CN100559103C - Solar energy and high-temperature double-heat-source heat pump sludge drying system - Google Patents

Abstract

The invention relates to a drying device for wet materials. The drying machine is internally provided with a multi-layer belt type conveying device, an air channel and an air inlet and outlet channel connected with the heat pump, a wet material feeding device is arranged on a feed inlet of the drying machine, a discharge port outputs dry materials, the drying machine is provided with a solar air heat collector, and an auxiliary air inlet is arranged on the heat pump; the solar air heat collector is provided with a fan, an air outlet of the fan is respectively connected with an auxiliary air inlet of the heat pump and an air inlet channel between the dryer and the heat pump through a pipeline provided with a valve, and an air inlet of the fan is respectively connected with an air outlet channel between the dryer and the heat pump and the outside through a pipeline provided with a valve. The invention greatly saves energy consumption, and the dried sludge realizes stabilization, reduction, harmlessness and recycling.

Description

Solar energy, high temperature dual heat source heat pump sludge drying system

technical field

The invention relates to a drying device for wet materials, in particular to a processing equipment capable of drying wet sludge in large quantities.

Background technique

At present, sludge drying has become an important means of sludge treatment, and has attracted the attention of environmental engineering circles including developing countries. The existing sludge drying methods mainly adopt mechanical drying, mainly including flash evaporation, thin film, spray, multi-effect evaporation and other types. Its technical principles are heat conduction, heat convection and heat radiation. However, using these technologies to dry sludge consumes a lot of energy. In order to ensure the safety performance of the drying system and avoid secondary pollution, it is necessary to have a complete set of equipment as a reliable guarantee, which greatly increases the cost of sludge treatment. Due to the one-time investment and high operating costs of sludge drying, many urban sewage treatment plants are "daunted", which seriously hinders the process of sludge treatment in small and medium-sized urban sewage treatment plants. At present, many small and medium-sized urban sewage treatment plants are "overcrowded with mud", which has caused secondary pollution to the environment.

Contents of the invention

The invention provides a solar energy, high temperature dual heat source heat pump sludge drying system which uses solar energy as an auxiliary heat source and is combined with large flow processing equipment.

The technical solution of the present invention is: it includes a dryer and a heat pump, the dryer is provided with a multi-layer belt conveying device, an air duct and an air inlet and outlet duct connected to the heat pump, and a wet material feeding device is provided on the feed port of the dryer , the discharge port outputs dry materials, the drying system is also provided with a solar air collector, and an auxiliary air inlet is provided on the heat pump; a fan is provided on the solar air collector, and the air outlet of the solar air collector The auxiliary air inlet of the heat pump and the air inlet between the dryer and the heat pump are respectively connected through a pipeline with a valve, and the air inlet of the fan is respectively connected with the outlet between the dryer and the heat pump through a pipeline with a valve. The air duct is connected to the outside world.

It also has a controller, each pipeline is equipped with temperature and air volume sensors, the valves on each pipeline are electromagnetic valves, and each temperature sensor, air volume sensor, and electromagnetic valve are respectively connected to the controller.

The wet material feeding device at the feed port of the dryer includes a material conveyor belt, a mixing and conveying integrated machine, and a granulator connected in sequence.

The granulator is a secondary granulator.

The invention changes the mode of using a single heat source to dry wet materials in the prior art, and adds a solar air heat collector to the system as an auxiliary heat source of the heat pump, which greatly saves energy consumption. The mature drying technology "sludge mixing granulation drying system" ensures the processing capacity of the system and makes the treated sludge have secondary use value. The dried sludge has achieved stabilization, reduction, harmlessness and resource utilization. The controllers, sensors and solenoid valves installed in the system can enable the system to realize automatic operation according to the environmental conditions, and can adjust whether to start the heat pump according to the ambient temperature, because the temperature of solar energy in summer in the south can already meet the processing needs. The invention has high degree of automation, less energy consumption and good treatment effect.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of the present invention

In the figure, 1 is a discharge port, 2 is a dryer, 3 is a secondary granulator, 4 is a mixing and conveying machine, 5 is a heat pump, 6 is a solar collector, and 7 is a fan.

Fig. 2 is a working principle diagram of the present invention

Detailed ways

As shown in Fig. 1, the present invention comprises a drier 2 and heat pump 5, is provided with multi-layer belt conveyer, air duct and the inlet and outlet air duct that connects heat pump 5 in the drier 2, is provided with wet material on the feed port of drier 2 Feeding device, discharge port 1 outputs dry materials, it is provided with solar air heat collector 6, and auxiliary air inlet is provided on heat pump 5; fan 7 is provided on solar air heat collector 6, and its air outlet passes through respectively The pipe provided with the valve is connected with the auxiliary air inlet of the heat pump 5 and the air inlet between the dryer 2 and the heat pump 5, and the air inlet passes through the pipe provided with the valve and the outlet between the dryer 2 and the heat pump 5 respectively. The air duct is connected to the outside world.

