Title of Invention

"A TOP-COMBUSTION HOT BLAST STOVE WITH A PRE-COMBUSTION CHAMBER HAVING A HEAT INSULATING LAYER"

Abstract

The present invention refers to a hot blast stove of blast furnace in the field of metallurgical industry, which aims to provide a top-combustion hot blast stove with its pre-combustion chamber having a heat insulating layer, which has long lifetime, By providing the heat insulating layer for the pre-combustion chamber, the heat transfer from the inner wall of the pre-combustion chamber to the inner walls of the coal gas ring cavity and the air ring cavity can be effectively blocked, so as to reduce the temperature of the inner walls of the coal gas ring cavity and the air ring cavity, and decrease the temperature stress and reduce the thermal expansion of the inner wall of the pre-combustion chamber, to achieve free sliding between the latter and the inner walls of the coal gas ring cavity and the air ring cavity. Pushing force against the inner wall of the coal gas ring cavity and the air ring cavity will not occur. The lifetime of which can be increased. Accordingly, a heat insulating layer of the ring cavity is provided in the second inner lining between the coal gas ring cavity and the air ring cavity. The inner wall of the pre-combustion chamber has a structure with a taper. A heat insulating lid is movable provided between the pre-combustion chamber and the vault (combustion chamber). It can enhance the effects of gas mixing and flow guiding and decrease the radiant heat for the pre-combustion chamber from the heat air flow when blowing the air flow, as required in different applications.

