RU2729618C1 - Rectification plant device - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to equipment for rectification of alcohol. Invention relates to a rectifier apparatus comprising a sequentially connected interconnected distillation cube provided with a heater, reflux tank with a steam lift reflux for feed of a rectification column, a rectification column and a dephlegmator. Reflux tank includes housing equipped with branch pipe of connection with rectification column and connection pipe with distillation cube, reinforcing column of reflux tank in form of cylinder with contact heat and mass exchange means, installed inside housing and communicating with branch pipe of connection with distillation cube, cylindrical nozzle with holes along the perimeter of its lower part, enclosing the reinforcing column of the reflux tank, installed coaxially with it with a gap δ, located in range from 0.03 to 0.07 of reflux tank reinforcing column pipe wall radius, wherein the height of the cylindrical nozzle is greater than the height of the reinforcing column of the reflux tank. Reflux baffle is arranged above cylindrical nozzle opposite branch pipe of connection with rectification column. Housing is equipped with a nozzle with a tap for draining reflux residues, which are arranged in the lower part of the housing, and a nozzle in the upper part of the housing for installation of a thermometer.EFFECT: high degree of purification of alcohol from impurities, considerable reduction of sampling time and maximum possible yield of the commercial product.3 cl, 5 dwg

Description

The invention relates to equipment for the rectification of alcohol, namely to installations used for batch distillation with fractionation. In particular, to installations used for the secondary periodic distillation of crude alcohol obtained from brews prepared from sugar-containing and starch-containing raw materials, in order to obtain rectified alcohol in the process of such distillation at home.

The invention can be used both in the field of home distillation and in the food industry, in particular in the production of high quality grain and fruit distillates, with a certain qualitative and quantitative composition of impurities by the method of periodic distillation.

The process of distillation of alcohol-containing products, for example, raw alcohol, at home is usually built on the principle of operation of rectification columns [1], in which the heat and mass transfer process is carried out upon contact of vapor and liquid.

Almost the majority of rectification units for home use contain a distillation cube, a rectification column, a reflux condenser or a heat exchanger (refrigerator-condenser) connected in series. Such installations are disclosed, for example, in the RF patent RU2081661, IPC B01D 3/32, publ. 06/20/1997, RF patent for useful model RU141716U1, IPC B01D 3/00, publ. 10.06.2014, RF patent for utility model RU169872, IPC B01D 3/00, publ. 04.04.2017, RF patent RU2667286, IPC B01D 3/28, publ. 09/18/2018. In the rectification columns of the mentioned installations, low-boiling fractions - products with a lower condensation temperature - are concentrated in the upper part of the rectification column, and high-boiling products - with a higher condensation temperature - in the lower one. parts of the rectification column. During operation, the vapors rise to the top of the rectification column, cool, condense in a heat exchanger (reflux condenser or condenser) and flow back in the rectification column towards the upward-moving vapors of the starting material. Thus, in the upper part of the distillation column, vapors move from bottom to top in countercurrent flow and liquid flows from top to bottom. Flowing downward, the liquid is enriched with high-boiling components, and the higher the vapors rise upward in the distillation column, the more they are enriched with low-boiling components. Thus, the alcohol discharged from the upper tray of the distillation column is enriched in a low-boiling component, while part of the condensed alcohol is removed, and the other part, called reflux, returns back to the distillation column and, when draining, interacts with new alcohol-containing vapors rising up the column.

The disadvantages of the mentioned installations are:

- low degree of purification from intermediate and end fractions, K _{rect of} which changes during the operation of the device,

- the impossibility of maintaining a level sufficient for the normal operation of the reflux column, without reducing the selection of alcohol from the distillation column. As the alcohol content of the distillation still decreases, the absolute amount of alcohol evaporated from the distillation still decreases (per unit time), therefore, less and less alcohol can be taken from the distillation column without draining it and disrupting the heat and mass transfer process inside it. As a result, there is a forced decrease in the rate of alcohol selection.

Partially the above disadvantages can be eliminated by using a known technical solution, see the electronic resource URL: https://youtu.be/sapwww-yLbU, providing an increase in the period of the normal level of reflux of the distillation column, selected as a prototype.

