In the distillation column, the fractions are separated. Design and operation of distillation columns
Rectification is a method of separating the components of a mixture, based on the property of the components of a given mixture to boil away at different temperatures.
Rectification is the process of separating binary, multicomponent or continuous mixtures into practically pure components or their mixtures (fractions), differing in boiling points (for binary and multicomponent mixtures) or boiling intervals (for continuous mixtures).
Analysis of petroleum products for the content of individual hydrocarbons and their classes shows that oil and its fractions are a complex multicomponent mixture. The number of components in oil exceeds 2000. Due to the large number of components, oil is considered to be a continuous mixture and its composition is expressed by a curve of true boiling points (TBC), which has a smooth, continuous nature.
Therefore, the rectification process is a mass transfer that occurs in both directions between two phases of the mixture, one of which is liquid and the other is vapor. In other words, this is a repeatedly repeated contact interaction of nonequilibrium phases in the form of liquid oil and steam.
The rectification process is carried out as a result of contact between steam and liquid flows. In this case, an indispensable condition is the movement of steam and liquid towards each other along the height (length) of the distillation apparatus. The driving force for heat and mass transfer between steam and liquid in the apparatus is the temperature difference along the height (length) of the apparatus.
Types of distillation plates
The distillation column is one of the central apparatuses of a technological installation for the primary processing of oil or petroleum products. The use of this device is caused by the need to implement simple way separation of oil or its products into fractions depending on their boiling points. This method is called rectification, and the apparatus for carrying out this process is called a distillation column.
But alone distillation column cannot cope with the tasks of separating factions. At oil refineries, the column is closely connected with a variety of other equipment - pumping, heat exchange, furnace, separation.
It is most convenient to illustrate the principle of operation of a distillation apparatus using the example of a column with cap-shaped plates.
Distillation columns
Heat and mass transfer between countercurrently moving nonequilibrium vapor and liquid phases in rectification rooms is carried out on contact devices (CD), which are often called “plates”.
In distillation columns, the steam irrigation flow is created by heating elements (furnace, input of superheated water steam), and the liquid flow is created by condensation devices (cold circulation irrigation).
As a result of the interaction between the vapor and liquid phases at the HRSG, in accordance with the laws of thermodynamic vapor-liquid equilibrium, the vapor phase is enriched in low-boiling components, and the liquid phase is enriched in high-boiling components. Therefore, it is the KU that largely determines the overall efficiency of the separation process.
For oil columns in general and for AVT columns in particular, a number of characteristic features can be identified:
- very high productivity of raw materials (up to 1000 m 3 / h for an atmospheric column);
- Heat is supplied to the separation system by fire heating of the raw material in a tubular furnace (main and vacuum columns AVT), injection of superheated water vapor (almost all columns) and circulation of a “hot jet” (topping column AT);
- the latter circumstance involves the use of special separation zones to separate the vapor and liquid phases;
- The rectification scheme contains remote stripping sections, as well as circulating irrigation, which suggests the possibility of organizing side withdrawals of the liquid phase and supplies of both steam and liquid phases at the HRSG at several points along the height of the column.
By the way, read this article too: Vacuum column
These features must be taken into account when choosing the designs of contact devices in the design of oil separation units.
Operating principle of a distillation column
The design of a distillation column is a vertical cylindrical container of varying or constant cross-section, which is used to physically separate a mixture of hydrocarbons and obtain the required petroleum products of a given quality as a result of rectification.
In the column, vapors move upward from plate to plate due to the pressure difference in the evaporation space and at the top of the column. The liquid flows down the trays and drainers under the influence of gravity.
The distillation column can be divided into 3 functional parts:
- Concentration section – located above the point where raw materials enter the apparatus
- Feed section - in the center of the column, raw materials are supplied to the food plate
- Stripping section – located below the raw material input point
Column feed section 
Concentration section 
Stripping section For the rectification process to take place, the oil temperature must be lower than the temperature of the supplied steam. This consequence comes from the properties of the equilibrium system. If the oil temperature was equal to or lower than the steam temperature, the rectification process would be impossible.
The rectification process can only be carried out for mixtures with different boiling points to allow the diffusion separation process to occur. To do this, the liquid moves from top to bottom, and the vapor moves from bottom to top to ensure the best contact and interaction of the phases.
Classification of distillation columns
Column devices can be divided depending on the technological process:
- Atmospheric and vacuum distillation (oil and fuel oil);
- Secondary distillation of gasoline;
- Stabilization of oil, gas condensates, unstable gasolines;
- Fractionation of refinery, petroleum and natural gases;
- Distillation of solvents during oil purification processes;
- Separation of products of thermodestructive and catalytic processes of processing of petroleum raw materials and gases, etc.;
By the way, read this article too: Cross flow nozzles (CFL)
Types of contact devices for distillation columns
To carry out the rectification process in column devices Be sure to use contact devices:
- Attachments;
- Disc-shaped;
- Rotary.
Rotary columns are not widely used, while plate and packed columns are very popular.
