Circulating air cooler, air blast heat regeneration dryer and control method thereof

Abstract

The present application relates to a circulating air cooler, a blast hot regeneration dryer and a control method thereof, the circulating air cooler comprising a shell, a partition plate and a heat exchange part, the partition plate divides the shell into an air suction heat exchange cavity and an air outlet heat exchange cavity, the heat exchange part divides each cavity into high and low temperature sides, and a position adjusting mechanism is arranged at the partition plate to change the contact area of the two cavities and the heat exchange part. In the circulating cooling stage of the dryer, the adsorption tower, the air suction heat exchange cavity, the air blower and the air outlet heat exchange cavity form a circulating loop, and the high-temperature gas passes through the two cavities for double cooling before and after being boosted by the air blower. The control method is based on the circulating cooling time or the temperature of the high-temperature side of the air suction heat exchange cavity, and the position adjusting mechanism is used to dynamically adjust the heat exchange area ratio of the two cavities, so that the heat exchange capacity is adapted to the load change. The present application can eliminate the influence of the work temperature rise of the air blower, improve the cooling speed and efficiency of the adsorption tower, shorten the cooling time, reduce the energy consumption, and has a compact structure and high integration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressed gas drying and heat exchange energy saving, in particular to a circulating air cooler, a blast heat regeneration dryer and a control method thereof. BACKGROUND

[0002] The blast heat regeneration dryer is a compressed gas drying device based on the principle of variable temperature and variable pressure adsorption. The continuous drying is realized by alternately performing the adsorption and regeneration processes in the double adsorption towers. When one tower adsorbs the moisture in the compressed gas, the other tower sequentially experiences the stages of pressure relief, heating regeneration, circulating cooling and standby charging. In the circulating cooling stage, the temperature of the adsorption tower needs to be reduced from 180-200℃ to 35-40℃ to restore the adsorption capacity.

[0003] In the prior art, such as the zero-gas-consumption blast regeneration dryer disclosed in CN106390697A, the circulating cooling stage only uses the air blower to extract the gas, which is cooled by a single cooler (suction cooling) and then blown back to the adsorption tower. However, when the air blower is working, the mechanical energy is converted into the internal energy of the air, resulting in a temperature rise of 8-15℃ of the gas. This temperature rise is not effectively eliminated, which prolongs the cooling time of the adsorption tower by 25-40 minutes and increases the comprehensive power consumption by 20-30%. Moreover, the existing cooling structure cannot dynamically adjust the heat exchange capacity according to the load change in the cooling stage, and there is a problem of insufficient utilization of low-temperature medium.

[0004] Therefore, the prior art cannot balance the three aspects of "fast cooling, low energy consumption and compact structure", and there is an urgent need for a circulating air cooler, a blast heat regeneration dryer and a control method thereof to solve the problems existing in the prior art. SUMMARY

[0005] The present application aims to solve the problems that the existing blast heat regeneration dryer cannot dynamically match the changing heat exchange load in the cooling process, resulting in the inability to eliminate the temperature rise of the air blower and the low utilization rate of the cooling area. A circulating air cooler, a blast heat regeneration dryer and a control method thereof are provided. The shell is divided into an air suction heat exchange cavity and an air outlet heat exchange cavity by a partition. The contact area of the two cavities and the heat exchange part is dynamically adjusted by a position adjusting mechanism. The high-temperature gas discharged from the adsorption tower is cooled twice by the two cavities before and after the air blower is pressurized. Combined with the heat exchange area adjustment method based on time or temperature, efficient cooling is realized.

[0006] To achieve the above application purposes, in the first aspect, the present application adopts the following technical scheme: a circulating air cooler comprises:

[0007] a shell;

[0008] a partition that divides the shell into an air suction heat exchange cavity and an air outlet heat exchange cavity;

[0009] The heat exchange part is arranged in the shell and separates the air suction heat exchange cavity into an air suction high-temperature side and an air suction low-temperature side and separates the air outlet heat exchange cavity into an air outlet high-temperature side and an air outlet low-temperature side.

[0010] The position adjusting mechanism is coupled with the partition plate or the heat exchange part and is used for changing the effective heat exchange area of the air suction heat exchange cavity and the air outlet heat exchange cavity with the heat exchange part.

[0011] The air suction high-temperature side, the air suction low-temperature side, the air outlet high-temperature side and the air outlet low-temperature side are each provided with a gas interface in communication with the outside, and the heat exchange part is provided with a medium interface for the flow of low-temperature medium.

[0012] The circulating air cooler is configured to, in the circulating cooling stage of the air blast heat regeneration dryer, make the high-temperature gas from the adsorption tower flow through the air suction heat exchange cavity, the air blower and the air outlet heat exchange cavity in sequence and then return to the adsorption tower, and adjust the effective heat exchange area in real time through the position adjusting mechanism to match the cooling load changed in the circulating cooling stage.

[0013] Further, the position adjusting mechanism includes a linear motor module or a linear guide rail, and the partition plate reciprocates along a direction perpendicular to the heat exchange part under the drive of the linear motor module or the linear guide rail.

[0014] Further, the heat exchange part is a plate-fin heat exchanger, and the low-temperature medium is selected from water, an alcohol aqueous solution, a hydrofluorocarbon refrigerant or a hydrofluoroolefin refrigerant.

[0015] Further, the plate-fin heat exchanger is a cross-flow plate-fin heat exchanger, the air-side fin pitch of which is 2.5-4 mm, and the fin height is 3-5 mm.

