JPH02214599A - Method for drying water-containing solid - Google Patents

Abstract

PURPOSE:To eliminate the need for a fuel such as heavy oil by using a heat pump to recover the heat retained by waste water generated from a sewerage, heating air with the heat and drying a water-contg. solid generated from the sewerage with the heated air. CONSTITUTION:The water discharged from the sewerage is transiently charged into a pool 22. A pipe is arranged in the pool 22, and a heating medium I such as water in the pipe is circulated through a heat exchanger 24 by a pump 23. A heating medium II such as fluorocarbons is passed through the heat exchanger 24, and the heat of the discharged water is transmitted to the heating medium II from the heating medium I. The heating medium II is compressed by a compressor 25, and the air circulating through the pipes 29 and 30 connected to a predrying chamber 28 is heated in a condenser 26, and the water-contg. dirt is produced by the heated air. The dirt is completely dried in a high-temp. drying chamber 31 into which the waste gas from an incinerator 32 using dry sludge is introduced. Accordingly, another heat source such as heavy oil can be dispensed with.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for drying water-containing solids that effectively utilizes the heat possessed by sewage treatment wastewater.

[Prior Art] An outline of current sewage treatment equipment is shown in Figure 2. As shown in the figure, lη water discharged from household kitchens, bathrooms, flush toilets, etc. is collected in a settling basin 10. After the easily settled dust and earth are removed, the sludge first goes to a sedimentation tank 11, where small pieces of settled raw sludge are scraped up by a machine and collected in a thickening tank 12.

On the other hand, the sewage from which the settled sludge has been removed is aerated with activated sludge mixed in in the aeration tank 13 and decomposed by microorganisms, the settled sewage is removed in the final settling tank 14, and the sewage is sterilized with chlorine in the sterilization tank 15. , are discharged into the sea.

On the other hand, the first settling tank 11 aeration tank 13 and the final settling tank 1
The sludge collected in step 4 is concentrated in a thickening tank 12, and then transported to a first digestion tank 16 and a second digestion tank 17, where it is decomposed into gas and digested sludge.The gas is collected in a gas tank 18, and the digested sludge is After passing through the sludge storage tank 19, the dewatering equipment 2
After being dehydrated by 0, it is discharged as water-containing sludge.

[Problem that the invention seeks to solve]

However, the temperature of the waste water discharged from the sterilization pond 15 is around 12 degrees Celsius even in the middle of winter, and although it is a sufficient heat source, it is not used, and in some cases, there are problems such as the heated waste water becoming a source of pollution. was causing it.

In addition, in the above-mentioned first and second digestion tanks 16.17, since ordinary anaerobic bacteria are used, it is necessary to maintain the temperature at a high temperature to promote the reaction. The structure is such that the gas is temporarily stored in the gas tank 18 and then combusted by the boiler equipment 21 to generate steam, which is then sent to the digestion tank 16, 17 and heated, so that the generated gas (mainly methane gas) is The problem was that it was not being used effectively.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a sewage treatment facility that effectively utilizes the heat contained in the waste water generated in the sewage treatment facility.

[Means for solving problems]

The method for drying water-containing solids according to claim 1, which meets the above object, uses a heat pump to recover the retained heat of wastewater generated from sewage treatment equipment, and uses the recovered heat to heat the air. The heated air is configured to dry water-containing solids generated from the sewage treatment equipment.

The method for drying a water-containing solid material according to claim 2 is the method for drying a water-containing solid material according to claim 1, wherein the power source of the heat pump is fueled by gas generated from a sewage treatment facility. It consists of a heat engine such as a gas turbine or gas engine.

[Effect]

In the method for drying hydrated solids according to claim 1, heat of waste water generated from sewage treatment equipment is recovered by a heat pump, air is heated by this heat, and hydrated solids are dried by the air. are doing.

In the method for drying a water-containing solid material as set forth in claim 2, the power source of the heat pump is constituted by a heat engine that uses gas generated from sewage treatment equipment as fuel. Therefore, no extra power is required.

〔Example〕

Next, embodiments embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.

Here, FIG. 1 is a block diagram showing a schematic configuration of an apparatus to which a method for drying a water-containing solid material according to an embodiment of the present invention is applied.

As shown in FIG. 1, first, the discharged water discharged from the sterilization pond 15 shown in FIG. 1 is once put into the heat exchange pool 22 and then discharged.

