JPH0158439B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a furnace that connects an inlet of a waste heat boiler that recovers waste heat from non-ferrous smelting exhaust gas, particularly flash furnace exhaust gas containing high-temperature sulfur dioxide gas, and an outlet of the flash furnace that discharges the exhaust gas. Relating to an exit flue device.

Generally, in nonferrous metal smelting, blast furnaces, flash furnaces, reverberatory furnaces, fluidized roasting furnaces, etc. are used, and these furnaces are used to process nonferrous metal ores such as copper,
A method is used in which sulfides such as zinc, lead, and nickel are roasted or smelted. At this time, it is also common practice to recover the sensible heat of the combustion exhaust gas generated in the roasting or smelting of these sulfides as steam using a waste heat boiler.

The following problems arose when operating these waste heat boilers. In other words, the exhaust gas generated in nonferrous metal smelting is at a high temperature of 900 to 1300°C, and the concentration of sulfur dioxide gas in the exhaust gas is also high.
Because it contains high concentration of low melting point compounds such as Pb and Zn as dust, when the exhaust gas is introduced into the waste heat boiler, these low melting point dusts adhere to the heat transfer tubes of the waste heat boiler, and The temperature of the exhaust gas is high, and the dust is oxidized by free air and is fused to the heat exchanger tube. The dust of low melting point compounds is highly sticky and difficult to remove, which reduces the thermal conductivity of the heat exchanger tubes.If the tubes are operated for a long period of time, the dust will continue to weld and eventually close the gaps between the heat exchanger tubes, increasing the gas passing pressure loss. However, in order to maintain boiler operation, they have no choice but to take measures such as shutting down operations to clean boiler dust and reducing operating levels, resulting in economic losses.

In particular, flash-smelting furnaces used for copper or nickel smelting are
Compared to other smelting furnaces such as reverberatory furnaces and blast furnaces, it has better thermal efficiency because it instantaneously suspends smelting of powdered ore, and therefore requires less auxiliary fuel such as heavy oil.
The high concentration of sulfur dioxide gas has the advantage of easy recovery of sulfur, but on the other hand, flash furnace exhaust gas has a high dust content of approximately 100g/ ^Nm3 and is heated to temperatures between 1250 and 1300℃.
Due to the high temperature of the furnace, dust is fused to the flue device at the furnace outlet and the heat transfer tube inside the boiler, and the fused dust cannot be removed by normal soot blowing or hammering, so the exhaust gas passage is narrowed and ventilation resistance is reduced. This can lead to problems such as poor heat transfer, and eventually, problems caused by such boiler dust can lead to a reduction in operating efficiency, and ultimately, the smelting operation has to be suspended. It had The furnace outlet flue device that connects the outlet of the flash furnace and the inlet of the waste heat boiler is generally of the uptake type, and is made of fireproof bricks such as basic bricks such as maguro and magnesia. At the inlet of the heat boiler, a burner is lit to dissolve dust attached to the flue, so the temperature is 1250-1300℃.
The temperature is extremely high, which can cause the drawbacks mentioned above.

As a furnace outlet flue device for solving the above-mentioned drawbacks, there is a furnace outlet water-cooled flue device shown in Japanese Utility Model Publication No. 53-38644. The water-cooled flue device described above is shown in FIGS. 1 and 2. This system essentially adopts a water-cooled jacket system, and consists of a plurality of water-cooled flue members each having a cooling water conduit defined by an inner wall 7 made of cast steel or steel plate and an outer wall 8 made of steel plate. Each outer wall 8 is a water-cooled flue device at the furnace outlet, characterized in that it has an expansion margin made of a curved portion and has a soot blower or air lancing hole. The gas temperature is lowered by the cooling water flowing through this device, avoiding troubles caused by dust adhering to the boiler, and dust adhering to the jacket surface can be easily removed by cooling from the wall and operating the soot blower. be. Although the device of the present invention is very effective in avoiding dust problems in boilers, on the other hand, it has a major drawback in that it lowers the gas temperature at the boiler inlet, making it necessary to sacrifice waste heat recovery.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a flash flue outlet flue device that is free from dust troubles and has a high waste heat recovery rate.

That is, as a result of repeated various tests in order to convert the flash flue outlet flue device into a boiler, the inventor of the present invention succeeded in making the surface in contact with the gas smooth and measuring and managing the surface temperature of the surface in contact with the gas. Alternatively, the present invention was completed by discovering that by providing a hammering device in addition to air lancing, it is possible to facilitate the removal of adhering dust, which is the object of the present invention, and to improve heat recovery compared to the conventional method.

The gist of the present invention is to provide a vertical upward flue device installed at the opening of a setter section of a flash furnace, including a water cooling section consisting of a cooling water pipe member attached to the furnace in contact with the outlet of the setter section, and a water cooling section concentric with the water cooling section. In a boiler section in which the entire or part of the furnace outlet flue, which is axial and communicates vertically upward with the waste heat boiler, consists of a boiler member and a dust removal device, the boiler heat transfer surface is divided into small sections, and between the sections is divided the boiler heat transfer surface into small sections. This flue device is characterized in that a water-cooling jacket is provided at the boiler heat transfer surface and a dust removal device is provided at each of the boiler heat transfer surface and the water-cooling jacket.