The present invention is also provided with a controller, each pipeline is provided with temperature and air volume sensors, the valves on each pipeline are electromagnetic valves, and each temperature, air volume sensor, and electromagnetic valve are respectively connected to the controller.

The wet material feeding device at the feed port of the dryer 2 includes a material conveyor belt, a secondary granulator 3 and a mixing and conveying integrated machine 4 connected in sequence.

As shown in Figure 2, the working principle of the present invention is:

① The sludge is mechanically dehydrated in the dewatering machine. After dehydration, the moisture content of the sludge is about 80%, and it is sent to the quantitative feeder by the shaftless screw conveyor for quantitative feeding.

②Through two sets of quantitative feeders, the sludge with a moisture content of 80% and a moisture content of 10% is sent to the mixing and conveying integrated machine 4 by the belt conveyors I and II respectively to mix the dry and wet sludge evenly. (The purpose of this is to avoid the sticky properties of the sludge during the drying process, so that it will not cause adhesion and hardening during drying, and the phenomenon of impermeable drying, and also expand the allowable fluctuation of the moisture content of the wet sludge scope.)

③ Mix 50% (moisture content 80%) wet sludge and 50% (moisture content 10%) dry sludge evenly in the integrated sludge mixing and conveying machine 4, and the moisture content of the mixed sludge is ≤ 50% .

④ The mixed sludge flows to the vertical secondary granulator 3 for granulation. The granulator is a Class II granulator with a particle diameter of 3 mm. The particles are uniform and solid, and the yield is >98%.

⑤The continuous multi-group stainless steel mesh belt dryer 2 is a closed rectangular body, length × width × height = 5.3m × 1.5m × 3m. There are three sets of stainless steel perforated belt conveyors, distributed up and down in the height direction, connected end to end, with an effective drying area of 15.6m ² . The granular sludge is evenly distributed on the stainless steel mesh belt through the rotary feeding valve and the distributor, and the conveyor belt speed and mud thickness can be automatically adjusted (when the temperature of the hot air inside the machine changes, the running speed of the mesh belt will be automatically adjusted to ensure that the granular sludge mud final moisture content). The conveyor transports the granular sludge back and forth according to the set speed, and turns over to evaporate the moisture of the sludge particles. The amount of sludge treated by the dryer 2 is 250kg/h, and the residence time of the material in the dryer 2 is 1h. The drying strength of the dryer 2 (2.5kg H ₂ O/h·m bandwidth. The temperature of the hot air in the dryer 2 is 80°C, and a good hot air circulation system is installed in the dryer 2. The hot air is circulated to the conveyor belt through the fan to dry the granular sludge. Finally, the granular sludge with a moisture content of ≤10% is sent out of the dryer 2 through the rotary valve. The hot and humid gas absorbing the moisture in the granular sludge is discharged by the induced draft fan and sent to the dust removal device for dust removal, and then sent to the heat pump 5 for dehumidification.

⑥The heat pump 5 is composed of a compressor, a condenser, a throttling device and an evaporator. Among them, the flowing working medium absorbs the heat in the hot and humid gas discharged from the dryer 2 in the evaporator, evaporates from the low-pressure liquid working medium into low-pressure steam, and is pressurized by the compressor to become high-temperature and high-pressure steam; in the condenser, the high-temperature The high-pressure working medium releases heat to heat the dry gas after dehumidification, while the working medium itself condenses from gas to high-pressure liquid, and the throttling device has a blocking effect on the high-pressure liquid working medium, reducing the pressure. Repeatedly, a heat pump system is formed. Heat and dehumidification cycle.

The gas discharged from the dryer 2 is hot and humid gas with a high moisture content, and its relative humidity is about 75-80%. The surface condenses the water and exits the system as liquid water. The relative temperature of the warm gas is reduced, and after becoming a dry gas, it enters the heat pump 5 to increase heat to provide heat for sludge drying. The gas is an isenthalpy temperature increase and decrease process in the dryer 2, and a dehumidification and temperature increase process in the heat pump 5. The heat pump 5 Exhaust hot air temperature ≥ 90 ℃. The system adopts high-temperature homogeneous and high-efficiency energy-saving dehumidification and heating units with good performance, and the heating coefficient COP of the heat pump 5 is >4. In addition to self-circulating dehumidification and heating, the heat pump 5 can also take heat from different heat sources. When the temperature of the hot air from the solar collector 6 meets the temperature inside the dryer 2, the hot air from the solar collector 6 will supply heat. 2 temperature, the solar heat collector 6 hot air is used as the low-level energy of the heat pump 5, and in cold seasons, electricity or other waste heat heating air can also be used as the low-level energy of the heat pump 5, and the energy conversion of the heat pump 5 is all completed automatically.

