RU130797U1 - INSTALLATION OF TWO-STAGE DRYING OF DISPERSED CAPILLARY-POROUS MATERIALS - Google Patents

Abstract

1. Installation for the implementation of two-stage drying of capillary-porous materials, which includes a device for intake from the environment and air supply for the first drying stage, a heater for heating it, an apparatus for the first drying stage, a device for supplying a drying gas to the first drying apparatus , apparatus for a second drying stage, a device for feeding wet material into a apparatus for a first stage, a heat exchanger for heating drying air of a second drying stage, a device for gas cleaning of exhaust dried gas of a first a drying stage with a fitting for the outlet of the purified spent drying air of the first drying stage, a gas duct for transferring the spent drying gas from the apparatus of the first drying stage to the gas cleaning system of the first drying stage, a device for unloading and supplying pre-dried material from the apparatus of the first drying stage to the receiving nozzle of the second apparatus drying stage, a device for unloading from the gas treatment system of the drying gas of the first drying stage of the captured dispersed material, the exhaust gas treatment system was dried of air of the second drying stage with fittings for entering and exiting exhaust drying air of the second drying stage, a device for collecting and supplying drying air of the second drying stage, characterized in that the apparatus includes a cooler for artificial cooling of the drying air of the second drying stage, a device for separating from the cooled drying air of the second stage of drying moisture in the form of condensate or ice, a gas duct connecting the outlet of the device for intake and supply of drying air for the second stage with

Description

The utility model can be used in chemical, microbiological, food, pharmaceutical, pulp and paper and other industries for drying various heat-sensitive dispersed materials having a capillary-porous structure.

The utility model can be used to obtain dry dispersed products during drying in spray drying apparatus when feeding raw materials in liquid form, such as condensed milk, fruit juices, etc.

When drying non-liquid, highly moist dispersed materials, such as wood chips, sawdust, granular organic fertilizers, etc., other types of dryers (for example, drum, vibrating, etc.) can be used as part of the installation.

A characteristic feature of drying materials with a capillary-porous structure is the presence of a second period of decreasing drying rate of materials, due to the difficulty of removing bound moisture from the structure of the material itself. To remove it, a significantly longer drying time is required than for the first drying period, when free moisture is removed. Therefore, it is advisable to dry such materials in two-stage plants.

Known drying plants for the most part operate using air from the surrounding space as a drying agent. The moisture content of air varies significantly depending on the weather and time of the year, often reaching a high value close to the state of full saturation. For example, even in summer at an ambient temperature of 25-35 ° C, the absolute moisture content can reach from 20 to 36 g per 1 cubic meter of absolutely dry air. In addition, with a sufficiently low moisture content of the outdoor air during the intake directly from the room, the air enters the drying unit with increased humidity, because In the production room, usually increased humidity, corresponding to sanitary and hygienic requirements. With a high initial moisture content of the drying air in the dryer in the second drying period, the removal of internal moisture from the structure of the material occurs with a significantly increased moisture content of the drying air. Therefore, the difference in moisture content in the drying air and on the surface of the dried material decreases (the moisture content gradient decreases) as the driving force of the drying process. As a result, in the apparatus of the second drying stage, the drying intensity decreases, the productivity decreases, which is a disadvantage of the process and existing drying plants.

The decrease in the drying intensity in the second stage in existing drying plants for this reason is compensated by an increase in the temperature gradient, preventing the temperature of the drying air at the end of the drying process from falling below a certain value, and accordingly, this is done by increasing the initial temperature of the drying agent at the entrance to the apparatus of the second drying stage .

In turn, this enhances the negative impact of high temperatures on thermosensitive drying products and leads to a fire hazard when drying organic materials.

It is known that the gradient of moisture transfer from the dried material to the drying agent can be increased by lowering its initial moisture content by condensation of the vapor contained therein by pre-cooling the drying agent and removing condensed moisture. Pre-cooling of drying air to 5-6 ° C reduces its moisture content to 4-5 g per 1 kg of absolutely dry air, and cooling to minus 14-15 ° C reduces the moisture content of air to almost zero, even with its one hundred percent initial relative humidity (see I-chart for humid air).

The intake and supply of drying air directly from the environment, often with a sufficiently high initial moisture content, reduces its moisture capacity and significantly reduces the growth potential of the unit’s productivity, both in the first and second stages of drying.

Therefore, as part of the inventive installation, it is proposed to use devices for the artificial cooling of drying gas, separating condensed moisture from water in the form of water or ice, as well as heat exchangers for pre-heating the air dried by cooling and heaters for heating to a predetermined initial drying temperature. The use of certain connection schemes for the apparatus of the installation will increase the productivity of the installation, reduce energy consumption and fire hazard.

Analogs

Consider several two-stage drying plants, which can be taken as analogues.

A two-stage drying of dairy products can be taken as an analogue, in which the condensed milk or other dairy products are spray-dried in the first-stage apparatus, and the material coming from the first-stage drying apparatus is dried in a convective vibratory dryer, which is the second-stage apparatus, to standard humidity (fig. 37, p. 89, fig. 38, p. 90, fig. 40, p. 92 from the book of N. N. Lipatov and V. D. Kharitonov. Powdered milk. M.: Light and food industry, 1981. - 164 s).

The decrease in the drying intensity in the apparatus of the second stage of drying as a result of the use of moisture-saturated air taken directly from the surrounding space (as is currently accepted in the industry) for drying leads to the need to use a special heater (heater) for preheating the drying air to a temperature of 120-150 ° C. At the same time, in order to achieve a standard moisture content of the product, it is necessary to maintain the temperature of the drying air and the product at the outlet of the apparatus of the second drying stage significantly higher than room temperature. Product deposits on the structural elements of the apparatuses of the first and second stages of drying, which, as a rule, occur during operation, at this temperature of drying air can lead to overheating of the product and the formation of foci of spontaneous combustion. The disadvantage is increased heat loss as a result of the fact that the flows of exhausted drying air after gas purification at a sufficiently high temperature are emitted into the atmosphere.

Thus, these plants are characterized by disadvantages such as large heat losses and, consequently, increased specific heat consumption per kg of evaporated and per kg of dry product produced in a moisture plant, as well as increased fire hazard.

Another analogue of the installation for drying wood chips in two stages can be considered the combined drying unit AKS-8 design Giprodrevprom (Fig. 11.10, p. 184, Handbook for the production of chipboards, - M. Publishing House of Forestry, 1990 .).

The disadvantage of this installation is that at an initial temperature of the drying agent of 500 ° C, its temperature at the outlet of the apparatus of the first stage of drying with usually unstable initial moisture content of the chips can vary within wide limits and reach 180 ° C. There is a fire hazard of the installation, the probability of which increases with a decrease in the initial moisture content of the chips. Such process conditions do not allow to maintain a constant productivity of the installation, which will increase the energy consumption for drying.

The disadvantage is the lack of input of fresh drying air for the second stage of drying. This leads to high moisture saturation of the drying agent as a result of evaporation of moisture during the drying process, which in turn requires maintaining a higher temperature of the spent drying agent at the outlet of the apparatus to obtain the standard moisture content of the final product in accordance with the equilibrium state diagram of wood. (P.V. Boldyrev. Wood Drying. A Practical Guide. PROFIX Publishing House: St. Petersburg, 2002, 160 p.). Similar equilibrium state diagrams of the drying agent and the material to be dried exist for drying other capillary-porous materials.

The fire hazard of the installation, if necessary, maintain the elevated temperature of the drying gas at the end of drying, when the product already has low humidity, is further enhanced. Therefore, such installations are equipped with autonomous fire fighting devices.

Another analogue of a two-stage installation for drying high-moisture bulk materials can be considered a two-stage drying unit “Butner-Schild-Haas AG”, in which the process of drying wood chips in two units is carried out. In the first unit, which is a cyclone dryer, free moisture is removed from the surface of the chip. In the second unit, where the residence time is much longer than in the first, the bound moisture is removed from the capillary-porous structure of the chip material (Fig. 57, p. 150, G.M.Shvartsman, D.A. Schedro. Production of wood-shaving plates, - M. Publishing house Forest industry, 1987).

The disadvantage of such a two-stage drying installation is fire hazard and large heat loss with exhaust gases and due to the fact that an independent firebox is used for the apparatus of the second drying stage and drying is carried out by flue gases with a sufficiently high temperature.

