CN105859097A - Method and device for drying sludge by utilizing thermal power plant waste heat - Google Patents

Abstract

The invention discloses a method and device for drying sludge by utilizing thermal power plant waste heat. The device comprises a furnace, wherein a plate type feed conveying belt and a plate type discharge conveying belt are arranged in a hearth. Multiple layers of middle-layer plate type conveying belts are distributed between the plate type feed conveying belt and the plate type discharge conveying belt from top to bottom. The middle-layer plate type conveying belts divides an internal airflow channel of the hearth into S-shaped airflow channels. Drying air detours and flows in the hearth under the flow distributing effects of the airflow channels along an S-shaped flow track. Sludge falls to the first-layer middle-layer plate type conveying belt from the tail end of the plate type feed conveying belt, then sequentially falls to the plate type discharge conveying belt from the tail end of the first-layer middle-layer plate type conveying belt so that the sludge can move in the hearth along the S-shaped track from top to bottom, and finally the sludge is discharged out through the plate type discharge conveying belt. The device can save considerable high-grade electric energy, achieves drying by using lower-grade flue gas waste heat and has the advantages of being efficient, capable of saving energy, environmentally friendly, high in space utilization rate and facilitating large-scale drying.

Description

A method and device for drying sludge combined with thermal power plant waste heat utilization

technical field

The invention relates to a sludge drying process, in particular to a sludge drying method combined with thermal power plant waste heat utilization and a device thereof.

Background technique

With the development of cities, the number and scale of urban sewage treatment plants have grown rapidly, and these sewage treatment plants have produced a large amount of sludge. How to properly dispose of sludge and realize sludge recycling has become a key area of scientific research.

Even after conventional mechanical dehydration, the water content of municipal sludge is still above 80%, which is extremely unfavorable for sludge transportation, storage and further treatment. At present, the most common sludge drying method is blast drying by electric heating. However, this drying method consumes a large amount of high-grade electric energy, resulting in energy waste.

Contents of the invention

The object of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art, and provide a simple in structure, efficient and environment-friendly sludge drying method combined with thermal power plant waste heat utilization and its device.

The present invention realizes through following technical scheme:

A sludge drying device combined with thermal power plant waste heat utilization, comprising a furnace 4, a plate-type feeding conveyor belt 2-1 arranged on the inner upper part of the furnace 4, and a plate-type discharge conveying belt 2-2 arranged on the inner lower part of the furnace 4;

Between the plate feed conveyer belt 2-1 and the plate discharge conveyer belt 2-2, there are multi-layer middle plate conveyer belts 2-3 staggeredly distributed from top to bottom; The internal airflow channels are spaced into S-shaped airflow channels;

The lower side wall of the furnace 4 is provided with a drying air supply device; the drying air passes through the plate type discharge conveyor belt 2-2, the middle layer plate type conveyor belt 2-3 and the plate type feed conveyor belt 2-1 sequentially from bottom to top, drying Under the action of their diversion, the wind circulates in the furnace 4 in an S-shaped flow trajectory from bottom to top, and finally is discharged from the exhaust port on the top of the furnace 4;

When the sludge is transported into the furnace 4 through the plate feed conveyor belt 2-1, the sludge rolls down from the end of the plate feed conveyor belt 2-1 to the plate middle layer conveyor belt of the first layer, and then is transported by the first layer The end of the plate-type middle layer conveyor belt rolls down to the plate-type discharge conveyor belt 2-2 in turn, so that the sludge moves in the furnace 4 in an S-shaped track from top to bottom, and finally is sent out by the plate-type discharge conveyor belt 2-2.

The movement direction of the sludge in the furnace 4 is opposite to the flow direction of the drying wind in the furnace 4 .

The number of layers of the middle layer conveyor belt 2-3 is two or more layers, and the ends of the middle layer conveyor belts 2-3 of each layer are interlaced.

Between the plate feed conveyer belt 2-1, the middle plate conveyer belt 2-3 and the plate discharge conveyer belt 2-2, a deflector baffle 3 is added; on the wall.

The dry air supply device includes an absorption dehumidifier and a waste heat heater; air enters the waste heat heater from the absorption dehumidifier, and then is sent into the furnace 4 by the waste heat heater.

The exhaust port on the top of the furnace 4 is provided with a tail gas treatment device 1 , and the bottom of the furnace 4 is provided with a movable slag discharge plate 5 .

The tail gas treatment device 1 is a catalyst filter layer for filtering out harmful substances in the exhaust gas.

