CN109432983B - Nitrogen oxide-containing tail gas treatment system - Google Patents
Nitrogen oxide-containing tail gas treatment system Download PDFInfo
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- CN109432983B CN109432983B CN201811464106.1A CN201811464106A CN109432983B CN 109432983 B CN109432983 B CN 109432983B CN 201811464106 A CN201811464106 A CN 201811464106A CN 109432983 B CN109432983 B CN 109432983B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/75—Multi-step processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/46—Removing components of defined structure
- B01D53/54—Nitrogen compounds
- B01D53/56—Nitrogen oxides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/77—Liquid phase processes
- B01D53/78—Liquid phase processes with gas-liquid contact
Abstract
The invention discloses a nitrogen oxide-containing tail gas treatment system which has the advantages of high absorption efficiency, standard treatment, highest absorption efficiency of 99.5 percent and nitrogen oxide emission concentration of less than or equal to 200mg/m3The investment and operation cost is low, the integration level is high, and the operation flexibility is large; each absorption treatment unit of the device is an independent mechanism, and can be operated and controlled independently, so that the tail gas at the outlet can be ensured to reach the standard and be discharged under the most economic condition; the maintenance and adjustment do not need the shutdown of the whole system, so that the continuity of the absorption treatment can be ensured; the absorption liquid with high solute content can be used for treating the waste gas with higher concentration, the absorption liquid with low solute content is used for treating the waste gas with lower concentration, the discharged waste gas is ensured to be better purified, and the waste of the absorption liquid and the subsequent treatment cost can be avoided by discharging the absorption liquid with high solute content; the automatic replacement of water between the water tanks is realized by adopting the ball float valve and the siphon, the device is simple and practical, and the failure rate is lower.
Description
Technical Field
The invention relates to a waste gas treatment system, in particular to a nitrogen oxide-containing tail gas treatment system.
Background
The nitrogen oxide-containing tail gas contains nitrogen monoxide, nitrogen dioxide, laughing gas, dinitrogen pentoxide and the like which are common atmospheric pollutants, and the main components of the nitrogen oxide-containing tail gas are nitrogen monoxide and nitrogen dioxide.
The nitrogen oxides are treated by a reduction method, a plasma activation method, a biochemical method, an adsorption method, a liquid absorption method, or the like. The liquid absorption method is a method of purifying exhaust gas by absorbing nitrogen oxides in the exhaust gas with water or an aqueous solution of an acid, an alkali, or a salt. However, the commonly adopted single-stage spray water absorption method or single-stage spray alkali-adding absorption method has the main disadvantages of low technical level, low purification efficiency, poor purification effect and substandard waste gas treatment.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a nitrogen oxide-containing tail gas treatment system.
In order to achieve the purpose, the invention adopts the technical scheme that: a nitrogen oxide-containing tail gas treatment system comprises a first spray tower, a second spray tower, a third spray tower, a fourth spray tower and a fifth spray tower, wherein the first spray tower, the second spray tower, the third spray tower, the fourth spray tower and the fifth spray tower respectively comprise at least two packing layers, a gas inlet is formed in the bottom of the first spray tower, the top of the first spray tower is communicated with the side wall of the top of the second spray tower through a sealing pipeline, the bottom of the second spray tower is communicated with the bottom of the third spray tower through a sealing pipeline, the top of the third spray tower is communicated with the side wall of the top of the fourth spray tower through a sealing pipeline, and the bottom of the fourth spray tower is communicated with the bottom of the fifth spray tower through a sealing pipeline; the first spray tower, the second spray tower, the third spray tower, the fourth spray tower and the fifth spray tower are respectively connected with a first water tank, a second water tank, a third water tank, a fourth water tank and a fifth water tank through water pumps; the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank are all filled with spraying liquid; the spraying liquid in the first water tank and the second water tank is water; the spraying liquid in the third water tank and the fourth water tank is alkaline solution; the spray liquid in the fifth water tank is oxidant solution;
at least one of the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank is a multi-stage water tank, the stage number of the multi-stage water tank is n stages, n is more than or equal to 2, the n stages of water tanks are sequentially overlapped from top to bottom, the second stage water tank is positioned below the first stage water tank, the nth stage water tank is positioned at the bottom, a water replenishing port is arranged on the first stage water tank, a water outlet is arranged on the nth stage water tank, and the water replenishing port is communicated with each stage of water tank through a water replenishing ball float valve; the upper and lower adjacent two-stage water tanks are communicated through a siphon pipe, the upper end siphon pipe positioned in the upper layer water tank is provided with a water inlet, the lower end siphon pipe wall positioned in the lower layer water tank is provided with a water outlet, the other water tanks except the nth stage water tank are respectively provided with a siphon ball float valve, the siphon ball float valve controls the opening and closing of the water outlet on the lower end siphon pipe wall, when the water level is lowered to the lowest set position, the siphon ball float valve controls the water outlet to be opened, and when the water level is raised to the highest set position, the siphon ball float valve;
