JPH0351967B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes the heat of the exhaust gas accompanying 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 sewage treatment plants and wastewater treatment facilities for pulp improvement. 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 flocculant to the sludge to coagulate it, squeezing it with a dehydrator, then drying it.
An incineration type is known, but this type has the disadvantage of increasing the size of the equipment and increasing costs due to the addition of agglomerate. 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-mentioned problems, the present invention aims to reduce treatment costs, effectively utilize the thermal energy of exhaust gas to perform treatment efficiently, and eliminate the need for a deodorizing device and a flocculant.

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 in the neck portion of 1, and a hole 11 is provided in the lower end to send the generated ash to an ash transfer path 10 that sends the ash to an ash bunker 9. . The exhaust gas passage 7 communicates with the heating medium inlet 13 of the air heater 12, and
The heating medium outlet 14 of is connected via the exhaust gas passage 17 to
Exhaust gas inlet 19 of cyclone type dry dust collector 18
The dust collected by the dust collector 18 from the exhaust gas is discharged into the ash passage 10 through a valved discharge port 18a at the lower end. Dust collector 1
The ash gas outlet 20 of No. 8 communicates with the exhaust gas inlet 27 of the scrubber 26 via the exhaust gas passage 21.
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, and the overthrown waste liquid from the cleaning water reservoir 28 is collected in a general water treatment equipment ( (not shown) for processing. Reference numeral 31 denotes a soluble soda tank, in which soluble soda is appropriately added to the washing water 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. Heating chamber 34
An outlet 37 for water produced by condensing water vapor in the exhaust gas is provided at the lower end of the scrubber 26 , and the outlet 37 communicates with 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 inlet 63 of an induced draft fan 62 via an exhaust gas passage 41 . An outlet 64 of the exhaust fan 62 communicates with an exhaust pipe 66 via an exhaust gas passage 65.

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 37. The lower chamber 47 of the first heating can 33 has a sludge passage 74 at the lower end.
are in communication, and the 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 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 sludge passage 74 via the liquid passage 78, and the gas is sent to the gas passage 8.
0 to the heating medium inlet 35 of the second heating can 33a
It is now sent to a. The gas outlet 81 at the upper end of the heating chamber 34a communicates with the cooled medium inlet 84 of the third intercooler 83 via the gas passage 82, and the liquid outlet 85 at the lower end communicates with the liquid passage 8.
It communicates with a water tank 79 via 6. Similar to the first heating can 33, the second heating can 33a has a partition wall 44a,
45a, chambers 46a, 47a, and a pipe 49a, 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. The vapor passage 75a also communicates with a second mist separator 77a, and is a liquid passage 7 that sends the liquid separated by the mist separator 77a to the sludge passage 74a.
8a and the heating medium inlet 35 of the third heating can 33b
Each of the gas passages 80a communicating with the mist separator 77a communicates with the mist separator 77a. Third heating can 33
Similar to the structure of the first and second heating cans 33 and 33a, partition walls 44b and 45b, chambers 46b and 47b,
A pipe 49b is provided, and the second heating can 3
3a, the gas outlet 8 at the upper end of the heating chamber 34b
1a 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 communicates with 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 the sludge passage 74b, and a gas passage connected to the heating medium inlet 35c of the fourth heating can 33c. 80b are in communication with the mist separator 77b, respectively.
The fourth heating can 33c is the second and third heating cans 33a, 3
3b, heating chamber 34c, partition walls 44c, 45
c, chambers 46c, 47c, and a gas outlet 81b at the upper end of the pipe 49c, and the gas outlet 81b is connected to the first intercooler 83b via a gas passage 82b.
It communicates with the cooled medium inlet 84b. In addition, the lower chamber 47c has a sludge passage 74c and a steam passage 75c.
The sludge passage 74c has a thickened sludge pump 87 in the middle, and the tip thereof communicates with an oxidation reaction tower 42, which will be described later. 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 to the sludge passage 74c and a barometric condenser 88.
Gas passages 80c that communicate with the gas inlets 89 of the two are in communication with each other. A water inlet 90 is provided at the upper end of the barometric condenser 88, and a gas outlet 91 is provided at 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 gas and liquid. , water supply port 90
Water flows down through the fins 92. A drain port 93 is provided at the lower end of the condenser 88, and the drain port 93 is connected to a cooling tower 95 via a hot well 94 for temporarily storing waste water.
It communicates with the shower 96. The cooling tower 95 has a cooling water tank 97 at the bottom, and the tank 97 has a supply water channel 9.
8 and a cooling water channel 1 having a cooling water pump 99 in the middle.
00 is in communication. The tip of the cooling water channel 100 communicates with a water supply port 90 of the barometric condenser 88 and a cooling medium inlet 101 of the first intercooler 83b. The coolant outlet 102 of the cooler 38b communicates with the coolant inlet 104 of the second intercooler 83a via the coolant passage 103, and the coolant outlet 102 of the cooler 83a communicates with the coolant inlet 104 of the second intercooler 83a.
5 communicates with a cooling medium inlet 107 of the third intercooler 83 via a cooling water passage 106.
The cooled medium outlets 108, 108a, 108b of each intercooler 83, 83a, 83b and the gas outlet 91 of the bimetric condenser 88 are connected to the air supply port 6 of the incinerator 1 via a vacuum pump 109 and a water seal tank 110. It communicates with an inlet 112 of a blower 111 that blows air.

