An intelligent medium and high temperature SCR denitrification system

Abstract

The present invention relates to the technical field of intelligent denitration system, and provides an intelligent medium and high temperature SCR denitration system, including a reducing agent preparation system and a denitration reaction system, wherein the reducing agent preparation system includes a transport vehicle, the transport vehicle is connected to an ammonia delivery pipeline, and the other end of the ammonia delivery pipeline is connected to an ammonia unloading pump, and the other end of the ammonia unloading pump is connected to two ammonia water tanks through a first connecting pipe, the upper ends of the two ammonia water tanks are connected to the same spray water pipe, and the lower ends of the two ammonia water tanks are connected to the same second connecting pipe. The present invention overcomes the shortcomings of the prior art, has a reasonable design and a compact structure, solves the problem that the mixing of ammonia and flue gas in the existing SCR denitration process is not uniform, and the denitration effect is reduced. The present application adopts a variety of structural combinations, improves the mixing of ammonia and flue gas, better removes nitrogen oxides in flue gas, improves the efficiency of denitration, and has strong practicality.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent denitration systems, and in particular to an intelligent medium- and high-temperature SCR denitration system. Background Art

[0002] The principle of SCR (Selective Catalytic Reduction) denitrification is: under the action of the catalyst, the flue gas is mixed with ammonia, so that the nitrogen oxides in the flue gas are reduced to nitrogen and water.

[0003] As the concept of sustainable development gradually strengthens, the awareness of environmental protection is also increasing. In the process of industrial production, a lot of flue gas will be produced. These flue gases contain a lot of nitrogen oxides, including N2O, NO, NO2, N2O3, N2O4, N2O5, etc., but the main pollutants to the atmosphere are NO, NO2 and N2O. The nitrogen oxides produced in the combustion process are mainly NO and NO2 - collectively referred to as NOx, and a certain amount of N2O. In most combustion methods, NO accounts for more than 90%. Since NO will quickly oxidize to NO2 in the atmospheric environment, the mass concentration of NO2 is usually used to express the NOx concentration. Nitrogen oxides can cause the following hazards to the environment: causing acid rain or acid deposition; causing photochemical smog; N2O is a greenhouse gas, greenhouse effect and damage to the ozone layer, etc.

[0004] However, nitrogen oxides and ammonia are not mixed evenly under normal circumstances, resulting in an increase in the demand for ammonia, which not only increases costs but also fails to effectively improve the efficiency and effect of denitrification.

[0005] To this end, we propose an intelligent medium and high temperature SCR denitrification system. Summary of the invention

[0006] 1. Technical issues to be solved

[0007] In view of the deficiencies of the prior art, the present invention provides an intelligent medium and high temperature SCR denitrification system, which overcomes the deficiencies of the prior art, has a reasonable design and a compact structure, and solves the problem that the mixing of ammonia and flue gas in the existing SCR denitrification process is not uniform, thereby reducing the denitrification effect. The present application adopts a variety of structural combinations to improve the mixing of ammonia and flue gas, better remove nitrogen oxides in the flue gas, and improve the denitrification efficiency, and has strong practicality.

[0008] (II) Technical solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] An intelligent medium and high temperature SCR denitration system, comprising a reducing agent preparation system and a denitration reaction system, wherein the reducing agent preparation system comprises a delivery vehicle, wherein the delivery vehicle is connected to an ammonia delivery pipeline, and the other end of the ammonia delivery pipeline is connected to an ammonia unloading pump, and the other end of the ammonia unloading pump is connected to two ammonia water tanks through a first connecting pipe, the upper ends of the two ammonia water tanks are connected to the same spray water pipe, and the lower ends of the two ammonia water tanks are connected to the same second connecting pipe, the other end of the second connecting pipe is connected to the same ammonia water evaporator, and a plurality of parallel delivery pumps are arranged on the second connecting pipe, the other end of the ammonia water evaporator is connected to an ammonia-air mixer, the lower end of the ammonia-air mixer is connected to a dilution fan, the other end of the dilution fan is connected to an air inlet pipe, and the side wall of the ammonia-air mixer is connected to a denitration reaction system through a third connecting pipe;

[0011] The denitration reaction system includes a flue gas inlet, the other end of the flue gas inlet is through-connected with a heat exchanger, one side of the upper end of the heat exchanger is through-connected with a smoke and air duct, the other end of the smoke and air duct is through-connected with a denitration reactor, a third connecting pipe is inserted through the side wall of the smoke and air duct, a hot air furnace is arranged on the side wall of the smoke and air duct, the lower end of the denitration reactor is through-connected to the heat exchanger, one side of the lower end of the heat exchanger is through-connected with a main fan, and the air outlet of the main fan is through-connected with a purified gas exhaust pipe.

