• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a spray drying apparatus comprising; a spray dryer chamber with a feed inlet device, a process air inlet and a proc ess air discharge, a process air temperature measuring means, and a proc ess air heater for heating a process air volume, an adsorption dehumidification device for dehumidification of the process air comprising an adsorption source, a process air section and a regeneration air section and having means for heating a regeneration air volume to a regeneration air tempera ture and means for measuring the regeneration air temperature, and a re generation air fan configured for transporting the regeneration air volume, and moisture content measuring means for determining a moisture content in the air process.
    公开号:DK201100068U1
    申请号:DK201100068U
    申请日:2011-04-04
    公开日:2011-06-24
    发明作者:Clausen Jannik Reiner；Olesen Soeren Roennow；valentin Lars
    申请人:Cotes As；
    IPC主号:
    专利说明:

    DK 2011 00068 U4
    SPRAY DRYER
    The invention relates to a spray dryer as set out in the preamble of claim 1.
    Spray dryers are used to dry a feed material consisting of a solid form and a solvent, for example water, by injecting the feed material into a spray drying chamber, where the feed material is brought into contact with a normally hot process air, which is introduced simultaneously, whereby the solvent evaporates. . The evaporated solvent will be transported with the process air and leave the spray drying chamber at a process air outlet, and the dry matter will be extracted from the lowest part of the spray drying chamber for further treatment and drying most often in a fluid bed apparatus. Typically, special filter arrangements are used to trap particles attempting to escape the spray drying chamber into the process air leaving the chamber.
    In industry, such spray dryers are often very large plants for the production of, for example, instant coffee and milk powder in a constant process flow. Such spray dryers are operated with process air volumes of up to 100,000 kg per hour and with an output of 3-4 tons of dry matter per. hour, and will thus lead to a large energy consumption in the form of energy for heating the process air.
    Within the spray drying area, significant progress has been developed and implemented to increase the efficiency of the spray drying process to increase the capacity measured in kilograms of dry matter produced per. hour.
    In "Spray Drying Hand Book, 5th ed", Chapter 10 by K. Masters, it is assumed that a high relative humidity may necessitate a reduction in the temperature in the intake and thus lead to a reduction in the capacity of the spray dryer (pages 120, 121).
    German DE2158657 A1 describes a spray drying plant with a spray drying column and an adsorption device for dehumidifying process air. Heat exchange takes place between the hot used process air and the material to be spray-dried, between the hot used regeneration air and the cold dry process air, and between the hot used regeneration air and the fresh cold regeneration air.
    US 4,475,295 discloses an installation for dehumidifying a gaseous desiccant using an adsorbent, and with regeneration of the adsorbent. By using the installation, it can be achieved that partial streams of the desiccant can be dried, each with a different moisture content. The paper describes the use of a battery of heat exchangers with varying functions.
    In order to compensate for changes in the moisture content of the process air, it has therefore been well known practice to reduce the feed rate in the light of the reduced spray drying capacity, thereby balancing the evaporation capacity and the actual feed rate. However, this has the undesirable side effect of spraying the spray dryer in an inefficient manner.
    3 DK 2011 00068 U4
    Various improvements to increase the efficiency of the spray drying process involve controlling the manner in which the spray dryer is operated. And as such, it is a normal control practice to keep the temperature and humidity constant in the process air discharged from the outlet of the spray drying chamber to obtain a product which has a substantially constant quality.
    Such a spray dryer is described in WO 2008/077399, which describes a method and an apparatus for keeping the temperature and humidity of the process air at the outlet at a constant level thereby allowing a constant residual moisture content of the dried product. This is achieved by adjusting the process air flow and the process air temperature in relation to the moisture content, whereby it is achieved that the product is produced under constant conditions.
    However, a disadvantage of the method described above is that it necessitates an adjustment of the temperature of the intake air and the air flow in the process in order to obtain a constant evaporation capacity of the spray drying chamber. With regard to energy consumption, this method is particularly dependent on the set point for the specific process and will vary with any change in the moisture content of the process air used in the drying process, and as such necessitates that the spray dryer be operated within a lot wide limits of air volumes, which in turn places great demands on equipment such as process air blowers, piping, and furthermore requires a large energy consumption for heating the process air.
    4 DK 2011 00068 U4
    It is an object of the invention to provide a spray dryer which solves the problems of the prior art.
