JPS59183297A - Heat exchanger of multitubular type - Google Patents

Abstract

PURPOSE:To prevent lowering of heat transfer coefficient in the titled heat exchanger caused by pollution on the heat transfer surfaces or by powdery dust remaining and accumulating on the heat transfer surfaces, by gradually feeding gas being accompanied with powdery dust into a bundle of tubes which are held by tube plates, and by flowing it down at high velocity through heat transfer tubes from the bundle of tubes piercing through a funnel and from the center hole of a funnel. CONSTITUTION:The heat transfer surface of a heat exchanger is composed of a center tube 7 piercing through the center parts of an upper tube plate 5 and a lower tube plate 6 and a plurality of peripheral tubes 8 arranged around the center tube 7. A funnel housing chamber 4 connects a main body 1 to a top cover 2, and gas being accompanied with powdery dust is led into a space enclosed by the tube cover 2 and the funnel 9, passing through said bundle of tubes from the upper end of a bundle of short tubes 19 which pierce through the slant of a funnel, flowing into the peripheral bundle of tubes which are connected to the bundle of short tubes 10, flowing down through the tubes usually at the speed of more than 10 meters per second, flowing into the lower space of a lower tube plate 6 being accompanied with powdery dust, preventing the powdery dust from adhering and accumulating on the inside walls of the tubes. A flow rate controlling valve 13 is fitted to the lower end of a center tube 7, and the flow rate of gas in the center tube is controlled by controlling the sectional area of a flow path in the tube by moving up and down the valve 13, so that the flowing speed of gas flowing down through the peripheral tubes 8 can be controlled within the specified range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention prevents contamination of heat transfer surfaces by such dust or accumulation of dust on heat transfer surfaces when gas accompanied by soot or unburned dust is involved in heat exchange. The present invention relates to a shell-and-tube heat exchanger that can prevent a decrease in heat transfer coefficient.

Generally, recovering and reusing the heat of high-temperature gas is an elementary means of energy saving, and various proposals have been made regarding this method. However, the target of heat recovery as a high-temperature gas is usually combustion waste gas containing fine soot and unburned dust.These dust particles stay or accumulate on the heat transfer surface of the heat exchanger and transfer heat. It often contaminates the surface and its heat transfer ability deteriorates and is inhibited over time. As a heat recovery heat-receiving fluid, whether gas or liquid, it is relatively rare for dust particles to be entrained in the heat transfer surface like high-temperature waste gas, and it is difficult to prevent the heat transfer coefficient from decreasing. The consideration is much less than the former. Therefore, countermeasures against contamination of heat transfer surfaces should be aimed at high-temperature waste gas accompanied by dust, and the present invention also aims to prevent contamination of heat transfer surfaces due to dust entrained in high-temperature waste gas. It is in.

The vertical multi-tube heat exchanger of the present invention includes a heat exchanger tube consisting of a tube passing through the center of an upper tube sheet and a lower tube sheet, and a plurality of tubes around the tube. The tips of a plurality of tubes penetrating the funnel-shaped slopes attached to the poison collection chamber are respectively inserted, and the tips of the funnels are fitted into the upper end opening of the central heat exchanger tube. This heat exchanger is equipped with a flow rate adjustment mechanism that adjusts the flow rate of gas into the central pipe by raising and lowering a flow rate adjustment valve fitted in the opening.

When a gas entrained with dust is introduced into the space inside the funnel of the upper lid of the heat exchanger 1, the gas flows down from the funnel penetrating tube through the surrounding heat transfer tube at high speed, which prevents dust from adhering to the tube wall, and also prevents dust from accumulating on the funnel slope. The collided dust slides down the funnel slope, flows into the central tube, and flows down the tube, thereby preventing dust from falling and accumulating on the upper tube plate. Furthermore, if the funnel slope effect causes the gas to concentrate too much in the central tube, the flow velocity in the peripheral heat transfer tubes will decrease.1. In order to prevent the heat transfer coefficient from decreasing due to dust adhering to the tube wall, a gas flow rate adjustment mechanism is attached to the lower opening of the central tube to adjust and limit the gas flow rate. In addition, in order to eliminate the accumulation of dust inside the heat exchanger tubes, we have a mechanism that sequentially blows high-speed gas into these heat exchanger tubes and uses the nutz blow effect to forcibly remove the dust that has accumulated inside the tubes. are doing. The mechanism is provided with a tube plate at the top of the funnel that abuts the upper end of the funnel penetrating tube and the center hole of the funnel, or holds and fixes another group of tubes inserted into these respectively. A rotary plate having holes is rotated on a tube plate, a gas having a pressure higher than that of the dust-entrained gas is introduced onto the rotary plate, and this gas is transferred to the tube group held on the tube plate by the rotating operation of the rotary plate. By sequentially flowing down the inside of the heat transfer tube from the funnel penetrating tube group and the center hole of the funnel, the walls of the heat transfer tube are cleaned cyclically or intermittently by the nutsplow action.

