below the drain cup from the first fractionation plate, characterized in that the outlet channel of each drain cup is arranged so that the outlet stream from it initially flows exclusively in the direction of the inner wall of the column, adjacent to the drain cup, and at least one portion of the zone under the drain cup has many perforations, while there is a perforated barrier between the perforated Anna zone and a second perforated plate of the initial contact zone the liquid flowing from the downcomer. (Distillation column: Pat. 2172203 of the Russian Federation. No. 99117147/12; claimed. 01/27/97; publ. 08/20/01.) The disadvantage of this invention is a significant difference in the levels of the liquid phase along the flow path of the liquid phase along the plate cloth, while under the drain With a glass, the level of the liquid phase is much higher than on the opposite side of the plate cloth, where a minimum pressure drop will be formed for the vapor phase to pass and channels can be formed in the liquid through which the vapor phase will pass without contact with the liquid phase, and under the drain glass is the maximum level of the liquid phase will be formed and the maximum pressure drop for the passage of the vapor phase and as a result, the possibility of reducing the steam consumption to zero, which would reduce the mass transfer efficiency in these areas plates and reduce the efficiency of the dish as a whole.

There is also known an apparatus in which contact devices are a small-louvered plate with chippers for heat and mass transfer processes, including a receiving pocket, horizontal pro-thinned cloths of the base of the dish, a drain pocket, chippers above the cloths of the dish base, with perforated material being used as the materials of the dish base and chippers the canvas and additionally contains a chipper in the drain pocket. (Small-louvre plate with chippers: certificate No. 1288831 of the Russian Federation. No. 2012147144/05; filed November 6, 2012; published on June 10, 2013.) The disadvantage of this invention is that the use of chippers from a perforated sheet, directed smooth side towards the movement of the liquid, located above the plates of the base of the plate and in the drain pocket, contributing to the intensive separation of the vapor-liquid flow generated during the operation of the plate, at the same time reduce the contact time of the vapor bubbles and the liquid phase of the vapor-liquid flow, which will lead to a decrease iju mass transfer efficiency in the vapor - liquid system and reduce the efficiency of the dish as a whole. In addition, chippers represent additional hydraulic resistance during the movement of the liquid phase flow (phlegmy) along the plate, which leads to a gradual increase in steam flow through the perforated plate from the beginning to the end of the plate blade along the flow movement, which leads to a parabolic law of the change in the local efficiency fragments of a perforated plate with a decrease in the efficiency at the beginning and end of the plate and to reduce the efficiency of the plate in th. Another disadvantage of the apparatus with small-louvered plates is the constancy of the number of flows on adjacent plates, which does not allow to optimize the mass transfer process with a significant change in the amount of flow of the liquid phase (reflux) along the height of the column.

When creating the invention, the task was to develop a highly efficient fractionating apparatus used in the case when the load of the contact devices in the fractionating apparatus is high or dramatically changes in height in the liquid phase and / or vapor phase. Such devices include the following:

- columns stabilizing gasolines and oils with a significant change in the amount of vapor and liquid phases in the upper and lower parts of the column;

- distillation columns with circulating irrigation, significantly increasing the load of the contact devices in the liquid phase in the zone of circulating irrigation;

- distillation columns for separating multicomponent mixtures with a significant difference in the concentrations of the components in the feedstock, for example, when separating a three-component mixture with a low content of low boiling and high boiling components, when the low boiling component is separated as distillate, the contact devices at the bottom of the fractionating apparatus will be overloaded under reflux, and when high-boiling component is selected as the remainder, the contact devices at the top of the fractionating apparatus will be overloaded downstream of the reflux;

- absorption columns for cleaning a gas stream with a high concentration of absorbable impurities, such as ammonia, with a small amount of effective absorbent, when the gas flow sharply decreases from bottom to top and the flow rate of saturated absorbent increases.