[0016] In a second aspect, an air blast heat regeneration dryer includes an air blower, a first adsorption tower and a second adsorption tower which are cyclically switched to work, when any one of the towers is in an adsorption stage, the other tower sequentially completes a pressure relief stage, a heating regeneration stage, a circulating cooling stage and a pressure charging standby stage, and the air blast heat regeneration dryer further includes the circulating air cooler as described above, the air outlet heat exchange cavity of the circulating air cooler is arranged between the air exhaust end of the air blower and the cold-blowing air inlet of the adsorption tower, and the air suction heat exchange cavity of the circulating air cooler is arranged between the cold-blowing air exhaust of the adsorption tower and the air suction end of the air blower.

[0017] When any one of the adsorption towers is in the circulating cooling stage, the adsorption tower, the air suction heat exchange cavity, the air blower and the air outlet heat exchange cavity form a closed circulating air flow loop.

[0018] In a third aspect, a control method of the air blast heat regeneration dryer as described above includes:

[0019] Obtaining state information reflecting the progress of the circulating cooling stage;

[0020] According to the state information, determining a target area ratio of the air suction heat exchange cavity and the air outlet heat exchange cavity;

[0021] The position adjusting mechanism is driven to make the effective heat exchange area ratio of the air suction heat exchange cavity and the air outlet heat exchange cavity to the heat exchange part reach a target area ratio.

[0022] The state information is at least one of the time that the cycle cooling phase has been performed or the gas temperature of the high-temperature side of the air suction heat exchange cavity.

[0023] Further, the state information reflecting the progress of the cycle cooling phase is obtained, including:

[0024] The minimum value R1 of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, the maximum value R2 of the heat exchange area ratio, and the starting action time t0 of the partition are obtained.

[0025] According to the state information, the target area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity is determined, including:

[0026] When any adsorption tower is in the cycle cooling phase and the time of entering the phase is less than t0, the heat exchange area S1 of the air suction heat exchange cavity is determined according to a first preset formula.

[0027] When any adsorption tower is in the cycle cooling phase and the time of entering the phase is not less than t0, the heat exchange area S1 of the air suction heat exchange cavity is determined according to a second preset formula, wherein the second preset formula is based on R1, R2, the time t that the cycle cooling phase has been performed, and the total time setting value t R of the cycle cooling phase.

[0028] Further, the first preset formula is:

[0029]

[0030] S is the total heat exchange area of the cycle air cooler;

[0031] The second preset formula is:

[0032]

[0033] Wherein, t is the time that the cycle cooling phase has been performed; t R is the total time setting value of the cycle cooling phase.

[0034] Further, based on the high-temperature side temperature T FH of the air suction heat exchange cavity, the low-temperature side temperature T FL of the air suction heat exchange cavity, the high-temperature side temperature T DH of the air outlet heat exchange cavity, the low-temperature side temperature T DL of the air outlet heat exchange cavity, the outlet temperature T RO of the low-temperature medium, and the inlet temperature T RIA third preset formula is derived, and the third preset formula is used to calculate the optimal contact area ratio of the air suction heat exchange cavity area S1 and the air outlet heat exchange cavity area S2:

[0035]

[0036] When R is less than or equal to R1, the partition position is adjusted to make the heat exchange area ratio of the two be R1;

[0037] When R is greater than R1 and less than R2, the partition position is adjusted to make the heat exchange area ratio of the two be R;

[0038] When R is greater than or equal to R2, the partition position is adjusted to make the heat exchange area ratio of the two be R2, wherein R1 is the minimum value of the heat exchange area ratio, and R2 is the maximum value of the heat exchange area ratio.

[0039] The optimal contact area ratio is taken as the target area ratio.

[0040] Further, R1 is in the range of 0.3-0.45, and R2 is in the range of 4-6.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] 1. Significantly improving cooling efficiency: through double cooling (air suction + air outlet), the temperature rise of the air blower is fully eliminated, the cooling speed of the adsorption bed is improved, the single-tower cooling time is shortened by 30.4% compared with one-stage cooling, and is shortened by 19.6% compared with fixed two-stage cooling;

[0043] 2. Reducing energy consumption: the energy consumption of single-tower cooling is reduced by 26.6% compared with one-stage cooling, and is reduced by 18.2% compared with fixed two-stage cooling;

[0044] 3. Dynamically adapting load: through the position adjusting mechanism, the heat exchange area ratio of the two cavities is adjusted in real time to adapt to the load change (the load of the air suction cavity decreases, and the load of the air outlet cavity is constant) in the cooling stage, and the utilization rate of the low-temperature medium is improved;

[0045] 4. Compact structure: integrating the air suction and air outlet cooling functions, the equipment occupies less space, and the system integration degree is improved. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 is a structural schematic diagram of a circulating air cooler of the present application;

[0047] Figure 2 is a structural schematic diagram of a blast air heat regeneration dryer of the present application;

[0048] Figure 3 is Figure 1 the sectional view of A-A of

[0049] In the diagram, PA is the partition; CS is the shell; HE is the heat exchange section; FH is the high-temperature side of the suction heat exchange chamber; FL is the low-temperature side of the suction heat exchange chamber; DH is the high-temperature side of the outlet heat exchange chamber; DL is the low-temperature side of the outlet heat exchange chamber; A1 is the high-temperature side interface of the suction; A2 is the low-temperature side interface of the suction; B1 is the high-temperature side interface of the outlet; B2 is the low-temperature side interface of the outlet; C1 is the low-temperature medium inlet of the heat exchange section; C2 is the low-temperature medium outlet of the heat exchange section; LM1-LM8 are the position adjustment mechanisms.