    This is achieved according to the invention in that the spray drying apparatus comprises a heat exchange device adapted to exchange heat energy from the discharged volume of process air at the process air outlet to regeneration energy for heating a volume of regeneration air where the spray drying apparatus. further comprising a control unit adapted to determine a moisture content based on readings from a moisture content measuring device; and a connection for transmitting information to a device for regulating the regeneration energy on the basis of a comparison of a current reading of the moisture content and a moisture target value or moisture set point (English: moisture set point) to obtain a measured value for the moisture
    This results in a significant increase in the production capacity of the spray dryer, as the process air is able to absorb an increased amount of water, because the enthalpy working line belonging to the specific drying process is extended by reducing the moisture content and increasing the temperature of the process air by using that energy. which is available in the discharged process air, whereby a process is obtained which makes it possible to increase output per. hour while reducing operating costs.
    Other advantageous embodiments of the invention appear from the dependent claims.
    5 DK 2011 00068 U4
    The invention will be described in detail in the following with reference to the schematic drawings, in which - figure 1 shows a schematic diagram of a spray dryer according to the invention, - figure 2a, in perspective, shows details of a rotor section with a rotor for a spray dryer according to the invention , - figure 2b shows a section through the rotor section in figure 2a from the side, and where - figure 2b shows the rotor section from figure 2a from the front.
    Figure 1 shows a schematic diagram of a spray dryer comprising a spray dryer chamber 10 with a feed device 11, a process air inlet 12 and a process air outlet 13, which are connected to relevant filters 13b, and a process air blower 13a adapted to transport process air. Furthermore, a feed material feed line 15a and a feed material feed line system (not shown) are connected to the feed device 11, which is well known and as a result, this will not be described in further detail. The feed device 11 comprises an atomizer (not shown) of a type known in the art as a nozzle or a rotary atomizer (not shown) for injecting feed material into the spray drying chamber 10.
    A process air intake duct 15 is connected to the process air inlet 12, and a process air heating device 17 is arranged to heat the process air to a process air intake temperature before it is led into the spray drying chamber. The process air heater 17 in this embodiment is a steam heater operating with saturated steam. Other types of heating devices adapted to the use will naturally be able to be used.
    A process air temperature measuring device 16, which may normally be an electronic temperature sensor 16, is arranged in the process air intake duct 15 or connected to a control unit 100.
    An adsorption dehumidification device for dehumidifying the process air is connected to the process air intake duct 15 and arranged between a filter arrangement (not shown) and the process air heating device 17.
    With reference to Figures 2a, 2b and 2c, the function of the dehumidifier device is described below, which dehumidifier device is also called a dehumidifier, and in this description reference is made to the sectional views of the rotor section of the dehumidifier in Figures 2b and 2c. The dehumidifier comprises an adsorption source in the form of a cylindrical adsorption rotor 41 with channels extending from a first cylinder end surface 41a to a second cylinder end surface 41b, and which is impregnated with an adsorption agent / an adsorbent material / an adsorbent, which in most cases will be a type silica gel or lithium chloride, which will remove water from the volume of process air brought into contact with the agent. "Adsorption" is also referred to as "sorption".
    The rotor 41 is mounted in centrally located bearings which allow rotation of the rotor 41. A drive device comprising a motor 29 is arranged to drive the rotation 7 of a rotor 41 about a central axis 33 at a given speed suitable for the dehumidification process . Normally the rotor has a fixed rotational speed, but in certain special cases it may be necessary to adjust the rotational speed in order to optimize the effect of the dehumidification process.
    The dehumidifier comprises a process air section 43 and a regeneration air section 44, which sections are separated from each other by gaskets 45 which separate the process air stream from the flow of the regeneration air. In Figure 2, the regeneration air section is shown with the reference "R", and the process air section is shown with the reference "P".
    It will be appreciated that process air denotes the air to be dehumidified. The term "dry air" can be used about the dehumidified process air, ie. the air that has been passed through the ducts of the rotor. Regeneration air is the term used for a heated volume of air passed through the regeneration section 44, which is used to evaporate the water absorbed in the rotor 41. The regeneration air volume will normally be heated to a temperature necessary for the dehumidification process, and as such will contain a specific energy. We therefore understand that this energy is obtained on the basis of a combination of the flow of the regeneration air volume and the temperature of the regeneration air.
