阅读说明：本技术 一种烘干机尾气余热回收装置及烘干机和余热回收方法 (Dryer tail gas waste heat recovery device, dryer and waste heat recovery method ) 是由 张绪坤 黄家振 傅伟良 张城镇 邢普 李康康 范发林 周文华 于 2021-09-13 设计创作，主要内容包括：本发明公开一种烘干机尾气余热回收装置及烘干机和余热回收方法,包括沿尾气流出方向顺次布置且对尾气余热进行连续换热的板式换热器和二次换热器,板式换热器分别与烘干机的尾气管路和进气管路相连通,进气管路的进气温度低于尾气管路的尾气温度,二次换热器包括通过换热工质循环管路相连通的蒸发器和冷凝器,且蒸发器和冷凝器分别与尾气管路和进气管路相连通,一方面,利用板式换热器和二次换热器依次对尾气中的余热进行回收利用,形成对尾气余热的多级处理,保证了对尾气余热的充分利用；另一方面,进气依次经过蒸发器和板式换热器的逐级加热,使得进气逐渐升温,进而在烘干机的加热腔中无需消耗过多的能量,充分降低了烘干机的能耗。(The invention discloses a dryer tail gas waste heat recovery device, a dryer and a waste heat recovery method, and the device comprises a plate heat exchanger and a secondary heat exchanger which are sequentially arranged along the tail gas outflow direction and continuously exchange heat for tail gas waste heat, wherein the plate heat exchanger is respectively communicated with a tail gas pipeline and an air inlet pipeline of the dryer, the air inlet temperature of the air inlet pipeline is lower than the tail gas temperature of the tail gas pipeline, the secondary heat exchanger comprises an evaporator and a condenser which are communicated through a heat exchange working medium circulation pipeline, and the evaporator and the condenser are respectively communicated with the tail gas pipeline and the air inlet pipeline; on the other hand, the air inlet is sequentially heated step by step through the evaporator and the plate heat exchanger, so that the temperature of the air inlet is gradually increased, excessive energy does not need to be consumed in the heating cavity of the dryer, and the energy consumption of the dryer is fully reduced.)

1. The utility model provides a drying-machine tail gas waste heat recovery device, its characterized in that includes and arranges in order and carry out the plate heat exchanger and the secondary heat exchanger of continuous heat transfer to the tail gas waste heat along tail gas outflow direction, plate heat exchanger is linked together with the tail gas pipeline and the air inlet pipeline of drying-machine respectively, the inlet air temperature of air inlet pipeline is less than the tail gas temperature of tail gas pipeline, secondary heat exchanger includes evaporimeter and the condenser that are linked together through heat transfer working medium circulation pipeline, just evaporimeter and condenser respectively with the tail gas pipeline with the air inlet pipeline is linked together.

2. The tail gas waste heat recovery device of the dryer according to claim 1, wherein the evaporator and the condenser are respectively provided with an evaporation cavity and a condensation cavity for the circulation of tail gas and inlet air, and the heat exchange working medium circulation pipeline is arranged in the evaporation cavity and the condensation cavity in a penetrating manner.

3. The waste heat recovery device of the dryer tail gas as claimed in claim 1 or 2, wherein the secondary heat exchanger further comprises a compressor for compressing a heat exchange working medium and an expansion valve for decompressing the heat exchange working medium, and the evaporator, the compressor, the condenser and the expansion valve are sequentially communicated along the flow direction of the heat exchange working medium.

4. A dryer using the dryer exhaust gas waste heat recovery device of any one of claims 1 to 3, comprising a dryer body, the exhaust gas pipeline, the air inlet pipeline and the dryer waste heat recovery device, wherein the dryer body comprises a heating cavity for heating inlet air and drying materials, and the exhaust gas pipeline and the air inlet pipeline are both communicated with the heating cavity.

5. The dryer of claim 4, wherein a humidity sensor is disposed at the air outlet of the heating chamber, the humidity sensor is electrically connected to an air outlet fan for opening air extraction to the heating chamber according to a detection value of the humidity sensor, and the air outlet fan is disposed on the exhaust gas pipeline.

6. The dryer of claim 5, wherein the air inlet duct is provided with an air inlet fan for introducing air into the heating chamber, and the air inlet fan and the air outlet fan are synchronously linked.

