RU206530U1 - Low Power Consumption Bulk Material Heat Treatment Device - Google Patents

Abstract

A device (1) for heat treatment of bulk material in the drying zone, preheating zone, firing zone and cooling zones, including a closed moving grate (4) with moving links, grate carts (3), each of which consists of a frame with wheels and grate bars located on the crossbars, and blow chambers (20, 20 ', 21, 21', 22, 22 ', 30, 30', 31, 40, 40 ', 41, 42, 47, 48), which are located so, that the gas flows through the grates (3) and their grates from the blast chambers or into the blast chambers (20, 20 ', 21, 21', 22, 22 ', 30, 30', 31, 40, 40 ', 41, 42 , 47, 48). In this case, from the blast chamber (40, 42) in the cooling zone, which is installed downstream of the first blast chamber (41) of the cooling zone and which sucks in the cooling gas medium, the cooling gas is recirculated through the recirculation pipeline (50, 51, 52), equipped with fan (94), into one blast chamber (20 ') of the drying zone. Downstream of the fan (94) there is a bypass line (96) leading back to the blast chamber (47) of the first cooling zone, injecting a gaseous medium. In this case, the bypass pipeline and the recirculation pipeline contain a pressure control valve (55, 97), which allows the cooling gas to be removed as an exhaust gas, so that each of the bypass pipeline (96) and the recirculation pipeline (50, 51, 52) has one valve ( 55, 97) pressure control, and the pressure control valves (55, 97) in the bypass line (96) and the recirculation line (50, 51, 52) lead to a common outlet line (91, 93).

Description

Technology area

The utility model relates to a device for heat treatment of bulk materials, in which bulk material is fed into at least one drying zone, one preheating zone, one firing zone and a cooling zone by means of a chain of a moving grate, rotatable in the direction of travel, including a closed grate with moving links, grate carts, each of which consists of a frame with wheels and grates located on the crossbars, and the gas passes through the grate carts and their grates from the blast chambers or into the blast chambers, and from the blast chamber to the cooling zone, which is installed downstream of the first blast chamber of the cooling zone and which sucks in the cooling gas medium, the cooling gas is recirculated through a recirculation pipeline equipped with at least one fan into one blast chamber of the drying zone.

In devices for roasting or sintering granules, the bulk material to be processed, such as, for example, iron ore, iron oxides or also zinc ore, is loaded onto the grate carriages. Such grate carriages consist of a frame provided with wheels and consisting of end parts and crossbars, and grate bars located between the crossbars. A plurality of such grate carriages form a closed chain of grate carts, which is also called a moving grate.

For example, in FIG. 1 shows an apparatus 1 for roasting iron ore granules, in which the present utility model is used in this case. At the feeding section in front of the bell 2, the bulk material is loaded onto the grate carts 3, forming a closed chain of grate carts, which is called the moving grate 4. Under the bell 2, the bulk material transported on the grate carts 3 passes through a number of heat treatment sections. In more detail, these areas are:

1 - loading area,

2 - the first drying zone,

3 - the second drying zone,

4 - pre-firing zone,

5 - firing zone,

6 - zone of subsequent firing,

7 - cooling zone and

8 - exit zone.

In these zones, the grate carriages are loaded with material, the bulk material is dried, preheated, fired and then cooled again. In the processing areas under the hood 2, the moving grate is guided along the carrying track 5 of the continuous conveyor 6, while the rollers 7 of the grate carriages 3 are guided between the inner guide rail 8 and the outer guide rail 9. The movement of the moving grate 4 is carried out through the driving or lifting wheel 10, made in the form of a gear wheel and engaging with its hollows between the teeth (recesses 11) the rollers 7 of the grate carts 3.

After passing through the hood 2, the grate carriages 3 of the moving grate 4 reach the unloading area, which is fixed to the lowering or output wheel 13 of the continuous conveyor 6. As in the case of the lifting wheel 10, on the lowering wheel 13, the cavities 14 between the teeth of the output gear wheel engage with rollers 7 grate carts 3. The grate carriages 3 are tilted so that their load is dropped by gravity. Since the grate carriages 3 are guided by means of an external guide rail 9, they do not fall down themselves, but return to the lifting wheel 10 upside down along the lower track 15 of the continuous conveyor 6. Under the hood 2 there are blowing chambers 16 that provide a controlled gas flow. In the area of the carrier track 5, the grate carriages 3 move between the upper hood 2 and the lower blast chambers 16 without colliding with the components of the cap 2 or the blast chambers 16.

During normal operation, the moving grate 4 rotates endlessly on the continuous conveyor 6 and moves the bulk material to be processed through the processing areas under the hood 2 before being discharged into the discharge area and further processed in a manner not described in detail herein.