Prototype

The closest in its purpose, composition and technical essence to the claimed installation for drying capillary-porous products from starting liquid materials, is the installation of the company "Niro Atomizer" (Fig. 39, p.90 from the book of N.N. Lipatov and V.D. .Kharitonova. Powdered milk. M.: Light and food industry, 1981.-164 s).

This installation is adopted as a prototype. The prototype installation includes apparatuses of the first and second stages of drying, heaters for heating the drying air for these devices, gas cleaning systems for each stage of drying.

The prototype has all the disadvantages of the analogues listed above: high additional heat consumption for heating the air of the second stage of drying and significant losses of low-temperature heat that is released into the environment with exhausted drying air from the apparatus and gas treatment systems of the first and second stages of drying.

The disadvantage is the incomplete use of the productivity potential of the drying unit for evaporated moisture and the finished dry product. This is because drying gas (air) is often supplied to plants with a sufficiently high moisture content, moreover, it varies widely depending on atmospheric conditions. To increase the plant’s stable performance in terms of evaporated moisture and the finished product, it is necessary to maintain a higher process temperature at the outlet of the dryer.

Therefore, the negative effect of high temperatures at the end of drying on. product quality and fire hazard occurs.

In addition, the disadvantage is the need for additional energy costs for cooling the final product discharged from the apparatus of the second drying stage.

For the use of spent drying air saturated with moisture at a temperature of 80-90 ° С and even at 120 ° С there is no technological consumer within one installation, and utilization of such, as it is commonly called, low-temperature heat is not economically feasible. Therefore, a common drawback of the analogue and prototype plants is the large loss of low temperature heat with the exhausted drying air emitted into the environment.

The technical task of the claimed utility model is to create a drying installation, during operation of which the productivity of the installation is increased due to the fuller use of the moisture content of the drying air, the low-temperature heat of the exhausted drying air from the apparatuses of the first and second drying stages is utilized directly in the technological process at the same installation, eliminated or substantially reduced heat consumption for heating the drying air of the second stage of drying.

The technical task was also to obtain a dry product at the unit cooled to normal temperature during drying in the apparatus of the second stage of drying of the dry product without additional energy costs for its cooling. In addition, the objective was to reduce the fire hazard of the process and the negative impact of elevated drying temperatures on the quality of the dry product.

A technical solution to the problem is achieved by the fact that in the inventive installation, devices for the artificial cooling of drying air and a device for separating moisture condensed during ice cooling in the form of condensate or ice are used for preliminary drying of the drying air. Then, the drying air thus dried up is supplied to the heat exchanger before being fed to the drying apparatus, in which it is heated by utilizing the low-temperature heat of the exhausted drying air, and to the air heater, in which it is heated to the set initial drying temperature. Thanks to the preliminary drying thus performed and the temperature potential of the drying air being restored, the drying potential increases substantially, since increases the moisture capacity of the drying air.

Calculations using the diagram of the heat content of moist air show that the energy consumption for artificial cooling of drying air from a temperature of + 20 ° C to minus 15 ° C is two times lower than the cost of heating the drying air of the second stage of drying in a prototype installation from + 20 ° C to + 120 ° С (1st diagram of humid air, J. G. Peri. Handbook of a chemical engineer. T1. - Publishing house "Chemistry", Len. Department, 1969, 640 s). This leads to additional energy savings in the second stage of drying and to reduce the specific energy costs of the inventive installation.

In the cold period, the cost of artificial cooling of the drying air will significantly decrease, and in the frosty period they will be minimal, since the absolute humidity will be close to zero.

Additional heat consumption for cooling the drying air of the first drying stage taken from the environment from + 20 ° C to -15 ° C will be required in the warm period. However, they will be compensated by 50-70% by utilizing the heat of the spent drying air of the first drying stage with decreasing its temperature from 65 ° C at the outlet of the apparatus of the first drying stage to (+ 15 ° C) - (+ 30 ° C). Due to this, the temperature of the pre-chilled fresh drying air will be restored from a temperature of -15 ° C to (0- + 5) ° C. Further restoration of its temperature to an initial temperature of + 20 ° C can be carried out due to additional heat supplied from an external source, as well as due to additional heating in the heater of the first drying stage or by using the heat of the exhausted drying air of the second drying stage.

The additional heat costs for restoring the temperature of the drying air from (0 ÷ + 5) ° С to + 20 ° С will be compensated by an increase in plant productivity by 30% due to preliminary drying and an increase in the moisture capacity of the drying air.

As a result, in comparison with the prototype, the claimed installation will significantly increase productivity and significantly reduce the specific heat consumption per kg of evaporated moisture and dry product produced.

The installation of shut-off control devices (shut-off and control valves) on the gas duct and on the fittings in the connection diagram of the device for intake and supply of drying air, a device for artificial cooling of drying air and a device for separating moisture condensed during cooling is provided for. This allows you to change the ratio of the flows of drying air in the total flow of drying air supplied for heating to a heater or to a heat exchanger for preheating: - air taken directly from the atmosphere by utilizing the heat of the exhausted drying air and the air flow passing through the device for artificial cooling air. The ratio of these flows can be controlled, up to the complete replacement of the air cooled in the device for artificial cooling of air, air coming directly from the atmosphere. As a result, during a cold season, you can turn off the device for artificial cooling of air or reduce its productivity in the cold, which will significantly reduce energy costs for the production of artificial cold.

The use of a heat exchanger for preheating the drying air pre-dried by cooling makes it possible to utilize the low-temperature heat of the spent drying air from the apparatuses of both the second and first stages of drying.

Calculations show that the use of heat from the dried drying air for heating the cooled dried drying air for the apparatus of the second stage of drying for some parameters of the drying process allows you to abandon the additional cost of heat from an external heat source or to use them to a small extent.

Calculations show that the utilization in the heat exchanger of the low-temperature heat of the spent drying air from the apparatus of the first drying stage to heat the drying air of the second drying stage does not require heat consumption for heating it and thus can practically compensate for the energy consumption for obtaining artificial cold for drying by cooling the drying air of the second drying stages.

Under certain conditions, especially when modernizing existing drying plants with insufficient heat output of established standard heaters designed to heat drying air, it is advisable to supply additional heat from an external source to the preheater of the drying air cooled by cooling, for which purpose a fitting is provided at the inlet to the heat exchanger.

The proposed complete connection diagram of the apparatus of the apparatus allows drying the drying air supplied to both the apparatus of the first drying stage and the apparatus of the second drying stage by cooling, to utilize the heat of the exhausted drying air from these apparatuses, spending it on preheating the flows of the dried, dried, air-cooled air. At the same time, the unit's productivity in evaporated moisture will increase, due to the significantly increased moisture capacity of the drying air, due to its preliminary drying. The increased moisture capacity of air for the second stage of drying due to its preliminary drying by cooling makes it possible to obtain a dispersed product with standard humidity, which is in equilibrium with the state of the drying air at the outlet of the apparatus of the second stage of drying at a temperature close to the normal value (30-35 ° C) ) At the same time, the standard product humidity in analogous installations and in the prototype installation cannot be obtained at temperatures below 80-90 ° С.