    In use, the rotor 41 rotates slowly and, as it passes the process air section 43, will saturate with water molecules. When the rotor 41 is further rotated over to the regeneration section or zone, the absorbed water will evaporate using the heated regeneration air, and the rotor 41 is thereby regenerated so that it can again absorb water molecules from the process air. In a preferred embodiment of the generator, the dehumidifier is arranged with a regeneration air section 44 and a process air section 43 which are substantially equal in size, whereby each section will absorb 180 ° out of the total 360 ° circular surface of the rotor. In special cases a division with a process air section 43 extending over 270 ° and a regeneration air section extending over 90 ° may be used, or in other cases other combinations therebetween, for example 240 ° for process air and 120 ° for regeneration air.
    The division between process air and the regeneration air sections of 180 ° / 180 ° is particularly advantageous in situations where a large volume of process air is discharged at a low temperature, as this causes the air volume to be passed through the rotor 41 with a pressure drop but still capable of achieving an efficient regeneration of the rotor, as the total energy recovered can be used for regeneration.
    In other situations, the division of process air and regeneration air sections into 270 ° / 90 ° or 240 ° / 120 ° will be particularly advantageous.
    Referring again to Figure 1. A temperature sensor 25 is installed between a regeneration air heater 22 and the rotor 41, and is intended for detecting the regeneration air temperature of the regeneration air.
    9 DK 2011 00068 U4
    A regeneration air duct 14 is arranged to transport a regeneration air volume using a regeneration air blower 30, which with a filter 14a, rotor 41 and one or more regeneration air heaters 22, 23 is arranged in the regeneration air duct 14 on the suction side of the blower 30. motor 31a, which is equipped with a device for regulating the regeneration air flow, which device in a preferred embodiment is a frequency inverter (English: frequency inverter, not shown) which is connected to the control unit 100. Alternatively, a regulating damper (English: regulating damper). ) is arranged in the regeneration air duct 14 for regulating the regeneration air volume. In such cases, the regulating damper will be equipped with an actuator connected to the control unit as indicated by the dashed line 31b.
    Before the regeneration air is passed through the rotor 41, it is heated using a twin coil heat exchanger 20 which includes a discharge coil 21 to extract heat energy from hot process air discharged from the spray drying chamber 10, which energy is transferred to heating the regeneration air by means of a regeneration air coil 22. A circulation pump 24, connected between the coils 21, 22, establishes a closed circuit using piping for circulation of a liquid medium suitable for energy transfer. The circulation pump 24 is connected to a suitable device for controlling the flow of liquid, and is preferably connected to the control unit 100.
    Normally, the desired discharged process air temperature and the relative humidity of the process air are determined based on the relationship to the specific drying process and the product to be spray-dried. An emission temperature in the range of 70-110 ° and a corresponding relative humidity of 4-10% is often used as the target value or set point (English: set point).
    An additional regeneration air heating unit 23 can additionally be installed between the regeneration air heater 22 and the rotor 41 in case there is a need to increase the regeneration air temperature to a temperature level which can not be obtained by using the recovered energy from the heat recovery unit alone. This will normally only be relevant during the start-up phase of the spray dryer, where the temperature of the discharged air has not yet reached normal operating level. The heating unit 23 is provided with a control device connected to the control unit 100 in order to regulate the heating effect of the heating unit. The heating unit 23 can be a heating coil (English: heating coil) driven by steam or water, or a gas heating unit for direct or indirect combustion of gas.
    As described above, a regeneration air temperature sensor 25 is arranged between the regeneration air heating unit and the rotor 41. The regeneration air temperature sensor 25 is arranged to measure the regeneration air temperature, and is connected to the control unit 100. In a preferred embodiment, the regeneration air temperature 25 is a regeneration air temperature sensor.
    In combination with the adjustment of the regeneration air temperature and / or the regeneration air volume, it may be preferable to control the rotational speed of the rotor 41 in relation to the target value of the moisture content (English: set point). To achieve this, the control unit is connected to a frequency inverter (English: frequency inverter, not shown) which controls the speed of the motor 29.
    In addition, a control damper (not shown) may be connected to the regeneration air duct to regulate the regeneration air volume. Normally, the control damper will be provided with an actuator connected to the control unit 100 in order to regulate the regeneration air flow.
    A process air temperature measuring device 16, which is connected to the control unit 100, is arranged between the process air intake 12 and the process air heating device 17 in the process air intake duct. A moisture content measuring device, for example in the form of a moisture sensor 19 for determining the moisture content of the process air, is additionally installed in the process air intake duct 15, and connected to the control unit 100. The moisture content is measured in [g / kg] and determined on the basis of a measured relative humidity. corresponding temperature, and as such the moisture content measuring device comprises a temperature sensor 18 and a humidity sensor 19.