7. The dryer according to any one of claims 4 to 6, wherein a cyclone separator for filtering dust particles in the exhaust gas is arranged on the exhaust gas pipeline, and the cyclone separator is positioned between the heating cavity and the plate heat exchanger.

8. The dryer of claim 7, wherein a filter for filtering fine dust in the exhaust gas is disposed between the cyclone separator and the plate heat exchanger.

9. The dryer according to claim 8, wherein said exhaust duct is connected to a plurality of groups of filtering ducts provided with said filter, and each of said filtering ducts is provided with a stop valve at a position on both sides of said filter.

10. A waste heat recovery method of a dryer is characterized by comprising the following processes:

introducing air into the heating cavity: according to the fact that the humidity at the outlet of the heating cavity detected by the humidity sensor reaches an index value, an air inlet fan and an air outlet fan are started, air is introduced into the heating cavity through an air inlet pipeline, and tail gas is led out of the heating cavity through a tail gas pipeline;

heat exchange of the plate heat exchanger: introducing tail gas and air into the plate heat exchanger, and preheating the air before entering the heating cavity by using the waste heat of the tail gas;

heat exchange of a secondary heat exchanger: the tail gas flowing out of the tail gas heat exchange cavity is introduced into an evaporation cavity of the evaporator, the tail gas in the evaporation cavity exchanges heat with a heat exchange working medium in a heat exchange working medium circulation pipeline, the heat exchange working medium is heated to form low-pressure high-temperature steam, the low-pressure high-temperature steam flows into the compressor through the heat exchange working medium circulation pipeline, the low-pressure high-temperature steam is pressurized and heated through the compressor to form high-temperature high-pressure steam, the high-temperature high-pressure steam is introduced into the condenser and exchanges heat with air in the condensation cavity, the air after heat exchange flows into the plate type heat exchanger, the high-temperature high-pressure steam is condensed into high-pressure low-temperature liquid after heat exchange, and the high-pressure low-temperature liquid becomes low-temperature low-pressure liquid through an expansion valve and then flows back to the evaporator for cyclic utilization.

Technical Field

The invention relates to the technical field of waste heat recovery, in particular to a dryer tail gas waste heat recovery device, a dryer and a waste heat recovery method.

Background

In the prior art, tempering and drying are two important processes in feed production. The conditioning is a process of introducing saturated steam into the powder under high temperature and high pressure to cure the powder, and the conditioning can improve the forming capacity of the feed, improve the quality of granules, improve the water resistance of the granulated feed, improve the nutrient digestibility of the feed, reduce the forming energy consumption, kill harmful bacteria and facilitate the addition of liquid; and the drying is mainly used for removing the redundant moisture in the feed, facilitating the subsequent storage and preventing the mildew. At present, high-temperature and high-humidity waste gas (the temperature is between 80 and 100 ℃) generated after a dryer is used by a plurality of processing enterprises for drying feed is directly discharged without utilization, and the annual temperature of air sucked in an air inlet of the dryer is only about 20 ℃. If the energy consumption required by heating the air at the temperature of 20 ℃ to 100 ℃ required by drying the feed is extremely high, if the waste heat recovery is carried out on the high-temperature and high-humidity tail gas discharged from the exhaust port and the air inlet temperature of the air inlet is increased, the energy consumption of the dryer can be greatly reduced, and the effects of energy conservation and emission reduction are realized.

In the industrial field of China, waste heat resources are ubiquitous, and a large amount of waste heat resources exist in the production process of industries such as building materials, metallurgy, feed, tea making and the like. Wherein, the waste heat resource in the tea drying process accounts for 35 to 50 percent of the total drying energy consumption. (Wuzeqiu et al, experimental research on recycling waste heat of a tea dryer [ J ]. agricultural machinery research, 2013, 35 (12): 141-: 144.) this is basically the same as the heat taken away by waste gas, which is experimentally measured by researchers such as germanium cast steel and the like when drying paddy, of about 32.8% and as high as 1/3 (research on energy-saving technology of various cast steel and cylindrical dryers [ J ]. grain and oil storage science and technology communication, 1987 (04): 24-27.), and it can be presumed that the heat taken away by waste gas in dried feed is also quite large. In the experiment of Wuzeque et al for drying tea, experimenters adopt a shell-and-tube heat exchanger to carry out heat exchange on high-temperature waste gas of a dryer and cold air at an air inlet of the dryer, the cold air at the air inlet is increased to 42-47 ℃ from 20 ℃, so that the initial temperature of air entering a fan is increased by about 20-25 ℃, and the heat exchange effect is obvious. According to literature data (Wu Yougei et al. simulation analysis of absorption type wet and hot air waste heat recovery system [ J ]. Heat energy Power engineering, 2014, 29 (05): 498 +593.) it is known that simple heat exchange is directly adopted, on one hand, due to the existence of heat transfer temperature difference, preheated air is inevitably lower than exhaust temperature, on the other hand, about 70% of energy in exhaust gas is contained in water vapor, and the dew point temperature is only about 61 ℃, so that a relatively ideal energy recovery rate can be obtained through heat exchange only below 60 ℃.