NOTATION

1 - a device for taking from the environment and supplying drying air of the first drying stage, which may include an air intake filter, fan or gas blower;

2 - a supply gas duct connecting the inlet fitting of the device for artificial cooling of air of the first drying stage with a device for taking from the environment and supplying drying air of the first drying stage;

3 - locking regulating device;

4 - a device for artificial cooling of drying air of the first drying stage;

5 - fitting for entering the cooled air of the first drying stage into the device for artificial cooling of the drying air of the first drying stage;

6 - gas duct connecting the device for intake from the environment and supply of drying air for the first stage of drying with an air duct connecting the nozzle for leaving the cooled air from the device for artificial cooling of the drying air with a nozzle for entering the heated medium into the heat exchanger or into the air heater;

7 - fitting for the exit of chilled air from the device for artificial cooling of the drying air of the first drying stage;

8 - gas duct between the nozzle for leaving the cooled air from the device for artificial cooling of the drying gas of the first drying stage and the nozzle for entering the cooled supply gas into the device for separating moisture in the form of condensate or ice from the cooled air of the first drying stage;

9 - a fitting for entering the cooled feed gas into the device for separating moisture in the form of condensate or ice from the cooled air of the first drying stage;

10 - a device for separating moisture in the form of condensate or ice from the cooled air of the first drying stage;

11 - fitting for the exit of the cooled dried air of the first drying stage from the device for separating moisture from the cooled drying air of the first drying stage;

12 - a gas duct between the nozzle for leaving the cooled dried air of the first drying stage from the device for separating moisture from the cooled air of the first drying stage and the nozzle for entering the heated medium into the heat exchanger for preheating the air of the first drying stage or the nozzle for entering the heated medium into the air heater;

13 is a fitting for supplying drying air of a first drying stage to a heat exchanger for preheating drying air of a first drying stage;

14 - a heat exchanger for preheating the drying air dried by cooling of the first drying stage;

15 is a fitting for entering the coolant into the heat exchanger for preheating the drying air dried by cooling of the first drying stage;

16 - fitting for supplying coolant from an external additional heat source to the fitting for entering the coolant into the heat exchanger for preheating the drying air dried by cooling of the first drying stage;

17 - gas duct between the nozzle for supplying the coolant to the heat exchanger for preheating the air of the first drying stage and the nozzle for the outlet of the spent drying purified air of the second drying stage from the gas purification system of the second drying stage;

18 - fitting for the outlet of the heated medium (drying air) from the heat exchanger for preheating the air of the first drying stage;

19 - heater fitting for entering the heated air of the first drying stage;

20 - air heater for the main heating of the air of the first drying stage;

21 - a device for supplying drying gas to the apparatus of the first drying stage;

22 - a device for supplying wet material to the apparatus of the first drying stage;

23 - apparatus of the first stage of drying;

24 - fitting for the outlet of the spent drying purified air of the second drying stage and the gas treatment system of the second drying stage;

25 is a system for gas treatment of spent drying air of the second drying stage, which may include cyclones, filters, other gas treatment equipment, fans or gas blowers;

26 - fitting for entering the exhausted drying air of the second drying stage into the gas purification system of the second drying stage;

27 — a gas duct between a nozzle for exhausting dried air from the apparatus of the second drying stage and a nozzle for entering the exhaust drying air of the second drying stage into the gas purification system of the second drying stage;

28 - fitting for the outlet of the spent drying air from the apparatus of the second stage of drying;

29 - apparatus of the second stage of drying;

30 - a device for unloading a dry product from the apparatus of the second stage of drying;

31 - fitting of the apparatus of the second drying stage for receiving the dried material after the first drying stage;

32 - a device for unloading pre-dried material from the apparatus of the first drying stage into the apparatus of the second drying stage;

33 - fitting for entering the coolant in the apparatus of the second stage of drying;

34 - flue between the nozzle for the exit of the heated drying air of the second drying stage from the heat exchanger for heating the drying air of the second drying stage and the nozzle for entering the coolant into the apparatus of the second drying stage;

35 - a device for unloading from the gas treatment system of the first stage of drying of the captured dispersed material;

36 is a system for gas treatment of spent drying air of the first drying stage, which may include cyclones, filters, other gas treatment equipment, fans or gas blowers;

37 - flue for transmitting spent drying air from the apparatus of the first drying stage to the gas treatment system of the first drying stage;

38 - fitting for the outlet of the heated drying air of the second drying stage from the heat exchanger of the second drying stage;

39. - a heat exchanger for heating the drying air of the second drying stage;

40 - a gas duct connecting the fitting of the gas cleaning system for the outlet of the purified drying air of the first drying stage with a fitting for entering the coolant into the heat exchanger of the second drying stage;

41 - fitting for the outlet of the spent purified drying air of the first drying stage from the gas treatment system of the first drying stage;

42 - a fitting for supplying a heat carrier from an additional external heat source to a heat exchanger for heating the drying air of the second drying stage;

43 - fitting for entering the coolant into the heat exchanger for heating the drying air of the second drying stage;

44 is a fitting for entering a second drying stage of heated drying-dried drying air into a heat exchanger of a second drying stage;

45 - duct between the nozzle for draining the cooled cooled air from the device for separating moisture from the cooled air of the second drying stage and the nozzle for entering the coolant into the heat exchanger to heat the drying air of the second drying stage;

46 - fitting for the exit of the cooled dried air from the device for separating moisture from the dried cooled air of the second stage of drying;

47 - a device for separating moisture in the form of condensate or ice from the cooled drying air of the second drying stage;

48 - fitting for entering the cooled drying air of the second drying stage into a device for separating moisture from the dried cooled air of the second drying stage;

49 - duct between the nozzle for entering the cooled drying air of the second drying stage into the device for separating moisture from the dried cooled air of the second drying stage and the nozzle for leaving the cooled air from the device for artificial cooling of the drying air of the second drying stage;

50 - duct connecting the duct between the outlet for drying air of the second drying stage from the device for intake and supply of drying air of the second drying stage and the nozzle for entering the drying air into the device for artificially cooling the drying air of the second drying stage with an air duct connecting the nozzle for the exit of the cooled air from the device for artificial cooling of air of the second stage of drying with a fitting for entering the cooled drying second stage of drying into a device for separating moisture from cooling the expected air of the second drying stage;

51 - fitting for the exit of the cooled drying air from the device for artificial cooling of air of the second stage of drying;

52 - a device for artificial cooling of drying air of the second stage of drying;

53 - fitting for supplying the cooled drying air to the device for artificial cooling of air of the second stage of drying;

54 - gas duct between the nozzle for the exit of drying air of the second drying stage from the device for intake and supply of drying air of the second drying stage and the nozzle for entering the drying air into the device for artificial cooling of the drying air of the second drying stage;

55 - supply nozzle for the exit of drying air of the second stage of drying from the device for intake and supply of drying air of the second stage of drying;

56 - a device for taking from the environment and supplying drying air for the second stage of drying, which may include an air intake filter, fan or gas blower;

57 is a gas duct connecting the fitting for the outlet of the purified drying air from the gas cleaning system of the first drying stage to the fitting for supplying a heat carrier to the heat exchanger for preheating the drying air of the first drying stage.

Novelty

In the installation according to the claimed utility model, the new is that: the unit includes a cooler (52) for the artificial cooling of the drying air of the second stage of drying, a device (47) for separating moisture from the cooled drying air of the second stage in the form of condensate or ice, gas duct (54) connecting the outlet nozzle (55) of the device (56) for intake and supply of drying air for the second drying stage with a fitting (53) for entering the drying air into the device (52) for the artificial cooling of the drying air of the second drying stage moreover, the nozzle (51) for leaving the cooled air from the device (52) for the artificial cooling of the drying air of the second stage of drying is connected via a gas duct (49) to the nozzle (48) for supplying the cooled drying air of the second stage of drying to the device (47) for separation moisture in the form of condensate or ice from the cooled drying air of the second drying stage, and its nozzle (46) for exiting the cooled dried air is connected via a gas duct (45) to the nozzle (44) for entering the dried cooled air of the second drying stage into eploobmennik (39) for heating the drying air in the second drying step;

- a gas duct (54) connecting the outlet nozzle (55) of the device (56) for taking from the environment and supplying drying air for the second drying stage with a fitting (53) for entering the drying air into the device (52) for the artificial cooling of the second stage drying air drying, connected by means of a duct (50) with a duct (49) connecting the nozzle (51) for the exit of chilled air from the cooler (52) for the artificial cooling of the drying air of the second stage of drying with a nozzle (48) for supplying cooled air to the device (47) for separation GI in the form of condensate or ice from the cooled drying air of the second stage of drying of the second stage of drying, moreover, on the fittings (53) and (51) for the inlet and outlet of the cooled drying air of the device (52) for artificial cooling of air of the second stage of drying and in the duct ( 50) connecting the duct (54) between the nozzle (55) for the outlet of the drying air of the device (56) for the intake and supply of drying air of the second drying stage and the nozzle (53) for the input of the drying air into the device (52) for the artificial cooling of the drying air of the second stud and drying with an air duct (49) between the nozzle (48) for entering the device (47) for separating moisture from the cooled drying air of the second drying stage and the nozzle (51) for leaving the cooled air from the device (52) for artificial cooling of the air of the second drying stage , locking and control devices are installed (3);

