A local oxygen enrichment system for sleeve kiln

Abstract

The present invention discloses a local oxygen enrichment system for a sleeve kiln, comprising an oxygen production unit for producing pure oxygen; an ejector unit, whose inlet end is connected to the oxygen production unit; a heat exchange unit, whose inlet end is connected to the outlet end of the ejector unit, and the heat exchange unit is arranged on a hot gas pipeline from the outlet flue of the upper inner sleeve of the sleeve kiln to the heat exchanger; and an oxygen enrichment unit, whose inlet end is connected to the outlet end of the heat exchange unit, and the oxygen enrichment unit is arranged outside the combustion chamber, and the oxygen enrichment unit comprises an oxygen enrichment ring pipe, and the oxygen enrichment ring pipe is circumferentially provided with a plurality of oxygen enrichment spray guns and a plurality of oxygen enrichment nozzles, the oxygen enrichment spray guns are arranged at the combustion chamber panel, and the oxygen enrichment nozzles are arranged under the arch bridge. The present invention improves the combustion efficiency after local oxygen-enriched combustion, and the amount of combustion-supporting air volume and fuel used can be appropriately reduced, and a better energy-saving effect can be obtained. The fuel in an oxygen-enriched state can not only reduce the ignition temperature, but also accelerate the combustion speed, the combustion process is intense, the combustion reaction is sufficient and complete, and a better heat exchange effect is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of sleeve kilns, in particular to a local oxygenation system for a sleeve kiln. Background Art

[0002] Annular sleeve kiln is widely used in lime production enterprises in the fields of metallurgy, chemical industry and building materials, and has become a lime calcining technology with great attention. When the calorific value of the fuel is low, the intensity of the fuel combustion in the kiln is insufficient, and the quicklime will not be burned thoroughly. The low calorific value of the gas leads to a small proportion of combustible components and a large proportion of useless gases. Under the condition of unchanged energy consumption, the gas input and combustion-supporting air volume are both high, and the calcination zone is prone to extend to the preheating zone at the top of the kiln and the cooling zone at the bottom of the kiln. The large input of gas and combustion-supporting air leads to an increase in the amount of flue gas and a large amount of dust brought out, which affects the continuous and stable operation of the sleeve kiln and the control of equipment operation costs. At the same time, in order to solve the problem of ensuring the quality of quicklime when using low calorific value fuel, it is often necessary to increase the fuel supply. This causes the main problems encountered by the annular sleeve kiln in production to be large fuel consumption, low burnout rate, and high carbon monoxide (CO) content in the flue gas. This ultimately leads to an increase in the energy consumption of the sleeve kiln, while affecting the stability of the sleeve kiln production and the quality stability of the finished clinker.

[0003] Oxygen-enriched combustion uses oxygen-enriched air with a higher oxygen content than ordinary air to assist combustion. When fuel burns in oxygen-enriched air, the flame temperature increases significantly, the air intake and smoke exhaust required for combustion decrease, and unnecessary energy consumption is greatly reduced. The triatomic gas in the flue gas increases, which promotes the heat radiation transfer in the furnace. Oxygen-enriched combustion reduces the ignition temperature and burnout temperature of the fuel, strengthens the flame combustion speed, and improves the complete combustion efficiency of the fuel. Oxygen-enriched combustion is an important technology for energy saving and environmental protection. By controlling the oxygen concentration of the combustion-supporting air, the combustion characteristics, flame shape, and temperature are changed to ensure reasonable combustion.

[0004] However, the oxygen-enriched combustion currently used in sleeve kilns is overall oxygen-enriched combustion, which consumes a large amount of oxygen-enriched air, which can easily cause the overall combustion temperature of the sleeve kiln to be too high, resulting in overburning, and it is difficult to control the generation and emission of NOx. The low calorific value gas has a weak combustion intensity and a relatively low combustion temperature, which is not conducive to the normal decomposition of limestone in the kiln, and has a certain impact on the output of the sleeve kiln and the quality of the finished product. Increasing the fuel supply causes the annular sleeve kiln to consume a large amount of fuel, have a low burnout rate, and have a high carbon monoxide (CO) content in the flue gas. The low calorific value gas composition has a high content of non-combustible gas and a low content of combustible gas. The actual amount of air required increases, and after the gas is burned in the kiln, the amount of waste gas generated increases, and the heat loss of smoke exhaust increases. Overall oxygen-enriched combustion, with a large consumption of oxygen-enriched air, can easily cause the overall combustion temperature of the sleeve kiln to be too high, and it is difficult to control the generation and emission of NOx. Summary of the invention