The designs of fractionation apparatuses, in which, according to their working conditions, it is necessary to use multi-threaded contact devices with different flow rates of adjacent contact devices (for example, two- and three-flow, four- and three-flow).

The problem is solved due to the fact that in the fractionating apparatus, which includes a housing equipped with fittings for introducing raw materials, irrigation, vapors from a boiler or hot stream from the furnace, withdrawal of bottoms, top and side products, measuring systems for temperature, pressure, flow and quality, hatches - manholes and mass transfer sections, in which contact devices of a nozzle and / or plate cross-type type with drain partitions, pockets and transfer pipes are placed, with multi-threaded design of contact devices In a space with a different number of flows on adjacent contact devices in the space between contact devices with multi-threaded (even and odd) versions of contact devices, a phlegm collector is placed that communicates with transfer pipes of the overlying contact device and communicates with overflow pipes with a reflux distributor to the underlying contact device, while in the case of the presence of circulating irrigation in the fractionating apparatus of the nozzle of input and output of circulating irrigation are communicated with the corresponding sat Orniki phlegm. In this case, by varying the number and cross-sectional area of the transfer pipes into the phlegm collector, it is possible to collect a liquid phase stream flowing down from the overlying contact device regardless of the number of flows on this contact device, and from the phlegm collector, the collected liquid can be sent to the phlegm distributor on the underlying contact the device is already independent of the number of threads on this contact device. At the same time, to create a hydraulic shutter when the phlegm flows from the overlying contact device to the underlying contact device, the phlegm collector has a phlegm collection section and a phlegm drain section separated by a drain wall, the phlegm reflux drain section is connected to the overflow pipes of the overlying contact device, and the phlegm collection section is communicated with a phlegm distributor on the underlying contact device using overflow pipes.

The systems for measuring temperature, pressure, flow rate and quality of the selected products are respectively temperature measurement sensors (thermocouples) installed in the positions of the apparatus body that determine the temperature regime of the fractionating apparatus, a pressure measurement sensor (manometer) installed in the upper part of the apparatus body, flow measurement sensors introduced and selected products (diaphragms) installed on pipelines connected to the corresponding fittings for input and output of these products from the housing apparatus, sensors for measuring the quality of selected products (flow-type or periodic samplers connected to quality analyzers) installed on the appropriate fittings of the apparatus body; analog indicators of temperature, pressure, flow rate and quality of the selected products are sent through the controller to an analog-to-digital converter and then to a computer that records the corresponding indicators and to instrumentation that registers and regulates the technological process.

It is advisable that the phlegm distributor in the form of a comb or ring collector be low-pressure to reduce the necessary free space between adjacent contact devices. The collector form of the reflux distributor provides reflux to the desired locations of the pockets of the underlying multi-threaded contact device, regardless of the number of flows of the underlying contact device. The most rational implementation of the phlegm dispenser in the form of a comb or ring collector allows the phlegm flows to be supplied to the necessary places of the underlying contact device, this is especially important for packed contact devices.

In cases where, according to the technological conditions, the number of flows at two adjacent contact devices is different, and the steam and reflux streams vary slightly along the height of a fragment of the fractionating apparatus, it is advisable that for two adjacent contact devices the combined cross section of overflow pipes was equal to the combined cross section of transfer pipes , which corresponds to the constancy of the reflux rate on two adjacent contact devices along the height of the apparatus during the transition from the overlying contact device to the bottom aschemu contact device.

In cases where, according to the technological conditions, the number of flows on two adjacent contact devices is different, for example, for significantly varying reflux flows along the height of a fragment of a fractionating apparatus, it is advisable that for two adjacent contact devices the ratio of the product of the total cross section of overflow pipes by the reflux flow rate in overflow pipes to the product of the total cross-section of the transfer pipes by the reflux flow rate in the transfer pipes was equal to the ratio of the reflux costs d vuh adjacent contact devices.

