JPS605280Y2 - Combustion waste gas heat recovery equipment - Google Patents

Description

[Detailed description of the invention] This invention relates to a heat recovery device for combustion waste gas in boilers, incinerators, other combustion devices, or drying devices such as kilns.
The purpose is to prevent corrosion of heat exchangers.

Heat recovery devices for waste gas (combustion gas) discharged from combustion devices such as boilers and incinerators or drying devices such as kilns are already known, but generally a heat exchanger is installed in the flue and the A room temperature liquid such as water is supplied as a medium.

Therefore, if the temperature difference between the heat exchanger and the waste gas causes dew condensation on the outer periphery of the heat exchanger, and if the waste gas contains sulfur, acid corrosion will occur on the heat exchanger. .

For this reason, conventionally, heat exchangers made of acid-resistant materials were expensive, and in order to prevent acid corrosion, heat exchangers were
The drawback is that heat can only be recovered up to a temperature 60°C higher.

Furthermore, since the temperature of the fluid on the low temperature side is also low, it is currently necessary to reheat it using steam or other heat sources before exchanging heat, which has the disadvantage of poor thermal efficiency.

The present invention is intended to solve the above-mentioned problems in the heat recovery of waste gas containing heat.

To explain this with reference to the embodiment shown in the drawings, 1 is a boiler, incinerator, kiln, or other combustion or drying device, and gas containing sulfur is led from a flue 2 to a chimney 3 and released into the atmosphere. It has become.

4 is a heat exchanger placed at an appropriate location in the flue 2, which recovers heat from the waste gas.

5 is a fan installed in the flue 2 at the front stage of the heat exchanger 3, which sends the waste gas to the heat exchanger 3, but if there is room for a forced fan such as in a boiler, fan 2 can be omitted. It is.

Reference numeral 6 designates a second heat exchanger, which is connected to the first heat exchanger 4 through piping 7 and 8, and transfers a heat medium heated to about the acid dew point temperature between the heat exchangers 4 and 6. It is designed to circulate.

Reference numeral 9 denotes a pump interposed in the pipe 7, which circulates the heat medium.

Reference numeral 10 denotes an expansion tank connected to the pipe 7, which absorbs thermal expansion due to temperature rise of the heat medium at the start of operation, and
This applies suction pressure to the pump 9.

Reference numeral 11 indicates a temperature control device installed in the piping 7 to detect the temperature of the heat medium that has completed heat exchange in the heat exchanger 6, and adjusts the regulating valve described later. Reference numeral 12 indicates a heat recovery device connected to the heat exchanger 6. With piping,
This allows water or other liquids to be fed into and removed from the heat exchanger 6 for heat exchange with the heat medium circulating through the heat exchanger 4.6.

13 is a pump interposed in the piping 12, and 14 is a regulating valve interposed in the piping 12, the opening degree of which is adjusted by a signal from the temperature control device 11 to adjust the amount of ice etc. to be supplied to the heat exchanger 6. The temperature of the circulating heat medium in the pipe 7 is always maintained at about the acid dew point temperature.

Reference numeral 15 denotes a tank body for water and other liquids placed before the pump 13, which is supplied to the heat exchanger 6, and the water and other liquids discharged from it are supplied to the boiler or stored in a tank. be used as appropriate.

The heat medium circulating through the pipes 7 and 8 is heated to about the acid dew point temperature, which is 100°C or higher, so it is suitable to use a liquid mainly composed of organic compounds, and when using water, the boiling point should be It is suitable to provide a pressurizing device for raising the temperature.

The heat medium in the pipes 7 and 8 is heated to about the acid dew point temperature, but is at a low temperature at the start of operation.

Even if this heating is performed using the heat exchanger 4, a heating device (not shown) is provided at an appropriate location in the pipes 7 and 8, and the heat medium is heated until the temperature of the heat medium rises to about the acid dew point temperature. It is also possible to provide heating in the exchanger 4.

The device of the present invention has the above-mentioned configuration, and when the heat medium circulated through the pipes 7.8 enters the heat exchanger 4, it exchanges heat with the waste gas whose temperature is higher than that of the heat medium. None, it becomes high temperature and comes out of the heat exchanger 4.

The heated heat medium enters the second heat exchanger 6, where it undergoes heat exchange again with water or other low-temperature liquid supplied through the piping 12, and the water, etc. supplied through the piping 12 is becomes high temperature.

The heat can be utilized by using the high-temperature water as appropriate.

The device of the present invention recovers the heat of the waste gas as described above, but the heat medium supplied to the heat exchanger 4 installed in the flue 2 through which the waste gas containing sulfur passes is Since it is circulated between the heat exchanger 6 and the pipes 7 and 8,
There is no increase in running costs and it can be operated economically.

Since the circulating heat medium is heated to a temperature approximately equal to the acid dew point temperature, dew condensation does not occur on the outer peripheral surface of the pipe of the heat exchanger 4, and the problem of acid corrosion can be solved. This eliminates the need for the material to be made of acid-resistant and expensive material, which can contribute to cost reduction.

As a result of solving the problem of condensation, it is now possible to lower the temperature of the waste gas in the heat exchanger 4 to near the acid fog temperature.
Heat recovery efficiency can be improved.

Since the heat recovery efficiency in the heat exchanger 4 is high and the circulating heat medium passing through it has a higher temperature, water and other liquids supplied to the heat exchanger 6 through the piping 12 can also be heated to a higher temperature.
It can also increase its utility value.

[Brief explanation of the drawing]

The drawing is a block diagram of an embodiment of the present invention. 2... Flue, 4, 6... Heat exchanger, 7
．． Death: Piping, 11: Temperature control device
12...Piping, 14...Adjustment valve.

Claims (1)

[Claims for Utility Model Registration] 1. A heat exchanger having a first heat exchanger installed in a flue for flue gas containing sulfur, and a second heat exchanger installed outside the flue, The first and second heat exchangers are connected in an annular manner by piping, so that the heat medium passing through them circulates, and the second heat exchanger has a connection with the circulating heat medium. There is piping for supplying water or other liquid for heat exchange between the first and second heat exchangers, and a regulating valve is interposed in the piping, and a pump and a second heat exchanger are installed in the piping connecting the first and second heat exchangers. a temperature control device that detects the temperature of the heat medium exiting the second heat exchanger and adjusts the opening degree of the regulating valve; A heat recovery device for the combustion waste gas sent to the vessel. 2. Combustion waste according to claim 1 of claim 1, in which the piping connecting the first and second heat exchangers is provided with a heating device for heating the heat medium passing through it to about the acid dew point temperature. Gas heat recovery equipment.