Adsorption dryer

Abstract

This method involves using an adsorption dryer to dry compressed gas, particularly compressed air. The adsorption dryer has at least one pressure vessel equipped with an adsorbent material for adsorbing moisture from the compressed gas. In the drying mode for drying the compressed gas, the compressed gas flows through the pressure vessel from the drying inlet through the drying section to the drying outlet, along with the adsorbent material, and flows out as dried compressed gas. In the regeneration mode for regenerating the adsorbent material, the regenerated gas flows through the pressure vessel from the drying outlet through the drying section to the drying inlet, along with the adsorbent material, during which moisture is removed from the adsorbent material. In the regeneration mode, partial heating occurs in a heating region within the pressure vessel, and the heating region is located only in a portion of the pressure vessel adjacent to the drying inlet.

Description

Technical Field

[0001] The present invention relates to a method for drying compressed gas and an adsorption dryer.

Background Art

[0002] Adsorption dryers are known and are used particularly for drying compressed air or other gases. All embodiments related to drying compressed air are also applicable to drying other gases.

[0003] For drying compressed air, an adsorption method is often used in which a compressed air stream is brought into contact with a solid adsorption material. The adsorption material absorbs a part of the water vapor contained in the compressed air stream and dries the compressed air. As a result, the amount of moisture bound (adsorbed) to the adsorption material increases. When the adsorption material has absorbed so much moisture that it can no longer sufficiently dry further compressed air, it is necessary to at least partially remove the contained moisture from the adsorption material before the adsorption material can be used again for drying compressed air. Removing moisture from the desiccant is called regeneration of the adsorption material. To technically achieve continuous drying, generally, a plurality of containers are provided, and when regenerating the adsorption material in one container, another already regenerated container is used for drying.

[0004] A method is known in which a part of the already dried compressed air is decompressed to a low pressure and induced to pass through the container in which the adsorption material is to be regenerated. At this time, the direction of the flow is usually opposite to the direction of the flow during drying of the compressed air. A dryer that functions in this way is called a low-temperature regeneration type adsorption dryer.

[0005] The partial pressure of water vapor in an airflow is considered to be at most equal to the water vapor pressure. This limits the partial density of water vapor in the air. Compressed air to be dried is usually 100% saturated with water vapor, meaning it has reached the water vapor pressure, and therefore the maximum possible partial density. If the temperatures during drying and regeneration are approximately the same, the volume of regenerated air must be at least the same as the volume of pre-dried compressed air. Therefore, the proportion of compressed air that must be depressurized must be at least the same as the pressure ratio during regeneration and drying, at approximately the same temperature. This is because, for an ideal gas, the density at approximately constant temperature is proportional to the pressure.

[0006] The drawback of this method is that a significant portion of the compressed air that is depressurized for regeneration becomes unavailable for further use, thus requiring compression in addition to the amount of compressed air actually needed. This results in a very high energy consumption for this method.

[0007] Further known methods for regeneration involve higher temperatures. Higher temperatures result in higher water vapor pressure. In this case, heated ambient air is used for regeneration. The temperature during regeneration is selected to ensure that the water vapor pressure significantly exceeds the partial pressure of water vapor in the ambient air. This allows for regeneration even though the ambient air already contains water vapor. Dryers operating in this manner are called thermal regeneration adsorption dryers.

[0008] This method requires heating the dry material to a high temperature, such as 150°C, through heated ambient air, and introducing enough heat to desorb moisture from the dry material. Desorption means that moisture that is bound (adsorbed) transitions to a gaseous state. The thermal energy required for this method is less than the energy required to produce the compressed air that is depressurized for regeneration using the method described above.

[0009] The drawback is that the drying material is hot at the end of the regeneration process. This means that the compressed air flows through the hot drying material immediately after switching containers. As a result, the compressed air is heated to an undesirable high temperature, and the drying efficiency also decreases because the higher the temperature of the drying material, the less moisture can be removed from the compressed air.

[0010] To mitigate this drawback, the dry material is cooled before being used again to dry the compressed air. Ambient air and / or depressurized compressed air can be used to cool the dry material. Cooling with ambient air is limited by the fact that the dry material has already absorbed water vapor from the ambient air during the cooling process, thereby reducing the amount of compressed air that can be used for drying. Cooling with depressurized compressed air can also be performed only on a very limited scale, if there is an energy advantage to be gained compared to regenerating with depressurized compressed air.

[0011] In other words, the drawbacks of high temperature and residual moisture immediately after switching to compressed air drying for the container can be mitigated to some extent, but cannot be completely avoided.

[0012] Patent Document 1 describes a drying method that uses reduced-pressure compressed air for regeneration, such as a low-temperature regenerative adsorption dryer. Before reducing the pressure of the compressed air, it is heated by the oil in an oil-injection screw compressor. This introduced heat improves desorption. However, the heat input is limited by the heat capacity of the regenerative air. Therefore, a considerable proportion of compressed air is still required for regeneration. In this case, the desiccant is heated after regeneration, and as mentioned above, a drawback is that this residual heat causes a significant increase in temperature and residual moisture after switching to drying.

[0013] Patent Document 2 also describes a similar drying method. However, in this method, to improve regeneration, each container is directly heated during regeneration by heated oil from an oil-injection screw compressor. Instead of using reduced-pressure compressed air for regeneration, it is proposed to draw in water vapor. However, if the water vapor pressure is low, this requires evacuating the container to a very low pressure.

[0014] An advantage over Patent Document 1 is that the heat input can be performed independently of the regenerated air. However, like Patent Document 2, a disadvantage is that residual heat is large.

[0015] In Patent Document 3, at least a portion of the drying material is heated by resistance heating or microwave heating, independently of compressed air. Here, the heating of the drying material is achieved by two or more independently operating heating devices, so that heating of the drying material in the upper part of the container can be terminated while heating is still taking place in the lower part of the container. This can reduce the amount of compressed air required for cooling to some extent. However, a large amount of cooling air is still required to cool the entire contents of the container. Adsorption buffers are described in Patent Document 4. Vacuum regeneration is described in Patent Document 5. [Prior art documents] [Patent Documents]

[0016] [Patent Document 1] U.S. Patent No. 5087178 [Patent Document 2] U.S. Patent No. 4898599 [Patent Document 3] European Patent No. 1010452 [Patent Document 4] U.S. Patent No. 3,204,388 [Patent Document 5] Korean Patent Publication No. 101214541 [Overview of the project] [Problems that the invention aims to solve]

[0017] Therefore, the object of the present invention is to address at least one of the above-mentioned problems. In particular, a method should be developed to keep energy demand as low as possible and to reduce the temperature and humidity of the compressed air after switching the regenerated container to compressed air drying. At the very least, a solution should be proposed that is an alternative to any known solution. [Means for solving the problem]

[0018] The present invention proposes a method according to claim 1, relating to the drying of compressed gas, particularly compressed air, using an adsorption dryer. Such an adsorption dryer has at least one pressure vessel equipped with an adsorption material for adsorbing moisture from the compressed gas. Such an adsorption material may be a suitable granular material placed inside the pressure vessel through which compressed air flows during operation.

