JPH0227920Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is used in a sewage treatment equipment to cool the reaction liquid in a reaction tank in which a mixed liquid of undiluted raw water and returned sludge undergoes a biological reaction under the supply of air. related to a device for

[Prior art] As an oxidation reaction for sewage treatment, there is a method in which a mixed solution of undiluted raw water and returned sludge is reacted in a closed reaction tank under the supply of air, but in this case, the temperature rise due to the heat of reaction is significant. Since there is a risk that microorganisms contributing to the reaction may be killed, it becomes necessary to cool the reaction liquid.

Conventionally, there is a device as shown in FIG. 4 as a cooling means for the reaction liquid in this type of oxidation reaction tank.

In this device, a circulation path 4 which is led out from the bottom of a reaction tank 1 and is connected to an undiluted raw water inflow pipe 2 and a sludge return pipe 3 is connected to the reaction tank 1 via a liquid circulation pump 5 on the way.
The liquid drop tube 6 is connected to the upper end of a liquid drop tube 6 that protrudes high upward, and the liquid drop tube 6 has an air suction tube 7 connected to its upper end, and a lower end formed in a nozzle shape and opened above the liquid level in the reaction tank 1. ing. A cooling jacket 8 is fitted in the middle of the circulation path 4.
An evaporator of a refrigeration device 9 is incorporated in the refrigeration system 9 to cool the reaction liquid passing through the cooling jacket 8 position. 10 is a cooling tower of the refrigeration device 9.

When such a cooling means is used, the reaction liquid is only cooled from the outside of the circulation path 4 when it passes through the cooling jacket 8, resulting in poor heat exchange efficiency and the need for power to operate the refrigeration device 9. There's a problem.

In addition, there is a spiral heat exchanger that circulates fluids that exchange heat with each other in countercurrent flow through a spiral partition wall, but because a large number of pins are installed in the flow passages to maintain spacing, it is difficult to circulate wastewater. This was unsuitable because contaminants in the wastewater got entangled with the pins and blocked the flow path.

[Problem that the invention attempts to solve]

In view of the above-mentioned problems, the present invention attempts to cool the reaction liquid efficiently by using a spiral heat exchanger which has good heat exchange efficiency with the reaction liquid without using a refrigeration device.

[Means for solving problems]

This invention is based on a spiral heat exchanger that circulates and cools the reaction liquid in an oxidation reaction tank in which undiluted wastewater undergoes a microbial reaction while supplying air, and the reaction liquid and cooling water exchange heat through a partition wall. A plurality of spiral spacing bodies are formed in parallel to the flow direction in each of the liquid flow path and the cooling water flow path, and the reaction liquid in the reaction tank is directly exchanged heat with the cooling water using a spiral heat exchanger to improve cooling efficiency. In addition, by holding the flow passages of the spiral heat exchanger with a spacer parallel to the flow direction, the flow passages are prevented from being blocked by contaminants in the reaction liquid.

[Effect]

The present invention improves the cooling effect by cooling the reaction liquid in the oxidation reaction tank with a spiral heat exchanger, and the flow path of the spiral heat exchanger has a plurality of spiral spacers arranged parallel to the flow direction. The flow interval maintained by the flow rate is maintained, and impurities in the reaction solution are not entangled.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

Reference numeral 11 denotes a spiral heat exchanger, in which a reaction liquid flow passage 14 and a cooling water flow passage 15 are formed via spiral partition walls 12 and 13 formed by spirally winding two metal plates. Partition walls 12, 13
Both ends hermetically seal the end faces fitted into spiral grooves 18 and 19 formed in the end plates 16 and 17, while maintaining the distance between the flow passages 14 and 15. Furthermore, a plurality of spiral spacing members 20 and 21 are provided in the flow passages 14 and 15 at appropriate intervals in the axial direction in parallel to the flow direction.

Furthermore, an introduction pipe 23 having a reaction liquid inlet 27 opened at one end is inserted into the inner end of the reaction liquid flow passage 14 in the axial direction, and a large number of through holes 22 opened on the circumferential surface are communicated with the reaction liquid flow passage 14. A reaction liquid return port 24 is opened at the outer end of the reaction liquid flow passage 14 .

Furthermore, a cooling water inlet 25 is opened at the outer end of the cooling water flow passage 15, and the inner end is communicated with a cooling water return port 26 opened at one end plate 17.

