DE102014108977A1 - Apparatus and method for drying gases - Google Patents

Abstract

Shown and described is a device for drying gases, in particular for drying natural gas, comprising: a gas inlet (2) for the flow of moist gas into the device (1), 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 (L1) for connecting the gas inlet (2) to the adsorption chambers (4, 5), an outlet line (L14) for connecting the gas outlet (3) the adsorption chambers (4, 5) and at least one regeneration line (L15, L11) for returning dry gas from the outlet conduit (L14) through at least one of the adsorption chambers (4, 5) into the inlet conduit (L1). Also shown and described is a method for drying gases, in particular for drying natural gas, with such a device (1). In order to achieve a particularly energy-efficient cooling of the regeneration stream, it is proposed to provide at least one cooling line (L3) for introducing moist gas from the inlet line (L1) into one of the regeneration lines (L15, L11).

Description

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 into the inlet conduit.

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 is gaining in importance. This may be natural gas in compressed form (CNG = compressed natural gas) or in 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. If adsorption dryers are removed from the moisture to be dried by a desiccant moisture. 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 dissipated in the form of heated water vapor. 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 in which the regeneration takes place "cold" (ie by pressure change) and adsorption dryers in which the regeneration, as described above, "warm" (ie by temperature change). The two methods described are also known as "PSA" (pressure swing adsorption) and "TSA" (temperature swing adsorption).

Classic adsorption dryers are for example from EP 0 382 937 A1 or the WO 02/05931 A1 known. 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 from the EP 0 382 937 A1 known dryer is used for the regeneration sucked ambient air (dash-dotted line in 1 of the EP 0 382 937 A1 ). The ambient air is heated prior to introduction into the regenerating adsorber during the first phase of regeneration ("drying"); during the second phase of the regeneration ("cooling"), however, the heater is switched off. Subsequently, the ambient air is again led out of the dryer, which is why one can speak of an "open" Regenerationskreslauf. An open one Although regeneration cycle allows a relatively simple construction of the dryer, but has the disadvantage that the regeneration of the desiccant is not very effective. This is due in particular to the fact that the ambient air sucked in for regeneration was not dried. however, the more moist the aspirated ambient air is, the less moisture it can remove from the desiccant in the regenerating adsorber.

The from the WO 02/05931 A1 known 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") can be carried out in a closed circuit. For this purpose, the regeneration circuit is closed by a corresponding valve position, the heater is switched off and a cooler is switched on, which cools the circulating ambient air in the second phase of the regeneration. Another disadvantage of this dryer, the rather low 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 in which ambient air is sucked in for regeneration ("open regeneration cycle"), adsorption dryers are also known in which a partial flow of an already dried medium is diverted and used for regeneration ("closed regeneration cycle"). Such dryers are for example from the DE 10 2010 011 347 A1 or the DE 10 2006 023 161 A1 known.

In the from the DE 10 2010 011 347 A1 known dryer, the biomethane to be dried is first cooled by two arranged on the inlet pipe heat exchanger and the case this leaving water 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 from the outlet line after it leaves the adsorber and returning it to the adsorbers to be regenerated through a branch line and two further heat exchangers, and then returning it 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. However, the disadvantage is the structurally complex and energy-intensive heating or cooling of the regeneration flow through two heat exchangers. A heater is required even with "open" regeneration cycles; However, it is often possible to dispense with an additional cooler, since the ambient air sucked in for regeneration is already cool enough when the dryer is set up accordingly.

The from the DE 10 2006 023 161 A1 known dryer has a comparable operation. Also in this dryer is proposed to divert from the already dried medium a partial flow and use 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. Also in this 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 is precluded by increased design complexity and increased expenditure of energy for operating the two heat exchangers, in particular the additional cooler.

