CN218025864U - Two-way roasting double-chamber shaft kiln - Google Patents

Abstract

The utility model relates to a two thorax shaft kilns of two-way calcination, including rotatory loading hopper, switching flashboard, spray gun safety cover, spray gun, kiln thorax, central nozzle, ejection of compact machine and braced frame. The beneficial effects are as follows: the center nozzle is additionally arranged to realize parallel-flow roasting of the roasting kiln chamber and countercurrent roasting of the heat storage kiln chamber, the full parallel-flow roasting mode of the original double-chamber shaft kiln is adjusted to be a bidirectional roasting mode of parallel-flow roasting and countercurrent roasting, so that the heat distribution of the center and the periphery of the shaft kiln can be uniform, a plurality of problems of insufficient burning of materials and the like caused by overlarge radius of the shaft kiln chamber are solved, the product roasting quality is improved, the center nozzle is particularly suitable for large-size double-chamber shaft kilns of 800t/d and above, a new technical approach is provided for large-scale double-chamber lime shaft kilns, a new technical approach is provided for development of the double-chamber lime shaft kilns with low calorific value fuel, and the center nozzle has a wide development prospect.

Description

Two-way roasting double-chamber shaft kiln

Technical Field

The utility model relates to an industrial furnace technical field especially relates to a two thorax shaft kilns of two-way calcination.

Background

At present, domestic high-quality active lime is mostly produced by adopting a rotary kiln or a double-chamber shaft kiln. Compared with a double-chamber shaft kiln, the main defects of the rotary kiln are as follows: large occupied area, high heat consumption and NO _X (Nitrogen oxides) are seriously out of limits and it is difficult to use the heat value below 3000kcal/m alone ³ The following low heating value fuels are such as coal gas. The double-hearth shaft kiln is used as a main kiln type for producing high-quality active lime, can use liquid fuel, solid fuel and various high and low calorific value fuels, and is widely applied at home and abroad. The double-chamber shaft kiln has the characteristics of advanced process principle and low heat consumption, and is an advanced device for producing high-quality lime which is acknowledged by the lime industry. In addition, the auxiliary equipment of the double-chamber shaft kiln is mature and reliable, and the operation control of the double-chamber shaft kiln achieves high automation and intelligence. In addition, as for the double-chamber shaft kiln, the larger the specification of the double-chamber shaft kiln is, the more economical the manufacturing cost is, and compared with a rotary kiln with the same specification, the manufacturing cost is also low, so that the application prospect is wide. However, the specification of the existing double-chamber shaft kiln can only be developed to 800t/d, and the following technical problems are urgently solved:

1) Along with the increase of the equivalent diameter, the geometric dimension (height, width or diameter) of the shaft kiln is inevitably increased according to a certain proportion, the deviation of hot air flow relative to the central part of the lower part of a roasting zone is increased, the hot air flow leaving the roasting zone of the roasting hearth is directly discharged into an annular channel of the hearth through the periphery in the descending process and then enters an annular channel of a heat storage hearth through a connecting channel of two hearths, so that high-temperature gas is far away from the central part of the lower part of the roasting zone in the downward flowing process, the hot air flow is deviated, the air flow density of the central part is low, the carried heat is less, the insufficient heat supply of the material at the part is caused to generate undercurning, and the deviation phenomenon is more obvious when the specification equivalent of the kiln is larger;

2) Along with the increase of the output scale, the shaft kiln is too large in the radius of a kiln chamber, when air flow for cooling materials from a heat storage kiln chamber cooling zone rises to enter the lower part of a kiln chamber roasting zone, the air flow is influenced by air flow distribution, hot air formed by heat exchange between cooling air and the materials mainly enters a middle area at the lower part of the roasting zone, and the temperature of the hot air is lower than the temperature of the materials, so that the materials are absorbed with heat to cause further under burning;

in order to compensate the defects caused by the overlarge radius of the kiln chamber, the height of a roasting zone is generally required to be additionally increased, so that the problems caused by the overlarge kiln body and the large flow resistance loss of high-temperature gas are solved, the power consumption of equipment is increased, and the construction cost of a project is also increased;

3) The problem of slow material decomposition of the double-hearth shaft kiln with low calorific value fuel exists:

roasting zone of roasting kiln: under the condition that low-calorific-value fuels such as coal gas and the like are not preheated, the combustion speed of the fuels is low, the average temperature of materials is low, the temperature difference between the temperature of waste gas and the temperature of the materials is small, the decomposition speed of the materials is low, the heat consumption is high, the amount of the waste gas is large, and the advantages of a roasting process are small;

roasting zone of the regenerative kiln chamber: the temperature difference between the waste gas temperature and the material temperature is almost not generated, the material is not decomposed, and the temperature of the material is increased by using part of fuel and increasing the heat consumption during the roasting after the cyclic rotation;

4) The spray gun safety cover snap-on current two thorax shaft kilns upper portion is on the kiln shell, and along with the increase of kiln thorax radius, the kiln body is increased, causes cantilever structure roof beam to increase the overlength, and the degree of difficulty that brings for the installation of cantilever type spray gun safety cover increases for the spray gun easily takes place slope or unstability scheduling problem.