As already noted, in two drying zones, a preheating zone, a firing zone, a post-firing zone and a cooling zone, the bulk material contained in the grate carts is subjected to heat treatment due to the fact that hot or cold gas enters either from the blast chamber through the free-flowing layer into the grate into the hood, or from the hood through the free-flowing layer in the grate into the blast chamber. In the loading area and the exit area, no flow prevails.

In order to increase the energy efficiency of such grizzly carts, the heated gas streams are often recirculated, for example the firing off-gases are recirculated to the drying and / or preheating stage. Other concepts for heat recirculation are described in EP 1 974 066 B1 and DE 195 13 549 B4.

DE 4234085 A1 shows a two-section cooling zone with recirculation from the second section to the first cooling section and the drying zone through pipelines.

DE 1433339 describes a cooling zone divided into two sectors, whereby the air from the second sector is partly recirculated to the first cooling sector and partly to the drying stage. In addition, DE 1433339 describes a conduit for recirculating gas from a first cooling sector to a preheating stage. However, this energy concept does not affect the cost of electricity and capital costs, since two fans are needed to control the pressure and mass flow rate of the gas in the blast chambers to which the gas is recirculated. Thus, the total energy consumption directed to the final thermal electrical energy is still high.

In this context, the aim of the present utility model is to reduce the overall energy requirements of granulation devices.

This goal is achieved using a device in accordance with the features of claim 1 of the utility model formula.

Such a device is made with the possibility of performing a method that is aimed at improving the cooling of devices for granulation, namely, to a cooling stage with two independent bell sections and a bypass pipeline that passes exhaust gases from the last cooling stage not only to the drying stage, but also to the first cooling stage. where a common fan is used.

In more detail, a method for heat treating bulk material includes processing in at least one drying zone, one preheating zone, one calcining zone, and two cooling zones. Bulk material is passed through these zones using a chain of a moving grate, made with the possibility of turning in the direction of movement, containing an endless moving grate with moving links, grate carts, each of which consists of a frame with wheels and grates located on the crossbars. Bulk material is loaded onto the grate carts. Heat treatment is provided with the help of gas flowing through the grate carts and their grates from the blast chamber or into the blast chamber, while the direction of the gas flow from the injection blast chamber installed above or below the grate to the suction blast chamber refers to different zones. As for the cooling zone, it should be noted that it contains at least two pairs of blast chambers (two upper and two lower). From the blast chamber in the cooling zone, which is installed downstream of the first blast chamber of the cooling zone and which sucks in the cooling gaseous medium, the cooling gas is recirculated through a recirculation pipe containing at least one fan into one blast chamber of the drying zone.

An essential part of the utility model is that, downstream of the fan parts of the cooling hood 2, the exhaust gas is discharged through a bypass pipeline and sent back to the blast chamber of the first cooling zone by blowing in a gaseous medium. In addition, the cooling gas in the recirculation and bypass lines is controlled by at least one pressure control valve in each line, which allows the cooling gas to be diverted as waste gas. Thus, only one fan can be used, but it is possible to meet the different technological requirements of the blast chambers to which the gas is recirculated. As a result, capital and operating costs are reduced, which also translates into economic and environmental benefits.

In a preferred embodiment of the invention, the cooling off-gas is recirculated from the last blast chamber of the cooling zone, which draws in the cooling medium. In this way, the temperature difference with the first cooling zone in which parts of the gas are recirculated and, as a consequence, the heat effect of the recirculation is maximized.

Also preferably, the recycle gas has a temperature of 280 to 420 ° C which best suits the requirements of the drying zone and the first cooling zone.

In this connection, it is also preferable to supply gas at a temperature of 160 to 200 ° C to a blast chamber which is separate from the blast chamber from which the gas stream is recirculated.

It is most efficient to use ambient air as the cooling gas, as it is available at no additional cost.

In addition, preferably, the recirculation line and / or the bypass line is negative pressure for safety reasons.

To further increase the energy efficiency of the method, gas is recirculated as a heat carrier from the first cooling zone to the preheating zone and / or from the first cooling zone to the burning zone and / or from the preheating zone to the drying zone and / or from the burning zone to the preheating zone. Each recirculation provides at least partial heat recovery.