    12 DK 2011 00068 U4
    As described above, the control unit 100 is connected to said regeneration air temperature sensor 25, the frequency converter 31c, the temperature sensor 18 and the humidity sensor 19, and the process air temperature measuring device 16.
    The control unit 100 is arranged to regulate the moisture content of the process air to be used in the spray drying chamber in relation to a desired moisture content target value (set point).
    The moisture content is determined on the basis of measurements of the temperature of the process air, which measurement is received from the temperature sensor 18, and on the basis of measurements of the relative humidity, which measurement is received from the moisture sensor 19. These measurements are compared with the moisture content target value (set point). or the absolute or relative water content), and the control unit regulates the regeneration air volume on the basis of the comparison to obtain a measured value of the moisture content equal to the target value (set points).
    It is seen that the regeneration air volume flow can be regulated between a minimum and a maximum limit. If in some cases the moisture content cannot be changed to reach the target value (set point) by regulating the regeneration air volume to the maximum limit, the control unit will send signals to a control device (not shown) arranged to regulate the heating power of the heating unit. 23 by adjusting the supply of heat power to the heating unit 23. The measurements of the moisture content are compared with the target value of the moisture content (set points), and the control unit 13 DK 2011 00068 U4 regulates the heat power supply on the basis of the comparison to adjust the measured value of the moisture content the set point value of the moisture content.
    In the event that the measured moisture content is lower than the target value of the moisture content (set points), the supplied regeneration energy will normally be reduced to a level until the measured moisture content is again equal to the target value of the moisture content (set points).
    Normally, the temperature of the process air to be used in the spray drying chamber is strongly linked to the specific spray drying process and the product to be dried, and as such, a process air temperature target value (set point) will be assigned and entered into the control unit 100.
    The measurements of the process air temperature are compared with the target value of the process air temperature (set point), and the control unit regulates the heat power supply on the basis of the comparison to achieve that the measured value of the process air temperature is adjusted to the target air temperature target value (set point).
    In the following examples, a comparison is made between a spray dryer according to the prior art and a spray dryer according to the invention. In the example, the moisture content of the ambient air is 22g / Kg [grams of water / kilogram of dry air].
    Example 1:
    Ambient conditions: 30 ° C, 22 g / kg
    Process air temperature at intake 180 ° C
    Moisture content at intake 22 g / kg
    14 DK 2011 00068 U4 Process air temperature at the outlet oo o 0 O Moisture content at the outlet 60 g / kg Moisture removal capacity 3830 kg / hour Production at 6000 operating hours 22980 tonnes / year Energy consumption: Process air heating 4396 kW Dehumidification 0 kW Total energy consumption 4396 kW Operating hours for 23000 tons year 6005 hours / year Example 2: Ambient conditions: 30 ° C, 22 g / kg Process air temperature at the inlet 209 ° C Moisture content at the inlet 10 g / kg Process air temperature at the outlet OO oo O Moisture content at the outlet 60 g / kg Moisture removal capacity 5045 kg / hour Production at 6000 operating hours 30270 tons / year Energy consumption: Process air heating 3948 kW Dehumidification 1525 kW Heat recovery -622 kW Total energy consumption 4851 kW Operating hours for 23000 tons / year 4559 hours / year Example 3: Ambient conditions: 30 ° C, 22 g / kg Process air temperature at inlet 209 ° C
    15 DK 2011 00068 U4 10 g / kg 80 ° C 60 g / kg
    Moisture content at inlet Process air temperature at the outlet Moisture content at the outlet
    Dehumidifier capacity 5050 kg / hour
    Production at 6000 operating hours · 30300 tons / year
    Energy consumption:
    4017 kW 1699 kW -1033 kW 4683 kW
    4554 hours / year
    Process air heating Of humidification Heat recovery Total energy consumption
    Operating hours for 23000 tons / year
    The data relating to the prior art are given in Example 1. In Examples 2 and 3, data concerning the spray dryer according to the invention are given. In Example 2, the dehumidifier is provided with a regeneration section of 90 ° and a process air section of 270 °, and in Example 3, regeneration section and process air section occupy 180 ° each of the circular surface.
    It has surprisingly been found that the production capacity increases by 24% measured as the number of tons of a product produced per year, compared to a spray dryer according to the prior art. This is achieved by increasing the temperature of the process air at the process air intake and by reducing the moisture content of the process air at the same time by using an adsorption dehumidifier. Although the "process air intake" is increased to a higher temperature, it has been found that by recovering energy from the discharged process air, the capacity of the system is increased, and the process is thereby made more efficient compared to known systems.