[0050] T1, First Adsorption Tower; T2, Second Adsorption Tower; RB, Blower; EH, Heater; AF, Intake Filter; HR, Circulating Air Cooler; MF1, T1 Tower Silencer; MF2, T2 Tower Silencer; V1, T1 Tower Adsorption Inlet Valve; V2, T2 Tower Adsorption Inlet Valve; V3, T1 Tower Regeneration Exhaust Valve; V4, T2 Tower Regeneration Exhaust Valve; V5, Regeneration Gas Vent Valve; V6, Blower Outlet Valve; V7, Circulating Cold Blowing Inlet Valve; V8, T1 Tower Regeneration Inlet Valve; V9, T2 Tower Regeneration Inlet Valve; V10, T1 Tower Pressure Relief Valve; V11, T1 Tower Pressurization Valve; V12, T2 Tower Pressurization Valve; V13, T2 Tower Pressure Relief Valve; V14, T1 Tower Finished Gas Exhaust Valve; V15, T2 Tower Finished Gas Exhaust Valve. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0052] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0053] Example 1

[0054] like Figure 1 and Figure 3 As shown, this circulating air cooler HR includes a shell CS, a baffle PA and a heat exchange section HE. It is used in a blower hot regeneration dryer and has both blower intake cooling and exhaust cooling functions.

[0055] In the embodiment, the partition PA divides the shell CS into two independent heat exchange chambers, namely the air suction heat exchange chamber and the air outlet heat exchange chamber. The heat exchange part HE further divides the air suction heat exchange chamber into the air suction high-temperature side FH and the air suction low-temperature side FL, and divides the air outlet heat exchange chamber into the air outlet high-temperature side DH and the air outlet low-temperature side DL.

[0056] Specifically, the air suction high-temperature side FH is provided with an interface A1 communicating with the outside, and the air suction low-temperature side FL is provided with an interface A2; the air outlet high-temperature side DH is provided with an interface B1, and the air outlet low-temperature side DL is provided with an interface B2, which are used to connect with other components (such as the adsorption tower and the air blower) of the air-blast heat regeneration dryer to form an air flow channel.

[0057] Specifically, the heat exchange part HE is provided with a low-temperature medium inlet C1 and a low-temperature medium outlet C2, through which the low-temperature medium (such as water, refrigerant, etc.) enters and flows out, and exchanges heat with the high-temperature gas flowing through the air suction heat exchange chamber and the air outlet heat exchange chamber.

[0058] Specifically, the connection part of the partition PA and the shell CS or the heat exchange part HE is provided with a position adjusting mechanism (such as a linear motor module or a linear guide rail, such as LM1-LM8 in Figure 1 The number of the position adjusting mechanism does not constitute a limitation to the protection scope of the present application), through which the contact area of the air suction heat exchange chamber, the air outlet heat exchange chamber and the heat exchange part HE can be changed, so as to dynamically adjust the heat exchange capacity of the two chambers and adapt to the load change in the circulating cooling stage. For example, the linear motor module usually includes a slider, a limit switch, a guide rail, a motor fixing seat and a motor connecting flange. The guide rail is fixed to the inner wall of the shell CS and / or the outer side of the heat exchange part HE, the slider is fixedly connected with the partition PA, and drives the partition PA to move perpendicularly to the heat exchange part HE, so as to adjust the contact area of the chamber (FH, FL, DH, DL) and the heat exchange part.

[0059] In the embodiment, the heat exchange part HE is a plate-fin heat exchanger (preferably a cross-flow plate-fin heat exchanger), the low-temperature medium is water, an alcohol substance aqueous solution, a hydrofluorocarbon refrigerant or a hydrofluoroolefin refrigerant, etc., the air side fin pitch of the heat exchanger is 2.5-4 mm, and the fin height is 3-5 mm. The position adjusting mechanism adopts a linear motor module or a combination of a linear guide rail and a linear motor. As long as the rotation of the motor is converted into linear motion, the purpose is to adjust the position of the heat exchange part or the partition, so that the effective heat exchange area of the air suction heat exchange chamber and the air outlet heat exchange chamber with the heat exchange part changes. Since the plate-fin heat exchanger, the linear motor module or the combination of the linear guide rail and the linear motor are all prior art and mature products, their structure and principle will not be described here. The present application also does not exclude other products or structures that can achieve the same function. Any change as long as the function is similar should be within the protection scope of the present application.

[0060] Example 2

[0061] Based on the same concept, the present invention integrates the circulating air cooler HR of Example 1 into a zero-air-consumption blower regeneration dryer.

[0062] like Figure 2 As shown, during the circulating cooling process, the high-temperature gas from the first adsorption tower T1 (or the second adsorption tower T2) enters the cooler through the high-temperature side port A1 of the high-temperature side FH of the suction heat exchange chamber. After being cooled by heat exchange with the heat exchange section HE, it is discharged through the low-temperature side port A2 of the low-temperature side FL of the suction heat exchange chamber. After being pressurized by the blower RB, it enters the cooler through the high-temperature side port B1 of the high-temperature side DH of the outlet heat exchange chamber. After being cooled by heat exchange with the heat exchange section HE again, it is discharged through the low-temperature side port B2 of the outlet heat exchange chamber DL and re-enters the first adsorption tower T1 (or the second adsorption tower T2).

[0063] The process flow of this forced-air hot regeneration dryer is as follows:

[0064] Moist compressed gas from upstream enters the blower-heated regeneration dryer through the inlet. At this time, one of the adsorption towers (such as the first adsorption tower T1) is in an adsorption state. The moist compressed gas enters the first adsorption tower T1 through the adsorption inlet valve V1 of tower T1. The moisture in the compressed gas is adsorbed on the surface of the adsorbent in the first adsorption tower T1 through the interaction force with the surface of the adsorbent. The dried compressed air reaches the outlet through the finished gas exhaust valve V14 of tower T1 and enters the downstream gas consumption unit.

