JPH0138208B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes the heat of the exhaust gas that accompanies the incineration of sludge, etc., which is discharged at the same time, by treating concentrated sludge, etc., which has been subjected to secondary treatment by microorganisms discharged in wastewater treatment facilities of sewage treatment plants and pulp mills. The present invention relates to a sludge treatment device using waste heat.

Traditionally, equipment for further processing sludge after secondary treatment, so-called tertiary treatment, involves adding a coagulant to the sludge to coagulate and precipitate it, then squeezing the precipitate with a dehydrator, then drying and incinerating it. However, this type has the disadvantage that not only does it increase the size of the device, but it also increases costs due to the addition of a flocculant. There is also the problem of odor during drying and incineration, and in order to solve this problem, the exhaust gas from the incinerator is passed through a dust collector, then heated again to about 750-800 degrees Celsius, and cleaned with a scrubber. However, not only does heating increase the processing cost, but the exhaust gas that has been cleaned by the scrubber is released directly into the atmosphere, and the thermal energy of the exhaust gas is not used effectively. I wasn't there.

In view of the above problems, the present invention aims to provide a sludge treatment device that can reduce treatment costs and efficiently utilize the thermal energy of exhaust gas, and includes an incinerator that incinerates sludge. and/or a spray dryer that humidifies exhaust gas from other incinerators such as municipal waste, a scrubber that washes the humidified exhaust gas with water to reduce its temperature, and saturates the water vapor.The exhaust gas after the scrubber is used as a heating source and concentrated as a liquid to be treated. The sludge heating system is equipped with a sludge heating can that introduces sludge and evaporates water in the sludge using the condensation heat of water vapor in the exhaust gas, and a deodorizing device that deodorizes the exhaust gas from the sludge heating can and releases it into the atmosphere. The present invention is characterized in that the sludge residue after the can is dried by adding moisture to the exhaust gas in the spray dryer and then incinerated in the incinerator.

Next, the present invention will be explained based on the drawings. FIG. 1 shows the layout of a sludge treatment apparatus according to the present invention. The incinerator 1 is equipped with an inlet 3 for receiving residue from a residue hopper 2, a burner 5 to which fuel is supplied from an oil service tank 4, and an air supply port 6 to supply air to the furnace 1. A hole 8 through which an exhaust gas passage 7 communicates is provided at the top of 1, and a hole 11 is provided at the lower end for sending generated ash to an ash transfer path 10 that sends the ash to an ash bunker 9. The exhaust gas passage 7 is a spray dryer 12
The spray dryer 12 is connected to the exhaust gas inlet 13 of the incinerator 1, and the upper part of the spray dryer 12 is provided with a nozzle 14 for spouting sludge residue, which will be described later.The lower end is connected to the exhaust gas inlet 13 of the incinerator 1. A conveyor 15 is provided. The exhaust gas outlet 16 of the dryer 12 communicates with the exhaust gas inlet 19 of the dry dust collector 18 via the exhaust gas passage 17, and the dust collected by the dust collector 18 from the exhaust gas is sent to ash through the outlet 18a with a valve at the lower end. aisle 10
It is now being discharged. An exhaust gas outlet 20 of the dust collector 18 communicates with a heating medium inlet 23 of a white smoke prevention heater 22 (heat exchanger) via an exhaust gas passage 21. The heating medium outlet 24 is connected to the exhaust gas passage 2
5 to the exhaust gas inlet 27 of the scrubber 26. The scrubber 26 is equipped with a circulation pump 30 that sends the cleaning water accumulated in the lower cleaning water reservoir 28 to the upper nozzle 29. (not shown) for processing. 31
is a potable soda tank, and potable soda is added to the washing water as needed by a pump 30'. An exhaust gas outlet 32 of the scrubber 26 communicates with a heating medium inlet 35 of a heating chamber 34 of a first heating can 33 (sludge heating tube) via an exhaust gas passage 36. An outlet 37 for water produced by condensation of water vapor in the exhaust gas is provided at the lower end of the heating chamber 34.
7 is connected to a condensed water inlet 38 of the scrubber 26 via a pipe 39. A heating medium outlet 40 of the heating chamber 34 communicates with an exhaust gas inlet 43 of a deodorizing device 42 via an exhaust gas passage 41. Inside the heating can 33, chambers 46 and 47 are formed above and below the heating chamber 34 by two partition walls 44 and 45. The upper chamber 46 is provided with a nozzle 48, which will be described later.
is connected to a lower chamber 47 via a number of pipes 49 extending inside the heating chamber 34 . On the other hand, the lower end of the deodorizing device 42 forms a condensed water tank 48, which stores water condensed from the exhaust gas cooled by a condenser 49. Water overflowing from the water tank 48 is sent to the general water treatment equipment mentioned above. The upper half of the deodorizing device 42 has a deodorizing function, and a deodorizing liquid tank 50 in which a deodorizing liquid made of a solution of sodium chloride, sodium hypochlorite, sodium thiosulfate, etc. is stored is connected to a pump 51. It communicates with the shower 52 via the shower. The exhaust gas rises through the hole 53, is deodorized as it passes through the porous contact material 54 to which the deodorizing liquid sprayed from the nozzle 52 is attached, and passes through the mist separator 55 that prevents the scattering of fine particles of the deodorizing liquid. The exhaust gas is then released from the exhaust gas outlet 56. The exhaust gas outlet 56 communicates with the heated medium inlet 57 of the white smoke prevention heater 22 via an exhaust gas passage 58, and through the heating chamber 59, the heated medium outlet 60, the exhaust gas passage 61, and the inlet 63 of the induced draft fan 62. It's communicating. Exhaust fan 62
The outlet 64 connects to the exhaust pipe 66 via an exhaust gas passage 65.
is connected to.

