JPS5934959B2 - Heat recovery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, in electric furnaces, converters, etc., high temperature exhaust gas of nearly 1000°C is disposed of.

Generally, an exhaust gas boiler is often provided for such high-temperature exhaust gas from the viewpoint of energy saving.

However, in the case of these furnaces, because the amount of dust contained in the exhaust gas is extremely large and the furnace operation is intermittent, exhaust heat is rarely recovered and indirect cooling using cooling towers is used. The temperature of the exhaust gas is lowered by direct cooling, such as by direct spraying with water, and then sent to the dust collector.

The present invention was proposed in view of these circumstances, and involves introducing high-temperature exhaust gas that is intermittently generated and has a high dust content into a water pool in a hot water storage type gas cooler that is open to the atmosphere. and boiling the water in the water reservoir, flowing a heat absorption medium through a heat transfer tube disposed in the water reservoir of the cooler, and recovering the heat of the exhaust gas through the medium. The purpose of this heat recovery method is to develop a new and useful heat recovery method that effectively and stably recovers clean thermal energy using a simple recovery device without adversely affecting the operation of the furnace. It is in the point of providing.

The present invention will be described below with reference to the illustrated embodiments.

In FIG. 1, reference numeral 1 denotes a hot water storage type cooler, through which a duct 2 for high-temperature exhaust gas from a furnace passes through the lower part of the cooler 1, and the exhaust gas is cooled to a predetermined temperature at the outlet of the duct 2.

The duct 2 is formed to have a large diameter so that even if dust is accumulated due to the exhaust gas containing a large amount of dust, it can be easily cleaned.

The cooler 1 has a large capacity and is open to the atmosphere, and a coiled or grouped heat transfer tube 3 through which a heat absorbing medium passes is disposed above a water reservoir 1a containing water.

The water in the cooler 1 is replenished by opening a water supply valve 5 using a liquid level controller 4 as necessary.

The heat transfer circuit 6 connected to the heat transfer tube 3 is configured as a closed circuit, and a heat absorption medium made of water, other gases such as N2 and He, and liquid substances such as Freon and ethylene is circulated by a circulation pump 7. It looks like this.

Note that since the water in the cooler 1 is open to the atmosphere,
Even if the temperature rises and boils due to the exhaust gas passing through the duct 2, the maximum temperature is 100°C, so even if the medium in the circuit 6 is water, it will not boil, but when the circulation of the medium is stopped, etc. Considering safety, it is desirable to apply some pressure.

8 is an N2 cylinder for this pressurization, and 9 is a pressurizer.

Note that such a device is not necessary when a liquid that does not boil at 100° C. is used as the medium.

The heat transfer circuit 6 is provided with a heat transfer section 11 extending into a secondary heat exchanger 10, and a water supply section 12 and a utilization section 13 are connected to the heat exchanger 10.

In the illustrated embodiment, when high-temperature exhaust gas flows into the duct 2 as shown by the arrow, a water reservoir 1 in the cooler 1
The temperature of the water in a rises and begins to boil.

Since the cooler 1 is open to the atmosphere, the maximum
The temperature rises to 0°C.

Therefore, the heat absorption medium circulating in the heat transfer tubes 3 by the circulation pump 7 is heated by the boiling water in the cooler 1, and is sent to the heat transfer section 11 in the secondary heat exchanger 10, where the heat absorption medium is Heat is exchanged with the cold water supplied to the exchanger 10.

Therefore, when a valve (not shown) of the usage part 13 is opened as necessary, hot water is supplied and cold water is replenished from the water supply pipe 12.

Although media other than water can be used here as well, water is generally the easiest to use.

Note that when the heat recovered by the heat exchanger 10 is used for preheating of some industrial process, the heat exchanger 10
Putting the necessary fluid inside will increase its effectiveness.

In the embodiment shown in FIG. 2, the heat transfer circuit 6 connected to the heat transfer tube 3 is configured as an open circuit, and its inlet portion 14 is connected to a water supply or the like, and the heat transfer circuit 6 is connected to the heat transfer circuit 6. When the valve 15 is opened, hot water is supplied.

In the figure, parts equivalent to those of the above embodiment are given the same reference numerals.

In the embodiment shown in FIGS. 3 and 4, a large-diameter exhaust gas duct 2 is installed at the bottom of a vertical cooler 1 that is open to the atmosphere.
is connected, and the high-temperature exhaust gas fed into the cooler 1 from the same duct 2 rises through the vertical gas passage 16 communicating with the bottom of the cooler 1, and then reaches a predetermined temperature through the exhaust duct 17 communicating with the upper end of the cooler 1. It is cooled down to a temperature and then discharged.

The gas passage 16 is constituted by a large number of smoke pipes 18,
The area surrounded by the outer plate 19 and the group of smoke tubes 18 constitutes a water reservoir portion 1a, and the heat transfer tubes 3 are arranged between the groups of smoke tubes 18 and connected to the heat transfer circuit 6.

Although the circuit 6 is configured as a closed circuit in the illustrated example, it may be an open circuit.

In the figure, parts equivalent to those of the above embodiment are given the same reference numerals.

Note that the heat recovery method according to the embodiment described above is the same as that in the embodiment shown in FIG. 1, so a description thereof will be omitted.

In the case of this embodiment, the cooler 1 is made vertical to prevent dust from accumulating and to effectively recover heat.

As described above, in the present invention, a hot water storage type gas cooler having a water reservoir portion open to the atmosphere is used, and high temperature exhaust gas generated intermittently is introduced into the cooler to create a water reservoir. By boiling the water, the heat of the exhaust gas is indirectly recovered through the heat absorption medium flowing through the heat transfer tube installed in the cooler. This makes it easier to use the heat of the exhaust gas that is generated by averaging it, and as mentioned above, by making the heat recovery of the exhaust gas intermittent, it becomes possible to remove dust from the exhaust gas, and the water pool is removed from the atmosphere. By using a boiling type that is open to water, the temperature of the water pool in the cooler can be stabilized, making a cooling tower for forced cooling unnecessary, and greatly reducing construction costs and ordinary costs.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of one embodiment of a heat recovery device for carrying out the heat recovery method according to the present invention, FIG. 2 is a partial vertical sectional view of another embodiment, and FIG. 3 is a further embodiment of another embodiment. Example longitudinal section, 4th
The figure is a view taken along arrows IV-IV in FIG. 1...Cooler, 1a...Water pool, 2
...Duct, 3...Heat transfer tube, 6...
...Heat transfer circuit, 7...Circulation pump.

Claims (1)

[Claims] 1. Introducing intermittently generated high-temperature exhaust gas with a high dust content into a water pool in a hot water storage type gas cooler open to the atmosphere, boiling the water in the water pool, and cooling the water cooler. A heat recovery method comprising: flowing a heat absorption medium through a heat transfer tube disposed in a water reservoir, and recovering heat from the exhaust gas through the medium.