the spray tower connected with the multi-stage water tanks is a multi-stage spray tower, the multi-stage spray tower is provided with N stages of purification equipment which are sequentially arranged from top to bottom, N is more than or equal to 2, the second stage of purification equipment is positioned below the first stage of purification equipment, the Nth stage of purification equipment is positioned at the lowest part, the first stage of purification equipment is positioned at the highest part, the purification equipment comprises a spray component, a packing layer and liquid collecting tanks for collecting absorption liquid are sequentially fixed below the spray component, and the bottom of each liquid collecting tank is respectively connected with one stage of water tanks in the multi-stage water tanks through liquid discharge pipes; and each stage of water tank is provided with a liquid inlet and a liquid outlet, the liquid inlets on the two adjacent layers of water tanks are respectively communicated with a liquid discharge pipe at the bottom of the liquid collecting tank on the two adjacent layers of purifying equipment, and the liquid outlets on the two adjacent layers of water tanks are respectively communicated with the spraying components on the two adjacent layers of purifying equipment.
The treatment principle in each stage of spray tower is as follows:
1) treatment in the first spray tower: dissolving water-soluble components in nitrogen oxide in water to produce nitric acid
Reaction equation 1: 3NO2+H2O＝2HNO3+NO
Reaction equation 2: the oxygen in the air reacts with NO to convert into NO which is easily soluble in water2：2NO+O2＝2NO2
2) Treatment in the second spray tower: continuously dissolving the water-soluble components in the nitrogen oxide in water to generate nitric acid
Reaction equation 1: 3NO2+H2O＝2HNO3+NO
Reaction equation 2: the oxygen in the air reacts with NO to convert into NO which is easily soluble in water2：2NO+O2＝2NO2
3) Treatment in the third spray tower: residual NO2Through an alkali liquor absorption reaction partTheory of things
The reaction equation is as follows:
2NO2+2NaOH＝NaNO2+NaNO3+H2O
3NO2+H2O＝2HNO3+NO
HNO3+NaOH＝NaNO3+H2O
4) treatment in the fourth spray tower: residual NO2By treatment with alkali liquor absorption reaction
The reaction equation is as follows:
2NO2+2NaOH＝NaNO2+NaNO3+H2O
3NO2+H2O＝2HNO3+NO
HNO3+NaOH＝NaNO3+H2O
5) final strengthening treatment in the fifth spray tower
And (3) spraying and absorbing by using an oxidant solution, wherein the oxidant is at least one of sodium perchlorate, sodium chlorate, sodium chlorite, sodium percarbonate and sodium persulfate.
The nitrogen oxide-containing tail gas treatment system firstly adopts water for spraying absorption treatment, then adopts alkali liquor for spraying absorption treatment, and finally adopts oxidant solution for spraying absorption treatment, and adopts a five-stage spraying absorption tower, so that the highest absorption efficiency can reach 99.5%, and the emission concentration of nitrogen oxide is less than or equal to 200mg/m3And the running cost is low.
The absorption liquid which absorbs the waste gas is stored in a water tank, and the absorption liquid in the water tank flows into the water tank through a liquid discharge pipe; the absorption liquid in the water tank flows into the spraying assembly through the liquid inlet pump and the liquid inlet pipe. When the top discharge gas is monitored to reach a set value or the preset time is reached, a drain valve of a bottom water tank (nth-stage water tank) is opened to discharge saturated absorption liquid; the drainage process of the water tank specifically comprises the following steps: when the top discharge gas reaches a set value or a preset time is monitored, a drain valve of the nth-stage water tank is opened to drain saturated absorption liquid, when the water level is lowered to a lowest set position (which can be a position where the absorption liquid is drained completely), a siphon floating ball valve controls a water outlet on a siphon pipe in the nth-stage water tank to be opened, water in the nth-1-stage water tank flows out from the water outlet in the nth-stage water tank through the siphon pipe, the water level in the nth-stage water tank rises, the water level in the nth-1-stage water tank simultaneously falls, and when the water level in the nth-stage water tank rises to a highest set position, the siphon floating ball valve controls the water outlet to be closed, water in the nth-1-stage water tank stops flowing in, and displacement of the water from the nth-stage water tank to the nth-stage water tank is completed. Similarly, when the water level in the (n-1) th-stage water tank is lowered to the lowest set position, the displacement from the (n-2) th-stage water tank to the (n-1) th-stage water tank is realized by water through a siphon pipe and a siphon ball float valve, and when the water level in the first-stage water tank is lower than the set position, the water supplementing ball float valve is opened to supplement new absorption liquid to the first-stage water tank, so that the displacement progressive water change of the whole water tank is realized. The automatic replacement of water between the water tanks is realized by adopting universal accessories such as the ball float valve and the siphon, the automatic replacement is simple and practical, and compared with an electric valve, a pneumatic valve, a water pump and the like which have high failure rate and short service life when treating corrosive liquid, the failure rate is lower.