On the other hand, the sludge after the secondary treatment is stored in a sludge thickening tank 67 and sent to a pump 69 via a sludge passage 68.
The sludge is pumped up to the sludge receiving tank 70. 71 is a level switch, and the lower part of the sludge receiving tank 70 is a level switch.
It communicates with the nozzle 48 of the heating can 33 via a feed pump 72 and a sludge passage 73. The lower chamber 47 of the first heating can 33 has a sludge passage 74 at the lower end.
are in communication, and a steam passage 75 is in communication with the side wall. The sludge passage 74 is connected to a second heating can 33 similar to the first heating can 33 via a first stage pump 76.
The steam passage 75 communicates with the nozzle 48a of the first
It communicates with the mist separator 77. The liquid separated by the mist separator 77 is sent to the water tank 79 via the liquid passage 78, and the gas is sent to the heating medium inlet 35a of the second heating can 33a via the gas passage 80. A gas outlet 81 at the upper end of the heating chamber 34a communicates with a cooled medium inlet 84 of a third intercooler 83 via a gas passage 82, and a liquid outlet 85 at the lower end communicates with a water tank 79 via a liquid passage 86. ing. Second heating can 33
Similar to the first heating can 33, there are partition walls 44a and 45 in a.
a, chambers 46a, 47a, and a pipe 49a are provided, and similarly, a sludge passage 74 is provided in the lower chamber 47a.
a is in communication with the steam passage 75a. Sludge passage 7
4a has a second stage pump 76a in the middle,
The tip communicates with the nozzle 48b of the third heating can 33b. Further, the steam passage 75a communicates with a second mist separator 77a, a liquid passage 78a that sends the liquid separated by the mist separator 77a to a water tank 79, and a gas passage 80a that communicates with the heating medium inlet 35b of the third heating can 33b. It communicates with the mist separator 77a. Similar to the structure of the first and second heating cans 33 and 33a, the third heating can 33b is provided with partition walls 44b and 45b, chambers 46b and 47b, and a pipe 49b.
Similar to a, the gas outlet 81 at the upper end of the heating chamber 34b
a communicates with the cooled medium inlet 84a of the second intercooler 83a via the gas passage 82a, and the sludge passage 74b and the steam passage 75b communicate with the lower chamber 47b of the third heating can 33b.
The sludge passage 74b has a third stage pump 76 in the middle.
b, and the tip of the nozzle 48 is the fourth heating can 33c.
It is connected to c. The steam passage 75b also communicates with a third mist separator 77b, a liquid passage 78b that sends the liquid separated by the third mist separator 77b to a water tank 79, and a gas passage 80b that communicates with the heating medium inlet 35c of the fourth heating can 33c. are in communication with the mist separator 77b, respectively. Like the second and third heating cans 33a and 33b, the fourth heating can 33c includes a heating chamber 34c, partition walls 44c and 45c, chambers 46c and 47c, a pipe 49c and a heating chamber 34c.
It has a gas outlet 81b at the upper end.
1b communicates with a cooled medium inlet 84b of the first intercooler 83b via a gas passage 82b. Further, a sludge passage 74c and a steam passage 75c communicate with the lower chamber 47c, and the sludge passage 74c has a thickened sludge pump 87 in the middle, and its tip communicates with the nozzle 14 of the spray dryer 12. The steam passage 75c also communicates with a fourth mist separator 77c. The fourth mist separator 77c includes a fourth mist separator 77c.
A liquid passage 78c that sends the liquid separated by the mist separator 77c to a water tank 79 and a gas passage 80c that communicates with a gas inlet 89 of a barometric condenser 88 are in communication with each other. A water inlet 90 is provided at the upper end of the barometric condenser 88.
A gas outlet 91 is provided on the upper side wall, and a large number of fins 92 are provided on the inner wall of the condenser 88 to increase the contact area between the gas and the liquid. It's starting to flow down. Also capacitor 8
A drain port 93 is provided at the lower end of the cooling tower 95, and the drain port 93 communicates with a shower 96 of a cooling tower 95 via a hot well 94 for temporarily storing waste water. The cooling tower 95 has a cooling water tank 97 at the bottom, and the tank 97 has a supply water channel 98 and a cooling water pump 99 in the middle.
It is in communication with a cooling water channel 100 having a. The tip of the cooling water channel 100 is connected to the water supply port 90 of the barometric condenser 88 and the first intercooler 8.
It communicates with the cooling medium inlet 101 of 3b. Cooling medium outlet 102 of cooler 83b is connected to cooling water passage 1
03 to the cooling medium inlet 104 of the second intercooler 83a, and the cooler 83a
The cooling medium outlet 105 of the third intercooler 83 is connected to the cooling medium inlet 10 of the third intercooler 83 via the cooling water passage 106.
It is connected to 7. Each intercooler 83,8
Cooled medium outlets 108, 108 of 3a, 83b
a, 108b and barometric capacitor 8
The gas outlet 91 of 8 is connected to the air supply port 6 of the incinerator 1 via a vacuum pump 109 and a buffer tank 110.
Inlet 1 of the blower 111 that communicates with the air blower 111 and blows air.
It is connected to 12. Note that the water tank 79 communicates with the above-mentioned general water treatment equipment via a condensate pump 113.