[0065] When one adsorption tower (such as the first adsorption tower T1) is in the adsorption state, the other adsorption tower (such as the second adsorption tower T2) is in the regeneration state. The two towers cycle and switch continuously to dry the compressed air and continuously output clean compressed air.

[0066] The adsorbent regeneration process of the blower hot regeneration dryer consists of four stages: depressurization, heating regeneration, cold blowing and cooling, and pressurization (standby).

[0067] Heating and regeneration stage: Ambient gas passes through intake filter AF, is pressurized by blower RB, and enters heater EH through blower outlet valve V6; ambient gas heated by heater EH enters adsorption tower in regeneration state (such as second adsorption tower T2), causing adsorbate adsorbed on the surface of adsorbent in second adsorption tower T2 to detach, restoring adsorption performance, and gas carrying moisture is discharged to the environment through T2 tower regeneration exhaust valve V4 and regeneration gas vent valve V5 in sequence.

[0068] Cold blow cooling stage: the blower RB, the adsorption tower (such as the second adsorption tower T2) in the regeneration state and the circulating air cooler HR form a closed circulation flow path; the RB provides power to enable the air in the system to continuously carry heat from the adsorbent in the second adsorption tower T2 to flow through the HR, sequentially pass through the air suction heat exchange cavity and the air outlet heat exchange cavity of the HR to exchange heat with the low-temperature medium to gradually reduce the temperature of the second adsorption tower T2 to a suitable adsorption temperature.

[0069] In the present embodiment, the double-tower circulation step sequence table of the blast heat regeneration dryer of the present application is shown in Table 1 as follows:

[0070] Table 1

[0071]

[0072] The working state and method of each step of the blast heat regeneration dryer are as follows (taking the adsorption of the first adsorption tower T1 and the regeneration of the second adsorption tower T2 as an example):

[0073] Step one, adsorption of the first adsorption tower T1 and pressure relief of the second adsorption tower T2:

[0074] The humid compressed gas enters the dryer through the gas inlet INLET, enters the first adsorption tower T1 through the T1 tower adsorption inlet valve V1, and the water in the compressed gas is adsorbed by the adsorbent in the tower. The dry compressed gas reaches the gas outlet OUTLET through the T1 tower finished gas exhaust valve V14.

[0075] At the same time, the compressed gas in the second adsorption tower T2 is discharged to the environment through the T2 tower pressure relief valve V13 and the T2 tower muffler MF2.

[0076] Step two, adsorption of the first adsorption tower T1 and heating regeneration of the second adsorption tower T2:

[0077] According to the adsorption flow path of step one, the humid compressed gas is continuously adsorbed and dried by the first adsorption tower T1.

[0078] At the same time, the ambient air passes through the air filter AF, is pressurized by the blower RB, enters the heater EH through the blower outlet valve V6, and is heated by the heater EH. The ambient air then enters the second adsorption tower T2 to heat and dehydrate the adsorbent in the tower, and carries the water separated from the adsorption bed to be discharged to the environment through the T2 tower regeneration exhaust valve V4 and the regeneration gas vent valve V5.

[0079] Step three, adsorption of the first adsorption tower T1 and cold blow cooling of the second adsorption tower T2:

[0080] According to the adsorption flow path of step one, the humid compressed gas is continuously adsorbed and dried by the first adsorption tower T1.

[0081] At the same time, the normal pressure air from the second adsorption tower T2 enters the second adsorption tower T2 through the T2 tower regeneration air inlet valve V9, the circulating cold air inlet valve V7, is cooled in the circulating air cooler HR air inlet heat exchange cavity, is pressurized by the air blower RB, is cooled again in the circulating air cooler HR air outlet heat exchange cavity, and then enters the second adsorption tower T2 from the bottom through the air blower air outlet valve V6 and the T2 tower regeneration air outlet valve V4, so as to form a closed circulation flow path.

[0082] During the circulation process, the heat of the adsorption bed in the second adsorption tower T2 is continuously taken out and discharged from the system by the circulating air cooler HR, and the temperature of the adsorption bed is gradually reduced.

[0083] Step four, adsorption of the first adsorption tower T1 and pressure equalization of the second adsorption tower T2:

[0084] According to the adsorption flow path of step one, the adsorption and drying treatment of the humid compressed gas is continuously carried out by the first adsorption tower T1.

[0085] At the same time, the air blower stops running, and the T2 tower regeneration air inlet valve V9 and the T2 tower regeneration air outlet valve V4 are closed. Part of the finished product gas from the dryer outlet OUTLET enters the second adsorption tower T2 through the T2 tower pressure charging valve V12, and the pressure in the tower is gradually increased to the same as the pressure in the first adsorption tower T1, so as to prepare for the next adsorption cycle.

[0086] After the above steps one to four are completed, the two towers are switched, and the second adsorption tower T2 carries out the adsorption and drying treatment of the humid compressed gas, and the first adsorption tower T1 carries out the pressure relief, heating regeneration, cold blow cooling and pressure equalization process in turn.