- the unit includes a device (4) for artificial cooling of air of the first drying stage, a device (10) for separating moisture from condensed or ice from the first drying air of the first stage, a heat exchanger (14) for preheating the cooled drying air of the first drying stage , the nozzle (5) for entering the cooled air of the device (4) for artificial cooling of the air of the first drying stage is connected by means of a supply duct (2) to the device (1) for intake and supply of drying air of the first st drying step, the nozzle (7) for the outlet of the cooled air through the gas duct (8) is connected to the nozzle (9) for entering the cooled air of the first drying stage into the device (10) for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, and its nozzle (11) for leaving the cooled dried air through a gas duct (12) is connected to the nozzle (19) for entering the heated medium into the air heater (20) for completely heating the air of the first drying stage or for preheating it is connected to the nozzle (9) for entering heated cf food in the heat exchanger (10), installed in front of the heater (20);

- on the fittings (5) and (7) of the device (4) for the artificial cooling of the drying air of the first drying stage for the inlet and outlet of the cooled air and on the gas duct (6) connecting the supply duct (2) of the device (1) for the intake and supply of drying air for the first stage of drying with a duct (8) connecting the nozzle (7) for leaving the cooled air from the device for artificial cooling of air of the first stage of drying with a nozzle (9) for entering the cooled air of the first stage of drying into the device (10) for heating the drying air first stage of drying , locking and control devices are installed (3);

- the nozzle (41) for the exhaust of dried drying gas from the system (36) for gas treatment of the first drying stage is connected via a gas duct (57) to the nozzle (15) for entering the coolant into the heat exchanger (14) for preheating the cooled drying air of the first drying stage;

- a fitting (24) for exiting the cleaned exhaust drying air from the gas treatment system (25) of the second drying stage is connected to a fitting (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a gas duct (17), which has a fitting (16) for supplying coolant to it from an additional heat source;

- the fitting (41) of the system (36) for gas treatment of the spent drying gas of the first drying stage is connected to the fitting (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a duct (57), which may have a fitting (16) for supplying coolant to it from an additional heat source;

- the nozzle (41) of the gas treatment system for exhausting the exhaust drying gas of the first drying stage is connected to the nozzle (43) for entering the coolant into the heat exchanger (39) for heating the cooled drying air of the second drying stage by means of a duct (40) that has a nozzle ( 42) to supply heat from an additional source.

The utility model is illustrated by the following figures:

Figure 1. Installation diagram using a device for artificial cooling of drying air of the second drying stage.

Figure 2. Installation diagram using a device for artificial cooling of drying air of the second drying stage and shut-off and regulating devices for switching the flows of drying air of the second drying stage.

Figure 3. Installation diagram using devices for artificial cooling of drying air of the second and first stages of drying.

Figure 4. Installation diagram using devices for artificial cooling of drying air of the second and first stages of drying and a heat exchanger for preheating the drying air of the first stage of drying.

Figure 5. Installation diagram using devices for artificial cooling of drying air of the second and first stages of drying, a heat exchanger for preheating drying air of the first stage of drying and shut-off and regulating devices for switching the flows of drying air of the first stage * drying.

6. Installation diagram using devices for artificial cooling of drying air of the second and first stages of drying, a heat exchanger for preheating the drying air of the first stage of drying and shut-off and regulating devices for switching the flows of drying air of the first and second stages of drying.

7. General installation scheme with a set of features of a technical solution.

Static installation description

Figure 1.

The installation comprises a device (1) for taking from the environment and supplying air for the first drying stage, a heater (20) for heating it, an apparatus for the first drying stage (23), a device (21) for supplying the drying gas to the first drying stage, the second apparatus drying stages (29), a device (22) for supplying wet material to the apparatus of the first stage, a heat exchanger (39) for heating the drying air of the second drying stage, a device (36) for gas cleaning of the exhaust drying gas of the first drying stage with a nozzle (41) to exit refined spent su of fresh air of the first drying stage, a gas duct (6) connecting the supply gas duct (2) from the device (1) for intake and supply of drying air with a fitting (16) for the inlet of the heated medium of the air heater (19), the gas duct (37) for transferring the spent drying gas from the apparatus of the first drying stage (23) to the gas treatment system (39) of the first drying stage, a device (32) for unloading and supplying pre-dried material from the apparatus (23) of the first drying stage to the receiving nozzle (31) of the apparatus of the second drying stage, device (35) for discharging from a sushi gas treatment system sludge gas of the first drying stage of the captured dispersed material, a gas cleaning system (25) of the spent drying air of the second drying stage with fittings (26) and (24) for entering and leaving the exhausted drying air of the second drying stage, a device (56) for collecting and supplying drying air the second stage of drying with a fitting (55) for supplying drying air to the unit, a device (52) for the artificial cooling of the drying air of the second stage of drying, a gas duct (54) connecting the nozzle (55) for supplying drying air to the unit, a device VA (56) for intake and supply of drying air for the second drying stage with a fitting (53) for entering the drying air into the device (52) for the artificial cooling of the drying air of the second drying stage, a device (47) for separating the second drying stage from the cooled drying air moisture in the form of condensate or ice, a nozzle (51) for leaving the cooled air from the device (52) for the artificial cooling of the drying air of the second drying stage, which is connected via a duct (49) to the nozzle (48) for supplying the cooled drying air the ear of the second stage of drying into the device (47) for separating moisture in the form of condensate or ice from the cooled drying air of the second stage of drying, the nozzle (46) of which is connected via a duct (45) to the nozzle (44) for the entry of the dried cooled air of the second drying stage to a heat exchanger (39) for heating the drying air of the second drying stage.

Figure 2.

In addition to the devices and process connections shown in FIG. 1 using air ducts and fittings in the installation, on the fittings (53) and (51) of the device (52) for the inlet and outlet of the cooled drying air of the second stage of drying and in the duct (50) connecting the duct (54) between the nozzle (55) for the exit of drying air from the device (56) for intake and supply of drying air of the second stage of drying and the nozzle (53) for the entrance of drying air into the device (52) for cooling the drying air of the second stage of drying with an air duct (49) between w by user (48) for entering the cooled drying air of the second drying stage into the device (47) for separating moisture from the cooled drying air of the second drying stage and by a fitting (51) for leaving the cooled air from the device (52) of the air of the second drying stage, shut-off and control valves are installed devices (3).

Figure 3.

In addition to the devices and process connections shown in FIG. 1 using air ducts and fittings, the installation includes a device (4) for artificially cooling the air of the first drying stage, a device (10) for separating moisture from the first drying stage of cooled moisture from the cooled drying air in the form of condensate or ice, nozzle (5) for entering cooled air into the device (4) for artificial cooling of air of the first drying stage, which is connected by means of a supply duct (2) to a device (1) for intake and supply of drying air ha of the first stage of drying, the nozzle (7) for leaving the cooled air from the device (4) for artificial cooling of the air of the first stage of drying by means of a duct (8) is connected to the nozzle (9) for entering the cooled air of the first stage of drying into the device (10) for separation moisture in the form of condensate or ice from the cooled air of the first drying stage, and its nozzle (11) for the outlet of the cooled dried air through a gas duct (12) is connected to the nozzle (19) for entering the heated medium into the air heater (20) for heating the air of the first drying stage .

Figure 4.

In addition to the devices and process connections shown in FIG. 3 using air ducts and fittings, the installation includes a heat exchanger (14) for preheating the drying air of the first drying stage, a nozzle (7) for leaving the cooled air from the device (4) for artificial air cooling the first stage of drying by means of a duct (8) connected to the nozzle (9) for entering the cooled air of the first stage of drying into the device (10) for separating moisture in the form of condensate or ice from the cooled air of the first stage of su ki, its fitting (11) for the outlet of the cooled dried air through a gas duct (12) connected to the fitting with a fitting (13) for entering the heated medium into the heat exchanger (14), the fitting of which (18) for the outlet of the heated medium connected to the fitting (19) ) to enter the heated medium into the air heater (20).

Figure 5.

In addition to the devices and process connections shown in FIG. 4 using air ducts and fittings, on the fittings (5) and (7) for the inlet and outlet of the cooled air of the device (4) for the artificial cooling of the drying air of the first drying stage and on the gas duct (6), connecting the supply gas duct (2) of the device (1) for intake and supply of drying air for the first drying stage with a gas duct (8) connecting the nozzle (7) for leaving the cooled air from the device (4) for artificial cooling of the air of the first drying stage with the nozzle ( 9) to enter the wasp The shut-off-regulating devices (3) are installed in the chilled air of the first stage of drying in the device (10) for separating moisture in the form of condensate or ice from the chilled air of the first stage of drying.