[0005] The purpose of the present invention is to provide a local oxygen enrichment system for a sleeve kiln, which solves the problems of high fuel consumption, high carbon monoxide (CO) content in flue gas and low thermal efficiency when using low calorific value fuel, while also avoiding the problems of excessively high overall oxygen-enriched combustion temperature and large NOx generation. By adding an oxygen enriched air pipe, oxygen enriched air is allowed to participate in the combustion of sleeve kiln fuel, and oxygen enriched air with high oxygen content is used to partially replace the combustion-supporting gas. Less gas can be added during the combustion process, solving the problems of high low calorific value fuel consumption, increased flue gas volume and increased heat loss. At the same time, the combustion intensity of the fuel is improved, heat exchange is enhanced, and the generation and emission of NOx are controlled.

[0006] To achieve the above object, the present invention provides a local oxygenation system for a sleeve kiln, comprising:

[0007] Oxygen production unit, used to produce pure oxygen;

[0008] An ejector unit, the inlet end of which is connected to the oxygen production unit;

[0009] A heat exchange unit, the inlet end of which is connected to the outlet end of the ejector unit, and the heat exchange unit is arranged on the hot gas pipeline from the outlet flue of the upper inner sleeve of the sleeve kiln to the heat exchanger; and

[0010] An oxygen enrichment unit, whose inlet end is connected to the outlet end of the heat exchange unit, is arranged outside the combustion chamber, and includes an oxygen enrichment ring pipe. The oxygen enrichment ring pipe is circumferentially provided with a plurality of oxygen enrichment lances and a plurality of oxygen enrichment nozzles. The oxygen enrichment lances are arranged at the combustion chamber panel, and the oxygen enrichment nozzles are arranged under the arch bridge.

[0011] Furthermore, it also includes an air conditioning unit, which is connected to the inlet end of the ejection unit.

[0012] Furthermore, the injection unit is a pure oxygen-air injection mixer.

[0013] Furthermore, the heat exchange unit includes a heat exchange tube bundle.

[0014] Furthermore, the oxygen enrichment unit includes an upper combustion chamber oxygen enrichment unit and a lower combustion chamber oxygen enrichment unit, the inlet ends of the upper combustion chamber oxygen enrichment unit and the lower combustion chamber oxygen enrichment unit are respectively connected to the outlet end of the heat exchange unit, and the upper combustion chamber oxygen enrichment unit and the lower combustion chamber oxygen enrichment unit are respectively arranged outside the upper combustion chamber and the lower combustion chamber.

[0015] Furthermore, the number of the oxygen-enhancing lances and oxygen-enhancing nozzles corresponds one-to-one to the number of the combustion chambers.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The local oxygen-enriched combustion of the present invention improves the combustion efficiency, and the amount of combustion-supporting air and fuel used can be appropriately reduced, thereby achieving a better energy-saving effect. The fuel in the oxygen-enriched state can not only reduce the ignition temperature, but also accelerate the combustion speed, the combustion process is intense, the combustion reaction is sufficient and complete, and a better heat exchange effect is achieved.

[0018] (2) The present invention reduces the kiln top temperature. Since oxygen-enriched combustion is adopted, the combustion is relatively complete, the flame length is relatively shortened, and the temperature of the upper part of the flame is relatively low, thereby reducing the heat load on the kiln top.

[0019] (3) The local oxygen-enriched combustion-supporting method of the present invention greatly reduces oxygen consumption. The local oxygen-enriched combustion-supporting airflow cools the high-temperature area of ​​the flame and inhibits the formation of NOx in the local high temperature.

[0020] (4) The present invention adds an oxygen-enhancing ring pipe, an oxygen-enhancing nozzle and an oxygen-enhancing nozzle to a conventional sleeve kiln to achieve efficient combustion of locally oxygenated fuel, thereby reducing the air intake and flue gas emissions required for combustion and lowering the carbon monoxide (CO) content in the flue gas. At the same time, by utilizing local oxygenation, the combustion intensity is increased, heat exchange is enhanced, thermal efficiency is improved, and the generation and emission of NOx are controlled.