A wet sludge drying method combined with waste heat utilization of thermal power plants is as follows:

Step 1: Start the drying air supply device, and the drying air enters the furnace 4 from the bottom side of the furnace 4;

The drying air passes through the plate discharge conveyor belt 2-2, the middle layer plate conveyor belt 2-3 and the plate feed conveyor belt 2-1 sequentially from bottom to top, and the drying wind forms an S shape from bottom to top under their diversion The flow trajectory is circuitous in the furnace 4, and finally discharged to the atmosphere through the exhaust port on the top of the furnace 4;

Step 2: Start the plate feed conveyer belt 2-1, the plate discharge conveyer belt 2-2 and the middle plate conveyer belt 2-3 to make them run;

The sludge is placed on the plate feed conveyor belt 2-1, and is transported to the inner top of the furnace 4 by the plate feed conveyor belt 2-1, and the sludge is transported by the end of the plate feed conveyor belt 2-1 under the action of gravity Roll down to the first layer of the plate-type middle conveyor belt, and then continue to roll down from the end of the first layer of the plate-type middle layer conveyor belt to the next layer of the plate-type middle layer conveyor belt, so that the cycle is repeated; make the sludge from top to bottom The bottom moves in an S-shaped trajectory in the furnace 4, and gradually dries; this process prolongs the contact time and contact area between the sludge and the drying wind in the furnace 4, so that the sludge is fully dried;

The dried sludge is finally sent out through the plate type discharge conveyor belt 2-2.

The supply process of the drying wind supply device described in the above step one is as follows:

The outside air is first cooled and dehumidified by the evaporator, and then the temperature is raised by the condenser to reduce the relative humidity, and then reheated by the waste heat heater using the waste heat of the flue gas of the thermal power plant to further reduce the relative humidity, and then it is passed into the furnace 4 .

The temperature of the drying air in the above step 1 is 100°C to 150°C.

Compared with the prior art, the present invention has the following advantages and effects:

The lower side wall of the furnace 4 of the present invention is provided with a dry air supply device; the dry air passes through the plate type discharge conveyor belt 2-2, the middle layer plate type conveyor belt 2-3 and the plate type feed conveyor belt 2-1 from bottom to top. , the drying wind, under the effect of their diversion, flows from bottom to top in an S-shaped flow path in the hearth 4, and finally is discharged from the exhaust port on the top of the hearth 4; when the sludge is transported to the When inside the furnace 4, the sludge rolls down from the end of the plate feeding conveyor belt 2-1 to the plate type middle layer conveyor belt of the first layer, and then rolls down from the end of the plate type middle layer conveyor belt of the first layer to the plate type discharge conveyor The belt 2-2 makes the sludge move in the furnace 4 from top to bottom in an S-shaped trajectory, and finally is sent out by the plate type discharge conveyor belt 2-2. The structure of the present invention not only increases the contact time and contact area between the sludge and the drying wind in the furnace 4 during the drying process, so that the sludge can be dried more fully; it also makes full use of the space and reduces the equipment footprint .

In order to better make the time of the drying air stay in the furnace 4 and the contact time with the sludge, between the plate feed conveyor belt 2-1, the middle layer plate conveyor belt 2-3 and the plate discharge conveyor belt 2-2, The deflection baffle 3 is also added, which further improves the deflection effect on the drying wind, and fully prolongs the stroke of the drying wind in the furnace 4; further increases the residence time, so that the sludge can fully contact with the drying wind (hot air) , drying more completely.

The movement direction of the sludge in the furnace 4 of the present invention is opposite to the flow direction of the drying wind in the furnace 4, that is, the movement between them is reverse operation, and in a limited space, the drying speed and speed of the sludge are further strengthened. drying effect.

The speed of the slat conveyor belt of the present invention (that is, the slat feed conveyor belt 2-1, the middle layer slat conveyor belt 2-3 and the slab discharge conveyor belt 2-2) can be adjusted according to the working conditions, and the speed regulating device can be added. ;Considering that sludge drying will produce polluting waste gas, a tail gas purification device is installed on the top of the drying furnace to reduce the negative impact of sludge drying on the environment.

Compared with conventional drying methods, the technical means of the present invention are simple and easy to implement. It can save a large amount of high-grade electric energy, and achieve drying with lower-grade flue gas waste heat. It has the advantages of high efficiency, energy saving, environmental protection, high space utilization rate, and easy large-scale scale. It can be widely used in large-scale wet sludge processing. Drying treatment.

Description of drawings

Fig. 1 is a schematic structural diagram of a sludge drying device combined with thermal power plant waste heat utilization according to the present invention.

Fig. 2 is a schematic diagram of the structure of the drying air supply device.

detailed description

The present invention will be described in further detail below in conjunction with specific embodiments.