The technical solution for the prototype is implemented in the form of a reflux accumulator, which is located between the distillation still and the rectification column. The main purpose of the reflux accumulator is the accumulation at the beginning of the operation of the rectification column of the return reflux flowing into it from the rectification column, followed by its boiling at the final stage of operation, and feeding the rectification column with highly alcoholic steam evaporated from the reflux accumulator to improve its operation at the final stage of rectification.

The diagram of the reflux accumulator as part of the rectification plant according to this technical solution is shown in Fig. 1, on which 1.1 is a rectification column, 2.1 is a reflux accumulator body, 3.1 is a distillation cube, 4.1 is a reinforcing column of a reflux accumulator, 5.1 is a filling of a reinforcing column of a reflux accumulator, 6.1 is a reflux collector (receiver-distributor).

The reflux accumulator creates the conditions for the operation of the rectification column 1.1 , installed on the body of the reflux accumulator 2.1 during some part of the rectification process, due to the power supply of the reinforcing column 4.1 of the reflux accumulator, which is fed by the return reflux from the rectification column, which begins to flow when accumulating to the level of the upper cut of the reinforcing column reflux accumulator. This allows you to maintain the rectification process and the selection of a commercial product up to the production of more than half of the crude alcohol in the distillation still 3.1 without reducing the reflux ratio (FP). The use of a strengthening column 4.1 of a reflux accumulator with a contact heat and mass transfer agent in the form of filler 5.1 increases the degree of purification from impurities of the bottoms vapor entering the distillation column 1.1 , refluxed with reflux accumulated in the reflux accumulator, and the selected commercial material. At the same time, this installation does not provide the maximum possible yield of the marketable product due to a significant reflux residue in the reflux accumulator, as well as an insufficient degree of purification of vapors from impurities at the final stage of rectification due to the interruption of the phlegm supply to the strengthening column of the reflux accumulator when the reflux residue in the reflux accumulator boils. ... At this moment (usually at the stage when the temperature of the cube reaches 92.0-92.5 ° C) the reflux accumulator begins to feed the column with highly alcoholic steam. However, at the same time, the strengthening column of the reflux accumulator is deprived of the phlegm supply (the level in the reflux accumulator falls below the overflow). This leads to the fact that low-alcohol vapors from the cube begin to fly without reinforcement to the exit from the reflux accumulator.

For some time, the boiling of the reflux residue in the reflux accumulator and the generation of highly alcoholic steam, which is mixed with the bottom vapors, compensates for the breakthrough of additional impurities from the still, reducing their relative concentration in the vapor feeding the distillation column. However, after a short time, as the alcohol boils off from the accumulated reflux in the reflux accumulator, the proportion of impurities in the resulting vapor increases, and the operator is forced to complete the process of selecting the marketable product. This usually occurs at a cube temperature of about 94.5-95.0 ° C.

The objective of the present invention is to eliminate the disadvantages of the prototype. This is achieved by the process of rectification of the alcohol-containing material, which ensures the efficient operation of the rectification plant without reducing the selection of alcohol from the rectification column, with the production of high-quality alcohol until the alcohol in the distillation still is completely exhausted - until the Tcube reaches 100 ° C.

The technical result of the invention is an increase in the degree of purification of alcohol from impurities, a significant reduction in the selection time and the maximum possible yield of a marketable product - rectified alcohol.

The specified technical result is achieved due to the constructive solution of the device of the rectification plant, containing in series connected to each other communicating distillation cube, equipped with a heater, a reflux accumulator with a steam-lift reflux lift for feeding the rectification column, a rectification column and a reflux condenser.

A reflux accumulator with a steam-lift reflux lift for feeding the distillation column includes:

a body equipped with a connection pipe for a rectification column and a connection pipe for a distillation still,

reinforcing column of the reflux accumulator, made in the form of a cylindrical body with contact heat and mass transfer means installed inside it, and communicating with the connection pipe with the distillation cube,

a cylindrical nozzle with holes along the perimeter of its lower part, covering the reinforcing column of the reflux accumulator, installed coaxially with it with a gap δ of the wall gap, while the height of the cylindrical nozzle is greater than the height of the cylindrical body of the reinforcing column of the reflux accumulator,

a reflux baffle located above the cylindrical packing opposite the connection pipe with the rectification column,

at the same time, the mentioned body is equipped with a fitting with a valve for draining the remaining reflux, located in the lower part of the body, and a fitting in the upper part of the body for installing a thermometer.

Other features of the invention will be apparent from the following description.