It is advisable, in the case of circulating irrigation in the fractionating apparatus, that the inlet of the circulating irrigation inlet communicates with the corresponding reflux collector with an additional pipe to provide a single reflux drain system to the underlying multi-threaded contact device, while for two adjacent contact devices the product of the total cross-section of the overflow pipes at a speed reflux flow in overflow pipes is equal to the sum of the product of the total cross-section of the transfer pipes by the speed outflow of phlegm in transfer pipes and the product of the cross section of the additional pipe by the reflux flow rate in the additional pipe, which takes into account the increase in phlegm flow between two adjacent contact devices due to the introduction of circulating irrigation, and the outlet connector for circulating irrigation communicated with the corresponding phlegm collector with an additional pipe to form the system phlegm flow to the underlying multi-threaded contact device taking into account the output of circulating irrigation, while for two adjacent of stroke devices, the product of the total cross section of the overflow pipes by the reflux flow rate in the overflow pipes is equal to the difference between the product of the total cross section of the transfer pipes and the reflux flow rate in the transfer pipes and the product of the cross section of the additional pipe and the reflux flow rate in the additional pipe, which takes into account the decrease in reflux flow between two adjacent contact devices due to the withdrawal of circulating irrigation.

It is also advisable that contact devices with a different number of flows on adjacent contact devices be made rotated 90 degrees, which makes it possible to constructively simplify the strapping of the upper adjacent contact devices with a phlegm collector using transfer pipes, as well as a phlegm collector with a phlegm distributor on the underlying contact device using overflow pipes, positioning the overflow and drain pipes in the same plane.

Mass transfer is formed in the fractionating apparatus under the condition of a cross current of the liquid and vapor (gas) phases, while using plate contact devices, the liquid phase moves horizontally along the plate web in several streams, and the vapor (gas) phase moves vertically and sparges into the liquid phase through valves, caps or other devices installed in the plate plate, and when using cross-precision nozzle contact devices in the form of packets of regular nozzles from the grid and and lathing liquid phase pellicular moves vertically package volume multiple streams according to the number of packets and the vapor (gas) phase moves horizontally, passing through a liquid phase film.

The figure 1 presents a diagram of a fragment of a fractionating apparatus with two and three-threaded adjacent contact devices in the context, in figures 2 and 3 shows the mutual spatial arrangement in the body (in figures 2 and 3 is not shown) of three and four-flow adjacent contact devices, shifted with rotation 90 degrees.

Figures 1 and 2 include the following sections and elements:

1 - housing;

2 - pocket;

3 - drain partition;

4 - transfer pipe;

5 - a collection of phlegm;

6 - section phlegmy drain phlegmy;

7 - drain partition;

8 - reflux collection section of the reflux collection;

9 - phlegm dispenser;

10 - overflow pipe;

11 - two-line plate;

12 - three-line plate;

13- four-potted plate.

The fractionating apparatus operates as follows.

In the upper part of the apparatus 1, double-flow trays 11 are sequentially installed, and three-stream trays 12 are sequentially installed in the lower part of the apparatus, due to the intensive condensation of the vapor phase and, consequently, an increase in the flow rate of the liquid phase, which requires further three-stream execution of the contact device. Moving and converting the liquid phase stream (reflux) from the last two-line plate 11 to the first three-line plate 12 is ensured by the fact that the phlegm of each stream of the two-line plate 11 is poured through the drain wall 3 and removed from the plate web by transfer pipes 4 to the reflux collector 5. In the drain section phlegm phlegmy collection 6 provides a mixture of all the phlegm flows flowing down from the overlying plate, providing averaging of the composition of the phlegm entering the underlying plate, since in separate reflux streams, constituents from the overlying trays, the reflux formulations are possible fluctuations due to inhomogeneity factors hydrodynamic mass transfer in separate threads threaded plates (fluctuations in flow rates, contact times, phases, etc.). The phlegm of the overlying multi-threaded (two-threaded) plate averaged over the drainage wall 7 flows into the phlegmy collection section of the phlegm collector 8, from where it is distributed using overflow pipes 10 according to the number of flows of the underlying multi-threaded (three-threaded) plate into the phlegm distributor 9, from where the phlegm enters the pocket 2 underlying plates.

