CN116392963A - Quick removal of NO from ship engine X Radial denitration device and denitration method of (2) - Google Patents
Quick removal of NO from ship engine X Radial denitration device and denitration method of (2) Download PDFInfo
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- 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
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9431—Processes characterised by a specific device
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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
- B01D53/48—Sulfur compounds
- B01D53/50—Sulfur oxides
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- 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
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
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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
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
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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
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9459—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2251/00—Reactants
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- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
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Abstract
The invention provides a radial denitration device and a denitration method for rapidly removing NOx of a ship engine, and SO in the invention 2 The absorption device is arranged at the front end of the NO pre-oxidation device, the NO pre-oxidation device is divided into an inner pipeline and an outer pipeline, an electronic control valve is arranged in the inner pipeline, and the bypass air quantity is controlled by adjusting the opening of the electronic control valve on the inner pipeline so as to adjust NO and NO 2 The purpose of the ratio; the tail gas of the ship is firstly treated by SO 2 Absorption device for removing small amount of SO in waste gas 2 Then through NO pre-oxidizing device, partial NO is oxidized into NO 2 The oxidized ship tail gas and urea solution are pyrolyzed and hydrolyzed to form NH 3 Together with selectivity of entryAnd a catalytic reduction device for generating a rapid SCR reaction. Quick removal of NO from ship engine X The radial denitration device and the radial denitration method greatly improve the SCR reaction rate and the denitration efficiency through the rapid SCR reaction, and reduce the SCR reaction temperature requirement.
Description
Technical Field
The invention belongs to the technical field of ship low-sulfur/zero-sulfur fuel engine tail gas treatment, and particularly relates to a method for rapidly removing NO from a ship engine X Is provided.
Background
The high temperature combustion of the marine engine is a major cause of NO production in the marine exhaust gases. N in intake air of ship engine under high temperature condition 2 The NOx in the ship tail gas is the main pollutant of the ocean atmosphere and coastal city air, and the environmental damage is caused and the human health is seriously influenced. The International Maritime Organization (IMO) has been severely restricted in terms of emissions from marine vessels, wherein the MARBOL convention TierIII emission standard was formally implemented for marine engines NO at 1/2016 X Presents a great challenge for emissions control, and numerous research institutions are also in marine NO X There are numerous achievements in emissions control.
Selective Catalytic Reduction (SCR) technology is currently the most effective denitration technology. At present, the marine SCR technology mainly adopts the standard SCR technology, and NH generated by urea aqueous solution 3 As a reducing agent, the NO in the ship tail gas is reacted with the catalyst X Reduction of (mainly NO) to N 2 . At present, the standard SCR technology is mature, but has the problems of slower SCR reaction rate, overlarge reactor volume, high reaction temperature requirement and the like, and seriously influences the application of SCR on ships (in particular to a post-turbine SCR mode). The rapid SCR reaction increases NO in nitrogen oxides compared to standard SCR reactions 2 Ratio (about 50%), NO and NO 2 At the same time with NH 3 And (3) reacting. The reaction rate of the rapid SCR reaction is 10 times that of the standard SCR reaction, and the rapid SCR reaction has a lower reaction temperature and a higher low-temperature reaction efficiency.
Disclosure of Invention
In view of this, NO is present in the existing marine exhaust gases mentioned in the background art above X The invention provides a method for rapidly removing NO from a ship engine, which solves the problems of the treatment method X The radial denitration device and the denitration method are low in reaction temperature requirement, high in low-temperature activity, high in reaction rate, small in volume and long in service life.
In order to achieve the above purpose, the present invention adopts the following technical scheme: quick desorption ship engine NO X Comprises a three-way valve and SO 2 The device comprises an absorption device, a NO pre-oxidation device, a urea injection system, a selective catalytic reduction device and a control unit, wherein the three-way valve and SO 2 The absorption device, the NO pre-oxidation device, the urea injection system and the selective catalytic reduction device are sequentially connected, and the ship tail gas is discharged from the ship engine, passes through a three-way valve and then passes through SO 2 Absorption device for absorbing small amount of SO in ship tail gas 2 Absorbing and then reaching the NO pre-oxidation device, and oxidizing part of NO in the ship tail gas into NO 2 The tail gas from the NO pre-oxidation device passes through a pipeline provided with a urea injection system, is mixed with urea aqueous solution and then enters a selective catalytic reduction device, a rapid SCR reaction is carried out in the selective catalytic reduction device, and NO in the tail gas X Is reduced to N 2 The treated tail gas is directly discharged to the atmosphere through an exhaust pipeline, and the ship tail gas is directly discharged to the atmosphere through a bypass of a three-way valve when faults occur.