[0087] Among them, the operation process and valve state table of the air blast heat regeneration dryer of the present application are as shown in Table 2:

[0088] Table 2

[0089]

[0090] Example 3

[0091] Based on the same concept, the present embodiment provides a control method in the circulating cooling process of the air blast regeneration dryer of example 2. Since in the circulating cooling stage of the air blast regeneration dryer, the air is formed between the adsorption tower in the regeneration state (such as the second adsorption tower T2) and the circulating air cooler HR to form a closed circulation flow path, the heat in the adsorption tower is continuously taken away. The specific process is as follows:

[0092] The second adsorption tower T2 in the regeneration state is at a temperature of 180-200°C at the beginning of the cycle cooling stage, and gradually decreases to 35-40°C as the cycle proceeds; the low-temperature medium (such as 32°C cooling water) flowing in the cycle air cooler HR enters through the low-temperature medium inlet C1 of the heat exchange part and flows out from the low-temperature medium outlet C2 of the heat exchange part, and as a heat carrier, takes the heat of the adsorption tower out of the system.

[0093] The air circulation path is as follows: the high-temperature air in the second adsorption tower T2 first enters the suction heat exchange cavity high-temperature side FH of the cycle air cooler HR through the cold-blow exhaust port, exchanges heat with the low-temperature medium in the heat exchange part HE, and is discharged from the suction heat exchange cavity low-temperature side FL (the FL outlet air temperature is designed to be 40°C); the cooled air enters the booster RB for pressure increase, and then enters the outlet heat exchange cavity high-temperature side DH of the cycle air cooler HR, exchanges heat with the low-temperature medium again, and is discharged from the outlet heat exchange cavity low-temperature side DL, and finally returns to the second adsorption tower T2 through the cold-blow inlet, completing one cycle.

[0094] In this process, the load of the suction heat exchange cavity gradually decreases as the adsorption tower cools down: at the beginning, the inlet air temperature of the suction heat exchange cavity high-temperature side FH is 180-200°C, which needs to be greatly cooled by heat exchange to 40°C at the suction heat exchange cavity low-temperature side FL; at the end, the inlet air temperature of the suction heat exchange cavity high-temperature side FH decreases to 40-45°C, and only a small amount of cooling is needed to maintain the 40°C at the suction heat exchange cavity low-temperature side FL. The core role of the outlet heat exchange cavity is to eliminate the temperature rise of the gas generated by the work of the booster RB (because mechanical energy is converted into internal energy, the temperature of the air after passing through the RB will rise), and to ensure that the temperature of the air entering the second adsorption tower T2 is low enough, so the heat exchange load is constant, and the temperature of the air at the outlet heat exchange cavity high-temperature side DH is continuously cooled to the appropriate temperature at the outlet heat exchange cavity low-temperature side DL, ensuring efficient cooling of the adsorption tower.

[0095] In the process of the cycle cooling of the air-blowing regeneration dryer, the theoretical temperatures at each time point are as shown in Table 3:

[0096] Table 3

[0097]

[0098] As can be seen from the above table, in the cycle cooling process of the adsorption tower, as the temperature of the adsorption bed gradually decreases, the load of the suction heat exchange cavity will gradually decrease, while the load of the outlet heat exchange cavity is a fixed value. Therefore, at the initial stage of the cycle cold-blowing, the heat exchange area of the cycle air cooler HR needs to be large, otherwise the expected cooling effect cannot be achieved; at the end of the cycle cold-blowing, the heat exchange area of the cycle air cooler HR needs to be small, otherwise the low-temperature medium will not be fully utilized, resulting in energy waste.

[0099] Therefore, the control method of the present application proposes a heat exchange area automatic adjustment method adapted to the load ratio change of the air suction heat exchange cavity and the air outlet heat exchange cavity. According to the time of the circulating cooling stage or the high-temperature side FH temperature of the air suction heat exchange cavity, the relative position of the partition PA and the heat exchange part HE is changed by using the position adjusting mechanism, the heat exchange area of the air suction heat exchange cavity and the air outlet heat exchange cavity is adjusted in real time, and the cooling speed of the adsorption bed in the circulating cooling process is improved. That is, when the air suction cooling load is large in the initial stage of cooling, the heat exchange part is mainly used for air suction heat exchange; when the air outlet cooling load is large in the final stage of cooling, the heat exchange part HE is mainly used for air outlet heat exchange, so as to ensure that the whole circulating cooling process continuously realizes better heat exchange effect.

[0100] Specifically, the calculation method and basic principle of the proportion of the heat exchange area of the above-mentioned two air suction heat exchange cavities and air outlet heat exchange cavities to the total area of the circulating air cooler are as follows:

[0101] I. Calculation method based on the time of the circulating cooling stage

[0102] The cooling speed refers to the temperature reduction amount of an object per unit time, which is the derivative of temperature with respect to time in mathematics. Experiments show that when the external medium properties and temperature of the same object are the same, and the object properties and surface area are also the same, the cooling rate of the object and the temperature difference between the low-temperature medium and the object exist the following correlation:

[0103]

[0104] Where dT / dt is the rate of change of the temperature T of the object with respect to time t, i.e. the cooling rate; k is the cooling coefficient; T1 represents the low-temperature medium temperature; and T2 represents the high-temperature object temperature.

[0105] During the operation of the air blowing heat regeneration dryer, the load of the air suction heat exchange cavity of the circulating air cooler HR will gradually decrease with the continuous advancement of the circulating cooling process, and the cooling rate of the adsorption bed will also gradually decrease. Considering the cooling rate of the adsorption bed, the load change of the air suction heat exchange cavity, and the influence of the cross-sectional area of the air suction heat exchange cavity of the circulating air cooler on the system operation resistance, the present scheme proposes a real-time optimal heat exchange area calculation method for the air suction heat exchange cavity based on the time of the circulating cooling stage of the air blowing heat regeneration dryer, which is as follows:

[0106] S1: Set the minimum value R1 of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, set the maximum value R2 of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, and set the starting action time t0 of the partition;

[0107] S2: Any adsorption tower is in the circulating cooling stage, and the time of entering the stage is less than t0, the heat exchange area of the air suction heat exchange cavity is determined according to the following formula:

[0108]

[0109] S is the total heat exchange area of the circulating air cooler, in m 2 ; R1 is the minimum set value of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, dimensionless; R2 is the maximum set value of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, dimensionless;

[0110] S3: Any adsorption tower is in the circulating cooling stage, and the time entering the stage is less than t0, the air suction heat exchange cavity heat exchange area S1 is determined according to the following formula:

[0111]

[0112] Wherein, t is the time of the cycle circulating cooling stage (the time of the cycle circulating cooling stage has been performed), in min; t R is the set value of the total time of the cycle circulating cooling stage, in min.

