Submerged arc furnace flue gas SCR urea pyrolysis denitration ammonia production device

Abstract

The utility model discloses a submerged arc furnace flue gas SCR urea pyrolysis denitration ammonia production device, relates to the technical field of urea pyrolysis denitration ammonia production, aims to solve the problem of high energy consumption of urea pyrolysis, and is characterized in that a deslagging service valve is mounted at the bottom of a pyrolysis furnace, and a urea solution injection system is connected to the top of the pyrolysis furnace; the top of one side of the pyrolyzing furnace is connected with a submerged arc furnace gas collecting hood through a gas collecting pipe, a submerged arc furnace is installed at the bottom of the submerged arc furnace gas collecting hood, a plurality of heat exchange tube bundles are installed at the bottom of the gas collecting pipe, the bottoms of the heat exchange tube bundles are connected through a gas distributing pipe, and the gas distributing pipe is connected with an induced draft fan. According to the utility model, indirect heat exchange is carried out by utilizing high-temperature flue gas and primary cold air in the submerged arc furnace, and a traditional heating mode of an electric heater is effectively replaced, so that the power consumption is obviously reduced; the whole process device is simple and practical, the investment can be effectively saved, the efficient denitration effect is achieved, and the application range is wide.

Description

Technical Field

[0001] The utility model relates to the technical field of urea thermal denitrification to produce ammonia, in particular to a submerged arc furnace flue gas SCR urea thermal denitrification to produce ammonia device. Background Art

[0002] SCR selective catalytic reduction denitrification technology generally uses liquid ammonia, ammonia water or urea as a reducing agent, and performs a denitrification catalytic reduction reaction under the action of a catalyst to remove nitrogen oxides NOx in flue gas. Among them, the production of ammonia using urea as a reducing agent is divided into urea thermal decomposition and urea hydrolysis. The principle of urea thermal decomposition reaction is as follows: CO(NH2)2→NH3+HNCO, HNCO+H2O→NH3+CO2.

[0003] The traditional urea pyrolysis process is to pump 50% urea solution to the furnace area metering and distribution module through a solution delivery pump, and then spray it into the pyrolysis furnace through a spray gun after metering and distribution; use primary cold air or hot air to heat to 550-600℃ through a high-power electric heater of about 500KW, and spray it into the pyrolysis furnace to pyrolyze urea to generate ammonia with a concentration of less than 5%, which is sprayed into the SCR reactor by the injection system for denitrification reaction. The traditional pyrolysis furnace structure is that the hot air from the electric heater is sprayed into the top, and the finished ammonia is discharged from the bottom, which is not convenient for slag discharge and maintenance. Utility Model Content

[0004] Aiming at the disadvantage of high energy consumption of common urea pyrolysis, combined with the large amount of waste heat generated in smelting production of various ore-heating furnaces such as electric arc furnaces and roasting furnaces, the utility model proposes a ore-heating furnace flue gas SCR urea pyrolysis denitrification and ammonia production device, which makes full use of the technical characteristics of common pyrolysis and hydrolysis SCR denitrification and various ore-heating furnace high-temperature flue gas, adopts indirect heat exchange to prepare heat source, and the overall device is simple and practical, with low investment cost, low operating cost, and high denitrification efficiency. It is particularly suitable for various ore-heating furnace flue gas urea pyrolysis denitrification with high-temperature waste heat heat source, and has a wide range of promotion and application prospects. It includes a slag discharge inspection valve installed at the bottom of the pyrolysis furnace, a urea solution injection system connected to the top of the pyrolysis furnace, a top of one side of the pyrolysis furnace is connected to an ore-heating furnace gas collecting hood through a gas collecting pipe, an ore-heating furnace is installed at the bottom of the ore-heating furnace gas collecting hood, and a plurality of heat exchange tube bundles are installed at the bottom of the gas collecting pipe. The bottoms of the heat exchange tube bundles are connected through gas distribution pipes, and the gas distribution pipes are connected to induced draft fans.

[0005] The utility model is further configured as follows: a denitration reactor port is reserved at the bottom of one side of the pyrolysis furnace.

[0006] The utility model is further configured as follows: the urea solution injection system comprises a metering distribution module, a pipeline valve group and an atomizing spray gun, and the metering distribution module is connected to the atomizing spray gun through the control of the pipeline valve group.

[0007] The beneficial technical effects of the utility model are as follows: the utility model utilizes the high-temperature flue gas and primary cold air inside the ore-fired furnace for indirect heat exchange, effectively replacing the traditional heating method of electric heaters, thereby significantly reducing power consumption; it is suitable for SCR urea pyrolysis to produce ammonia and denitrification treatment of flue gas from ore-fired furnaces such as electric arc furnaces, roasting furnaces, and glass kilns in industrial metallurgy and other industries; the entire process device is not only simple and practical, but also can effectively save investment and achieve efficient denitrification effect, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 The utility model process flow chart is shown.

