DE941795C - Gas separation plant - Google Patents

Description

The invention relates to a gas separation plant with a gas separation column, which by means of a Cold gas refrigeration machine heat is withdrawn. Under a cold gas refrigerator there is a so-called to understand refrigerating machine operating according to the reverse hot gas engine principle. Such As is well known, machines can be designed in various ways, for example as displacement machines, as a double-acting machine, as a machine with V-shaped cylinders or as a machine whose working space is combined with that of the hot gas engine.

In general, it is desirable in gas separation columns to be able to provide a control by means of which is achieved that in operation and especially when there is a change in production of the Liquid level in the cooking vessel of the column is kept at the same level as possible. To this Purposes are often provided in the known gas separation systems, one or more taps with their Help the amount of washing liquid that flows down in the column can be changed. As a result is In the known systems, constant monitoring is desirable or necessary.

It has already been proposed to design a gas separation system so that steam from the column is discharged, which is condensed by a cold gas refrigerator, after which at least one

Part of the condensate generated by means of a vapor bubble pumping effect the column at one above the discharge opening of this condensate from the Cold gas refrigerator lying position is supplied. Because the gas separation column is generally the Cold gas refrigerator exceeds the height, must, if no special measures are taken, the point of the cold gas refrigerator at which the condensate is discharged, above the point ίο are where the condensate is fed to the column will. This is often undesirable for structural reasons. On the other hand, finds a vapor bubble pumping effect Application, the gas separation column and the cold gas refrigerator can be switched on and off the same substructure or at least be arranged in such a way that the position of the column where the Condensate must be fed, higher than the point at which this condensate from the cold gas refrigerator is discharged. A design was developed to match those described above Systems to regulate the supply of washing liquid automatically so that the liquid level remains as constant as possible in the cooking vessel.

According to the invention, in a plant in which steam is removed from the column, the is condensed by the cold gas refrigerator, after which at least part of the condensate of Column is supplied by means of a vapor bubble pumping action, at a point which is above the The discharge opening of this condensate from the cold gas refrigerator is the amount of the means of a Vapor pumping action of the condensate carried by the liquid level in the boiling vessel of the column depending on, while any remainder of the condensate is discharged from the refrigeration machine. An increase in the liquid level in the cooking vessel must be accompanied by a decrease in that of the column supplied amount of condensate go hand in hand, while a decrease in the level an increase in must result in the amount transported.

The plant described above can be used with success if the from the column escaping fraction with the lowest boiling point is condensed by the cold gas refrigerator is, with part of the generated condensate of the column by means of a vapor bubble pumping action and the rest is discharged from the refrigeration machine.

If, on the other hand, heat is removed from the gas separation column by means of an intermediate means, this Intermediate agent evaporates in a condenser of the column and the generated steam from the cold gas refrigerator is condensed, a different type can be used. According to a further embodiment of the invention, in In this case, the column is provided with at least two capacitors, each of which is a part of the generated Condensate is supplied by means of a vapor bubble pumping action, the amount of condensate supplied to each of these condensers is regulated as a function of the liquid level in the cooking vessel. With such a system is generally the product obtained, for example the fraction with the lowest boiling point, discharged from the column. One of them Condensers can essentially be used to condense the washing liquid and the other to Condensing that part can be used that can be discharged as the recovered product. the Changing the ratio between the amount of washing liquid generated and the amount of produced recovered product can be done that the vapor bubble pumping action in a or more of the leads to one of the capacitors is changed. When air-in Fractions is separated, nitrogen, for example, can be used as an intermediate agent.

According to a further embodiment of the invention, in which the fraction with the lowest Boiling point is condensed by a cold gas refrigerator, part of the condensate is means a vapor bubble pumping action of the column, while another part of the condensate also, Discharged from the system by means of a vapor bubble pump and this discharged Amount is regulated depending on the liquid level in the cooking vessel.

If the condensate is conveyed to the column by means of several vapor bubble pumps, can the vapor bubble pump function by switching on or off one or more of these Vapor bubble pumps can be increased or decreased. However, a simple design can be achieved if, according to a further embodiment of the invention, that by means of the vapor bubble pumping effect The amount of heat supplied to the liquid to be conveyed depends on the liquid level in the cooking vessel . depends on the column. In this embodiment, the effect of the vapor bubble pump can thus be changed by yourself.

The required amount of heat can be supplied in various ways, for example by means of a electric heating coil. The amount of heat supplied by the coil is then dependent adjustable from the height of the liquid level in the cooking vessel.

According to a further embodiment of the Invention, the heat is supplied by means of a body made of a material with a coefficient of thermal conductivity of at least 0.1 approx! l / cm see ° C ', of which a part has a higher temperature than the condensate, wherein means for changing, the temperature. ' this Part are provided. The metal body can be designed, for example, as a copper rod with one end is attached to the line through which the condensate to be conveyed flows, while the other end is held at a temperature exceeding that of the condensate so that heat can be supplied to the condensate through this rod.