The invention is therefore based on the object, the above-described and previously described apparatus for drying gases in such a way and further develop that a particularly energy-efficient cooling of the regeneration stream 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 the regeneration of the desiccant takes place simultaneously in another adsorption chamber. After a certain time, both adsorption chambers exchange their function, so that an uninterrupted drying is possible. The apparatus further comprises an inlet conduit and an outlet conduit, the inlet conduit providing communication between the gas inlet and the adsorption chambers, and the outlet conduit providing communication between the gas outlet and the adsorption chambers. The inlet pipe and the Outlet line can make the appropriate connections alone or supplemented by other lines. 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. A "wet gas" is a gas that has not yet flowed through one of the two adsorption chambers and thus has not dried there. The gas flowing into the device is therefore initially referred to as "moist gas". By contrast, "dry gas" refers to a gas which has already passed through at least one adsorption chamber and has been 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 exchanger or by certain thermodynamic effects (eg Joule-Thomson effect). The advantage of using the gas flowing into the device to cool the regeneration stream is that less (or no) energy has to 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 be done for example by installing a diaphragm or other obstacle in the cooling line. The Joule-Thomson effect presupposes an isenthalic pressure reduction, ie a pressure reduction in which 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. In order not to lose the achieved cooling of the gas flowing through the cooling line and to transfer as completely as possible to the regeneration flow, the throttle is arranged as close as possible in front of 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 Vorroknung the gas; the precipitated condensate can be diverted. Preferably, the separator is arranged in the flow direction of the moist gas behind the compressor and the heat exchanger.

For this embodiment, it is further proposed that the cooling line in the flow direction of the moist gas behind the compressor, the heat exchanger, and / or the deposition 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 is connected in the flow direction of the regeneration gas behind the regenerating adsorption chamber with the regeneration line. In the second phase of regeneration, also referred to as "cooling", the regeneration gas cools the desiccant in the regenerating adsorption vessel and for that reason heats up. Therefore, cooling the regeneration gas is particularly useful if it occurs after the regeneration gas again has escaped from the regenerating adsorption.

A further embodiment of the invention is characterized by a heater for heating the regeneration gas. For this embodiment, it is further proposed that the heater is arranged in the flow direction of the regeneration gas in front of the regenerating adsorption chamber on the regeneration line. In the first phase of the regeneration, which is also referred to as "drying", the regeneration gas should extract moisture from the desiccant in order to prepare it for a new adsorption process. The ability of gases to absorb liquids increases with the temperature of the gases. For this reason, a faster drying of the desiccant can be achieved by heating the regeneration gas. A heater should therefore be placed so that it can heat regeneration gas 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. For this embodiment, it is further proposed that the heat exchanger is arranged in the flow direction of the regeneration gas behind the regenerating adsorption chamber on the regeneration line. 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 can be, for example, a mist eliminator or drop filter. As a post-filter, for example, a particle 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 above-described object is achieved in that a partial stream of the moist gas is introduced before it enters the adsorbent adsorption chamber through a cooling line in the emerging from the regenerating adsorption regeneration gas stream.

As has already been described for the device, the regeneration flow is to be cooled by 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. The volume flow which flows through the cooling line can be, for example, 1% to 10% and in particular about 5% of the (total) volume flow of the inlet line. The advantage of this procedure is in turn that due to the use of the gas flowing into the device for cooling the regeneration stream less (or no) energy must be used for further cooling of the regeneration stream.

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) simultaneously with step e) or step f) takes place. These steps correspond to the process steps already described above, wherein the functions of the two adsorption chambers are reversed: Steps a) to c) describe adsorption in the first adsorption chamber and regeneration and pressure buildup in the second adsorption chamber, while steps d) to f ) describe an adsorption in the second adsorption chamber and a regeneration and a pressure build-up in the first adsorption chamber. The steps a) to c) are half a cycle; the steps a) to f) accordingly form a full cycle. The implementation of all process steps has the advantage of optimal utilization of both adsorption chambers, 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 has already been described above in connection with the device, a particularly intelligent cooling can be achieved by throttling taking advantage of an already existing pressure difference due to the Joule-Thomson effect. An additional cooling The regeneration current can therefore be energy-saving or completely absent.

In a further embodiment of the method, it is proposed that the moist gas flowing into the device be compressed and / or cooled and / or pre-dried before it enters the adsorbing adsorption chamber. 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. On the other hand, the subsequent cooling of the regeneration stream should ensure that the water vapor taken up by the regeneration gas can be condensed and separated before the dryer is switched over and the desiccant is used again for adsorption.

