Environment-friendly municipal sludge drying system

Abstract

The utility model discloses an environment-friendly municipal sludge drying system, belongs to the field of sludge treatment processes, and is suitable for drying treatment of municipal sludge. The drying system comprises a hot blast stove, a heat exchanger, a condenser, a collector, a dryer and a waste gas treatment device, and can further comprise a high-temperature mixing chamber; the dryer adopts a gas drying mode, a material inlet of the dryer is connected with treated moisture-containing sludge, a gas source inlet is connected with high-temperature drying air, and the moisture-containing sludge is dried by the high-temperature drying air; a material inlet of the collector is connected with a dried material outlet of the dryer, a dried finished product is collected, and low-temperature moisture-containing air is discharged; the condenser condenses the low-temperature moisture-containing air to obtain condensed water and low-temperature dry air; the heat exchanger receives high-temperature hot air and low-temperature dry air to exchange heat in the heat exchanger to obtain waste gas and high-temperature dry air; and the hot blast stove supplies high-temperature hot air to the heat exchanger by introducing cold air and heating. The sludge drying system has the remarkable advantages of high drying efficiency, stable and safe operation, energy conservation, environmental protection, cost saving and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste treatment, and particularly relates to an environment-friendly municipal sludge drying system. Background Art

[0002] In the disposal of municipal sludge, reducing the moisture content of sludge is the core task, because too high moisture content of sludge will cause a large amount of toxic and harmful substances to be released. Generally, the moisture content of sludge needs to be reduced to less than 50% to meet the requirements of landfill. The existing technologies basically adhere to the principles of reduction, stabilization, harmlessness and resource utilization for the disposal of municipal sludge. The sludge disposal is a process with high energy consumption and high investment, resulting in high treatment costs, which restricts the development of sludge treatment. Therefore, how to further optimize the sludge drying technology, reduce the process cost and improve the comprehensive utilization level of the products is still a problem to be solved. Summary of the Invention

[0003] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an environment-friendly municipal sludge drying system in order to reduce the energy consumption of sludge drying and improve the drying efficiency.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions.

[0005] An environment-friendly municipal sludge drying system includes:

[0006] A dryer, which adopts a gas drying method. Its material inlet receives the wet sludge to be treated, and its gas source inlet receives high-temperature drying air. The high-temperature drying air is used to dry the wet sludge.

[0007] A collector, whose material inlet is connected to the dried material outlet of the dryer, collects the dried finished products and discharges the low-temperature wet air.

[0008] A condenser, which condenses the low-temperature wet air to obtain condensed water and low-temperature drying air.

[0009] A heat exchanger, which is connected to the high-temperature hot air and the low-temperature drying air to exchange heat between them, obtaining waste gas and the high-temperature drying air.

[0010] A hot blast stove, which introduces cold air and heats it to provide the high-temperature hot air for the heat exchanger.

[0011] In one embodiment, the drying system of the present invention further includes: a high-temperature mixing chamber; the high-temperature mixing chamber is arranged behind the hot blast stove, and fully mixes the system leakage air and the hot air of the hot blast stove to obtain mixed hot air, and the mixed hot air provides the high-temperature hot air for the heat exchanger; the system leakage air is the shunt air of the low-temperature drying air, and a part of the low-temperature drying air enters the heat exchanger, and the other part enters the high-temperature mixing chamber as the shunt air.

[0012] In one embodiment, a circulation system is formed among the high-temperature mixing chamber, the heat exchanger, the dryer, the collector, and the condenser through multiple sections of connecting pipelines, and air enters each device in sequence to form a circulating air flow.

[0013] In one embodiment, the hot air outlet of the high-temperature mixing chamber is communicated with the hot air inlet of the heat exchanger through an air duct, the high-temperature drying air outlet of the heat exchanger is communicated with the hot air inlet of the dryer through an air duct, the system air leakage outlet of the condenser is communicated with the system air leakage inlet of the high-temperature mixing chamber through an air duct, and make-up air is introduced at the hot blast stove.

[0014] In one embodiment, the waste gas treatment device is communicated with the waste gas outlet of the heat exchanger through a connecting pipeline, and the waste gas treatment device purifies the waste gas containing pollutants discharged from the waste gas outlet of the heat exchanger.

[0015] In one embodiment, the heat exchanger includes a high-temperature hot air inlet, a low-temperature drying air inlet, a high-temperature drying air outlet, and a waste gas outlet. The high-temperature hot air heats the low-temperature drying air to obtain high-temperature drying air, and the high-temperature hot air and the low-temperature drying air do not directly contact, and only heat energy is transferred.