[0021] (5) The oxygen-enriching spray gun and the oxygen-enriching nozzle of the present invention extend into the combustion chamber panel to facilitate the selection of the best oxygen-enriching area and the organization of the flame shape, and to insulate all the oxygen-enriched air after the heat exchange tube bundle. Local oxygenation can improve the combustion of the sleeve kiln, reduce the CO content in the flue gas, reduce the flue gas emission, and reduce heat loss. The oxygen-enriched air participates in the combustion, which has obvious energy-saving and environmental protection effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the local oxygen enrichment system of the sleeve kiln of the present invention;

[0023] Figure 2 It is a structural schematic diagram of the oxygenation ring tube of the present invention;

[0024] Figure 3 It is a structural schematic diagram of the sleeve kiln of the present invention;

[0025] Figure 4 for Figure 3 A partial enlarged view of the middle A;

[0026] Figure 5 for Figure 3 A partial enlarged view of point B in the middle.

[0027] In the figure: 1. oxygen production unit; 2. air conditioning unit; 3. ejection unit; 4. heat exchange unit; 5. upper combustion chamber oxygenation unit; 6. lower combustion chamber oxygenation unit; 7. upper combustion chamber; 8. lower combustion chamber; 9. oxygenation ring pipe; 10. oxygenation spray gun; 11. oxygenation nozzle; 12. kiln body. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0030] Figures 1 to 5 The schematic diagram of the structure of the local oxygen enrichment system of the sleeve kiln of this embodiment is shown, which includes an oxygen production unit 1, an air conditioning unit 2, an ejection unit 3, a heat exchange unit 4 and an oxygen enrichment unit; wherein the oxygen production unit 1 is used to produce pure oxygen;

[0031] The air conditioning unit 2 is used to adjust the air flow entering the ejection unit 3;

[0032] The inlet end of the ejection unit 3 is connected to the oxygen production unit 1 and the air conditioning unit 2 respectively. The ejection unit 3 is a pure oxygen-air ejection mixer. The fresh air from the outside enters the pure oxygen-air ejection mixer as the ejected gas due to the ejection suction of the pure oxygen-air ejection mixer. The pure oxygen gas and the fresh air are mixed at a certain volume ratio. The oxygen content in the mixed gas is relatively high, which is called oxygen-enriched air.

[0033] The heat exchange unit 4, whose inlet end is connected to the outlet end of the pure oxygen-air ejector mixer, is a heat exchange tube bundle, which is arranged on the hot gas pipeline from the flue of the upper inner sleeve outlet of the sleeve kiln to the heat exchanger, and oxygen-enriched air flows through the heat exchange tube bundle, and its function is to use the heat of the flue gas on the hot gas pipeline to heat the oxygen-enriched air in the heat exchange tube bundle;

[0034] The oxygenation unit comprises an upper combustion chamber oxygenation unit 5 and a lower combustion chamber oxygenation unit 6, wherein the inlet ends of the upper combustion chamber oxygenation unit 5 and the lower combustion chamber oxygenation unit 6 are respectively connected to the outlet end of the heat exchange unit 4, and the upper combustion chamber oxygenation unit 5 and the lower combustion chamber oxygenation unit 6 are respectively arranged outside the upper combustion chamber 7 and the lower combustion chamber 8; the upper combustion chamber oxygenation unit 5 and the lower combustion chamber oxygenation unit 6 respectively have an oxygenation ring pipe 9, and the oxygenation ring pipe 9 is circumferentially provided with a plurality of oxygenation spray guns 10 and a plurality of oxygenation nozzles 11, wherein the oxygenation spray guns 10 are arranged at the combustion chamber panel, and the oxygenation nozzles 11 are arranged under the arch bridge.

[0035] In a preferred embodiment, the lengths of the oxygen-enhancing lance 10 and the oxygen-enhancing nozzle 11 extending into the combustion chamber panel are adjustable.

[0036] In a preferred embodiment, the number of oxygen-enriching lances 10 and oxygen-enriching nozzles 11 of the upper combustion chamber oxygen-enriching unit 5 corresponds one-to-one to the number of upper combustion chambers 7; the number of oxygen-enriching lances 10 and oxygen-enriching nozzles 11 of the lower combustion chamber oxygen-enriching unit 6 corresponds one-to-one to the number of lower combustion chambers 8.