The amount of heat supplied to the condensate by this rod can be changed in various ways will. According to one embodiment of the invention, the liquid is in the cooking vessel heat-exchanging contact with the metal

body. In this embodiment, when the level in the cooking vessel increases, the stick becomes more or less covered with liquid, so that more or less heat is added to the condensate will.

According to a further embodiment of the invention, the gas to be separated is in an outside The heat exchanger arranged in the cooking vessel is cooled, the body with this

ίο heat exchanger at a 'place in heat exchanger Touch is at a higher temperature than in the cooking vessel, while on a point on the body between the heat exchanger and the vapor bubble pump also the Liquid in the cooking vessel can be in heat-exchanging contact with this body.

According to a further embodiment of the invention, an overflow is provided on the cooking vessel, such that when the liquid level rises in the cooking vessel, more liquid with the body in heat-exchanging contact.

The invention is explained in more detail using a few exemplary embodiments.

Fig. Ι and 2 show a gas separation system in which by means of a metal body, an additional amount of heat is added to a part of the condensate to be conveyed is fed, the metal body at one end to the heat exchanger in which the to separating gas mixture is pre-cooled, is in heat-exchanging contact;

FIG. 2 is a line H-II of FIG. 1 guided cut; in the embodiment according to FIGS. 3 and 4, the metal body is in a heat-exchanging manner Contact with the agent in the cooking vessel of the gas separation column while the off the amount of medium discharged from the system is regulated by means of the heat supplied by this body; FIG. 4 is a line IV-IV of FIG. 3

guided cross-section; in

FIGS. 5 and 6 show a system in which a gas separation column is provided by means of an intermediate means Heat is withdrawn; here is

6 shows a cross section along the line VI-VI in FIG. 5.

The gas separation plant according to FIGS. 1 and 2 consists of a gas separation column 1 with a cooking vessel 2. The gas mixture to be separated is, after impurities have been removed from it, by a Line 3 is fed to a heat exchanger 4.

This heat exchanger is connected to the bottom 6 of the cooking vessel by means of a tubular support 5 2 connected, so that part of the heat withdrawn from the gas mixture to be separated over the support and the bottom provided with ribs 7 supplied to the liquid in the cooking vessel so that this liquid evaporates. The cooled gas mixture flows through the The annular channel 8 surrounding the cooking vessel 2 and the column 1 and passes through the openings 9 into the column. In this the gas mixture is separated into fractions. The liquid part of the fraction with the highest boiling point flows down the column and is collected in the cooking vessel.

The column is separated from the cooking vessel by means of a wall 10. There are in this wall a line 11 and an opening 12 with a smaller one Passage. The fraction with the highest boiling point flows through line 11 into the Cooking vessel; however, some of the steam generated in the cooking vessel rises through the opening 12 back up in the column. The resistance of the opening 12 is dimensioned so that in the cooking vessel there is a pressure which is higher than atmospheric pressure. This enables a part the steam generated in the cooking vessel via a line and the heat exchanger 4 from the Remove the cooking vessel. The steam flows through the one with inner and outer ribs Carrier 5, which is in heat-exchanging contact with the gas mixture to be separated, and leaves the system through a line 14.

The fraction at the top of the column with the lowest boiling point is passed through a line 15 and a line 16 of a cold gas refrigerator 17 is supplied. In this cold gas refrigerator the steam condenses. The refrigerating machine is driven by an electric motor 18. That generated Condensate is via the line 16 and a line 19 to a surrounding the column Annular channel 20 supplied. ·

As can also be seen in FIG. 2, three vertical lines 21, 22 and 23 connected. These lines are attached to the outer wall of the channel 8. This The gas mixture to be separated flows through channel 8, while the lines 21, 22 and 23 is the condensate of the fraction with the lowest boiling point. As a result of the temperature difference between the two means there is a vapor bubble pumping effect in this condensate, so that it is pumped up.

As a result, the condensate rises in lines 21, 22 and 23. Lines 21 and 22 open into the column, while line 23 removes the condensate from the system. For this purpose, the line 23 is connected to a line part 24 with a liquid seal 25. The line part 24 is so long that, as a result of the resulting negative pressure, the gas mixture to be separated is sucked in through the line 3, the heat exchanger 4 and the column. The lines 21 and 22 are by means of a metal strip 26 in heat-exchanging contact with a body 27 made of a material that is a good conductor of heat, for example copper. This metal body 2 ″ j is connected to the heat exchanger 4 in a thermally conductive manner, so that the temperature at this end is considerably higher than that of the condensate 27 at a point between its warm and cold end, the body having ribs 30 at this point.