SUMMERY OF THE UTILITY MODEL

For overcoming the prior art defect, the utility model provides a technical problem provides a two thorax shaft kilns of two-way calcination, through addding lower part center nozzle, make the fuel carry out the cocurrent flow calcination in the calcination kiln thorax, carry out the calcination in countercurrent at heat accumulation kiln thorax middle part, with the full cocurrent flow calcination mode of original two thorax shaft kilns, adjust to the two-way calcination mode of "cocurrent flow calcination + countercurrent roasting", can make the center of shaft kiln and peripheral heat distribution even, solve a great deal of problems such as the material is short of burning that arouses because of shaft kiln thorax radius is too big, improve product calcination quality, specially adapted 800t/d and above big specification two thorax shaft kilns, both for the two thorax shaft kilns maximization provides new technical approach, also for the two thorax shaft kilns development of low calorific value fuel provides new technical approach, with low nitrogen oxide, low calorific value cheap fuel, low heat loss, the obvious advantage fungible rotary kiln of low fly ash rate, wide development prospect has.

In order to achieve the purpose, the utility model adopts the following technical scheme:

a bidirectional roasting double-hearth shaft kiln comprises a rotary charging hopper, an opening and closing flashboard, a spray gun protection cover, a spray gun, a kiln hearth, a central nozzle, a discharging machine and a supporting frame, and is characterized in that the two kiln hearths are divided into a cooling zone, a roasting zone and a preheating zone from bottom to top and are symmetrically arranged on the supporting frame side by side, and the lower parts of the two kiln hearths are provided with annular channels and communicated through connecting channels; the rotary charging hopper and the opening and closing gate plate are arranged at the top of each kiln chamber; the central nozzle is arranged on a central hood at the bottom of each kiln chamber; the discharging machine is arranged at the bottom of each kiln chamber; the spray gun protection cover is arranged on the upper part of each kiln chamber, and a single or a plurality of spray guns are arranged inside the spray gun protection cover.

The spray gun safety cover is a plurality of, and length varies, and wherein the long spray gun safety cover one end welding of length is on the kiln shell of kiln thorax, and the other end sets up on the kiln shell of kiln thorax is used for supporting the support of fixed tripper with the hanging mode cantilever, and the short spray gun safety cover welding of length is on the kiln shell of kiln thorax, and the position that the spray gun stretches out in the spray gun safety cover is located the upper portion in kiln thorax roasting zone.

The central nozzle is positioned at the central position of the junction of the kiln chamber roasting zone and the cooling zone, and is internally provided with a plurality of layers of radial fuel nozzles, wherein 1 layer of the fuel nozzles can be arranged, and 2 layers of the fuel nozzles can also be arranged, namely 8230, and each layer of the fuel nozzles are arranged in a multipoint radial shape;

the shape of the spout can be round or rectangular.

Compared with the prior art, the beneficial effects of the utility model are that:

1) On the basis of the structure and roasting mode of the traditional double-hearth shaft kiln, a lower fuel central nozzle is added to realize up-and-down roasting and forward-and-backward parallel movement, namely the parallel-flow roasting of the double-hearth shaft kiln is adjusted to be a bidirectional roasting mode of parallel-flow roasting and countercurrent roasting, namely the roasting hearths adopt parallel-flow roasting, the heat storage hearths adopt countercurrent roasting, the parallel-flow roasting is taken as a main roasting mode, and the countercurrent roasting is taken as an auxiliary roasting mode, and the bidirectional roasting can improve the temperature of materials at the central part and the lower part of a roasting zone of the double-hearth shaft kiln so as to accelerate the parallel-flow roasting;