6.

In addition to the devices and process connections shown in FIG. 5 using air ducts and fittings, on the fittings (53) and (51) for the inlet and outlet of the cooled drying air of the device (52) for the artificial cooling of the drying air of the second stage of drying and in the duct (50) connecting the duct (54) between the nozzle (55) for the outlet of the drying air of the device (56) for intake and supply of drying air of the second drying stage and the nozzle (53) for the entrance of the drying air into the device (52) for the artificial cooling of the drying air of the second st drying step with an air duct (49) between the nozzle (48) for entering the device (47) for separating moisture from the cooled drying air of the second drying stage and the nozzle (51) for leaving the cooled air from the device (52) for artificial cooling of the second drying stage air locking and control devices are installed (3).

In addition to the main hardware and technology circuits (Fig.1-6)

the following options for the composition of the installation are given, which, depending on the conditions of application of the installation, allow solving the technical problem of the utility model:

the outlet nozzle (41) of the system (36) for gas treatment of the spent drying gas of the first drying stage is connected by means of a gas duct (57) to the nozzle (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage;

- a fitting (24) for exiting the cleaned exhaust drying air from the gas treatment system (25) of the second drying stage is connected to a fitting (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a gas duct (17), which has a fitting (16) for supplying coolant to it from an additional heat source;

- the fitting (41) of the system (36) for gas treatment of the spent drying gas of the first drying stage is connected to the fitting (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a duct (57), which may have a fitting (16) for supplying coolant to it from an additional heat source;

- the nozzle (41) of the gas treatment system for exhausting the exhaust drying gas of the first drying stage is connected to the nozzle (43) for entering the coolant into the heat exchanger (39) for heating the cooled drying air of the second drying stage by means of a duct (40) that has a nozzle ( 42) to supply heat from an additional source.

The composition of the installation, taking into account the basic schemes and additions to them, is given in the general hardware and technological scheme of Fig. 7 with a full range of features of a technical solution of a utility model.

The general hardware and technological scheme contains all the options for technological connections between the apparatus devices, in which, depending on the operating conditions of the application, the technical task of the utility model is solved — to create a two-stage plant for drying capillary-porous dispersed materials with improved technical and economic indicators:

- increased plant productivity due to the more complete use of the moisture capacity potential of drying air, eliminated or significantly reduced heat costs for heating the drying air of the second drying stage, utilized directly in the technological process at the same installation low-temperature heat of exhausted drying air from the apparatuses of the first and second drying stages, a dry product cooled to normal temperature was obtained without additional energy costs for its cooling, the negative effect was reduced the high temperature of the drying agent on the quality of the product and the fire hazard of the process at the installation.

7.

The installation comprises a device (1) for taking from the environment and supplying air for the first drying stage, a heater (20) for heating it, an apparatus for the first drying stage (23), a device (21) for supplying the drying gas to the first drying stage, the second apparatus drying stages (29), a device (22) for supplying wet material to the apparatus of the first stage, a heat exchanger (39) for heating the drying air of the second drying stage, a gas treatment system (36) for exhausted drying gas of the first drying stage with a fitting (41) for the outlet of the purified waste dryer about the air of the first drying stage, the gas duct (6) connecting the device (1) for intake from the environment and supplying drying air for the first drying stage with the air duct (8) connecting the nozzle (7) for the exit of the cooled air from the device (4) for artificial cooling of the drying air with a fitting (9) for entering the cooled air into the device (10) for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, a supply duct (2) for supplying drying air from the device (1) for intake and dryer supply spirit with a fitting (19) for entering the heated medium of the air heater (20), a gas duct (37) for transferring the spent drying gas from the apparatus of the first drying stage (23) to the gas cleaning system (39) of the first drying stage, a device (32) for unloading and supplying pre-dried material from the apparatus (23) of the first drying stage to the receiving nozzle (31) of the apparatus of the second drying stage, a device (35) for discharging from the gas treatment system of the drying gas of the first drying stage of the trapped dispersed material, the gas purification system (25) of the spent drying air stage of drying with nozzles (26) and (24) for entering and exiting exhaust drying air of the second drying stage, device (56) for collecting and supplying drying air of the second drying stage with a nozzle (55) for supplying drying air to the installation, device ( 52) for the artificial cooling of the drying air of the second drying stage, a gas duct (54) connecting the supply nozzle (55) for supplying the drying air to the installation, devices (56) for intake and supply of drying air for the second drying stage with a fitting (53) for entry drying air to cool ice (52) for the artificial cooling of the drying air of the second drying stage, a device (47) for separating moisture from the second drying stage of the moisture in the form of condensate or ice, a fitting (51) for leaving the cooled air from the device (52) for the artificial cooling of the drying the air of the second drying stage, which is connected by means of a duct (49) with a fitting (48) for supplying cooled drying air of the second drying stage to the device (47) for separating moisture in the form of condensate or ice from the cooled drying air the second drying stage, the nozzle (46) of which for the outlet of the cooled dried air is connected via a gas duct (45) to the nozzle (44) for entering the dried cooled air of the second drying stage into the heat exchanger (39) for heating the drying air of the second drying stage,

on the fittings (53) and (51) for the inlet and outlet of the cooled drying air of the second drying stage of the device (52) for the artificial cooling of the drying air of the second drying stage and on the duct (50) connecting the duct (54) between the fitting (55) for the outlet drying air from the device (56) for intake and supply of drying air of the second drying stage and a nozzle (53) for entering the drying air into the device (52) for artificially cooling the drying air of the second drying stage with an air duct (49) between the nozzle (48) for entering refrigerated dryer air of the second stage of drying in the device (47) for separating moisture from the cooled drying air of the second stage of drying and a fitting (51) for the outlet of the cooled air from the device (52) for the artificial cooling of the drying air of the second stage of drying, shut-off and control devices are installed (3) ;

there is a device (4) for artificial cooling of air of the first drying stage, a device (10) for separating moisture from condensed or ice from the first drying stage of cooled air, a nozzle (5) for entering cooled air into a device (4) for artificial cooling of air the first drying stage, which is connected by means of a gas duct (2) to the device (1) for intake and supply of drying air of the first drying stage, a fitting (7) for the exit of chilled air from the device (4) for artificial cooling of the first stage air drying by means of a gas duct (8) is connected to a nozzle (9) for entering the cooled air of the first drying stage into a device (10) for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, and its nozzle (11) for leaving the cooled dried air by means of a gas duct (12) connected to the fitting (19) for entering the heated medium into the air heater (20) for heating the air of the first drying stage,

there is a heat exchanger (14) for preheating the drying air of the first drying stage, a fitting (7) for leaving the cooled air from the device (4) for artificially cooling the air of the first drying stage by means of a duct (8) connected to the fitting (9) for entering the first cooled air the drying stage in the device (10) for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, its nozzle (11) for the outlet of the cooled dried air through a duct (12) connected to the nozzle (13) for inlet grevaemoy medium in the heat exchanger (14), which nipple (18) to exit the heated medium connected to the fitting (19) to enter the heated medium in the heater (20)

on the nozzles (5) and (7) for the inlet and outlet of the cooled air of the device (4) for the artificial cooling of the drying air of the first drying stage and on the gas duct (6) connecting the supply nozzle (2) of the device (1) for intake and supply of drying air for the first drying stage with a gas duct (8) connecting the nozzle (7) for leaving the cooled air from the device (4) for the artificial cooling of the drying air of the first drying stage with a fitting (9) for entering the dried cooled air of the first drying stage into the device (10) to separate moisture in the form of ndensata ice or cooled air from the first drying stage are mounted locking-regulating device (3),

on the fittings (53) and (51) for the inlet and outlet of the cooled drying air of the second drying stage of the device (52) for the artificial cooling of the drying air of the second drying stage and on the duct (50) connecting the duct (54) between the fitting (55) for the outlet drying air of the device (56) for intake and supply of drying air of the second drying stage and a fitting (53) for entering the drying air into the device (52) for artificially cooling the drying air of the second drying stage with an air duct (49) between the fitting (48) for entering separation device (47) moisture from the cooled drying air of the second stage of drying and a fitting (51) for leaving the cooled air from the device (52) for the artificial cooling of air of the second stage of drying, shut-off and control devices are installed (3),

the outlet nozzle (41) of the system (36) for gas treatment of the spent drying gas of the first drying stage is connected via a gas duct (57) to the nozzle (15) for entering the coolant into the heat exchanger (14) for preheating the cooled drying air of the first drying stage,

the nozzle (24) for the outlet of the purified spent drying air from the gas treatment system (25) of the second drying stage is connected to the nozzle (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a duct (17) a fitting (16) for supplying coolant to it from an additional heat source,

the nozzle (41) for exiting the system (36) for gas purification of the spent drying air of the first drying stage is connected to the fitting (15) for entering the coolant into the heat exchanger (14) for preheating the cooled drying air of the first drying stage by means of a duct (57) have a fitting (16) for supplying coolant to it from an additional heat source,

the nozzle (41) of the gas purification system for exhausting the exhaust drying gas of the first drying stage is connected to the nozzle (43) for entering the coolant into the heat exchanger (39) for heating the cooled drying air of the second drying stage by means of a duct (40) that has a nozzle (42) ) to supply heat from an additional source.