[0016] In one embodiment, the collector is a cyclone separator, which realizes the separation of the dried product and the low-temperature moist air by using the rotational movement of the air flow and the difference in the sedimentation velocity of different material particle sizes.

[0017] The present invention also provides an environment-friendly municipal sludge drying method, which is realized based on the environment-friendly municipal sludge drying system, and the process is as follows:

[0018] Send the moist sludge to be treated into the dryer and perform drying treatment with high-temperature drying air. During the drying process of the sludge, the moisture absorbs heat and undergoes a phase change to enter the drying air as vapor, and the hot air is cooled by heat absorption to form low-temperature moist air.

[0019] Send the dried product and the low-temperature moist air into the collector, the dried product is collected, and the low-temperature moist air is discharged.

[0020] Send the low-temperature moist air into the condenser for dehumidification to obtain low-temperature drying air.

[0021] Use the hot blast stove to heat the cold air to obtain high-temperature hot air.

[0022] Exchange heat between the low-temperature drying air and the high-temperature hot air through the heat exchanger to obtain high-temperature drying air and send it back to the dryer.

[0023] In one embodiment, the low-temperature drying air is divided into two parts. One part enters the heat exchanger, and the other part, as the shunt air, i.e., the system leakage air, enters the high-temperature mixing chamber, mixes with the high-temperature hot air to obtain the final high-temperature hot air, and the final high-temperature hot air replaces the high-temperature hot air of the hot blast stove and enters the heat exchanger.

[0024] In the present invention, the moisture content of the wet sludge is 70% - 80%, the moisture content of the dried product is reduced to 8% - 12%, the temperature range of the high-temperature drying air is 200°C - 850°C, the temperature of the low-temperature wet air is 70°C - 80°C, the moisture content is 30% - 40%, the temperature range of the low-temperature drying air is 50°C - 70°C, and the temperature range of the high-temperature hot air is 350°C - 850°C.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1) The circulating air system adopted by the system is efficient and low-energy-consuming, enabling the circulating air to be reused repeatedly, avoiding waste of heat energy, and following the principle of energy conservation and environmental protection.

[0027] 2) The leakage air can be collected and reused through the high-temperature mixing chamber, realizing the recycling of energy.

[0028] 3) The equipment of the system forms a closed loop, with a simple and compact structure. The high-temperature hot air supplied by the hot blast stove converges through two-stage equipment and then is input into the dryer, making full use of the hot air, improving the drying efficiency and drying effect, and enabling the system to operate stably and continuously.

[0029] In summary, the present invention has many advantages and application values. It has great improvements in both structure and function, significant progress in technology, and good practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic structural diagram of Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The embodiments of the present invention will be described in detail below with reference to the drawings and examples.

[0032] To improve the drying efficiency of wet sludge, the present invention adopts a circulating air system configuration and proposes a new drying system that saves energy and has a relatively high drying efficiency.

[0033] Refer to Figure 1 As shown, in the embodiment of the present invention, the environmental protection municipal sludge drying system mainly includes a dryer, a collector, a condenser, a heat exchanger, and a hot blast stove.

[0034] Among them, the dryer adopts a gas drying method and is used to dry the wet sludge. It has a material inlet, a gas source inlet, and a dried material outlet. The material inlet receives the wet sludge to be processed, and the gas source inlet receives high-temperature drying air. The high-temperature drying air is used to dry the wet sludge. For example, the temperature range of the high-temperature drying air output by the heat exchanger is generally about 200°C to 850°C, the temperature range of the waste gas output by the heat exchanger is generally 110°C to 120°C, and the moisture content of the wet sludge is generally 70% to 80%.

[0035] The collector is used to collect the dried material obtained by the dryer and has a material inlet, a material outlet, and an air outlet. Its material inlet is connected to the dried material outlet of the dryer. After the material is dried by the dryer, it enters the collector together with the air and is separated. The solid is the dried finished product, which can be collected and discharged from its material outlet. The gas is low-temperature wet air and is discharged from the air outlet. For example, the moisture content of the dried finished product is generally about 10%, the temperature range of the low-temperature wet air is generally about 70°C to 80°C, and the moisture content is generally 30% to 40%.

[0036] The condenser is used to condense the low-temperature wet air to obtain condensed water and low-temperature drying air, and has a refrigerant medium, an air inlet, an air outlet, and a water outlet. Its air inlet is connected to the air outlet of the collector. The low-temperature wet air is condensed by the refrigerant medium, the condensed water is discharged from the water outlet, and the low-temperature drying air is discharged from the air outlet.

[0037] For example, the temperature range of the low-temperature drying air is generally about 60°C and generally contains no water.