[0019] In this method, in the drying mode, the compressed gas flows through the pressure vessel along the adsorbent material from the drying inlet through the drying section to the drying outlet in order to dry the compressed gas, and then flows out as dried compressed gas. In other words, the compressed gas flows through the pressure vessel along the adsorbent material, which may exist as particulate matter, and in the process, it releases moisture into the adsorbent material. That is, the dried compressed gas has less moisture immediately after it flows in through the drying inlet than it did before it flowed along the adsorbent material.

[0020] In particular, due to structural and / or functional challenges, it may not be possible to completely fill a pressure vessel with adsorbent material. In this case, the pressure vessel has transitional regions to the adsorbent material in the dry inlet and / or dry outlet areas, where the adsorbent material is not present. Each transitional region may occupy approximately 2% to 10% of the length from the dry inlet to the dry outlet. The dry section refers to the section within the adsorbent material, i.e., the section from the dry inlet to the dry outlet, minus at least one transitional region.

[0021] In the regeneration mode for regenerating the adsorbent material, the regeneration gas flows from the drying outlet through the drying section to the drying inlet along the adsorbent material inside the pressure vessel, and at this time, moisture is removed from the adsorbent material. Therefore, in the regeneration mode, the direction of flow is opposite to that in the drying mode, and the regeneration gas flows in the opposite direction to the compressed gas to be dried, and the moisture absorbed by the adsorbent material from the compressed gas to be dried is removed from the adsorbent material again.

[0022] Furthermore, in the regeneration mode, it is proposed to perform partial heating in the heating region inside the pressure vessel. That is, in the regeneration mode, the pressure vessel is heated, but not all regions are heated. At this time, the heating region is arranged only in a partial region of the pressure vessel adjacent to the drying inlet. Therefore, the regeneration gas first flows through the non-heated region inside the pressure vessel and then through the heating region.

[0023] The regeneration gas is heated by heating, whereby its water vapor absorption capacity is improved. As a result, more moisture can be absorbed. The adsorbent material heated thereby can also release more of its moisture.

[0024] However, it is recognized that the compressed air to be dried releases the most moisture in the region where the compressed air flows in, that is, near the drying inlet. Therefore, the adsorbent material basically has the highest moisture ratio near the drying inlet, and the moisture ratio decreases toward the drying outlet. The proposed method exactly utilizes this finding. In the regeneration mode, the regeneration gas first flows into the region of the pressure vessel where the adsorbent material has absorbed a relatively small amount of moisture. Furthermore, the regeneration gas itself is also very dry initially and has not absorbed any moisture or has not absorbed much moisture. Therefore, this relatively dry regeneration gas can absorb the small amount of moisture of the adsorbent material in the region of the drying outlet very well.

[0025] In this sense, the amount of moisture absorbed by the regenerated gas increases from the drying outlet towards the drying inlet. The regenerated gas absorbs a lot of moisture as it flows towards the drying inlet, but it still needs to absorb a lot of moisture from the adsorbent material. This is because the adsorbent material near the drying inlet contains a very large amount of moisture.

[0026] Therefore, the pressure vessel is heated in the region near the drying inlet. This heats the regenerating gas, especially the air, and increases its water vapor absorption capacity, allowing it to absorb more moisture.

[0027] However, it is proposed that this heating be carried out only in a specific area of ​​the pressure vessel. Heating is performed only where an increase in water vapor absorption capacity is required. As mentioned above, this is recognized to be the area of ​​the drying inlet.

[0028] It is also recognized that it is particularly advantageous for dry air to flow in one direction and regenerated gas to flow in the opposite direction. The flow direction of the compressed gas to be dried creates a corresponding gradient of absorbed moisture within the pressure vessel, and regenerated gas flowing in the opposite direction is well suited to this gradient, especially by intensively heating the regenerated gas before it is discharged.

[0029] Therefore, by concentrating heat input where it is needed to improve efficiency, the method can be improved compared to prior art. During drying, most of the water vapor is already adsorbed in the lower part of the pressure vessel if the pressure inlet is located in the lower part of the vessel. By concentrating heat input in this lower part of the vessel, through which the regenerated air flows just before it flows out of the vessel, the water vapor absorption capacity of the regenerated air increases only where a higher capacity is needed. This is because it is only at this location that a large amount of moisture can be released into the air. Unnecessary heating of a large amount of the drying material is avoided.

[0030] In one embodiment, it is proposed that the heating region be located in the 0% to 80% portion of the drying section, preferably 0% to 60%, and particularly 0% to 50%. Therefore, the heating region is provided in the area surrounding the drying inlet.

[0031] In addition to this, or instead, it is proposed that the heating region extends over at least 20%, preferably at least 30%, and particularly at least 40% of the drying section. Specifically, it is stipulated that heating is not performed outside the heating region, or in some cases, heating is performed outside the heating region with an energy input per unit volume reduced to less than 30%.

[0032] It is recognized that heating approximately half of the drying section, i.e., the half on the drying inlet side, is particularly advantageous. Therefore, the heating area is located near the drying inlet. The heating area is within the 0% to 80% portion, and therefore not within the 80% to 100% portion. For the reasons mentioned above, this portion remains free and does not need to be heated. However, it is also recognized that heating in the 0% to 60% range may be sufficient. The 0% to 50% range is particularly preferable because it can heat approximately half of the drying section. The pressure vessel can be installed vertically, for example, with the drying inlet at the bottom and the drying outlet at the top. In such a generally cylindrical vessel, the adsorbent material, or the frame that receives the adsorbent material, can be installed inside the pressure vessel, for example, on the legs, so that the adsorbent material, and thus the starting point of the drying section, is located at a distance of approximately 5% from the drying inlet.

[0033] In this case, or alternatively, it is proposed that the heating region extends over at least 30%, particularly at least 40%, of the drying section, preferably located in the 0% to 80%, 0% to 60%, or 5% to 50% portions mentioned above. This allows a considerable area of ​​the drying section, i.e., at least 30%, to be heated. A higher regeneration effect can be obtained through a wider area of ​​40% or more, but this may lead to higher energy input. The heating region should not extend over the entire drying section, and therefore preferably extend over a maximum of 70%, particularly a maximum of 60%, of the drying section.

[0034] Heating should not be performed outside the heating zone. Therefore, no heating is performed outside the heating zone throughout the entire regeneration mode. In principle, it may be considered that heating is possible with an energy input per unit volume reduced to less than 30% compared to the heating zone. However, the energy input per unit volume may also be less than 10% compared to the heating zone. In principle, heating outside the heating zone is not provided, but if for other reasons heating that may be provided for the drying mode needs to be performed outside the heating zone, it is impossible to eliminate this, but this should be avoided as much as possible as it will only result in undesirable energy input.

[0035] According to one embodiment, the compressed gas fraction, which is the dried portion of the compressed gas, is used as a regenerated gas, the compressed gas fraction at the drying outlet is introduced into a pressure vessel, and the compressed gas fraction is depressurized when introduced into the pressure vessel or before introduction.