Next, one embodiment of the heat exchanger of the present invention will be described with reference to the drawings.

Fig. 1 is a longitudinal sectional view of the vertical multi-tubular heat exchanger of the present invention, Fig.
The figure is an enlarged elevational view of the mechanism that fits into the lower end of the central tube and moves up and down to adjust the cross section of the pipe, Figure 3 is a side view of the same, and Figure 4 is the upper part of the multi-tube heat exchanger of the present invention. FIG. 5 is a partial vertical sectional view showing a state in which a suit blowing mechanism is added, and FIG. 5 is a plan view of FIG. 4 with the top cover removed. In the first, second and third figures, 1 is the heat exchanger body, 2 is the top cover, 3 is the bottom bottom, 4
is the funnel containment chamber. A heat transfer surface is constituted by a central tube 7 passing through the center of the upper tube sheet 5 and the lower tube sheet 6, and a plurality of peripheral tubes 8 arranged around the central tube. The funnel storage chamber 4 is the main body 1
and the upper lid 2, gas accompanied by dust is introduced into the space surrounded by the upper lid 2 and the funnel 9, passes through the upper end of the small tube group 10 that penetrates the slope of the funnel, and passes through the tube group and connects to the surrounding area. It flows into the tube group and flows normally at a speed of 10 m/s or more, preventing dust from adhering to the inner wall of the tube and depositing on the lower tube plate 6.
Flows into the space below, accompanied by dust. A part of the gas that did not flow into the small tube group 10 collides with the slope of the funnel, causing the entrained dust to slide down the slope, gathering at the center hole of the funnel, and flowing down the central pipe 7 connected to Dj together with the dust. Since dust is concentrated in the central pipe, it is desirable to make the diameter of the pipe larger than that of the peripheral pipe 8 to prevent blockage due to dust, but this is not limiting. If gas is allowed to freely pass through the center pipe Z, the amount of gas passing through the peripheral pipe 8 will decrease due to concentration of gas, and the drop in flow velocity will cause dust to easily adhere to the pipe wall, which together with the drop in flow velocity. In order to prevent this from lowering the heat transfer coefficient of the peripheral tube group, a flow rate control valve 13 is fitted to the lower end of the central tube 7, and by moving it up and down, the cross section of the flow path in the tube is adjusted to adjust the gas flow rate in the central tube. The rate of gas flow within the peripheral tube 8 is regulated and maintained. Reference numeral 11 denotes a handle for operating the rotating shaft 12 from the outside of the lower sole 3, and a shaft seal is provided at the portion where the shutter 12 penetrates the lower sole circumferential wall. The rotary shaft 12 has a crank-shaped bend and is connected to the lower end of the control valve 13 by a mating plate 14, and the rotation angle of the control valve 13 is determined by the rotation angle of the rotary shaft 12. The operating mechanism of the control valve 13, which is shown enlarged in FIGS. 2 and 6, is just one example, and an external cam mechanism, hook and pinion mechanism, etc. may also be considered, but the key is to operate from the outside of the heat exchanger. It is sufficient to be able to manipulate the position of the control valve. 15 is an inlet for high-temperature gas entrained with dust, and 16 is an outlet thereof. The dust that flows into the bottom 2 through the heat transfer tube 7.8 falls and accumulates in the lower part of the bottom space, but some of the fine particles enter the outflow port 1 along with the gas.
It may also flow from 6. Reference numeral 17 denotes a filter for removing dust accumulated on the bottom, and the dust is removed intermittently. Reference numeral 18 indicates an inlet for the fluid outside the heat transfer tubes, and 19 indicates an outlet, between which a strainer plate 20 is installed. The raw fluid, gas, and liquid outside the pipe are selected depending on the heat exchange process, but they are usually clean fluids that do not contain dust, and no particular consideration is given to dust. The heat exchanger of the present invention prevents phenomena such as constriction, clogging, solidification, and fixation of the heat transfer tube inlet due to the accumulation and growth of dust on the upper tube sheet in a normal multi-tube heat exchanger, and heat transfer. Since dust contamination on the pipe walls is less likely to occur, stable and steady operation is maintained, and the operability is significantly improved. In order to further ensure the effects of the present invention, it is also conceivable to add a cis-tubular effect by periodically co-flowing or intermittently blowing a gas having a higher pressure than the dust-entrained gas into the heat transfer tube. In FIGS. 4 and 5, a dust entrained gas inflow chamber 21 is connected to the upper end of the funnel storage chamber 4, and a dust gas inlet 15 on which the upper lid 2 is attached is connected to the peripheral wall of the dust gas inflow chamber 21 from the upper lid 2. Relocate. The upper end of 21 is sealed by a fixed plate 22, and the funnel slope penetrating pipe 1 is passed through this.
0, and the connecting tube 24 that reaches the center hole of the funnel are arranged, but the upper ends of the connecting tubes 25 and 24 do not protrude beyond the upper surface of the fixing plate 22, and the surface is kept smooth.

