RU2151350C1 - Vertical shaft furnace for production of cement and other similar materials - Google Patents

Abstract

FIELD: shaft furnaces for production of cement and other similar materials. SUBSTANCE: furnace includes drum feeder for delivery of raw materials in form of granules which is mounted above layer of furnace for smooth distribution of granules of raw materials, blower mounted on furnace base for feeding the to common air manifold via pipe line; air manifold is provided with many air exhaust pipe lines; air pipe line is connected to air nozzle mounted inside reinforced casing of vertical shaft furnace; taper air nozzle is provided with device having screen with many peripheral slits for passage of air; air pipe line is connected to air box mounted above reinforced casing and provided with perforations of inner vertical wall; air pipe line is connected to air manifold equipped with nozzles for escape of air which are mounted in such way that air is fed directly under sintering zone of vertical shaft furnace; air pipe line is connected to chimney stack of vertical shaft furnace; chimney stack is fitted with throttle valve under air pipe line; chimney stack is also provided with bypass pipe line under throttle valve which is connected with cyclone separator provided with fan for exhaust of flue gases; outlet of cyclone separator is connected with discharge pipe line through scrubber; indicator with sensor is mounted on casing of shaft furnace for indication of level of burning layer; products are removed via exhaust chute. EFFECT: enhanced efficiency of roasting the materials due to smooth delivery of required amount of air to sintering zone and entrapping contaminating gases and solid particles. 2 cl, 2 dwg

Description

 The present invention relates to a new vertical shaft furnace (IDT), suitable for the production of cement and other similar materials.

 As a starting material for a vertical shaft furnace, homogenized raw material in the form of granules containing the required amount of fuel, usually finely ground coke for combustion, is used. These granules are fired in the sintering zone in the furnace and the required combustion air is supplied from below through a rotating grate. The heat generated in this way causes calcining of the limestone and recombination of the oxides forming the cement clinker. Hot clinkers are cooled in a cylindrical cooling zone with air coming from the bottom of the furnace, and then they are unloaded through a controlled discharge system with an air lock. A rotating conical grate installed in the furnace simplifies the variable discharge, crushes the resulting pieces and also distributes the air entering through its peripheral openings. At the top of the furnace is a flue gas pipe / s.

 US Pat. No. 4,332,641 discloses a vertical shaft furnace with air injection for burning carbon-containing material, for example petroleum coke, at the top of a vertical shaft to produce hydrogen and carbon monoxide, and such a gaseous product is removed from a level below the combustion zone. The device made according to this patent is not suitable for sintering or agglomeration of cement and other similar products, and its design is completely different from the design of a vertical shaft furnace in accordance with the present invention.

 Another U.S. Patent No. 4,347,120 mentions a vertical furnace for calcining heavy materials containing hydrocarbon, for example, untreated coke in the presence of steam introduced from the bottom of the furnace to produce hydrogen. Here, also, a vertical shaft furnace is not suitable for burning solid materials, such as cement, and its design is completely different from the vertical shaft furnace proposed by the present applicants.

 US Pat. No. 4,352,661 discloses a shaft furnace on which a hopper is mounted, and the thermal energy generated in the shaft furnace is used to heat the raw material located in the hopper. The design of the various means and the function of this shaft furnace is different from the design and function of the new vertical shaft furnace made in accordance with the present invention.

 US 4409068 and 4407700 describe a radially arranged injector for introducing combustion gas mounted inside a shaft furnace, and such an injector includes means for circulating refrigerant around the periphery of the injector and means for introducing circulating gas into the furnace. The system and devices disclosed in these patents are different from the new vertical shaft furnace made in accordance with the present invention.

 Another US Pat. No. 4,718,984 discloses a vertical shaft coke kiln in which a gas stream heated in a cooling chamber can be used as an accompanying gas stream for heating in the upper part of the furnace. This patent is not related to the present invention of the applicants, revealing a new vertical shaft furnace.

 Another US Pat. No. 4,747,773 discloses a vertical shaft kiln for calcining limestone and comprising a number of treatment zones. The design and function of the furnace from this patent are quite different from the new vertical shaft furnace proposed by the present applicants.

 Known vertical shaft furnaces have an air distribution system in which air is supplied from below either through annular cavities formed between the grate plates and the reinforced casing, or through peripheral and central openings formed in the grid in shaft furnaces of various designs. Since there is a long column of clinker above the grate, the air required for burning pellets in the sintering zone for complete combustion is distributed unevenly in most cases. Due to the uneven bulk density of clinkers inside the cylindrical column, a guaranteed uniform air distribution cannot be achieved. As a result, uniform clinker burning cannot be achieved in a vertical shaft furnace of known design. Also, due to lack of air in some parts of the sintering zone, unfired clinkers are formed. Since air is supplied only through the bottom of the furnace, in the known device air tends to exit along the path of least resistance, i.e., through a nozzle for discharging clinker. Because of this, not only a significant amount of air is lost, but also harmful dust (polluting the environment) is formed when the clinker is removed from the existing vertical shaft furnace. Combustion products from vertical shaft furnaces of known design contain particulate matter and other polluting gases, often above acceptable limits.