[0009] Figure numerals: 1. Submerged arc furnace, 2. induced draft fan, 3. gas distribution pipe, 4. heat exchange tube bundle, 5. gas collecting pipe, 6. urea solution injection system, 7. pyrolysis furnace, 8. slag discharge inspection valve, 9. denitrification reactor port, 10. Submerged arc furnace gas collecting hood. DETAILED DESCRIPTION

[0010] Please refer to the attached Figure 1 Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0011] The utility model provides a submerged arc furnace flue gas SCR urea pyrolysis denitrification ammonia production device, comprising a pyrolysis furnace 7, which is designed as a normal pressure vertical cylinder shape, and a slag discharge inspection valve 8 is installed at the bottom of the pyrolysis furnace 7 for regular inspection and slag discharge. A urea solution injection system 6 is connected to the top of the pyrolysis furnace 7, and the urea solution injection system 6 is injected from the top of the pyrolysis furnace 7. The top of one side of the pyrolysis furnace 7 is connected to a mineral heating furnace gas collecting hood 10 through a gas collecting pipe 5. The diameter of the gas collecting pipe 5 is DN300-600mm. The bottom of the mineral heating furnace gas collecting hood 10 is installed with a mineral heating furnace 1. The hot air heat source is a hot air source of 550-650°C sprayed into the pyrolysis furnace 7 by the gas collecting pipe 5 at the top of one side of the pyrolysis furnace 7 for pyrolysis reaction. A plurality of heat exchange tube bundles 4 are installed at the bottom of the gas collecting pipe 5. 6-12 heat exchange tube bundles 4 with a diameter of DN50-100mm are selected and evenly distributed vertically. The bottoms of the heat exchange tube bundles 4 are connected through gas distribution pipes 3. 2-4 gas distribution pipes 3 with a diameter of DN300-600mm are selected and arranged horizontally on the inside of the mineral heating furnace gas collecting hood 10. The gas distribution pipes 3 are connected to the induced draft fan 2. The primary cold air is discharged into the gas distribution pipe 3 through the induced draft fan 2 and evenly flows into the heat exchange tube bundle 4. The hot flue gas above 1000°C generated during the smelting process of the submerged arc furnace 1 is indirectly heat exchanged with the cold air in the heat exchange tube bundle 4. The generated hot air is collected through the gas collecting pipe 5 and enters the pyrolysis furnace 7 for reaction. The primary heat exchange method is special, using the high-temperature flue gas inside the submerged arc furnace 1 and the primary cold air for indirect heat exchange, eliminating the traditional electric heater heating to save power consumption.

[0012] A denitration reactor port 9 is reserved at the bottom of one side of the pyrolysis furnace 7. The urea solution injection system 6 includes a metering distribution module, a pipeline valve group and an atomizing spray gun. The metering distribution module is connected to the atomizing spray gun through the pipeline valve group control. The 50% urea solution from the urea solution preparation area is pumped to the urea solution injection system 6 in the furnace area by a delivery pump. The solution is sprayed to the pyrolysis furnace 7 through an atomizing spray gun. The heat source is 550-600°C. The hot air is sprayed into the pyrolysis furnace 7 from the gas collecting pipe 5 to react with the urea solution for pyrolysis. The finished ammonia gas with a concentration below 5% is generated and enters the denitration reactor through the denitration reactor port 9 for denitration reaction.

[0013] According to the flow field simulation calculation of the flue gas temperature, hot air flow rate and other flow fields of the ore-fired furnace 1, the heat exchange area, pipe diameter and number are designed to ensure that the primary cold air is heat exchanged to 550-650°C to meet the pyrolysis reaction conditions. At the same time, the urea solution injection system 6 will adjust the concentration and flow of the urea solution through a chain adjustment mechanism according to the changes in the urea solution injection flow rate, pressure and nitrogen oxide concentration at the flue gas outlet, so as to optimize and save the amount of urea solution.

[0014] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0015] In the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0016] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0017] The term "comprise" or any other similar term is intended to cover a non-exclusive inclusion, such that a process, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article, or apparatus / device.

[0018] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A device for producing ammonia by pyrolysis of SCR urea from flue gas from a submerged arc furnace, comprising a pyrolysis furnace (7), characterized in that: A slag discharge inspection valve (8) is installed at the bottom of the pyrolysis furnace (7), a urea solution injection system (6) is connected to the top of the pyrolysis furnace (7), a top of one side of the pyrolysis furnace (7) is connected to a mineral heating furnace gas collecting hood (10) via a gas collecting pipe (5), a mineral heating furnace (1) is installed at the bottom of the mineral heating furnace gas collecting hood (10), a plurality of heat exchange tube bundles (4) are installed at the bottom of the gas collecting pipe (5), the bottoms of the heat exchange tube bundles (4) are connected via gas distribution pipes (3), and the gas distribution pipes (3) are connected to an induced draft fan (2).

2. The SCR urea thermal denitrification and ammonia production device for submerged arc furnace flue gas according to claim 1, characterized in that: A denitration reactor port (9) is reserved at the bottom of one side of the pyrolysis furnace (7).

3. The SCR urea thermal denitrification and ammonia production device for submerged arc furnace flue gas according to claim 1, characterized in that: The urea solution injection system (6) comprises a metering distribution module, a pipeline valve group and an atomizing spray gun, wherein the metering distribution module is connected to the atomizing spray gun through the control of the pipeline valve group.

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