[0038] The heat exchanger is used to heat the low-temperature drying air to obtain high-temperature drying air and has a high-temperature hot air inlet, a low-temperature drying air inlet, a high-temperature drying air outlet, and an exhaust gas outlet. Its high-temperature hot air inlet is connected to the high-temperature hot air, the low-temperature drying air inlet is connected to the air outlet of the condenser, the high-temperature drying air outlet is connected to the gas source inlet of the dryer, and the exhaust gas outlet discharges the exhaust gas. In the heat exchanger, the low-temperature drying air and the high-temperature hot air exchange heat. The heat of the high-temperature hot air is used to heat the low-temperature drying air to obtain high-temperature drying air, and the high-temperature hot air after heating is transformed into exhaust gas. During the process, the high-temperature hot air and the low-temperature drying air do not directly contact, only heat energy is transferred. The low-temperature drying air containing harmful pollutants can be recycled in the system, and the pollutants will not accumulate, reducing the generation of new harmful pollutants. For example, the temperature range of the high-temperature hot air is generally 350°C to 850°C and generally contains no water.

[0039] The hot blast stove is used to provide the high-temperature hot air for the heat exchanger and has a cold air inlet and a high-temperature hot air outlet. It has an internal heat source and heats the incoming cold air to obtain high-temperature hot air. The hot blast stove heats the air (i.e., cold air) in the heating gas channel, so that the air absorbs heat and increases in temperature.

[0040] According to the drying system of the present invention, the heat exchanger outputs high-temperature drying air as circulating hot air and returns it to the dryer again, providing supplementary heat source for drying. It can make full use of the waste heat in the drying process and reuse it in the drying system, forming a closed circulating air path, and the whole system forms a self-circulation. Thus, it can continuously and stably treat municipal sludge. During operation, it can efficiently utilize the hot air to form a circulating air path, greatly reducing energy consumption, being more environmentally friendly, and having remarkable advantages such as high drying efficiency, stable and safe operation, energy conservation, environmental protection and cost savings.

[0041] In a further embodiment of the present invention, the sludge drying system further includes a high-temperature mixing chamber. The high-temperature mixing chamber is arranged behind the hot blast stove and has a hot air inlet or a supplementary air inlet, a system air leakage inlet and a hot air outlet. Its main function is to fully mix the system air leakage and the hot air from the hot blast stove to obtain mixed hot air, and use the mixed hot air as the high-temperature hot air provided to the heat exchanger, thereby replacing the scheme of directly using the hot air from the hot blast stove. In the present invention, the system air leakage is a part of the shunt air of the low-temperature drying air. A part of the low-temperature drying air directly enters the heat exchanger, and the other part is used as shunt air. Shunting can make the system air pressure stable, reduce the loss of air supply, and prevent the polluted air that has circulated in the system from flowing into the non-polluted area. And sending the shunt air into the high-temperature mixing chamber can be recycled, reducing the generation of new pollutants.

[0042] In this embodiment, the high-temperature mixing chamber can make the mixed air uniform, and the temperature of the mixed hot air is stable with a small change range, so as to ensure stable heat supply for the whole system. The high-temperature hot air output by the hot blast stove is mixed evenly with the system air leakage and then used as the high-temperature hot air supplied to the heat exchanger.

[0043] In a further embodiment of the present invention, a closed circulation system is formed among the high-temperature mixing chamber, the heat exchanger, the dryer, the collector and the condenser through multiple connecting pipes, and air enters each device in turn to form a circulating air path. Among them, the circulating air can be reused repeatedly, thus saving energy. At the same time, the circulating air will not be discharged, reducing environmental pollution and avoiding waste of heat energy. The power for the system air circulation can be provided by the drive of the hot blast stove.

[0044] In a further embodiment of the present invention, the hot air outlet of the high-temperature mixing chamber is communicated with the hot air inlet of the heat exchanger through a duct, the high-temperature drying air outlet of the heat exchanger is communicated with the hot air inlet of the dryer through a duct, and the system air leakage outlet of the condenser is communicated with the system air leakage inlet of the high-temperature mixing chamber through a duct. To maintain the hot air circulation in the system, supplementary air is introduced at the hot blast stove. To treat the discharged waste gas, the waste gas outlet of the heat exchanger is communicated with the waste gas treatment device through a connecting pipe, and the polluted waste gas discharged from the heat exchanger is purified before being discharged to avoid polluting the environment.

[0045] In a further embodiment of the present invention, the exhaust gas treatment device may also be arranged between the hot air outlet of the high-temperature mixing chamber and the hot air inlet of the heat exchanger to preliminarily treat the high-temperature hot gas.

[0046] In a further embodiment of the present invention, the collector is specifically selected as a cyclone separator, which can utilize the rotational movement of the airflow and the difference in the sedimentation velocities of different material particle sizes to separate the dried product and the low-temperature moist air.