Full Text

Description A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer Field of the Invention The present invention refers to a hot blast stove for blast furnaces in the field of metallurgical industry. In particular, the present invention relates to a top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer Background of the Invention Hot blast with sufficient high temperature is required in the smelting process of a blast furnace. A hot blast stove is a generally used device for providing the hot blast. However, the top-combustion hot blast stove has a disadvantage that the partition wall of pre-combustion chamber is easily to be damaged because of frequent temperature oscillation. Although the top-combustion hot blast stoves used in the present industry have been improved on their structures which are considered having been made considerable progress over the early top-combustion hot blast stoves. For example, a relatively effective means for preventing the partition wall from being damaged by temperature stress is that the partition wall is divided into two individual parts, which shortens the length of the bricks of the wall and decreases the thermal expansion. However, there is still heat transfer as well as temperature gradient, as a result of which the lifetime of the hot blast stove is still not long enough. Further reducing the temperatures of the inner walls of the coal gas ring cavity and the air ring cavity, thereby decreasing the thermal expansion of the inner walls of the coal gas ring cavity the and air ring cavity, so as to minimizing the effects of temperature stress, becomes a main factor for increasing the lifetime of the hot blast stove. Summary of the Invention A primary object of the present invention is. to overcome the shortcomings found m the prior art and to provide a top-combustion hor blast stove with its pre-combustion chamber having a heat insulating layer, which has long lifetime, in order to achieve the above object, the technical solution employed in the present invention is that: A top-combustion hot blast stove with its pre-combustion chamber having a heat insulating layer comprises a pre-combustion chamber, a vault (combustion chamber) and a checker chamber, wherein the pre-combustion chamber has an inner cavity, a ring cavity and an inner lining; the ring cavity is divided into an upper ring cavity which acts as a coal gas ring cavity to be provided with coal gas, and a lower ring cavity which acts as an air ring cavity to be provided with air; the inner lining includes a first inner lining and a second inner lining; the first inner lining is provided between the inner cavity and the ring cavity; the second inner lining is provided between the upper ring cavity and the lower ring cavity; multi-rows of channels are provided on the first inner lining at places corresponding to the upper ring cavity and lower ring cavity respectively; and a heat insulating layer made of heat insulating material for the pre-combustion chamber is provided in the first lining. By providing the heat insulating layer for the pre-combustion chamber, the heat transfer from the inner wall of the pre-combustion chamber to the inner walls of the coal gas ring cavity and the air ring cavity can be effectively blocked, so as to reduce the temperature of the inner walls of the coal gas ring cavity and the air ring cavity, and decrease the temperature stress and reduce the thermal expansion of the inner wall of the pre-combustion chamber, to achieve free sliding between the latter and the inner walls of the coal gas ring cavity and the air ring cavity. Pushing force against the inner wall of the coal gas ring cavity and will not occur. Farther, the heat insulating layer made of insulating material for the ring cavity is also provided in the second inner lining between the coal gas ring cavity and the air ring cavity, so as to block the heat transfer between them. So, the thermal stress of the second inner lining can be effectively reduced when it is needed to provide the coal gas and the air by different preheating temperatures (such as high temperature air and low temperature coal gas), Further, the surface of the inner cavity of the pre-combustion chamber can be provided with a structure having a taper, for example, a positive taper or a reversed taper, according to the size of the furnace cavity, the distribution of air flow and the practical requirement for temperature, so as to enhance the effects of gas mixing and flow guiding in the pre-combustion chamber. Further, the top channels of multi-rows channels corresponding to lower ring cavity are provided with each central line of the top channels pointing to the central line of the pre-combustion chamber in a plane. By such arrangement, the high speed eddy of coal gas flow formed in the upper space inside the pre-combustion chamber is effectively blown through, so as to obtain the better effects of gas mixing and flow guiding. In addition, a movable heat insulating lid is provided between the pre-combustion chamber and the vault (combustion chamber). When blowing the air flow, the lid is located between the pre-combustion chamber and the vault (combustion chamber) to insulate the radiant heat of the heated air flow and reduce the temperature of the pre-combustion chamber. Thus, the latter and the thermal stress caused by it can be reduced. Further, the heat escaping is decreased in a certain degree. In combustion, the lid is located above the pre-combustion chamber, the mixing of coal gas and air will not be influenced. Generally, the present invention has the following useful, effects as the above structures are employed: 1. By providing the heat insulating layers for the pre-combustion. chamber and ring cavity, the heat transfer from the first inner lining to the second inner lining are effectively blocked, so as to reduce the thermal expansion and thermal stress of every parts of the pre-combustion chamber, to increase the lifetime of the hot blast stove. 2. As the effects of coal gas and air mixing and flow guiding in the pre-combustion chamber are enhanced, the combustion temperature and combustion efficiency are increased. 