In addition, at both the outer and inner ends of the flow passages 14 and 15, portions where the spacing members 20 and 21 are not provided are left so that the reaction liquid and the cooling water can flow in the axial direction.

Next, reference numeral 28 denotes a reaction tank, which is partitioned from top to bottom by a partition plate 29 that leaves a flow path around it, and a raw water introduction pipe 30 into which undiluted raw human waste water is introduced is connected to the bottom, and a liquid circulation pump 31 is connected in the middle. A circulation path 32 having
is led out from the bottom, and this circulation path 32 is communicated with the upper end of a liquid flow down pipe 33 that projects high upward. The liquid flow down pipe 33 narrows downward in the shape of a nozzle, and its lower end is opened above the liquid level in the reaction tank 28, and its upper end is communicated with an air suction pipe 34.

Further, a sludge return pipe 35 is communicated in the middle of the circulation path 32.

A reaction liquid inlet pipe 36 led out from the liquid in the reaction tank 28 is communicated with the liquid inlet 27 of the spiral heat exchanger 11 via a liquid pump 37 on the way, and the reaction liquid of this heat exchanger 11 is returned. A reaction liquid return pipe 38 led out from the port 24 is communicated with the reaction tank 28 .

Further, the cooling water inlet 25 and the cooling water return port 26 of the spiral heat exchanger 11 are connected to the cooling water delivery pipe 3, respectively.
9. It is connected to a cooling tower 41 via a cooling water return pipe 40 so that cooling water can be circulated.

Next, the operation of the above embodiment will be explained.

Inside the reaction tank 28, a reaction liquid consisting of a mixture of undiluted raw human waste water and returned sludge is forcibly circulated while sucking air, and the upper part of the partition plate is divided into a nitrification part and the lower part is a denitrification part, and the liquid is dropped from above. The upper part is stirred by the circulating flow, and BOD removal occurs in the upper part and the denitrification reaction progresses in the oxidation part. At this time, the temperature of the liquid increases as the reaction progresses, but a part of the liquid is drawn out and introduced into the spiral heat exchanger 11, and the cooling tower 4
Since the water is cooled by the cooling water cooled in step 1 and returned to the reaction tank 28, the temperature inside the reaction tank 28 is prevented from rising.

Further, since the interval between the flow paths 14 and 15 is maintained by the interval holders 20 and 21 parallel to the flow direction, the interval holders 20 and 21 for contaminants in the flowing reaction liquid are maintained.
0 and 21, and smooth distribution is achieved.

[Effect of idea]

According to the present invention, in a spiral heat exchanger that cools undiluted wastewater by circulating a reaction liquid in an oxidation reaction tank in which a microbial reaction is caused while supplying air,
Since a plurality of spiral spacers are formed in parallel to the flow direction in the reaction liquid flow passage and the cooling water flow passage in which the reaction liquid and the cooling water exchange heat through the partition wall,
The reaction liquid in the reaction tank exchanges heat directly with the cooling water in a spiral heat exchanger in countercurrent flow, allowing for efficient cooling.The cooling water can be cooled by a cooling tower without using a refrigeration device as a cold heat source. That alone is enough. No need for refrigeration equipment,
Furthermore, the power cost for operating the refrigerator becomes unnecessary. moreover,
The distance between the reaction liquid flow path and the cooling water flow path of a spiral heat exchanger is maintained by a spiral spacer that is parallel to the flow direction, so the reaction liquid flow path is maintained in a space between the reaction liquid flow path and the cooling water flow path. There is no risk of foreign objects getting tangled, and clogging of the flow path is prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional perspective view of a reaction liquid cooling device showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional side view of the same, and 3.
The figure is a flow sheet of the present invention using the same device as above, and FIG. 4 is a flow sheet showing a conventional example. 11... Spiral type heat exchanger, 14... Reaction liquid flow path, 5... Cooling water flow path, 20, 21...
Spacer, 28...reaction tank.

Claims (1)

[Scope of utility model registration request] In a spiral heat exchanger that circulates and cools the reaction liquid in an oxidation reaction tank where undiluted wastewater is supplied with air and subjected to a microbial reaction, the reaction liquid flow path where the reaction liquid and cooling water exchange heat through a partition wall. A reaction liquid cooling device for a waste water oxidation reaction tank, characterized in that a plurality of spiral spacers are formed in parallel to the flow direction in each of the cooling water flow passages.