Still further, the SO 2 The absorption device adopts an alkaline absorbent to remove SO in the tail gas 2 。
Still further, urea injection system includes injection apparatus, electronic control valve and urea holding vessel, urea injection apparatus, electronic control valve and urea holding vessel connect gradually, the controlled bill of control valve of No. oneMeta-control, mixing ship tail gas with urea solution sprayed by a urea spraying device, and performing pyrolysis and hydrolysis reaction on the urea solution under the action of tail gas waste heat to generate NH (NH) 3 。
Further, the NO pre-oxidation device comprises a pipeline, an oxidation catalyst, a second electronic control valve, a NO sensor and NO 2 The pipeline comprises an outer pipeline and an inner pipeline, the oxidation catalyst is arranged in the outer pipeline, the second electronic control valve is arranged in the middle of the inner pipeline, and the opening of the second electronic control valve is composed of an NO sensor and an NO 2 The sensor transmits back the control signal of the control unit to determine that the NO/NO is realized by adjusting the gas quantity of the inner pipeline and the outer pipeline 2 Ratio maintenance 1: 1.
Further, partial NO in the ship tail gas is oxidized into NO in a NO pre-oxidizing device 2 Then the oxidized ship tail gas is pyrolyzed and hydrolyzed with NH generated by urea solution 3 Mixing, and entering a selective catalytic reduction device together to generate a rapid SCR reaction.
Still further, selective catalytic reduction device includes casing, anti-backflow board, intake duct, no. one sealing baffle, exhaust duct, reduction catalyst, isolation net and No. two sealing baffle, be equipped with anti-backflow board and No. two sealing baffle respectively in the selective catalytic reduction device horizontal front and back, the centre is provided with the column isolation net axially, is the intake duct in the column isolation net, and reduction catalyst has been placed to column isolation net periphery.
Furthermore, a cavity is formed between the reduction catalyst and the shell to form an exhaust passage, a first sealing baffle is arranged at the front end of the exhaust passage, ship tail gas radially flows through the reduction catalyst and then enters the exhaust passage, the reduction catalyst and the shell are converged at a conical pipe at the outlet end of the selective catalytic reduction device, and finally the tail gas is discharged to the atmosphere from a tail gas outlet.
Further, the outlet end of the selective catalytic reduction device is provided with NO X Sensor and NH 3 Sensor, NO X Sensor and NH 3 The sensor transmits the detection signal to the control unit, and the opening degree of the first electronic control valve is adjusted by the control unitAnd adjusting the spraying amount of urea.
The method is used for rapidly removing NO from ship engine X The method for denitration by the radial denitration device comprises the following steps:
step 1: the tail gas of the ship enters SO 2 In the absorption device, in SO 2 Small amount of SO in the tail gas of the ship is absorbed under the action of the absorbent 2 Removing;
step 2: the ship tail gas enters a NO pre-oxidation device, and partial NO in the ship tail gas is oxidized into NO through a pre-oxidation catalyst 2 An NO sensor and NO are arranged at the outlet end of the NO pre-oxidation device 2 The sensor and the two sensors send concentration signals into the control unit to calculate NO/NO 2 By comparing the set value, outputting an electric signal to adjust the opening of a second electronic control valve in the NO pre-oxidation device, and adjusting the gas bypass quantity to realize the NO and NO 2 Regulation of the ratio to make NO/NO 2 The ratio is controlled to be 1:1;
step 3: the pre-oxidized ship tail gas is led to a selective catalytic reduction device through an exhaust pipe, wherein the tail gas is mixed with urea spray sprayed by a urea spraying device in the exhaust pipe, and urea aqueous solution is decomposed to generate NH under the action of high temperature 3 ；
Step 4: the mixed ship tail gas enters a selective catalytic reduction device, the mixed tail gas enters a selective catalytic reduction catalyst from the radial direction of the selective catalytic reduction device to carry out rapid SCR reaction, and NO in the ship tail gas X Is catalytically reduced to N 2 ；
Step 5: NO at outlet end of selective catalytic reduction device X Sensor and NH 3 The sensor detects the processed ship tail gas, sends the measured value into the control unit, and then adjusts the first electronic control valve 8 through the control unit to control the spraying amount of urea so as to enable NO X The final emissions meet regulatory requirements.
