JPH0313481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bottom-hole steam generator having a small diameter and compact configuration.

In the case of a bottom-hole boiler, the diameter must be small to match the size of the well, and the length must be as small and compact as possible to facilitate insertion and installation within the well and transportation to the well. is requested.

However, in reality, the evaporative heat transfer surface is disposed within a small diameter, resulting in a large length, and when the combustion exhaust gas is discharged to the ground, the temperature in the exhaust pipe becomes below the dew point, causing a problem of constant temperature corrosion of the pipe. In this case, it is possible to use stainless steel pipes with good corrosion resistance, but it is not economically viable to use expensive stainless steel pipes for long-distance conduits to the ground, and it is also necessary to use suitable coating materials that can withstand normal exhaust temperatures. The reality is that we cannot find anything.

The present invention was made in view of the above-mentioned circumstances, and an object of the present invention is to provide a bottom-hole steam generator that is small and has high heat transfer efficiency.

The bottom-hole steam generator of the present invention has a cylindrical evaporator pipe section formed by interconnecting vertical evaporator pipes connected to a water supply header in the outer wall of a cylindrical main body having a combustion exhaust gas outlet at the top. A gap is provided between the evaporator tube and the outer wall of the main body, and a refractory material is provided inside the upper part of the evaporator tube section to form a combustion chamber, and the lower part thereof is a radiant heat transfer section, and the evaporator tube is separated at the lower end. It forms a combustion exhaust gas passage and is bent inward in the vertical direction to form a convection heat transfer section.

An embodiment of this invention apparatus will be described below with reference to the drawings. In the figure, reference numeral 20 denotes a cylindrical outer wall of the main body, and a combustor 10 is provided at the center of the top, and a combustion exhaust gas outlet (not shown) is provided at the outer periphery of the top. The combustor 10 is configured by providing an atomizer 12, a swirler 13, and a frame holder 14 in a casing 11. An annular water supply header 31 is provided in contact with the combustor 10 and is connected to a water supply pipe (not shown). A large number of evaporation tubes 32 are vertically disposed on the header 31 to form a cylindrical evaporation tube section 30. The evaporation pipe section 30 is connected to the main body outer wall 20
A gap serving as an exhaust gas flow path 25 is provided between the two. In order to facilitate welding of the closely arranged evaporator tubes 32 to the header 31, a small diameter metal fitting 32a is welded to the upper end of the evaporator tube 32 as shown in FIG. I am trying to weld it to 31. Further, the small-diameter hardware 32a is provided with a throttle 33 in order to stabilize the flow in the parallel evaporation tubes 32. Note that in order to facilitate welding, the end of the evaporation tube 32 itself may be narrowed to a small diameter. In this case, the throttle is formed on the tube wall 31a of the header 31. Also, small diameter hardware 32
a. In the same way as between the evaporation tubes 32, which will be described later, a connecting plate is inserted into the gap between the small diameter parts of the throttle and welded for a gas-tight seal.

The upper parts of the evaporation tubes 32 may be directly connected to each other as shown in FIG. 3, or connected to a connecting plate 3 as shown in FIG.
4 and is gas-tightly sealed and welded to form a cylindrical shape. A combustion chamber A is formed by lining the inside of the upper end with a refractory material 21 to stabilize combustion, and the evaporator tube 32 shielded by the refractory material 21 is given the function of an economizer. . The lower part of this combustion chamber A is a radiant heat transfer section B. The lower end portions of the evaporator tubes 32 are not connected to each other but are separated, and are bent outward to form a diameter-enlarged evaporation tube portion 35 so as to be spaced apart from each other to form a passage for combustion exhaust gas. At this enlarged diameter portion 35, the two evaporation tubes 32, 32 are combined into one evaporation tube 36, as shown in FIG. The evaporation pipe 36 is U-bent inwardly upward, then further inwardly downwardly U-bent, and connected to the steam collecting pipe 40.
In this way, the convection heat transfer section C whose cross section is shown in FIG.
is formed. In this case, the U-bends of the evaporator tubes 36 are of two types: one in which the radial spacing between the evaporator tubes in the cross section is far apart, and the other in which the spacing is narrow, and the two types are arranged alternately in the circumferential direction. .
This makes it possible to arrange a large number of evaporation pipes 36 within a narrow cross-sectional area, and also to control the connection position of the evaporation pipes 36 to the upper end tube plate 41 of the steam collecting pipe 40, as shown in FIG. They are spaced apart from each other to facilitate welding.