Such a device for heat treatment of bulk material includes at least one drying zone, one preheating zone, one burning zone and at least two cooling zones. In addition, it contains a chain of a moving grate, made with the possibility of turning in the direction of movement, containing a closed moving grate with moving links, grate carts, each of which consists of a frame with wheels and grates located on the crossbars. To create a gas flow through the grate carts and their grates, the blast chambers are placed so that the gas flows from the blast chambers or into them. In the context of the invention, the already mentioned blast chamber is characterized by at least two cooling zones, and from the blast chamber in the cooling zone, which is installed downstream of the first blast chamber of the cooling zone and which sucks in the cooling gas medium, the cooling gas is recirculated through the recirculation a pipeline containing at least one fan into one blast chamber of the drying zone.

The utility model is characterized by a bypass pipeline that branches off downstream of the fan and leads back to the blast chamber of the first cooling zone, injecting the gaseous medium. In addition, each of the bypass line and the recirculation line contains at least one pressure control valve, which allows the cooling gas to be withdrawn as waste gas. Thus, the overall energy efficiency, including thermal and electrical energy, is increased.

In a preferred embodiment, the fan is an upflow drying fan (UDD fan). The UDD fan provides the required volume of gas for the first stage of drying and regulates the pressure in the hood of the second cooling zone.

Also preferably, the cooling zone comprises two cooling zones with two upper and two lower blast chambers. In this way, the present concept achieves the maximum rate of energy recycling.

In another preferred embodiment, the pressure control valves in the bypass line and the recirculation line lead to a common outlet line. Thus, only one hood exhaust fan and fewer piping are required, further reducing capital and operating costs.

Other features, advantages and possible areas of application of the utility model follow from the description of the drawings below. In this document, all the features described and / or shown form, independently or in an arbitrary combination, the subject matter of the utility model, regardless of their summary in the claims of the utility model or their references.

The drawings show:

figure 1 shows the design of a moving grate;

in fig. 2 shows a first flow diagram of a method according to the prior art;

in fig. 3 shows a second flow diagram of a method according to the prior art;

in fig. 4 shows a technological scheme in accordance with the present utility model.

FIG. 1 has already been explained in detail and shows the basic arrangement of the moving grate, also as the basis of the present utility model.

FIG. 2 shows in more detail the various zones of the pellet calcining apparatus 1 and the corresponding blow chambers and their conduits. The grate 3 passes through the first and second drying zones with the respective upper blast chambers 10 and 11, as well as the lower blast chambers 10 'and 11'. From there, it enters a preheating zone with an upper blast chamber 20 and a lower blast chamber 20 '.

Downstream of the described pretreatment, there is a firing zone with an upper blast chamber and a lower blast chamber. As a feature, the firing zone is characterized by a second upper blast chamber 31 connected to a lower blast chamber 30 'for subsequent firing.

Finally, the bulk material loaded onto the grate passes through various cooling zones, which, for example, have three upper blast chambers 40, 41 and 42 and one lower blast chamber 40 '. Fresh air is fed through lines 60, 62 and fan 61 into the lower blast chamber 40 'and blown through the bulk material into the upper suction blast chamber 40, 41 and 42.

The off-gas blown out from the first upper blast chamber 41 of the cooling zone is fed through a conduit 32 to the upper blast chamber 31 for calcination for subsequent calcination. From the second upper blast chamber 40, exhaust gas is recirculated through lines 80, 81 and 82 to the upper blast chamber 30 for calcination and the upper blast chamber 22 for preheating. Off-gas from the third blast chamber of the cooling zone 42 is recirculated through conduit 50, fan 51 and conduits 52, 53 to the first lower blast chamber 20 'of the drying zone. Portions of said recirculated gas are withdrawn through conduit 54 and passed through valve 55 and conduit 56 into conduit 12.

The collected off-gas from the first upper blast chamber 10 of the first drying zone and said conduit 56 is fed into conduit 90 and blown out through fan 01 and conduit 92.

The calcining off-gas is recirculated through conduit 70, fan 71 and conduit 72 to the lower blast chamber 22 'of the preheating zone.

Off-gas from the lower blast chambers 21 'of the second drying is discharged through conduit 73, fan 74 and conduit 75, while off-gas from the lower blast chamber 22' of the preheating zone is discharged through conduits 76 and 78 and the corresponding fan 77. Both off-gases are collected in pipeline 79.

FIG. 3 shows another possibility of improving energy efficiency already found in the prior art. In this case, the cooling zone has four upper blast chambers 40, 41, 42 and 43 and three lower blast chambers 44, 45 and 46, the lower blast chamber 46 corresponding to the upper blast chambers 42 and 43.

From the upper blast chamber 46 of the cooling zone, which the bulk material passes last, the heated exhaust gas is discharged and recirculated through conduit 56, fan 57 and conduit 58 as a cooling medium into the lower first blast chamber 44 of the cooling zone.