[0012] Furthermore, the third connecting pipe is located on a section inside the outer wall of the smoke and air duct and is sleeved with a reaction tank, the reaction tank is connected to the inner wall of the outer wall of the smoke and air duct through a bracket, a plurality of annular air ducts are provided on the reaction tank, the third connecting pipe is located on a section in the annular air duct and is rotatably connected to a rotating sleeve, and a plurality of blades are connected to the rotating sleeve, a plurality of through holes are provided on the rotating sleeve, and the blades are provided with air outlet holes that are mutually connected with the rotating sleeve.

[0013] Furthermore, two symmetrical fourth connecting tubes are connected through the side wall of the third connecting tube, and the side walls of the two fourth connecting tubes are connected through a fifth connecting tube, the fifth connecting tube passes through the side wall of the outer wall of the smoke and air duct and extends into the inner cavity of the outer wall of the smoke and air duct, and a plurality of air holes are provided on one end of the fifth connecting tube located in the inner cavity of the outer wall of the smoke and air duct, and an ammonia injection grid is sleeved on the fifth connecting tube, and the ammonia injection grid is connected to the inner wall of the outer wall of the smoke and air duct.

[0014] Furthermore, a nitrogen oxide detection device is provided on the purified gas exhaust pipe.

[0015] Furthermore, one end of the fourth connecting pipe located inside the third connecting pipe is connected to a baffle.

[0016] Furthermore, a rectifying grid is connected to the side wall of the outer wall of the smoke and air duct located above the third connecting pipe, and the rectifying grid is arranged parallel to the top wall of the outer wall of the smoke and air duct.

[0017] Furthermore, two combustion-supporting fans are connected in parallel to the air inlet of the hot blast stove.

[0018] Furthermore, the ammonia water tank and the ammonia water evaporator are both provided with liquid level gauges.

[0019] Furthermore, the denitration reactor is provided with a control panel, the control panel is provided with a display and control buttons, and the control panel has a built-in PLC controller.

[0020] (III) Beneficial effects

[0021] 1. The embodiment of the present invention provides an intelligent medium-high temperature SCR denitration system. It has the following beneficial effects:

[0022] 2. Through a simple combination of structural equipment, ammonia water can be quickly converted into ammonia gas, thereby improving the utilization efficiency of ammonia gas and further improving the denitrification effect.

[0023] 3. In order to improve the full mixing of ammonia and nitrogen oxides in the flue gas and improve the denitrification efficiency, a reaction tank is connected to the inner wall of the outer wall of the smoke duct, and a plurality of blades are rotatably connected to the third connecting pipe. The blades are provided with air outlets, so that ammonia is transported to the smoke duct through the air outlets. The smoke pushes the blades to rotate, and the centrifugal force accelerates the discharge speed of ammonia in the third connecting pipe, thereby improving the mixing of ammonia and flue gas. At the same time, as the blades rotate, the ammonia and flue gas are mixed more evenly, thereby improving the denitrification effect.

[0024] 4. In order to further improve the mixing of ammonia and flue gas, the third connecting pipe is connected to the fourth connecting pipe, the side wall of the fourth connecting pipe is connected to the fifth connecting pipe, the fifth connecting pipe extends to the inner cavity of the outer wall of the smoke and air duct, a plurality of air holes are opened on the fifth connecting pipe, and an ammonia spray grid is sleeved on the fifth connecting pipe. With the circulation of ammonia, ammonia is transported to the smoke and air duct again through the fourth connecting pipe and the fifth connecting pipe, and the ammonia is mixed with the flue gas again under the action of the ammonia spray grid, and the ammonia is mixed with the nitrogen oxides in the flue gas again to improve the denitrification efficiency.

[0025] 5. In order to make the ammonia and flue gas contact for a longer time and mix more evenly, a rectifying grid is connected to the side wall of the outer wall of the smoke and air duct above the third connecting pipe, and the rectifying grid is arranged parallel to the top wall of the outer wall of the smoke and air duct, which can make the airflow uniform and make the ammonia and flue gas contact for a longer time, thereby improving the denitrification effect.