[0113] II. Calculation method based on the temperature of the high-temperature side of the air suction heat exchange cavity

[0114] Since the circulating air is dry air from the adsorption tower, no condensate is generated during the operation of the circulating air cooler HR. The enthalpy h of the circulating air can be obtained by the following formula:

[0115]

[0116] Wherein, h is the enthalpy of the circulating air, in kJ / kg; T is the temperature of the circulating air, in ℃; d is the humidity content of the circulating air, in kg / kg; C p is the specific heat capacity of air at constant pressure (in kJ / ( ), which represents the heat required to raise the temperature of unit mass of air by 1℃).

[0117] Therefore, the heat load of the air suction heat exchange cavity is:

[0118]

[0119] Wherein, Q1 is the heat load of the air suction heat exchange cavity (in kJ / h, representing the heat removed from the gas by heat exchange in the cavity per unit time); R1 is the minimum set value of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, dimensionless; R2 is the maximum set value of the heat exchange area ratio of the air suction heat exchange cavity to the air outlet heat exchange cavity, dimensionless;

[0120] h FH is the enthalpy of the high-temperature side (FH) of the air suction heat exchange cavity (in kJ / kg, enthalpy is a parameter of the energy state of the gas, including sensible heat and latent heat);

[0121] h FL is the enthalpy of the low-temperature side (FL) of the air suction heat exchange cavity (in kJ / kg);

[0122] q m is the mass flow rate of the circulating air (in kg / h, representing the mass of the gas flowing through the air suction heat exchange cavity per unit time).

[0123] T FH is the temperature of the gas on the high-temperature side (FH) of the air suction heat exchange chamber (unit: ℃);

[0124] T FL is the temperature of the gas on the low-temperature side (FL) of the air suction heat exchange chamber (unit: ℃).

[0125] The formula shows that the heat load of the air suction heat exchange chamber is proportional to “the temperature drop of the gas in the chamber (T FH -T FL )”, “the mass flow rate of the gas q m ”, and “the constant-pressure specific heat capacity of air C p ”, which intuitively reflects how much heat the air suction heat exchange chamber needs to take away, and provides a basis for subsequent calculation of the heat exchange area and adjustment of the heat exchange capacity.

[0126] The logarithmic mean temperature difference ΔT m of the air suction heat exchange chamber is:

[0127]

[0128] where T FH is the high-temperature side temperature of the air suction heat exchange chamber (℃); T FL is the low-temperature side temperature of the air suction heat exchange chamber (℃); T RI is the inlet temperature of the low-temperature medium (℃); T RO is the outlet temperature of the low-temperature medium (℃); and K is the total heat transfer coefficient (unit ).

[0129] The logarithmic mean temperature difference ΔT m reflects the average “driving force” of heat exchange between the high-temperature gas (from T FH to T FL ) and the low-temperature medium (from T RI to T RO ) in the air suction heat exchange chamber. The larger this value is, the higher the average level of the temperature difference between the two is, and the higher the heat exchange efficiency is. This provides a core basis for subsequent calculation of the required heat exchange area (such as S1) of the air suction heat exchange chamber, and further optimizes the heat exchange capacity by adjusting the position of the partition.

[0130] That is, the theoretical heat exchange area S1 of the air suction heat exchange chamber is:

[0131]

[0132] Similarly, the theoretical heat exchange area S2 of the air exhaust heat exchange chamber is:

[0133]

[0134] where S2 is the theoretical heat exchange area of the air exhaust heat exchange chamber (unit m 2; ΔT m is the logarithmic mean temperature difference of the air suction heat exchange chamber, unit: ℃; T DH is the high temperature side temperature of the air outlet heat exchange chamber, unit: ℃; T DL is the low temperature side temperature of the air outlet heat exchange chamber, unit: ℃.

[0135] The optimal contact area ratio (or called target area ratio) R of the final air suction heat exchange chamber area S1 and the air outlet heat exchange chamber area S2 is:

[0136]

[0137] Therefore, when the total heat exchange area of the circulating air cooler HR meets the design requirements, the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber determined according to the above formula can effectively match the load ratio fluctuation caused by the change of the air suction temperature, and obtain better cooling efficiency. Further, in order to avoid that the air suction heat exchange chamber or the air outlet heat exchange chamber has too small cross-sectional area, causing the resistance of the circulating air cooler to abnormally rise, the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber must also be within a reasonable range.

[0138] Based on the above calculation and research results, the application proposes the optimal heat exchange area ratio adjustment scheme of the air suction heat exchange chamber and the air outlet heat exchange chamber of the circulating air cooler as follows:

[0139] When R≤R1, adjust the position of the partition plate PA to make the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber R1;

[0140] When R1

[0141] When R≥R2, adjust the position of the partition plate PA to make the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber R2;

[0142] Wherein, R1 is the minimum set value of the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber; R2 is the maximum set value of the heat exchange area ratio of the air suction heat exchange chamber and the air outlet heat exchange chamber. Further, the value of R1 is preferably 0.3-0.45; the value of R2 is preferably 4-6. By adjusting the position of the partition plate through the position adjustment mechanism, the actual ratio of S1 and S2 is matched with R, so as to ensure efficient heat exchange during the whole circulating cooling process and reduce energy consumption.