The invention will be described in more detail with reference to a drawing showing only a preferred embodiment. In the drawing show

1 an embodiment of a device according to the invention for drying gases,

2 the device off 1 when carrying out a first step of the process according to the invention for drying gases,

3 the device off 1 in the execution of a second step of the process according to the invention for drying gases,

4 the device off 1 in the execution of a third step of the process according to the invention for drying gases,

5 the device off 1 in the execution of a fourth step of the process according to the invention for drying gases,

6 the device off 1 in the execution of a fifth step of the process according to the invention for drying gases,

7 the device off 1 in the execution of a sixth step of the inventive method for drying gases, and

8th a flowchart of the method according to the invention in a schematic representation.

1 shows an embodiment of a device according to the invention 1 for drying gases. The device 1 includes a gas inlet 2 and a gas outlet 3 , as well as two adsorption chambers 4 . 5 , The gas inlet 2 is via an (inlet) line L1 with a compressor 6 and a heat exchanger 7 connected. Behind the compressor 6 and the heat exchanger 7 opens the line L1 in a first separator 8th , from the condensate via a condensate line L2, at which a valve V1 and a throttle D1 are provided, in a second separator 9 and from there via a condensate drain 10 from the device 1 can be led out. Behind the first separator 8th continues the line L1 into a pre-filter 11 , from which a cooling line L3 branches off, through which a partial flow can be derived from the line L1 via a valve V2 and a throttle D2. The line L1 splits 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 in a corresponding manner to the lower end of the adsorption chamber 5 leads. In line L6 are a valve V5 and a throttle disk 12 intended. The line L6 divides behind the throttle plate 12 in a line L7 and a line L8. The administration 17 leads via a check valve V6 on to the lower end of the adsorption chamber 4 while the line L8 via a check valve V7 in a corresponding manner to the lower end of the adsorption chamber 5 leads.

With the lower ends of the adsorption chambers 4 . 5 are further lines L9, L10 connected, located behind valves V8, V9 to a common first regeneration line 111 unite. The first regeneration line L11 leads to an optional heat exchanger 13 , which also has an optional engine 14 can be air cooled. In the further course of the regeneration line L11, the cooling line L3 opens into the regeneration line L11 and can initiate the partial flow of moist gas previously branched off from the line L1 into the regeneration line L11. After that leads the regeneration line L11 to the previously described separator 9 , with the likewise previously described condensate drain 10 Condensate from the device 1 can derive. Finally, the regeneration line L11 leads back into the inlet line L1. The regeneration line L11 leads directly behind the gas inlet 2 and in particular before the compressor 6 back into the inlet line L1.

From the top of the adsorption chamber 4 leads a line L12 through a check valve V10; accordingly, a line L13 leads from the top of the adsorption chamber 5 through a check valve V11. Behind the check valves V10, V11, the lines L12, L13 unite to an (outlet) line L14, at which a secondary filter 16 is arranged and finally to the gas outlet 3 leads. From line L14, a second regeneration line L15 branches off, passing through an expansion valve 17 , a throttle disc 18 and a heater 19 leads and then splits into the lines L16 and L17. The administration 116 leads via a check valve V12 on to the upper end of the adsorption chamber 4 while the line L17 via a check valve V13 corresponding to the upper end of the adsorption chamber 5 leads.

Depending on the position of the valves, all lines L1 to L17 are fundamentally suitable for flowing through gases and / or liquids in both directions.

