JPS6115003A - Recovery device for waste-heat energy - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a waste heat energy recovery device capable of recovering thermal energy from waste heat gases of different concentrations discharged from a plurality of plants. be.

[Prior Art] Currently, in order to promote energy conservation, attempts are being made to recover waste heat energy from various plants. However, waste heat energy is not utilized in plants that require a heat source with a fixed amount of heat and a predetermined concentration, such as a distillation type seawater desalination plant.

This is because the amount of waste heat varies depending on the load condition of the plant, and even the lowest amount of waste heat must satisfy the amount of heat required by a seawater desalination plant, which limits the scale and type of plants. This is because chemical plants installed in parallel with desalination plants often do not have the amount of waste heat required by seawater desalination plants.

Therefore, at present, power generation plants and the like are installed in parallel to produce waste heat (steam) sufficient to operate seawater desalination plants. For this reason, when installing a seawater desalination plant, it is inevitable that the equipment will be extremely large-scale, considering its heat source. Furthermore, in order to obtain the required amount of heat even when the load on the power plant is low, there is also the uneconomical aspect that the operating rate of the power plant cannot be lowered below the required level.

[Problems to be Solved by the Invention] In view of the above-mentioned circumstances, the present invention makes it possible to effectively utilize the waste heat discharged from multiple plants, and enables waste heat recovery to be carried out even in plants where waste heat recovery was conventionally difficult for a single plant. It was designed so that it could be done.

[Means for Solving the Problems] The present invention provides that the waste heat gas of at least the lowest hot water temperature among the waste heat gases from a plurality of plants is directly led to a heat exchanger to exchange heat with a fluid to be heated, and also to exchange heat with a fluid to be heated. The present invention is characterized in that at least one of the hot gases is guided to a required heat exchange device, and the heated fluid obtained by the heat exchange device is guided to the heat exchanger to exchange heat with the fluid to be heated.

[Example] The present invention will be described in detail below with reference to the drawings.

First, a first embodiment will be explained with reference to FIG.

This example shows an example in which the present invention is implemented in a seawater desalination plant, and 1 is an evaporator of the plant;
The seawater 2 discharged from the evaporator 2 is heated by the recovery device of the present invention and returned to the evaporator 1 again.

The seawater 2 is divided into two streams, one of which is sent to a heat exchanger 3 and the other one of which is sent to a heat exchanger 4. At the outlet of each heat exchanger 3.4, there is a concentration detector 5゜6 and a flow rate adjustment valve 7, 8, respectively.
is installed, the outlet concentration of seawater is detected, and the flow rate is 1g1u - 2! with valves 7 and 8 so that this concentration becomes a predetermined value. It controls agriculture.

The exhaust gas 9 having a relatively low concentration is introduced into the heat exchanger 3, and heat exchange is performed between the exhaust gas 9 and the seawater 2 to heat the seawater 2 to a required concentration. The reduced concentration of exhaust gas continues into the chimney 1.
0 and is emitted into the atmosphere.

In addition, the exhaust gas 11 with a relatively high concentration is led to the waste heat boiler 12, where steam is once generated, and the steam converts seawater 2.
Let it heat up. That is, the high-temperature exhaust gas 11 is discharged from the chimney 10 after generating steam in the waste heat boiler 12 and reducing the concentration to a required level. Steam 13 from waste heat boiler 12
is guided to the heat exchanger 4, heats the seawater 2, and then condenses. Further, 14 is a dump condenser which condenses excess steam. Water condensed in the heat exchanger 4 and dump condenser 14 is circulated by a condensate pump 15. The steam line 16 to the heat exchanger 4 and the steam line 17 to the dump condenser 14 are each provided with flow control valves 18 and 19, and based on the detection results of the pressure detector 20 provided in the heat exchanger 4, The flow rate adjustment valves 18 and 19 adjust the flow in each line, and even if there are load fluctuations on the high-temperature exhaust gas side and fluctuations in the amount of steam generated, the amount of steam supplied to the heat exchanger 4 is always maintained at a predetermined value. make it happen.

Here, the reason for not directly exchanging heat between the exhaust gas on the high temperature side and the seawater is that if the seawater is heated with a high-temperature heat source, the molten components in the seawater will adhere as scale to the heat transfer surface of the heat exchanger, reducing heat transfer efficiency and cleaning. This is because there are many problems such as the need for heat exchangers, and for the same reason, the seawater concentration at the outlet of each heat exchanger 3 and 4 is controlled.

In the above configuration, there are two heat recovery sources, which supplement each other's heat quantity, and even if one heat source experiences load fluctuations and does not have the capacity to handle the load fluctuations alone, it can be handled by the other heat source. .

Further, even if the concentration of exhaust gas is different, waste heat can be recovered without any problem.

FIG. 2 shows another embodiment of the present invention, in which the exhaust gas 11 on the high temperature side is passed through an intermediate heat exchanger 21 to be reduced to a required concentration. The exhaust gas concentration is detected by a concentration detector 22, and the flow rate of the cooling water is adjusted by a flow rate adjustment valve 23 so that the exhaust gas concentration becomes a required value.

In the one shown in FIG. 2, the heat exchanger 4 exchanges heat between the exhaust gas and seawater, so it may be integrated with the heat exchanger 3.

FIG. 3 shows yet another embodiment, in which heat exchangers 3 and 4 are provided in tandem to heat seawater in two stages.

Note that the exhaust heat source is not limited to exhaust gas, and may be any hot gas, ie, waste heat gas, obtained from a cement plant or the like. 3 more
The heat recovery of the above plant may be performed.

[Effects of the Invention] As described above, the waste heat energy of two or more plants can be recovered at the same time, and energy saving can be further promoted.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of another embodiment of the same, and FIG. 3 is an explanatory diagram of still another embodiment. 2 is seawater, 3 and 4 are heat exchangers, 9 and 11 are exhaust gases, 12
21 indicates a waste heat boiler, and 21 indicates an intermediate heat exchanger. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) Directly guide at least the lowest concentration of waste heat gas from a plurality of plants to a heat exchanger to exchange heat with the fluid to be heated, and at least one of the other waste heat gases to a required heat exchange device. A waste heat energy recovery device characterized in that the heated fluid obtained by the heat exchange device is guided to a heat exchanger to exchange heat with the heated fluid.