Compared with the prior art, the method for rapidly removing NO in the ship engine X The radial denitration device and the denitration method have the beneficial effects that:
(1) NeedleThe invention provides a radial denitration device for rapidly removing NOx of a ship engine, which solves the problems of slow denitration rate, overlarge reactor volume and the like in the prior SCR technology of ships, and changes the traditional ship tail gas treatment mode. The invention is based on rapid SCR reaction, and is used for treating NO in ships X The treatment is carried out, so that the requirements on the reaction temperature of SCR are reduced and the volume of the SCR reactor is reduced while the denitration rate and the denitration efficiency are improved; the reactor adopts a radial air inlet mode to increase the contact area between the ship tail gas and the catalyst, shortens the reaction time, reduces the back pressure, and can remarkably improve the SCR reaction rate and the low-temperature removal efficiency based on the marine radial denitration device of the rapid SCR reaction.
(2) Compared with the existing marine SCR device, the radial denitration device for rapidly removing NOx of the marine engine is SO 2 The absorption device can protect the rapid SCR reaction catalyst from sulfur poisoning, so that the conversion efficiency of the SCR catalyst is improved, and the service life of the SCR catalyst is prolonged; NO pre-oxidation device is arranged on NO sensor and NO 2 Synergistic effect of sensor, electronic control valve and control unit to realize NO 2 Dynamic adjustment of concentration ensures that the rapid SCR reaction is in an optimal state and promotes the occurrence of the rapid SCR reaction.
(3) Compared with the existing ship denitration device, the invention adopts the mode that the tail gas radially flows through the catalyst, realizes larger contact area between the tail gas and the catalyst, avoids damage to the catalyst caused by non-uniformity of speed and pressure at the inlet end of the ship tail gas in the denitration reactor, and can effectively prolong the service life of the catalyst.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
FIG. 1 is a schematic structural diagram of a radial denitration device for rapidly removing NOx from a ship engine, which is implemented by the invention;
FIG. 2 is a schematic diagram of SO in a denitrification facility according to the invention 2 Schematic cross-sectional structure of the absorption device;
FIG. 3 is a schematic cross-sectional view of a NO pre-oxidation apparatus of the denitration apparatus of the present invention;
FIG. 4 is a schematic cross-sectional view of a selective catalytic reduction device of the denitration device according to the present invention;
FIG. 5 is a schematic cross-sectional view of a selective catalytic reduction device of the denitration device according to the present invention;
in the above figures, the reference numerals have the following meanings: 1-a three-way valve; 2-SO 2 An absorption device; 3-NO pre-oxidation device; a 4-NO sensor; 5-NO 2 A sensor; 6-urea injection system; 7-urea injection device; 8-electronic control valve number one; 9-urea storage tank; 10-a selective catalytic reduction device; 11-NO X A concentration sensor; 12-NH 3 A sensor; 13-a control unit; 14-SO 2 An absorbent; 15-an oxidation catalyst; 16-second electronic control valve; 17-a housing; 18-a backflow prevention plate; 19-an air inlet channel; 20-a first sealing baffle; 21-an exhaust passage; 22-reducing the catalyst; 23-metal isolation net; 24-second sealing baffle.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that, in the case of no conflict, embodiments of the present invention and features of the embodiments may be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.
1. Detailed description of the preferred embodimentthe present embodiment is described with reference to fig. 1-5, a rapid removal of engine NO from a ship X Comprises a three-way valve 1 and SO 2 The absorption device 2, the NO pre-oxidation device 3, the urea injection system 6, the selective catalytic reduction device 10 and the control unit 13, and the three-way valve 1 and the SO 2 The absorption device 2, the NO pre-oxidation device 3, the urea injection system 6 and the selective catalytic reduction device 10 are sequentially connected, and the ship tail gas is discharged from the ship engine, passes through the three-way valve 1 and then passes through SO 2 An absorber 2 for absorbing a small amount of SO in the tail gas of a ship 2 Absorbed and then reaches the NO pre-oxidation device 3, and part of NO in the ship tail gas is oxidized into NO 2 Preoxidation from NOThe tail gas from the device 3 passes through a pipeline provided with a urea injection system 6, is mixed with urea aqueous solution and then enters a selective catalytic reduction device 10, the rapid SCR reaction is carried out in the selective catalytic reduction device 10, and NO in the tail gas X Is reduced to N 2 The treated tail gas is directly discharged to the atmosphere through an exhaust pipeline, and the ship tail gas is directly discharged to the atmosphere through the bypass of the three-way valve 1 when the ship tail gas fails.
