JPH10103862A - Superheater for water vapor recompression type vacuum drying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fully demonstrate capacity of a compressor sufficiently by a method wherein steam of saturated condition in a vacuum tank is heated by the suction pipe of the compressor to eliminate the wet condition of the steam and obtain superheated condition. SOLUTION: When the motor 2m of a compressor 2 is started and the operation of a drying device is started, steam is generated in a vacuum tank 1 and the steam becomes saturated condition whereby the suction steam of the suction pipe 6a becomes saturated condition. However, the switch 13 of a heater 11 for the suction pipe 6a is put ON, the suction pipe 6a is heated by a coil heater 11 and, accordingly, sucked steam is heated whereby the condensation of the steam can be prevented. In this case, when the suction pipe 6a is heated to a temperature higher than the saturation temperature of the steam, the suction steam is heated to superheated condition and it is preferable. The suction pipeline 6a is made as short as possible and the outer periphery is insulated whereby the capacity of a heat source can be a small. According to this method, the volume efficiency of the steam compressor can be maintained and the size and weight of the superheater can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a steam recompression vacuum drying apparatus used for dehydration and drying of water-containing waste, for example, raw garbage, waste fish and sludge, and concentration of waste liquid.

[0002]

2. Description of the Related Art Conventionally, wastes containing a large amount of water cannot be incinerated as they are and are liable to rot. In plating wastewater and photographic wastewater,
Due to the difficulty of disposal, ocean dumping is also being carried out, but this is being banned internationally.

[0003] Even flammable wastes containing a large amount of water can be incinerated with a small amount of a combustion aid by evaporating the water and reducing the water content, and those that self-burn can be used as an energy source.

[0004] Conventionally, techniques for drying hydrated waste by vacuuming have been put into practical use, and these techniques reduce the pressure of the airtight container containing the waste with a vacuum pump and simultaneously use hot water from a boiler. Alternatively, the vacuum vessel is heated by steam to evaporate water therein. The generated steam is condensed by the cooling water from the cooling tower and drained by a water ring type vacuum pump.

On the other hand, as a technique for reducing heat energy required for evaporation, a multi-stage flash technique and a vapor recompression technique have been conventionally known. In each of the techniques, the evaporated water vapor is compressed and condensed in a heat exchanger, and the latent heat of condensation at that time is used for evaporating water. In principle, high energy efficiency is possible.

[0006]

However, the steam to be recompressed here is often saturated, and is cooled while passing through the intake pipe of the steam compressor, and a part of the steam is liquefied to form fine particles. , And re-evaporates during the suction stroke, thereby reducing the volumetric efficiency of the compressor.

Accordingly, an object of the present invention is to provide a superheater of a steam recompression vacuum drying apparatus which can maintain the volumetric efficiency of a steam compressor and can be reduced in size and weight.

[0008]

According to the present invention, there is provided a vacuum tank for storing waste, a steam compressor for compressing steam from the vacuum tank, and a steam tank provided in the vacuum tank and thermally connected to the tank. Steam condenser, non-condensable gas discharging means for spontaneously discharging non-condensable gas from the steam condenser, and condensed water discharging means for spontaneously discharging condensed water from the steam condenser. An intake air heating device for heating the intake air is provided in an intake pipe of the steam compressor.

According to the present invention, the intake heating device is an electric heater provided in an intake pipe.

According to the present invention, the intake air heating device is a heat exchanger that uses steam discharged from the steam compressor provided in an intake pipe as a heat source.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a water-containing waste W is charged into a vacuum tank 1 and a condenser 3 is contained in the tank 1.
Is installed. One end 3a of the condenser 3 is connected to the steam compressor 2 by a steam pipe 6b, the other end 3b is a relief valve 4 for discharging non-condensable gas by a gas pipe 6c, and a steam for discharging condensed water by a drain pipe 6d. Each is connected to a trap 5.

An intake pipe 6a of the compressor 2 driven by the electric motor 2m is connected to the vacuum tank 1. A heater coil 11 serving as an intake heating device is wound around the intake pipe 6a, and the heater coil is connected to a power supply 12 via a switch 13.

Here, reference symbol E indicates a waste input port, and F indicates a waste output port.

The operation will be described below.

When the motor 2m of the compressor 2 is turned on and the drying device starts operating, steam is generated in the vacuum tank 1 and the steam is saturated, so that the intake air of the intake pipe 6a is also saturated. Turns into steam. However, when the switch 13 of the heater 11 of the intake pipe 6a is turned on, the coil heater 11
, The intake pipe 6a is heated, so that the inhaled steam is heated, and the steam is prevented from being condensed.
In this case, it is preferable to heat the intake pipe to a temperature equal to or higher than the saturation temperature, since the intake steam is overheated (superheated).

The intake pipe 6a is made as short as possible.
If the outer periphery is insulated, the heat source can have a small capacity.

FIG. 2 shows another embodiment of the present invention.
A heat exchanger 15 is provided in place of the electric heater.
That is, the steam pipe 6b on the discharge side of the compressor is connected to one end 15a of the double-pipe heat exchanger 15 provided in the intake pipe 6a of the compressor 2.
And the other end 15b is connected to one end 3a of the condenser 3, and the other components are configured in the same manner as in FIG.

Since there is no need to provide a separate heat source, there is also an advantage that maintenance and management are easy and operation costs are reduced.

The heat exchanger is not limited to the double tube type, but may be a shell and tube type or the like.

It has been experimentally confirmed that the volume efficiency of the steam compressor is improved by heating the intake pipe.

[0022]

The present invention is configured as described above,
Since the saturated steam in the vacuum tank is heated by the suction pipe of the compressor, the wet condition of the steam is eliminated and the superheated (superheat) condition allows the compressor to fully demonstrate its performance. Becomes

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a steam recompression type vacuum drying apparatus showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum tank 2 ... Steam compressor 3 ... Condenser 4 ... Relief valve 5 ... Steam trap 11 ... Coil heater 13 ... Switch 15 ... Double pipe type Heat exchanger E: Waste inlet F: Waste outlet

Claims (3)

[Claims] 1. A vacuum tank for storing waste, a steam compressor for compressing steam from the vacuum tank, a steam condenser provided in the vacuum tank and thermally connected to the tank, A non-condensable gas discharging means for spontaneously discharging non-condensable gas of the type, and a condensed water discharging means for spontaneously discharging condensed water from the steam condenser. A superheater of a steam recompression vacuum drying device, characterized by having an intake heating device for heating air. 2. The super heater of a steam recompression vacuum drying apparatus according to claim 1, wherein said suction heating device is an electric heater provided in a suction pipe. 3. The super heater of the steam recompression vacuum drying apparatus according to claim 1, wherein the suction heating device is a heat exchanger that uses steam discharged from the steam compressor provided in the suction pipe as a heat source.