Chinese patent (publication No. CN205641936U) discloses a waste heat recycling system for a fodder dryer, which can absorb and utilize the waste heat of the dryer to a certain extent, but mainly absorbs the heat inside the dryer, while the heat in the exhaust gas cannot be effectively utilized.

Chinese patent (publication number: CN 210135801U) discloses a waste heat recycling device of an expanded feed dryer, which recycles waste heat of tail gas of the dryer to a certain extent, but adopts a simple heat exchanger to recycle the waste heat of the tail gas at the first stage, and finally recycles liquid with higher temperature, so that the waste heat of the dryer is not fully recycled, and the tail gas is not treated.

Disclosure of Invention

The invention aims to provide a dryer tail gas waste heat recovery device, a dryer and a waste heat recovery method, which are used for solving the problems in the prior art.

In order to achieve the purpose, the invention provides the following scheme: the invention provides a dryer tail gas waste heat recovery device which comprises a plate heat exchanger and a secondary heat exchanger, wherein the plate heat exchanger and the secondary heat exchanger are sequentially arranged along the tail gas outflow direction and continuously exchange heat for tail gas waste heat, the plate heat exchanger is respectively communicated with a tail gas pipeline and an air inlet pipeline of a dryer, the air inlet temperature of the air inlet pipeline is lower than the tail gas temperature of the tail gas pipeline, the secondary heat exchanger comprises an evaporator and a condenser which are communicated through a heat exchange working medium circulation pipeline, and the evaporator and the condenser are respectively communicated with the tail gas pipeline and the air inlet pipeline.

Preferably, the evaporator and the condenser are respectively provided with an evaporation cavity and a condensation cavity for tail gas and inlet gas to flow through, and the heat exchange working medium circulation pipeline is arranged in the evaporation cavity and the condensation cavity in a penetrating manner.

Preferably, the secondary heat exchanger further comprises a compressor for compressing a heat exchange working medium and an expansion valve for decompressing the heat exchange working medium, and the evaporator, the compressor, the condenser and the expansion valve are sequentially communicated along the flow direction of the heat exchange working medium.

Still provide a drying-machine, including the drying-machine body the tail gas pipeline the air inlet pipeline with the double recovery unit of drying-machine waste heat, the drying-machine body is including the heating chamber that is used for heating admit air and dry material, the tail gas pipeline with the air inlet pipeline all with the heating chamber is linked together.

Preferably, the air outlet of the heating chamber is provided with a humidity sensor, the humidity sensor is electrically connected with an air outlet fan which is started to exhaust air from the heating chamber according to a detection value of the humidity sensor, and the air outlet fan is arranged on the tail gas pipeline.

Preferably, the air inlet pipeline is provided with an air inlet fan for introducing air into the heating cavity, and the air inlet fan and the air outlet air are synchronously linked.

Preferably, a cyclone separator for filtering dust particles in the tail gas is arranged on the tail gas pipeline, and the cyclone separator is located between the heating cavity and the plate heat exchanger.

Preferably, a filter for filtering fine dust in the tail gas is arranged between the cyclone separator and the plate heat exchanger.

Preferably, the tail gas pipeline is communicated with a plurality of groups of filtering pipelines provided with the filters, and stop valves are arranged at the positions of the filtering pipelines, which are positioned at the two sides of the filters.