 The basis of the present invention is the creation of a vertical shaft furnace (IDT), suitable for the production of cement and other similar products, which would eliminate the disadvantages of known vertical shaft furnaces.

 The present invention relates to a vertical shaft furnace in which an appropriate amount of combustion air is supplied to the sintering zone; to simplify the uniform supply of air for the combustion of granules, a pipeline is provided for supplying secondary air at the top of the top grid area; To capture solid particles and other exhaust gases, a cyclone separator and a liquid scrubber are installed in the chimney. To ensure the initial ignition of the furnace, a bypass pipe with a throttle valve is provided, into which the required air is blown to create the thrust necessary to establish the initial and other various operating conditions of the furnace. An electronic sensor is installed in the furnace body to maintain the layer level in the furnace.

 The required amount of air for burning the raw granules is distributed in various proportions in a new furnace made in accordance with the present invention. Basically, all the required amount of air, together with the required excess amount of air, is supplied to the air manifold installed near the zone of the reinforced casing on the supporting structure of the furnace. The corresponding pipeline from the air manifold is connected to the air conical nozzle under the top of the grate plate. The secondary air pipe leading from the air manifold is connected to a circular air box protruding from the top of the reinforced casing. This air box has perforations on the inner wall for secondary air to enter the furnace. Another pipeline of the required cross section passes from the same air manifold, and it is connected to another annular air collector located immediately below the sintering zone, from which many air nozzles with the required holes protrude through the refractory lining around the sintering zone.

 Finally, another duct passes from the common manifold, connected to the chimney above the throttle. The whole device of the air distribution system containing the mentioned pipelines and a common air collector allows you to process raw materials of any composition with the correct distribution of all the required air due to the regulation of controlled valves installed in pipelines and nozzles. In a vertical shaft furnace of known design, the phenomenon of unevenness in the distribution of air resulted in burnt and unburnt granules and production losses as a result of the formation of lumps causing air channels in the critical sintering zone in the vertical shaft furnace. Thanks to the use of this new air distribution system, these problems are completely eliminated, thereby ensuring both the quantity and quality of clinkers. Due to the different moisture levels in the raw granules, a large amount of smoke associated with various other gases and particulate matter is emitted through the chimney of a vertical shaft furnace. This creates not only difficulties in operation, but also pollution problems on the working platform. To reduce this problem, the air duct, as already mentioned, is connected above the choke of the chimney to create additional traction. This helps to accelerate the emission of smoke through the chimney. Solid particles and polluting gases are captured by a cyclone separator and a liquid gas scrubber of the appropriate design installed in the flue gas emission system.

 A vertical shaft furnace made in accordance with the present invention is further associated with reference to the attached drawings, which are presented for illustration only and do not limit other possible embodiments of the present invention.

In the drawings attached to this description:
FIG. 1 (a) is a side view of a furnace containing air distribution devices, a chimney with a throttle valve, a cyclone separator and a scrubber;
FIG. 1 (b) is a plan view of an air manifold with a plurality of air inlet nozzles.

 Accordingly, the present invention is a vertical shaft furnace (IDT), suitable for the production of cement and other similar products, which contains a drum type feeder 1 (Fig. 1a) for supplying raw materials in the form of granules mounted above the layer 2 in the furnace for uniform distribution of granules raw materials, a blower 3, mounted on the base of the furnace, for supplying air through a pipe 4 to a common air manifold 5 having a plurality of exhaust air ducts 6, 9, 12 and 16, while the air duct 6 is connected to the conical air nozzle 7 installed inside the reinforced casing 11 of the vertical shaft furnace, the conical air nozzle is provided with a device 8 with a grill having a plurality of peripheral slots 30 for air, the air duct 9 is connected to the air box 10 mounted above the reinforced casing 11, the air box has perforations 31 on the inner vertical wall, the air duct 12 is connected to an air manifold 13 having nozzles 14 for air inlet (FIG. 1a), installed in such a way as to supply air directly under the sintering zone 15 of the vertical shaft furnace, the air duct 16 is connected to the chimney 17 of the vertical shaft furnace, the chimney provided with a throttle valve 18 above the air duct 16, the chimney is also provided with a bypass pipe 19 under throttle, the bypass pipe is connected through a means 20 to a cyclone separator 21, equipped with a fan 22 for exhausting flue gases, the output of the cyclone separator is connected to the exhaust pipe Gadfly scrubber 24 through 23, 25, 26, 27 and 28, switch 29 with a sensor mounted on a vertical shaft furnace body for indicating the level of the burning bed. Cement clinkers or other suitable products are removed through a discharge chute 32.