[0036] This allows a portion of the dried compressed gas to be regenerated, i.e., used to dry the adsorbent material. A specific means of implementation is to use two pressure vessels, which can be operated alternately in drying mode and regeneration mode. When one pressure vessel is operating in drying mode, it continuously releases dry compressed air, which can then be used in the other vessel operating in regeneration mode to regenerate, i.e., dry the adsorbent material. The pressure is reduced so that this dried compressed gas, especially the dry compressed air, can absorb more moisture from the adsorbent material even in unheated areas. In other words, the compressed gas is dried at a higher pressure, but as the pressure decreases, it can reabsorb, so to speak, its own moisture from the adsorbent material.

[0037] This compressed gas fraction, after being used for regeneration, is discharged as moist gas or moist compressed air, and may no longer be pressurized or overpressurized, or some of its moisture is released again in a water separator. Such a water separator functions, for example, by condensation.

[0038] In one embodiment, heating inside the pressure vessel is performed by a heat exchanger, and it is proposed that the heat transfer portion of the heat exchanger is surrounded by the adsorbent material in order to release heat to the adsorbent material. However, even in regeneration mode, the heat exchanger directly releases heat to the regenerated gas, particularly the regenerated air.

[0039] Here, it is recognized that the use of a heat exchanger allows heat generated elsewhere in the system to be used to heat the pressure vessel. In this case, the heat exchanger has heat transfer sections located within the pressure vessel. These heat transfer sections are configured to be surrounded by an adsorbent material within the pressure vessel. In particular, the adsorbent material may be provided as a granular material, and therefore as a bulk material. In this case, the heat transfer sections are configured to be located within the pressure vessel so that such granular bulk material surrounds them. In particular, bulk material may or may not be supplied between the segments of the heat transfer section.

[0040] For this purpose, the heat transfer section may be, for example, in the shape of a cylinder disc, or a circular section or a plurality of flat sections arranged parallel to each other, and the heat transfer section is configured such that granular material is supplied around it, and in the sections arranged parallel to each other, there is sufficient space between them to supply the granular material.

[0041] Here, it is particularly recognized that heating of the regenerated gas occurs directly, that is, directly and indirectly, as the regenerated gas flows through these heat transfer sections. Indirectly, heating occurs when the adsorbent material surrounding the heat transfer section is heated, and then the regenerated gas is heated through the adsorbent material through which it passes, or through the adsorbent material through which it flows.

[0042] In one embodiment, it is proposed that compressed gas is generated by a pressurizing device, particularly a compressor, and that the waste heat from the pressurizing device is used to heat the heating area during regeneration. In particular, it is proposed that heated oil from an oil-injection screw compressor be used to heat the heating area during regeneration.

[0043] Here, it is particularly recognized that a large amount of heat is generated to produce the pressure of the compressed gas, and this heat can be effectively utilized for heating during regeneration. By using a small heating area that heats only a portion of the drying section, heating is carried out using such waste heat from the pressurizer or compressor, thereby improving the suitability of such heating areas and ensuring sufficient thermal energy is supplied. This makes it possible to efficiently configure a compressed air system having an adsorption dryer and a pressurizer.

[0044] In the use of an oil-injection screw compressor, the oil is heated due to the function of the screw compressor, and this oil is used for heating by a heat exchanger, and in particular, can be used as a liquid heat transfer medium in such a heat exchanger. The term heat transfer medium can also be used as a synonym for heat transfer medium.

[0045] In one embodiment, it is proposed to heat the heating region by utilizing the waste heat of the pressurizing device and active heating from an energy source, and in particular, to heat the heating medium so that the temperature of the heating medium heated by the waste heat is further raised to a predetermined temperature by active heating.

[0046] Therefore, heating of the heating region can utilize waste heat from the pressurizing device, especially the screw compressor, even when the waste heat from the pressurizing device alone is insufficient. Active heating can be supplemented by further heating the heating medium, which has been heated by the waste heat from the pressurizing device, through active heating. For example, the oil in a screw compressor that injects oil may have a temperature of 60°C to 100°C. For example, if the temperature is 60°C, but a temperature of 100°C is meaningful in the heat exchanger, especially in the heat transfer section of the heat exchanger, then, for example, the 60°C oil can be raised by 40K to 100°C and then used as appropriate in the heat exchanger.

[0047] In any embodiment using heated oil in a screw compressor that injects oil, a particular advantage is that the screw compressor can also be cooled simultaneously. This is obvious, however, only if the active additional heating of the heated oil does not involve inputting more energy than is released again in the heated region.

[0048] According to one embodiment, it is proposed to use at least two pressure vessels. In combined operation, at least one pressure vessel operates in a dry mode and the other operates in a regeneration mode. The pressure vessel operating in dry mode discharges dry compressed gas, and a portion of this compressed gas is diverted as a compressed gas fraction and supplied to the pressure vessel operating in regeneration mode, where it is used as regenerated gas.

[0049] In particular, since two pressure vessels are used that can essentially operate in alternating modes, one pressure vessel operates in dry mode and the other in regeneration mode. That is, the pressure vessel operating in dry mode supplies not only the required compressed gas, especially the required compressed air, but also the regeneration gas, i.e., regeneration air in the case of compressed air. The advantages described above regarding the use of the compressed gas fraction for regeneration can be fully realized in this way.

[0050] In other words, combined operation refers to a situation where the drying mode and regeneration mode function in parallel. However, there is also a situation where only the drying mode is present.

[0051] However, it should be noted that the drying mode and the regeneration mode do not necessarily have to be performed simultaneously and continuously. For example, the regeneration and regeneration modes may already be complete, but the drying mode may continue for a while. In this case, the drying mode produces exclusively dry compressed gas, which is used without being branched off for regeneration.

[0052] The drying mode is maintained, in particular, as long as the adsorbent material in the pressure vessel operating in drying mode can still absorb sufficient moisture. When the adsorbent material can no longer absorb sufficient moisture, and in some cases somewhat earlier, it is possible to switch the pressure vessel that was operating in drying mode to operating in regeneration mode. The pressure vessel that was operating in regeneration mode then operates in drying mode.

[0053] This principle is described using two pressure vessels that can function alternately. However, more pressure vessels may also be used. In particular, it is conceivable that multiple pressure vessels may always function in drying mode and multiple pressure vessels in regeneration mode. Whether to use two or more pressure vessels may also depend on the standard dimensions of the pressure vessels and the volume of compressed gas to be dried per unit time. When using two or more pressure vessels, it is conceivable that at least one functions in drying mode, at least one in regeneration mode, and at least one in standby mode.

[0054] In one embodiment, when switching from drying mode to regeneration mode, it is proposed that the flow of compressed gas from the drying inlet to the drying outlet is first blocked, then heating of the heating region is started, and after a predetermined heating time has elapsed since the start of heating, the regeneration gas is introduced into the container. As a result, the adsorbent material is heated in the heating region first, and only then is it possible for the regeneration gas to flow in. Therefore, the regeneration gas flows through the heating region which is heated from the beginning, and as a result, it is possible for the heating region to have a high water vapor absorption capacity from the beginning.

