EP3160618A1

EP3160618A1 - Device and method for drying gases

Info

Publication number: EP3160618A1
Application number: EP15723142.4A
Authority: EP
Inventors: Jürgen Timmler
Original assignee: Parker Hannifin Manufacturing Germany GmbH and Co KG
Current assignee: Parker Hannifin Manufacturing Germany GmbH and Co KG
Priority date: 2014-06-26
Filing date: 2015-04-27
Publication date: 2017-05-03
Also published as: WO2015197233A1; DE102014108977A1

Abstract

The invention relates to a device for drying gases, in particular for drying natural gas, comprising: a gas inlet (2) for the inflow of damp gas into the device (1), a gas outlet (3) for the outlet of dried gas out of the device (1), at least two adsorption chambers (4, 5) for receiving drying means, an inlet line (L1) for connecting the gas inlet (2) to the adsorption chambers (4, 5), an outlet line (L14) for connecting the gas outlet (3) to the adsorption chambers (4, 5), and at least one regeneration line (L15, L11) for recirculating dried gas from the outlet line (L14) into the inlet line (L1) through at least one of the adsorption chambers (4, 5). The invention additionally relates to a method for drying gases, in particular for drying natural gas, using such a device (1). In order to achieve a particularly energy-saving cooling of the regeneration flow, at least one cooling line (L3) is provided for introducing damp gas from the inlet line (L1) into one of the regeneration lines (L15, L11).

Description

Apparatus and method for drying gases

The invention relates to a device for drying gases, in particular for drying natural gas, comprising: a gas inlet for introducing moist gas into the device, a gas outlet for discharging dried gas from the device, at least two adsorption chambers for receiving desiccant, an inlet line for connecting the gas inlet to the adsorption chambers, an outlet conduit for connecting the gas outlet to the adsorption chambers, and at least one regeneration conduit for returning dry gas from the outlet conduit through at least one of the adsorption chambers in the

Inlet line.

The invention also relates to a method for drying gases, in particular for drying natural gas, with such a device. From practice many devices and methods for drying gases are known. One of the reasons for the need to dry gases is that gases are used as a working medium in many industrial processes and too high humidity can lead to corrosion of the pipelines. Due to the increasing demand for renewable energies to drive

Motor vehicles, the drying of natural gas gains in importance. This may be natural gas in compressed form (CNG = compressed natural gas) or in

act liquefied form (LNG = Liquefied Natural Gas). The drying of natural gas, however, places particular demands on the drying plant, since natural gas often contains impurities such as dust or oil.

For the drying of gases, different devices, or dryers, are used. For example, refrigeration dryers are known. Refrigeration dryers regularly have two heat exchangers, an evaporator and a condenser and extract moisture from the gas to be dried by cooling it below its dew point and then reheating it. For this purpose, moist gas is sucked in and passed through a cooling element (the so-called evaporator). In the evaporator, the gas is cooled down so far that the dew point of the gas is exceeded. Since cold gas can store much less moisture than warm gas, the moisture condenses and can be drained off.

In addition, adsorption dryers are known. In adsorption dryers, the moisture to be dried is removed by a desiccant. The gas to be dried is regularly passed for this purpose in an adsorption chamber which is filled with the desiccant. Due to the hygroscopic, so water attracting mode of action of the desiccant, the moisture is removed from the gas. After the adsorption process, the moisture must be removed from the desiccant again; This step is called regeneration. For this purpose, air is sucked in from the environment on a regular basis, heated to high temperatures and passed through the desiccant. Due to the high temperature, the moisture stored in the desiccant evaporates and is in the form of heated

Derived steam. So that the two steps of adsorption and regeneration can take place simultaneously, adsorption dryers with two or more adsorption chambers have prevailed: While adsorption takes place in one chamber, regeneration can take place in the other chamber.

Although adsorption dryers regularly require more energy than refrigeration dryers, they have the advantage over these that gases can be dried to a very low pressure dew point. Adsorption dryers can in turn be divided into two types:

Adsorption dryers, where the regeneration is "cold" (ie by pressure change) and desiccant dryers, where the regeneration is "warm" (ie by temperature cycling) as described above The two methods described are also referred to as "PSA" (pressure swing adsorption) and "TSA" (temperature swing adsorption = temperature swing adsorption) ) known.

Conventional adsorption dryers are known, for example, from EP 0 382 937 A1 or WO 02/05931 A1. The dryers described there are characterized by a relatively simple construction and an associated robustness. However, a disadvantage is the limited efficiency, which is mainly due to the fact that sucked for regeneration, undried ambient air is used. This results in relatively long regeneration times.