Installation procedure

In the general case, any drying gas (except water vapor and vapors of other substances that could be used as a drying agent), and in the most common case air, enters a device for the artificial cooling of drying air. As such a cooler for cooling air to sub-zero temperatures, one of the types of refrigeration machines widely used in industry can be used (Kurylev E.S. Gerasimov N.A. Refrigeration units. - M.L .: Mashgiz, 1961. -380 from).

For preliminary cooling of air to low positive temperatures, a device for artificial cooling of air when using water from wells can be used.

The air is cooled in the cooler to a temperature of from plus 5 ° C to minus 14-15 ° C (further lowering of the air temperature is not economically feasible, since even at this temperature the air moisture content is close to zero). Then, in the end, utilizing the low-temperature heat of the spent drying gas and, if necessary, spending additional heat on heating the fresh drying gas, previously drained by cooling before drying, it is possible to solve all the technical problems of the utility model listed above.

Description to the circuit of Fig. 1. Fresh drying air of the second drying stage through the device (56) for intake from the environment enters the device (52) for the artificial cooling of the drying air of the second drying stage. After cooling, air enters the device (47) for drying the drying air of the second stage of drying, where moisture is separated from the air in the form of condensate or ice. Next, the dried cooled air of the second drying stage enters the heat exchanger (39) and, after heating to a predetermined initial temperature, is sent to the apparatus of the second drying stage. Therefore, the drying air will have an initial humidity close to zero, and, accordingly, a high moisture capacity in comparison with the installation of the prototype, on which there is no device for cooling the air and a device for separating condensed moisture. Thus, in order to achieve the same or greater efficiency in evaporated moisture, the apparatus (29) of the second drying stage can be supplied with air pre-dried by cooling at a lower temperature than in the prototype installation.

Calculations show that the standard humidity of dry milk products is 3.5-4.5% on a prototype installation with a spray drying apparatus as the apparatus of the first stage of drying by supplying untreated air to the apparatus of the second stage of drying can be obtained at a final temperature of 80-90 ° C at the exit of the apparatus of the second stage of drying. At the same time, when air is supplied to the apparatus of the second stage of drying, dried by cooling in the inventive installation (Fig. 1), the standard humidity of the product can be obtained at the outlet and apparatus of the second stage of drying at a final process temperature of 30-35 ° C.

When two-stage drying on the inventive installation, the quality of particularly heat-sensitive products can be improved by reducing the effect of high temperature from the drying air.

Description to the scheme of figure 2. The drying air for the second drying stage, coming through the device (56) for air intake from the surrounding space, can be supplied through the device (52) for the artificial cooling of the drying air, both through the duct 54 and through the parallel duct 50.

Thanks to the locking and regulating devices (3) installed on these gas ducts and on the fitting (51) for the exit of the cooled drying air from the device (52) for the artificial cooling of air of the second stage of drying, it is possible to change the flow rate ratio of the drying air taken directly from the atmosphere and the flow passing through the device (52) for artificial cooling of air of the second stage of drying.

By adjusting their ratio, up to the complete replacement of the air cooled in the device (52) for the artificial cooling of the drying air of the second stage of drying with air from the atmosphere, it is possible to significantly reduce the energy cost of producing artificial cold in the cold season.

As well as in the installation of FIG. 1, in the installation according to the scheme of FIG. 2, in addition to all the factors of the technical task listed above, the cost of obtaining cold in the cold season is reduced.

Description to the scheme of figure 3, in addition to the description of the scheme of figure 1. Fresh drying air of the first drying stage from the device (1) for intake of air from the environment enters the device (4) for artificially cooling the drying air of the first drying stage, then passes the device (10) for separating condensed moisture and after heating in the heater (20) enters the apparatus (23) of the first drying stage through the device (21) for supplying the drying gas of the first drying stage to the apparatus.

Since the apparatus of the first drying stage evaporates up to 90% of the total capacity of the two-stage plants and uses an amount of air an order of magnitude larger than for the second drying stage, drying by cooling the drying air of the first drying stage, by analogy with the second drying stage, will lead to an even greater effect of productivity growth due to a fuller use of the potential of increased moisture capacity of pre-dried drying air. In combination with dehumidification by cooling the air of the second stage of drying in the apparatus (4) and (10), the specific heat consumption per kg of evaporated moisture and the fire hazard of the installation are also reduced.

Description to the circuit of FIG. A in addition to the circuit of FIG. 3. The cooled dried air of the first stage of drying before being fed to the heater (20) for the second stage of drying is preheated in a heat exchanger (14), which has a fitting (15) for supplying heat from an external source. This addition is of significant importance when introducing a technical solution in existing modernized plants, if a standard air heater at the plant is not able to provide heating of the cooled drying air of the first drying stage to a predetermined initial temperature before being fed to the apparatus of the first drying stage (23).

Description to the diagram of FIG. 5 in addition to the diagram of FIG. 4. Drying air for the first stage of drying, coming through the device (1) for air intake from the surrounding space, can be supplied to the cooler (4) through the duct (2), and through the parallel duct (6).

Thanks to the locking and regulating devices (3) installed on these flues and on the nozzle (7) for the exit of the cooled drying air from the device (4) for the artificial cooling of the air of the second stage of drying, it is possible to change the ratio of the flow rates passed through the device (4) for artificial cooling of the drying air and the flow of drying air taken directly from the atmosphere and transmitted through the duct (6).

By adjusting their ratio, up to the complete replacement in the cold period of the air cooled in the device (4) for the artificial cooling of the drying air of the second stage of drying with air from the atmosphere, it is possible to significantly reduce the energy cost of producing artificial cold. Moreover, due to the multiple excesses of the consumption of drying air in the first stage of drying compared with the second stage, the increase in plant productivity and a decrease in the specific heat consumption will be even more significant than the use of a similar scheme when supplying cooled dried air for the second stage of drying (Fig. 1 ) The fire hazard of the installation is reduced, because at the outlet of the first stage apparatus, the temperature of the drying air can be reduced.

Description to the diagram of FIG. 6 in addition to the diagram of FIG. 5. Drying air for the second drying stage, coming through the device (56) for air intake from the surrounding space, can be supplied to the device (52) for the artificial cooling of the drying air, both through the duct (54) and through the parallel duct (50).

In the same way, thanks to the locking and regulating devices (3) installed on these flues and on the fitting (5) for the exit of the cooled drying air from the device (52) for the artificial cooling of the air of the second stage of drying, it is possible to change the flow rate ratio of the drying air taken directly from the environment, and the flow passing through the device (52) for artificial cooling of air.

Thus, in such a plant, it is possible, using natural cold, to reduce the energy costs of producing artificial cold in the cold periods of the year, both for drying the drying air with cold in the first and second stages of drying.