A flange 23 is welded to the upper end of the steam collecting pipe 40, and the lower end of an inner cylinder 24 surrounding the end of the evaporation pipe 36 is welded to the flange 23, with the upper end left free. On the other hand, an expansion joint 22 is provided between the lower end of the main body outer wall 20 and the flange 23 to absorb the difference in thermal expansion between the main body outer wall 20 and the evaporation tube.
It is designed to provide a seal from the outside world.

Next, the operation of the device of the present invention will be explained. The mixture of fuel and air ignited by the combustor 10 almost completes combustion within the combustion chamber A surrounded by the refractory material 21. The high-temperature combustion gas that has almost completed combustion undergoes radiation heat transfer heat exchange with a large number of evaporator tubes 32 closely arranged in a cylindrical shape in the radiation heat transfer section B following the combustion chamber A, and then is transferred to the convection section at the bottom. It reaches the heat transfer section C, where it flows parallel to the tube axes of the evaporation tubes 32 and 36 and performs convective heat transfer heat exchange. After reaching the lower end, the combustion gas passes through the passage formed in the enlarged diameter section 35, makes a U-turn, passes through the combustion exhaust gas passage 25 formed between the evaporation pipe section 30 and the main body outer wall 20, and enters the combustion chamber A. The supplied water is heated in an economizer section outside the main body, and then discharged through an exhaust gas pipe (not shown) provided at the upper end of the outer wall 20 of the main body after the water has cooled down sufficiently.

The water supply enters the header 31 from a water supply pipe (not shown), is stably fed to a large number of evaporation pipes 32 by a throttle 33 provided between the water supply pipe 32 and the evaporation pipe 32, and first passes through the economizer. heated in the area. Subsequently, it flows through the evaporation tube 32 and is heated in the radiation heat transfer section B and the convection heat transfer section C, becoming steam (usually steam dryness around 80%) and passing through the collecting pipe 40 through a check valve (not shown). It is supplied into the wellbore through a

The bottom-hole steam generator of the present invention is as described above, and has the following effects.

(1) By arranging the heat transfer surfaces closely, the outer diameter can be reduced, and by bending the evaporation tube in the vertical direction, the length can be shortened.

(2) Combustion is stabilized by providing a combustion chamber surrounded by refractory material above the evaporator tube, and an economizer section is formed outside the combustion chamber to facilitate heat exchange with the combustion exhaust gas. This can accelerate the reduction of the exhaust gas outlet temperature and avoid the problem of bottom temperature corrosion of the exhaust gas conduit.

(3) By providing a restriction between the water supply header and the evaporator pipe, the flow in the parallel once-through evaporator pipe can be stabilized.

[Brief explanation of the drawing]

The drawing shows one embodiment of the device of this invention.
Figure 1 is a longitudinal sectional view, Figure 2 is an enlarged longitudinal sectional view of the connection between the header and the evaporator tube, and Figures 3 and 4 are different connection states of the evaporator tube in the - arrow direction of Figure 1. FIG. 5 is a partially enlarged sectional view showing - of FIG. 1.
6 is an explanatory view showing the joined state of the evaporation tubes in the direction of the − arrow in FIG. 1, and FIG. 7 is an enlarged cross-sectional view in the direction of the arrow
FIG. 2 is an enlarged sectional view taken in the direction of the - arrow in the figure. 10... Combustor, 20... Main body outer wall, 21...
Refractory material, 22... Expansion joint, 25... Exhaust gas flow path, 30... Evaporation pipe section, 31... Header, 32,
36... Evaporation pipe, 33... Throttle, 34... Connection plate, 35... Expanded diameter section, 40... Steam collecting pipe, 41
...Tube sheet, A... Combustion chamber, B... Radiation heat transfer section, C
...Convection heat transfer section.

Claims (1)

[Scope of Claims] 1. A cylindrical main body outer wall having a combustion exhaust gas outlet at the upper end, a combustor provided at the upper center of the main body outer wall, and an inner circumferential surface of the outer wall within the main body outer wall. A cylindrical evaporator tube section provided with a gap that forms a combustion exhaust gas flow path, and a refractory material forming a combustion chamber provided at the inner periphery of the upper end of this evaporator tube section. The evaporator pipe section is composed of a pipe section that forms a combustion exhaust gas flow path between the pipe section and a steam collecting pipe connected to the end of the evaporator pipe section. It consists of a large number of evaporator tubes that are vertically installed on this header through a throttle, and the upper portions of these evaporator tubes are interconnected to form a cylindrical shape and form a radiant heat transfer section below the combustion chamber. At the same time, the lower end portions form separated exhaust gas passages, and then a plurality of the separated evaporation tubes are combined into one, U-bent upwards inwardly, and then U-bent downwards inwardly to form a convection heat transfer section. A bottom-hole steam generator, the end of which is connected to the steam collecting pipe.