In the dryer known from EP 0 382 937 A1, ambient air sucked in for regeneration is used (dot-dashed line in FIG. 1 of EP 0 382 937 A1). The ambient air is heated prior to introduction into the regenerating adsorber during the first phase of regeneration ("drying"), while during the second phase of regeneration ("cooling") the heater is shut down. Afterwards, the ambient air is led out of the dryer again, which is why one can speak of an "open" regeneration cycle.One open regeneration circuit allows a relatively simple construction of the dryer, but has the disadvantage that the regeneration of the desiccant is not very effective In particular, because the ambient air sucked in for regeneration has not been dried, the more humid the intake ambient air is, the less moisture it can expose the desiccant to the desiccant

Remove regenerating adsorber.

The known from WO 02/05931 AI dryer already has some improvements. The regeneration should in turn comprise two phases: first, the sucked ambient air is heated before being introduced into the regenerating adsorber, later the heater is turned off. Subsequently, the ambient air is led out of the dryer again. An improvement is that the second part of the regeneration ("cooling") in a closed cycle

can be carried out. For this purpose, the regeneration circuit is closed by a corresponding valve position, the heater is switched off and a cooler is switched on, the circulating in the second phase of the regeneration

Ambient air cools. The disadvantage is also on this dryer the rather small

Effectiveness of the regeneration of the desiccant, which is particularly due to the fact that undried ambient air is used for regeneration.

In addition to these classic adsorption dryers, where for regeneration

Ambient air is sucked in ("open regeneration cycle"), too

Adsorption dryer known in which a partial flow of an already dried medium is diverted and used for regeneration ('closed regeneration cycle'). Such dryers are known for example from DE 10 2010 011 347 AI or DE 10 2006 023 161 AI.

In the dryer known from DE 10 2010 011 347 A1, the biomethane to be dried is first cooled by two heat exchangers arranged on the inlet line and the water which separates out in the process is discharged. Subsequently, the biomethane is dried in two adsorbers connected in parallel, each filled with adsorbents. The dried biomethane leaving the adsorbers can now be led out of the dryer. The regeneration takes place by branching off a part of the dried biomethane after leaving the adsorbers from the outlet line and through a branch line and through two further heat exchangers to be regenerated again

Adsorber is guided and then returned to the inlet line. The regeneration stream is heated by the first heat exchanger in the first phase of the regeneration and cooled by the second heat exchanger in the second phase of the regeneration. The use of already dried biomethane for regeneration improves the regeneration of the desiccant. The disadvantage, however, is the structurally complex and energy-intensive heating or

Cooling of the regeneration flow through two heat exchangers. A heater is indeed Even with "open" regeneration cycles required, but there can often be dispensed with an additional cooler, since the sucked for regeneration ambient air with adequate installation of the dryer is already cool enough .. The known from DE 10 2006 023 161 AI dryer has a similar operation It is also proposed in this dryer to divert a partial stream from the already dried medium and use it for regeneration After passing through the regenerating adsorption tank, the regeneration stream is to be mixed again with the moist air flowing into the dryer Two heat exchangers are provided on the regeneration line: a heater and a radiator. Due to the comparable mode of operation, there are also corresponding advantages and disadvantages: Improved regeneration results in an increased constructional effort and an increased expenditure of energy, for example to operate the two heat exchangers, in particular the additional radiator, contrary.

The invention is therefore the object of the initially described and previously described device for drying gases in such a way and further, that a particularly energy-efficient cooling of the

Regeneration current is achieved.

The device according to the invention is initially characterized by a gas inlet and a gas outlet. Moist gas can flow into the device through the gas inlet, and dried gas can flow out of the device through the gas outlet. Furthermore, at least two adsorption chambers are provided for receiving desiccant. By providing two or more adsorption chambers, the drying of the gas can take place in one adsorption chamber, while in another adsorption chamber the regeneration of the adsorption chamber simultaneously takes place

Desiccant takes place. After a certain time both swap

Adsorption chambers their function, so that an uninterrupted drying is possible. The device also includes an inlet conduit and a Outlet line, wherein the inlet line connects between the gas inlet and the adsorption chambers and wherein the outlet line a

Establishment of connection between the gas outlet and the adsorption chambers. The inlet conduit and the outlet conduit may make the respective connections alone or supplemented by further conduits. For regeneration, at least one regeneration line is provided, through which dry gas can be returned from the outlet line through at least one of the adsorption chambers and further into the inlet line. The term "moist gas" refers to a gas which has not yet passed through one of the two adsorption chambers and thus has not yet been dried there.The gas flowing into the device is therefore initially referred to as "moist gas" on the other hand, a gas that already has at least one