[0026] 6. In order to facilitate control and improve intelligent effects, a control panel is provided on the denitrification reactor. The control panel is provided with a display and control buttons. The start and stop of multiple equipment such as the ammonia unloading pump, ammonia evaporator, and heat exchanger are controlled by the control buttons and display, thereby achieving intelligent control. The control panel has a built-in PLC controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the system structure of the present invention;

[0028] Figure 2 A schematic diagram of the structure of the reducing agent preparation system of the present invention;

[0029] Figure 3 A schematic diagram of the structure of the denitration reaction system of the present invention;

[0030] Figure 4 A partial cross-sectional schematic diagram of the smoke and air duct structure of the present invention;

[0031] Figure 5 The present invention Figure 4 Schematic diagram of the AA structure cross-section.

[0032] In the figure: reducing agent preparation system 1, conveying vehicle 11, ammonia unloading pump 12, first connecting pipe 13, ammonia water tank 14, spray water pipe 15, second connecting pipe 16, conveying pump 17, ammonia water evaporator 18, ammonia air mixer 19, third connecting pipe 110, dilution fan 111, denitration reaction system 2, flue gas inlet 21, heat exchanger 22, smoke and air duct 23, smoke and air duct outer wall 231, reaction tank 232, rotating sleeve 233, blades 234, fourth connecting pipe 235, fifth connecting pipe 236, ammonia spray grid 237, rectifying grid 238, denitration reactor 24, hot air stove 25, combustion-supporting fan 251, main fan 26. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0034] Refer to the attached Figure 1-5, an intelligent medium and high temperature SCR denitration system, including a reducing agent preparation system 1 and a denitration reaction system 2, the reducing agent preparation system 1 is mainly a process of preparing ammonia, the reducing agent preparation system 1 includes a delivery vehicle 11, the delivery vehicle 11 is connected to an ammonia delivery pipeline, and the other end of the ammonia delivery pipeline is connected to an ammonia unloading pump 12, the other end of the ammonia unloading pump 12 is connected to two ammonia water tanks 14 through a first connecting pipe 13, the two ammonia water tanks 14 are connected to one in use and one in reserve to reduce the occurrence of emergencies, the upper ends of the two ammonia water tanks 14 are connected to the same spray water pipe 15, which plays a certain protective role. When ammonia water leaks, it can be used to absorb ammonia, and the two ammonia water tanks The lower end of 14 is through-connected with the same second connecting pipe 16, and the other end of the second connecting pipe 16 is through-connected to the same ammonia evaporator 18. The ammonia is evaporated through the ammonia evaporator 18 to facilitate subsequent use. The second connecting pipe 16 is provided with a plurality of parallel delivery pumps 17, and the plurality of delivery pumps 17 also adopt a one-in-one standby mode. The other end of the ammonia evaporator 18 is through-connected with an ammonia-air mixer 19, and the lower end of the ammonia-air mixer 19 is through-connected with a dilution fan 111, and the other end of the dilution fan 111 is connected to an air inlet pipe. The ammonia is diluted again by the dilution fan 111, so that the ammonia reacts better with the nitrogen oxides in the flue gas, thereby improving the denitrification effect.

[0035] like Figure 3 As shown, the side wall of the ammonia-air mixer 19 is connected to a denitration reaction system 2 through a third connecting pipe 110. The denitration reaction system 2 includes a flue gas inlet 21. The other end of the flue gas inlet 21 is connected to a heat exchanger 22. The heat exchanger 22 adopts a GGH heat exchanger. The heat of the high-temperature flue gas at the denitration outlet is transferred to the imported low-temperature flue gas through the heat exchanger 22, thereby reducing energy consumption. A smoke duct 23 is connected to one side of the upper end of the heat exchanger 22. The other end of the smoke duct 23 is connected to a denitration reactor 24. The denitration reactor 24 is provided with multiple layers of catalysts. The flue gas is heated through the smoke duct 23. At the same time, the flue gas is heated in the flue gas. The air duct 23 can improve the mixing of flue gas and ammonia, and then improve the reaction effect under the action of the multi-layer catalyst in the denitrification reactor 24, thereby improving the denitrification efficiency. A third connecting pipe 110 is inserted through the side wall of the smoke and air duct 23, and a hot air furnace 25 is arranged on the side wall of the smoke and air duct 23, which can heat the flue gas in the smoke and air duct 23 to reach the reaction temperature. The lower end of the denitrification reactor 24 is connected to the heat exchanger 22, and a main fan 26 is connected to one side of the lower end of the heat exchanger 22. The main fan 26 provides a certain amount of power to facilitate the flow of flue gas, and the air outlet of the main fan 26 is connected to a purified gas exhaust pipe.