[0055] This prevents the regenerated gas from being wasted or not fully utilized initially. Furthermore, especially when combined with heating using waste heat, it is recognized that pre-heating the heating region before the regenerated gas passes through results in no energy loss, or only negligible energy loss. It is also recognized that since adsorbent materials can have high heat capacity, pre-heating essentially only stores heating energy, and that energy is not released without being utilized.

[0056] Similarly, it is recognized that sufficient time exists for regeneration during the operation of the adsorption device. In particular, sufficient time exists for regeneration in the advantageous alternating mode, which switches between drying mode and regeneration mode between at least two containers.

[0057] The predetermined heating time can be calculated based on the heat capacity of the adsorbent material in the heating region and the amount of heat supplied per unit time, i.e., thermal energy. In this case, the adsorption device is configured so that the supplied heat and the heat capacity of the adsorbent material in the heating region are adjusted to each other. The heating time ranges from 3 to 25 minutes.

[0058] In one embodiment, when switching from regeneration mode to drying mode, it is proposed that heating is first terminated, and after heating is complete, a predetermined cooling time is elapsed before compressed gas is introduced into the pressure vessel. In particular, it is stipulated that after heating is complete, the regeneration gas continues to flow through the pressure vessel for part or all of the cooling time.

[0059] By ending the heating in drying mode before the compressed gas is introduced for drying, cooling of the pressure vessel, particularly the adsorbent material in the heating region, as well as other elements in the heating region, is achieved. This prevents the compressed gas to be dried from being heated in the heating region, thereby increasing its water vapor absorption capacity and reducing the amount of moisture released. In other words, there is a risk that the compressed gas to be dried may not be sufficiently dried.

[0060] In particular, cooling can be promoted by allowing regenerated gas to continue flowing through the pressure vessel and therefore through the heated region after heating is complete. This allows the regenerated gas to cool the heated region. Ideally, this would occur throughout the entire cooling time, but for technical reasons, it may be possible to shorten this time somewhat.

[0061] In particular, in an alternating mode in which at least two pressure vessels can switch between drying and regeneration modes, the drying mode can be continued in at least one pressure vessel while the drying mode is prepared in the other pressure vessel. That is, the preparation is carried out by terminating the heating as described above while continuing the flow of regeneration gas. This regeneration gas continues to flow through the pressure vessels during the cooling time and can therefore continue to be supplied from the pressure vessel that is still operating in drying mode.

[0062] Furthermore, a pressure vessel operating in drying mode can switch to standby mode. In this standby mode, the flow of compressed gas to be dried through the pressure vessel is interrupted, especially if compressed gas is not required at that time. In this case, no other gases flow through the pressure vessel either. This standby mode is distinct from the cooling phase after heating is complete, before the actual drying mode is initiated by the inflow of compressed gas to be dried. In other words, during the cooling phase, it is specifically stipulated that regenerated gases flow through the pressure vessel.

[0063] The cooling time can be calculated based on the mass of regenerating gas flowing through the heated adsorbent relative to the mass of the adsorbent to be cooled. The adsorbent is also called a desiccant. For cooling, it is recognized that the ratio of the mass of regenerating gas to the mass of the heated adsorbent is in the range of 0.025 kg / kg to 0.22 kg / kg. In other words, the cooling time may be the time required for the corresponding mass of regenerating gas to flow through the compressed gas container.

[0064] Therefore, the cooling time also depends on the flow rate, that is, the mass of regenerated gas flowing through the pressure vessel per unit of time. This flow rate and the mass of the adsorbent material to be heated and then cooled are almost always coordinated with each other. As a result, a predetermined cooling time can be obtained, ranging from approximately 1 minute to 30 minutes.

[0065] In one embodiment, it is proposed that compressed air be dried as the compressed gas, and a portion of the dried compressed air be used as the regenerated gas. In this way, the regenerated air is used as the regenerated gas, and after passing through the drying section, the regenerated air flows out around the adsorption dryer.

[0066] Therefore, the proposed method can be used particularly for drying compressed air. It also has the advantage of being able to use ambient air that has been transformed into compressed air and then dried. A portion of the dried compressed air can be reused for regeneration and released back into the atmosphere without any problems. This eliminates the need to further dry the moisture-rich regenerated air.

[0067] In one embodiment, it is proposed that in the regeneration mode, the pressure inside the pressure vessel be reduced to the pressure outside the pressure vessel, particularly to atmospheric pressure or lower. This also reduces the pressure of the regeneration gas introduced into the pressure vessel. As a result, the regeneration gas can absorb more moisture, and therefore, the drying process of the adsorbent material, i.e., the regeneration of the adsorbent material, is improved compared to the case of higher pressure.

[0068] A special compressor may be provided to obtain this low pressure, which could also be called negative pressure. One way to achieve this is to introduce regenerated gas as regenerated air and discharge it from the pressure vessel to the surroundings using a compressor that reduces the pressure inside the pressure vessel, especially if the regenerated gas is air.

[0069] In one embodiment, it is proposed that dry compressed air flows out from a dry outlet and then through an auxiliary pressure vessel equipped with an adsorbent material, and that the auxiliary pressure vessel is not incorporated into the regeneration mode.

[0070] It is recognized that switching between drying mode and regeneration mode can affect the dryness of the compressed air, which is reflected in the pressure dew point of the dry compressed air. In particular, this pressure dew point may increase after switching from regeneration mode to drying mode. As a result, the compressed air will have a higher humidity than desired, which will allow it to release moisture more easily.

[0071] In other words, an auxiliary pressure vessel is provided for this purpose, and it has been proposed that moisture can be released into the adsorbent material at its high pressure dew point. However, this adsorbent material does not need to be dried again in another process. Rather, if the dry compressed air's pressure dew point drops again, it can reabsorb moisture from the adsorbent material in this additional pressure vessel. Therefore, the auxiliary pressure vessel does not switch between drying mode and regeneration mode.

[0072] The standard for determining the proportion of water vapor in compressed air is the pressure dew point, which is the temperature at which the partial pressure of water vapor in compressed air under operating pressure is exactly equal to the vapor pressure of water.

[0073] Although improvements have been achieved, in the proposed adsorption drying method using an adsorption dryer, the pressure dew point rises to a certain extent after switching the container from regeneration to drying.

[0074] Therefore, even in the proposed solution, the maximum pressure dew point may be higher than the mean pressure dew point. Furthermore, it is recognized that the maximum pressure dew point can be an important criterion, and solutions to lower the maximum pressure dew point have been found. In particular, this must be achieved without the significant increase in energy demand that is necessary when lowering the mean pressure dew point. At the very least, it must be achieved without increasing heating capacity, increasing the amount of regenerated air, or shortening the drying time.

[0075] As a solution, it is proposed that the dry compressed air, after flowing out from the dry outlet, flows through an auxiliary pressure vessel equipped with an adsorbent material. Thus, it is proposed that the dry compressed air passes through an adsorption buffer, which is a container filled with the dry material, i.e., an auxiliary pressure vessel.