Next, the effect will be explained. The residue is incinerated in the incinerator 1, and the generated ash is conveyed to the ash bunker 9 through an ash conveying passage 10. Exhaust gas from incinerator 1 (approx.
850°C) is humidified by coming into contact with the thickened sludge that is sent into the dryer 12 from the nozzle 14 through the process described later in the spray dryer 12. On the other hand, the thickened sludge is dried by the exhaust gas, and the dried sludge is sent to the inlet 3 of the incinerator 1 by the conveyor 15 and incinerated in the incinerator. After dust is removed from the exhaust gas (approximately 300°C) from the dryer 12 by the dry dust collector 18, the exhaust gas from the deodorizing device 42 (described later) is heated by the white smoke prevention heater 22 and sent to the scrubber 26. . The scrubber 26 is further humidified to a nearly saturated state by the cleaning water sprayed from the nozzle 29, and the cleaned exhaust gas (approximately 79°C) is introduced into the heating chamber 34 of the first heating can 33 as humid exhaust gas. Ru. In the heating can 34, the exhaust gas indirectly heats the thickened sludge (described later) flowing down inside the pipe 49 from outside the pipe 49. Due to this heating, the exhaust gas loses heat (mainly heat of condensation of water vapor) and becomes about 66°C and is introduced into the deodorizing device 42 through the passage 41. On the other hand, water generated by condensation is passed from the outlet 37 through the pipe 39 to the scrubber 26. will be returned to. The exhaust gas is dehumidified by a condenser 49 in the deodorizing device 42, and is further dehumidified by a contact agent 5 in the upper part.
After being deodorized by the deodorizing liquid when passing through the white smoke prevention heater 22 through the outlet 56 at the upper end. Note that the water flowing through the pipes of the condenser 49 is introduced from the cooling tower 95. The exhaust gas (approximately 36 degrees Celsius) introduced into the heater 22 is heated by heat exchange with the high temperature exhaust gas (approximately 300 degrees Celsius) from the exhaust gas passage 21, passes through an induced draft fan 62, and is released into the atmosphere from an exhaust stack 66. be done.