[0143] Example 4

[0144] In order to verify the technical effect of the application, under the condition that the supporting circulating air volume is 110 m 3 / min, the heat exchange medium is industrial cooling water (30℃, 0.4MPa), and the temperature of the activated alumina adsorption bed (8200kg) is reduced from 180℃ to 40℃, the test data of each process are as follows in Table 4:

[0145] Table 4

[0146]

[0147] Note: The primary cooling process is a conventional technical means, and the adjustable two-stage cooling is the technical solution of the present application. The fixed two-stage cooling is to increase an independent secondary cooler at the position of the air blower exhaust outlet based on the primary cooling process.

[0148] The above test data show that, compared with the existing primary cooling process, the adjustable two-stage cooling process of the present application can shorten the single-tower cold blowing stage time of the zero-gas-consumption air blast regenerative dryer by 30.4% and reduce the single-tower cold blowing energy consumption by 26.6%; compared with the fixed two-stage cooling process, the adjustable two-stage cooling process can shorten the single-tower cold blowing stage time of the zero-gas-consumption air blast regenerative dryer by 19.6% and reduce the single-tower cold blowing energy consumption by 18.2%.

[0149] Example 5

[0150] In order to verify the influence of R value selection on the circulating cold blowing efficiency and the comparative experiment, the following experiments were carried out in this example.

[0151] In the selection and configuration process of the air blower, the following conversion relationship exists among the exhaust volume, the air pressure and the power:

[0152]

[0153] In the formula, N is the shaft power of the air blower, the unit is kW; Q W represents the exhaust volume of the air blower, the unit is m 3 / h; P W represents the air pressure, the unit is Pa; η1 is the fan efficiency, dimensionless; η2 is the mechanical transmission efficiency, dimensionless.

[0154] It can be known from the formula that in a single fixed system, the circulating air cooling system resistance is inversely proportional to the exhaust volume of the air blower. Therefore, for the air blast heat regenerative dryer system using the adjustable two-stage cooler, too low R value will lead to too small flow passage cross-sectional area of the suction air cooler, and too high R value will lead to too small flow passage cross-sectional area of the exhaust air cooler, both of which will cause the system resistance to abnormally increase during the circulating cold blowing process, and then greatly reduce the exhaust volume of the air blower in the system, affecting the circulating cold blowing process.

[0155] According to the test conditions of Example 4, the zero-gas-consumption air blast regenerative dryer with an adjustable two-stage cooling circulating air cooler (the total heat exchange area is 190 m 2 ) was selected for fixed comparative experiment with different R values, and the test data are as follows in Table 5:

[0156] Table 5

[0157]

[0158] According to the experimental data above:

[0159] 1) When the R value is less than 1.0, the cooling load of the initial stage of suction is large, the suction is not fully cooled and exceeds the maximum allowable working temperature of the blower, directly triggering the system overheating protection mechanism.

[0160] 2) When the R value is between 1.0 and 6.0, the fixed ratio two-stage cooler circulating air system can work normally, but the single tower cooling time and single tower cooling energy consumption are different when the two heat exchange cavity container ratios are different.

[0161] 3) When the R value is greater than 7, the flow area of the inlet heat exchange cavity is too small, causing throttling effect, resulting in abnormal increase of the circulating air system resistance, and at this time, the comprehensive efficiency of the two-stage cooler circulating air system is lower than that of the circulating air system with only the suction cooler of the blower.

[0162] In summary, when R≤0.1 or R≥7, the two-stage cooling circulating air system cannot be applied to the zero-gas-consumption blast regenerative dryer due to the large system resistance; when R≤1.0, the cooling effect of the suction heat exchange cavity is poor, and the two-stage cooling circulating air system cannot be applied to the high-temperature cooling process of the initial stage of the zero-gas-consumption blast regenerative dryer.

[0163] Based on the above conclusion, the minimum value R1 and the maximum value R2 are selected between 0.2 and 6.5, and the zero-gas-consumption blast regenerative dryer with two-stage circulating air cooler is tested again by using dynamic adjustment method, and the test data are as follows in Table 6:

[0164] Table 6

[0165]

[0166] The test data show that, except when R≤0.2 or R≥6.5, the system pressure drop is high, resulting in high cooling energy consumption at this stage, in other value intervals, the system cooling efficiency and the adjustable range of the circulating air cooler basically show a synchronous change trend. That is, when the R1 value range is 0.3~0.45 and the R2 value range is 4~6, the comprehensive efficiency of the adjustable two-stage cooling circulating air cooling system is better.

[0167] The part of the present application not described in detail is the prior art, so the present application does not describe it in detail.

[0168] It can be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as a limitation on the number.

[0169] Although the present application has been described in some detail by way of illustration and example for purposes of clarity and understanding, at this point many changes and modifications of the application can occur to those skilled in the art, it being noted that all such changes and modifications are meant to be within the scope of the claims.

[0170] The present application is not limited to the above-described best mode for carrying out the application, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in shape or structure, any technical solution having the same or similar technical solutions as the present application falls within the scope of the present application.