In 2 is the device 1 out 1 shown in the execution of a first step of the method according to the invention for drying gases. In the in 2 In the situation shown, the valves V1, V2, V3, V9, V10 and V13 are open, while the valves V4, V5, V6, V7, V8, V11 and V12 are closed (solid representation). Due to this adjustment of the valves, the following operation of the device results 1 ; Moist gas, especially moist natural gas, passes through the gas inlet 2 into the inlet line L1 of the device 1 and flows through the compressor 6 and the heat exchanger 7 , In the compressor 6 There 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 in the heat exchanger 7 cooled again, leaving 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 is behind the heat exchanger 7 the first separator 8th arranged, the condensate separates from the gas flowing through it and thus performs a (pre-) drying of the gas. The condensate can pass through the valve V1 and the condensate line L2 from the separator 8th be derived. The gas flows out of the separator after exiting 8th continues through the inlet line L1 and meets the pre-filter 11 , which may be a mist eliminator. The pre-filter 11 has only one input, but two outputs and therefore also represents a branch, through which a partial flow of the gas can be diverted from the inlet line L1 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 L1. That through the separator 8th and the pre-filter 11 (Pre) dried gas continues to flow through the inlet line L1 and the opened valve V3 and enters the adsorption chamber 4 one. There is the wet gas through. in the adsorption chamber 4 arranged, hygroscopic desiccant moisture removed; this process step is therefore referred to as "adsorption".

After the humid gas in the adsorption chamber 4 Moisture was removed, the gas flows in a dry state through the line L12, the valve V10, the outlet 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 opening the check valve V10 while the check valves V11 and V12 are closed.

While in the in 2 left side adsorption chamber 4 The "adsorption" takes place in the in 2 right side adsorption chamber 5 the process step "regeneration (warm)" is carried out as a substep of the regeneration. This is done by the following procedure: A partial flow of the from 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 disk 18 and the heater 19 , Through the relaxation valve 17 a reduction of the pressure is achieved; through the heater 19 In contrast, 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 has. By heating the gas, its ability to absorb moisture increases sharply. That from the heater 19 Exiting gas continues to flow into the line L17, which through the also open check valve V13 finally into the second adsorption chamber 5 leads.

In the adsorption chamber 5 the heated gas removes moisture from the desiccant. This Process step is also referred to as "warm regeneration" and is part of the regeneration of the desiccant. Since the absorption capacity of the desiccant is limited, a regeneration phase must follow an adsorption phase before the desiccant can absorb moisture again. After the heated gas in the adsorption chamber 5 Moisture, the moist, warm regeneration gas flows through the line L10 and the open valve V9 in the first regeneration line L11. There, the regeneration gas first flows through the (optional) heat exchanger 13 , one by the engine 14 includes driven air cooling and to cool the regeneration gas. Behind the heat exchanger 13 the cooling line L3 hits the regeneration line L11. Shortly before the entry of the cooling line L3 into the regeneration line L11, a throttle D2 is provided in the cooling line L3, which greatly reduces the pressure of the gas flowing through the cooling line L3. 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 thus cooled partial flow of the gas flowing through the cooling line L3 is mixed with the regeneration gas flowing through the regeneration line L11 and thus serves to cool the regeneration gas. The regeneration gas has, for example, a pressure in the range of 2 bar to 20 bar and a temperature of 20 ° C to 30 ° C behind the junction of the cooling line L3 in the regeneration line L11.

In the further course of the regeneration line L11 is the second separator 9 arranged in the - behind the throttle D1 - and that of the first separator 8th coming condensate line L2 opens. That in the two separators 8th . 9 recovered condensate is via the common condensate drain 10 from the device 1 derived. The regeneration gas continues to flow through the regeneration line L11, which again meets the inlet line L1 and flows into it. That coming from the regeneration line L11. Regeneration gas is thus immediately behind the inlet 2 and in particular before the compressor 6 fed back to the inlet line L1.

3 shows the device 1 out 1 in the execution of a second step of the inventive method for drying gases. In the in 3 the situation shown is the position of the valves with respect to in 2 situation unchanged. Thus, the valves V1, V2, V3, V9, V10 and V13 are opened, while the valves V4, V5, V6, V7, V8, V11 and V12 are closed (solid representation). The main difference to the in 2 illustrated situation is that the heater 19 at the in 3 shown situation is turned off. Due to this setting of the valves, the following operation of the device results 1 : In the 3 left side adsorption chamber 4 is flowed through in the same way as in connection with 2 has been described. In the adsorption chamber 4 Thus, the process step "adsorption" still takes place. In contrast, the mode of operation of in 3 right side adsorption chamber 5 opposite to the 2 changed situation. Because of the branched off from the outlet line L14 and passed through the regeneration L15 partial stream of dry gas is in the heater 19 no longer heated and thus flows "cold" in the adsorption chamber 5 , The in the second adsorption chamber 5 The method step performed is therefore also referred to as "cold regeneration" and also represents a partial step of the regeneration of the desiccant.

