JPS61202043A - Waste heat recovering element - Google Patents

Abstract

PURPOSE:To maintain a high fuel cost efficiency of the titled element as a whole by constituting the element in such a manner that a cylindrical flue is provided in a substantially perpendicular direction, a heat exchange part filled with a heat medium around the periphery thereof, and cooled waste gas forming a downward flow flows out toward a lower outlet port together with liquid drops generated in the inside of a heat transfer wall of a flue. CONSTITUTION:A boiler waste heat pipe is coupled and fixed to the flue inner cylinder 2 of a waste heat recovering element, and further the flue inner cylinder is fixed and connected to a discharge port 3 for waste gas and waste liquid. A space encircled by the flue inner cylinder 2 is filled with water as a heat medium 8 and constitutes a heat exchange member 12. A circulating port 9 of a heat exchange coil 7 is connected to a load 10. The waste gas from a boiler introduced from the top portion of the waste heat recovering element is robbed of its sensible heat and latent heat by low- temperature water at the heat exchange portion and is converted into a low- temperature waste gas. The low-temperature waste gas flows downward and simultaneously is robbed of its latent heat. Acidic water contents condensed on the inner wall surface of the flue inner cylinder flow down and are discharged out of the waste gas and waste liquid discharge port 3.

Description

[Detailed Description of the Invention] Industrial Fields of Use The present invention is applicable to heating in residential, industrial, commercial, etc.
This relates to a waste heat recovery element from a boiler used for hot water supply.

Conventional technology Recently, for applications where the heating load fluctuates frequently, methods have changed from installing a single large boiler that can handle the maximum load to arranging groups of many small boilers and operating the necessary boilers sequentially according to the load. is becoming more advantageous in terms of energy conservation.

In any of the above cases, conventional technology improves the performance of each boiler and maintains high performance during overall operation. Therefore, in order to improve fuel consumption efficiency, the exhaust gas temperature of each boiler must be kept as low as possible. Various efforts have been made for each individual boiler to lower the temperature, which inevitably makes the whole boiler more expensive.

Problems to be Solved by the Invention As described above, in order to improve the boiler p combustion efficiency, there is a need to lower the temperature of the combustion exhaust gas discharged from the boiler as much as possible. However, the temperature of the boiler exhaust gas is set at 250° to avoid the risk that the acid groups in the exhaust gas will be cooled below the acid dew point and turn into acidic droplets that will corrode the heat transfer surface of the heat exchanger.
Normally, it is maintained at about C or higher. If this exhaust gas temperature can be lowered to the water vapor dew point temperature range or lower, combustion efficiency can be expected to improve by about 10 degrees. The heat transfer part of the heat exchange part of the boiler needs to be made of an expensive corrosion-resistant material, making it expensive. In some cases, the temperature of the exhaust gas from the boiler remains normal and a heat exchange device is installed to recover waste heat during the upward flow of the flue, but even in that case, if the exhaust gas temperature is lowered as described above, Not only is there a risk of malfunction due to the backflow of acidic condensed water into the boiler, but the overall cost is unavoidable. It was designed to maintain the

Means and operation for solving the problems The waste heat recovery element according to the present invention is an element that constitutes a part of an energy-saving boiler system, and is a fuel that is used in combination with a boiler as an element consisting of a single unit or a plurality of units. It is an element for waste heat recovery aimed at improving consumption efficiency, and has one or more cylindrical flues in a nearly vertical direction so that the exhaust gas from the boiler flows downward. A heat exchange part filled with a heat medium, preferably water, is placed on the outer periphery, and the exhaust gas cooled by the heat medium flows downward, and droplets are generated inside the heat transfer wall of the cylindrical flue. While combining the action of helping the boiler exhaust gas flow to the lower outlet within a short time due to gravity, the temperature of the exhaust gas is lowered to a level where not only the sensible heat in the boiler exhaust gas but also the latent heat of water vapor can be sufficiently recovered and released to the outside. This is a waste heat recovery element that makes it possible to improve fuel consumption efficiency.

That is, the combustion gas discharged from the individual boilers is kept at a temperature that can avoid condensation of acid groups contained in the gas, preferably at 250 degrees.
The latent heat in the combustion gas is also recovered by collecting it in the waste heat recovery element and releasing it to the outside as low-temperature combustion exhaust gas and waste liquid. This is made possible in the waste heat recovery element according to the invention because the exhaust gas flow and the condensed droplets form the same downward flow, preventing the droplets from flowing back into the boiler.