Therefore, the absorption liquid with high solute content is used for treating the waste gas with higher concentration, the absorption liquid with low solute content is used for treating the waste gas with lower concentration, the discharged waste gas is ensured to be better purified, and the waste of the absorption liquid and the subsequent treatment cost can be avoided by discharging the absorption liquid with high solute content.
The specific setting stages of the water tank and the purification device can be set according to specific conditions according to factors such as the concentration of the waste gas and the treatment efficiency of the spray liquid. Each stage of water tank can adopt the arrangement of multi-stage water tanks, the first spray tower, the third spray tower and the fifth spray tower are counter-flow spray towers, the second spray tower and the fourth spray tower are downstream spray towers, the connection mode with the multi-stage water tanks can be adopted, one or more water tanks can be arranged by the multi-stage water tanks, and the specific situation can be determined according to actual requirements.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, an air inlet of the first spray tower is connected with an air outlet of a buffer tank, and an air inlet and a nitrogen oxide inlet are arranged on the buffer tank.
In the buffer tank, air and nitrogenThe oxide is mixed with air according to the proportion of concentration, and the oxygen in the air can be converted into NO which is easily dissolved in water by NO in the nitrogen oxide2Composition, reaction equation: 2NO + O2＝2NO2. According to the inorganic substance technology (Maling edition, P34), when the temperature is lower than 100 ℃ under normal pressure or the temperature is lower than 200 ℃ under 0.8Mpa, the oxidation rate of NO is almost 100%, and the reaction rate of NO oxidation is reduced along with the temperature increase and increased along with the pressure increase, so that the NO can be mixed with air by keeping the temperature in the buffer tank low, and the NO is converted into NO which is easily dissolved in water2。
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, a liquid discharge end of the upper-layer water tank is connected with a spraying assembly of the upper-layer purification equipment through a liquid inlet pipe, a valve and a liquid inlet pump, and a liquid discharge end of the lower-layer water tank is connected with the spraying assembly of the lower-layer purification equipment through the liquid inlet pipe, the valve and the liquid inlet pump. The arrangement of the graded absorption is more favorable for increasing the absorption efficiency when reverse spraying is adopted.
In a preferred embodiment of the nitrogen oxide-containing tail gas treatment system according to the present invention, the liquid collection tank is provided with a gas inlet of a gas permeable tube for allowing gas to pass through, and an upper port of the gas permeable tube is positioned higher than a bottom of the liquid collection tank.
As a preferred embodiment of the nitrogen oxide-containing exhaust gas treatment system of the present invention, an opening is formed in the top of the liquid collecting tank, the side wall of the liquid collecting tank is tightly attached to the inner wall of the spray tower, and a water blocking cap is disposed above the upper port of the gas permeable pipe and blocks liquid from flowing into the gas permeable pipe.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system of the present invention, the siphon float valve is sleeved on the lower end siphon tube, the siphon float valve can move up and down along the lower end siphon tube, the water outlet is arranged on the tube wall of the lower end siphon tube, and the relative movement between the siphon float valve and the siphon tube is used to control the opening and closing of the water outlet.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, the siphon float valve is connected with the control float ball through a float ball connecting rod, the other end of the control float ball is fixedly arranged on the top wall, the siphon float valve is provided with a vertical chute, the float ball connecting rod can move up and down relatively along the chute, the siphon float valve can descend along with the descending of the water level, the control float ball controls the siphon float valve not to move relative to the siphon pipe through the float ball connecting rod before the water level rises to the highest set position, and when the water level rises to the highest set position, the control float ball drives the siphon float valve to move upwards through the float ball connecting rod to control the closing of the water outlet.