4 shows the device 1 out 1 in the execution of a third step of inventive method for drying gases. In the in 4 In the situation illustrated, the valves V1, V2, V3, V5, V7 and V10 are open, while the valves V4, V6, V8, V9, V11, V12 and V13 are closed (solid representation). Compared to the in 3 So the situation shown in the 4 In the situation shown, the valves V5 and V7 have been opened while the valves V9 and V13 have been closed. Due to this setting of the valves, the following operation of the device results 1 : In the 4 left side adsorption chamber 4 is flowed through in the same way as in connection with 2 and 3 has been described. In the adsorption chamber 4 Thus, the process step "adsorption" still takes place. In contrast, the mode of operation of in 4 right side adsorption chamber 5 opposite the in 2 and 3 changed situations. Because of the shut-off valves V9 and V13, no regeneration gas from the regeneration line L15 more in the adsorption chamber 5 enter and through the regeneration line L11 can no longer regeneration gas from the adsorption chamber 5 escape. 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 L1 and the lines L6 and L8 enter the adsorption chamber 5 one. Because that in the adsorption chamber 5 inflowing gas due to the in 4 shown valve positions no possibility of exit from the adsorption chamber 5 has, it comes to a pressure increase in this adsorption chamber 5 , The in the second adsorption chamber 5 therefore carried out process step is also referred to as "pressure build-up".

5 shows the device 1 in the execution of a fourth step of the inventive method for drying gases. In the in 5 In the situation illustrated, the valves V1, V2, V4, V8, V11 and V12 are open while the valves V3, V5, V6, V7, V9, V10 and V13 are closed. This results in a situation symmetrical to that in 2 described situation, the functions of the two adsorption chambers 4 . 5 were swapped. In other words, finds in the adsorption chamber 4 the process step "warm regeneration" takes place while in the adsorption chamber 5 the process step "adsorption" takes place.

6 shows the device 1 in the execution of a fifth step of the method according to the invention for drying gases. In the in 6 presented situation are - as in 5 - Valves V1, V2, V4, V8, V11 and V12 are opened while valves V3, V5, V6, V7, V9, V10 and V13 are closed. The main difference to the in 5 illustrated situation is that the heater 19 at the in 6 shown situation is turned off. This results in a situation symmetrical to that in 3 described situation, the functions of the two adsorption chambers 4 . 5 were swapped. In other words, finds in the adsorption chamber 4 the process step "cold regeneration" takes place while in the adsorption chamber 5 the process step "adsorption" takes place.

7 shows the device 1 in the execution of a fifth step of the method according to the invention for drying gases. In the in 7 In the situation illustrated, the valves V1, V2, V3, V5, V7 and V10 are open, while the valves V4, V6, V8, V9, V11, V12 and V13 are closed (solid representation). This results in a situation symmetrical to that in 4 described situation, the functions of the two adsorption chambers 4 . 5 were swapped. In other words, finds in the adsorption chamber 4 the process step "pressure build-up" takes place while in the adsorption chamber 5 the process step "adsorption" takes place.

The in the 2 to 7 As a whole, the method steps illustrated form a cyclic method, so that reference to the in 7 shown sixth method step again in 2 shown, first process step follows.