[0076] If the residual moisture in the compressed air increases rapidly, the dry material will first absorb most of the added moisture, causing the pressure dew point at the outlet of the adsorption buffer to drop significantly compared to the inlet. If the compressed air has a lowered pressure dew point again in the subsequent process, the dry material will release the added moisture again. This causes the pressure dew point to rise slightly over a long period of time as it passes through the adsorption buffer.

[0077] Over the entire operating time of the adsorption buffer, the amount of water vapor in the compressed air does not decrease, but the maximum pressure dew point decreases significantly. This decrease is achieved with excellent energy efficiency because only the energy required to overcome the slight flow resistance of the adsorption buffer is needed for its operation.

[0078] In this invention, an adsorption dryer has also been proposed. Accordingly, an adsorption dryer for drying compressed gases, particularly compressed air, has been proposed, which has at least one pressure vessel equipped with an adsorbent material for adsorbing moisture from the compressed gas, and is configured to perform the following method. In this method, -In drying mode, in order to dry the compressed gas, the compressed gas flows through the pressure vessel along the adsorbent material from the drying inlet through the drying section to the drying outlet, and then flows out as dried compressed gas. -In the regeneration mode for regenerating the adsorbent material, the regeneration gas flows through the pressure vessel along the adsorbent material from the drying outlet through the drying section to the drying inlet, and during this process, moisture is removed from the adsorbent material. -In regeneration mode, partial heating is performed in the heating region within the pressure vessel. - The heating region is located only in a portion of the pressure vessel adjacent to the drying inlet.

[0079] In particular, it is proposed that the adsorption dryer be configured to perform a method according to any of the above-described aspects or embodiments. Preferably, the adsorption dryer is connected in correspondence so that the compressed gas and regenerated gas flow appropriately through the pressure vessel and are appropriately guided by appropriate connections. For control, appropriate control devices may be provided to start, control and terminate the drying mode and the regeneration mode, respectively. For heating, appropriate heating devices are provided. Furthermore, the adsorption dryer is configured to be connected to a pressurizing device, in particular a compressor, and a piping system for receiving and / or transferring the compressed gas.

[0080] The functions and advantages of such adsorption dryers are evident from the description of the method for drying compressed gases.

[0081] According to one embodiment, with respect to an adsorption type dryer, - The heating region is located in the portion of the drying section measured from the drying inlet to the drying outlet that is between 0% and 80%, preferably between 0% and 60%, and particularly between 0% and 50%. - It extends over at least 20%, preferably at least 30%, particularly at least 40%, preferably up to 70%, particularly up to 60%, of the dry section, and / or -A heat exchanger is provided for heating inside the pressure vessel. - The heat exchanger has a heat transfer portion that is placed in the heating region and surrounded by an adsorbent material. This has been proposed.

[0082] Therefore, a heating region is proposed that is effectively positioned in a location where the regeneration of the adsorbent material is improved.

[0083] According to one embodiment, with respect to an adsorption type dryer, -At least two pressure vessels are provided, and, - The adsorption dryer is capable of combined operation in which at least one pressure vessel functions in drying mode and the other pressure vessel functions in regeneration mode. - The pressure vessels are connected in such a way that a pressure vessel operating in dry mode discharges dry compressed gas, a portion of which is branched off as a compressed gas fraction and supplied to a pressure vessel operating in regeneration mode to be used as regenerated gas, and / or - An auxiliary pressure vessel equipped with adsorbent material is provided, and the auxiliary pressure vessel is connected to the remaining pressure vessel so as not to be incorporated into the regeneration mode. This is proposed.

[0084] Therefore, in particular, an adsorption dryer is provided in which multiple pressure vessels can switch between drying mode and regeneration mode. In this case, the pressure vessel operating in drying mode can release regenerating gas to the other pressure vessels operating in regeneration mode. For this purpose, the pressure vessels are connected to each other in corresponding ways, so that the corresponding compressed gas can flow from one pressure vessel to the other, and this can also be intentionally controlled by corresponding valves.

[0085] The auxiliary vessel may be positioned in front of the auxiliary pressure vessel with respect to the flow direction of the dry compressed gas, so that a portion of the dry compressed gas is guided from one pressure vessel to the other pressure vessel for use as regenerated gas. In particular, the auxiliary pressure vessel equipped with adsorbent material may be configured entirely passively, so that no active pressure changes, heating, or cooling occurs within the auxiliary pressure vessel.

[0086] For other aspects, please refer to the descriptions related to the drying method.

[0087] This invention also proposes a compressed gas system for supplying dry compressed gas. Therefore, - A pressurizing device for compressing gas into compressed gas, particularly a compressor, - An adsorption dryer comprising multiple pressure vessels filled with adsorbent material, wherein each pressure vessel is -Having a drying section for drying compressed gas, -The heating region extends only to a portion of the drying section, and a heat exchanger connected to the compressor is provided for heating the heating region in order to heat the heating region with waste heat from the compressor. Adsorption type dryer, A compressed gas system having the following has been proposed.

[0088] The compressed gas system preferably includes an adsorption dryer according to any of the embodiments described above. Therefore, the compressed gas system can obtain the advantages already described with respect to the adsorption dryer and drying method.

[0089] A particular advantage is the synergistic effect achieved by using the waste heat from the compressor for heating in the heating region of the adsorption dryer. This synergistic effect allows for the advantageous use of the waste heat from the compressor in the adsorption dryer.

[0090] The present invention will be described in detail below based on embodiments with reference to the accompanying drawings. [Brief explanation of the drawing]

[0091] [Figure 1a] This figure shows a compressed gas system with an adsorption dryer at different process steps. [Figure 1b] This figure shows a compressed gas system with an adsorption dryer at different process steps. [Figure 1c] This figure shows a compressed gas system with an adsorption dryer at different process steps. [Figure 1d] This figure shows a compressed gas system with an adsorption dryer at different process steps. [Figure 1e] This figure shows a compressed gas system with an adsorption dryer at different process steps. [Figure 2a] This figure shows a compressed gas system with an adsorption dryer in different process steps, according to another embodiment. [Figure 2b] This figure shows a compressed gas system with an adsorption dryer in different process steps, according to another embodiment. [Figure 2c] This figure shows a compressed gas system with an adsorption dryer in different process steps, according to another embodiment. [Figure 2d] This figure shows a compressed gas system with an adsorption dryer in different process steps, according to another embodiment. [Figure 2e] This figure shows a compressed gas system with an adsorption dryer in different process steps, according to another embodiment. [Figure 3a] This diagram shows the various heat transfer components of a heat exchanger. [Figure 3b] This diagram shows the various heat transfer components of a heat exchanger. [Figure 4a] This diagram shows the various heat transfer components of a heat exchanger. [Figure 4b] This diagram shows the various heat transfer components of a heat exchanger. [Modes for carrying out the invention]

[0092] Figure 1a is a schematic diagram of the compressed gas system 100. The compressed gas system 100 includes a compressor 1 and an adsorption dryer 102. The compressor 1, which may also be called a compressor, works in cooperation with an oil cooler 2, an oil separation container 3, and a compressed air cooler 4, which will be described in more detail below. The compressor 1 supplies compressed air to the adsorption device 102, which is located between two valves 5 and 6.