Plate with cap contact devices Video: design and operation of a distillation column
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Today, people are much more relaxed about getting intoxicating drinks at home than they were a couple of decades ago. We don’t see anything wrong with this, and let’s be honest: many of us have a well-founded interest in the peculiarities of such a mysterious process. That is why we decided to initiate our readers into the “sacrament”, having learned which, you can guarantee yourself the quality of the product, which retail chain buyers will never have confidence in.
viktor50 User FORUMHOUSE
One poisoning with a surrogate, which you can run into in any supermarket, and treatment can cost much more money than making an alcohol column.
Distillation and rectification: the essence of the processes and the differences between them
Distillation (distillatio) - translated from Latin - flowing drop by drop. The physical essence of the process is the evaporation of liquids and the subsequent condensation of the resulting vapor (most modern people understand distillation as banal distillation, and they are right).
Rectification (rectificatio) – translated from Latin – correction. The essence of the process is the separation of multicomponent liquid mixtures into components. Such sorting is possible due to the different boiling temperatures of different components (light fractions boil at a lower temperature, and heavy fractions at a higher temperature).
It is possible to isolate a product suitable for consumption from a “ripe” mash through simple distillation. But the resulting substance, which is raw alcohol (moonshine), will contain a huge amount of foreign impurities that do not have the best effect on the taste of the drink.
Glevakhovod User FORUMHOUSE
If you simply condense the vapors in the refrigerator (in a cooled coil) using the old-fashioned method, you will get a condensate (distillate) of everything that was in the vapor - moonshine (cloudy and with an unpleasant odor).
Therefore, some sooner or later come to the need to use more advanced methods for producing alcohol-containing products from homemade raw materials. We are talking about rectification.
Petrovich69 User FORUMHOUSE
We all went through stages of experience and understanding: first you take a distiller (universal and with reinforcement), then you buy additional reinforcement drawers or a plate column, and only then you begin to receive a quality product. Otherwise it’s pure self-indulgence, a waste of time and money, not to mention your health.
The creation of a distillation column will pay off - you won’t have to worry about the presence of toxic compounds in the final product.
Carcinogenic impurities are divided into two types:
- Light compounds - ethers, acetone, higher alcohols, etc. Light compounds are also called “heads” - perhaps because they have a low boiling point (from 65 ° C) and leave the distillation tank first.
- Heavy - water, fusel oils, etc. Heavy compounds are called “tails”. They are the last to leave the boiling substance (at a higher temperature - from 85°C). At the same time, it is also undesirable to use “tails” due to the high content of toxic impurities, but they can be used in the process of subsequent distillation.
“Body” is the product for which the rectification process actually begins. We are talking about ethyl alcohol.
The boiling point of ethyl alcohol at atmospheric pressure is 760 mm Hg. Art. is 78.39°C. This indicator directly depends on the percentage of ethanol in the solution. It can also decrease or increase in proportion to changes in atmospheric pressure.
If you learn to correctly configure the operating parameters of the rectifier, then you will always have the opportunity to obtain the most purified alcohol solution at the output, the strength of which is close to 96%.
Brief dictionary
Before continuing to study the topic, let's look at its basic concepts.
- An alcohol column (AC) is a device that allows you to produce ethyl alcohol with a high degree of purification at home. There are two types of alcohol columns: mash columns (BC) and distillation columns (RK). Their fundamental difference lies in the quality of the feedstock intended for distillation. Thus, a mash column, which is also called a “film” column, is intended for direct distillation of mash. Its design does not contain a special filler (nozzle), and it has limited separating ability, which does not allow obtaining a high-quality product. A distillation column (RC), which is also called “packed”, has a more advanced design. Thanks to a special filler (for example, stainless steel scourers for washing dishes), this device allows you to separate the existing fractions from each other with high precision. Raw alcohol (ordinary moonshine) obtained by distillation is used as a raw material for the distillation column. As practice shows, only a packed column allows obtaining a product with the maximum degree of purification. Therefore, when creating a device for producing ethanol at home, it is necessary to focus on the design of the distillation (and not the mash) column.
- Reflux (condensate) is a product that accompanies the rectification process and has a higher boiling point compared to the fraction separated at the current time. For example, the “body” in relation to the “heads” can be considered phlegm. The “tails” (in relation to the “body”) are also phlegm.
- A distillation cube is a rectifier container that contains raw alcohol to be distilled.
- The drawer is the working part of the distillation column, in which the initial solution is divided into its component fractions.
- Under-rectified is a highly purified product obtained by distilling the feedstock through an alcohol column.
The word “under-rectification” may not inspire confidence, but in fact, obtaining under-rectification is our ultimate goal.
Listo User FORUMHOUSE
From two pastures we make rectified moonshine - we install the lower tube, after which we long and patiently obtain alcohol (under-rectified, more precisely). Its strength is 96°, and its smell (for sugar mash) – quite normal. We don’t clean anything, the product turns out quite decent. After it you don’t even want to drink industrial vodka (in the morning it’s like a cucumber).
The strength of the under-rectified product often does not reach 96%, and it may contain odors of the original raw materials. However, the product is highly purified and of appropriate quality.
Why is RK better than a distiller?
The advantages of a distillation column are based on the design features of this device. RK allows you to consistently and with a high degree of efficiency separate the “heads” from the “body”, and the “body” from the “tails”. The principle of its operation is based on the physical effect of heat and mass transfer, which consists in the continuous mixing of rising vapors and downward reflux.
