JPH0368721B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a steam system that can be used for waste liquid treatment steam systems, seawater desalination systems, solvent recovery systems, and various other concentrators, and which uses a centrifugal pump. There is no need to worry about cavitation as with conventional pumps, and since the height between the liquid level and the pump suction position can be lowered, the entire device can be lowered, and the structure is simple and costs can be reduced.It is used in energy-saving technical fields. Ru.

BACKGROUND TECHNOLOGY Vapor recompression type steam apparatuses have been widely used in recent years because they can recover latent heat through evaporation and are extremely energy efficient. However, this is only for large scale plants and is not common for small scale plants.

Figure 4 shows a system diagram of a conventional example in which the evaporator employs a thin film drop type with good heat transfer performance.

In FIG. 4, reference numeral 1 indicates a thin film descending type evaporator, 2 a compressor, 3 and 4 preheaters, 5 a pump, 6 a demister, 7 a heat exchanger, and 8 to 15 piping.

Conventionally, the most common centrifugal type was used for the pump 5, but the disadvantage of this is that unless it is at a sufficient height from the liquid level (approximately 2 m), cavitation occurs due to the closeness to the evaporation pressure, and the pump 5 Corrode. Furthermore, since the liquid to be evaporated is waste liquid, seawater, etc., even if a sufficient height from the liquid level is provided, the pump must be expensive to withstand high-temperature and corrosive liquids.

Problems to be Solved by the Invention The present invention makes it possible to reduce the height between the liquid level and the pump suction position in an evaporator having the structure described above, without causing cavitation unlike a centrifugal pump. The goal is to have a simple configuration, compact size, and low cost production.

Means for Solving the Problems The present invention employs the following means to solve the above-mentioned problems. That is, the circulation pump of the heat exchanger that performs evaporation and condensation is a bubble pump or steam ejector that uses the discharge gas of the vapor recompression compressor as a driving source.

EXAMPLE Next, an example of the present invention will be described in detail with reference to FIG. 1 showing a diagram of the apparatus, FIG. 2 showing details of the bubble pump, and FIG. 3 showing details of the steam ejector.

In FIGS. 1, 2, and 3, the same parts as in FIG. 4 are given the same numbers, and explanations thereof will be omitted.

In Fig. 1, reference numeral 16 is a bubble pump, 17 is a pipe, in Fig. 2, 18 is a liquid pumping pipe, 19 is a steam blowing pipe, and in Fig. 3, 19' is a diffuser pipe, 20
21 indicates a steam jet pipe, and 21 indicates a water pumping pipe.

Liquid for treating waste liquid etc. is supplied through piping 13,
One side exchanges heat with the condensate in the preheater 3 and becomes high temperature. Further, the other liquid supplied from the pipe 13 exchanges heat with the concentrated waste liquid in the preheater 4, and becomes high temperature.

The liquid to be treated leaving the preheaters 3 and 4 joins the pipe 8 and enters the liquid supply section in the upper part of the evaporator 1. 1st
In the figure, it is merged with piping 8, but bubble pump 1
It may join the piping 9 upstream of the pump 6, and at that time, depending on the flow rate ratio, a liquid injection pump may be used as a booster.

The liquid that has entered the liquid supply section of the evaporator 1 further enters the heat exchanger 7, where it is heated by the steam from the compressor 2 and evaporates. The liquid and vapor flow down into the liquid-vapor separator, and the liquid collects at the bottom. The stored liquid is either circulated by the bubble pump 16 or sent to the preheater 4 through the piping 10 and taken out as a concentrated liquid.

On the other hand, the vapor separated at the bottom of the evaporator 1 has its mist removed by a demister 6, and is compressed by a compressor 2 to become high-temperature, high-pressure vapor. The high temperature and high pressure steam heats the liquid to be treated in the heat exchanger 7 and condenses it. The condensed liquid passes through the pipe 11, radiates heat in the preheater 3, and is discharged.

On the condensing side of the heat exchanger 7, there is a pipe 12 for discharging non-condensable gas, and if necessary, it is connected to a vent condenser and a vacuum pump (not shown). The driving gas for the bubble pump 16 is the discharge gas of the compressor 2, and is sent through a pipe 17.

As shown in FIG. 2, the piping 17 is connected to the bubble pump 16
The discharged gas exits as bubbles from a large number of holes into the liquid in the liquid pumping pipe 18 which is connected to the steam blowing pipe 19 and connected to the piping 9. This method takes advantage of the fact that the air bubbles and liquid are mixed, which lowers the specific gravity and generates lift. Depending on the pressure of the discharged gas, a steam ejector may be more efficient than the bubble pump 16.

The steam ejector, as shown in FIG.
becomes a negative pressure, and the liquid is sucked into the diffuser tube 1.
9' to convert the velocity head into a pressure head.

Effects of the Invention The configuration described above has the following effects.

(a) Unlike centrifugal pumps, there is no need to worry about cavitation, so the height between the liquid level and the pump suction position can be lowered, allowing the entire device to be lower.

(b) This pump has a simple structure and can be produced at low cost.

(c) Since the discharge gas of the compressor is used as the driving source, a slight increase in the capacity of the compressor is sufficient.
It's a simple system.

(d) Since the discharge gas of the compressor is used as the driving source, the circulating fluid can be heated and the fluid supplied to the heat exchanger 7 can be brought from a supercooled state to a saturated state.

[Brief explanation of drawings]

Figure 1 is a system diagram of the evaporator of the present invention, Figure 2 is a sectional view showing details of the bubble pump, Figure 3 is a sectional view showing details of the steam ejector, and Figure 4 is a system diagram of a conventional evaporator. It is. 1... Evaporator, 2... Compressor, 3, 4... Preheater, 6... Demister, 7... Heat exchanger, 8, 9,
10, 11, 12, 13, 14, 15, 17...
Piping, 16... Bubble pump, 18... Lifting pipe, 1
9...Steam blowout pipe, 19'...Diffuser,
20... Steam jet pipe, 21... Lifting pipe.

Claims (1)

[Claims] 1. In a steam recompression type steam device that uses generated steam as a heating source by pressurizing it, the circulation pump of the heat exchanger that performs evaporation and condensation is replaced by a bubble pump or a bubble pump that uses the discharge gas of the vapor recompression compressor as the driving source. Vapor recompression type evaporator with vapor ejector.