⑦ Flat-plate solar collector 6

The heat source for sludge drying consists of a heat pump 5 and a solar collector 6 to form a heat supply system, and the heat pump 5 is a key device in the heat supply system. The solar thermal collector 6 is an auxiliary device in the heating system. When the temperature of the vapor compression heat pump 5 is very low in winter, the efficiency of the heat pump 5 system is low, while the solar thermal collector 6 has a high heat collection efficiency at low temperatures. The heat pump system and The combination of solar heat collection system effectively solves this problem. The use of solar energy improves the energy-saving benefit of drying and reduces the cost of drying. The solar heat collector 6 is a flat-plate, assembled air heat collector, with a total lighting area of 130m ² ; the solar air heat collector 6 can effectively collect solar radiation energy and convert it into solar energy, heat the air to a certain temperature, and send it through pipelines. To dryer 2 or heat pump 5. The solar heating system is composed of solar collectors 6, fans 7, air inlet and exhaust valves and pipes. The collectors are arranged in an array, and the collectors and heat-absorbing panels are mesh panels. The design of the air flow channel is reasonable, and the insulation effect of the insulation layer is good, which ensures that the sun's radiation energy is converted into the latent heat energy of the air to the greatest extent. The heat collection efficiency of the solar panel collector reaches 60%.

In summary, the energy consumption cost of the present invention is low, the heat pump 5 can recover sensible heat and latent heat in the warm air, and the energy has been fully and reasonably utilized, and is a recognized high-efficiency energy-saving device. The joint work of solar energy and heat pump further improves Reduced energy consumption. Does not pollute the environment, solar energy is green energy, the whole process of drying sludge by solar heat pump is a closed system, does not need to discharge moisture, and will not discharge harmful odor at the same time, sludge with a moisture content of 10% after drying has become Odorless particles (can be directly sold or used as commodities), will not pollute the environment. The quality of sludge drying is good. The solar heat pump drying system dries sludge in a closed space and is not affected by external climate conditions. It runs smoothly under the same conditions throughout the year, so the drying quality is stable. Sludge is a colloidal solid micromass squeezed out by flocculant precipitation. It has complex composition structure and strong water absorption. The drying temperature of the dryer can be adjusted, and the speed of the conveyor belt can be controlled, which meets the ideal sludge drying. Conditions, the moisture content of the dried product is uniform, and the organic components in the granular sludge can be maintained (such as heavy metals that do not exceed the standard can be used as fertilizers), which is conducive to the utilization of sludge resources. The safety is good. Due to the multi-belt dryer used in the drying of sludge particles, the running speed is low and the operation is stable. The sludge particles will not rub against each other to generate dust, and the reasonable hot air configuration will not raise dust. The temperature in the drying room is less than 80°C, which is low-temperature drying. The sludge particles will not spontaneously ignite due to overheating during the drying process, avoiding the unsafe hidden dangers caused by dust accumulation and sludge spontaneous combustion in conventional sludge drying. Compact structure, small footprint, high degree of automation, the entire drying process can be fully automatic, semi-automatic or manual configuration to meet the needs of different users. The utility model has a wide range of uses, and the present invention can also be used in the drying of agricultural products and industrial raw materials in addition to being used for sludge drying.

Claims (4)

1. Solar energy, high temperature dual heat source heat pump sludge drying system, which includes a dryer and a heat pump. The dryer is equipped with multi-layer belt conveyors, air ducts and inlet and outlet air ducts connected to the heat pump. The feed port of the dryer is equipped with There is a wet material feeding device, and the output port outputs dry materials. It is characterized in that the drying system is also equipped with a solar air collector, and an auxiliary air inlet is provided on the heat pump; a fan is provided on the solar air collector. The air outlet of the solar air heat collector is respectively connected to the auxiliary air inlet of the heat pump and the air inlet between the dryer and the heat pump through a pipeline provided with a valve; The pipeline is connected with the air outlet between the dryer and the heat pump, and the outside world. 2. The solar energy, high temperature dual heat source heat pump sludge drying system according to claim 1, characterized in that it is also equipped with a controller, each pipeline is equipped with temperature and air volume sensors, and the valves on each pipeline are It is a solenoid valve, and each temperature sensor, air volume sensor, and solenoid valve are respectively connected to the controller. 3. The solar energy, high temperature dual heat source heat pump sludge drying system according to claim 1, characterized in that the wet material feeding device at the feed port of the dryer includes a material conveyor belt connected in sequence, a mixing and conveying integrated machine, a manufacturing Granulator. 4. The solar energy, high temperature dual heat source heat pump drying system according to claim 3, characterized in that the granulator is a secondary granulator.

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