    It is therefore seen that taking into account the actual moisture content, the total energy consumption must be increased in order for the process air intake temperature to reach the enthalpy working line (English: enthalpy working line) corresponding to the specific drying process. However, this increase in total energy consumption is compensated for, as most of the energy consumed for the dehumidification process is recovered from the hot process air discharged from the spray drying chamber, as described above and as given in the examples. In addition, the production capacity of the spray drying chamber is increased, as the process air maintains a low moisture content, which has the consequence that the same volume of process air can absorb more moisture while the drying process is kept on the same singular arrow line. In this context, it is seen that the production time, for example, for the production of 23,000 tons is significantly shortened, why a spray dryer will be able to produce the same volume of a product, but at lower cost per ton, and in a shorter time, or why a increased capacity of the spray dryer is achieved so that an increased quantity can be produced at the same cost as now.
    The scope of protection of the article should not be limited to the preferred embodiments shown herein, but are set forth in the following claims. One skilled in the art will be able to suggest modifications to the embodiments, as for example other types of heat exchange devices may be used, such as cross-flow heat exchangers. Likewise, other types of adsorption dehumidifiers can be used, and a wet adsorption dehumidifier using a liquid adsorption agent can be used instead of dehumidifiers using adsorption rotors.
    权利要求:
    Claims (7)
    [1]
    A spray drying apparatus (1) comprising 5 - a spray drying chamber (10) with - a feed material feeding device (11), - a process air inlet (12), and - a process air outlet (13), a process air temperature measuring device (16) , - a process air heating device (17) for heating a process air volume, - an adsorption dehumidifying device for dehumidifying the process air volume, and comprising - an adsorption source (41), - a process air section (43) and - a regeneration air section (44), - a device (22 , 23) for heating a regeneration air volume to a regeneration air temperature, - a device for measuring the regeneration air temperature (25), - a regeneration air blower (30) arranged to transport the regeneration air volume, and - a moisture content measuring device (18, 19) for determining process air, characterized in that the spray-drying apparatus (1) further comprises - a device for heat exchange so m is arranged to exchange heat energy from the process air volume, which is discharged from the process air outlet (13), to regeneration energy to heat the regeneration air volume, - a control unit (100) arranged to determine a moisture content on the basis of measurements from the moisture content measuring device (18, 19), and - a connection for supplying information to a device for regulating the regeneration energy on the basis of a comparison to obtain a measured value for the moisture content equal to a moisture content target value.
    [2]
    A spray dryer according to claim 1, characterized in that a motor (31a) of a regeneration air blower is provided with a control device for regulating the air volume, which control device is connected to the control unit (100).
    [3]
    A spray drying apparatus according to any one of claims 1-2, characterized in that the moisture content measuring device is arranged to measure the moisture content of the process air after the adsorption dehumidifying device.
    [4]
    A spray dryer according to any one of claims 1-3, characterized in that the adsorption dehumidifying device comprises a cylindrical rotor with adsorbent properties, which adsorption dehumidifying device is arranged with a plurality of channels extending through the adsorption dehumidifying device from a first cylinder end surface (41a) to a second cylinder end face (41b), thereby allowing the passage of process air and regeneration air, and which adsorption dehumidifying device is provided with a rotating device (29) for controlling the rotational speed of the rotor (41).
    [5]
    A spray dryer according to any one of claims 1-4, characterized in that the adsorption dehumidifying device is subdivided into process air and regeneration air sectors of 180 ° / 180 ° respectively.
    [6]
    A spray dryer according to any one of claims 1-4, characterized in that the adsorption dehumidifying device is subdivided into 270 ° / 90 ° process air and regeneration air sectors, respectively. 15 and
    [7]
    A spray dryer according to any one of the preceding claims, characterized in that the moisture content measuring device (18, 19) is arranged between the adsorption source (41) and the process air heating device (17). 20 DK 2011 00068 U4 DK 2011 00068 U4


    DK 2011 00068 U4 DK 2011 00068 U4
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    同族专利:
    公开号 | 公开日
    DK201100068U4|2012-07-27|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2020-03-06| UUP| Utility model expired|Expiry date: 20200305 |
    优先权:
    申请号 | 申请日 | 专利标题
    EP01000173A|EP1160622A1|2000-05-27|2001-05-22|A bleach-fixing concentrate|
    DKBA201100068U|DK201100068U4|2001-05-22|2011-04-04|Spray Drying Device|DKBA201100068U| DK201100068U4|2001-05-22|2011-04-04|Spray Drying Device|
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