On the other hand, the oxidation reaction tower 42 to which thickened sludge is supplied by the thickened sludge pump 87 is further communicated with a high-temperature air inlet passage 43 . The upstream end of the passage 43 communicates with the heated medium outlet 15 of the air heater 12, and the heated medium inlet 16 of the heater 12 communicates with the blower 51 via the air passage 50. The cracked gas or/and air after indirect heating outlet 52 of the reaction tower 42 communicates with the inlet 112 of the blower 111 via a passage 53 . Further, the residue outlet 59 of the reaction column 42 communicates with a dehydrator 55 via a passage 54. The dehydrated cake dehydrated by the dehydrator 55 is conveyed to the inlet 3 of the incinerator 1 via a passage 57 having a dehydrated cake pump 56 in the middle, and the dehydrated liquid is conveyed through a passage 58 (not shown). It is now being sent to general water treatment facilities for treatment. The water tank 79 also has a condensate pump 1.
13, it communicates with the above-mentioned general water treatment equipment.

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.
800℃), blower 5 is used in air heater 12.
After heating the air from 1 to reduce the temperature to 650 to 750°C, a dry dust collector 18 removes dust. Dust collector 1
The exhaust gas No. 8 is sent to the scrubber 26, and is further humidified to a nearly saturated state by the cleaning water sprayed from the nozzle 29 inside the scrubber 26, and the cleaned exhaust gas (approximately 80° C.) becomes humid exhaust gas. and introduced into the heating chamber 34 of the first heating can 33. In the heating chamber 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 is introduced into the passage 41 at a temperature of approximately 65 to 70°C, while water generated by condensation is passed from the outlet 37 through the pipe 39 to the scrubber 2.
It will be returned to 6. The exhaust gas discharged from the outlet 40 passes through an induced exhaust fan 62 and is discharged into the atmosphere from a waste pipe 66.

On the other hand, the concentrated sludge assembled from the sludge thickening tank 67 by the pump 69 and once 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
A liquid portion of the vapor introduced into the sludge passage 74 is introduced into the sludge passage 74 via a passage 78, and a gas portion is introduced into the heating can 34a of the second heating can 33a. 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 charged into the incinerator 1 by the blower 111. Nozzle 48a of second heating can 33a
A portion of the liquid sludge introduced into the chamber 46a becomes steam while flowing down inside the pipe 49a, 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 passes through the passage 78a to the sludge passage 74a.
the gaseous portion is introduced into the third via passage 80a.
It is introduced into the heating chamber 34b of the heating can 33b. The sludge in the lower chamber 47a whose water content has further decreased is transferred to the second chamber 47a.
It is introduced into the third heating can 33b by the 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 part separated from the sludge is sucked by the vacuum pump 109 via the square intercoolers 83a and 83b and sent to the blower. 111, it is charged into the incinerator 1. Most of the separated moisture is used as heat and becomes condensed water and introduced into the hydrogen 79, and the remaining concentrated sludge is finally sent to the oxidation reaction tower 4 through the passage 74c by the concentrated sludge pump 87.
Sent to 2.

Further, the gas portion finally separated by the fourth mist separator 77c is cooled in the barometric condenser 88 by water circulating through the cooling tower 95, and becomes condensed water. The non-condensable gas is sucked by the vacuum pump 109 and sent into the incinerator 1 by the blower 111. The water circulated by the cooling water pump 99 between the cooling tower 95 and the barometric condenser 88 is also diverted after the pump 99 to the intercoolers 83, 83a, 83b, and is first introduced as a cooling medium into the first intercooler 83b, and then into the first intercooler 83b. 2. Third intercooler 83
a, 83 as a cooling medium.