The SO 2 The absorption device 2 adopts an alkaline absorbent to remove SO in the tail gas 2 。
The urea injection system 6 comprises a urea injection device 7, a first electronic control valve 8 and a storage tank 9, wherein the urea injection device 7, the first electronic control valve 8 and the storage tank 9 are sequentially connected, the first electronic control valve 8 is controlled by a control unit 13, ship tail gas is mixed with urea solution injected by the urea injection device 7, and under the action of tail gas waste heat, the urea solution is subjected to pyrolysis and hydrolysis reaction to generate NH 3 。
The NO pre-oxidation device 3 comprises a pipeline, an oxidation catalyst 15, a second electronic control valve 16, a NO sensor 4 and NO 2 The sensor 5, the pipeline includes an outer layer pipeline and an inner layer pipeline, the oxidation catalyst 15 is arranged in the outer layer pipeline, the second electronic control valve 16 is arranged in the middle of the inner layer pipeline, and the opening of the second electronic control valve 16 is composed of the NO sensor 4 and NO 2 The sensor 5 transmits back the control signal of the control unit 13 to determine whether NO/NO is achieved by adjusting the gas quantity of the inner and outer pipelines 2 Ratio maintenance 1: 1.
Part of NO (about 50%) in the ship tail gas is oxidized to NO in the NO pre-oxidizing device 3 2 Then the oxidized ship tail gas is pyrolyzed and hydrolyzed with NH generated by urea solution 3 Mixed together into the selective catalytic reduction device 10 where a rapid SCR reaction occurs. The reaction rate is 10 times of that of the standard SCR reaction rate for treating the ship tail gas, and the invention has higher low-temperature reaction efficiency while reducing the requirement of SCR reaction temperature.
The selective catalytic reduction device 10 comprises a shell 17, a backflow prevention plate 18, an air inlet 19, a first sealing baffle 20, an air outlet 21, a reduction catalyst 22, an isolation net 23 and a second sealing baffle 24, wherein the backflow prevention plate 18 and the second sealing baffle 24 are respectively arranged in the selective catalytic reduction device 10 in the transverse direction front and back, a columnar isolation net 23 is axially arranged in the middle of the selective catalytic reduction device, the air inlet 19 is arranged in the columnar isolation net 23, and the reduction catalyst 22 is placed on the periphery of the columnar isolation net 23.
A cavity is formed between the reduction catalyst 22 and the shell 17 to form an exhaust passage 21, a first sealing baffle 20 is arranged at the front end of the exhaust passage 21, ship exhaust radially flows through the reduction catalyst 22, then enters the exhaust passage 21, merges at a conical pipe at the outlet end of the selective catalytic reduction device 10, and finally is discharged to the atmosphere from an exhaust outlet.
The outlet end of the selective catalytic reduction device 10 is provided with NO X Sensor 11 and NH 3 Sensor 12, NO X Sensor 11 and NH 3 The sensor 12 transmits a detection signal to the control unit 13, and the opening degree of the first electronic control valve 8 is adjusted by the control unit 13 to adjust the injection amount of urea.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in detail below with reference to the accompanying drawings:
as shown in fig. 1, the tail gas of the ship sequentially passes through a three-way valve 1 and SO after coming out of the ship engine 2 The absorption device 2, the NO pre-oxidation device 3 and the selective catalytic reduction device 10 are finally discharged into the atmosphere through a ship tail gas outlet. Compared with the traditional denitration device, the denitration device has the advantages of higher SCR reaction rate and higher denitration efficiency under the low-temperature condition, and SO 2 The absorption device 2 can remove a small amount of SO in the tail gas of the ship 2 The NO pre-oxidation device 3 can dynamically adjust NO/NO by adjusting the opening degree of the second electronic control valve 16 through the control unit 13 to prevent the catalyst in the NO pre-oxidation device 3 from being poisoned and deactivated 2 Is of a value of (1) such that NO and NO 2 The ratio of (2) is in a set ratio, and the selective catalytic reduction device 10 can effectively reduce the exhaust back pressure by adopting a radial air inlet mode.