Also provides a waste heat recovery method of the dryer, which comprises the following processes:

introducing air into the heating cavity: according to the fact that the humidity at the outlet of the heating cavity detected by the humidity sensor reaches an index value, an air inlet fan and an air outlet fan are started, air is introduced into the heating cavity through an air inlet pipeline, and tail gas is led out of the heating cavity through a tail gas pipeline;

heat exchange of the plate heat exchanger: introducing tail gas and air into the plate heat exchanger, and preheating the air before entering the heating cavity by using the waste heat of the tail gas;

heat exchange of a secondary heat exchanger: the tail gas flowing out of the tail gas heat exchange cavity is introduced into an evaporation cavity of the evaporator, the tail gas in the evaporation cavity exchanges heat with a heat exchange working medium in a heat exchange working medium circulation pipeline, the heat exchange working medium is heated to form low-pressure high-temperature steam, the low-pressure high-temperature steam flows into the compressor through the heat exchange working medium circulation pipeline, the low-pressure high-temperature steam is pressurized and heated through the compressor to form high-temperature high-pressure steam, the high-temperature high-pressure steam is introduced into the condenser and exchanges heat with air in the condensation cavity, the air after heat exchange flows into the plate type heat exchanger, the high-temperature high-pressure steam is condensed into high-pressure low-temperature liquid after heat exchange, and the high-pressure low-temperature liquid becomes low-temperature low-pressure liquid through an expansion valve and then flows back to the evaporator for cyclic utilization.

Compared with the prior art, the invention has the following technical effects:

firstly, a plate heat exchanger and a secondary heat exchanger are sequentially arranged along the tail gas outflow direction and sequentially carry out continuous heat exchange on the waste heat of the tail gas, the plate heat exchanger is respectively communicated with a tail gas pipeline and an air inlet pipeline of a dryer, the air inlet temperature of the air inlet pipeline is lower than the tail gas temperature of the tail gas pipeline, the secondary heat exchanger comprises an evaporator and a condenser which are communicated with each other through a heat exchange working medium circulation pipeline, the evaporator and the condenser are respectively communicated with the tail gas pipeline and the air inlet pipeline, in terms of the tail gas flow direction, on one hand, the plate heat exchanger and the secondary heat exchanger are utilized to sequentially recycle the waste heat in the tail gas to form multi-stage treatment on the waste heat of the tail gas, on the other hand, the secondary heat exchanger adopts a mode of combining the evaporator and the condenser with the heat exchange working medium circulation pipeline, namely, the waste heat in the tail gas passing through the plate heat exchanger is recycled by utilizing the heat exchange working medium, because the waste heat in the tail gas passing through the plate heat exchanger is fully weakened, the waste heat can be fully collected even if the content of the waste heat in the tail gas is reduced by utilizing the characteristic of easy volatilization of the heat exchange working medium after being heated, and the heat of the tail gas can be released by utilizing the evaporator after the heat exchange working medium is treated, so that the full utilization of the waste heat of the tail gas is ensured; from the direction of air inflow, the air inflow is sequentially heated step by step through the evaporator and the plate heat exchanger, so that the temperature of the air inflow is gradually increased, excessive energy does not need to be consumed in a heating cavity of the dryer, the air inflow can be heated to the required drying temperature, and the energy consumption of the dryer is fully reduced.

Secondly, evaporimeter and condenser are equipped with the evaporation chamber and the condensation chamber that supply tail gas and inlet air circulation respectively, heat transfer working medium circulation pipeline runs through the setting in evaporation chamber and condensation chamber, the heat transfer working medium passes through heat transfer working medium circulation pipeline and flows in evaporation chamber and condensation chamber, not only can guarantee to evaporate chamber and condensation intracavity gas and carry out the heat transfer through heat transfer working medium circulation pipeline, and can guarantee that the heat transfer working medium seals to flow in heat transfer working medium circulation pipeline, avoid it to change the leakage that the flow pipeline caused the heat transfer working medium easily.

Thirdly, the secondary heat exchanger also comprises a compressor for compressing the heat exchange working medium and an expansion valve for decompressing the heat exchange working medium, the evaporator, the compressor, the condenser and the expansion valve are sequentially communicated along the flow direction of the heat exchange working medium, the heat exchange working medium exchanges heat with the tail gas in the evaporator to form low-pressure high-temperature steam, the heat exchange working medium is compressed by the compressor to form high-temperature high-pressure steam, the temperature of the heat exchange working medium is further increased, the heating effect of the inlet air in the condenser is ensured, the high-temperature high-pressure steam after condensation forms low-temperature high-pressure liquid, the low-temperature high-pressure liquid forms low-temperature low-pressure liquid by the expansion valve, the flow speed of the low-temperature high-pressure liquid in the evaporator is ensured to be reduced, and the heat exchange working medium is fully utilized to exchange heat with the tail gas.