Adsorption chamber has flowed and dried there. According to the invention, it is proposed to provide at least one cooling line for introducing moist gas from the inlet line into one of the regeneration lines. This constructive measure is based on the idea of cooling the regeneration flow through a partial flow of the moist gas flowing into the device. The cooling can be achieved either by the fact that the moist gas already has a sufficiently low temperature or be achieved in that the guided through the cooling line partial flow is cooled by suitable measures. These measures may be cooling by a

Heat exchangers or by certain thermodynamic effects (e.g., Joule-Thomson effect). The advantage of using the device

inflowing gas for cooling the regeneration stream is that less (or no) energy must be used to further cool the regeneration stream. Another heat exchanger for cooling the regeneration stream is therefore not mandatory; However, it can be optionally provided and used in case of need with low power for additional cooling of the regeneration stream. According to one embodiment of the invention, it is provided that the cooling line has a throttle. A throttle is understood to mean a means for throttling the flow flowing through the cooling line. A throttling of the flow causes a pressure reduction, which leads to an expansion and a cooling of the gas ("Joule-Thomson effect") .The throttling can take place for example by the installation of an orifice or another obstacle in the cooling line.The Joule Thomson Effect requires an isenthalpe pressure reduction, so one

Pressure reduction, where the enthalpy of the gas does not change (H = const). This can be achieved, for example, by virtue of the fact that the cooling line-at least in the region of the throttle-is thermally insulated particularly well. To reach that

Cooling of the gas flowing through the cooling line not to lose again and to transfer as completely as possible to the regeneration flow, the throttle is arranged as close as possible before the junction of the cooling line in the regeneration line. Preferably, the distance of the throttle to the junction of the cooling line in the regeneration line is 20 cm or less.

A further embodiment of the invention is characterized by a compressor, a heat exchanger, and / or a separator, which is arranged in the flow direction of the moist gas between the gas inlet and the adsorption chambers. The compressor achieves compression of the inflowing, moist gas. The heat exchanger can be used both for heating and for cooling the inflowing, moist gas. Preferably, the heat exchanger is arranged downstream of the compressor in the direction of flow of the moist gas in order to cool the gas heated up as a result of the compression. By the

Separator can be done a predrying of the gas; the excreted

Condensate can be drained. Preferably, the separator is in

Flow direction of the moist gas behind the compressor and the

Heat exchanger arranged. For this training is further proposed that the cooling line in

Flow direction of the moist gas behind the compressor, the heat exchanger, and / or the separator is connected to the inlet line. A particular advantage is achieved if the cooling line branches off in the flow direction of the moist gas behind the compressor from the inlet line. Because behind the compressor, the moist gas has a particularly high pressure, which can be used in the cooling line to relax the gas. The previously described Joule-Thomson effect leads to a particularly strong cooling at a large pressure difference. By the cooling line also branches off in the flow direction of the moist gas behind the heat exchanger and the separator from the inlet line, it can also be achieved that the moist gas enters the cooling line already in a pre-cooled (through the heat exchanger) and pre-dried (through the separator) state ,

In a further embodiment of the invention, it is provided that the cooling line in the flow direction of the regeneration gas behind the regenerating

Adsorption chamber is connected to the regeneration line. In the second phase of regeneration, which is also referred to as "cooling", that cools

Regeneration gas, the desiccant in the regenerating adsorption and heats up for this reason. Therefore, a cooling of the regeneration gas is particularly useful if it takes place after the regeneration gas has exited again from the regenerating adsorption.

A further embodiment of the invention is characterized by a heater for

Heating up the regeneration gas. This training will continue

proposed that the heater is arranged in the flow direction of the regeneration gas before the regenerating adsorption chamber on the regeneration line. In the first phase of regeneration, also referred to as "drying," the regeneration gas is intended to extract moisture from the desiccant to prepare it for re-adsorption.The ability of gases to pick up liquids increases with the temperature of the gases By heating the regeneration gas, a faster drying of the desiccant can be achieved, a heater should therefore be arranged so that it can be heated Regeneration gas can heat up before it is passed into the regenerating adsorption chamber.

A further embodiment of the invention is characterized by a heat exchanger for cooling the regeneration gas. To this embodiment, it is further proposed that the heat exchanger in the flow direction of the

Regeneration gas behind the regenerating adsorption chamber at the

Regeneration line is arranged. As previously described, the regeneration gas absorbs water vapor from the desiccant in the regenerating adsorption vessel. A cooling of the regeneration gas is particularly useful after exiting the regenerating adsorption, so that the water vapor absorbed by the regeneration gas can be condensed and separated before the dryer is switched and the desiccant is used again for adsorption.