Marine tail gas entry, SO as shown in figure 2 2 In the absorption device 2, the SO 2 The absorption device 2 mainly comprises SO 2 Absorber 14, small amount of marine tail gasSO 2 Will sum SO 2 The absorbent reacts with SO 2 Is removed.
In the NO pre-oxidation device 3 shown in fig. 3, a part of the ship exhaust gas directly flows out of the NO pre-oxidation device 3 from the inner pipeline, and the other part of the ship exhaust gas enters the oxidation catalyst 15 of the outer pipeline, wherein NO in the exhaust gas is oxidized to form NO 2 The general package reaction equation is shown below:
specifically, as shown in fig. 3, in the NO pre-oxidation device 3, if the opening of the second electronic control valve 16 is reduced, more exhaust gas flows into the outer layer pipeline, and NO is oxidized into NO 2 The gas bypass amount can be controlled by adjusting the opening degree of the second electronic control valve 16 through the control unit 13, so that NO and NO can be adjusted 2 The purpose of the ratio.
Specifically, as shown in FIG. 3, the ship exhaust gas after the oxidation reaction reaches the outlet end of the NO pre-oxidation device 3, the NO sensor 4 and NO 2 Sensor 5 measures NO and NO 2 The control unit 13 regulates and controls the opening of the second electronic control valve 16. When NO/NO 2 When the value of (2) is smaller than 1:1, the opening degree is increased, the gas bypass amount (entering the inner pipeline) is increased, and otherwise, the opening degree is reduced, so that NO/NO is realized 2 The ratio of (2) is at 1: 1.
Mixing the ship tail gas with urea solution sprayed by the urea spraying device 7, and carrying out pyrolysis and hydrolysis reaction on the urea solution under the action of tail gas waste heat to generate NH 3 The reaction formula is as follows:
the marine exhaust gas then enters the selective reduction device 10 as shown in fig. 4, where NH3 is further mixed with the oxidized marine exhaust gas and subjected to a rapid SCR reaction under the action of the reduction catalyst 22, the reaction equation is as follows:
specifically, as shown in fig. 4, the gas is mixed in the hollow portion of the apparatus and enters the reduction catalyst 22 in the radial direction of the selective catalytic reduction apparatus 10; NO, NO 2 With NH 3 The rapid SCR reaction occurs in the pore canal inside the catalyst, so that NO in the ship tail gas is effectively removed X 。
NO is arranged at the outlet end of the selective catalytic reduction device 10 X Concentration sensor 11, NH3 sensor 12, for NO in the effluent gas X And NH 3 The detection is carried out, signals are transmitted to the control unit 13, the control unit 13 regulates and controls the first electronic control valve 8, and the spraying amount of urea is changed, so that the ship tail gas can meet the emission requirement of TierIII, excessive use of urea is avoided, and ammonia escape is generated.
The invention also provides a method for denitration by the radial denitration device for rapidly removing NOx of the ship engine, which comprises the following steps:
step 1: the tail gas of the ship enters SO 2 In the absorption device 2, in SO 2 The small amount of SO in the tail gas of the ship is absorbed under the action of the absorbent (alkaline substance) 2 Removing;
step (a) 2: the ship tail gas enters the NO pre-oxidation device 3, and partial NO in the ship tail gas is oxidized into NO through the pre-oxidation catalyst 15 2 An NO sensor 4 and NO are arranged at the outlet end of the NO pre-oxidation device 3 2 A sensor 5, two sensors send concentration signals to a control unit 13 to calculate NO/NO 2 By comparing the set value, outputting an electric signal to adjust the opening of the second electronic control valve 16 in the NO pre-oxidation device 3, and adjusting the gas bypass amount to realize the NO and NO 2 Regulation of the ratio to make NO/NO 2 The ratio is controlled to be about 1:1;
step 3: the pre-oxidized marine exhaust gas is led to the selective catalytic reduction device 10 via an exhaust pipe in which the exhaust gas and urine are passedUrea sprayed by the element spraying device 7 is mixed, and the urea aqueous solution is decomposed to generate NH under the action of high temperature 3 The overall package reaction is as follows:
(NH 2 ) 2 CO+H 2 O→2NH 3 +CO 2 (4)
step 4: the mixed ship tail gas enters a selective catalytic reduction device 10, the mixed tail gas enters a selective catalytic reduction catalyst from the radial direction of the selective catalytic reduction device 10 to carry out rapid SCR reaction, and NO in the ship tail gas X Is catalytically reduced to N 2 . The main reaction formula is as follows:
step 5: NO at the outlet end of the selective catalytic reduction device 10 X Sensor 11 and NH 3 The sensor 12 detects the processed ship tail gas, sends the measured value into the control unit 13, and then adjusts the first electronic control valve 8 through the control unit 13 to control the spraying amount of urea so as to enable NO X The final emissions meet regulatory requirements.