Example

As shown in Figures 1 and 2. The invention discloses a sludge drying device combined with waste heat utilization of a thermal power plant, comprising a furnace 4, a plate-type feeding conveyor belt 2-1 arranged on the inner upper part of the furnace 4, and a plate-type discharge conveying belt 2-2 arranged on the inner lower part of the furnace 4 ;

Between the plate feed conveyer belt 2-1 and the plate discharge conveyer belt 2-2, there are multi-layer middle plate conveyer belts 2-3 staggeredly distributed from top to bottom; The internal airflow channels are spaced into S-shaped airflow channels;

The lower side wall of the furnace 4 is provided with a drying air supply device; the drying air passes through the plate type discharge conveyor belt 2-2, the middle layer plate type conveyor belt 2-3 and the plate type feed conveyor belt 2-1 sequentially from bottom to top, drying Under the action of their diversion, the wind circulates in the furnace 4 in an S-shaped flow trajectory from bottom to top, and finally is discharged from the exhaust port on the top of the furnace 4;

When the sludge is transported into the furnace 4 through the plate feed conveyor belt 2-1, the sludge rolls down from the end of the plate feed conveyor belt 2-1 to the plate middle layer conveyor belt of the first layer, and then is transported by the first layer The end of the plate-type middle layer conveyor belt rolls down to the plate-type discharge conveyor belt 2-2 in turn, so that the sludge moves in the furnace 4 in an S-shaped track from top to bottom, and finally is sent out by the plate-type discharge conveyor belt 2-2.

The movement direction of the sludge in the furnace 4 is opposite to the flow direction of the drying wind in the furnace 4 .

The number of layers of the middle layer conveyor belt 2-3 is two or more layers, and the ends of the middle layer conveyor belts 2-3 of each layer are interlaced.

Between the plate feed conveyer belt 2-1, the middle plate conveyer belt 2-3 and the plate discharge conveyer belt 2-2, a deflector baffle 3 is added; on the wall.

The dry air supply device includes an absorption dehumidifier and a waste heat heater; air enters the waste heat heater from the absorption dehumidifier, and then is sent into the furnace 4 by the waste heat heater.

The exhaust port on the top of the furnace 4 is provided with a tail gas treatment device 1 , and the bottom of the furnace 4 is provided with a movable slag discharge plate 5 .

The tail gas treatment device 1 is a catalyst filter layer for filtering out harmful substances in the exhaust gas.

The wet sludge drying method combined with the waste heat utilization of thermal power plants in the present invention can be realized through the following steps:

Start the drying air supply device, and the drying air (with a temperature of 100°C to 150°C) enters the furnace 4 from the bottom side of the furnace 4;

The drying air passes through the plate discharge conveyor belt 2-2, the middle layer plate conveyor belt 2-3 and the plate feed conveyor belt 2-1 sequentially from bottom to top, and the drying wind forms an S shape from bottom to top under their diversion The flow trajectory is circuitous in the furnace 4, and finally discharged to the atmosphere through the exhaust port on the top of the furnace 4;

Start plate feed conveyer belt 2-1, plate discharge conveyer belt 2-2 and middle layer plate conveyer belt 2-3, make them run;

The sludge is placed on the plate feed conveyor belt 2-1, and is transported to the inner top of the furnace 4 by the plate feed conveyor belt 2-1, and the sludge is transported by the end of the plate feed conveyor belt 2-1 under the action of gravity Roll down to the first layer of the plate-type middle conveyor belt, and then continue to roll down from the end of the first layer of the plate-type middle layer conveyor belt to the next layer of the plate-type middle layer conveyor belt, so that the cycle is repeated; make the sludge from top to bottom The bottom moves in an S-shaped trajectory in the hearth 4, and gradually dries; this process prolongs the contact time and contact area between the sludge and the drying air in the hearth 4, so that the sludge is fully dried;

The dried sludge is finally sent out through the plate type discharge conveyor belt 2-2.

The supply process of the dry air supply device is as follows: the external air is first cooled and dehumidified by the evaporator, then the temperature is raised by the condenser to reduce its relative humidity, and then reheated by the waste heat heater using the waste heat of the flue gas of the thermal power plant to make it relatively Humidity further reduces, this moment passes in the furnace 4.

The whole drying process of the sludge in the present invention is highly efficient and energy-saving. On the one hand, it reduces the exhaust gas temperature of the thermal power plant and improves the energy utilization rate;

As described above, the present invention can be preferably carried out.

The implementation of the present invention is not limited by the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods, and are all included in within the protection scope of the present invention.