When the water level descends, the siphon ball float valve descends along with the descending of the water level along the siphon pipe at the lower end, the floating ball connecting rod moves downwards along the vertical sliding groove, when the water level descends to the lowest set position, the siphon ball float valve controls the water outlet on the siphon pipe at the lower end to be opened, the water level ascends, and before the water level ascends to the highest set position, the control floating ball controls the siphon ball float valve not to move relative to the siphon pipe through the floating ball connecting rod, so that the water outlet is in an open state before the water level ascends to the highest set position, and when the water level ascends to the highest set position, the control floating ball drives the siphon ball float valve.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system of the present invention, the spray tower is provided with a viewing port corresponding to the position of each of the purification devices.
In a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, a floating part is fixedly arranged at the bottom of the siphon float valve. The floating piece has the function of making the siphon ball float valve have certain buoyancy and descend along with the descending of the water level.
In a preferred embodiment of the nitrogen oxide-containing tail gas treatment system of the present invention, the oxidant solution is at least one of sodium perchlorate, sodium chlorate, sodium chlorite, sodium percarbonate and sodium persulfate; the alkali solution is sodium hydroxide solution.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, an air outlet at the top of the fifth spray tower is provided with a demisting filler layer.
As a preferred embodiment of the nitrogen oxide-containing tail gas treatment system, heat exchange coils are arranged in the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank.
The invention also provides a method for treating the tail gas containing the nitrogen oxides, which comprises the following steps:
(1) mixing the nitrogen oxide with air, and spraying with water;
(2) spraying the nitrogen oxide subjected to spraying treatment with alkaline liquor;
(3) and spraying the nitrogen oxide subjected to spraying treatment by using the alkaline solution by using an oxidant solution.
The invention has the beneficial effects that: the invention provides a nitrogen oxide-containing tail gas treatment system. The nitrogen oxide-containing tail gas treatment system has high absorption efficiency, the treatment reaches the standard, the highest absorption efficiency can reach 99.5 percent, and the emission concentration of nitrogen oxide is less than or equal to 200mg/m3Low investment and operation cost, high integration level and large operation flexibility. Each absorption treatment unit of the device is an independent mechanism, and can be operated and controlled independently, so that the tail gas at the outlet can be ensured to reach the standard and be discharged under the most economic condition; the maintenance and adjustment do not need the shutdown of the whole system, and the continuity of the absorption treatment can be ensured. The absorption liquid with high solute content is used for treating the waste gas with higher concentration, the absorption liquid with low solute content is used for treating the waste gas with lower concentration, the discharged waste gas is ensured to be better purified, and the waste of the absorption liquid and the subsequent treatment cost can be avoided by discharging the absorption liquid with high solute content. The automatic replacement of water between the water tanks is realized by adopting universal accessories such as the ball float valve and the siphon, the automatic replacement is simple and practical, and the failure rate is lower.
Drawings
FIG. 1 is a schematic structural diagram of a nitrogen oxide tail gas treatment system according to an embodiment;
FIG. 2 is a schematic view of the structure of a water tank;
FIG. 3 is a schematic structural view of the spraying device of the present invention;
FIG. 4 is an enlarged isometric view of the sump;
wherein, 1, a buffer tank; 101. an air inlet; 102. a nitrogen oxide inlet; 2. a first spray tower; 201. a first water tank; 2001. a first stage water tank; 2012. a second-stage water tank; 2013. a third stage water tank; 2014. a water replenishing valve; 2015. a drain valve; 2016. a water replenishing ball float valve; 2017. a siphon tube; 2018. a siphon float valve; 2019. controlling the floating ball; 20110. a water outlet; 20111. a float member; 21112. a first liquid inlet; 20113. a first drain port; 20114 a second liquid inlet; 20115. a second liquid discharge port; 20116. a third liquid inlet; 20117. a third liquid discharge port; 202. a first stage of purification equipment; 203. a gas permeable pipe; 2031. a water retaining cap; 204. a first stage sump; 205. a first drain pipe; 206. a first liquid inlet pipe; 207. a first liquid inlet pump; 3. a second spray tower; 301. a second water tank; 4. a third spray tower; 401. a third water tank; 5. a fourth spray tower; 501. a fourth water tank; 6. a fifth spray tower; 601. a fifth water tank; 7. a filler layer; 8. a spraying device; 9. and a demisting filler layer.
Detailed Description
To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.
Examples
In an embodiment of the system for treating tail gas containing nitrogen oxides, the system for treating tail gas containing nitrogen oxides in this embodiment includes a buffer tank 1, a first spray tower 2, a second spray tower 3, a third spray tower 4, a fourth spray tower 5 and a fifth spray tower 6, wherein the first spray tower 2, the second spray tower 3, the third spray tower 4, the fourth spray tower 5 and the fifth spray tower 6 all include three packing layers 7, and a spray device 8 is arranged above the packing layers of the first spray tower 2, the second spray tower 3, the third spray tower 4 and the fourth spray tower 5; and the upper parts of two packing layers below the fifth spray tower 6 are respectively provided with a spray device, and the packing layer at the uppermost layer is a demisting packing layer 9 and is arranged at an air outlet at the top and used for removing water vapor in the gas.