Fourth, the gas outlet department in heating chamber is equipped with humidity transducer, humidity transducer electricity is connected with opens the fan of giving vent to anger of bleeding in the heating chamber according to its detected value, the fan setting of giving vent to anger is on the tail gas pipeline, just can open the fan of giving vent to anger when temperature transducer detects the humidity of giving vent to anger in the heating chamber and reaches the predetermined value, avoid the fan of giving vent to anger to reach and still open when the predetermined value at humidity, still open the fan of giving vent to anger when need not to let in the air, lead to the energy consumption to increase.

Fifthly, the last intercommunication of tail gas pipeline has the filter tube that a plurality of groups were equipped with the filter, the position department that each filter tube is located the filter both sides all is equipped with the stop valve, carry out abundant filtration to tail gas through the filter, pollute external gas when avoiding tail gas discharge, and when needs clear up the filter, can close the pipeline of the filter of treating the clearance through the stop valve, only utilize all the other filter tubes to carry out tail gas filtration, guarantee the continuous recovery of tail gas waste heat, avoid leading to tail gas recovery work to stop because of clearing up the filter, cause drying efficiency to hang down.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic view of the overall structure of the present invention;

the dryer comprises a dryer body 1, a gas outlet fan 2, a cyclone separator 3, a filtering pipeline 4, a stop valve 5, a filter 6, a plate heat exchanger 7, an evaporator 8, a tail gas pipeline 9, a gas inlet pipeline 10, a gas inlet fan 11, a compressor 12, a condenser 13 and an expansion valve 14.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a dryer tail gas waste heat recovery device, a dryer and a waste heat recovery method, which are used for solving the problems in the prior art.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Referring to fig. 1, the present invention provides a dryer tail gas waste heat recovery device, including a plate heat exchanger 7 and a secondary heat exchanger, which are sequentially arranged along a tail gas outflow direction and continuously exchange heat for tail gas waste heat, wherein the plate heat exchanger 7 is respectively communicated with a tail gas pipeline 9 and an air intake pipeline 10 of a dryer, the plate heat exchanger 7 includes a tail gas heat exchange cavity for tail gas circulation, an air intake heat exchange pipe for dryer air intake is arranged in the tail gas heat exchange cavity, the tail gas heat exchange cavity is communicated with the tail gas pipeline 9, the air intake heat exchanger is communicated with the air intake pipeline 10, preferably, the air intake heat exchange pipe can be arranged in the tail gas heat exchange cavity in a serpentine structure, and a heat exchange fin can also be arranged, and an intake temperature of the air intake pipeline 10 is lower than a tail gas temperature of the tail gas pipeline 9; the secondary heat exchanger comprises an evaporator 8 and a condenser 13 which are communicated through a heat exchange working medium circulation pipeline, and the evaporator 8 and the condenser 13 are respectively communicated with a tail gas pipeline 9 and an air inlet pipeline 10; in the flow direction of the tail gas, on one hand, the plate heat exchanger 7 and the secondary heat exchanger are utilized to sequentially recycle the waste heat in the tail gas to form multi-stage treatment of the waste heat of the tail gas, on the other hand, the secondary heat exchanger adopts a mode that the evaporator 8 and the condenser 13 are combined with a heat exchange working medium circulation pipeline, namely, the heat exchange working medium is utilized to recycle the waste heat in the tail gas passing through the plate heat exchanger 7, and the waste heat in the tail gas passing through the plate heat exchanger 7 is fully weakened, so that the heat-volatile characteristic of the heat exchange working medium is utilized, the waste heat can be fully collected even if the content of the waste heat in the tail gas is reduced, the evaporator 8 is utilized to release the heat after the heat exchange working medium is treated, and the full utilization of the waste heat of the tail gas is ensured; from the air inflow direction, the air inflow is sequentially heated step by step through the evaporator 8 and the plate heat exchanger 7, so that the air inflow is gradually heated, excessive energy does not need to be consumed in the heating cavity of the dryer, the air inflow can be heated to the required drying temperature, the energy consumption of the dryer is fully reduced, specifically, the drying medium of the dryer is air, and the energy consumption for directly heating the air which is not preheated is larger than that for heating the air which is preheated. For example, compared with the case of heating the air at the normal temperature of 20 ℃ to 90 ℃ and the case of heating the air at the temperature of 50 ℃ to 90 ℃ after preheating, the energy consumption of the latter is reduced.