Comparing the temperature of the water cooling jacket surface and the boiler wall surface, the former is 100-150℃, while the latter is 100-150℃.
The temperature is 260 to 330°C, and the cooling effect of dust adhering from the wall is smaller when a boiler is used compared to a water-cooled jacket, but it is possible to weld a boiler tube with a smooth surface (for example, an omega-shaped tube), etc. by means such as welding. By joining them together, creating a smooth surface, and installing the appropriate dust removal equipment mentioned above, adhering dust can be removed in much the same way as with a water-cooled jacket. An effective method is to divide the boiler heat transfer surface into small sections and use a water-cooled jacket method in which a dust removal device such as a soot blower is installed between the sections.The dust adhering to the water-cooled jacket section can be removed by the cooling effect. easy. Dust attached to the boiler section is prevented from growing uniformly along the circumference of the inner surface of the boiler, and becomes intermittent with cuts in the middle. Therefore, dust from hammering equipment, etc., is removed from the boiler section, which is divided into small sections. Dust can be easily removed by installing a removal device.

What is important to achieve the purpose of the present invention is
The purpose is to understand the state of dust adhesion and remove it effectively. As a method for this purpose, in the present invention, a sheathed thermocouple (for example, CA) whose tip is protected with a heat-resistant metal such as a boiler steel plate or stainless steel is attached to the fin portion of the boiler tube of the boiler section.
By embedding it, the surface temperature on the gas contact side is measured and managed. In this case, the surface temperature will be about 330 degrees Celsius if there is almost no dust attached, and about 260 degrees Celsius if there is a thick layer of dust, and the temperature will change within this temperature range, making it possible to accurately estimate the state of dust attachment. In the conventional water cooling jacket method, the dust adhesion status was estimated based on the temperature difference between the cooling water drain and the inlet water, but this method is more accurate due to the fact that there are no errors due to fluctuations in the amount of cooling water, and changes in the temperature difference itself are small. However, by adopting this method, it is possible to ascertain the adhesion status of the boiler, so it is possible to detect the dust adhesion status of the entire furnace outlet flue system, and it is possible to remove dust with the same effect as the conventional water-cooled jacket method. It is something that can be given. Surface temperature measurement points are appropriately installed, these measured temperatures are compared with set temperatures, and the soot blower and hammering device are operated under computer control to effectively remove dust.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a front sectional view of an embodiment of the furnace outlet flue device of the present invention, FIG. 4 is a developed view taken from the - part of FIG. 3, and FIG. 5 is a section taken from the part of FIG. 4. FIG.

1 is a flash furnace setter section; 2 is a vertically upward furnace outlet flue device installed in the opening of the flash furnace setter section;
It communicates with The furnace outlet flue device 2 includes a water-cooled part consisting of a copper furnace cooling water pipe member 3 attached in contact with the flue inlet, that is, the furnace outlet, and a water-cooled part made of a copper furnace cooling water pipe member 3, which is attached to the upper end of the cooling water pipe 3 and is concentric with the cooling water pipe 3 and directed vertically upward. It consists of water-cooled flues 4, 5, and 6 extending vertically upward, and boiler sections 7, 8, and 9 (9 being the ceiling) extending vertically upward and concentrically. The water-cooled flues 4, 5, and 6 are conventional water-cooled jacket-type flues, and the structure of the boiler sections 7, 8, and 9 is such that the boiler tube member 15 with the gas contact surface 16 is flat or curved (for example, an omega-shaped tube). The gas contact surface 16 is machined using a grinder or the like to make it smooth, and the non-contact gas surface 17 is covered with a steel plate 18.
and a soot blower 10 whose insulation is strengthened by filling a fireproof insulation castable 19 between the steel plate 18 and the steel plate 18.
It has a structure that combines a water cooling jacket 12 with lancing holes and inspection holes 11. Further, a hammering device 13 is provided in the boiler sections 7, 8, and 9 to effectively remove dust.

In addition, in order to measure the surface temperature of the gas contact side 16 of the boiler part, a hole of 8 mm diameter is cut in the center of the joint of the fin part 20 of the boiler tube member 15, and the tip is made of heat-resistant metal such as boiler steel or stainless steel. The metal sheathed CA thermocouple 21 with the completed protective cap 22 is embedded and fixed by welding. The area around the sheath thermocouple 23 is filled with a cotton-like heat-insulating material instead of a fire-resistant heat-insulating castable in order to avoid damage to the thermocouple due to vibrations caused by vibrations of a hammering device or the like. Boiler section 7, 8, 9
Like the water-cooled flue members 4, 5, and 6, the water-cooled jacket part 12 that connects the small compartments has an inner wall made of a heat-resistant material such as cast steel or a steel plate, and an outer wall made of a steel plate, and the outer and inner walls are welded or otherwise connected. It is fixed by a suitable method, and the upper and lower ends protrude outward in the radial direction to form a flange. A curved portion is provided near each end of the outer wall to provide an expansion margin for thermal stress and prevent damage to the outer wall. The water-cooled jacket of the boiler section 7 passes part of the waste water from the water-cooled flues 4, 5, and 6, and the water-cooled jacket of the boiler section 8 passes the waste heat boiler A and the feed water for the boiler sections 7, 8, and 9. Preheating.