2) The central nozzle is used for supplementing fuel to the heat storage kiln chamber and supporting combustion by high-temperature cooling air, so that the overall temperature and the lower temperature of a roasting zone of the heat storage kiln chamber are improved, the parallel flow roasting speed of the next period is accelerated to complete roasting of materials, and the method is particularly suitable for a double-chamber shaft kiln of low-calorific-value fuel, and the problem of slow decomposition of the materials of the double-chamber shaft kiln of the low-calorific-value fuel is solved;

3) The central nozzle is used for supplementing fuel to the central part of the hearth of the heat storage kiln and high-temperature cooling air is used for supporting combustion, so that the temperature of the central area at the lower part of a roasting zone of the hearth of the heat storage kiln is increased, and the problems of excessive deviation of hot air flow at the central part and insufficient heat supply during parallel-flow roasting caused by overlarge radius of the hearth of the shaft kiln and insufficient material burning caused by the overlarge radius of the hearth are solved;

4) The spray gun protective cover is arranged at the upper part of the kiln chamber, one end of the spray gun protective cover is welded on the kiln shell, and the other end of the spray gun protective cover is arranged on a bracket which is arranged at the upper part of the shaft kiln and used for supporting the fixed distributor in a hanging mode in a cantilever manner, so that the problems that the traditional spray gun protective cover is difficult to install and is easy to incline or destabilize are solved;

5) The central nozzle is adopted, although part of coal gas is roasted by countercurrent, the heat consumption seems to be increased, the advantages of alternative heat exchange and cocurrent roasting of the double-hearth shaft kiln exist, the heat consumption is in a descending trend on the whole, and in addition, because the low-calorific-value coal gas is roasted alternately, the over-burning phenomenon cannot be generated during the countercurrent roasting;

6) The utility model discloses a two-way calcination double chamber shaft kiln technique, both be the new approach of two thorax lime shaft kiln macro-scale techniques, also be the new approach of low heat value fuel double chamber shaft kiln technique to the obvious advantage fungible rotary kiln of low nitrogen oxide, low heat value low price fuel, low heat loss, low fly ash rate has wide development prospect.

Drawings

Fig. 1 is a schematic view of the structure principle of the present invention;

fig. 2 isbase:Sub>A schematic view of the cross section A-A in fig. 1.

In the figure: 1-rotary charging hopper 2-opening and closing flashboard 3-spray gun protective cover 4-spray gun 5-kiln chamber 6-central nozzle 7-discharging machine 8-supporting frame

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings:

the two-way roasting double-chamber shaft kiln comprises a rotary charging hopper 1, an opening and closing flashboard 2, a spray gun protective cover 3, a spray gun 4, a kiln chamber 5, a central nozzle 6, a discharging machine 7 and a supporting frame 8, wherein the two kiln chambers 5 are divided into a cooling zone, a roasting zone and a preheating zone from bottom to top and are symmetrically arranged on the supporting frame 8 side by side, and the lower parts of the two kiln chambers 5 are provided with annular channels and communicated through connecting channels; the rotary charging hopper 1 and the opening and closing gate plate 2 are arranged at the top of each kiln chamber 5; the central nozzle 6 is arranged on a central hood at the bottom of each kiln chamber 5; the discharging machine 7 is arranged at the bottom of each kiln chamber 5; the spray gun protection cover 3 is arranged at the upper part of each kiln chamber 5, and a single or a plurality of spray guns 4 are arranged inside the spray gun protection cover.

The spray gun protection cover 3 is a plurality of, and length varies, and wherein the long 3 one end welding of spray gun protection cover of length is on the kiln shell of kiln thorax 5, and the other end sets up on the support that is used for supporting fixed tripper on 5 upper portions of kiln thorax with hanging mode cantilever, and the short 3 welding of spray gun protection cover of length is on the kiln shell of kiln thorax, and the position that spray gun 4 stretches out in the spray gun protection cover 3 is located the upper portion of 5 roasting zones of kiln thorax.

The central nozzle 6 is positioned at the central position of the junction of the roasting zone and the cooling zone of the kiln chamber 5, and is internally provided with a plurality of layers of radial fuel nozzles, wherein 1 layer of fuel nozzles can be arranged, and 2 layers of fuel nozzles can also be arranged, wherein 8230can be arranged;

the shape of the spout can be round or rectangular.