Further, evaporimeter 8 and condenser 13 are equipped with the evaporation chamber and the condensation chamber that supply tail gas and inlet air circulation respectively, heat transfer working medium circulation pipeline runs through the setting in evaporation chamber and condensation chamber, the heat transfer working medium flows in evaporation chamber and condensation chamber through heat transfer working medium circulation pipeline, not only can guarantee to evaporate chamber and condensation intracavity gas and carry out the heat transfer through heat transfer working medium circulation pipeline, and can guarantee that the heat transfer working medium seals to flow in heat transfer working medium circulation pipeline, avoid it to change the leakage that the flow pipeline caused the heat transfer working medium easily, it can be equipped with heat transfer fin etc. on the heat transfer working medium circulation pipeline outer wall that is located evaporation chamber and condensation intracavity preferentially, and heat exchange efficiency is improved.

The secondary heat exchanger further comprises a compressor 12 for compressing a heat exchange working medium and an expansion valve 14 for decompressing the heat exchange working medium, the evaporator 8, the compressor 12, the condenser 13 and the expansion valve 14 are sequentially communicated along the flow direction of the heat exchange working medium, the heat exchange working medium exchanges heat with tail gas in the evaporator 8 to form low-pressure high-temperature steam, the low-pressure high-temperature steam is compressed by the compressor 12 to form high-temperature high-pressure steam, so that the temperature of the heat exchange working medium is further increased, the temperature rise effect of inlet air in the condenser 13 is ensured, the high-temperature high-pressure steam after condensation forms low-temperature high-pressure liquid, the low-temperature high-pressure liquid forms low-temperature low-pressure liquid by the expansion valve 14, the flow speed of the low-temperature high-pressure liquid in the evaporator 8 is ensured to be reduced, and the heat exchange working medium is fully utilized to exchange heat with the tail gas.

Further, still provide a drying-machine, especially carry out the drying-machine of drying to popped fodder, including drying-machine body 1, tail gas pipeline 9, the double recovery unit of air inlet pipeline 10 and drying-machine waste heat, drying-machine body 1 is including the heating chamber that is used for heating admit air and dry the material, tail gas pipeline 9 and air inlet pipeline 10 all are linked together with the heating chamber, wherein, drying-machine has air inlet and gas outlet, air inlet and gas outlet link to each other with air inlet pipeline 10 and tail gas pipeline 9 respectively, preferred tail gas pipeline 9, air inlet pipeline 10, the heat transfer working medium circulation pipeline that is located the evaporimeter 8 and condenser 13 outside has the cladding of steam generator all to have the heat preservation, with the loss of each gas in the heat energy of pipeline flow. As a preferred embodiment of the invention, the air inlet is located at the bottom of the heating cavity, the air outlet is located at the top of the heating cavity, so that air can gradually diffuse into the whole heating cavity, and an air charging effect in the heating cavity is ensured, an evenly distributed exhaust passage is preferably arranged between the air inlet and the heating cavity, so that the air is further uniformly dried for materials in the whole heating cavity, and the preferred exhaust gas pipeline 9 at the air outlet forms a bending section, so that condensed water formed by heating moisture in the exhaust gas pipeline 9 is gathered in the bending section, and the condensed water is prevented from flowing back to the heating cavity.

As a preferred embodiment of the present invention, a humidity sensor is disposed at an air outlet of the heating chamber, the humidity sensor is electrically connected to an air outlet fan 2 that starts to exhaust air from the heating chamber according to a detection value of the humidity sensor, so as to form feedback regulation, the air outlet fan 2 is disposed on the tail gas pipeline 9, high-temperature and high-humidity gas is extracted through an air outlet of the heating chamber, the air outlet fan 2 is started only when the temperature sensor detects that the humidity of the air outlet in the heating chamber reaches a predetermined value, and therefore, the situation that the air outlet fan 2 is still started when the humidity does not reach the predetermined value, and the air outlet fan 2 is still started when air does not need to be introduced, which leads to an increase in energy consumption is avoided.

Preferably, the air inlet pipeline is provided with an air inlet fan 11 used for introducing air into the heating cavity, and the air inlet fan 11 and the air outlet air are synchronously linked to ensure the air inflow of the heating cavity in the dryer.