[0093] The adsorption dryer 102 has two pressure vessels 7 and 8, which can also be simply called vessels. In particular, these two pressure vessels 7 and 8 operate in alternating mode, so that one operates in drying mode and the other in regeneration mode. For this purpose, by the appropriate positioning of valves 5 and 6, compressed gas can be supplied to either of the two vessels 7 and 8 correspondingly for drying in drying mode.

[0094] Both containers 7 and 8 each have an upper portion 7a or 8a and a lower portion 7b or 8b. Both containers are filled with an adsorbent material, indicated as granular material.

[0095] The two containers 7 and 8 each have a drying inlet 103 or 104 and a drying outlet 105 or 106. In the illustrated embodiment, the drying inlets 103 and 104 are located on the lower side, and the drying outlets 105 and 106 are located on the upper side. Therefore, in drying mode, the compressed air to be dried flows from bottom to top, and the regenerated air flows from top to bottom.

[0096] The lower portion 7b or 8b of container 7 or 8 is heated by heater 16 or 17, respectively, and heater 16 or 17 forms a heating device. Therefore, when compressed air flows in from the drying inlet 103 or 104, it first passes through the heating region (which is off in drying mode), and then through the upper portion 7a or 8a. In regeneration mode, regeneration air flows from top to bottom, that is, it flows in from the drying outlet 105 or 106, first through the upper portion 7a or 8a, and then through the lower portion 7b or 8b, which can receive or form a heating region. In regeneration mode, heater 16 or 17 operates, respectively.

[0097] In drying mode, the dry compressed air flows out from either the drying outlet 105 or the drying outlet 106, depending on which of the two containers 7 and 8 is operating in drying mode, and mainly flows toward the valve 12, which may also be called the outlet valve, and from the valve 12 flows toward the dryer outlet 13, i.e., the outlet of the entire adsorption device 102. However, an auxiliary container with adsorption material may also be connected to compensate for fluctuations in the humidity level of the dry compressed air, which is provided according to one embodiment but is not shown here for simplicity.

[0098] Simultaneously, a portion of the dry compressed air is guided through throttle valves 10 and 11 in front of valve 12, and either or both of these throttle valves reduce the pressure of the dry compressed air, particularly to near ambient pressure. Which of the two throttle valves 10 and 11 reduces the pressure, and by how much, depends on which of the two vessels 7 and 8 is in drying mode and which is in regeneration mode. In either case, a portion of the dry compressed air is transferred through these two throttle valves 10 and 11, controlled by valve 9 located between them, from the vessel operating in drying mode to the vessel operating in regeneration mode.

[0099] Therefore, a container operating in regeneration mode receives regenerated air at a drying outlet 105 or 106, which passes through the respective container 7 or 8, in the process through a lower portion 7b or 8b that can be considered a heating region, and finally flows out from a drying inlet 103 or 104. From the drying inlet 103 or 104, the regenerated air can be discharged into the surroundings through a valve 18 or 19 and a downstreamly connected silencer 20 or 21.

[0100] One possible embodiment is simplified and shown in Figure 1a. Air is compressed by a compressor 1. At this time, oil cooled in an oil cooler 2 is injected into the compressor. The mixture of high-temperature compressed air and oil is separated in an oil separation container 3. The compressed air flows from the oil separation container to a compressed air cooler 4, where it is cooled.

[0101] Similarly, the oil temperature or temperature level can be increased by passing all or part of the oil through the compressor's oil heat exchanger 2 in a bypass manner and supplying it to the compressor block at a higher temperature.

[0102] In the depiction in Figure 1b, as an example, container 7 is used for drying and container 8 is being recycled. Valves 5, 9, and 19 are open, and valves 6 and 18 are closed. A three-way valve 12 connects container 7 to the dryer outlet 13.

[0103] Compressed air flows through valve 5 into container 7, where it is dried. Most of the moisture removed from the compressed air is absorbed by the desiccant in the lower part 7b of the container, where heater 16 is located. However, since heater 16 is not operating while container 7 is being used for drying, the drying material is not heated. Most of the dried compressed air flows through valve 12 to the dryer outlet 13. A small portion of the dried compressed air flows from container 7 to container 8 through valve 9. Throttle valves 10 and 11 reduce the pressure to approximately ambient pressure to generate as much regenerated air as possible. The reduced pressure air absorbs moisture from the drying material in container 8 and flows out of the container through valve 19 and silencer 21.

[0104] The heater 17 heats the drying material in the lower portion 8b of container 8. In this portion of the container, i.e., the lower portion 8b, most of the water was bound during the preceding drying process. Heating the drying material enhances the desorption of water, and heating the air allows more water vapor per unit mass of air to be transported from the container. This reduces the amount of regenerated air required to a much smaller amount than in the case of a low-temperature regenerative adsorption dryer. As a result, the methods shown in Figures 1a, 1b, and 1c are far more efficient than conventional methods. In Figure 1c, in the reverse mode, container 8 is used for drying and container 7 is being regenerated.

[0105] To further reduce the amount of regenerating air, the valve 9 can be kept closed until the dry material in region 8b is sufficiently heated by the heater 17 at the start of regeneration, thereby enabling efficient regeneration from the moment the regenerating air supply begins. This operation is shown in Figure 1d.

[0106] Compared to conventional heat-regenerating adsorption dryers, the amount of heat accumulated in the adsorbed material after regeneration is significantly less. This is because only a portion of the material is heated, and in addition, the use of reduced-pressure compressed air allows the regeneration process to be carried out at a lower temperature.

[0107] To further reduce accumulated heat, the heater 17 can be stopped during the final stage of regeneration, allowing the final stage of regeneration to be performed without heat supply. In this case, the mass of regenerated air used per unit mass of heated desiccant should be in the range of approximately 0.025 kg / kg to 0.22 kg / kg. Such an operation is shown in Figure 1e.

[0108] A particularly efficient embodiment that utilizes the waste heat from the compression process is shown in Figure 2a. This structure corresponds to the structure in Figure 1a, which has specific embodiments of heaters 16 and 17.

[0109] Heaters 16 and 17 can be permeated by opening valve 14 or 15, allowing hot oil from the compressor to flow through them. If neither heater is operating, valves 14 and 15 are closed, and valve 22 is opened instead.

[0110] Figure 2b shows the operation of using container 7 for drying and reusing container 8. Correspondingly, valve 15 is open, while valves 14 and 22 are closed.

[0111] Figure 2c shows the operation of using container 8 for drying and regenerating container 7. In this case, valve 14 is open, and valves 15 and 22 are closed.

[0112] Figure 2d shows the operation in which container 7 is used for drying and container 8 is preheated in preparation for the start of regeneration. Correspondingly, valve 15 is open here, while valve 9 remains closed.