In 8th Finally, a flowchart of the method according to the invention is shown in a schematic representation. First, the valve V3 of the adsorption chamber 4 open, so that there can take place the step "adsorption". The duration of this step may be, for example, about 20 minutes. During this time, the valve V4 remains the adsorption chamber 5 closed and the valves V9 and V13 are opened so that in the adsorption chamber 5 the process step "regeneration" can take place. The process step "regeneration" includes a "warm regeneration" (heater 19 turned on) and a subsequent "cold regeneration" (Heater 19 switched off). The duration of the "warm regeneration" may be, for example, 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 opening the valves V5 and V7 is in the adsorption chamber 5 the process step "pressure build-up" initiated. The duration of this step may be, for example, about 4 minutes. After these steps are completed, a switchover of the device 1 made by which the two adsorption chambers 4 . 5 exchange their functions. So now it's in the adsorption chamber 5 an about 20-minute "adsorption" takes place while in the adsorption chamber 4 first a "warm regeneration" (about 14 minutes, heaters 19 turned on), then a "cold regeneration" (about 2 minutes; 19 switched off) and finally a lasting about 4 minutes "pressure build-up" takes place. After these steps are completed, in turn, a switching of the device 1 made by which the two adsorption chambers 4 . 5 exchange their functions again.

LIST OF REFERENCE NUMBERS

1

contraption

2

gas inlet

3

gas outlet

4, 5

adsorption

6

compressor

7

heat exchangers

8, 9

separators

10

drain

11

prefilter

12, 18

throttle disc

13

heat exchangers

14

engine

16

afterfilter

17

expansion valve

19

heaters

L1 L17

management

V1-V13

Valve

D1, D2

throttle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0382937 A1 [0010, 0011, 0011]
• WO 02/05931 A1 [0010, 0012]
• DE 102010011347 A1 [0013, 0014]
• DE 102006023161 A1 [0013, 0015]

Claims (16)

1 Device for drying gases, in particular for drying natural gas, comprising: - a gas inlet ( 2 ) for the flow of moist gas into the device ( 1 ), - 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 (L1) for connecting the gas inlet ( 2 ) with the adsorption chambers ( 4 . 5 ), - an outlet line (L14) for connecting the gas outlet ( 3 ) with the adsorption chambers ( 4 . 5 ), and - at least one regeneration line (L15, L11) for returning dry gas from the outlet line (L14) through at least one of the adsorption chambers (L15) 4 . 5 ) into the inlet duct (L1), characterized by at least one cooling duct (L3) for introducing moist gas from the inlet duct (L1) into one of the regeneration ducts (L15, L11). Apparatus according to claim 1, characterized in that the cooling line (L3) has a throttle (D2). Apparatus according to claim 1 or 2, characterized by a compressor ( 6 ), a heat exchanger ( 7 ), and / or a separator ( 8th ), which in the flow direction of the moist gas between the gas inlet ( 2 ) and the adsorption chambers ( 4 . 5 ) is arranged. Apparatus 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 ( 8th ) is connected to the inlet pipe (L1). 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 (L11). Device according to one of claims 1 to 5, characterized by a heater ( 19 ) for heating the regeneration gas. Apparatus according to claim 6, characterized in that the heater ( 19 ) in the flow direction of the regeneration gas before the regenerating adsorption chamber ( 4 . 5 ) is arranged on the regeneration line (L15). Device according to one of claims 1 to 7, characterized by a heat exchanger ( 13 ) for cooling the regeneration gas. Apparatus 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 ) is arranged on the regeneration line (L11). Device according to one of claims 1 to 9, characterized by a pre-filter ( 11 ) for cleaning the device ( 1 ) inflowing moist gas and / or a secondary filter ( 16 ) for cleaning the device ( 1 ) discharged dry gas. Process 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) Adsorption of moisture from the gas by desiccant in the first adsorption chamber ( 4 b) regeneration of 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 the regenerating adsorption ( 5 ) exiting regeneration gas stream is introduced. 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) regeneration of 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). A method according to claim 11 or 12, characterized in that the partial flow in the cooling line (L3) is throttled. Method according to one of claims 11 to 13, characterized in that in the device ( 1 ) incoming wet gas before entering the adsorbent adsorption chamber ( 4 . 5 ) is compressed and / or cooled and / or pre-dried. Method according to one of claims 11 to 14, characterized in that the regeneration stream before entering the regenerating adsorption chamber ( 4 . 5 ) is heated. Method according to one of claims 11 to 15, characterized in that the Regeneration stream after leaving the regenerating adsorption chamber ( 4 . 5 ) is cooled.

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