The process of heat and mass transfer occurs in a special element of the RK, which is called a rectifier pipe. Hot steam removes from the reflux those fractions that have a lower boiling point (as a rule, these are alcohols and other easily evaporated compounds). In this case, the phlegm flowing down takes away from the steam everything that has a higher boiling point (water, fusel oils, etc.).
In order for the process to proceed more intensively, the rectification chamber is filled with a special nozzle (filler), which increases the contact area of different fractions. As a result, at any given time, only the lightest chemical compounds enter the distillate selection unit.
Glevakhovod User FORUMHOUSE
If the selection is carried out slowly enough, then at first the distillate will contain the lowest boiling fractions: ethers, acetones, higher alcohols. These are "heads" and should not be drunk. But they go into glass washer. Then comes the alcohol - the “heart” of the product. Then there will appear: fusel, water and other heavy-boiling fractions (“tails”). They contain a large proportion of alcohol. They are collected and added to the mash during the next distillation to squeeze out the remaining alcohol.
It is impossible to obtain pure alcohol using a strengthening column. The heart, one way or another, will contain impurities. It will not be alcohol, but strong and purified moonshine. The better the column, the stronger and purer the moonshine.
As for a conventional distiller: with its help it is almost impossible to achieve a clear separation of fractions. But this device can be used to produce raw alcohol, from which a high-quality and purified product can subsequently be obtained (by distillation through a packed column). This will be much more practical, and many users of our portal have long mastered this method of obtaining a non-rectification certificate.
Glevakhovod
The purpose of my column on a pressure cooker is somewhat different than distilling mash (not on the same scale). It is needed to strengthen the distillate when distilling gin and sambuca.
Direct distillation of mash using a refrigerant is, of course, possible. But this process will be slow, troublesome and constantly threatening to clog the nozzle with boiling mash. In addition, in the case of direct distillation, there is a danger of obtaining an under-rectified product, which will be “enriched” in aldehydes beyond the norm. That is why, to obtain a high-quality product, it is preferable to resort to double distillation, using a distiller for the first distillation.
It was a theory. We will talk about the design and features of working with this device in the second part of this article, the content of which is based on the recommendations of our users - stay tuned to the portal!
If you would like to get acquainted with the experience of FORUMHOUSE users who have managed to achieve success in creating all kinds of products, you need to visit the corresponding section of our portal. Also take a look at the section - soon they will come in handy for a festive feast, as well as the preparations that our video will tell you about.
§ 13.2 Distillation columns: their design and operation
As mentioned above, rectification is carried out in special devices - rectification columns, which are the main elements of rectification plants.
Rectification process can be carried out periodically and continuously, regardless of the type and design of distillation columns. Let's consider the process of continuous rectification, which is used to separate liquid mixtures in industry.
Distillation column- vertical cylindrical apparatus with welded (or prefabricated) housing in which mass and heat exchange devices (horizontal plates) are located 2 or nozzle). At the bottom of the column (Fig. 13.3) there is a cube 3, in which the bottom liquid boils. Heating in the cube is carried out due to dead steam located in a coil or in a shell-and-tube heater-boiler. An integral part of the distillation column is the reflux condenser 7, designed to condense the steam leaving the column.
The rectification plate column works as follows. The cube is constantly heated, and the still liquid boils. The steam generated in the cube rises up the column. The initial mixture to be separated is preheated to boiling. It is served on a nutrient plate 5, which divides the column into two parts: lower (exhaustive) 4 and upper (strengthening) 6. The initial mixture from the nutrient plate flows onto the underlying plates, interacting on its way with steam moving from bottom to top. As a result of this interaction, the steam is enriched in the highly volatile component, and the liquid flowing down, depleted in this component, is enriched in the highly volatile one. At the bottom of the column, the process of extracting (exhausting) the highly volatile component from the initial mixture and turning it into steam takes place. Some part of the finished product (rectified product) is supplied to irrigate the upper part of the column.
The liquid entering the top of the column to irrigate and flowing through the column from top to bottom is called reflux. Steam, interacting with reflux on all plates of the upper part of the column, is enriched (strengthened) with a highly volatile component. The steam leaving the column is sent to the reflux condenser 7, in which it is condensed. The resulting distillate is divided into two streams: one as a product is sent for further cooling and to the finished product warehouse, the other is sent back to the column as reflux.
The most important element of a plate distillation column is the plate, since it is on it that the interaction of steam with liquid occurs. In Fig. 13.4 shows a diagram of the device and operation cap plate. She has a bottom 1, hermetically connected to the column body 4, steam pipes 2 and drain pipes 5. Steam pipes are designed to pass vapors rising from the bottom plate. Through the drain pipes, liquid flows from the overlying plate to the underlying one. A cap is mounted on each steam pipe 3, by which vapors are directed into a liquid, bubbled through it, cooled and partially condensed. The bottom of each plate is heated by the vapors from the underlying plate. In addition, when steam partially condenses, heat is released. Due to this heat, the liquid on each plate boils, forming its own vapors, which mix with the vapors coming from the underlying plate. The liquid level on the plate is maintained using drain pipes.