The system works as follows: The gas mixture drawn in, for example air, flows after cleaning from steam and carbon dioxide

through the line 3, the heat exchanger 4 and the ring channel 8 to the column, in which it is divided into fractions is separated. In the cooking vessel 2, the fraction with the highest boiling point, in this case Trap oxygen, collected as the nitrogen escapes and from the top of the column the cold gas refrigerator 17 is condensed.

The condensate is fed to the lines 21, 22 and 23 via the line 19 and the annular channel 20. The condensate in the lines 21 and 22 is by means of the ring channel 8 flowing through Air and heat supplied by means of the metal body 27. Is the amount fed into the column Washer fluid too big, it rises

Liquid level in the cooking vessel, and as a result the liquid flows into the overflow 28 Space 29, as a result of which the rod 27 is cooled and less heat is thus supplied to the lines 21 and 22 will. It is of course important that the space 29 at such a distance from the warm end of the rod 27 is that the temperature at this point as a result of the temperature drop by the stick is higher than that of the liquid in the cooking vessel.

3 and 4, a further embodiment of the invention is shown on a larger scale. In these figures, the parts corresponding to FIGS. 1 and 2 are given the same reference numerals designated.

After the impurities have been removed from the gas mixture to be separated, this fed through the line 3 and then flows through the heat exchanger 4 and the annular channel 8 through to column r, as has been described for the plant according to FIG. the The fraction with the highest boiling point is collected in the cooking vessel 2 and evaporates in it. the Fraction with the lowest boiling point is condensed by a cold gas refrigerator, not shown, and the condensate is discharged from the refrigeration machine through line 19. These Line is similar to that shown in FIG System was the case, connected to a Rir-gkanal 20 with three lines 21, 22 and 23, in which a vapor bubble pumping action is maintained. The line 23 leads out condensate the system afy while the lines 21 and 22 feed the condensate to the column as scrubbing liquid. The cooking vessel has an overflow 28

do to a room 29. In this space 29 a metal body 40 is arranged which, like the body 2J of FIG. 1, is in heat-exchanging contact with the line 23 through which the condensate is discharged from the system.

The system works as follows: When the liquid level in the cooking vessel is low is, there is no liquid in the space 29, so that the line 23 has little or no heat is supplied via the metal body .40 and thus the vapor bubble pumping effect in the line 23 is not suggested. The system is designed so that in this case a relatively large amount of liquid is fed through the lines 21 and 22 of the column, whereby the The liquid level in the cooking vessel 2 rises. This continues until the liquid overflows 28 flows into room 29. As a result, heat is supplied to the metal body 40. This warmth will is fed to the line 23 via the metal body 40. As a result, the vapor bubble pumping effect in stimulated this line, so that more condensate is discharged from the system and the column less condensate is fed. The higher the liquid level in space 29 rises, the more Liquid is discharged from the column, and the less liquid enters the column. The body 40 is made of a thermally conductive material with a coefficient of thermal conduction greater than 0.1 cal / cm see ° C, for example from Copper.

In the plant according to FIGS. 5 and 6, the column is via a heat-transferring intermediate means Heat withdrawn. In the case of the system shown in these figures, too, those shown in FIGS and 2 corresponding parts are denoted by the same reference numerals.

The system is provided at the upper end with two capacitors 50 and 5 r, which are a heat transferring Intermediate means, for example nitrogen, can be supplied. The nitrogen evaporates so that heat is removed from the column and the steam is via lines 52 and 53 and a line 54 of the cold gas refrigerator 17 is supplied, in which it is condensed. The condensate is a column 1 surrounding a line 55 Ring line 56 supplied. There are four vertical lines 57, -58, 59 on this ring line and 60 connected in which a vapor bubble pumping action is exerted. The lines 57 and 58 are connected to capacitor 50 and lines 59 and 60 are connected to capacitor 51. The lines are to be separated by means of the gas mixture flowing through the ring channel 8 Heat supplied. The lines 57 and 58, however, also extend through a metal strip 61 in FIG thermally conductive connection to the metal body 27, through the, similar to Fig. 1, the lines Heat can be supplied.

Between. Capacitors 50 and 51, an annular channel 62 is provided in which the condenser 5.1 condensed agent largely collected and discharged through a line 63 from the system can be.