Description of the scheme of Fig.7

in addition to the description of the schemes of figures 1-6:

- the spent drying air of the first drying stage from the nozzle (4) of the gas treatment system for the utilization of low-temperature heat is transferred to the heat exchanger (39) as a heat carrier and is used to heat the drying air dried by cooling of the second drying stage; if this heat is insufficient, to heat the drying air of the second stage of drying, additional heat is supplied from an external source through the fitting (42) to the gas duct (40);

in addition to the description of the schemes of figures 4, 5, 6:

- the spent purified drying air of the second drying stage comes from the nozzle (24) of the second stage gas treatment system through the gas duct (17) to the nozzle (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage; if this heat is insufficient for heating the drying air of the first drying stage, an additional coolant is supplied from an extraneous source through a fitting (16) into a fitting (15) for supplying a heat transfer agent to a heat exchanger (14);

- the exhausted drying air of the first drying stage from the nozzle (41) of the gas purification system enters through the gas duct (57) to utilize the low-temperature heat to the heat exchanger (14) as a heat carrier and is used to heat the drying air dried by cooling of the first drying stage; if this heat is insufficient for heating the drying air of the first drying stage, an additional coolant is supplied from an extraneous source through a fitting (16) into a fitting (15) for supplying a heat transfer agent to a heat exchanger (14);

- the spent purified drying air of the second drying stage comes from the nozzle (24) of the second stage gas treatment system through the gas duct (17) to the nozzle (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage, the exhausted drying air of the first stage of drying from the nozzle (41) of the gas treatment system (36) enters through the gas duct (57) for the utilization of low-temperature heat into the heat exchanger (14) as a heat carrier and is used to heat the dry land cooled by cooling flax air of the first stage of drying; if this heat is insufficient for heating the drying air of the first stage of drying, an additional coolant is supplied from an external source into the fitting (15) for supplying the coolant of the heat exchanger (14);

- the spent purified drying air of the second drying stage comes from the nozzle (24) of the second stage gas treatment system through the gas duct (17) to the nozzle (15) for entering the heat carrier into the heat exchanger (14) for preheating the cooled drying air of the first drying stage, the exhausted drying air of the first drying stage from the nozzle (41) of the gas purification system (3) is supplied through a gas duct (57) for the utilization of low-temperature heat to the heat exchanger (14) as a heat carrier and is used to heat the dry land cooled by cooling nogo air first drying step, wherein, the exhaust drying air from the first drying stage nozzle (41) of the system (36) for recycling gas purification enters low temperature heat exchanger (39) as a coolant and is used for heating the drying air dried by cooling the second drying step; if this heat is insufficient for heating the drying air of the second drying stage, additional heat is supplied from an external source through a fitting (42) through a gas duct (40), a fitting (43) for supplying a heat carrier to a heat exchanger (39); if this heat is insufficient for heating the drying air of the first stage of drying, an additional coolant is supplied from an external source through a fitting (16) to the flue (57).

Utility Model Execution Examples

Comparison of the estimated technical and economic indicators of two-stage drying for installation of the prototype and the claimed installation.

1. A two-stage installation in the form of two sequentially located drum dryers for drying chips.

The technical and economic indicators were calculated using the first stage of drying of the drying air at the inlet of the apparatus at the initial temperature of the drying air of 287-575 ° С. Drying modes using:

- atmospheric air taken from the external environment at a temperature of + 25 ° C (without drying by cooling);

- drying air previously drained by cooling to + 5 ° C and to minus 15 ° C.

The transition to the use of air dried by cooling makes it possible to reduce the temperature of drying air at the end of the second stage of drying in existing plants from 125-155 ° C to 60-70 ° C and to utilize the heat of the spent drying air of the first stage of drying when the final moisture content of the chips reaches 4%. Productivity increases by 14-25% with a decrease in specific heat consumption per 1 kg of evaporated moisture by 12-48%, despite the relatively small additional heat consumption for heating the cold, dried air before it is fed to the second stage of the drying apparatus.

2. Two-stage installation for drying liquid dairy products.

The first stage of drying is carried out in a spray dryer at an initial concentration of condensed milk of 48% and an initial temperature of drying air of 265-295 ° C, and the second stage of drying is carried out in a vibration dryer, where the powder enters at a humidity of 8% after the first stage of drying from a spray dryer. The final moisture content of the dispersed milk powder at the outlet of the apparatus of the second drying stage is 4.5%.

As in the first example, the results of calculation of indicators are compared for the same initial conditions used as a drying agent:

- atmospheric air taken from the external environment at a temperature of + 25 ° C (without drying by cooling);

- drying air previously drained by cooling to + 5 ° C and to minus 15 ° C.

When drying using air pre-dried by cooling, the temperature at the inlet to the apparatus of the second stage of drying decreases to 52-65 ° C, at the exit to 30-35 ° C, the productivity of the installation increases by 32-40%, the specific heat consumption decreases by 23 -35%.

In both the first and second examples, the probability of a fire is eliminated. This happens despite the high initial temperature of the drying air at the inlet to the apparatus of the first drying stage, because at the exit from it, the dispersed product has a high humidity. In this case, the air temperature at the outlet of the apparatus of the first drying stage and in the apparatus of the second drying stage as a whole remains significantly lower than the temperature of possible spontaneous combustion of the product.

Thus, the claimed installation has completed the technical task of the utility model:

increased productivity of the installation due to the more full use of the moisture capacity potential of drying air, low-temperature heat of exhausted drying air from the apparatuses of the first and second stages of drying was utilized directly in the technological process at the same installation, the heat consumption for heating the drying air of the second stage of drying was significantly reduced, and dry cooled to normal temperature the product without additional energy costs for its cooling, the negative impact of high t the temperature of the drying agent on the quality of the product and the fire hazard of the process at the installation.

Claims (15)