In addition, the other two lower blast chambers 45 and 46 of the cooling zone have a separate supply of cooling gas, through the conduit 60, the fan 61 and the conduit 62 for the blast chamber 45 and through the conduit 63, the fan 64 and the conduit 65 for the blast chamber 46.

FIG. 4 shows the present utility model. Thus, only three upper blast chambers 40, 41 and 42 are provided, as well as two lower blast chambers 47 and 48, without a direct correlation between the upper and lower blast chambers.

The partially heated exhaust gas is withdrawn via line 50 from the blast chamber 42 of the cooling zone, through which the bulk material passes last. The heat-transferring gas is pressurized in the fan 94. Through the bypass line 96, the gas is partially introduced into the first lower blast chamber 47 of the cooling zone. The bypass line 96 contains a control valve 97.

The remaining gas stream is recirculated through lines 95, 51 and line 52 to the first lower preheating blast chamber 20 '. The pressure and flow rate in line 52 is controlled by valve 55 through lines 53, 54 to line 90.

List of symbols:

1 - device for burning pellets

2 - cap

3 - grate cart

4 - moving grate, grate chain

5 - carrier track

6 - continuous conveyor

7 - roller of the grate

8 - inner guide rail

9 - outer guide rail

10 - lifting or driving wheel

11 - cavities between the teeth

13 - lowering or output wheel

14 - cavities between the teeth

15 - lower track

20 - the first upper blast chamber of the drying zone

20 '' - the first lower blast chamber of the drying zone

21 - the second upper blast chamber of the drying zone

21 '- the second lower blast chamber of the drying zone

22 - upper blast chamber of the preheating zone

22 '- lower blast chamber of the preheating zone

30 - the first upper blast chamber of the firing zone

30 '- lower blast chamber of the firing zone

31 - second upper blast chamber of the firing zone

40 - the second upper blast chamber of the cooling zone

41 - the first upper blast chamber of the cooling zone

42 - the third upper blast chamber of the cooling zone

43 - fourth upper blast chamber of the cooling zone

40 '- lower blast chamber of the cooling zone

44 - the first lower blast chamber of the cooling zone

45 - the second lower blast chamber of the cooling zone

46 - the third lower blast chamber of the cooling zone

47 - the first lower blast chamber of the cooling zone

48 - the second lower blast chamber of the cooling zone

50 - pipeline

51 - fan

52-54 - pipeline

55 - control unit

60 - pipeline

61 - fan

62 - pipeline

70 - pipeline

71 - fan

72, 73 - pipeline

74 - fan

75, 76 - pipeline

77 - fan

78, 79 - pipeline

80-84 pipeline

75, 76 - pipeline

77 - fan

78, 79 - pipeline

80-84 - pipeline

90, 91 - pipeline

92 - fan

93 - pipeline

94- fan

95, 96 - pipeline

97 - control unit

98 - pipeline.

Claims (4)

1. Device (1) for heat treatment of bulk material in the drying zone, preheating zone, firing zone and in cooling zones, including a closed moving grate (4) with moving links, grate carts (3), each of which consists of a frame with wheels and grates located on the crossbars, and blow chambers (20, 20 ', 21, 21', 22, 22 ', 30, 30', 31, 40, 41, 42, 47, 48), which are located with the possibility gas flow through the grate carts (3) and their grates from the blast chambers or into the blast chambers (20, 20 ', 21, 21', 22, 22 ', 30, 30', 31, 40, 41, 42, 47, 48 ), and at the same time the blast chamber (40, 42) in the cooling zone, which is installed downstream of the first blast chamber (41) of the cooling zone, is configured to suck in the cooling gas medium, allowing the cooling gas to be recirculated through the recirculation pipeline (50, 51 , 52), equipped with a fan (94), into one blast chamber (20 ') of the drying zone, characterized in that downstream of the fan (94), a bypass pipeline (96) is diverted, leading back to the blast chamber (47) of the first cooling zone, made with the possibility of injecting a gaseous medium, and the bypass pipeline and the recirculation pipeline contain a control valve (55, 97) pressure, which allows the cooling gas to be removed as waste gas, so that each of the bypass line (96) and the recirculation line (50, 51, 52) has one pressure control valve (55, 97), and control valves (55, 97) the pressures in the bypass line (96) and the recirculation line (50, 51, 52) lead to a common outlet line (91, 93). 2. A device according to claim 1, characterized in that the blast chamber adapted to recirculate the cooling gas through the recirculation pipeline (50, 51, 52) is the last blast chamber (42). 3. Apparatus according to claim 1 or 2, characterized in that the fan (94) is an upflow drying fan (UDD fan). 4. A device according to any one of claims 1 to 3, characterized in that the cooling zone comprises three upper blast chambers (40, 41, 42).

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