Rice. 13.3. Diagram of the distillation column: / - body; 2 - dishes; 3 - cube; 4, 6 - exhaustive and strengthening parts of the column; 5 -nutritional plate; 7 - reflux condenser
The processes occurring on the plate can be described as follows (see Fig. 13.4). Let vapors of composition A flow onto the plate from the bottom plate, and liquid of composition flows from the top plate through the overflow tube IN. As a result of the interaction of steam A with liquid IN(steam, bubbling through the liquid, will partially evaporate it, and will partially condense) a new vapor of the composition will be formed WITH and new fluid composition D, are in balance. As a result of the operation of the plate, new steam WITH richer in volatile substances compared to the steam coming from the lower plate A, that is, there is steam on the plate WITH enriched with a highly volatile substance. New liquid D, on the contrary, it became poorer in volatile matter compared to the liquid coming from the upper plate IN, that is, on the plate the liquid is depleted in the highly volatile component and enriched in the highly volatile component. In short, the work of the plate comes down to enriching the steam and depleting the liquid of the volatile component.
Rice. 13.4. Diagram of the design and operation of a cap plate: / - bottom of the plate; 2 - steam pipe;
3 - cap; 4 - column body; 5 - drain pipe
Rice. 13.5. Representation of the operation of the distillation plate on the diagram at-x: 1- equilibrium curve;
2 - line of working concentrations
A plate on which a state of equilibrium is achieved between the vapors rising from it and the liquid flowing down is called theoretical. In real conditions, due to the short-term interaction of steam with liquid on the plates, a state of equilibrium is not achieved. The separation of the mixture on a real plate is less intense than on a theoretical one. Therefore, to perform: the work of one theoretical plate, more than one real plate is required.
In Fig. Figure 13.5 shows the operation of a distillation plate using a diagram at-X. The theoretical plate corresponds to a shaded right-angled triangle, the legs of which are the increment in the concentration of the volatile component in the vapor, equal to mustache-y A , and the magnitude of the decrease in the concentration of the volatile component in the liquid is equal to x B - x D . The segments corresponding to the indicated changes in concentrations converge on the equilibrium curve. This assumes that the phases leaving the plate are in a state of equilibrium. However, in reality, the equilibrium state is not achieved, and the segments of concentration changes do not reach the equilibrium curve. That is, the working (real) plate will correspond to a smaller triangle than the one shown
in Fig. 13.5.
The designs of the trays of distillation columns are very diverse. Let's briefly consider the main ones.
Columns with cap plates widely used in industry. The use of caps ensures good contact between steam and liquid, effective mixing on the plate and intensive mass transfer between phases. The shape of the caps can be round, multi-faceted and rectangular, the plates can be single- or multi-cap.
A plate with grooved caps is shown in Fig. 13.6. Steam from the bottom tray passes through the gaps and enters the upper (inverted) gutters, which direct it to the lower gutters filled with liquid. Here, steam bubbles through the liquid, which ensures intense mass transfer. The liquid level on the plate is maintained by an overflow device.
Columns with sieve plates are shown in Fig. 13.7. The plates have a large number of small diameter holes (from 0.8 to 3 mm). The pressure of the steam and the speed of its passage through the holes must be in accordance with the pressure of the liquid on the plate: the steam must overcome the pressure of the liquid and prevent it from leaking through the holes onto the underlying plate. Therefore, sieve trays require appropriate regulation and are very sensitive to changes in the regime. If the vapor pressure decreases, the liquid from the sieve trays goes down. Sieve trays are sensitive to contaminants (precipitates), which can clog the holes, creating conditions for the formation of high pressures. All this limits their use.
Packed Columns(Fig. 13.8) differ in that the role of plates in them is played by the so-called “nozzle”. As a nozzle, special ceramic rings (Raschig rings), balls, short tubes, cubes, saddle-shaped, spiral-shaped, etc. bodies made of various materials (porcelain, glass, metal, plastic, etc.) are used.
Steam enters the lower part of the column from a remote boiler and moves up the column towards the flowing liquid. Distributed over a large surface formed by packed bodies, the steam comes into intense contact with the liquid, exchanging components. The nozzle must have a large surface per unit volume, exhibit low hydraulic resistance, be resistant to the chemical effects of liquid and steam, have high mechanical strength, and have a low cost.
Packed columns have low hydraulic resistance and are easy to use: they can be easily emptied, washed, purged, and cleaned.
Rice. 13.6. Plate with grooved caps: A- general form; b- lengthwise cut; V- diagram of the plate operation
Rice. 13.7. Diagram of the sieve plate structure: / - column body; 2 - plate; 3 - a drain pipe; 4 - hydraulic shutter; 5 - holes
Rice. 13.8. Scheme of a packed distillation column: 1 - frame; 2 - input of the initial mixture; 3 - steam; 4 - irrigation; 5 - lattice; 6 - nozzle; 7-outlet of high-boiling product j-. 8 - remote boiler
We will devote this article to obtaining pure alcohol from mash at home. What is possible if you only have a distillation column created according to all the rules in industrial conditions.
Let's look at many nuances that will be useful to the home distiller, tell you how to work with this equipment and what manufacturers are silent about when offering us their columns.
Moonshine brewing originated before our era. At first it was associated exclusively with distillation.
Reference. Distillation is any process involving the evaporation of a liquid, the purpose of which is to separate it into its components. For example, aromatic oils have been obtained by distillation since ancient times.