Finally, the device can advantageously be further developed by a pre-filter for cleaning the moist gas flowing into the device and / or a secondary filter for cleaning the dry gas flowing out of the device. The prefilter may be, for example, a

Droplet or droplet filter act. As a post-filter, for example, a particulate filter can be used.

The invention, in addition to the apparatus described above, also relates to a process for drying gases, in particular for drying natural gas, which comprises the following steps: a) adsorbing moisture from the gas by desiccant in the first adsorption chamber, b) regenerating the desiccant in the second adsorption chamber, and c) pressure build-up in the second adsorption chamber, wherein step a) takes place simultaneously with step b) or step c). In a method according to the preamble of claim 11, the object described above is achieved in that a partial flow of the moist gas before its entry into the adsorbent adsorption chamber through a cooling line in the emerging from the regenerating adsorption chamber

Regeneration gas flow is initiated.

As has already been described for the device, the

Regeneration stream are cooled by a partial flow of the incoming, moist, gas in the device. The cooling can be achieved either by the fact that the moist gas already has a sufficiently low temperature or be achieved in that the guided through the cooling line partial flow is cooled by suitable measures. The volume flow through the

Cooling line flows, for example, 1% to 10% and in particular about 5% of the (total) volume flow of the inlet line amount. The advantage of this

Procedure is again that, due to the use of the in the

Device incoming gas for cooling the regeneration stream less (or no) energy for further cooling of the regeneration stream must be used.

A further embodiment of the method provides the following further steps: d) adsorption of moisture from the gas by desiccant in the second adsorption chamber, e) regeneration of the desiccant in the first

Adsorption chamber, and f) pressure build-up in the first adsorption chamber, wherein step d) takes place simultaneously with step e) or step f). These steps correspond to the method steps already described above, wherein the

Functions of the two adsorption chambers are reversed: The steps a) to c) describe an adsorption in the first adsorption chamber and a

Regeneration and a pressure build-up in the second adsorption chamber, while the steps d) to f) adsorption in the second adsorption chamber and a regeneration and a pressure build-up in the first adsorption chamber

describe. Steps a) to c) represent half a cycle; the steps a) to f) accordingly form a full cycle. The execution of all

Process steps has the advantage of optimal utilization of both Adsorption, since at any time at least one chamber adsorbs moisture.

According to a further embodiment of the method, it is provided that the partial flow in the cooling line is throttled. As previously mentioned in connection with the

Device has been described, can be achieved by throttling taking advantage of an already existing pressure difference due to the Joule-Thomson effect, a particularly intelligent cooling. An additional cooling of the regeneration stream can therefore be energy-saving or completely absent.

In a further embodiment of the method is proposed that in the

Device inflowing wet gas before entering the adsorbent

Adsorption chamber is compressed and / or cooled and / or pre-dried. These measures have also previously been discussed in more detail in connection with the device. The compression of the incoming, moist gas can be achieved by a compressor. A heat exchanger can do the cooling of the incoming, moist gas. Preferably, the cooling is carried out following the compression of the moist gas to cool the gas heated by the compression again. Pre-drying of the gas can be done by a separator. Pre-drying preferably takes place after compression and cooling of the moist gas.

Another teaching provides that the regeneration stream is heated before it enters the regenerating adsorption chamber. Alternatively or additionally, it is finally proposed that the regeneration stream is cooled after leaving the regenerating adsorption chamber. The heating of the

Regeneration stream has the consequence that the regeneration gas can absorb more moisture and thus dry the desiccant located in the regenerating adsorption chamber faster. The subsequent cooling of the regeneration current, however, should ensure that the of the

Regeneration gas absorbed steam condenses and separates can be before the dryer is switched and the desiccant is used again for adsorption.

The invention will now be described with reference to a preferred one

Embodiment illustrative drawing described in more detail. The drawing shows an embodiment of a device according to the invention for

Drying of gases,

FIG. 2 shows the device of FIG. 1 during the execution of a first step of the method according to the invention for drying gases;

3 shows the device of FIG. 1 in the execution of a second step of the method according to the invention for drying gases, FIG.

4 shows the device of FIG. 1 in the execution of a third step of the method according to the invention for drying gases, FIG.

5 shows the device from FIG. 1 in the execution of a fourth step of the method according to the invention for drying gases, FIG.

FIG. 6 shows the device from FIG. 1 in the execution of a fifth step of the method according to the invention for drying gases, FIG.