[0113] Figure 2e shows an operation in which container 7 is used for drying and container 8 is not heated in the final stage of regeneration. Correspondingly, here valve 15 is closed and valve 9 remains open.

[0114] The embodiments shown in Figures 2a to 2e illustrate an advantageous and compact combination of compressor 1 and dryer. However, the dryer does not need to be directly connected to the compressor. In particular, multiple compressors can transport compressed air to one dryer, one compressor can transport compressed air to multiple dryers, or multiple compressors can transport compressed air to multiple dryers. A different heat transfer medium can be used instead of compressor oil to transfer heat output from the compressor to the dryer. To optimize the process, the heat transfer medium may be further heated, for example, by an electric heater, above the temperature level at which waste heat can be used.

[0115] Further aspects or supplementary explanations of the present invention are described below.

[0116] The following explanation assumes that the container is permeated from bottom to top during drying and from top to bottom during regeneration. However, other installation positions are also possible.

[0117] Therefore, the central aspects of the present invention are as follows: -A low-temperature regenerative adsorption dryer method is used. - In regeneration mode, heat is supplied by the heating device only to the lower part of the container.

[0118] Advantageously, existing waste heat, such as the heat contained in the oil of a screw compressor, can be used in the heating device. In water-cooled systems, hot water can also be used. Other heat sources that are readily available near the dryer can also be used. This method can also be implemented using electric heating.

[0119] The significant proportion of the heated lower portion of the container relative to the entire container is between approximately 20% and 70%.

[0120] Furthermore, direct heating offers the potential to supply more heat per unit volume of air than heating the air first and then the desiccant to desorb moisture. This reduces the amount of regenerated air required. The amount of regenerated air can be further reduced by first heating the drying material without permeation before the regenerated air is guided through the container to be regenerated.

[0121] Since dry air is used for regeneration, high temperatures are not required, unlike dryers that use heated ambient air for regeneration. This allows for the utilization of existing waste heat at low temperature levels.

[0122] In one embodiment, heated oil from an oil-injection screw compressor is used for heating during regeneration. This oil generally has a temperature of 60°C to 100°C.

[0123] Since the drying material is directly heated, regenerated air is only needed to transport the desorbed water vapor. Further reductions in the amount of regenerated air can be achieved by lowering the pressure during regeneration. The lower the regeneration pressure, the less compressed air needs to be depressurized to produce the required volumetric flow rate.

[0124] Figures 3a, 3b, 4a, and 4b show pressure vessels with different heating regions or heating regions with different arrangements. In the figures, the same reference numerals are used for elements or regions that are not necessarily identical in part, in order to facilitate comparison. In particular, all four figures show a pressure vessel 300 having an adsorbent layer 302, i.e., a layer of granular adsorbent material, and a heating region 304 having a heat exchanger 306, indicated by a symbol. The adsorbent layer 302, i.e., the region where the adsorbent layer 302 is located, is hatched with a dotted line. The heating region 304 is enclosed by a dashed line and further hatched with a dashed line. Thus, the heating region 304 is located within the region of the adsorbent layer 302, which is clearly indicated by the overlapping hatching. Similarly, the height h of the vessel is indicated in all four figures for reference of size ratios. Furthermore, a drying inlet 322 and a drying outlet 324 are indicated in all four figures.

[0125] It should be noted that the heat exchanger 306 is depicted symbolically in the figures. The heat exchanger 306 extends across the entire cross-section of the adsorbent layer 302. In particular, but not limited to, the pressure vessel and the corresponding adsorbent layer may have a cylindrical cross-section over which the heat exchanger 306 extends completely. Figures 3a, 3b, 4a, and 4b clearly illustrate the particularly different extents of the heat exchanger 306 in the flow direction, i.e., in the height h direction.

[0126] The size of the heating area 304 of the heat exchanger 306 is roughly equal to the installation space of the heat exchanger 306. Similarly, there may be adsorbents present here as well, which can be expressed as a synonym for adsorbent material. In other words, the heat exchanger 306 is surrounded by adsorbents.

[0127] Basically, there are embodiments of adsorption dryers that do not have a sieve bottom, a perforated plate, or the like at the lower end of the pressure vessel 300. In such embodiments, the adsorbent layer, which can be simply called a layer, is placed at the bottom of the container.

[0128] Figures 3a and 3b show such pressure vessels. In Figure 3a, due to the structure of the heat exchanger, the heating region 304 only begins at approximately 2% of the vessel height h and extends to approximately 30% of the vessel height h. The vessel height h is the length from the drying inlet to the drying outlet.

[0129] In Figure 3b, due to the structure of the heat exchanger, the heating region 304 begins at approximately 2% of the vessel height h and extends to approximately 60% of the vessel height h. Here, the drying section 326 in Figures 3a and 3b extends over the entire height h. Here, the drying section is represented only by an arrow indicating its length. In reality, the drying section extends, obviously, within the pressure vessel 300, i.e., within the adsorbent layer 302. The same applies to the drying section 426 in Figures 4a and 4b, which will be discussed below. Essentially, the region of the adsorbent layer 302 defines the drying sections 326 and 426.

[0130] Furthermore, there are embodiments of adsorption dryers that have a sieve bottom, a perforated plate, or the like in the lower region of the pressure vessel, which is called an offset bottom 308. This offset bottom has some space from the bottom of the pressure vessel and has holes small enough that process air can pass through but adsorbent particles cannot. In other words, the adsorbent layer is placed on the offset bottom 308, which may be, for example, a sieve bottom. As a result, the process air can flow downward into the space below the offset bottom 308 and then disperse before flowing upward through the layer. The advantage is that if condensate or liquid water flows into the bottom of the vessel with compressed air, and the condensate is not 100% separated downstream of the heat exchanger, the condensate will accumulate at the bottom of the vessel below the sieve bottom. In this case, the adsorbent is not present in the "liquid water".

[0131] Such embodiments with an offset bottom 308 are shown in Figures 4a and 4b. In these embodiments, the drying section 426 in Figures 4a and 4b does not extend over the entire height h.

[0132] Figure 4a shows a pressure vessel 300 with an offset bottom 308 which can be formed as a sieve bottom or a perforated plate, located at approximately 3% of the vessel height h. The heating region 304 begins at approximately 5% of the vessel height h and extends to approximately 30% of the vessel height h, due to the structure of the heat exchanger.

[0133] The layer can be pressed down from above, for example, by a compression spring 312 using a perforated plate 310, so that even if the direction of flow of the compressed gas changes, i.e., if the flow reverses, the particulate material will not move or be blown up. This prevents mechanical wear of the particulate material. In this case, the particulate material extends to approximately 92% of the height h of the container.

[0134] Figure 4b shows a pressure vessel 300 having an offset bottom 308 which can be formed as a sieve bottom or a perforated plate, located at approximately 3% of the vessel height h. Due to the structure of the heat exchanger, the heating region 304 only begins at approximately 5% of the vessel height h and extends to approximately 60% of the vessel height h.