[0036] In this embodiment, Figure 4As shown, in order to improve the full mixing of ammonia and nitrogen oxides in the flue gas and improve the denitration efficiency, the third connecting pipe 110 is located in a section of the outer wall 231 of the smoke and air duct and is sleeved with a reaction tank 232, and the reaction tank 232 is connected to the inner wall of the outer wall 231 of the smoke and air duct through a bracket. A plurality of annular air ducts are opened on the reaction tank 232, and a section of the third connecting pipe 110 located in the annular air duct is rotatably connected to a rotating sleeve 233, and the rotating sleeve 233 is connected to a plurality of blades 234, and the rotating sleeve 232 is connected to the inner wall of the outer wall 231 of the smoke and air duct. A plurality of through holes are provided on the third connecting pipe 110, and an air outlet hole which is interpenetrating with the rotating sleeve 233 is provided on the blade 234, so that the ammonia in the third connecting pipe 110 is transported to the smoke duct 23 through the air outlet hole, and the smoke is moved under the push of the wind force of the main fan 26, and the smoke pushes the blade 234 to rotate, and the discharge speed of the ammonia in the third connecting pipe 110 is accelerated under the action of centrifugal force, thereby improving the mixing of ammonia and smoke. At the same time, as the blade 234 rotates, the ammonia and smoke are mixed more evenly, thereby improving the denitration effect.

[0037] In this embodiment, Figure 4 As shown, in order to further improve the mixing of ammonia and flue gas, two symmetrical fourth connecting pipes 235 are connected through the side wall of the third connecting pipe 110, and the side walls of the two fourth connecting pipes 235 are connected through the fifth connecting pipe 236, the fifth connecting pipe 236 passes through the side wall of the smoke and air duct outer wall 231 and extends to the inner cavity of the smoke and air duct outer wall 231, and the fifth connecting pipe 236 is located in the inner cavity of the smoke and air duct outer wall 231. A plurality of air holes are opened on one end of the fifth connecting pipe 236 located in the inner cavity of the smoke and air duct outer wall 231, and an ammonia spraying grid 237 is sleeved on the fifth connecting pipe 236, and the ammonia spraying grid 237 is connected to the inner wall of the smoke and air duct outer wall 231. With the circulation of ammonia, ammonia is transported to the smoke and air duct 23 again through the fourth connecting pipe 235 and the fifth connecting pipe 236, and the ammonia is mixed with the flue gas again under the action of the ammonia spraying grid 237, and the ammonia is mixed with the nitrogen oxides in the flue gas again, thereby improving the denitrification efficiency.

[0038] In this embodiment, in order to improve the emission standards, a nitrogen oxide detection device is provided on the purified gas exhaust pipe to ensure that the purified gas meets the emission standards.

[0039] In this embodiment, in order to facilitate the entry of ammonia into the fourth connecting pipe 235, a baffle is connected to one end of the fourth connecting pipe 235 located in the third connecting pipe 110. The baffle allows ammonia to better enter the fourth connecting pipe 235, thereby improving the mixing of ammonia and flue gas in the ammonia injection grid 237.

[0040] In this embodiment, Figure 4As shown, in order to make the ammonia gas contact with the flue gas for a longer time and mix more evenly, the side wall of the smoke and air duct outer wall 231 located above the third connecting pipe 110 is connected with a rectifying grid 238, and the rectifying grid 238 is arranged parallel to the top wall of the smoke and air duct outer wall 231, which can make the airflow uniform and make the ammonia gas contact with the flue gas for a longer time, thereby improving the denitrification effect.

[0041] In this embodiment, Figure 3 As shown, in order to improve the combustion efficiency of the hot blast stove 25, two combustion-supporting fans 251 are connected in parallel to the air inlet of the hot blast stove 25. The combustion efficiency of the hot blast stove 25 can be improved by using multiple combustion-supporting fans 251, thereby increasing the temperature of the flue gas more quickly and improving the subsequent denitrification efficiency.

[0042] In this embodiment, Figure 1 and 2 As shown, in order to conveniently check the amount of raw materials, the ammonia water tank 14 and the ammonia water evaporator 18 are both provided with liquid level gauges to observe the amount of raw materials and replenish them in time.