7 shows the device from FIG. 1 in the execution of a sixth step of the method according to the invention for drying gases, and a flow chart of the method according to the invention in a schematic representation. Fig. 1 shows an embodiment of a device 1 according to the invention for drying gases. The device 1 comprises a gas inlet 2 and a gas outlet 3, as well as two adsorption chambers 4, 5. The gas inlet 2 is connected via an (inlet) line LI with a compressor 6 and a heat exchanger 7. Behind the compressor 6 and the heat exchanger 7, the line LI opens into a first

Separator 8, from the condensate via a condensate line L2, at which a valve VI and a throttle Dl are provided, are passed into a second separator 9 and can be led out of there via a condensate drain 10 from the device 1. Behind the first separator 8, the line LI continues into a pre-filter 11, from which a cooling line L3 branches off, through which a partial flow can be derived from the line LI via a valve V2 and a throttle D2. The line LI divides behind the pre-filter 11 in a line L4, a line L5 and a line L6. The line L4 continues via a valve V3 to the lower end of the adsorption chamber 4, while the line L5 via a valve V4 leads in a corresponding manner to the lower end of the adsorption chamber 5. In line L6, a valve V5 and a throttle plate 12 are provided. The line L6 divides behind the throttle plate 12 in a line L7 and a line L8. The line L7 leads via a check valve V6 on to the lower end of the adsorption chamber 4, while the line L8 leads via a check valve V7 in a corresponding manner to the lower end of the adsorption chamber 5.

With the lower ends of the adsorption chambers 4, 5 lines L9, L10 are still connected, which unite behind valves V8, V9 to a common first regeneration line LH. The first regeneration line LH leads to an optional heat exchanger 13, which may be air-cooled via a likewise optional motor 14. In the further course of the regeneration line LH, the cooling line L3 opens into the regeneration line LH and can initiate the partial flow of moist gas previously diverted from the line LI into the regeneration line LH. Following this, the regeneration line LH leads to the previously described separator 9, which also has the previously described

Condensate drain 10 can drain condensate from the device 1. Finally leads the regeneration line LH back into the inlet line LI. The

Regeneration line LH leads directly behind the gas inlet 2 and in particular in front of the compressor 6 back into the inlet line LI.

From the upper end of the adsorption chamber 4, a line L12 passes through

Check valve V10; Accordingly, a line L13 leads from the upper end of the adsorption chamber 5 through a check valve VII. Behind the check valves V10, Vll, the lines L12, L13 combine to form an (outlet) line L14, at which a secondary filter 16 is arranged and which finally leads to the gas outlet 3. From the line L14 branches off a second regeneration line LI 5, by a

Relaxation valve 17, a throttle plate 18 and a heater 19 leads and then divides into the lines L16 and L17. The line L16 leads via a check valve V12 on to the upper end of the adsorption chamber 4, while the line L17 leads via a check valve V13 in a corresponding manner to the upper end of the adsorption chamber 5.

Depending on the position of the valves, all lines LI to L17 are in principle suitable for flowing through gases and / or liquids in both directions.

In Fig. 2, the device 1 of Fig. 1 in the execution of a first step of the method according to the invention for drying gases is shown. In the situation shown in Fig. 2, the valves VI, V2, V3, V9, V10 and V13 are opened, while the valves V4, V5, V6, V7, V8, Vll and V12 are closed (solid representation). Due to this setting of the valves, the following operation of the device 1 results: Moist gas, in particular moist natural gas enters through the gas inlet 2 in the inlet line LI of the device 1 and flows through the compressor 6 and the heat exchanger 7. In the compressor 6 is a strong compression of the gas, in which the gas heats up strongly. In order to remove the heat - at least partially - again, the gas is cooled in the heat exchanger 7 again, so that the gas behind the heat exchanger 7, for example, a pressure in the range of 200 bar to 300 bar and a temperature of 30 ° C to 50 ° C has.

Seen in the flow direction, the first separator 8 is arranged behind the heat exchanger 7, the condensate separates from the gas flowing through it and thus performs a (pre-) drying of the gas. The condensate can be discharged via the valve VI and the condensate line L2 from the separator 8. The gas, after exiting the separator 8, continues to flow through the inlet line LI and impinges on the prefilter 11, which may be a mist eliminator. The pre-filter 11 has only one input, but two outputs and therefore at the same time represents a branch through which a partial flow of the gas from the inlet line LI can be diverted and can be passed through the valve V2 and the cooling line L3. The volume flow which flows through the cooling line L3 may be, for example, about 5% of the (total) volume flow of the inlet line LI. The gas (pre-) dried by the separator 8 and the pre-filter 11 continues to flow through the inlet pipe LI and the opened valve V3 and enters the adsorption chamber 4. There is the humid gas through a in the

Adsorption chamber 4 arranged, hygroscopic desiccant moisture removed; this process step is therefore referred to as "adsorption".

