JP2989891B2 - Improved heat exchanger - Google Patents

Description

The present invention relates to heat exchangers, and more particularly to treating particulate materials for the purpose of calcination, drying, reactivation, endothermic and exothermic reactions, and similar heat treatments. Heat exchanger.

In one aspect, the invention provides a heat exchanger for a flowable particulate material, the heat exchanger comprising a heating chamber, heating means provided in connection with the heating chamber, and A container provided above the heating chamber, a discharge chamber provided below the heating chamber, and a set of flow passages extending through the heating chamber and extending between the hopper and the discharge chamber. The discharge chamber has an outlet in a lower part thereof, and the discharge chamber has at least one opening to the heating chamber for releasing gas pressure generated in the discharge chamber.
There are two throttle passages.

According to a preferred feature of the present invention, the flow passage is configured to increase an opening between the discharge chamber and the heating chamber with an increase in temperature.

According to a preferred feature of the invention, the discharge chamber and the heating chamber are separated by a wall, and the flow passage is formed by a hole passing through the wall.

According to a preferred feature of the above feature, the hole is substantially centrally located.

According to a preferred feature of the above two features, the hole is provided with a plurality of kerfs extending radially from the hole.

The present invention will be more fully understood from reading the following description of certain embodiments. The following description is made with reference to the accompanying drawings, in which FIG. 1 is an elevational view, partially in section, of the heat exchanger of the present embodiment, and FIG. FIG. 3b is a schematic plan view of a wall of the heat exchanger separated from the discharge chamber, and FIGS. A schematic elevation view,
The state of the wall part including the passage in various stages of deformation is shown.

This embodiment relates to a heat exchanger for heating such particulate material to dry and / or reactivate the particulate material. The general form of heat exchanger to which this embodiment relates is the subject of Australian Patent No. 574012.

In the past, the heat exchangers described above were used to dry such carbon pulp for the purpose of drying and / or reactivating carbon pulp with organic contaminants so that particulate material passed through the heat exchanger. It has been found that as a result of the thermal decomposition of such organic contaminants in the process, a significantly higher back pressure is created in the discharge chamber. The purpose of the present invention is
The purpose is to provide a means for relieving such gas pressure and removing the harmful gas so as to reduce the possibility of escaping into the atmosphere.

The heat exchanger of the present embodiment includes a substantially cylindrical closed heating chamber 11 for accommodating a nozzle of a burner (not shown), and the nozzle is located at a lower portion of the heating chamber.
It is suspended from 13 and extends almost tangentially into the heating chamber. The side wall of the heat exchanger is covered with a heat insulating material 12. A flue tube 15 is provided at the upper end of the heating chamber for discharging combustion products. At the upper end of the heating chamber 11,
A container comprising a hopper 14 is provided, while a discharge chamber 17 is provided at the lower end of the heating chamber.

The hopper 14 is supported so as to be located above the upper side wall of the heating chamber, so that a space exists between the hopper and the heating chamber. The hopper itself is provided with a plurality of air circulation tubes 20, which extend upwardly from the lower wall to above the expected level of material in the hopper. During use, a heated air flow is generated in an air circulation tube extending from the space above the heat exchanger, and this air flow serves to heat the contents of the hopper and preheat the contents. And / or promotes drying to some extent.

The heat exchanger is provided with a plurality of heat exchange tubes 16 extending between the discharge chamber 17 of the hopper 14 and these heat exchange tubes penetrate the heating chamber. The heating tube is
Any suitable arrangement, such as a plurality of concentric arrangements (only one row is shown), a set of radial arrangements, a random arrangement, or other conceivable forms can be used. The heat exchange tube of this embodiment is suspended from the hopper, and penetrates through holes provided in the upper and lower walls of the heating chamber without being firmly fixed to the heating chamber. Instead, the heating tube can be supported by a discharge chamber. The heat exchange tube 16 is mounted so as to allow for thermal expansion and contraction during the operation of the heat exchanger and a difference in the amount of movement between the heating chamber 11, the hopper 14 and the discharge chamber 17 thereafter. Will be

The discharge chamber is located below the heating chamber and is provided with an outlet 18 shown schematically in the drawing. The discharge chamber cools the material flowing from the heating tube and provides a means to thermally insulate such material from the atmosphere, which is required if the heated material is reactive.