As a preferred embodiment of the invention, the tail gas pipeline 9 is provided with a cyclone separator 3 for filtering dust particles in the tail gas, the air outlet of the heating cavity is connected with the cyclone separator 3 through a part of the tail gas pipeline 9, the cyclone separator 3 is positioned between the heating cavity and the plate heat exchanger 7, and after cyclone dust removal, particulate matters with the diameter larger than 5 μm in the tail gas are basically and completely removed.

Furthermore, a filter 6 for filtering micro-dust in the tail gas is arranged between the cyclone separator 3 and the plate type heat exchanger 7, the filter 6 is a high-temperature-resistant and high-efficiency filter 6, the filter element is made of high-temperature-resistant glass fiber, the filtering efficiency of the filter element on 0.3 mu m fine dust particles reaches 99.99%, and the filter element can continuously operate in a high-temperature 280 ℃ working environment. The tail gas is fully filtered by the filter 6, so that the tail gas is prevented from polluting the external gas when being discharged, dust particles, namely larger particles (the diameter is more than 5 mu m), are removed by the cyclone dust collector, and the dust removal effect of 90 percent can be achieved. Then the filter 6 is used for filtering the tiny dust, namely fine dust particles (the diameter is about 0.3 mu m), so as to avoid the influence of the dust entering the heat exchanger on the heat exchange process. Furthermore, the dryer tail gas after cyclone dust removal and filtration by the filter 6 and double heat exchange condensation basically does not contain micro particle impurities and moisture, and pollution-free emission after waste heat recovery is realized.

Further, the last intercommunication of tail gas pipeline 9 has the filter tube 4 that a plurality of groups were equipped with filter 6, each group of filter tube 4 communicates in cyclone 3's exit jointly, for being the inlet port department that is connected to plate heat exchanger 7 all the way behind filter 6, each filter tube 4 all is equipped with stop valve 5 in the position department that is located filter 6 both sides, it is concrete, use a filter 6, can influence entire system's normal operating when taking place to block up, because when specifically clearing up, need dismantle filter 6, take outdoor use hair-dryer to clear up adnexed dust on the filter screen. When needing to clear up filter 6, can close the pipeline of the filter 6 that will treat the clearance through stop valve 5, only utilize all the other filter tube ways to carry out tail gas filtration, form alternate use promptly, guarantee the continuous recovery of tail gas waste heat, avoid stopping because of clearance filter 6 leads to tail gas recovery work, cause drying efficiency to hang down. Specifically, the amount of fine particles attached to the exhaust gas of the dryer is large, and the filter 6 is easily clogged. When the filter 6 is excessively adhered with dust, the filter element can be cleaned by water, the cleaning temperature is 30-60 ℃, and the soaking and cleaning time is 30-60 minutes.

Also provides a waste heat recovery method of the dryer, which comprises the following processes:

introducing air into the heating cavity: according to the fact that the humidity at the outlet of the heating cavity detected by the humidity sensor reaches an index value, the air inlet fan 11 and the air outlet fan 2 are started, air is introduced into the heating cavity through the air inlet pipeline, and tail gas is led out of the heating cavity through the tail gas pipeline 9;

and 7, heat exchange of the plate heat exchanger: introducing tail gas and air into the plate heat exchanger 7, and preheating the air before entering the heating cavity by using the waste heat of the tail gas;

heat exchange of a secondary heat exchanger: the tail gas flowing out of the tail gas heat exchange cavity is introduced into an evaporation cavity of the evaporator 8, the tail gas in the evaporation cavity exchanges heat with a heat exchange working medium in a heat exchange working medium circulation pipeline, the heat exchange working medium is heated to form low-pressure high-temperature steam, the low-pressure high-temperature steam flows into the compressor 12 through the heat exchange working medium circulation pipeline, the low-pressure high-temperature steam is pressurized and heated through the compressor 12 to form high-temperature high-pressure steam, the high-temperature high-pressure steam is introduced into the condenser 13 and exchanges heat with air in a condensation cavity, the air after heat exchange flows into the plate heat exchanger 7, the high-temperature high-pressure steam is condensed into high-pressure low-temperature liquid after heat exchange, and the high-pressure low-temperature liquid becomes low-temperature low-pressure liquid through the expansion valve 14 and then flows back to the evaporator 8 to be recycled.

The adaptation according to the actual needs is within the scope of the invention.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.