After moisture has been extracted from the moist gas in the adsorption chamber 4, the gas flows in a dry state through the line L12, the valve V10, the outlet line L14, a post-filter 16 - for example a particulate filter - and finally through the gas outlet 3 from the device 1 out. This is accomplished by having the check valve V10 open while the check valves VII and V12 are closed.

While the "adsorption" takes place in the adsorption chamber 4 shown on the left in FIG. 2, in the adsorption chamber 5 shown on the right in FIG. 2, the process step "regeneration (warm)" is described as a partial step of the regeneration

carried out. This is done by the following procedure: A partial flow of the Adsorption chamber 4 exiting - and thus dry - gas is diverted from the outlet line L14 and passed into the second regeneration line L15. The volume flow which flows through the second regeneration line L15 may be, for example, about 3% of the (total) volume flow of the outlet line L14. There, the gas flows through the expansion valve 17, the throttle plate 18 and the heater 19. By the expansion valve 17, a reduction of the pressure is achieved; by the heater 19, however, a heating of the gas is achieved, so that the gas behind the heater 19, for example, a pressure in the range of 2 bar to 20 bar and a temperature of 70 ° C to 80 ° C. By heating the gas, its ability to absorb moisture increases sharply. The gas exiting from the heater 19 continues to flow into the line L17, which through the also open check valve VI 3 in the second

Adsorption chamber 5 leads. In the adsorption chamber 5, the heated gas extracts moisture from the desiccant. This process step is also called "warm regeneration" and is part of the regeneration of the desiccant

Absorption capacity of the desiccant is limited, must after a

Adsorption phase followed by a regeneration phase before the desiccant can absorb moisture again. After the heated gas in the

Adsorption chamber 5 has absorbed moisture, the moist, warm regeneration gas flows through the line L10 and the open valve V9 in the first regeneration line LH. There, the regeneration gas first flows through the (optional) heat exchanger 13, which is driven by the motor 14

Includes air cooling and the regeneration gas to cool. Behind the

Heat exchanger 13 strikes the cooling line L3 on the regeneration line LH. Just before the entry of the cooling line L3 in the regeneration line LH is in the

Cooling line L3 provided a throttle D2, which greatly reduces the pressure of the gas flowing through the cooling line L3 gas. Due to the "Joule-Thomson effect", the pressure reduction results in a strong cooling of the gas in the area of the throttle D2, the partial flow of the gas through the cooling line L3 cooled in this way flowing gas is mixed with the regeneration gas flowing through the regeneration LH and thus serves to cool the regeneration gas. The regeneration gas has behind the junction of the cooling line L3 in the

Regeneration line LH, for example, a pressure in the range of 2 bar to 20 bar and a temperature of 20 ° C to 30 ° C.

In the further course of the regeneration line LH, the second separator 9 is arranged, into which - behind the throttle Dl - also coming from the first separator 8 condensate line L2 opens. The condensate obtained in the two separators 8, 9 is discharged from the device 1 via the common condensate drain 10. The regeneration gas continues to flow through the

Regeneration line LH, which again meets the inlet line LI and opens into this. The regeneration gas coming from the regeneration line LH is therefore fed back into the inlet line LI directly behind the inlet 2 and in particular in front of the compressor 6.

Fig. 3 shows the device 1 of Fig. 1 in the execution of a second step of the method according to the invention for drying gases. In the in Fig. 3rd

The situation shown is the position of the valves relative to that in FIG. 2

situation unchanged. Thus, the valves VI, V2, V3, V9, V10 and V13 are opened, while the valves V4, V5, V6, V7, V8, VII and V12 are closed (solid representation). The essential difference from the situation shown in Fig. 2 is that the heater 19 is turned off in the situation shown in Fig. 3. Because of this adjustment of the valves, the following mode of operation of the device 1 results: The adsorption chamber 4 shown on the left in FIG. 3 flows through in the same way as was described in connection with FIG. 2. In the adsorption chamber 4 takes place

On the other hand, the mode of operation of the adsorption chamber 5 shown on the right in Fig. 3 is changed compared to the situation illustrated in Fig. 2. For the partial stream branched off from the outlet line L14 and conducted through the regeneration line L15 dry Gas is no longer heated in the heater 19 and thus flows "cold" into the adsorption chamber 5. The process performed in the second adsorption 5 process step is therefore also referred to as "cold regeneration" and also represents a partial step of the regeneration of the desiccant.