Claims (10)

1. A sludge drying device combined with thermal power plant waste heat utilization, characterized in that it includes a furnace (4), a plate feed conveyor belt (2-1) arranged on the upper part of the furnace (4), and a lower part of the furnace (4). The plate type discharge conveyor belt (2-2); Between the plate feed conveyor belt (2-1) and the plate discharge conveyor belt (2-2), there are multi-layer middle layer plate conveyor belts (2-3) interlacedly distributed from top to bottom; each layer of middle layer plate conveyor belts (2-3) space the internal airflow channels of the furnace (4) into S-shaped airflow channels; The lower side wall of the furnace (4) is provided with a drying air supply device; the drying air passes through the plate type discharge conveyor belt (2-2), the middle layer plate type conveyor belt (2-3) and the plate type feed conveyer successively from bottom to top. With (2-1), the drying wind, under their splitting action, flows roundabout in the furnace (4) in an S-shaped flow path from bottom to top, and finally is discharged from the exhaust port on the top of the furnace (4); When the sludge is conveyed into the furnace (4) through the apron feeding conveyor belt (2-1), the sludge rolls down from the end of the apron feeding conveyor belt (2-1) to the first layer of apron middle conveyor belt , and then roll down from the end of the plate-type middle layer conveyor belt on the first layer to the plate-type discharge conveyor belt (2-2), so that the sludge moves in the furnace (4) in an S-shaped trajectory from top to bottom, and finally is discharged from the plate type. Material conveyor belt (2-2) sends out. 2. According to claim 1, the combined thermal power plant waste heat utilization sludge drying device is characterized in that the movement direction of the sludge in the furnace (4) is opposite to the flow direction of the drying wind in the furnace (4). 3. According to claim 1, the combined thermal power plant waste heat utilization sludge drying device is characterized in that, the number of layers of the middle plate conveyor belt (2-3) is two layers or more than two layers, and the middle plate conveyor belt of each layer The ends of (2-3) are staggered with each other. 4. According to any one of claims 1 to 3, combined with thermal power plant waste heat utilization sludge drying device, it is characterized in that, in the plate feeding conveyor belt (2-1), the middle layer plate conveyor belt (2-3) and the plate type Between the discharge conveyor belts (2-2), there are additionally baffle baffles (3); the baffle baffles (3) are staggeredly distributed on the inner wall of the furnace (4). 5. According to claim 4, combined with thermal power plant waste heat utilization sludge drying device, it is characterized in that, the dry air supply device includes an absorption dehumidifier, a waste heat heater; air enters the waste heat heater from the absorption dehumidifier, and then It is sent into the furnace (4) by the waste heat heater. 6. According to claim 4, the combined thermal power plant waste heat utilization sludge drying device is characterized in that, the exhaust port on the top of the furnace (4) is provided with a tail gas treatment device (1), and the bottom of the furnace (4) is provided with a movable Slagging plate (5). 7. According to claim 4, the combined thermal power plant waste heat utilization sludge drying device is characterized in that the tail gas treatment device (1) is a catalyst filter layer for filtering harmful substances in the waste gas. 8. A wet sludge drying method combined with thermal power plant waste heat utilization, characterized in that it is realized by using the sludge drying device combined with thermal power plant waste heat utilization described in any one of claims 1 to 7, and the specific implementation steps are as follows: Step 1: Start the drying air supply device, and the drying air enters the furnace (4) from the bottom side of the furnace (4); The drying wind passes through the plate discharge conveyor belt (2-2), the middle layer plate conveyor belt (2-3) and the plate feed conveyor belt (2-1) successively from bottom to top. Bottom-to-up S-shaped flow trajectory in the hearth (4) circuitous flow, and finally discharged to the atmosphere from the top exhaust port of the hearth (4); Step 2: Start the plate type feeding conveyor belt (2-1), the plate type discharging conveyor belt (2-2) and the middle layer plate type conveyor belt (2-3) to make them run; The sludge is placed on the plate feed conveyor belt (2-1), and is transported to the inner top of the furnace (4) by the plate feed conveyor belt (2-1), and the sludge is transported by the plate feed conveyor belt (2-1 ), rolls down to the first layer of slatted middle conveyor belt under the action of gravity, and then continues to roll down from the end of the first layer of slatted middle layer conveyor belt to the next layer of slatted middle layer conveyor belt, so reciprocating Circulation; make the sludge move roundabout in the furnace (4) in an S-shaped track from top to bottom, and gradually dry; this process prolongs the contact time and contact area between the sludge and the drying wind in the furnace (4), so that The sludge is fully dried; The dried sludge is finally sent out through the plate discharge conveyor belt (2-2). 9. According to claim 8, the wet sludge drying method combined with waste heat utilization of thermal power plants is characterized in that, the supply process of the drying air supply device described in step 1 is as follows: The outside air is first cooled and dehumidified by the evaporator, and then the temperature is raised by the condenser to reduce the relative humidity, and then heated again by the waste heat heater using the waste heat of the flue gas of the thermal power plant to further reduce the relative humidity. At this time, it is passed into the furnace (4 )Inside. 10. The wet sludge drying method combined with waste heat utilization of thermal power plants according to claim 8, characterized in that the temperature of the drying air in step 1 is 100°C-150°C.