The first distillation apparatuses were created by alchemists-perfumers. History attributes the creation of copper alambiks and alkitars to the Persians. But long before them (in the Egyptian pyramids) devices were found that were clearly intended for distillation.
In the 16th century, many works and “improvement proposals” appeared regarding the improvement of distillation apparatus. The first prototypes of continuous columns appear. To ensure continuous operation, we experimented with sand, wax, and water baths. But the columns themselves were still air-cooled at that time. It was only towards the end of the century that it was discovered that water cooling was much more efficient.
Over the course of a century, distillation apparatuses were further improved, and by the beginning of the 18th century, a theory had matured about the possibility of rectification - the repeated return of evaporated liquid to the still and re-evaporation for purification and strengthening.
The result became evident by 1813, when the French inventors Bérard, Adam and Perrier received a patent for a continuous distillation column. Interestingly, the design of the industrial rectifier has not changed for more than two centuries. And today alcohol is produced using similar devices. Except that electronics have been added.
Moonshiners have long dreamed of getting pure alcohol at home. And they conducted more than one experiment in this direction. It turned out that it was impossible to simply take an industrial distillation column that works with tons of raw materials and reduce it to small sizes.
It will not provide the same productivity or product quality. The path to modern household rectifiers ended with the creation of a distillation column for home use, with the help of which it is possible to obtain an almost pure strength of 96°.
Concept of rectification
Rectification in chemistry is a process in which, due to heat and mass transfer, liquids consisting of two or more substances are separated into separate components. Separation occurs due to different mass and boiling point during repeated evaporation and return to the container.
In industry, rectification is used for distilling oil (dividing it into gasoline, diesel fuel, kerosene), and obtaining clean air components (oxygen, nitrogen, etc.). And, what interests us most is alcohol.
How does the process work?
Alcohol vapors, breaking off from the surface of the heated alcohol-containing liquid, rush upward along the column. Already on the way to the primary refrigerator-reflux condenser, they are partially cooled and heavy impurities, and with them water, return back to the distillation cube.
Lighter fractions follow higher, to a reflux condenser equipped with disc elements, on which the reflux comes into contact with the evaporated substances and the final separation of the liquids occurs.
To produce alcohol without impurities and ensure safety, the pressure at the top of the column is the same as in the atmosphere, so the rectifier must be equipped with a special tube so that there is no pressure drop.
Important. If the pressure decreases, the vapor density decreases as the evaporation rate increases. The column is choking. And an explosion is possible.
If the pressure increases too much, the separation of the mixture into fractions stops and the evaporation rate decreases.
Difference from distillation
A household dispenser cannot be considered a complete replacement for a distiller. This is rather a higher-quality unit for re-distillation, which makes it possible to process the primary raw alcohol of the first distillation in a straight-through distiller into a full-fledged one, devoid of fusel, but also the specific smell and taste inherent in the so-called aromatic moonshine.
And a little about concepts:
- At home we get under-rectification– alcohol with a strength of up to 96°. But you shouldn’t be afraid of this definition. This only means that the real rectified alcohol has a strength of 96.67°. And the degree of purification of the under-rectified product is significantly higher than the distillate.
- Fractional distillation (distillation) involves separation of condensate into fractions, according to the boiling point. The first components are light, low-boiling. Moonshiner's dictionary defines them as heads. The second is the body, their boiling point is close to ethyl alcohol - 78.4°C. The body is the most voluminous, drinkable part. Tails, the last fractions, enriched with high-boiling substances (fusel oils). When working with a distillation column, separation into fractions is also carried out, but according to a different principle.
- Reflux and its number. The quality of alcohol selection and the return of unnecessary impurities to the still depends on good irrigation of the condensate with phlegm, which irrigates the condensate entering the plates (nozzles). There must be 10-20 times more reflux than condensate for separation into components to be effective.
Pros and cons of the method
If rectification is carried out correctly (and this is a set of parameters that you need to know theoretically and apply in practice, adjusting to your needs), you get at home:
- rectified alcohol, suitable for internal use, pure, strength 96°;
- Considering that you use raw alcohol obtained from sugar or plant materials, the resulting alcohol is often higher in quality than that produced by industry;
- the resulting alcohol is an excellent alcohol base for various liqueurs.
- Most modern household water dispensers provide the possibility of not only rectification, but also distillation. Therefore, during the first distillation, use a distiller, and during the second, a rectifier.
Flaws:
- rectified alcohol produced at home is devoid of the smell of raw materials;
- like those produced at distilleries, it has a dry taste and requires softening and improving the taste quality. What, in fact, is invariably done in the production of vodka;
- low distillation speed, which lengthens the distillation process and requires greater energy consumption for heating and water for cooling;
- It is difficult to correctly determine when it is time to select tails. This requires practice.
What is a distillation column?
An indispensable device for those who want to drink their own and treat guests to homemade alcohol that does not contain harmful impurities.
By appearance- a tall pipe installed vertically above the distillation cube, turning into a reflux condenser with a flow-through condenser.
The alcohol selection device is located approximately at the height of 2/3 of the column. Often has its own cooler.
Properties
The distillation column has special capabilities that differ from a conventional moonshine still. It's created to strengthen and simultaneously cleanse impurities alcohol-containing liquid (or raw alcohol). The higher the column pipe, the more heavy impurities it can return back to the column and prevent them from entering the final product.