The bottom of the first spray tower 2 is provided with an air inlet, the air inlet of the first spray tower 2 is connected with an air outlet of the buffer tank 1, and the buffer tank 1 is provided with an air inlet 101 and a nitrogen oxide inlet 102.
The top 2 of the first spray tower is communicated with the side wall of the top of the second spray tower 3 through a sealed pipeline, the bottom of the second spray tower 3 is communicated with the bottom of the third spray tower 4 through a sealed pipeline, the top of the third spray tower 4 is communicated with the side wall of the top of the fourth spray tower 5 through a sealed pipeline, and the bottom of the fourth spray tower 5 is communicated with the bottom of the fifth spray tower 6 through a sealed pipeline; an exhaust port is arranged at the top of the fifth spray tower, and the first spray tower 2, the second spray tower 3, the third spray tower 4, the fourth spray tower 5 and the fifth spray tower 6 are respectively connected with a first water tank 201, a second water tank 301, a third water tank 401, a fourth water tank 501 and a fifth water tank 601 through water pumps; the first water tank 201, the second water tank 301, the third water tank 401, the fourth water tank 501 and the fifth water tank 601 are filled with spraying liquid; the spraying liquid in the first water tank 201 and the second water tank 301 is water; the spray liquid in the third water tank 401 and the fourth water tank 501 is sodium hydroxide solution; the spray liquid in the fifth water tank 601 is an oxidant solution;
the oxidant solution may be at least one selected from sodium perchlorate, sodium chlorate, sodium chlorite, sodium percarbonate, and sodium persulfate. Heat exchange coils (not shown in the figure) are arranged in the first water tank 201, the second water tank 301, the third water tank 401, the fourth water tank 501 and the fifth water tank 601.
When the nitrogen oxide-containing tail gas treatment system is used, air and waste gas containing nitrogen oxide are introduced into the buffer tank 1 according to a certain proportion, the waste gas in the buffer tank 1 enters the first spray tower 2 from the air inlet at the bottom of the first spray tower 2, the waste gas flows from bottom to top, the spray device 8 sprays water from top to bottom, part of nitrogen dioxide is dissolved in water, part of nitrogen dioxide is oxidized into nitrogen dioxide, nitrogen dioxide which is not dissolved in water enters the top of the second spray tower 3 from the top of the first spray tower 2 along with air flow, the nitrogen dioxide contacts with spray liquid in the second spray tower 3 from top to bottom, part of nitrogen dioxide is continuously dissolved in water, part of waste gas which is not dissolved enters the third spray tower 4 and contacts with sodium hydroxide in the third spray tower 4 and the fourth spray tower 5, part of nitrogen dioxide in air flow is continuously dissolved, the content absorption efficiency of the waste gas after the waste gas comes out of the fourth spray tower reaches more than 90%, and then enters a fifth spray tower 6, the final strengthening treatment is carried out in the fifth spray tower 6, the nitrogen oxide is basically completely converted into nitrogen dioxide after being treated by an oxidant, and the nitrogen dioxide can be directly discharged into the air after being demisted by the demisting filler at the air outlet at the top.
In the present embodiment, the first water tank 201, the second water tank 301, the third water tank 401, the fourth water tank 501 and the fifth water tank 601 are all multi-stage water tanks, and the structure of the first water tank is taken as an example for specific details, and the structures of the second water tank, the third water tank, the fourth water tank and the fifth water tank and the connection relationship between the second water tank, the third water tank, the fourth water tank and the fifth water tank and the spray tower can be analogized from this.
The structural schematic diagram of the first water tank 201 is shown in fig. 2, the number of stages of the first water tank 201 is 3, three water tanks are sequentially stacked from bottom to top, a first-stage water tank 2011 is positioned at the top, a second-stage water tank 2012 is positioned below the first-stage water tank 2011, a third-stage water tank 2013 is positioned at the bottom, a water replenishing port is arranged on the first-stage water tank 2011, a water replenishing valve 2014 is arranged on the water replenishing port, a water discharging port is arranged on the third-stage water tank 2013, a water discharging valve 2015 is arranged on the water discharging port, and the water replenishing port is; the upper and lower adjacent two-layer water tank is communicated through a siphon 2017, the siphon 2017 that is located superior water tank is called upper end siphon, the siphon that is located subordinate water tank is called lower end siphon, be equipped with the water inlet on the upper end siphon that is located superior water tank, be equipped with delivery port 20110 on the lower extreme siphon pipe wall that is located inferior water tank, all be equipped with siphon ball float valve 2018 in other water tanks except that tertiary water tank, the switching of delivery port 20110 on siphon pipe wall is gone up in siphon ball float valve 2018 control lower extreme siphon, and when the water level dropped to minimum settlement position, siphon ball float valve 2018 control delivery port 20110 was opened, and when the water level rose to the highest settlement position, siphon ball float valve 2018 control delivery port.