3. The radiant heat of hot blast for the pre-combustion chamber is reduced when the air flow is blown in. The thermal losses are decreased while the thermal vibration of the vault on the pre-combustion chamber is reduced. The present invention will be further described below with reference to the accompanying drawings and the preferred embodiments. Brief description of the drawings Fig.l is a view showing the basic structure of a single hot blast stove when the insulating lid is located between the pre-combustion chamber and the vault according to the embodiment of the present invention. Fig.2 is a view showing the basic structure of a single hot blast stove when the insulating lid is located above the pre-combustion chamber according to the embodiment of the present invention. Fig. 3 is an enlarged cross sectional view along direction A-A of Fig.1 Fig. 4 is an enlarged cross sectional view along direction E-Bofo Fig. Fig, 5 is an enlarged cross sectional view along direction C-C of Fig. I. Fig, 6 is an enlarged cross sectional view along direction D-D of Fig, 1 Fig.7 is a schematic diagram showing the temperature transfer from the surface of the inner wall of the pre-combustion chamber to the surface of the inner walls of the gas ring cavity and the air ring cavity according to the embodiment of the present invention. Fig.8 is a view showing the basic structure of a single hot blast stove having the inner surface of the pre-combustion chamber with the shape of a reversed taper according to the embodiment of the present invention. Fig.9 is a view showing the basic structure of a single hot blast stove without the insulating lid according to the embodiment of the present invention. In the drawings: 1. the cold air flow inlet 2. the grate and support 3. the checker brick 4. the checker chamber 5. the stove case 6. the stove lining 7. the heated air flow outlet 8. the vault (combustion chamber) 9. the supporting arm of the pre-combustion chamber 10. the air ring cavity 11. the air inlet 12. the upper wall of the air ring cavity 13. the insulating layer of the ring cavity 14.the lower wall of the gas ring cavity 15. the gas inlet 16. the gas ring cavity 17. the inner wall of the ring cavity 18. the heat insulating layer of the pre-combustion chamber [9. the inner wall of the pre-combustion chamber 20. the inner arch of the pre-combustion chamber 21 the inner lining of the pre-combustion chamber 22, the pre-combustion chamber 23.the insulating lids 24, the channels of the gas ring cavity 25, the first channel of the air ring cavity 26, the second channel of the air ring cavity 27, the pull-rod of the insulating lids 28. the smoke outlet 51. the thickness of the inner wall 19 of the pre-combustion chamber 52. the thickness of the heat insulating layer 18 of the pre-combustion chamber 53. the thickness of the inner wall 17 of the ring cavity Detailed description of the preferred embodiments As shown in Fig.l, Fig.2, they show separately the basic structure of a single hot blast stove when the insulating lid locates between the pre-combustion chamber and the vault and locates above the pre-combustion chamber according to the embodiment of the present invention. In which, the said top-combustion hot blast stove with its pre-combustion chamber having a heat insulating layer comprises a cold air flow inlet 1, a grate and a support 2, a smoke outlet 28, the checker brick 3 acting as heat accumulator, a checker chamber 4, a stove case 5, a stove lining 6, a heated air flow outlet 7, a vault (combustion chamber) 8, a supporting arm 9 of the pre-combustion chamber and a pre-combustion chamber 22 (the part restricted by the dash-dotted line). The said pre-combustion chamber 22 locates above the vault (the combustion chamber) 8 and is coaxial with the vault in the vertical direction. The pre-combustion chamber 22 comprises an air ring cavity 10, an air inlet 11, the upper wall 12 of the air ring cavity, the heat insulating layer 13 of the air ring cavity, the lower wall 14 of the coal gas ring cavity, a coal gas inlet 15, a coal gas ring cavity 16 the inner wall, of the nag cavity 1 /, the hear insulating layer 18 for the pre combustion chamber, the inner wail 19 of the pre-combustion chamber, the inner arch 20 of the pre-combustion chamber, the inner iining 21 of the.pre-combustion chamber, an insulating lid 23, a coal gas ring cavity 24, a first channel of the air rmg cavity 25, a second channel of the air ring cavity 26 and a pull-rod 27 of the insulating lid, In which, the inner wall 17 of the ring cavity, the heat insulating layer 18 for the pre-combustion chamber and the inner wall 19 of the pre-combustion chamber constitute the first inner lining; the upper wall 12 of the air ring cavity, the heat insulating layer 13 of the air ring cavity and the lower wall 14 of the coal gas ring cavity constitute the second inner lining. The inner sides of the case of the pre-combustion chamber 22 are provided with the coal gas ring cavity 16 and the air ring cavity 10 with the coal gas ring cavity 16 being above the air ring cavity 10. The coal gas ring cavity 16 is separated from the air ring cavity 10 by the upper wall of the air ring cavity 12, the heat insulating layer of the ring cavity 13 and the lower wall of the coal gas ring cavity 14. There are three layers of wall between the space of the coal gas ring cavity 16 and air ring cavity 10 and the space of the inner cavity of the pre-combustion chamber 22, i.e. the inner wall of the ring cavity 17, the heat insulating layer of the pre-combustion chamber 18 and inner wall 19 of the pre-combustion chamber. The channels 24 of the coal gas ring cavity, the first channel 25 of the air ring cavity and the second channels 26 of the air ring cavity are provided through the three layers of wall. The firebricks of the inner wall 19 of the pre-combustion chamber are set properly by way of expansion gap and sliding gap, thereby the inner wall 19 of the pre-combustion chamber 22 can neither displace radially under high temperature and nor push against the inner walls of the coal gas ring cavity and air ring cavity. Referring to Fig.4, the central line of each first channel is directed to the central line ot the precembustion chamber in a plane. Thus, when the gas pressure in the air inter n set, the speed of air ejected from each channel of the upper first channels by of the air nng cavity is maximal in the horizontal direction, so that the swirling coal gas flow with high speed formed in the upper space inside the pre-combustion chamber is effectively blown through to obtain the better effects of gas mixing and flow guiding than that in the prior art. Additionally, referring to Fig.5 and Fig.6, the central line of each channel 24 of coal gas ring cavity intersects the radial direction of pre-combustion chamber 22 at an angle fi in a plane, wherein, the angle formed by the central line of each channel of the lower coal gas ring cavity and the radius of the pre-combustion chamber in the horizontal plane is less than the angle formed by the central line of each channel of upper coal gas ring cavity and the radius of the pre-combustion chamber in the horizontal plane. The central line of each channel 26 of the second air ring cavity also intersects the radius direction of pre-combustion chamber 22 at an angle 6 in a plane (see Fig. 3). The angle and structure of which are the same as that of the prior art, and their detailed description is omitted here. The combination of the channel 24 of the coal gas ring cavity and the channel 26 of the second air ring cavity can cause the eddy with the sufficient gas mixing in the pre-combustion chamber 22, and make the gas flow guiding smoother and more stable. The head insulating layer 18, which is made of heat insulating materials and provided