14 is an opening provided on the side of the upper end of the furnace outlet flue device 2, and the opening 14 is in operational communication with the waste heat boiler A.

In this embodiment, a part of the furnace outlet flue that communicates with the boiler is converted into a boiler, but the boiler section is directly connected to the water cooling section made of the cooling water pipe member and extends vertically upward with concentric shafts. It goes without saying that it may be connected to the waste heat boiler A, and is not limited to this embodiment.

When the apparatus shown in FIGS. 4 to 6, which is an embodiment of the present invention, is applied to copper smelting using a flash furnace, the steam generated from the boiler sections 7, 8, and 9 is transferred to the steam system of the conventional waste heat boiler A. The power output was increased by approximately 10%.

The specifications and results of the boiler section according to the present invention are as follows.

Maximum working pressure 52Kg/cm ² Normal pressure 48Kg/cm ² Water supply temperature 110℃ Steam temperature 262.7℃ Heat transfer area 44m ² Steam generation amount 3.2t/h As detailed above, the flue device at the outlet of the flash furnace according to the present invention This invention enables smooth operation of flash furnaces and shows excellent results in terms of effective use of energy, so it can be said to be an extremely useful invention.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a conventional furnace outlet flue device, FIG. 2 is a partially enlarged view of the portion shown in FIG. 1, and FIG. 3 is an embodiment of the furnace outlet flue device of the present invention. 4 is a front sectional view of the example, FIG. 4 is a developed view taken from the - section in FIG. 3, and FIG. 5 is a partially enlarged sectional view taken from the section shown in FIG. 4. 1... Furnace settler section, 2... Furnace outlet water-cooled flue device, 3... Furnace outlet water-cooled pipe, 4, 5, 6... Water-cooled flue, 7, 8, 9... Water-cooled flue boiler section, 10
... Soot blower, 11 ... Lansing hole and inspection hole, 12 ... Water cooling jacket part, 13 ...
... Hammer device, 14 ... Flue outlet, 15 ... Boiler tube, 16 ... Gas contact surface, 17 ... Gas contact surface, 18 ... Boiler part outer plate, 19 ... Fireproof insulation castable, 20 ... Finn club, 21...
Sheath thermocouple, 22... protection tube, 23... heat insulating material.

Claims (1)

[Scope of Claims] 1. A vertical upward flue device installed at the opening of a setter section of a flash-smelting furnace, comprising: a water-cooled section consisting of a cooling water pipe member attached to the furnace in contact with the outlet of the setter section; and the water-cooled section. In the boiler section, in which all or part of the furnace outlet flue, which is concentric with and communicates vertically upward with the waste heat boiler, is composed of boiler members and a dust removal device, the boiler heat transfer surface is divided into small sections, and the boiler heat transfer surface is divided into small sections. 1. A flue device at outlets of flash-smelting furnaces, characterized in that a water-cooling jacket is provided between the boiler heat transfer surface and the water-cooling jacket, and a dust removal device is provided on each of the boiler heat transfer surface and the water-cooling jacket. 2. The boiler member is made by welding boiler tubes whose surfaces in contact with gas are machined into a flat or curved shape, covering the gas surface of the boiler tubes with a steel plate, and connecting the steel plate with the gas surface opposite to the gas surface. 2. The flue device according to claim 1, characterized in that a heat insulating material is filled between the self-smelting furnace and the self-smelting furnace. 3. The flash-melting furnace outlet flue device according to claim 2, characterized in that a thermocouple for measuring the surface temperature of the surface in contact with gas is embedded in the boiler tube fin portion of the boiler member. 4 A water-cooled section consisting of a cooling water pipe member attached to the furnace in contact with the outlet of the settler section, and an inner wall made of cast steel or steel plate and an outer wall made of steel plate, which are in contact with the water-cooled section and extend vertically upward in a concentric manner. Claim 1: The invention is comprised of a plurality of water-cooled flue members having cooling water conduits, and a boiler section that abuts the water-cooled flue members and includes a boiler member and a dust removal device. Flash furnace outlet flue device as described in Section 1. 5. Claims characterized in that the boiler section is constituted by a water cooling member having a cooling water conduit defined by a boiler member, a dust removal device, an inner wall made of cast steel or a steel plate, and an outer wall made of a steel plate. The flash-melting furnace outlet flue device according to item 4.