RU2048129C1 - Method and installation for drying friable materials - Google Patents

Abstract

FIELD: agricultural engineering. SUBSTANCE: method involves transportation of materials, providing for their interaction with a hot heat carrier, and drying. The hot heat carrier is moved inside an auger in the same direction with the transported drying mass. Then the heat carrier is desiccated and directed against the movement of the drying mass. The latter is carried from one hopper to another and dried on a closed cycle until a certain terminal humidity of the mass is reached. The drying installation comprises two and more hoppers combined into a closed system; a transportation and mass-drying unit has the form of auger 17 with hollow shaft 18 enclosed into sealed pipe 20 with dried and heated heat carrier. The heat carrier heating unit has successively- connected filters 8, compressor 9 and heater 10 while the moisture-separating unit comprises heat exchanger 6, turbo- expansion engine 11, moisture separator 12 and fan 13. EFFECT: improved functional and operating characteristics. 2 cl, 2 dwg, 1 tbl

Description

 The invention relates to agricultural machinery and can be used for the preparation of animal feed, in particular for drying feed.

Known auger-type drying unit containing a hopper with a drying mass, nodes for transporting the drying mass in the form of two shafts rotating in opposite directions, nodes for heating the coolant, moisture separation and heat exchanger [1]
A disadvantage of the known drying installation is the relatively low efficiency and increased energy consumption of the drying process.

There is also known a method of drying bulk materials, including transporting the drying mass, heating the coolant in the form of a mixture of gases of a special composition, ensuring the interaction of the coolant with the drying mass [1]
The disadvantage of this known method is the need for the formation of a special composition of gases and, therefore, the need for additional equipment (gas generator).

Known drying installation containing bins with a drying mass, nodes for transporting and drying the drying mass, nodes for heating the coolant, moisture separation and heat exchanger [2]
A known method of drying bulk materials, including transporting the drying mass, heating the coolant and passing it through the drying mass, subsequent drying of the coolant [2]
The disadvantages of the prototypes are relatively high drying temperatures and the associated high loss of nutrients, high energy consumption per unit mass of moisture removed, insufficient environmental friendliness of the device.

 The aim of the invention is to reduce the drying temperature to prevent loss of nutrients and reduce energy consumption per unit mass of moisture removed.

≅

+2,1

-1 где d₂ наружный диаметр шнека,
d₁ внутренний диаметр трубы шнека, а соотношение объема V₂ и объема V₃ каждого бункера выбрано в пределах
1 ≅

≅ 3,1
Поставленная цель достигается также в способе сушки сыпучих материалов, включающем транспортировку сушильной массы, подогрев теплоносителя, обеспечение взаимодействия его с сушильной массой и осушение теплоносителя, тем, что теплоноситель сжимают до давления Р в пределах (0,15-0,29) МПа и дополнительно нагревают до температуры Т в пределах (410-460) К, подают теплоноситель во внутреннюю полость шнекового транспортера и прогревают сушильную массу, перемещая теплоноситель и сушильную массу в одном направлении и поддерживая соотношение скоростей V₁ теплоносителя и V₂ сушильной массы в пределах
0,001 ≅

≅ 0,01 затем охлаждают теплоноситель до температуры Т₁ по отношению к его температуре Т₂ на входе в шнек в пределах
0,62 ≅

≅ 0,75 и снижают его влагосодержание С₁ по отношению к его влагосодержанию С₂ в пределах
0,76 ≅

≅ 1 после чего теплоноситель направляют к вентилятору, причем расход теплоносителя G₁ через турбину турбодетандера поддерживают по отношению к расходу G₂ через вентилятор в пределах
0,88 ≅

≅ 1 Затем осушенный теплоноситель направляют навстречу движущейся сушильной массе, обеспечивая совместно с контактным нагревом ее деталей узла транспортировки итоговую температуру Т_см сушильной массы в пределах (295-335) К, а отработанный, насыщенный влагой теплоноситель фильтруют, сжимают, нагревают и снова подают во внутреннюю полость узла транспортировки, при этом осуществляя транспортировку и сушку сушильной массы из бункера в бункер по замкнутому циклу, суммарную длительность сушки поддерживают до достижения конечной влажности С₃ сушильной массы по отношению к ее начальной влажности С₄ в пределах
0,1 ≅