The design of the refrigerant and its properties make it possible to obtain alcohol with a strength of 96° at home. And this is a reality available to everyone who follows the recommendations for use given in the instructions for the column.
Principle of operation
- Pour alcohol-containing liquid into the distillation cube. The optimal strength is considered to be about 40°, that is, the column works most efficiently if raw alcohol is poured into it. But often distillers also use mash.
Attention. A better effect can be achieved in terms of strength and purity if the mash is distilled twice in a distillation column. The second time it will be raw alcohol.
- Check the tightness of the connections, connect the cold water supply/discharge.
- Turn on the heat.
- Depending on the heating power, the “working for yourself” phase - when the vapors leave the cube and return back to it - lasts half an hour to an hour. The process of drainage of phlegm and the counteraction of vapors tend to achieve equilibrium.
- After the temperature has stabilized (for 10 minutes), heads containing volatile compounds, including extremely toxic methylene and aldehydes, are collected at the top of the column. The heads, at a temperature of about 70°C, fly away on their own through a tube connecting the column to the atmosphere.
Important. During the rectification process, substances are clearly separated and do not mix with each other, but are separated even with a slight (tenth of a degree) difference in boiling point. Therefore, other components except ethyl alcohol do not enter the distillation body.
- Fractions with high boiling points accumulate at the bottom of the column. Gradually, as the ethylene evaporates, they rise upward. And gradually they begin to flow into the refrigerator, and then into the receiving container. They are determined by temperature or smell and collected separately.
Experienced distillers advise collecting the tails in separate 100 ml containers if you need to return the characteristic organoleptic properties to alcohol. Add to a small amount, and when you achieve the desired aroma and taste, “transfer” the proportions to the entire mass.
Kinds
There are two main types of distillation columns:
- Disc-shaped. It is with the help of such structures that alcohol is produced in industrial conditions. There are also home options. The advantage of this type is its subtle separation into fractions, as a result of which the home rectified product is completely devoid of fusel. The disadvantage is the bulkiness of the design.
- Attachments. Conventionally, they are divided into:
- irregular. Randomly (in bulk) filled with inert material (SPN), which are most often made at home or ready-made metal scourers-scrapers. Columns with them are lighter in weight and provide greater contact of vapors with reflux. But due to the high resistance, difficulties arise when separating vapors with reflux;
- regular. Here the nozzles are twisted Panchenkov on-load tap-changers and sheets with special perforation. They do not create excess pressure, facilitating the separation of substances.
How is it different from moonshine stills?
For clarity, we have made a special table, from which it is clear how different the two methods used to obtain strong alcohol in the kitchen are.
| Indicators | Rectification | Distillation |
| Alcohol produced | Rectified alcohol 96° | Moonshine, aromatic distillate (cereal, fruit, etc.) |
| Height of the assembled apparatus | From 85 cm to 1.5 meters | As a rule - up to 80-85 cm |
| Driving speed | From 650 ml on obsolete household columns to 2 liters per hour on modern ones | From 1 l/hour, if the device is low-productive, to 7-10 l/hour on high-quality factory-made units |
| Heating the cube | On various stoves, including induction (see specifications, may vary). For columns, it is often necessary to use a free-standing stove, since they do not fit under the hood of a standard kitchen. Possible options: heating element, steam generator, water boiler (cube in cube). | All of the options listed. The advantage of the distiller is its low height. You can always choose a device that will fit under the hood above a stationary stove. |
| Design features | Complex, consists of several modules. Requires a separate water connection to the dephlegmator. It is equipped with disc-type reflux condensers and nozzles for collecting reflux. | Simple. The direct-flow distiller is equipped only with a still and a refrigerator. Steamers and bubblers are used as additional canopies. |
| Safety | Careful monitoring of the temperature on both thermometers (on the cube and in the reflux condenser), pressure and other parameters is required, otherwise an explosion is possible. | Cannot be left unattended, but is not as exposed to risks as a rectifier. |
| Recyclable liquid | To ensure high-quality operation of the rectifier, the liquid must be clean of impurities, with a strength of 35 to 45°. It is better to distill not mash, but raw alcohol - in a distiller. Although it is not forbidden to work with mash. The main thing is that it is liquid and filtered. | Braga with a strength of no higher than 20°. When distilled in a still with a steam generator (water jacket), it can be thick. |
| Product purity | When distilled correctly, it is practically free of impurities. | High content of fusel oils even with double distillation. During distillation, it is impossible to select alcohol without impurities. |
| Amount of alcohol extracted | Up to 100%. No more than 1-2% is lost | Up to 80% |
How to choose?
Today's offers in specialized as well as online stores allow you to choose exactly the device that suits your needs.
Here are some tips to help you:
- Safety comes first. Therefore, take the material seriously as alembic, and columns. It must be inert and not react with the components of mash or raw alcohol. The best choice– stainless steel, and also – copper.
- Collapsible design. There are excellent, completely collapsible transforming devices that can also be used as distillers.
- Heating system. When working with a distillation column, a quick change of heating is necessary, so the best solution is a heating element with electronics. The worst is a gas stove.
- Performance. Average - 1 l/hour with heating 1 kW. Start from it.