The invention is illustrated by drawings, in which the same elements, parts or assemblies are designated by the same reference numbers.

FIG. 1 is a schematic diagram of a prior art reflux accumulator.

FIG. 2 is a diagram of the device of a rectification plant using a reflux accumulator with steam-lift lift according to the present invention.

FIG. 3 is a schematic diagram of a reflux accumulator with a steam-lifting reflux lift for feeding the distillation column according to the present invention.

FIG. 4 and FIG. 5 - explain the processes during the operation of a phlegm accumulator with a steam-lift phlegm rise at the stages of body selection.

FIG. 2 shows a diagram of a rectification plant according to the invention. The distillation unit contains a series-connected communicating distillation cube 3 , equipped with a heater, a reflux accumulator 2 with a steam-lift reflux lift for feeding the distillation column, a distillation column 1 and a reflux condenser 4 . Docking and fixing of the branch pipes of the connected components of the installation is carried out using detachable connections, for example, a clamp connection, as in the embodiment below. The dephlegmator 4 is equipped with a tubular alcohol outlet 5 . The distillation column 1 can be of any known type, determined by the type of used mass and heat exchange contact means, for example, disc or packed.

FIG. 3 shows a schematic diagram of a reflux accumulator with a steam-lift reflux lift for feeding the rectification column according to the invention. The reflux accumulator consists of a housing 10 , which has a branch pipe 8 of connection with a distillation column 1 , a branch pipe 9 of a connection with a distillation still 3 , a reinforcing column 11 of a reflux accumulator in the form of a cylindrical body with contact heat and mass transfer nozzles inside it, communicating through a branch pipe 9 with

distillation cube 3, a cylindrical nozzle 12 , covering the reinforcing column 11 of the reflux accumulator and a reflux baffle 13 , located above the cylindrical nozzle 12 opposite the branch pipe 8 connecting the body 10 of the reflux accumulator with the rectification column 1 . The body 10 of the reflux accumulator is equipped with a fitting 7 with a valve for draining the remaining reflux (luther), located in the lower part of the body 10 , and a fitting 6 in the upper part of the body, on the vapor zone of the reflux accumulator, for installing a thermometer. To ensure the steam-lift rise of phlegm in the lower part (bottom) of the body 1 , a cylindrical nozzle 12 is installed coaxially with respect to the reinforcing column 11 of the reflux accumulator with a gap δ of the wall gap between them. The cylindrical nozzle 12 is made with a height greater than the height of the cylindrical body of the reinforcing column of the reflux accumulator. At the lower end section of the cylindrical packing, openings 14 are made in the form of holes through which reflux is supplied to the gap δ of the wall gap during the operation of the rectification unit. As heat and mass transfer means of the strengthening column, bubble cap trays 15 or spiral-prismatic packing or other suitable fillers can be used.

Operation of a rectification plant with a reflux accumulator according to the invention.

1st stage. Filling reflux into a phlegm accumulator with a steam-lift raising the reflux to feed the rectification column.

Bottom liquid, poured into the distillation still 3 , is heated by a heater (not shown) of the distillation still. After the bottoms liquid boils, the resulting vapor passes through the reflux tank 2 into the distillation column 1 and reaches the reflux condenser, in which it condenses. All condensed reflux flows back into the distillation column and meets with steam, the distillation column starts to work. Further, the reflux, flowing down through the distillation column, meets the reflux baffle 13 and flows from it into the reflux accumulator 2 and excluding the reflux directly into the distillation still 3 . At this time, there is no product selection from the system, work is underway for oneself - concentration of the head fractions in the upper part of the distillation column 1 . The distillation column is fed with steam as before, and the reflux reflux fills the internal space of the reflux accumulator housing 10 for some time. The strengthening column 11 of the reflux accumulator at this moment does not work without reflux. A thermometer installed in the nozzle 6 of the reflux accumulator shows a steam temperature that is practically equal to the vat boiling point.

2nd stage. Increasing the alcohol content of the phlegm storage.