≅ 1
На фиг. 1 дана конструктивная схема выполнения сушильной установки; на фиг. 2 конструктивное выполнение одного из функциональных узлов сушильной установки.This goal is achieved in a drying installation containing hoppers with a drying mass, nodes for transporting and drying the drying mass, nodes for heating the heat carrier, nodes for separating moisture and heat exchangers, by the fact that the filter heating unit includes series-connected filters, a compressor and a heater, and the moisture separation unit includes a series-connected heat exchanger, turbo-expander, dehumidifier and fan, mounted on the turbine-expander turbine shaft, two or more bins with a drying mass of are connected in a closed system in such a way that the lower part of the first hopper through a dosing device is hermetically connected to the transport and drying unit of the drying mass, which is made in the form of a screw with a hollow inner pipe, equipped with rotating hermetic joints at the ends, and enclosed inside the external pressurized pipe drained coolant, the receiving part of the internal cavity of the screw through the pressurized unit is connected to the output of the heating medium heating unit, and the external cavity for the supply of the dried coolant la is connected to the input node coolant heating. The output of the drying mass transportation unit is connected to the upper receiving part of the second hopper, and the internal cavity of the output end of the screw is connected through a rotating pressure node to the first input of the heat exchanger, the first output of which is connected through the turbine expander and moisture separator to the second input of the heat exchanger, and the second output of the heat exchanger with the fan input, output which is connected to the receiving part of the external supply pipe of the dried coolant. The lower feed part of the second hopper, respectively, through a metering device, is connected to the second conveying and drying unit of the drying mass, similar to the first drying unit, which in its supply part is connected to the upper receiving part of the subsequent hopper and to the heat exchanger, the drying units of the heat carrier of the subsequent hopper, similarly to the connection of the output part the first unit of transportation and drying with the upper receiving part of the second hopper and the heat exchanger of the drying unit of the coolant of the second hopper, and the supply and Receiving part of the third, fourth, etc. hoppers are connected in a similar way, however, the feed part of the last hopper is connected to the receiving part of the first hopper, each of the hoppers is equipped with inlet and outlet valves of the starting coolant from an autonomous source, and the ratio of the volume V _{1 of the} internal cavity of each screw to the volume V _{2 of} each external cavity of the supply of the dried coolant selected within:
2.1 ≅

≅

+2.1

-1 where d _{2 is the} outer diameter of the screw,
d _{1 the} inner diameter of the screw pipe, and the ratio of the volume V ₂ and volume V _{3 of} each hopper is selected within
1 ≅

≅ 3.1
The goal is also achieved in the method of drying bulk materials, including transporting the drying mass, heating the coolant, ensuring its interaction with the drying mass and draining the coolant, so that the coolant is compressed to a pressure P in the range (0.15-0.29) MPa and additionally heated to a temperature T in the range of (410-460) K, the coolant is fed into the internal cavity of the screw conveyor and the drying mass is heated, moving the coolant and the drying mass in one direction and maintaining the speed ratio th V ₁ coolant and V ₂ drying mass within
0,001 ≅

≅ 0.01 then cool the coolant to a temperature of T ₁ with respect to its temperature T ₂ at the entrance to the screw within
0.62 ≅

≅ 0.75 and reduce its moisture content With ₁ in relation to its moisture content With ₂ within
0.76 ≅

≅ 1 after which the coolant is directed to the fan, and the flow rate of the coolant G ₁ through the turbine of the expander is supported with respect to the flow rate of G ₂ through the fan within
0,88 ≅

≅ 1 Then, the drained heat carrier is directed towards the moving drying mass, together with the contact heating of its parts of the transportation unit, providing the final temperature T _{cm of the} drying mass within (295-335) K, and the spent heat-saturated coolant is filtered, compressed, heated and fed back to internal cavity transport node, the implementing transport and drying of the drying mass from the hopper to the hopper in a closed cycle, the total drying time is maintained until the final moisture _C3 ushilnoy mass towards its initial moisture content in the range of C ₄
0,1 ≅

≅ 1
In FIG. 1 is a structural diagram of a drying installation; in FIG. 2 constructive implementation of one of the functional units of the drying installation.

 The node contains hoppers 2 with a drying mass, nodes 3 transporting the drying mass, nodes 4 for heating the coolant, nodes 5 for separating moisture.

 Filters 8, a compressor 9 and a heater 10 are connected in series with each other in a heating medium heating unit 4 (Fig. 2), and a heat exchanger 6, a turboexpander 11, a moisture separator 12, and a fan 13 mounted on the turbine shaft 14 are connected in series to the moisture separation unit 5 turbo expander.

 Two or more hoppers 2 with a drying mass are combined into a closed system (Fig. 1) so that the lower part 15 of the first hopper is hermetically connected through a metering device 16 to the transport and drying unit 3 of the drying mass, which is made in the form of an auger 17 with an internal hollow a pipe 18, provided at the ends with rotating hermetic nodes 19, and enclosed inside an external pressurized pipe 20 of a forcibly supplied dried heat carrier 21.