The method for rapidly removing NOx from the ship engine by the radial denitration device is applicable to the description of engine types and is applicable to low-sulfur/zero-sulfur fuels, including but not limited to low-sulfur fuel, LNG, LPG, methanol, ethanol, ammonia, hydrogen and other fuel engines.
The embodiments of the invention disclosed above are intended only to help illustrate the invention. The examples are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best understand and utilize the invention.
Claims (9)
1. Quick desorption ship engine NO X Is characterized in that: bag(s)Includes a three-way valve (1) and SO 2 An absorption device (2), an NO pre-oxidation device (3), a urea injection system (6), a selective catalytic reduction device (10) and a control unit (13), wherein the three-way valve (1) and the SO 2 The absorption device (2), the NO pre-oxidation device (3), the urea injection system (6) and the selective catalytic reduction device (10) are sequentially connected, and the ship tail gas is discharged from the ship engine, passes through the three-way valve (1) and then passes through the SO 2 An absorption device (2) for absorbing a small amount of SO in the tail gas of the ship 2 Absorbing and then reaching the NO pre-oxidation device (3), and oxidizing part of NO in the ship tail gas into NO 2 The tail gas from the NO pre-oxidation device (3) passes through a pipeline provided with a urea injection system (6), is mixed with urea aqueous solution and then enters a selective catalytic reduction device (10), the rapid SCR reaction is carried out in the selective catalytic reduction device (10), and NO in the tail gas X Is reduced to N 2 The treated tail gas is directly discharged into the atmosphere through an exhaust pipeline, and when the ship tail gas fails, the ship tail gas is directly discharged into the atmosphere through bypass of a three-way valve (1).
2. The rapid removal of marine engine NO according to claim 1 X Is characterized in that: the SO 2 An absorption device (2) adopts an alkaline absorbent to remove SO in tail gas 2 。
3. The rapid removal of marine engine NO according to claim 1 X Is characterized in that: the urea injection system (6) comprises a urea injection device (7), a first electronic control valve (8) and a urea storage tank (9), wherein the urea injection device (7), the first electronic control valve (8) and the urea storage tank (9) are sequentially connected, the first electronic control valve (8) is controlled by a control unit (13), ship tail gas is mixed with urea solution injected by the urea injection device (7), and under the action of tail gas waste heat, the urea solution is subjected to pyrolysis and hydrolysis reaction to generate NH (NH) 3 。
4. The rapid removal of marine engine NO according to claim 1 X Is characterized in that: the NO is pre-oxidizedThe device (3) comprises a pipeline, an oxidation catalyst (15), a second electronic control valve (16), a NO sensor (4) and NO 2 The sensor (5) comprises an outer layer pipeline and an inner layer pipeline, the oxidation catalyst (15) is arranged in the outer layer pipeline, the second electronic control valve (16) is arranged in the middle of the inner layer pipeline, and the opening of the second electronic control valve (16) is formed by the NO sensor (4) and NO 2 The sensor (5) transmits back the control signal of the control unit (13) to determine, by adjusting the gas quantity of the inner and outer pipelines, the NO/NO 2 Ratio maintenance 1: 1.