1. Installation for the implementation of two-stage drying of capillary-porous materials, which includes a device for intake from the environment and air supply for the first drying stage, a heater for heating it, an apparatus for the first drying stage, a device for supplying a drying gas to the first drying apparatus , apparatus for a second drying stage, a device for feeding wet material into a apparatus for a first stage, a heat exchanger for heating drying air of a second drying stage, a device for gas cleaning of exhaust dried gas of a first a drying stage with a fitting for the outlet of the purified spent drying air of the first drying stage, a gas duct for transferring the spent drying gas from the apparatus of the first drying stage to the gas cleaning system of the first drying stage, a device for unloading and supplying pre-dried material from the apparatus of the first drying stage to the receiving nozzle of the second apparatus drying stage, a device for unloading from the gas treatment system of the drying gas of the first drying stage of the captured dispersed material, the exhaust gas treatment system was dried of air of the second drying stage with fittings for entering and exiting exhaust drying air of the second drying stage, a device for collecting and supplying drying air of the second drying stage, characterized in that the apparatus includes a cooler for artificial cooling of the drying air of the second drying stage, a device for separating from the cooled drying air of the second stage of drying moisture in the form of condensate or ice, a gas duct connecting the outlet of the device for intake and supply of drying air for the second stage with ears with a fitting for entering drying air into a device for artificial cooling of drying air of a second drying stage, wherein a fitting for leaving cooled air from a device for artificial cooling of drying air of a second drying stage is connected via a duct to a fitting for supplying cooled drying air of a second drying stage to a device for moisture separation in the form of condensate or ice from the cooled drying air of the second stage of drying, and its fitting for the exit of the cooled dried air with Uniform through duct with a nozzle for the entrance of dry cooled air drying in the second stage heat exchanger for heating the drying air in the second drying step. 2. Installation according to claim 1, characterized in that the gas duct connecting the outlet fitting of the device for taking in the environment and supplying drying air for the second drying stage with a fitting for entering the drying air into the device for artificial cooling of the drying air of the second drying stage is connected by duct with a duct connecting the fitting for the exit of chilled air from the device for artificial cooling of the drying air of the second stage of drying with a fitting for supplying cooled air to the device for moisture in the form of condensate or ice from the cooled drying air of the second stage of drying, moreover, on the fittings for entering and exiting the cooled drying air of the second stage of drying, a device for artificially cooling the drying air of the second stage of drying and on the duct connecting the duct between the nozzle for the exit of drying air devices for intake and supply of drying air of the second stage of drying and a fitting for entering the drying air into the device for artificial cooling of drying air of the second stage of su ki duct between the connection for the entrance of the apparatus for separating the moisture from the cooled air of the second drying step of drying and outlet fitting for the cooled air from the air cooler of the second drying step are set locking and regulating devices. 3. The installation according to claim 1, characterized in that the installation includes a device for artificial cooling of air of the first drying stage, a device for separating moisture from condensed or ice from the first drying air of the first drying stage, a fitting for entering the cooled air into the cooler for artificial cooling of the air of the first drying stage is connected by means of a gas duct to a device for intake and supply of drying air of the first drying stage, and a fitting for leaving the cooled air by means of a gas duct is connected to a fitting for entering the cooled air of the first drying stage into a device for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, and its fitting for leaving the cooled dried air through a duct is connected to a fitting for entering the heated medium into the air heater for heating the air of the first drying stage . 4. The installation according to claim 1, characterized in that the installation includes a device for artificial cooling of the air of the first drying stage, a device for separating moisture from the cooled drying air of the first stage in the form of condensate or ice, a heat exchanger for preheating the drying air of the first stage drying from an additional source, the nozzle for entering the cooled air into the cooler for artificial cooling of the air of the first stage of drying is connected by means of a duct to the device for intake and supply drying air of the first drying stage, and the nozzle for leaving the cooled air through a gas duct is connected to the nozzle for entering the cooled air of the first drying stage into a device for separating moisture in the form of condensate or ice from the cooled air of the first drying stage, and its nozzle for leaving the cooled dried air by the gas duct is connected to the fitting for entering the heated medium into the heat exchanger for preheating the drying air of the first drying stage, and its fitting for connecting the heated medium with a fitting for entering the heated medium into the air heater for heating the air of the first drying stage. 5. Installation according to claim 1, characterized in that the installation includes a device for artificial cooling of air of the first drying stage, a device for separating moisture from condensed or ice from the first cooling air of the first drying stage, a heat exchanger for heating the drying air of the first drying stage from an additional source, and the fitting for entering the cooled air into the device for artificial cooling of air of the first stage of drying is connected by means of a gas duct to a device for collecting and supplying a dryer the air of the first drying stage, the nozzle for leaving the cooled gas of the cooler for artificial cooling of the air of the first drying stage by means of a duct is connected to the nozzle for entering the cooled air into the device for separating moisture from the cooled drying air of the first drying stage, and its nozzle for leaving the cooled dried air through the duct connected to the nozzle for entering the heated medium into the heat exchanger for preheating the drying gas, the nozzle of which is connected to the outlet of the heated medium with a fitting for entering the heated medium into the heater for heating the air of the first stage of drying, and on the nozzles for entering and exiting the cooled air of the device for artificial cooling of the drying air of the first stage of drying and on the gas duct connecting the supply nozzle of the device for intake and supply of drying air for the first stage drying with a duct connecting the fitting for the exit of the cooled air from the air cooler of the first stage of drying with the fitting for the entrance of the dried cooled air of the first stage of drying in the heat exchanger for heating the drying air of the first drying step, shut-mounted control devices. 6. Installation according to claim 1, characterized in that the installation includes a device for artificial cooling of air of the first drying stage, a device for separating moisture from condensed or ice from the first drying air of the first drying stage, a heat exchanger for heating the drying air of the first drying stage from an additional source, the gas duct connecting the outlet of the device for intake from the environment and supply of drying air for the second stage of drying with a fitting for the entrance of drying air into the device for the artificial cooling of the drying air of the second drying stage, is connected by means of a gas duct to the duct connecting the nozzle for the exit of the cooled air from the device for the artificial cooling of the drying air of the second drying stage with a fitting for supplying cooled air to the device for separating moisture in the form of condensate or ice from the cooled drying the air of the second stage of drying, on the fittings for the inlet and outlet of the device for artificial cooling of the drying air of the second stage and on the duct, connecting we take the duct between the nozzle for the drying air outlet of the device for intake and supply of drying air of the second stage of drying and the nozzle for the entrance of the drying air into the device for artificially cooling the drying air of the second stage of drying with the duct between the nozzle for entering the device for separating moisture from the cooled drying air of the second drying stage and fitting for the exit of chilled air from the device for cooling the drying air of the second drying stage, locking and control devices are installed, a cooling air inlet for a device for artificial cooling of air of a first drying stage is connected via a gas duct to a device for intake and supply of drying air of a first drying stage, a nozzle for leaving a cooled gas of a device for artificial cooling of drying air of a first drying stage is connected to a chilled inlet for cooling air into the device for separating moisture from the cooled drying air of the first drying stage, and its nozzle for the exit of the cooled dried the air through the gas duct is connected to the nozzle for entering the heated medium into the heat exchanger for preheating the drying air, the nozzle of which for exiting the heated medium is connected to the nozzle for entering the heated medium into the heater for heating the air of the first drying stage, and on the nozzles for entering and leaving the cooled air of the device for artificial cooling of the drying air of the first drying stage and on the gas duct connecting the supply nozzle of the device for intake and supply of drying air for the first drying stage With a duct connecting the outlet for cooled air from the device for artificial cooling of the drying air of the first drying stage with a fitting for entering the dried cooled air of the first drying stage in the heat exchanger for heating the drying air of the first drying stage, shut-off and control devices are installed. 7. Installation according to claims 4-6, characterized in that the nozzle for the outlet of the cleaned exhaust drying air from the gas purification system of the second drying stage is connected via a gas duct to the nozzle for entering the coolant into the heat exchanger for preheating the cooled drying air of the first drying stage. 8. Installation according to claims 4-6, characterized in that the fitting for the outlet of the purified spent drying air from the gas cleaning system of the second drying stage is connected to the fitting for entering the heat carrier into the heat exchanger for preheating the cooled drying air of the first drying stage by means of a duct that has a fitting for supplying coolant to it from an additional heat source. 9. Installation according to claims 4-6, characterized in that the outlet nozzle of the system for gas purification of the spent drying gas of the first drying stage is connected via a gas duct to the nozzle for entering the heat carrier into the heat exchanger for preheating the cooled drying air of the first drying stage. 10. Installation according to claims 4-6, characterized in that the outlet nozzle of the system for gas purification of the spent drying gas of the first drying stage is connected to a fitting for entering the coolant into the heat exchanger for preheating the cooled drying air of the first drying stage by means of a duct that has a nozzle for supplying heat carrier from an additional heat source into it. 11. Installation according to claims 4-6, characterized in that the nozzle for exiting the cleaned exhaust drying air from the gas treatment system of the second drying stage is connected via a gas duct to the nozzle for entering the coolant into the heat exchanger for preheating the cooled drying air of the first drying stage, the nozzle for the outlet of the purified drying air from the system for gas purification of the exhaust drying gas of the first drying stage is connected by means of a gas duct to a fitting for entering the heat carrier into the heat exchanger for pre aritelnogo heating the cooled first air drying the drying step. 12. Installation according to claims 4-6, characterized in that the nozzle for the outlet of the purified spent drying air from the gas treatment system of the second drying stage is connected via a gas duct to the nozzle for entering the heat carrier into the heat exchanger for preheating the cooled drying air of the first drying stage, and the outlet nozzle systems for gas treatment of spent drying gas of the first drying stage is connected to a fitting for entering the coolant into the heat exchanger for preheating the cooled drying air of the first drying stages by means of a flue, wherein the nozzle for entering the heat carrier into the heat exchanger for preheating the cooled drying air of the first drying stage is connected to the nozzle for supplying the heat carrier to the heat carrier from an additional source. 13. Installation according to claims 4-6, characterized in that the fitting for the outlet of the cleaned exhaust drying air from the gas treatment system of the second drying stage is connected via a gas duct to the fitting for entering the heat carrier into the heat exchanger for preheating the cooled drying air of the first drying stage, and the fitting for the outlet of the purified drying air from the system for gas purification of the spent drying gas of the first drying stage is connected to the fitting for the coolant to enter the heat exchanger for pre-heating dried drying air of the first drying stage by means of a duct that has a nozzle for supplying heat from an additional source, the nozzle of the gas cleaning system for exhausting the exhaust drying gas of the first drying stage is connected to a nozzle for entering the heat carrier into the heat exchanger for heating the cooled drying air of the second drying stage by means of a duct, which has a fitting for supplying heat to it from an additional source. 14. Installation according to claims 1 to 6, characterized in that the nozzle for the outlet of the purified spent drying gas of the gas cleaning system of the first drying stage is connected via a gas duct to the nozzle for entering the heat carrier into the heat exchanger for heating the cooled drying air of the second drying stage. 15. Installation according to claims 1 to 6, characterized in that the fitting for the outlet of the purified spent drying gas from the gas cleaning system of the first drying stage is connected via a gas duct to the fitting for entering the heat carrier into the heat exchanger for heating the cooled drying air of the second drying stage, the heat exchanger having a fitting for supplying a heat carrier with an additional heat source.

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