[0043] In this embodiment, in order to facilitate control and improve intelligent effects, a control panel is provided on the denitration reactor 24. A display and control buttons are provided on the control panel. The start and stop of multiple devices such as the ammonia unloading pump 12, the ammonia evaporator 18, and the heat exchanger 22 are controlled by the control buttons and the display, thereby achieving intelligent control. The control panel is built with a PLC controller, and the PLC controller adopts Siemens S7-400.

[0044] The electrical components mentioned in this article are all connected to an external main controller and 220V mains electricity, and the main controller can be a conventional known device for controlling a computer or the like.

[0045] 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 sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent medium and high temperature SCR denitration system, including a reducing agent preparation system and a denitration reaction system, Features: The reducing agent preparation system includes a transport vehicle, the transport vehicle is connected to an ammonia transport pipeline, and the other end of the ammonia transport pipeline is connected to an ammonia unloading pump, the other end of the ammonia unloading pump is connected to two ammonia water tanks through a first connecting pipe, the upper ends of the two ammonia water tanks are connected to the same spray water pipe, and the lower ends of the two ammonia water tanks are connected to the same second connecting pipe, the other end of the second connecting pipe is connected to the same ammonia water evaporator, a plurality of parallel transport pumps are arranged on the second connecting pipe, the other end of the ammonia water evaporator is connected to an ammonia-air mixer, the lower end of the ammonia-air mixer is connected to a dilution fan, the other end of the dilution fan is connected to an air inlet pipe, and the side wall of the ammonia-air mixer is connected to a denitration reaction system through a third connecting pipe; The denitration reaction system comprises a flue gas inlet, the other end of the flue gas inlet is connected to a heat exchanger, one side of the upper end of the heat exchanger is connected to a smoke duct, the other end of the smoke duct is connected to a denitration reactor, a third connecting pipe is inserted through the side wall of the smoke duct, a hot air furnace is arranged on the side wall of the smoke duct, the lower end of the denitration reactor is connected to the heat exchanger, one side of the lower end of the heat exchanger is connected to a main fan, and the air outlet of the main fan is connected to a purified gas discharge pipe; The third connecting pipe is located in a section of the outer wall of the smoke and air duct and is sleeved with a reaction tank, the reaction tank is connected to the inner wall of the outer wall of the smoke and air duct through a bracket, a plurality of annular air ducts are opened on the reaction tank, a section of the third connecting pipe is located in the annular air duct and is rotatably connected to a rotating sleeve, and a plurality of blades are connected to the rotating sleeve, a plurality of through holes are opened on the rotating sleeve, and air outlet holes that are mutually connected with the rotating sleeve are opened on the blades; Ammonia is transported to the smoke and air duct through the air outlet, and the smoke drives the blades to rotate, accelerating the discharge speed of ammonia in the third connecting pipe under the action of centrifugal force; Two combustion-supporting fans are connected in parallel to the air inlet of the hot blast stove.

2. An intelligent medium and high temperature SCR denitration system as claimed in claim 1, Features: Two symmetrical fourth connecting tubes are connected through the side wall of the third connecting tube, and the side walls of the two fourth connecting tubes are connected through a fifth connecting tube, the fifth connecting tube passes through the side wall of the outer wall of the smoke and air duct and extends into the inner cavity of the outer wall of the smoke and air duct, a plurality of air holes are provided on one end of the fifth connecting tube located in the inner cavity of the outer wall of the smoke and air duct, and an ammonia injection grid is sleeved on the fifth connecting tube, and the ammonia injection grid is connected to the inner wall of the outer wall of the smoke and air duct.

3. An intelligent medium and high temperature SCR denitration system as claimed in claim 1, Features: The purified gas exhaust pipe is provided with a nitrogen oxide detection device.

4. An intelligent medium and high temperature SCR denitration system as claimed in claim 2, Features: One end of the fourth connecting pipe located inside the third connecting pipe is connected with a baffle.

5. An intelligent medium and high temperature SCR denitration system as claimed in claim 1, Features: A rectifying grid is connected to the side wall of the outer wall of the smoke and air duct located above the third connecting pipe, and the rectifying grid is arranged parallel to the top wall of the outer wall of the smoke and air duct.

6. An intelligent medium and high temperature SCR denitration system as claimed in claim 1, Features: The ammonia water tank and the ammonia water evaporator are both provided with liquid level gauges.

7. An intelligent medium and high temperature SCR denitration system as claimed in claim 1, Features: The denitration reactor is provided with a control panel, the control panel is provided with a display and control buttons, and the control panel is provided with a built-in PLC controller.

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