[0135] Here too, the layer can be pressed down from above, for example, by a compression spring 312 using a perforated plate 310, so that even if the direction of flow of the compressed gas changes, that is, if the flow reverses, the particulate material will not move or be blown up. This prevents mechanical wear of the particulate material. In this case, the particulate material extends to about 92% of the height h of the container. [Explanation of Symbols]

[0136] 1 Compressor 2. Oil cooler 3. Oil separation container 4. Compressed air cooler 5, 6, 9, 12, 14, 15, 18, 19, 22 valves 7, 8 Pressure vessels 7a, 8a upper part 7b, 8b lower part 10, 11 Throttle valve 13 Dryer outlet 16, 17 Heater 20, 21 Silencer 100 Compressed Gas Systems 102 Adsorption dryer 103, 104 Drying entrance 105, 106 Drying outlet 300 pressure vessels 302 Adsorbent layer 304 Heating area 306 Heat exchanger 308 Offset bottom 310 Perforated plate 312 Compression spring 322 Drying Inlet 324 Drying outlet 326, 426 Dry section h height of the container

Claims

1. A method for drying compressed gas using an adsorption dryer, wherein the adsorption dryer has at least one pressure vessel equipped with an adsorbent material for adsorbing moisture from the compressed gas. In the drying mode for drying the compressed gas, the compressed gas flows through the pressure vessel along the adsorbent material from the drying inlet through the drying section to the drying outlet, and flows out as dried compressed gas. In the regeneration mode for regenerating the adsorbent material, the regeneration gas flows through the pressure vessel along the adsorbent material from the drying outlet through the drying section to the drying inlet, and in this process, moisture is removed from the adsorbent material, and In the regeneration mode, partial heating is performed in the heating region within the pressure vessel. The heating region is located only in a portion of the pressure vessel adjacent to the drying inlet.

2. The heating region is located in the portion of the drying section measured from the drying inlet to the drying outlet that covers 0% to 80%, and / or The heating region extends over at least 20% of the drying section. The method according to claim 1, characterized in that, outside the heating region, heating is not performed, or heating is performed with an energy input per unit volume reduced to less than 30% compared to the heating region.

3. The compressed gas fraction, which is part of the dried compressed gas, is used as regenerated gas. The compressed gas fraction at the drying outlet is introduced into the pressure vessel, and The method according to claim 1, characterized in that the compressed gas fraction is depressurized when it is introduced into the pressure vessel or before it is introduced.

4. The heating inside the pressure vessel is performed using a heat exchanger. The method according to claim 1, characterized in that the heat transfer portion of the heat exchanger is surrounded by the adsorbent material in order to release heat to the adsorbent material.

5. The compressed gas is generated by a pressurizing device, and The waste heat from the pressurizing device is used to heat the heating region during regeneration. The method according to claim 1, characterized in that heated oil from an oil-injection screw compressor is used to heat the heating region during regeneration.

6. The heating of the aforementioned heating region Waste heat from the pressurizing device, This is done using active heating from an energy source. The method according to claim 1, characterized in that the temperature of the heating medium heated by waste heat is further raised to a predetermined temperature by active heating.

7. At least two of the aforementioned pressure vessels are used, In combined operation, at least one of the pressure vessels operates in drying mode, the other pressure vessel operates in regeneration mode, and The method according to claim 1, characterized in that the pressure vessel operating in drying mode discharges dry compressed gas, a portion of the dry compressed gas is separated as a compressed gas fraction and supplied to the pressure vessel operating in regeneration mode, and used as the regenerated gas.

8. When switching from the drying mode to the regeneration mode, First, the flow of the compressed gas from the drying inlet to the drying outlet is blocked, Next, heating of the heating region is started, and The method according to claim 1, characterized in that a predetermined heating time elapses after the start of heating until the regenerated gas is introduced into the pressure vessel.

9. When switching from the regeneration mode to the drying mode, First, finish heating, After heating is complete, a predetermined cooling time elapses before the compressed gas is introduced into the pressure vessel. The method according to claim 1, characterized in that, after the completion of heating, the regenerated gas continues to flow through the pressure vessel for part or all of the cooling time.

10. The compressed gas is dried compressed air. A portion of the dry compressed air is used as the regenerated gas, thereby, The method according to claim 1, characterized in that regenerated air is used as the regenerated gas, and the regenerated air flows out to the vicinity of the adsorption dryer after passing through the drying section.

11. The method according to claim 1, characterized in that, in the regeneration mode, the pressure inside the pressure vessel becomes lower than the pressure outside the pressure vessel.

12. The method according to claim 1, characterized in that dry compressed air flows out from the drying outlet and then through an auxiliary pressure vessel equipped with an adsorbent material, and the auxiliary pressure vessel is not incorporated into the regeneration mode.

13. An adsorption dryer for drying compressed gas, comprising at least one pressure vessel equipped with an adsorbent material for adsorbing moisture from the compressed gas, and prepared to carry out a method, wherein the method involves, In the drying mode for drying the compressed gas, the compressed gas flows through the pressure vessel along the adsorbent material from the drying inlet through the drying section to the drying outlet, and flows out as dried compressed gas. In the regeneration mode for regenerating the adsorbent material, the regeneration gas flows through the pressure vessel along the adsorbent material from the drying outlet through the drying section to the drying inlet, and in this process, moisture is removed from the adsorbent material, and In the regeneration mode, partial heating is performed in the heating region within the pressure vessel, and The heating region is located only in a portion of the pressure vessel adjacent to the drying inlet, and / or An adsorption dryer configured to carry out the method described in claim 1.

14. The heating region is located in the portion of the drying section measured from the drying inlet to the drying outlet that covers 0% to 80% of the drying section. The heating region extends over at least 20% of the drying section, and / or A heat exchanger is provided for heating inside the pressure vessel. The adsorption type dryer according to claim 13, characterized in that the heat exchanger has a heat transfer portion arranged in the heating region, and the heat transfer portion is surrounded by the adsorption material.

15. At least two pressure vessels are provided. The adsorption dryer is configured to perform a combined operation in which at least one of the pressure vessels functions in drying mode and the other pressure vessel functions in regeneration mode. The pressure vessels are connected to each other in a cooperative manner, so that the pressure vessel operating in the drying mode releases dry compressed gas, a portion of the dry compressed gas is branched off as a compressed gas fraction and supplied to the pressure vessel operating in the regeneration mode to be used as regenerated gas, and / or The adsorption dryer according to claim 13, characterized in that an auxiliary pressure vessel equipped with an adsorption material is provided, and the auxiliary pressure vessel is connected to other pressure vessels so as not to be incorporated into the regeneration mode.

16. A compressor for compressing gas into compressed gas, An adsorption dryer comprising a plurality of pressure vessels filled with adsorption material, wherein each of the pressure vessels is It has a drying section for drying compressed gas, The heating region extends only to a portion of the drying section, and a heat exchanger connected to the compressor is provided for heating the heating region using the waste heat from the compressor. An adsorption dryer according to any one of claims 13 to 15 is used. Adsorption dryer and A compressed gas system for supplying dry compressed gas, having the following features.

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