The siphon float valve 2018 is sleeved on the lower end siphon, the siphon float valve 2018 can move up and down along the lower end siphon relatively, and the relative movement of the siphon float valve 2018 and the lower end siphon is used for controlling the opening and closing of the water outlet 20110.
The siphon float valve 2018 is connected with the control float 2019 through a float connecting rod (not shown in the figure), the other end of the control float 2019 is fixedly arranged on the top wall, a vertical chute (not shown in the figure) is formed in the siphon float valve 2018, the float connecting rod can move up and down relatively along the chute, the siphon float valve 2018 can descend along with descending of the water level in the water level descending process, the control float 2019 controls the siphon float valve 2018 not to move relative to a lower end siphon through the float connecting rod before the water level ascends to a highest set position in the water level ascending process, and the control float 2019 drives the siphon float valve 2018 to move upwards through the float connecting rod to control the water outlet 20110 to be closed when the water level ascends to the highest set position. A floating member 20111 is fixedly arranged at the bottom of the siphon float valve 2018, and the floating member 20111 can enable the siphon float valve 2018 to have certain buoyancy and to descend along with the descending of the water level.
The structural schematic diagram of the first spray tower is shown in fig. 3 and 4, the first spray tower is provided with three levels of purification equipment which are sequentially arranged from top to bottom, the second level of purification equipment is positioned below the first level of purification equipment, the third level of purification equipment is positioned at the lowest part, the first level of purification equipment is positioned at the uppermost part, the first level of purification equipment 202 comprises a first level liquid collecting tank 204, the bottom of the first level liquid collecting tank 204 is communicated with a first liquid inlet 20112 of a first level water tank 2011 through a first liquid discharge pipe 205, and a first liquid discharge port 20113 of the first level water tank 2011 is connected with a spray assembly of the first level of purification equipment 202 through a first liquid inlet pipe 206 and a first liquid inlet pump 207; similarly, the second-stage purification equipment comprises a second-stage liquid collecting tank, the bottom of the second-stage liquid collecting tank is communicated with a second liquid inlet 20114 of the second-stage water tank 2012 through a second liquid outlet pipe, and a second liquid outlet 20115 of the second-stage water tank 2012 is connected with a spraying assembly of the second-stage purification equipment through a second liquid inlet pipe and a second liquid inlet pump; the third-level purification equipment comprises a third-level liquid collecting tank, the bottom of the third-level liquid collecting tank is communicated with a third liquid inlet 20116 of a third-level water tank 2013 through a third liquid discharge pipe, and a third liquid discharge port 20117 of the third-level water tank 2013 is connected with a spraying assembly of the third-level purification equipment through a third liquid inlet pipe and a third liquid inlet pump.
The first spray tower 2 is provided with an observation port corresponding to each purification device, in the first-stage purification device 202, the upper port of the vent pipe 203 is higher than the bottom of the first-stage liquid collecting tank 204, and the lower port of the vent pipe 203 is fixedly connected with the bottom of the first-stage liquid collecting tank 204; similarly, in the second-stage purification equipment, the upper port of the vent pipe is higher than the bottom of the second-stage liquid collecting tank, and the lower port of the vent pipe is fixedly connected with the bottom of the second-stage liquid collecting tank; in the third-stage purifying equipment, the upper port of the vent pipe is higher than the bottom of the third-stage liquid collecting tank, and the lower port of the vent pipe is fixedly connected with the bottom of the third-stage liquid collecting tank.