between the inner wall 19 of the pre-combustion chamber and the inner wall 17 of the ring cavity, blocks the heat transfer from the inner cavity of the pre-combustion chamber 22 to coal gas ring cavity 16 and air ring cavity 10, thereby the temperature of inner wall 17 of ring cavity is relatively lower so as to adapt to the periodical changes of the temperature during air flow blowing and combusting, decreasing the requirement on the thermal shock ot the firebricks and reducing the temperature stress of the inner wall 17 of the ring cavity. Meanwhile, by shortening the firebricks of the inner wall 19 of the pre-combustion chamber, accordingly, the amount of thermal expansion is decreased, which effects to reduce the thrust against the inner wall 17 of the ring cavity. The insulating part between coal gas ring cavity 16 and air ring cavity 10 consist of the lower wall 14 of the coal gas ring cavity, heat insulating layer 13 and the upper wall 12 of the air ring cavity, so as to block the heat transfer of the air from coal gas ring cavity 16 to air ring cavity 10. After the coal gas and air are preheated, and the temperature difference is large, it can prevent effectively the firebricks of the insulating layer of the coal gas ring cavity 16 and air ring cavity 10 from being deformed and damaged by the thermal stress, which is caused by the larger temperature difference between the upper surface and lower surface thereof. A insulating lid 23 is movable provided between the vault (combustion chamber) 8 and the pre-combustion chamber 22. When blowing air flow, the insulating lid is in the lower limit place (see Fig.l) to insulate the radiant heat of heated air and reduce the temperature in the inner cavity of the pre-combustion chamber 22. In combustion, the insulating lid is located in the upper limit place (see Fig.2) so as not to affect the combustion of gas mixture. The material of the heat insulating layer 18 of the pre-combustion chamber and the heat insulating layer 13 of the ring cavity is light-weight brick with low thermal conductivity or fire resisting fibre board made from silicic acid aluminum. Fig.7 shows that the temperature decline from the inner wall 19 of the pre-combustion chamber to the inner wall 17 of the ring cavity because of the low thermal conductivity of the heat insulating layer 18 of the pre-combustion chamber. In which, 81 represents the thickness of inner wall 19 or the pre-combustion chamber 82 pepresents the thickness of the heat insulating layer 18 of the pre-combustion chamber, 53 represents the thickness of the inner wall 17 of the ring cavity. As seen from the graph of temperature distribution, the provision of the heat insulating layer 18 of the pre-combustion chamber may significantly reduce the temperature of the inner wall 17 of the ring cavity. The inner surface of the pre-combustion chamber 22 can be provided with a structure having a taper, The heat insulating layer 18 of the pre-combustion chamber and the inner surface of the inner wall 19 of the pre-combustion chamber are generally parallel. The inner surface of the pre-combustion chamber can be provided with a structure having a positive taper (as shown in Fig.l and Fig.9) or a reversed taper (as shown in Fig.8), according to the size of the furnace cavity, the distribution of air flow and the practical requirement for temperature, so as to enhance the effects of gas mixing and flow guiding. The ratio of the total cross section area of the channels 25, 26 of the air ring cavity to the total cross section area of the channels 24 of the coal gas ring cavity is generally the same as the ratio of air to fuel, to ensure the velocity of coal gas flow from the outlet of the channels 24of the coal gas ring cavity is the same as the velocity of air flow from the outlet of the channels 25, 26 of the air ring cavity. So, it conduces not only to the mixing of the coal gas and the air in the pre-combustion chamber, but also simplifies the structure of the gas supplying devices individually connected to the inlet of the air and the inlet of the coal gas. Based on the practical requirements for manufacture and application, the above insulating lid 23 can be removed from the hot blast stove of the present invention, in order to simplify the manufacture and operation on the hot blast stove. We claim: i. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer, comprising a pre-combustion chamber a vault and a checker chamber, wherein the pre-combustion chamber has an inner cavity, a ring cavity and inner linings; the ring cavity is divided into upper ring cavity and lower ring cavity serving respectively as a coal gas ring cavity for supplying coal gas and an air ring cavity for supplying air; the inner linings include a first inner lining and a second inner lining, the first inner lining is provided between the inner cavity and ring cavity, the second inner lining is provided between the upper ring cavity and lower ring cavity; multi-rows of channels are provided on the first inner lining at places respectively corresponding to the upper ring cavity and lower ring cavity, characterized in that a heat insulating layer made of heat insulating material for the pre-combustion chamber is provided in the first lining. 2. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1, characterized in that the surface of the inner cavity has a taper. 3. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that the heat insulating layer of the pre-combustion chamber and the surface of the inner cavity are parallel. 4. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that the ratio of the total cross section area of the channels of coal gas ring cavity to the total cross section area of the air ring cavity is the same as the ratio of air to fuel. 5. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that a upward and downward movable insulating lid is provided between the pre-combustion chamber and the vault. 6. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that a heat insulating layer of the ring cavity made from insulating material is provided in the second inner lining. 7. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that each central line of the top channels of the multi-rows of channels corresponding to lower ring cavity is directed horizontally to the central line of the pre-combustion chamber. 8. A top-combustion hot blast stove with a pre-combustion chamber having a heat insulating layer according to claim 1 or 2, characterized in that the angle formed between the central line of each channel of the lower ring cavity and the radius of the pre-combustion chamber in the horizontal plane is less than the angle formed between the central line of each channel of the upper ring cavity and the radius of the pre-combustion chamber in the horizontal plane in the multi-rows of channels corresponding to the upper ring cavity. 9. A top-combustion hot blast stove substantially as herein described with reference to accompanying drawings.