Design
The apparatus – distillation column – must include:
- distillation cube Capacity from 12 liters, although the most popular ones are from 20 liters;
- drawer - a column (pipe with a diameter of 40-50 mm), up to 1.8 m high. It is the basis of the structure;
- The nozzle for the drawer is regular Panchenkov nozzles (often in combination with SPN springs). In everyday life, nets are also used for washing dishes;
- selection unit located in the middle part of the column. This is where the “body” accumulates - the pure alcohol fraction of 96-degree strength;
- a reflux condenser is a module with a separate refrigerator in which vapors are condensed and cooled. Here the qualitative separation of vapors into individual substances takes place;
- automation. Among the usual ones are a heating element thermostat, electronic thermometers, which you cannot do without, temperature alarms, etc. There are also fully automated columns, but this equipment is very expensive;
- flow-through refrigerator - for final cooling of alcohol vapor and turning it into the liquid phase;
- The pasteurization drawer is a new additional device that has relatively recently appeared on the distillery equipment market. It is installed above the drawer, in front of the reflux condenser. Allows you to obtain at one time a product comparable in quality to double rectification.
For example, the Dobry Zhar Mayak distillation column A small rating of devices with RC
In first place is Schnapser X2– universal system. Demountable, with clamp connections. German quality and 10 year warranty. Recommended for use on induction hobs. Cubes for 12 - 50 liters. Cost 10990 – 16990 rubles. For full rectification, you still need to buy a drawer with a height of 45 cm for 1590 rubles.
2nd place for the device "Good Heat" "Lighthouse" with cubes from 20 to 60 liters. Height – 178 cm. Cost: 19,600 -28,000 rubles. The design is collapsible. It can be operated in potstill mode to convert mash into raw alcohol, followed by rectification.
The question often arises: what is better: a distillation column or a moonshine still. There are many supporters of each device, but definitely having the Republic of Kazakhstan you can get good moonshine, but vice versa will not work. Rectification allows you to obtain pure alcohol with a strength of 96-98° from raw alcohol (moonshine). Good alcohol has practically no organoleptic properties, there is no smell of raw materials, the pure product can be used for the production of homemade vodkas and all kinds of liqueurs and tinctures. You can get such a product at home using a mini-distillery. Today it is quite easy to purchase a home mini-distillery in specialized stores. It is also possible to make a real distillation column yourself with your own hands.
In addition to technical skills, you must know the operating principle of this device, how a distillation column works. To produce alcohol, packed columns are used; they have small dimensions and easily fit in height in an ordinary apartment. The productivity of such a device reaches 300-1000 ml per hour, which is quite enough for home needs.
Distillation column - operating principle. As a nozzle for the column, various materials neutral to the action of alcohol are used - glass, stainless steel, ceramics. The main property of all nozzles is to wet and retain reflux on their surface. That is, alcohol vapor from the distillation cube rushing up the column, condenses at the top and returns down, flowing down the nozzle. An exchange of components occurs, alcohols rise up the column, and water and heavier impurities flow back into the distillation cube. When a stable distillation column enters operating mode, a balance occurs between the supply of steam and the selection of alcohol. The temperature in the column is stabilized and during the entire rectification process it remains at the same level, not exceeding 0.1-0.3 degrees. This mode can be maintained by good insulation of the column, supplying a specific power for each column and maintaining the required pressure in the system
Distillation column design
How to make a distillation column worries many home distillers. But you can make a small mini-distillery for your home yourself, saving a lot when purchasing a ready-made kit. The amount will be 2-3 times less if you decide to make a homemade distillation column. All details, how the distillation column is constructed and the drawing are described in detail below.
Each home mini-distillery consists of:
- Distillation cube;
- Tsarga;
- Nozzle;
- Selection unit;
- Dephlegmator;
- Fridge;
- Pasteurization drawer (optional);
- Automation.
Drawing diagram of a distillation column
Distillation cube. In another way, an evaporation cube, raw (moonshine) is poured into it for rectification. The cube is also a strong base for the column; the weight of the column with the nozzle is quite large. For domestic use, a capacity of 15-50 liters is usually used. The cube can be universally suitable for distilling mash and alcohol; in this case, it is advisable to use a large capacity of 30-50 liters. When making a cube, stainless steel beer kegs of 30 and 50 liters or food kettles are often used. The container must be equipped with a heating element, which is a heating element or two heating elements with a power of 1-3 kW. As a heating source, you can use an electric or induction stove with the ability to adjust the heating power. A thermometer is installed on the cube for internal monitoring of the still liquid. To reduce heat loss, it is recommended to insulate the cube from the outside.
Tsarga. The main, main part of any distillation column. All processes take place in it. The column for a home mini-distillery can be assembled from several connected parts (tsargs). It is better to make connections of all drawers using milk couplings or clamp connections. Such a system will be universal and can be used as a mash column for moonshine and a mini-distillery. For the drawer, a food grade stainless steel pipe with an internal diameter of 25-60 mm is used.