This system works as follows: The gas mixture to be separated, for example air, is fed to the column via line 3, heat exchanger 4 and annular channel 8. Of the liquid part of the fraction with the highest boiling point, for example oxygen, is in the cooking vessel collected, where it evaporates again, as described above with reference to FIGS has been. The vaporous part of the fraction with the lowest boiling point is in the condensers 50 and 51 condensed at the top of the column. Depending on the amount of heat that

Claims (9)

is withdrawn from each of the capacitors, from each of the capacitors a larger or less amount of steam generated. If a lot of heat is extracted from the steam by the condenser 51, then a large amount of condensate collected in the annular channel 62 and discharged from the system, so that the The amount of scrubbing liquid flowing back into the column is small. Will the capacitor 50 against it If a lot of heat is withdrawn, the amount of washing liquid is large. The amount of heat that the Capacitors is withdrawn, is dependent on the amount of liquid from the lines 57, 58 or 59, 60 is funded. If the amount of liquid in the cooking vessel is small, so that no liquid speed flows into the space 29 via the overflow 28, then, similar to that in FIG. 1, it becomes the case is, the lines 57 and 58 are supplied with a lot of heat, so that a lot of liquid is conveyed to the condenser 50 will. The amount of heat that the condenser ao sator 51 is withdrawn, is therefore low, while the amount withdrawn from the condenser 50 is large, so that little condensate from the system is discharged and a lot of condensate flows back as washing liquid. As a result, the the liquid level in the cooking vessel. In a certain way Moment liquid flows through the overflow 28 into the space 29, so that, similar to this on 1 has already been described, the lines 57 and 58 supplied less heat is so that the condenser 51 is supplied with liquid and more heat is withdrawn from it, so that more fluid is removed from the system is discharged. In this way, an equilibrium position of the liquid level results automatically. • In the embodiments shown above, the lines, in which a vapor bubble pumping action must be maintained, heat is supplied. It however, it is also possible to supply heat to these lines by means of an electrical heating coil. The amount of heat supplied in this way must then be dependent on the liquid level in the Cooking vessel can be regulated. Very often, however, the types shown in the drawing are because of preferable to its simplicity. SO PATENT CLAIMS: I. Gas separation system with a gas separation column that generates heat by means of a cold gas refrigerator is withdrawn, characterized in that steam is removed from the column, the is condensed by the cold gas refrigerator, after which at least part of the condensate by means of a vapor bubble pumping effect of the - Column on one. above the discharge opening of this Condensate is supplied from the cold gas refrigerator lying point, the on in this way transported amount of condensate from the liquid level in the boiling vessel of the column depends, and any remainder of the condensate is discharged from the refrigeration machine. 2. Gas separation plant according to claim 1, characterized characterized in that the fraction escaping from the column has the lowest boiling point is condensed by the cold gas refrigerator, with part of the generated condensate fed to the column by means of a vapor bubble pumping action and the remaining part out the refrigeration machine is discharged. 3. Gas separation plant according to claim, in which is withdrawn from the gas separation column by means of an intermediate 75 'by means of heat, the intermediate medium evaporated in a condenser of the column and the generated steam is condensed by the cold gas refrigerator, thereby characterized in that the column is provided with at least two capacitors, each of which is one Part of the generated condensate is supplied by means of a vapor bubble pumping action, wherein the amount of condensate fed to each of these condensers as a function of the liquid level is regulated in the cooking vessel. 4. Gas separation system according to claim 1 or 2, in which the fraction with the lowest boiling point is condensed by a cold gas refrigerator, characterized in that a part ^{p of} the condensate is fed to the column by means of a vapor bubble pumping effect, while another part of the condensate is also by means of a The vapor bubble pumping effect is removed from the system and this amount removed is regulated as a function of the liquid level in the cooking vessel. 5. Gastrennanilage according to any one of the preceding claims, characterized in that the Amount of heat supplied to the liquid to be conveyed by means of the vapor bubble pumping effect depends on the liquid level in the cooking vessel of the column. 6. Gas separation system according to claim 5, characterized in that the for the vapor bubble pumping effect required amount of heat is supplied by pipe. 7. Gas separation system according to claim 5, characterized in that the heat by means of a Body made of a material with a coefficient of thermal conductivity of at least 0.1 cal / cm see ° C is supplied, from which a Part has a higher temperature than the condensate, wherein means are provided. To the To change the temperature of this part. 8. Gas separation system according to claim 7, characterized in that the liquid in the cooking vessel is in heat-exchanging contact with the metal body. 9. Gas separation system according to claim 7 or 8, iao characterized in that the to be separated Gas is pre-cooled in a heat exchanger arranged outside the cooking vessel, while the body is at a point where the temperature exceeds that in the cooking vessel prevails with this heat exchanger stands in heat-exchanging contact while at one point on the body between the Heat exchanger and the vapor bubble pump also put the liquid in from the cooking vessel heat-exchanging contact with this body. ok Gas separation plant according to claim 8 or 9, characterized in that an overflow is provided on the cooking vessel so that when rising the liquid level in the cooking vessel means that more liquid is exchanged with the body in heat Touch stands. 1 sheet of drawings © 509 691 4.56