Documents:

1672-del-2005-1672-del-2005-Drawings.pdf

1672-del-2005-Abstract-(28-08-2012).pdf

1672-del-2005-abstract.pdf

1672-del-2005-claims.pdf

1672-del-2005-Correspondence Others-(09-10-2014).pdf

1672-del-2005-Correspondence Others-(10-04-2012).pdf

1672-DEL-2005-Correspondence Others-(11-01-2012).pdf

1672-del-2005-Correspondence Others-(28-08-2012).pdf

1672-DEL-2005-Correspondence-Others-(13-05-2010).pdf

1672-del-2005-correspondence-others.pdf

1672-del-2005-description (complete).pdf

1672-del-2005-drawings.pdf

1672-del-2005-Form-1-(28-08-2012).pdf

1672-del-2005-form-1.pdf

1672-del-2005-form-18.pdf

1672-del-2005-Form-2-(28-08-2012).pdf

1672-del-2005-form-2.pdf

1672-del-2005-form-26.pdf

1672-del-2005-Form-3-(09-10-2014).pdf

1672-del-2005-Form-3-(28-08-2012).pdf

1672-del-2005-form-3.pdf

1672-del-2005-Form-5-(28-08-2012).pdf

1672-del-2005-form-5.pdf

1672-del-2005-GPA-(09-10-2014).pdf

1672-del-2005-GPA-(10-04-2012).pdf

1672-del-2005-Petition-137-(28-08-2012).pdf