When the reflux level reaches the upper cut of the cylindrical body of the reinforcing column 11 of the reflux accumulator, reflux is overflowed into the reinforcing column of the reflux accumulator, and its bubbling on contact heat and mass transfer devices 15 , for example, plates or spiral-prismatic packing. The return of reflux continues to the reflux accumulator, but the distillation column begins to feed on steam, not from the distillation still, but from the strengthening column of the reflux accumulator, and the steam sharply becomes more alcoholic. The reflux accumulator thermometer shows a fairly rapid drop in temperature. At this point, head selection begins. The reflux flowing down from the distillation column to the reflux accumulator also increases its alcoholicity, and, as the reflux in the reflux accumulator is replaced by a more alcoholic one, a further gradual decrease in the temperature of the steam feeding the rectification column to the working temperature occurs.

The number of trays 15 (or the height of the layer of the spiral-prismatic packing) in the reinforcing column 11 is selected in such a way that the alcohol content of the accumulated reflux in the reflux accumulator gives steam to feed the distillation column 1 with a temperature of about 79 ° C. Accordingly, the strength of the reflux in the reflux accumulator will be about 90%. Such a high alcohol content, as is known, guarantees the minimum content of the lower intermediate, end and tail impurities in the alcohol vapor feeding the distillation column.

3rd stage. The operation of the reflux accumulator with a steam-lift reflux lift for feeding the rectification column in the first phase of the body selection (Fig. 4).

At the beginning of the selection of the body, the operator sets this or that FF, which he usually set when working without a reflux accumulator, for example, FF = 4. In this case, the return reflux from the distillation column 1 is still sufficient to feed the reinforcing column 11 of the reflux accumulator, and the process in in general, it does not differ at all from that which was carried out before the installation of the reflux accumulator, except for the moment that the overall separation of the system has increased (several reinforcing plates of the reinforcing column of the reflux accumulator have been added to the system). The temperature of the steam in the reflux accumulator is perfectly stable and does not change until the temperature of the bottom steam flowing into the bottom of the strengthening column of the reflux accumulator becomes approximately 90-91 ° C.

4th stage. The operation of the reflux accumulator with a steam-lift reflux lift for feeding the rectification column, in the second phase of the body selection (Fig. 5)

When the above-described conditions are reached, a temperature gradient appears in the lower part of the wall of the cylindrical body of the reinforcing column 11 of the reflux accumulator, which is sufficient to boil the reflux located in the gap δ of the paneled gap between the body of the reinforcing column 11 of the reflux accumulator and the cylindrical packing 12 , covering the reinforcing column of the reflux accumulator with the said gap δ. As a result of this, a vapor-lift rise occurs: the vapor (alcohol) arising in the wall gap rushes upward, and at the same time carries along a certain amount of phlegm in a liquid state. Since the height of the cylindrical packing is greater than the height of the body of the reinforcing column of the drive, the following processes begin to take place:

- additionally formed in the lower part of the wall gap of the reflux accumulator, a highly alcoholic alcohol vapor feeds the rectification column together with the vapor generated on the upper plate of the strengthening column of the reflux accumulator;

- liquid phlegm, carried out by the steam lift to the overflow level (cut of the cylindrical body of the reinforcing column of the reflux accumulator), enters the reinforcing column of the reflux accumulator and feeds it, maintaining the optimal performance of the reinforcing column of the reflux accumulator .

At the same time, the level of reflux in the reflux accumulator begins to decrease, and the communicating vessels (the main volume of the reflux accumulator and the volume in the wall space) become non-equilibrium (in the reflux accumulator it is lower and lower, and in the wall space - to the level of overflow into the strengthening column of the reflux accumulator) - at the same time, a constant and continuous steam-lift rise of phlegm continues in the wall gap from the main volume of the reflux accumulator through hole 14 , and the strengthening column of the reflux accumulator receives full-fledged irrigation from the wall gap.

Thus, the consumption of the reflux stored in the storage tank allows not to reduce the amount of alcohol withdrawal from the distillation column (not to change the PP) with more and more decreasing alcoholic content in the distillation still, and feeding the strengthening column of the reflux storage tank with the stored reflux eliminates the breakthrough of the bottom steam into the distillation column.

A stable steam-lift lift is achieved by choosing the size of the gap δ of the wall gap between the reinforcing column 11 of the reflux accumulator and the cylindrical nozzle 12 , as well as the number and shape of the holes 14 in the lower part of the cylindrical nozzle intended for the reflux flow from the main volume (accumulation zone) into the wall gap - the zone boiling - between the reinforcing column 11 of the reflux accumulator and the cylindrical packing 12 . These parameters are determined experimentally for a specific distillation column and a distillation still so that by the time the extremely low residual volume of the reflux stored in the storage tank is reached, the distillation still has been practically exhausted, and the alcohol content of the distillation residue was close to zero (the boiling point of the still is 100 ° C at normal conditions). To ensure a stable steam-lift rise of phlegm for irrigation of the reinforcing column, the size of the gap δ of the wall gap is selected in the range of 0.03-0.07 from the radius of the wall of the cylindrical body of the reinforcing column 11 .