Claims

1. A crossflow cooler characterized by, The circulating air cooler comprises: a shell; a partition plate for partitioning an inner portion of the shell into an air intake heat exchange cavity and an air outlet heat exchange cavity; a heat exchange part arranged in the shell and partitioning the air intake heat exchange cavity into an air intake high-temperature side and an air intake low-temperature side and partitioning the air outlet heat exchange cavity into an air outlet high-temperature side and an air outlet low-temperature side; a position adjusting mechanism coupled with the partition plate or the heat exchange part and used for changing effective heat exchange areas of the air intake heat exchange cavity and the air outlet heat exchange cavity with the heat exchange part respectively; wherein the air intake high-temperature side, the air intake low-temperature side, the air outlet high-temperature side and the air outlet low-temperature side are each provided with a gas interface in communication with the outside, and the heat exchange part is provided with a medium interface for flowing of a low-temperature medium; the circulating air cooler is configured to, in a circulating cooling stage of the air blast heat regeneration dryer, make high-temperature gas from an adsorption tower flow through the air intake heat exchange cavity, an air blower and the air outlet heat exchange cavity in sequence and then return to the adsorption tower, and adjust the effective heat exchange areas in real time by the position adjusting mechanism to match a cooling load changing in the circulating cooling stage.

2. A through-circulation air cooler according to claim 1, wherein The position adjusting mechanism comprises a linear motor module or a linear guide rail, and the partition plate reciprocally moves along a direction perpendicular to the heat exchange part under the drive of the linear motor module or the linear guide rail.

3. A through-circulation air cooler as claimed in claim 1 wherein, The heat exchange part is a plate-fin heat exchanger, and the low-temperature medium is selected from water, an alcohol aqueous solution, a hydrofluorocarbon refrigerant or a hydrofluoroolefin refrigerant.

4. A forced air cooler as claimed in claim 3, wherein, The plate-fin heat exchanger is a cross-flow plate-fin heat exchanger, an air-side fin pitch of which is 2.5-4 mm, and a fin height of which is 3-5 mm.

5. An air blast heat regeneration dryer, comprising an air blower, a first adsorption tower and a second adsorption tower which are cyclically switched to work, when any one of the towers is in an adsorption stage, the other tower sequentially completes a pressure relief stage, a heating regeneration stage, a circulating cooling stage and a pressure charging standby stage, characterized in that, the air blast heat regeneration dryer further comprises the circulating air cooler according to any one of claims 1 to 4, the air outlet heat exchange cavity of the circulating air cooler is arranged between an air exhaust end of the air blower and a cold-blowing air inlet of the adsorption tower, and the air intake heat exchange cavity of the circulating air cooler is arranged between a cold-blowing air exhaust outlet of the adsorption tower and an air suction end of the air blower; when any one of the adsorption towers is in the circulating cooling stage, the adsorption tower, the air intake heat exchange cavity, the air blower and the air outlet heat exchange cavity form a closed circulating air flow loop.

6. A control method for the hot-air regenerative dryer according to claim 5, characterized in that, The method comprises: acquiring state information reflecting a progress of the circulating cooling stage; determining a target area ratio of the air intake heat exchange cavity and the air outlet heat exchange cavity according to the state information; driving the position adjusting mechanism to make the effective heat exchange area ratio of the air intake heat exchange cavity and the air outlet heat exchange cavity with the heat exchange part reach the target area ratio; wherein the state information is at least one of a time of the circulating cooling stage having been performed or a gas temperature of the air intake high-temperature side.

7. The control method according to claim 6, characterized by The method of acquiring the state information reflecting the progress of the circulating cooling stage comprises: acquiring a minimum value R1 of a heat exchange area ratio of the air intake heat exchange cavity and the air outlet heat exchange cavity, a maximum value R2 of the heat exchange area ratio and a starting action time t0 of the partition plate; determining the target area ratio of the air intake heat exchange cavity and the air outlet heat exchange cavity according to the state information comprises: When any of the adsorption towers is in the circulating cooling phase and the time of entering the phase is less than t0, the heat exchange area S1 of the air suction heat exchange cavity is determined according to a first preset formula, wherein the first preset formula is: S is the total heat exchange area of the circulating air cooler; When any of the adsorption towers is in the circulating cooling phase and the time of entering the phase is not less than t0, the heat exchange area S1 of the air suction heat exchange cavity is determined according to a second preset formula, wherein the second preset formula is based on R1, R2, the time t of the circulating cooling phase having been executed and the total time setting value t of the circulating cooling phase R Calculation.

8. The control method according to claim 7, characterized by The second preset formula is: where t is the time already elapsed in the cycle cooling phase; t R Set the value for the total time of the cycle cooling phase.

9. The control method according to claim 6, characterized by, based on the high-temperature side temperature T of the air suction heat exchange cavity FH , the low-temperature side temperature T of the air suction heat exchange cavity FL , the high-temperature side temperature T of the air outlet heat exchange cavity DH , the low-temperature side temperature T of the air outlet heat exchange cavity DL , the outlet temperature T of the low-temperature medium RO , and the inlet temperature T of the low-temperature medium RI The third preset formula is derived to calculate the optimal contact area ratio of the air suction heat exchange cavity area S1 and the air outlet heat exchange cavity area S2. When R is less than or equal to R1, the position of the partition plate is adjusted to make the heat exchange area ratio of the two be R1; When R is greater than R1 and less than R2, the position of the partition plate is adjusted to make the heat exchange area ratio of the two be R; When R is greater than or equal to R2, the position of the partition plate is adjusted to make the heat exchange area ratio of the two be R2, wherein R1 is the minimum value of the heat exchange area ratio, and R2 is the maximum value of the heat exchange area ratio. The optimal contact area ratio is taken as a target area ratio.

10. The control method according to any one of claims 7 to 9, characterized in that, The value range of R1 is 0.3-0.45, and the value range of R2 is 4-6.

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