After entering the first spray tower 2, the waste gas is purified by multi-stage purification equipment and then discharged to a second spray tower from the top; each level of purification equipment adopts a module design, and modules of the purification equipment can be added or reduced so as to achieve different purification effects; each level of purification equipment is provided with a packing layer, a water retaining cap 2031, a liquid collecting tank and a vent pipe 203, so that the independence of each level of purification equipment is ensured; the lower waste gas enters the purifying equipment from the vent pipe 203 for purifying treatment. The absorption liquid which has absorbed the exhaust gas is stored in the liquid collecting tank, and the absorption liquid in the liquid collecting tank flows into the first water tank 201 through the liquid discharge pipe; the absorption liquid in the first water tank 201 flows into the spraying assembly through the liquid inlet pump and the liquid inlet pipe. When the top discharge gas is monitored to reach a set value or reach a preset time, the saturated absorption liquid is discharged through a drain valve 2015; the drainage process of the water tank specifically comprises the following steps: when the concentration of the top waste gas is detected to reach a set value or a preset time is reached, a drain valve 2015 on a water outlet of the third-stage water tank 2013 is opened, the water level is lowered, a siphon ball float valve 2018 is lowered along a lower-end siphon pipe along with the lowering of the water level, a ball float link moves downwards along a vertical chute, when the water level is lowered to a lowest set position, the siphon ball float valve 2018 controls a water outlet 20110 on the lower-end siphon pipe to be opened, water in the second-stage water tank 2012 flows out from the water outlet of the third-stage water tank 2013 through a siphon pipe, the water level in the third-stage water tank 2013 is raised, the water level in the second-stage water tank 2012 is lowered at the same time, before the water level in the third-stage water tank 2013 is raised to a highest set position, the ball float 2019 is controlled to control the siphon ball float valve 2018 not to move relative to the siphon, the control floating ball 2019 drives the siphon floating ball valve 2018 to move upwards through the floating ball connecting rod to control the water outlet 20110 to be closed, water in the second-stage water tank 2012 stops flowing in, and displacement of the water from the second-stage water tank 2012 to the third-stage water tank 2013 is finished. Similarly, when the water level in the second-stage water tank 2012 drops to the lowest set position, the water passes through the siphon and the siphon ball float valve to realize the displacement of the first-stage water tank 2011 to the second-stage water tank 2012, and when the water level in the first-stage water tank 2011 is lower than the set position, the water replenishing ball float valve 2016 is triggered to open to replenish water to the first-stage water tank 2011, so that the displacement progressive water changing of the whole water tank is realized. Therefore, the absorption liquid with high solute content is used for treating the waste gas with higher concentration, the absorption liquid with low solute content is used for treating the waste gas with lower concentration, the discharged waste gas is ensured to be better purified, and the waste of the absorption liquid and the subsequent treatment cost can be avoided by discharging the absorption liquid with high solute content.
Through detection, the nitrogen oxide treated by the nitrogen oxide-containing tail gas treatment system can ensure that the absorption efficiency reaches 99.5 percent to the maximum extent and the emission concentration of the nitrogen oxide is less than or equal to 200mg/m3。
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (8)
1. The nitrogen oxide-containing tail gas treatment system is characterized by comprising a first spray tower, a second spray tower, a third spray tower, a fourth spray tower and a fifth spray tower, wherein the first spray tower, the second spray tower, the third spray tower, the fourth spray tower and the fifth spray tower respectively comprise at least two packing layers, the bottom of the first spray tower is provided with a gas inlet, the top of the first spray tower is communicated with the side wall of the top of the second spray tower through a sealing pipeline, the bottom of the second spray tower is communicated with the bottom of the third spray tower through a sealing pipeline, the top of the third spray tower is communicated with the side wall of the top of the fourth spray tower through a sealing pipeline, and the bottom of the fourth spray tower is communicated with the bottom of the fifth spray tower through a sealing pipeline; the first spray tower, the second spray tower, the third spray tower, the fourth spray tower and the fifth spray tower are respectively connected with a first water tank, a second water tank, a third water tank, a fourth water tank and a fifth water tank through water pumps; the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank are all filled with spraying liquid; the spraying liquid in the first water tank and the second water tank is water; the spraying liquid in the third water tank and the fourth water tank is alkaline solution; the spray liquid in the fifth water tank is oxidant solution;