5. The rapid removal of marine engine NO according to claim 1 X Is characterized in that: the gases are mixed in the hollow part of the device and enter the reduction catalyst (22) along the radial direction of the selective catalytic reduction device (10); NO, NO 2 With NH 3 The rapid SCR reaction occurs in the pore canal inside the reduction catalyst (22), so that NO in the ship tail gas is effectively removed X 。
6. Quick release marine engine NO according to claim 1 or 5 X Is characterized in that: the selective catalytic reduction device (10) comprises a shell (17), a backflow prevention plate (18), an air inlet channel (19), a first sealing baffle (20), an exhaust channel (21), a reduction catalyst (22), an isolation net (23) and a second sealing baffle (24), wherein the backflow prevention plate (18) and the second sealing baffle (24) are respectively arranged in the selective catalytic reduction device (10) transversely front and back, a columnar isolation net (23) is axially arranged in the middle, the air inlet channel (19) is arranged in the columnar isolation net (23), and the reduction catalyst (22) is placed on the periphery of the columnar isolation net (23).
7. The rapid removal marine engine NO of claim 6 X Is characterized in that: a cavity is formed between the reduction catalyst (22) and the shell (17) to form an exhaust passage (21), a first sealing baffle plate (20) is arranged at the front end of the exhaust passage (21), the ship tail gas radially flows through the reduction catalyst (22) and then enters the exhaust passage (21), and the selective catalytic reaction is carried outThe conical pipes at the outlet end of the original device (10) are converged, and finally the tail gas is discharged to the atmosphere from a tail gas outlet.
8. The rapid removal marine engine NO of claim 7 X Is characterized in that: the outlet end of the selective catalytic reduction device (10) is provided with NO X Sensor (11) and NH 3 Sensor (12), NO X Sensor (11) and NH 3 The sensor (12) transmits the detection signal to the control unit (13), and the opening of the first electronic control valve (8) is regulated by the control unit (13) to regulate the injection amount of urea.
9. A rapid removal of marine engine NO as claimed in any one of claims 1 to 8 X The method for denitration by the radial denitration device is characterized by comprising the following steps of: the method specifically comprises the following steps:
step 1: the tail gas of the ship enters SO 2 In the absorption device (2), in SO 2 Small amount of SO in the tail gas of the ship is absorbed under the action of the absorbent 2 Removing;
step 2: the ship tail gas enters a NO pre-oxidation device (3), and partial NO in the ship tail gas is oxidized into NO through a pre-oxidation catalyst (15) 2 An NO sensor (4) and NO are arranged at the outlet end of the NO pre-oxidation device (3) 2 A sensor (5) for sending the concentration signal to a control unit (13) to calculate NO/NO 2 By comparing the set value, outputting an electric signal to adjust the opening of a second electronic control valve (16) in the NO pre-oxidation device (3), and adjusting the gas bypass quantity to realize the NO and NO 2 Regulation of the ratio to make NO/NO 2 The ratio is controlled to be 1:1;
step 3: the pre-oxidized ship tail gas is led to a selective catalytic reduction device (10) through an exhaust pipe, in the exhaust pipe, the tail gas is mixed with urea spray sprayed by a urea spraying device (7), and the urea aqueous solution is decomposed to generate NH under the action of high temperature 3 ；
Step 4: the mixed ship tail gas enters a selective catalytic reduction device (10), and the mixed tail gas enters a selective catalytic reduction device (10) in the radial direction to selectively returnThe original catalyst carries out rapid SCR reaction, NO in ship tail gas X Is catalytically reduced to N 2 ；
Step 5: NO at the outlet end of a selective catalytic reduction device (10) X Sensor (11) and NH 3 The sensor (12) detects the processed ship tail gas, the measured value is sent to the control unit (13), and then the control unit (13) adjusts the first electronic control valve (8) to control the spraying amount of urea so as to lead NO X The final emissions meet regulatory requirements.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310184451.4A CN116392963A (en) | 2023-03-01 | 2023-03-01 | Quick removal of NO from ship engine X Radial denitration device and denitration method of (2) |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310184451.4A CN116392963A (en) | 2023-03-01 | 2023-03-01 | Quick removal of NO from ship engine X Radial denitration device and denitration method of (2) |
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| CN202310184451.4A Pending CN116392963A (en) | 2023-03-01 | 2023-03-01 | Quick removal of NO from ship engine X Radial denitration device and denitration method of (2) |
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