Thus, the claimed invention allows to solve the problem of developing a highly efficient fractionating apparatus, when the load of contact devices in the liquid phase and / or vapor phase is high or sharply changes in the fractionating apparatus and it is necessary to use contact devices with a different number of flows in one apparatus.

Claims (14)

1. A fractionating apparatus, comprising a housing equipped with fittings for introducing raw materials, irrigation, vapors from a boiler or a hot stream from a furnace, withdrawing bottoms, top and side products, temperature, pressure, flow and quality measuring systems, manholes and mass transfer sections, in which are mounted contact device nozzle and / or plate cross-type with drain partitions, pockets and transfer pipes, characterized in that when multi-threaded design of contact devices with different number of flow For adjacent contact devices in the space between contact devices with multi-threaded (even and odd) versions of the contact devices, a phlegm collector is placed that communicates with the transfer pipes of the overlying contact device and communicates with overflow pipes with a reflux distributor to the underlying contact device, in this case in case of circulation irrigation during fractionating apparatus choke input and output of circulating irrigation are communicated with the corresponding collections of phlegm. 2. The fractionating apparatus according to claim 1, characterized in that the phlegm collector has a phlegm collection section and a phlegm drain section separated by a drain wall. 3. The fractionating apparatus according to claim 2, characterized in that the reflux section of the reflux collector is connected to the transfer pipes of the overlying contact device. 4. The fractionating apparatus according to claim 2, characterized in that the reflux collection section communicates with the reflux distributor to the underlying contact device using overflow pipes. 5. The fractionating apparatus according to claim 1, characterized in that the phlegm distributor is low-pressure. 6. The fractionating apparatus according to claim 1, characterized in that the phlegm distributor is made in the form of a comb collector. 7. The fractionating apparatus according to claim 1, characterized in that the reflux dispenser is made in the form of an annular collector. 8. The fractionating apparatus according to claim 1, characterized in that for two adjacent contact devices, the total cross-section of the overflow pipes is equal to the total cross-section of the transfer pipes, provided that the reflux rate at the two adjacent contact devices is constant. 9. The fractionating apparatus according to claim 1, characterized in that for two adjacent contact devices, the ratio of the product of the total cross section of the overflow pipe to the reflux flow rate in the overflow pipe to the product of the total cross section of the overflow pipe to the reflux flow rate in the overflow pipe is equal to the ratio of the reflux rate two adjacent contact devices. 10. The fractionating apparatus according to claim 1, characterized in that the nozzle of the input of the circulating irrigation communicates with the phlegm collector with an additional pipe. 11. The fractionating apparatus according to claim 10, characterized in that for two adjacent contact devices, the product of the total cross section of the overflow pipes by the reflux flow rate in the overflow pipes is equal to the sum of the product of the total cross section of the transfer pipes and the reflux flow rate in the transfer pipes and the product of the cross section additional pipe at the reflux flow rate in the additional pipe. 12. The fractionating apparatus according to claim 1, characterized in that the outlet fitting of the circulating irrigation communicates with the phlegm collector with an additional pipe. 13. The fractionating apparatus according to claim 12, characterized in that for two adjacent contact devices, the product of the total cross section of the overflow pipes by the reflux flow rate in the overflow pipes is equal to the difference between the product of the total cross section of the transfer pipes and the reflux flow rate in the transfer pipes and the cross section product additional pipe at the reflux flow rate in the additional pipe. 14. The fractionating apparatus according to claim 1, characterized in that the contact devices with a different number of flows on adjacent contact devices are made offset with a rotation of 90 degrees.

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