Embodiment The waste heat recovery element shown in FIG. 1 is an embodiment used for an energy-saving boiler system consisting of two boiler elements 11 connected to a load 13 as shown in FIG. The exhaust gas pipe 4 is composed of two pipes. The boiler exhaust gas pipe 4 is connected and fixed to an inner flue tube 2 that protrudes from the top of the outer can l of the waste heat recovery element, and the flue inner tube further protrudes from the bottom of the outer can to form an exhaust gas and liquid discharge port 3. It is fixedly connected to. The space surrounded by the flue inner cylinder 2 and the outer can body 1 is filled with water as a heat medium 8, and the heat exchange part 1
A circulation port 9 of a heat exchange coil 7 is connected to a load 10.

The exhaust gas from the boiler introduced from the top of the waste heat recovery element has its sensible heat and latent heat stolen by low-temperature water in the heat exchange section, becomes low-temperature exhaust gas, and flows downward. Acidic moisture condensed on the wall surface also flows downward and is discharged to the outside from the exhaust gas/liquid drain port 3 provided at the bottom of the waste heat recovery element. In this embodiment, the flue inner cylinder has a single structure that can be easily replaced, but it is also possible to have a plurality of flue inner cylinders.

Effects of the Invention In an energy-saving boiler system consisting of a single or multiple boiler configurations, the waste heat recovery element based on the present invention can be used in combination with a boiler as an element for the purpose of intensive recovery of waste heat in exhaust gas. Since the fuel consumption efficiency can be improved even if the exhaust gas from the boiler maintains a suitable high temperature, there is no need to provide means for improving efficiency for each individual boiler, making each boiler simple and inexpensive. This eliminates boiler troubles caused by acidic condensed water as a result of recovering latent heat from exhaust gas, and the entire group system can achieve a simple, inexpensive, and energy-saving boiler system with high reliability and good fuel consumption efficiency.

Furthermore, as an incidental effect, water as a heat medium heated by waste heat recovery can be used as hot water for hot water supply, or as a heat source for cogeneration by using the heat exchange coil 7 provided in the heat medium. There is also.

[Brief explanation of the drawing]

Fig. 1 shows a waste heat recovery element according to an embodiment of the present invention;
The figure shows an example of an energy-saving system in which the present invention is combined with two boiler elements. , 5 is a water supply port, 6 is a hot water supply port, 7
12 is a heat exchange coil, and 12 is a heat exchange section. Patent applicant: Toyo Machinery Co., Ltd. Figure 1

Claims (6)

[Claims] (1) Inside the outer can forming a rigid container, one or more flue inner cylinders are installed almost vertically, penetrating the top and bottom of the outer can, and the upper end of the flue inner cylinder is connected to the boiler. Connected to the exhaust gas pipe terminal, the lower end is connected and fixed to the exhaust gas/exhaust liquid discharge port, and the inside of the rigid container consisting of the outer can body and the flue inner cylinder is filled with a heat medium to form a heat exchange section. death,
By cooling the exhaust gas from the boiler in the heat exchange section, the exhaust gas is caused to flow downward, and the latent heat of the steam contained in the exhaust gas is stolen and the moisture that condenses on the inner surface of the flue cylinder is removed by gravity. A waste heat recovery element that is used in combination with a boiler that discharges gas from a discharge port provided at the bottom of the outer can body in the same direction as the exhaust gas flow. (2) The waste heat recovery element according to claim (1), wherein the upper end of the inner flue tube passes through the top side surface of the outer can body. (3) The waste heat recovery element according to claims (1) and (2), wherein the lower end of the flue inner cylinder penetrates the bottom side surface of the outer can body. (4) The waste heat recovery element according to claims (1), (2), and (3), wherein the outer can forming the rigid container has a rectangular shape. (5) Claims (1) (2) in which the flue inner cylinder is rectangular
) (3) The waste heat recovery element described in (4). (6) Claim (1) in which the heat in the waste heat recovery element can be taken out by installing a heat exchange coil in the heat medium or by providing a circulation port to take out the heat medium to the outside.
(2) The waste heat recovery element described in (3), (4), and (5).