 The receiving part 22 of the internal cavity of the screw 17 through the pressurized 19 is connected to the outlet of the heating medium heating unit 4, and the outer cavity of the pipe 20 for supplying the dried coolant 21 is connected by a pipe 23 to the input of the heating medium heating unit 4.

 The output of the drying mass transportation unit 3 is connected to the upper receiving part 24 of the second hopper 25, and the internal cavity 18 of the output end of the screw 17 is connected through the rotary hermetic node 19 to the first input 26 of the heat exchanger 6. The first output 27 of the heat exchanger 6 is connected through the turbine expander 11 and the moisture separator 12 to the second the input 28 of the heat exchanger 6, and the second output 29 with the input of the fan 13. The output of the latter is connected to the receiving part of the outer pipe 20 for supplying the dried coolant 21.

 The lower feed part of the second hopper 25, respectively, through the metering device 16 is connected to the second node 30 for transporting and drying the drying mass similar to the first drying unit, which contains the hopper 2, node 3 for transporting and drying the drying mass and node 5 for separating moisture.

 This drying unit with its supplying part is connected to the upper receiving part of the subsequent hopper (or the first hopper with a total number of bins equal to 2) and a heat exchanger, drying units of the heat carrier of the subsequent hopper, similar to connecting the output part of the first transportation and drying unit with the upper receiving part of the second hopper and the heat exchanger of the heat carrier drying unit of the second hopper.

 The supply and receiving parts of the third 31, fourth 32, etc. hoppers are connected in a similar way, however, the feed part of the last hopper 33 (Fig. 1) is connected to the receiving part of the first hopper 2.

 Each of the bins is equipped with inlet 34 and outlet 35 valves of the starting coolant 36 from an autonomous source (air can be sucked in as a coolant from the atmosphere).

≅

+2,1

-1 где d₂ наружный диаметр шнека;
d₁ внутренний диаметр трубы шнека, а соотношение объема V₂ и объема V₃ каждого бункера выбрано в пределах
1 ≅

≅ 3,1
Принципом действия заявленной сушильной установки является способ сушки в ней сыпучих материалов, поэтому описание заявленного способа сушки является одновременно и описанием работы заявленного устройства.The ratio of the volume V _{1 of the} inner cavity 18 of each screw 17 to the volume V _{2 of} each outer cavity 20 of the dried coolant 21 is selected in the range:
2.1 ≅

≅

+2.1

-1 where d _{2 is the} outer diameter of the screw;
d _{1 the} inner diameter of the screw pipe, and the ratio of the volume V ₂ and volume V _{3 of} each hopper is selected within
1 ≅

≅ 3.1
The principle of operation of the claimed drying installation is a method of drying bulk materials in it, therefore, a description of the claimed drying method is at the same time a description of the operation of the claimed device.

 In accordance with the claimed method, the coolant 7 is compressed to a pressure P in the range (0.15-0.29) MPa and is additionally heated to a temperature T in the range (410-460) K. To do this, in the start-up mode of the installation using the inlet valve 34 from an autonomous source or from the atmosphere serves the coolant 36 into the hopper 25 into the outer tube 20 of the transport and drying unit 3, the output of which is connected to the input of the filter 8.

≅ 0,01
Затем охлаждают теплоноситель до температуры Т₁ по отношению к его температуре Т₂ на входе в шнек в пределах
0,62 ≅

≅ 0,75 и снижают при этом его влагосодержание С₁ по отношению к его влагосодержанию С₂ в пределах
0,76 ≅

≅ 1
Это достигается путем пропускания теплоносителя через гермоузел 19, первый вход 26 теплообменника 6, через турбодетандер 11, влагоотделитель 12, второй вход 28 теплообменника 6, через вентилятор 13 посаженного на один вал 14 турбодетандера 11.Thus, the drying mass 37 is heated, moving the coolant 7 and the drying mass in one direction, maintaining the ratio of the speeds V _{1 of the} coolant 7 and V _{2 of the} drying mass 37 within
0,001 ≅

≅ 0.01
Then cool the coolant to a temperature of T ₁ with respect to its temperature T ₂ at the entrance to the screw within
0.62 ≅

≅ 0.75 and at the same time reduce its moisture content C ₁ with respect to its moisture content C ₂ within
0.76 ≅

≅ 1
This is achieved by passing the coolant through the pressurized node 19, the first inlet 26 of the heat exchanger 6, through the turbo expander 11, the moisture separator 12, the second inlet 28 of the heat exchanger 6, through the fan 13 mounted on one shaft 14 of the turbo expander 11.

Thus dried and heated coolant 21 is directed towards the moving drying mass 37 and above it, together with contact heating from the parts of the conveying unit 3 (mainly from the inner tube 18 of the screw 17), the final temperature T _{cm of the} drying mass 37 is in the range (295-335) TO.