 Maintaining the level of the layer in the furnace is very important to achieve the appropriate quality and quantity of clinkers. When the layer level drops below a certain limit level, the air pressure drop also decreases, thereby causing an increase in air supply to the sintering process, resulting in the production of burnt clinkers. In addition, maintaining the layer level is also important, since the sintering operation must be limited to the conical part of the furnace. This is only possible if the layer is maintained at a given level. To constantly monitor the layer level in accordance with the present invention, a sensor with an alarm 29 is installed in the furnace. Raw granules of cement raw materials or minerals are fed through a drum feeder 1 for granules. It distributes the granules evenly over the layer 2 of the furnace. The air from the tailings of the blades of the blower 3 passes through a common pipe 4 to a common manifold 5, from which a pipe 6 for supplying primary air to the conical air nozzle 7, from which air is distributed through peripheral air slots in the device 8 of the top grate. Another duct 9 extends from the common air manifold 5 into the air box 10 above the reinforced casing 11. The inner vertical wall of the air box has perforations for air inlet. Another duct 12 extending from the same common air manifold 5 extends along the furnace wall and supplies air to the air manifold 13, from which several air nozzles 14 protrude, as shown in FIG. 1 (b), into the furnace directly below the sintering zone 15. Another air line 16 from the common air collector 5 passes into the chimney 17 downstream of the throttle 18. The bypass pipe 19 passing from the chimney pipe 17 has a flange connection 20, in which a cyclone separator 21 is connected. The flue gases drawn by the exhaust fan 22 pass, after moving through this cyclone separator, through another liquid scrubber 23, which is countercurrent with the smoke moving upward, and then the gases are piped 24 into the atmosphere, while the liquid adsorbent entering through the pipe 26 and sprayed through the nozzles 25 moves down and passes through the sealing materials 27 and finally leaves through the pipe 28. The formed clinkers move down in the presence of air that enters through various points input 6, 10 and 14. A sensor with an alarm 29 is installed in an appropriate place on the furnace body to indicate the level of the burning layer inside the furnace during its operation.

 A vertical shaft furnace, made in accordance with the present invention, has distinctive advantages in the distribution of air throughout the furnace for effective firing of granules in a wide range of fired materials of raw materials for the production of cement and similar materials. This invention also includes a device for controlling pollution at the exit of a chimney containing a scrubber and cyclone separators for trapping polluting gases and solid particles generated during the processing operation. Also, the present invention is suitable for incorporating its electronically controlled and self-regulating devices for unloading the product with blocking the air supply to control the air from the process and dust pollution.

Claims (2)

 1. A vertical shaft furnace for the production of cement and other similar materials, containing a drum feeder (1) for feeding raw materials in the form of granules, mounted above the layer (2) of the furnace for even distribution of granules of raw materials, a blower (3) mounted on the base of the furnace for supplying air through a pipeline (4) to a common air manifold (5) having a plurality of exhaust air ducts (6, 9, 12 and 16), while the air duct (6) is connected to a conical air nozzle (7) located inside the reinforced skin ha (11) of a vertical shaft furnace, a conical air nozzle (7) is equipped with a device (8) with a grill having many peripheral slots (30) for air, the air duct (9) is connected to an air box (10) mounted above the reinforced casing (11) ), the air box has perforations (31) on the inner vertical wall, the air duct (12) is connected to the air manifold (13) having nozzles (14) for air inlet, arranged so as to supply air directly under the sintering zone (15) to vertical shaft furnace the gadfly (16) is connected to the chimney (17) of the vertical shaft furnace, while the chimney is equipped with a throttle valve (18) under the air duct (16), the chimney is also equipped with a bypass pipe (19) under the throttle valve, the bypass pipe is connected through connecting means (20) with a cyclone separator (21) equipped with a fan (22) for exhausting flue gases, the output of the cyclone separator is connected to the exhaust pipe (24) through a scrubber (23, 25, 26, 27, 28), an indicator (29) with a sensor mounted on a vertical shaft housing Chi to indicate the level of the burning layer, the exhaust chute (32) is designed to remove the product.  2. The vertical shaft furnace according to claim 1, characterized in that it uses a spray type scrubber with a liquid absorbent.