Fig. 4 shows the device 1 of Fig. 1 in the execution of a third step of the method according to the invention for drying gases. In the in Fig. 4

In the situation shown, the valves VI, V2, V3, V5, V7 and V10 are open, while the valves V4, V6, V8, V9, V11, V12 and V13 are closed (filled

Presentation). In comparison with the situation shown in FIG. 3, therefore, in the situation illustrated in FIG. 4, the valves V5 and V7 have been opened while the valves V9 and VI3 have been closed. This setting of the valves results in the following operation of the device 1 : The left in Fig. 4 shown

Adsorption chamber 4 is flowed through in the same manner as in the

Connection with Fig. 2 and Fig. 3 has been described. The method step "adsorption" thus still takes place in the adsorption chamber 4. In contrast, the mode of operation of the adsorption chamber 5 shown on the right in Fig. 4 is changed compared to the situations shown in Fig. 2 and Fig. 3. Because valves V9 and V13 can not change from the regeneration line L15

Regerationsgas more enter the adsorption 5 and through the

Regeneration line LH can no longer regeneration gas from the

Exude adsorption chamber 5. The regeneration of the desiccant in the

Adsorption chamber 5 is therefore finished. Instead, due to the opening of the valves V5 and V7, gas from the inlet line LI and the lines L6 and L8 enter the adsorption chamber 5. Since the gas flowing into the adsorption chamber 5 has no possibility of leaving the adsorption chamber 5 due to the valve positions shown in FIG. 4, a pressure increase occurs in the latter

Adsorption chamber 5. The process performed in the second adsorption 5 process step is therefore also referred to as "pressure build-up". Fig. 5 shows the device of Fig. 1 in the execution of a fourth step of the method according to the invention for drying gases. In the in Fig. 5th

The valves VI, V2, V4, V8, VII and V12 are opened while the valves V3, V5, V6, V7, V9, V10 and V13 are closed. In this way, a situation arises which is symmetrical to the situation described in FIG. 2, wherein the functions of the two adsorption chambers 4, 5 have been reversed. In other words, in the adsorption chamber 4, the process step "warm

Regeneration "takes place while in the adsorption chamber 5, the process step" adsorption "takes place.

Fig. 6 shows the device of Fig. 1 in the execution of a fifth step of the method according to the invention for drying gases. In the in Fig. 6

As shown in FIG. 5, the valves VI, V2, V4, V8, VII and V12 are opened while the valves V3, V5, V6, V7, V9, V10 and V13 are closed. The essential difference to the situation shown in Fig. 5 is that the

Heater 19 is turned off in the situation shown in Fig. 6. In this way, there is a situation that is symmetrical to the situation described in Fig. 3, wherein the functions of the two adsorption chambers 4, 5 were reversed. In other words, in the adsorption chamber 4, the process step "cold

Fig. 7 shows the device of Fig. 1 in the execution of a fifth step of the inventive method for drying gases. In the in Fig. 7

Presentation). In this way, a situation arises which is symmetrical to the situation described in FIG. 4, the functions of the

two adsorption chambers 4, 5 were reversed. In other words, the process step "pressure build-up" takes place in the adsorption chamber 4, while the process step "adsorption" takes place in the adsorption chamber 5. The method steps illustrated in FIGS. 2 to 7 overall form a cyclical method, so that the sixth one shown in FIG

Step again the illustrated in Fig. 2, the first step follows.

In Fig. 8, finally, a flowchart of the method according to the invention is shown in a schematic representation. First, the valve V3 is the

The duration of this step may, for example, be about 20 minutes During this time, the valve V4 of the adsorption chamber 5 remains closed and the valves V9 and VI3 are opened, so that in of the

The process step "regeneration" comprises a "warm regeneration" (heater 19 switched on) and an adjoining "cold regeneration" (heater 19 switched off). For example, the duration of the "warm regeneration" may be about 14 minutes, for example, the duration of the "cold regeneration" may be about 2 minutes. Following the two substeps of the regeneration, the regeneration cycle is interrupted by closing the valves V9 and V13, and the opening of the valves V5 and V7 initiates the step "pressure build-up" in the adsorption chamber 5. The duration of this step may be, for example, about 4 minutes. After these steps have been completed, the apparatus 1 is switched over, by means of which the two adsorption chambers 4, 5 exchange their functions, so that in the adsorption chamber 5 an "adsorption" of about 20 minutes takes place, while in the adsorption chamber 4 a first "Warm regeneration" (about 14 minutes;