In the case of this embodiment, the discharge chamber 17 and the heating chamber 11 are separated by a wall 21, and a plan view of the wall of the discharge chamber 17 is shown in FIG. Around the wall 21, there are provided a plurality of circumferentially spaced holes 22 for engaging with bolts provided on the lower surface of the heating chamber 11. The wall also has a set of holes 23 radially inwardly spaced from the set of holes 22 such that the holes 23 provide a tight fit for the lower end of the heat exchange tube 16. It is dimensioned (only some of the holes 23 are shown in FIG. 2). The hole 23 is dimensioned so that it does not interference fit with the heat exchange tube, thereby allowing relative movement between the hole 23 and the heat exchange tube due to thermal expansion and contraction. If necessary, a suitable seal can be provided between each hole and the heat exchange tube.

In use, the material is deposited in the hopper 14 and the material flows through the heat exchange tube 16 into the discharge chamber 17. The material is heated in the passage between the hopper 14 and the discharge chamber.
The function of heating is to re-activate in the case of carbon pulp, and to perform any calcination or reaction to dry or remove contaminants or to heat the material. It is. When the heated material enters the discharge chamber, gas is generated from the heated material, which creates a gas pressure in the discharge chamber,
This gas pressure can impede the flow of material into and out of the discharge chamber.

The wall 21 further dividing the heating chamber and the discharge chamber is formed with at least one hole 24 which can be provided at the center as required. A series of radially extending kerfs 25 are provided which are cut around the hole through the wall and have approximately the same length. In addition to or instead of the kerfs, a set of radially extending kerfs 25 can be formed in at least some of the holes 23 containing the heat exchange tubes,
In this case, no seal is provided between the hole tube.

When the heat exchanger is in the start-up phase when the wall 19 is in a substantially cold state, at least the passages defined by the holes 24 and / or the space between the heat exchange tubes, the holes 23 and the respective kerfs 25 are formed. The intervening flow path is substantially closed. However, as the wall is heated, the wall expands, and as a result of this expansion, the wall deforms with its central portion displaced axially. As a result, the portion defined between the kerfs 25 is offset from the plane of the wall, thereby increasing the size of the holes 22 and / or 23. This deformation increases the degree of flow between the discharge chamber and the heating chamber.

When the particulate material supplied to the heat exchange tube is contaminated with an organic substance, a gas product generated by the thermal decomposition of the organic substance generates pressure, whereby the gas product is released from the pores 24. And / or pushed into the heat exchanger via the space between the hole 23 and the heating tube, at which point the gaseous product is consumed in the heating chamber.

If the particulate material is heavily contaminated with organic matter, the flow of gaseous pyrolysis products from the particulate material will be higher, and as a result, combustion occurring in the region of the holes 24 in the heating chamber will be impeded. Section is further heated, thereby providing a kerf 25
The portion defined between them further deviates, which causes the holes 22 to open further, releasing the pressure that would build up in the combustion chamber. The gas flow from the discharge chamber to the heating chamber further ensures that the hot particulate material flowing into the discharge chamber is substantially isolated from the effects of oxidation of the heating chamber.

The heat exchanger of the above embodiment may be particularly effective when it is necessary to re-activate the fine carbon that may be contaminated by a significant amount of organic material in use. It is known.

It should be understood that the scope of the present invention need not be limited to the particular scope of the embodiments described above.

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Claims (7)

(57) [Claims] 1. A heat exchanger for heating a flowable particulate material, comprising: a heating chamber; heating means provided in connection with the heating chamber; and a container provided above the heating chamber. A discharge chamber provided below the heating chamber; and 1 that penetrates the heating chamber between the container and the discharge chamber.
A set of flow passages, wherein the discharge chamber has an outlet in a lower portion thereof, and wherein the discharge chamber has a heating chamber for releasing gas pressure generated in the discharge chamber. At least one restricted passage that is open to the at least one, and the at least one restricted passage increases an opening degree between the discharge chamber and the heating chamber with an increase in temperature. Heat exchanger characterized by the ability to: 2. The heat exchanger according to claim 1, wherein the discharge chamber and the heating chamber are separated by a wall, and each of the at least one restricted passage is
A heat exchanger comprising a hole penetrating the wall. 3. The heat exchanger according to claim 2, wherein the hole is located substantially at the center. 4. The heat exchanger according to claim 3, wherein the hole is provided with a plurality of kerfs extending radially from the hole. 5. The heat exchanger according to claim 1, wherein the set of flow passages further includes a tube extending from the container to the discharge chamber, and the wall portion includes a set of tubes. The heat exchanger having holes, wherein each of the set of holes accommodates one of the tubes of the set of flow passages. 6. The heat exchanger according to claim 5, wherein at least one of said tubes is received in a non-interference relationship within a corresponding bore, and said at least one restricted passage is A heat exchanger having a void between the at least one tube and an opposing hole. 7. The heat exchanger according to claim 6, wherein a plurality of cut grooves extending in a radial direction from the corresponding hole are formed in the corresponding hole.