On the other hand, the oxidation reaction tower 42 to which the concentrated sludge is supplied by the concentrated sludge pump 87 is further supplied with high-temperature air (450 to 500° C.) from the blower 51 which has obtained heat from the exhaust gas by the air heater 12. In the reaction tower 42, the thickened sludge is indirectly heated with high-temperature air and then exposed to a portion of air to oxidize and decompose a portion of the organic material, resulting in decomposed gas or Air is supplied to the incinerator 1 through the passage 53. In the incinerator 1, the decomposed gas is further oxidized and decomposed at a high temperature, and the deodorized air used for indirect heating is used as combustion air. Reaction tower 42
The resulting residue is dehydrated in a dehydrator 55, the dehydrated cake is burned in the incinerator 1, and the dehydrated liquid is processed through a passage 58 in a water treatment facility (not shown).

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 hardened and the evaporation efficiency is increased. Further, although the exhaust gas from the incinerator 1 undergoes heat exchange, it does not come into contact with or mix with the odor-containing concentrated sludge, so the exhaust gas can be discharged into the atmosphere without the need for a special deodorizing device.

As explained above, according to the present invention, the incinerator 1 for incinerating the residue is provided; the scrubber 26 for washing the exhaust gas from the incinerator 1 to cool it down with water and saturating the water vapor;
A sludge heating can 33 is provided which uses the exhaust gas after the scrubber 26 as a heat source, introduces concentrated sludge as a liquid to be treated, and evaporates water in the sludge using the heat of condensation of water vapor in the exhaust gas; An air heater 12 for heat exchange is provided between the furnace 1 and the scrubber 26. An oxidation reaction tower 42 is installed to oxidize and decompose the thickened sludge after the sludge heating can 33 using high-temperature air obtained from exhaust gas by the air heater 12. Since the sludge from the oxidation reaction tower 42 is incinerated in the incinerator 1 together with the cracked gas from the oxidation reaction tower 42 either directly or via the dehydrator 55, the following effects can be expected.

(a) Since the heat of the exhaust gas from the residue incinerator 1 is used to treat the thickened sludge, the fuel cost required for sludge treatment is extremely low (the dehydration rate of the dehydrator is improved, and the amount of water in the sludge is reduced). (because organic substances are thermally solidified).

(b) Scrubber 26 that saturates exhaust gas with water vapor
And the exhaust gas after the scrubber 26 is used as a heating source,
Thickened sludge is introduced as the liquid to be treated, and the sludge heating can 33 is installed to evaporate water in the sludge using the heat of condensation of water vapor in the exhaust gas, so that the low-temperature evaporation of the thickened sludge can be easily stabilized and the sludge can be heated. The concentration efficiency can be increased more quickly.

(c) Since the concentrated sludge, etc. containing odor from the sludge heating can 33 does not come into contact with the exhaust gas from the incinerator 1, odor substances will not be mixed into the exhaust gas, and a deodorizing device for the exhaust gas can be installed. There is no need for special provision. Therefore, the device can be made more compact and lower in price.

Note that in carrying out the present invention, the following configuration may be used.

() In the above 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.

() The dehydrator 55 may be omitted and the residue from the oxidation reaction tower 42 may be directly supplied to the incinerator 1. However, in this case, a decrease in combustion efficiency is unavoidable.

[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... Air heater, 26... Scrubber, 33... Sludge heating can, 42... Oxidation reaction tower, 55... Dehydrator.

Claims (1)

[Claims] 1 An incinerator is installed to cool the residue; a scrubber is installed to wash the exhaust gas from the incinerator to reduce its temperature and saturate the water vapor; the exhaust gas after the scrubber is used as a heating source, and concentrated sludge is introduced as the liquid to be treated, and the exhaust gas is A sludge heating can is installed to evaporate water in the sludge using the condensation heat of the water vapor inside; an air heater is installed to exchange heat between the incinerator and the scrubber:
An oxidation reaction tower is installed to oxidize and decompose the concentrated sludge after the sludge heating can using high-temperature air obtained from exhaust gas using an air heater; A sludge treatment device using waste heat, characterized in that the sludge is incinerated in the incinerator.