[0037] A notable feature of the limestone calcining process in the sleeve kiln is that countercurrent calcination and parallel current calcination are carried out simultaneously. The two-layer combustion chamber distributed on the outer shell of the sleeve kiln divides the kiln body 12 into two countercurrent calcination zones and one parallel current calcination zone. The upper combustion chamber 7 is an incomplete combustion, and the supply of combustion-supporting air is insufficient, only about 50%. Under the action of the exhaust gas induced draft fan, the incompletely burned flue gas enters the upper material layer and meets the airflow containing excess air from below, so that the incomplete combustion products are completely burned. This area (from the upper combustion chamber 7 to the lower mouth plane of the upper inner sleeve) is the upper calcination zone. In this area, the direction of the air flow is opposite to the direction of material flow, and the calcination process is called countercurrent calcination. The combustion-supporting air required for fuel combustion in the lower combustion chamber 8 is excessive, which ensures a uniform calcination temperature. Part of the high-temperature flue gas generated by the combustion in the lower combustion chamber 8

[0038] It flows to the kiln top through the middle countercurrent calcination zone and the upper countercurrent calcination zone; the other part flows downward under the negative pressure suction generated by the high-speed airflow in the injection pipe, forming a parallel flow calcination zone between the lower combustion chamber 8 and the circulating gas inlet of the lower inner sleeve. The limestone is finally calcined in this area.

[0039] The present invention adds an oxygen-enhancing ring pipe, an oxygen-enhancing nozzle and an oxygen-enhancing nozzle to a conventional sleeve kiln to achieve efficient combustion of locally oxygenated fuel, reduce the air intake and flue gas emissions required for combustion, and reduce the content of carbon monoxide (CO) in the flue gas. At the same time, local oxygenation is utilized to increase combustion intensity, enhance heat exchange, improve thermal efficiency, and control the generation and emission of NOx.

[0040] The oxygen-enriching spray gun and the oxygen-enriching nozzle of the present invention extend into the combustion chamber panel to facilitate the selection of the best oxygen-enriching area and the organization of the flame shape, and to insulate all the oxygen-enriched air after the heat exchange tube bundle. Local oxygenation can improve the combustion of the sleeve kiln, reduce the CO content in the flue gas, reduce the flue gas emission, and reduce heat loss. The oxygen-enriched air participates in the combustion, which has obvious energy-saving and environmental protection effects.

[0041] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0042] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A local oxygenation system for a sleeve kiln, characterized in that: include: Oxygen production unit, used to produce pure oxygen; An ejector unit, the inlet end of which is connected to the oxygen production unit; A heat exchange unit, the inlet end of which is connected to the outlet end of the ejector unit, and the heat exchange unit is arranged on the hot gas pipeline from the outlet flue of the upper inner sleeve of the sleeve kiln to the heat exchanger; and An oxygen enrichment unit, whose inlet end is connected to the outlet end of the heat exchange unit, the oxygen enrichment unit is arranged outside the combustion chamber, the oxygen enrichment unit comprises an oxygen enrichment ring pipe, the oxygen enrichment ring pipe is circumferentially provided with a plurality of oxygen enrichment lances and a plurality of oxygen enrichment nozzles, the oxygen enrichment lances are arranged at the combustion chamber panel, and the oxygen enrichment nozzles are arranged under the arch bridge; The local oxygen enrichment system of the sleeve kiln also includes an air conditioning unit, which is connected to the inlet end of the ejection unit; The oxygen enrichment unit includes an upper combustion chamber oxygen enrichment unit and a lower combustion chamber oxygen enrichment unit, the inlet ends of the upper combustion chamber oxygen enrichment unit and the lower combustion chamber oxygen enrichment unit are respectively connected to the outlet end of the heat exchange unit, and the upper combustion chamber oxygen enrichment unit and the lower combustion chamber oxygen enrichment unit are respectively arranged outside the upper combustion chamber and the lower combustion chamber.

2. The system according to claim 1, characterized in that The ejection unit is a pure oxygen-air ejection mixer.

3. The system according to claim 1, characterized in that The heat exchange unit is a heat exchange tube bundle.

4. The system according to claim 1, characterized in that The number of the oxygen-enhancing lances and oxygen-enhancing nozzles corresponds one to one to the number of the combustion chambers.

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