5th stage. Completion of work.

With a correctly selected volume of the reflux accumulator, the steam temperature in the second half of the work begins to rise very slowly - this is due to the replacement of the high-virtuosic reflux accumulated in the reflux accumulator at the initial stage of work by a lower-virtuoso one that flows down from the rectification column at the last stage of the body selection process. At the same time, when the limiting temperature in the reflux accumulator is reached, it is usually + 2- + 3 ° C higher than the starting temperature (at the beginning of the selection of the body) in the reflux accumulator, approximately 12-15% of the maximum volume of the stored reflux remains, and in the distillation still the strength of the vat residue at the same time it is less than 1% alcoholic.

In practice, the specific figures are as follows. With the volume of the still bulk of 40 liters with a strength of 40% and a volume of the reflux accumulator of 2 liters, at the end of the process, a still remains of 28 liters with a strength of 0.7%, and in the buffer 0.3 liters with a strength of 84%.

It is also possible, if the limiting temperature has already been reached, and the distillation cube has not yet been completely drained of alcohol, a one-time increase in PS (decrease in selection by half). In this case, the return of reflux to the distillation column will increase, the discharge of reflux from the distillation column to the reflux accumulator will increase, and the temperature rise in the reflux accumulator will stop, which will make it possible to continue working, albeit somewhat more slowly, but at the same time completely exhaust the alcoholicity of the bottoms residue.

Thus, the technical solution for a reflux accumulator with a vapor-lift reflux lift for feeding the distillation column, using a reinforcing column of a reflux accumulator and a cylindrical packing covering it with a gap δ between them (wall gap), provided, under the conditions of temperature conditions of the rectification process, obtaining a vapor-lift rise , and constant feeding of the strengthening column of the reflux accumulator during the entire period of rectification. In turn, the provision of constant power supply to the strengthening column of the reflux accumulator results in a simultaneous improvement in all performance indicators of the rectification plant according to the present invention:

- improving the quality of alcohol by feeding the distillation column with highly alcoholic steam with a low content of impurities, which accumulate mainly in the strengthening column of the reflux accumulator and remain in the distillation still;

- acceleration of the process of alcohol rectification (saving time), due to the practically unchanged PP throughout the alcohol rectification;

- an increase in the yield of a marketable product for rectification, by completely depleting the distillation residue and a small final residue in the reflux accumulator, as a result of pumping out the accumulated reflux from the zone of the main volume of the reflux accumulator using a steam-lift reflux lift.

Cited sources

1. Alexandrov I.A. Rectification and absorption apparatuses. 2nd ed. revised - Moscow: Chemistry, 1971. - 296 p.

Claims (8)

1. The device of the rectification plant, containing in series connected to each other communicating distillation cube, equipped with a heater, a reflux accumulator with a steam-lift reflux lift for feeding the rectification column, a rectification column and a reflux condenser, in which the reflux accumulator includes, a body equipped with a connection pipe for a rectification column and a connection pipe for a distillation still, a strengthening column of a reflux accumulator in the form of a cylinder with contact heat and mass transfer means, installed inside the body and communicating with the connection pipe with the distillation cube, cylindrical packing with holes along the perimeter of its lower part, covering the reinforcing column of the reflux accumulator, installed coaxially with it with a gap δ ranging from 0.03 to 0.07 from the radius of the pipe wall of the reinforcing column of the reflux accumulator, while the height of the cylindrical packing is greater the height of the reinforcing column of the reflux accumulator, a reflux baffle located above the cylindrical packing opposite the connection pipe with the rectification column, the said body is equipped with a fitting with a valve for draining the remaining reflux, located in the lower part of the body, and a fitting in the upper part of the body for installing a thermometer. 2. A device according to claim 1, wherein said contact heat and mass transfer means of the rectification column are made in the form of trays or spiral-prismatic packing. 3. A device according to claim 1, in which heat and mass transfer means in the form of plates are used in the strengthening column of the reflux accumulator.

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