A heat exchange pipe is arranged in the pool 22, and a heat medium such as water is pumped into the pool 22 by a pump 23 to another heat exchanger 24.
It is designed to circulate between

In the heat exchanger 24, a heat medium such as fluorocarbon is circulated, and the heat of the discharged water stored in the pool 22 is transferred to the heat medium 1 such as water, and from the heat medium I such as water. The heat is transferred to the heat medium (2) such as the above-mentioned Freon.

The heat medium (1) is pressurized by the compressor 25, heats the air in the pre-drying chamber by the condenser 26, returns to the heat exchanger 24 via the expansion valve 27, cools it, and absorbs heat. Note that the heat exchanger 24, compressor 25, condenser 26, and expansion valve 27 constitute a heat pump.

On the other hand, in the condenser 26, the air circulating through the vibrator 29.30 connected to the pre-drying chamber 28, which is an example of a drying chamber, is heated to about 60 to 80 degrees Celsius, and the air is heated to approximately 60 to 80 degrees Celsius. Water-containing waste (also referred to as dehydrated sludge), which is an example of water-containing solids discharged from the above-mentioned dewatering equipment 20, is pre-dried.

As a means for this pre-drying, for example, the water-containing waste may be exposed to hot air while being gradually conveyed by a hair dryer, or the water-containing waste may be gradually dropped from a direction facing the airflow.

Thereafter, the sludge from which some moisture has been removed in the pre-drying chamber 28 is sent to the high-temperature drying chamber 31. This high temperature drying room 31
Exhaust gas from the incinerator 32 is introduced into the
It is designed to be completely dried using high-temperature gas at ℃.

On the other hand, a part of the sludge completely dried in the high-temperature drying chamber 31 is used as fuel for the incinerator 32, and the other dried sludge is used as fertilizer or other fuel.

In this case, if the sludge is to be used as another fuel, the pre-dried sludge may be placed in a certain mold and shaped, and then placed in the high-temperature drying chamber 31. Furthermore, when used as fertilizer, it is also possible to mix the sludge discharged from the high temperature drying chamber 31 with the ash discharged from the incinerator 32. Although it is possible to directly insert a heat exchange pipe into the boule 22 to heat a heat medium made of chlorofluorocarbon or the like, A heat exchange pipe is placed in the sterilization chamber 15,
It is also possible to omit the Boolean 22 described above.

It is also possible to rotate the compressor of the heat medium (1) by a turbine or gas engine that uses methane gas stored in the gas tank 18 as fuel, as shown in FIG. hot air fan 3
It is also possible to rotate the rotational drive source No. 3 with a heat engine such as a turbine or an engine that uses the above gas as fuel.

Note that the exhaust gas from the high temperature drying chamber 31 is transferred to the incinerator 3.
It can be used as a heat source for the preheated air in step 2, or it can be used as a heat source to further raise the temperature of the air sent to the pre-drying chamber 28. When a heat engine using the above gas as fuel is used. In this case, it is possible to effectively utilize the heat possessed by the exhaust gas and the heat possessed by the cooling water of the engine as other heat sources.

By configuring as described above, the temperature of the wastewater discharged from the pool 22 is slightly lowered. Furthermore, after the preliminary drying, a heater that emits far infrared rays using the gas as fuel is provided, and the drying process is performed by the heater. It is also possible to provide a machine.

〔Effect of the invention〕

As is clear from the above description, the method for drying water-containing solids according to claim 1 effectively utilizes the heat of discharged water generated from sewage treatment equipment to dry water-containing solids. Therefore, conventional fuel such as heavy oil is not required.

Furthermore, the temperature of wastewater from sewage treatment equipment decreases,
This eliminates the problem of hot water drainage.

In the method for drying a water-containing solid material as set forth in claim 2, since the heat pump is rotationally driven by a heat engine that uses gas generated from the sewage treatment equipment as fuel, the heat pump is rotated by a heat engine that uses gas generated from the sewage treatment equipment as fuel, so that it is possible to use more external fuel, etc. Alternatively, equipment can be operated without using electricity or the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an apparatus to which the method for drying water-containing solids according to the present invention is applied, and FIG. 2 is a schematic block diagram of a conventional sewage treatment facility. [Explanation of symbols]

Claims (2)

[Claims] (1) Use a heat pump to recover the retained heat of the wastewater generated from the sewage treatment equipment, heat the air with the recovered heat, and use the heated air to remove the hydrated solids generated from the sewage treatment equipment. A method for drying a water-containing solid material. (2) The method for drying water-containing solids according to claim 1, wherein the power source of the heat pump is a heat engine that uses gas generated from sewage treatment equipment as fuel.