[0047] In a further embodiment of the present invention, the heat exchanger is a finned-tube heat exchanger or a plate heat exchanger.

[0048] According to the above system, the drying process of the present invention is as follows:

[0049] The moist municipal sludge to be treated enters the dryer from the material inlet for drying treatment. During the drying process, the moisture in the sludge absorbs heat and undergoes a phase change to enter the drying air as vapor. The hot air is cooled by absorbing heat to form low-temperature moist air. The mixed dried product and low-temperature moist air enter the collector together, and the dried product and low-temperature moist air are collected separately. The dried product is discharged from the material outlet of the collector, and the low-temperature moist air enters the condenser for dehumidification to be transformed into low-temperature dry air. A part of the low-temperature dry air enters the heat exchanger, and a small part, as the shunt air, that is, the system leakage air, enters the high-temperature mixing chamber to be reused. The hot blast stove heats the high-temperature mixing chamber, and the obtained hot air heats the low-temperature dry air in the heat exchanger to obtain high-temperature dry air. The high-temperature dry air is used as the circulating hot air and enters the dryer to be utilized, and then enters the system for circulation again. The exhaust gas treatment device is arranged behind the heat exchanger, and the generated exhaust gas is treated to meet the standards before being discharged to avoid environmental pollution.

[0050] The above are only the preferred examples of the present invention and do not impose any formal restrictions on the present invention. Although the present invention has been disclosed above with preferred examples, it is not intended to limit the present invention. Any person skilled in the art of the present invention can make any minor changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes. However, as long as the content does not depart from the technical solution of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly municipal sludge drying system, characterized in that: include: The dryer adopts a gas drying method, wherein the material inlet receives the wet sludge to be treated, and the air source inlet receives high-temperature drying air, and the high-temperature drying air is used to dry the wet sludge; A collector, whose material inlet is connected to the dry material outlet of the dryer, collects the dried product and discharges low-temperature humid air; A condenser, condensing the low-temperature humid air to obtain condensed water and low-temperature dry air; A heat exchanger, receiving the high-temperature hot air and the low-temperature dry air so that the two exchange heat therein to obtain exhaust gas and the high-temperature dry air; The hot air furnace is fed with cold air and heated to provide the high-temperature hot air for the heat exchanger.

2. The environmentally friendly municipal sludge drying system according to claim 1 is characterized in that: Also includes: High temperature mixing chamber; the high temperature mixing chamber is arranged after the hot air stove, and the system leakage air and the hot air of the hot air stove are fully mixed to obtain mixed hot air, and the mixed hot air provides high temperature hot air for the heat exchanger; the system leakage air is the diversion air of the low temperature dry air, part of the low temperature dry air enters the heat exchanger, and the other part enters the high temperature mixing chamber as the diversion air.

3. The environmentally friendly municipal sludge drying system according to claim 2 is characterized in that: The high-temperature mixing chamber, heat exchanger, dryer, collector, and condenser form a circulation system through multiple sections of connecting pipes, and air enters each device in turn to form circulating wind.

4. The environmentally friendly municipal sludge drying system according to claim 2 is characterized in that: The hot air outlet of the high-temperature mixing chamber is connected to the hot air inlet of the heat exchanger through an air duct, the high-temperature drying air outlet of the heat exchanger is connected to the hot air inlet of the dryer through an air duct, the system leakage air outlet of the condenser is connected to the system leakage air inlet of the high-temperature mixing chamber through an air duct, supplementary air is introduced into the hot air furnace, and the exhaust gas outlet of the heat exchanger is connected to the exhaust gas treatment device through a connecting pipe, and the polluted exhaust gas discharged from the heat exchanger is purified and discharged.

5. The environmentally friendly municipal sludge drying system according to claim 4 is characterized in that: The exhaust gas treatment device is connected to the exhaust gas outlet of the heat exchanger through a connecting pipe, and the exhaust gas treatment device purifies the polluted exhaust gas discharged from the exhaust gas outlet of the heat exchanger.

6. The environmentally friendly municipal sludge drying system according to claim 1 is characterized in that: The heat exchanger includes a high-temperature hot air inlet, a low-temperature dry air inlet, a high-temperature dry air outlet and an exhaust gas outlet. The high-temperature hot air heats the low-temperature dry air to obtain high-temperature dry air, and the high-temperature hot air and the low-temperature dry air are not in direct contact, and only heat energy is transferred.

7. The environmentally friendly municipal sludge drying system according to claim 1 is characterized in that: The collector is a cyclone separator, which utilizes the rotational motion of the airflow and the difference in sedimentation speed of different material particle sizes to separate the dried product and the low-temperature humid air.

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