at least one of the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank is a multi-stage water tank, the stage number of the multi-stage water tank is n stages, n is more than or equal to 2, the n stages of water tanks are sequentially overlapped from top to bottom, the second stage water tank is positioned below the first stage water tank, the nth stage water tank is positioned at the bottom, a water replenishing port is arranged on the first stage water tank, a water outlet is arranged on the nth stage water tank, and the water replenishing port is communicated with each stage of water tank through a water replenishing ball float valve; the upper and lower adjacent two-stage water tanks are communicated through a siphon pipe, the upper end siphon pipe positioned in the upper layer water tank is provided with a water inlet, the lower end siphon pipe wall positioned in the lower layer water tank is provided with a water outlet, the other water tanks except the nth stage water tank are respectively provided with a siphon ball float valve, the siphon ball float valve controls the opening and closing of the water outlet on the lower end siphon pipe wall, when the water level is lowered to the lowest set position, the siphon ball float valve controls the water outlet to be opened, and when the water level is raised to the highest set position, the siphon ball float valve;
the spray tower connected with the multi-stage water tanks is a multi-stage spray tower, the multi-stage spray tower is provided with N stages of purification equipment which are sequentially arranged from top to bottom, N is more than or equal to 2, the second stage of purification equipment is positioned below the first stage of purification equipment, the Nth stage of purification equipment is positioned at the lowest part, the first stage of purification equipment is positioned at the highest part, the purification equipment comprises a spray component, a packing layer and liquid collecting tanks for collecting absorption liquid are sequentially fixed below the spray component, and the bottom of each liquid collecting tank is respectively connected with one stage of water tanks in the multi-stage water tanks through liquid discharge pipes; each stage of water tank is provided with a liquid inlet and a liquid outlet, the liquid inlets on two adjacent layers of water tanks are respectively communicated with a liquid discharge pipe at the bottom of a liquid collecting tank on two adjacent layers of purification equipment, and the liquid outlets on two adjacent layers of water tanks are respectively communicated with spraying assemblies on two adjacent layers of purification equipment;
the siphon float valve is sleeved on the lower end siphon pipe, the siphon float valve can move up and down along the lower end siphon pipe relatively, the water outlet is arranged on the pipe wall of the lower end siphon pipe, and the relative movement of the siphon float valve and the siphon pipe is used for controlling the opening and closing of the water outlet;
the siphon ball cock is connected with the control floating ball through the floating ball connecting rod, the other end of the control floating ball is fixedly arranged on the top wall, a vertical sliding groove is formed in the siphon ball cock, the floating ball connecting rod can move up and down relatively along the sliding groove, the siphon ball cock can descend along with the descending of the water level, the control floating ball controls the siphon ball cock to not move relative to the siphon pipe through the floating ball connecting rod before the water level rises to the highest set position, and when the water level rises to the highest set position, the control floating ball drives the siphon ball cock to move upwards through the floating ball connecting rod to control the closing of the water outlet.
2. The nitrogen oxide-containing tail gas treatment system of claim 1, wherein the liquid discharge end of the upper water tank is connected with the spray assembly of the upper purification equipment through a liquid inlet pipe, a valve and a liquid inlet pump, and the liquid discharge end of the lower water tank is connected with the spray assembly of the lower purification equipment through a liquid inlet pipe, a valve and a liquid inlet pump.
3. The nitrogen oxide-containing tail gas treatment system according to claim 2, wherein the liquid collection tank is provided with a gas inlet of a gas permeable pipe for gas to pass through, and the upper port of the gas permeable pipe is positioned higher than the bottom of the liquid collection tank.
4. The nitrogen oxide-containing tail gas treatment system of claim 3, wherein the top of the liquid collecting tank is provided with an opening, the side wall of the liquid collecting tank is tightly attached to the inner wall of the spray tower, and a water retaining cap is arranged above the upper port of the gas permeable pipe and used for blocking liquid from flowing into the gas permeable pipe.
5. The nitrogen oxide-containing tail gas treatment system of claim 1, wherein the gas inlet of the first spray tower is connected with the gas outlet of a buffer tank, and the buffer tank is provided with an air inlet and a nitrogen oxide inlet.
6. The nitrogen oxide-containing tail gas treatment system according to claim 1, wherein the oxidant solution is at least one of sodium perchlorate, sodium chlorate, sodium chlorite, sodium percarbonate, and sodium persulfate; the alkali solution is sodium hydroxide solution.
7. The nitrogen oxide-containing tail gas treatment system of claim 1, wherein a demisting packing layer is arranged at an air outlet at the top of the fifth spray tower.
8. The nitrogen oxide-containing tail gas treatment system of claim 1, wherein heat exchange coils are disposed in the first water tank, the second water tank, the third water tank, the fourth water tank and the fifth water tank.
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| CN201811464106.1A CN109432983B (en) | 2018-11-30 | 2018-11-30 | Nitrogen oxide-containing tail gas treatment system |
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Address after: 529000 1st floor, building 2, 318 Waihai Nanshan Road, Jianghai District, Jiangmen City, Guangdong Province (self edited 03) Patentee after: Jotun (Guangdong) Environmental Technology Co.,Ltd. Address before: 529000 1st floor, building 2, 318 Waihai Nanshan Road, Jianghai District, Jiangmen City, Guangdong Province (self edited 03) Patentee before: JIANGMEN ZUODUN ENVIRONMENTAL PROTECTION TECHNOLOGY Co.,Ltd. |