 Next, the spent, moisture-saturated coolant 7 is filtered by a filter 8, compressed by a compressor 9, the heater 10 is heated, if necessary, and again fed through a rotating pressure unit 19 into the internal cavity 18 of the drying mass transporting unit 3. At the same time, the drying mass 37 is transported and dried from the hopper. in hopper 2 in a closed loop.

≅ 1
В целях предотвращения перегрузки бункеров 2 сушильной массой 37 в нижней части 15 каждого из них установлены дозаторы 16, регулирующие количество сушильной массы.As a result, the total drying time is maintained until the final humidity C _{3 of the} drying mass 37 is reached with respect to its initial humidity C ₄ within
0,1 ≅

≅ 1
In order to prevent overloading of the bins 2 with a drying mass 37, at the bottom 15 of each of them, dispensers 16 are installed that control the amount of drying mass.

 In the case of stopping the drying process in the drying unit, the excess pressure of the coolant in the pipe 18 is released through the valve 35.

 The achievement of this goal was monitored by determining the ratio of α energy consumption per unit of moisture removed in known objects compared with the declared objects.

 Examples of practical implementation are summarized in table.

 The table clearly shows that in example 3 with the optimal values of the main parameters of the claimed objects, the ratio α of energy consumption per unit of moisture removed is 1.5 times better than this ratio for known objects.

The lower and upper boundaries of the parameters reflected in the claims were obtained by statistical selection and generalization of experimental data, based on the condition that the goal is minimally achievable:
(α 1,02 at the lower boundary, example 1,
α = 1.03 at the upper boundary, example 2).

 As follows from the table, going beyond the lower and upper boundaries of the parameters makes it impossible to achieve the goal (α 0.99 when going beyond the lower border, example 4; α 0.98 when going beyond the upper border, example 5).

 With other options for the practical implementation of the declared objects, the goal was achieved when the parameter values were inside the declared boundaries (example 6), or did not exceed them (example 7).

 If at least one parameter exceeded the declared boundary, then even with the values of the remaining parameters within the declared limits, the goal was not achieved (example 8).

 Drying by the proposed method is carried out at low temperatures, which prevents the loss of nutrients in the prepared feed. In addition, the isolation of the process ensures the ecological purity of the process, and the declared objects can be used not only in agriculture, but also in chemical, pharmacological and other industries.

Claims (2)

1. The method of drying bulk materials, including heating the coolant, treating it with the drying mass in the process of moving it, cooling and drying the coolant, characterized in that before processing the drying mass is heated with a coolant that is previously compressed to a pressure of 0.15
0.29 MPa and heated to 410-460 K, and the heating is carried out with a parallel movement of the drying mass and coolant in one direction with a ratio of the speed of the coolant to the speed of the drying mass of 0.001 0.01, after which the coolant is cooled to a temperature whose ratio to the temperature of the coolant before heating the drying mass is in the range of 0.62 - 0.75, and its moisture content is reduced to a value whose ratio to the moisture content of the coolant before heating the drying mass is in the range of 0.76 1.0, then heat the desiccant is fed to the treatment of the drying mass, moving it towards the movement of the drying mass, the temperature of which is maintained within 295 335 K, and its moisture is brought to a value whose difference and the initial humidity in fractions of the latter lies within 0.1 1.0, and the coolant is filtered, compressed, heated and reused. 2. Installation for drying bulk materials, including a drying unit, made in the form of two bins for drying mass installed at different heights, the lower part of one of which is connected to the upper receiving part of the second hopper by the drying mass transport unit, which looks like a hollow screw enclosed in a pipe a shaft having pressurized ends at the ends of the pressurized unit, connected to the output of the heating medium heating unit, comprising filters, a compressor and a heater, characterized in that it is provided with additional drying units, in series connected to the main one in a closed system in which the second hopper of each subsequent node is the first hopper of the previous one, with the lower part of each hopper equipped with a metering device, and each drying unit equipped with a moisture separation unit made in the form of series-connected heat exchanger, turbine expander, dehumidifier and fan, wherein the screw pipe is connected to the input of the heat carrier heating unit, and the cavity of the screw shaft from the side of its output end is connected to the first input of the heat exchanger, the first output to through a turbine expander and a water separator is connected to the inlet of the heat exchanger, and the second outlet of the heat exchanger is connected to the inlet of the fan, the input of which is connected to the screw pipe, each hopper is equipped with inlet and outlet valves for the starting coolant, while the ratio of the volume of the cavity of the shaft of the screw to the volume of the cavity of the pipe is within

where d _{1 the} inner diameter of the shaft of the screw;
d ₂ outer diameter of the screw,
and the ratio of the volume of each hopper to the volume of the pipe cavity is in the range of 1.0-3.1.

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