Heater 19 is turned on), then a "cold regeneration" (about 2 minutes, heater 19 turned off) and finally a "pressure build-up" lasting about 4 minutes takes place. After these steps are completed, a switchover of the device 1 is again made, by which the two

Adsorption chambers 4, 5 exchange their functions again. LIST OF REFERENCE NUMBERS

1: device

2: gas inlet

3: gas outlet

4, 5: adsorption chamber

6: Compressor

7: heat exchanger

8, 9: separators

10: Condensate drain

11: Prefilter

12, 18: throttle plate

13: heat exchanger

14: engine

16: postfilter

17: Relaxation valve

19: heater

LI - L17: wire

V1 - V13: Valve

Dl, D2: Throttle

Claims

claims

Apparatus for drying gases, in particular for drying natural gas, comprising:

- A gas inlet (2) for the flow of moist gas into the device

- A gas outlet (3) for the discharge of dried gas from the

Device (1),

- At least two adsorption chambers (4, 5) for receiving

Desiccant,

- An inlet line (LI) for connecting the gas inlet (2) with the

Adsorption chambers (4, 5),

- An outlet (L14) for connecting the gas outlet (3) with the

Adsorption chambers (4, 5), and

- At least one regeneration line (L15, LH) for the return of

dry gas from the outlet conduit (L14) through at least one of the adsorption chambers (4, 5) into the inlet conduit (LI),

marked by

at least one cooling line (L3) for introducing moist gas from the inlet line (LI) into one of the regeneration lines (L15, LH).

Device according to claim 1,

characterized in that

the cooling line (L3) has a throttle (D2).

Apparatus according to claim 1 or 2,

marked by a compressor (6), a heat exchanger (7), and / or a separator (8) arranged in the flow direction of the moist gas between the gas inlet (2) and the adsorption chambers (4, 5).

Device according to claim 3,

characterized in that

the cooling line (L3) in the flow direction of the moist gas behind the compressor (6), the heat exchanger (7), and / or the separator (8) with the inlet line (LI) is connected.

Device according to one of claims 1 to 4,

characterized in that

the cooling line (L3) in the flow direction of the regeneration gas behind the regenerating adsorption chamber (4, 5) is connected to the regeneration line (LH).

Device according to one of claims 1 to 5,

marked by

a heater (19) for heating the regeneration gas.

Device according to claim 6,

characterized in that

the heater (19) is arranged upstream of the regenerating adsorption chamber (4, 5) on the regeneration line (L15) in the flow direction of the regeneration gas.

Device according to one of claims 1 to 7,

marked by

a heat exchanger (13) for cooling the regeneration gas.

Device according to claim 8, characterized in that

the heat exchanger (13) in the flow direction of the regeneration gas behind the regenerating adsorption chamber (4, 5) on the regeneration line (LH) is arranged.

10. Device according to one of claims 1 to 9,

marked by

a pre-filter (11) for cleaning the wet gas flowing into the device (1) and / or a post-filter (16) for cleaning the from the

Device (1) effluent dry gas.

11. A method for drying gases, in particular for drying natural gas, with an apparatus according to one of claims 1 to 10, comprising the following steps:

a) adsorbing moisture from the gas by desiccant in the first adsorption chamber (4),

b) regenerating the desiccant in the second adsorption chamber (5), and

c) pressure build-up in the second adsorption chamber (5),

wherein step a) takes place simultaneously with step b) or step c),

characterized in that

a partial stream of the moist gas before it enters the adsorbent

Adsorption chamber (4) through a cooling line (L3) in the from

regenerating adsorption chamber (5) exiting regeneration gas stream is introduced.

12. The method of claim 11, further comprising the steps of:

d) adsorbing moisture from the gas by desiccant in the second adsorption chamber (5),

e) regenerating the desiccant in the first adsorption chamber (4), and f) pressure build-up in the first adsorption chamber (4),

wherein step d) takes place simultaneously with step e) or step f).

Method according to claim 11 or 12,

characterized in that

the partial flow in the cooling line (L3) is throttled.

14. The method according to any one of claims 11 to 13,

characterized in that

the moist gas entering the device (1) is compressed and / or cooled and / or pre-dried before it enters the adsorbing adsorption chamber (4, 5).

15. The method according to any one of claims 11 to 14,

characterized in that

the regeneration stream is heated before entry into the regenerating adsorption chamber (4, 5).

16. The method according to any one of claims 11 to 15,

characterized in that

the regeneration stream after leaving the regenerating

Adsorption chamber (4, 5) is cooled.