On the other hand, the thickened sludge pumped up from the sludge thickening tank 67 by the pump 69 and temporarily stored in the sludge receiving tank 70 is transferred to the first heating can 3 by the feed pump 72.
3 will be introduced. The concentrated sludge in the upper chamber 46 introduced from the nozzle 48 is heated by the heat of condensation of the water vapor in the exhaust gas as described above while flowing down the pipe 49, and a part of the sludge turns into steam and passes from the passage 75 to the first mist separator. Introduced in 77. Separator 7
The liquid portion of the steam introduced into the tank 7 is introduced into the water tank 79 via the passage 78, and the gas portion is introduced into the second heating can 3.
3a is introduced into the heating chamber 34a. The sludge whose water content has been reduced to some extent as steam is introduced into the chamber 46a of the second heating can 33a by the first stage pump 76. A portion of the vapor introduced into the heating chamber 34a of the second heating can 33a that is condensed into liquid is sent to the water tank 79 via the passage 86. The gaseous portion is cooled by the third intercooler 83 via the passage 82, then sucked by the vacuum pump 109, and sent into the incinerator 1 by the blower 111. The liquid sludge introduced into the chamber 46a from the nozzle 48a of the second heating can 33a is transferred to the pipe 49a.
A portion of the mist becomes steam while flowing down, and the steam portion is introduced into the second mist separator 77a from the passage 75a. The liquid portion of the vapor introduced into the separator 77a is introduced into the water tank 79 via the passage 78a,
The gas portion passes through the passage 80a to the third heating can 33b.
is introduced into the heating chamber 34b. The sludge in the lower chamber 47a with further reduced water content is introduced into the third heating can 33b by the second stage pump 76a.
Thereafter, the same process as in the second heating can 33a is repeated in the third heating can 33b and the fourth heating can 33c, and the gas portion separated from the sludge is sent to the vacuum pump 10 via the intercoolers 83a and 83b.
9 and sent into the incinerator 1 by the blower 111. The separated water is introduced into the water tank 79, and the remaining sludge residue is finally passed through the passage 74c.
is sent to the nozzle 14 of the spray dryer 12 by the thickened sludge pump 87. Furthermore, the gas portion finally separated by the fourth mist separator 77c is washed in the barometric condenser 88 by water circulating through the cooling tower 95.
It is sucked by the vacuum pump 109 and the blower 111
It is sent into the incinerator 1 by. The water circulated between the cooling tower 95 and the barometric condenser 88 by the cooling water pump 99 is also diverted after the pump 99 to the intercoolers 83, 83a, 83b.
First, it is introduced as a cooling medium into the first intercooler 83b, and then into the second and third intercoolers 83a, 83 as a cooling medium.

In addition, in the separation process in each heating can 33, 33a, 33b, 33c, the vacuum pump 109
Since the separation is carried out under reduced pressure, the boiling point is lowered and the evaporation efficiency is increased.

As explained above, according to the present invention, the concentrated sludge is treated using the heat of the exhaust gas from the sludge incinerator 1, so there is an advantage that the fuel cost required for sludge treatment is extremely low. Also, a scrubber 26 saturates the exhaust gas with water vapor, and a scrubber 2
A sludge heating can 33 is installed which uses the exhaust gas after 6 as a heat source, introduces thickened sludge as the liquid to be treated, and evaporates water in the sludge using the heat of condensation of water vapor in the exhaust gas, so that the low temperature of the thickened sludge can be reduced. Evaporation can be easily and stably performed. Furthermore, since a spray dryer 12 is provided that uses sludge residue to humidify the exhaust gas, humidification of the exhaust gas and drying of the sludge can be completed at the same time, and there is no need to spend fuel or the like to dry the sludge with the exhaust gas. It is economical.

In the embodiment, four heating cans are provided, but as long as at least the first heating can 33 is provided, any number of heating cans may be provided. In addition, in the embodiment, the high-temperature exhaust gas from the incinerator 1 is used in the white smoke prevention heater 22 to heat the deodorized and low-temperature exhaust gas, and then the exhaust gas is released into the atmosphere from the exhaust stack.
White smoke caused by water vapor in the exhaust gas condensing into minute water particles immediately after leaving the exhaust stack 66
It is possible to prevent further discharge, improve visibility, and improve the environment.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the layout of a sludge treatment apparatus according to the present invention. 1... Incinerator, 12... Spray dryer, 26... Scrubber, 33... Sludge heating can, 42... Deodorizing device.

Claims (1)

[Claims] 1. An incinerator that incinerates the residue, a spray dryer that humidifies the exhaust gas from the incinerator, a scrubber that washes the humidified exhaust gas with water to reduce its temperature, and saturates the water vapor. Equipped with a sludge heating can that introduces concentrated sludge as a liquid and evaporates water in the sludge using the heat of condensation of water vapor in the exhaust gas, and a deodorizing device that deodorizes the exhaust gas after leaving the sludge heating can and releases it into the atmosphere. A sludge treatment device using waste heat, characterized in that the sludge residue with reduced moisture after leaving the sludge heating can is dried by adding moisture to the exhaust gas in the spray dryer, and then incinerated in the incinerator.