The roasting method comprises the following steps:

1) When the rotary kiln is in work, the central nozzle 6 and the spray gun 4 are operated by alternatively transforming and associating input of fuel or air, fuel or air is controlled to be conveyed to enable one of the two kiln chambers 5 to be a roasting kiln chamber (when the spray gun inputs fuel and the central nozzle inputs air) and the other one of the two kiln chambers to be a heat storage kiln chamber (when the spray gun inputs air and the central nozzle inputs fuel), the input fuel or air is switched at certain intervals, the roasting kiln chamber and the heat storage kiln chamber are alternatively transformed, namely, the alternative reversing of the functions of the roasting kiln chamber 5 and the heat storage kiln chamber is realized, and the block materials are sequentially preheated, roasted and cooled from top to bottom to finish the roasting process;

2) In a roasting kiln chamber, the opening and closing flashboard 2 is in a closed state, combustion-supporting air is fed into the kiln chamber 5 from an air inlet at the top of the kiln chamber 5, exchanges heat with materials in a preheating zone to obtain high temperature, then enters a roasting zone at the lower part, is mixed with fuel sprayed from a spray gun 4 to generate intense combustion and heat release to rapidly decompose the materials, the materials in the roasting kiln chamber move from top to bottom, and high-temperature waste gas flow generated by fuel combustion and the materials move from top to bottom in a cocurrent manner to carry out cocurrent roasting; the high-temperature waste gas flow enters the annular channel of the roasting kiln chamber all the way down and enters the heat storage kiln chamber through the connecting channel;

air is input into the central nozzle 6 of the roasting kiln chamber;

3) In a heat storage kiln chamber, the opening and closing flashboard 2 is in an opening state, the rotary charging hopper 1 charges materials in batches and distributes the materials into a preheating zone of the kiln chamber 5; the fuel sprayed from the lower central nozzle 6, high-temperature air from the material cooled below the central nozzle 6 and high-temperature waste gas from the roasting kiln chamber are mixed and combusted, the generated high-temperature waste gas flows upwards to enter a roasting zone of the heat storage kiln chamber and moves in a countercurrent manner with the material moving from top to bottom in the heat storage kiln chamber, and countercurrent roasting is carried out, so that the temperature of the material at the lower part of the heat storage kiln chamber is improved, the material which is not burnt is decomposed again, and meanwhile, the cocurrent flow roasting efficiency of the next period can be improved through countercurrent roasting; high-temperature waste gas enters a preheating zone at the upper part of the heat storage kiln chamber all the way upwards, and carries out a large amount of heat exchange with materials, the waste gas is discharged from the upper part of the kiln chamber 5 after being cooled to a lower temperature, and is discharged into the atmosphere through a smoke exhaust fan after being dedusted;

air is input into a spray gun 4 of the heat storage kiln chamber;

4) The roasting kiln chamber adopts automatic quick discharging, the heat storage kiln chamber adopts automatic slow discharging, so that the calcined product materials enter respective cooling zones and carry out countercurrent heat exchange with air from the bottoms of the two kiln chambers 5, and the fully cooled product materials are discharged by a discharging machine 7.

The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.

Claims (4)

1. A bidirectional roasting double-hearth shaft kiln comprises a rotary charging hopper, an opening and closing flashboard, a spray gun protection cover, a spray gun, a kiln hearth, a central nozzle, a discharging machine and a supporting frame, and is characterized in that the two kiln hearths are divided into a cooling zone, a roasting zone and a preheating zone from bottom to top and are symmetrically arranged on the supporting frame side by side, and the lower parts of the two kiln hearths are provided with annular channels and communicated through connecting channels; the rotary charging hopper and the opening and closing gate plate are arranged at the top of each kiln chamber; the central nozzle is arranged on a central hood at the bottom of each kiln chamber; the discharging machine is arranged at the bottom of each kiln chamber; the spray gun protection cover is arranged on the upper part of each kiln chamber, and a single or a plurality of spray guns are arranged inside the spray gun protection cover.

2. The shaft kiln with two chambers for bidirectional roasting of claim 1, wherein the number of the lance protection covers is several, and the length of the lance protection covers is different, wherein one end of the lance protection cover with long length is welded on the kiln shell of the kiln chamber, the other end of the lance protection cover with long length is arranged on the bracket of the upper part of the kiln chamber for supporting the fixed distributor in a hanging manner, and the lance protection cover with short length is welded on the kiln shell of the kiln chamber.

3. The bi-directional roasting double-hearth shaft kiln as claimed in claim 1, wherein the central nozzle is positioned at the central position of the junction of the roasting zone and the cooling zone of the kiln hearth, and is internally provided with 1 layer or 2 layers of \8230 \ 8230 \, each layer of fuel nozzles is arranged in a multi-point radial shape.

4. A bi-directional firing double-hearth shaft kiln as claimed in claim 3, wherein the shape of the ports is either circular or rectangular.

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