The distillation column for a moonshine still, which produces alcohol NDRF (under-rectified with a strength of 94-95°) can be made of copper. The diameter of the column must be selected approximately 25mm - 0.5 kW, 32mm - 1 kW, 38mm - 1.5 kW, 50mm - 2.5 kW. The length of the packed part of the distillation column should be 30-50 diameters, i.e. if the internal diameter of the pipe is 50 mm, then the height should be 1500 - 2500 mm. The higher the column, the better the exchange of vapor and liquid occurs in it, and as a result, the purer the alcohol. The wall thickness is preferably no more than 1 mm. 
The column requires careful thermal insulation. The insulation for pipes has proven itself well; the drawer can also be insulated using other methods by winding twine around the pipe and wrapping it with foil tape on top. The better the thermal insulation, the more stable the column will operate. You need to make a seat for the thermometer 20-30 cm from the bottom of the nozzle. 
This can be done by soldering a tube of the required diameter to the drawer. Or weld a sleeve under the sensor or thermometer. Stainless steel and a high-quality argon welder are not always available, so a distillation column for alcohol can be soldered from copper fittings. It is very easy to solder a rectification column from plumbing fittings with your own hands; you can easily pick them up in specialized stores. 
Nozzle. Today, the highest quality nozzle is considered to be SPN (spiral-prismatic nozzle). It is made of stainless or nichrome wire, which should not react with alcohol and other distillation products. 
The price of the nozzle is high, but if desired, it is easy to wind it yourself. In order for the nozzle to stay in the pipe, a crosspiece made of a stainless steel electrode for welding is soldered at the bottom of the drawer, and 2-3 cm of wire (nichrome) is placed on it. The SPN nozzle is not tightly poured on top and another wire wad is inserted on top.
The second most effective nozzle can be called the RPN - Panchenkov nozzle; it is a mesh of wire wound into wads the diameter of your pipe. There are also ceramic Rashiga rings and glass balls. The simplest attachment is a stainless steel sponge, but the effectiveness of such a filler is very low. For a pipe 1.3 meters long with a diameter of 35 mm, you will need 16-18 pieces. washcloths.
Dephlegmator with RK selection unit.
The reflux condenser crowns the upper part of the river column. Alcohol vapor enters it and condenses, turning into liquid phlegm. Part of the liquid phlegm is returned down the nozzle, and part is discharged outside through the selection unit. The design of the reflux condenser can be different. The simplest to manufacture is considered to be a jacket or direct-flow reflux condenser. It is made of two pipes of different diameters, between which water circulates for cooling. Water is supplied from below, warm water comes out from above. The outer casing of such a reflux condenser can be made from an ordinary thermos. The diameter of the inner pipe is usually made the same as the packed column. At the top of any reflux condenser there is a TCA - a communication tube with the atmosphere. 
Another option is a dimrot reflux condenser. It is a piece of pipe (a continuation of the drawer) in the middle of which there is a spiral of a thin tube with a diameter of 6-10 mm through which coolant circulates. For a column with a diameter of 50 mm, the dimrot is wound from a 6 mm tube 3 meters long. The reflux condenser is 25-35 cm long. This design has a larger contact area between steam and liquid and is considered more efficient. 
And the third option is a shell-and-tube reflux condenser. Several thin tubes are welded into a large-diameter pipe in which vapor condensation occurs. The advantage of such a device is its versatility; it can also work as a distiller’s refrigerator. The second advantage of this type is low water consumption and large cooling area. The shell and tube can be made inclined, which reduces the height of the column, which is important for a home mini-distillery in apartments with low ceilings. 
Under the reflux condenser above the packing part there is a distillate selection unit in the distillation column. Typically its design consists of one or two partitions and an alcohol sampling tube. The partitions are welded or soldered into the drawer at an angle. A needle valve with fine adjustment or a Hoffmann clamp is installed on the selection tube to limit or increase the selection of fractions.
Pasteurization drawer. The pasteurization tsar makes it possible to more efficiently purify commercial alcohol from the main fractions. Which are formed in the upper part of the distillation column and the reflux condenser throughout the entire distillation process. The alcohol pasteurization frame complicates the design of the distillation column and may not be installed as a separate element, but it allows you to significantly improve the quality of the alcohol. A slow selection of heads is also carried out during the selection of rectified alcohol from the pasteurization chamber.
Fridge.
The alcohol at the outlet flows hot and in order to cool it, an additional refrigerator (before the cooler) is installed after the selection unit and the tap. You can purchase a ready-made glass refrigerator at medical equipment stores. 
Or make a homemade refrigerator from tubes like a jacket reflux condenser, but with smaller dimensions. The length of the refrigerator is approximately equal to the length of the reflux condenser or slightly longer. Water first enters the lower inlet of the refrigerator, then from the upper it goes to the reflux condenser. By adjusting the water flow with a tap, the desired indicators are achieved. 
Automation for distillation column.
The complex rectification process requires constant presence and supervision. 
Good automation makes it possible to carry out rectification without constant human participation in the process. It prevents “tails” from getting into the commercial alcohol and allows you to select the head fractions into a separate container. The rectification control unit, abbreviated as (BUR), will turn on the cooling water at the desired temperature, reduce the power during extraction and automatically reduce the extraction at the end. After collecting the tails, turn off the heating and water. The simplest option automation, a start-stop installation with a valve that stops sampling when the temperature in the column rises; after stabilizing the temperature, sampling resumes. It is cheaper to assemble automation for a home mini-distillery using Chinese components or purchase it on specialized forums.