When the connecting pipes 23 and 24 connect to the funnel slope penetrating pipe 10 and the funnel center hole, the tips of the connecting pipes are squeezed so that the connection does not obstruct the flow of dust-entrained gas into the funnel 10 and the funnel center hole. It is necessary to take measures such as enlarging the upper end of the funnel slope penetrating pipe 10 or maintaining a gap between the upper end of 10 and the lower end of 23. A rotary plate 25 is mounted in contact with the upper surface of the fixed plate 22. A partial opening 26 is bored in 25, and its position moves circularly as 25 rotates, and the upper end of the connecting tube 23 is sealed except for the opening, and only the connecting tube opened by the opening rotates. This serves as a passageway for high pressure gas introduced onto the plate 25. The connecting pipe that becomes the gas passage is
As the rotating plate rotates, its position changes periodically.

The connecting pipe 24 in the center is always open, but this is to ensure that the dust flowing into the center hole of the funnel flows down, and since the gas flow rate in the center pipe 7 can be controlled by the flow rate control valve 15, there is no problem. do not have. Reference numeral 27 denotes a rotating shaft for driving the rotating plate, and a shaft seal is applied to the portion that passes through the upper cover. ,2
Reference numeral 8 denotes an electric motor with a speed reduction mechanism attached to the upper lid 2, and its rotation is preferably at a linear speed of several revolutions per minute or less. Reference numeral 29 is an inlet for high pressure gas provided in the upper lid 2, and it may be introduced simultaneously with the dust gas or may be introduced intermittently. High-pressure gas flows into the upper lid space from 15 and flows down at high speed through connecting pipes 25 and 24 that connect to rotary plate openings, and passes through the funnel slope penetrating pipe and the funnel center hole to dust the heat transfer tubes 7 and 8. When mixed with the entrained gas, or when the entrained dust gas is stopped, it flows down inside the heat transfer tube 7.8 preferably at a speed of 20 meters or more per second, exhibiting a suit blowing effect, and purifying the tube wall. Even if there is dust adhesion and accumulation, it is forcibly removed. This makes it possible to keep the heat exchanger tube wall clean even against gases accompanied by highly adhesive dust, thereby further achieving the object of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the vertical multi-tubular heat exchanger of the present invention, Fig.
The figure is an enlarged elevational view of a mechanism that fits into the lower end of the center tube and adjusts the cross section of the pipe by dropping it, FIG. 5 is a side view of the same, and FIG. 4 is a multi-tube heat exchanger of the present invention. FIG. 5 is a plan view of FIG. 4 with the top cover removed. 1 Heat exchanger body 12@J rotating shaft 2 Same as above Upper lid
16 Flow control valve 3 Upper and lower bottoms
14 Plying plate 4 Funnel storage chamber 15 Dust-entrained gas inlet 5 Upper tube plate 16 Upstream outlet 6 Lower tube plate 17 Accumulated dust extraction white 7 Center tube 18 Extra-tube fluid inlet 8 Peripheral tube 19 Extra-tube fluid outlet 9
Funnel 20 Same as above Jama plate 10 Funnel penetration pipe 21 Dust-entrained gas inflow chamber 11
Control valve operation hand/I/ 22 Connecting pipe fixing plate 25 Peripheral connection - W 27 Rotating plate drive shaft 24 Center connecting pipe 728 Low-speed electric motor 25 Rotating plate 29 Blow-off gas inlet 26 Rotating plate opening

Claims (1)

[Claims] (2) A cylindrical heat exchanger main body having an inlet and an outlet for extra-tubular fluid, with open buttons at both ends, an upper tube plate and a lower tube plate attached, and a central tube provided in the center of the heat exchanger body and its surroundings. Heat exchanger tubes consisting of a plurality of tubes arranged in the upper tube sheet and the lower tube sheet are passed through the upper tube sheet and the lower tube sheet, and the tips of the plurality of tubes passing through the funnel-shaped slope attached to the upper part of the upper tube sheet are inserted into the peripheral heat exchange tubes. Insert into the top opening,
And when the tip of the funnel fits into the upper end opening of the center tube,
, a multi-tube heat exchanger in which a flow rate adjustment mechanism for adjusting the opening cross section of the central tube is attached to the lower end opening of the central tube.