KR102360435B1 - Apparatus for exhaust gas purification and exhaust gas purification method - Google Patents

Abstract

The present invention is located at the front end of the exhaust gas exhaust pipe connected to the diesel engine, the first processing unit for injecting a mixed reducing agent to the exhaust gas; and a second processing unit located at the rear end of the discharge pipe and having a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate; It relates to an exhaust gas purification apparatus comprising a, and an exhaust gas purification method using the same. Through this, the present invention has excellent nitrogen oxide and particulate matter removal efficiency in a wide temperature range, and can remove soot while omitting an external heat source. A purification method may be provided.

Description

Exhaust gas purification device and exhaust gas purification method

The present invention relates to an exhaust gas purification apparatus and an exhaust gas purification method.

Diesel power generation is a method of generating electricity using energy generated by a diesel engine. A diesel engine is a type of internal combustion engine that compresses air in a cylinder to a high temperature and high pressure state, and then converts thermal expansion energy generated by injecting liquid fuel into mechanical motion. Since this process is performed by a combustion reaction at high temperature and high pressure, the diesel engine generates harmful substances such as nitrogen oxides (NOx) and particulate matter (PM).

Nitrogen oxides include nitrogen monoxide, nitrogen dioxide and other nitrogen oxides, and when they react with moisture in the atmosphere, they cause acid rain. In addition, nitrogen oxide itself may act on the human body and cause respiratory diseases such as emphysema and bronchitis.

Exhaust using the SNCR method using a reducing agent for Selective Non-Catalytic Reduction (SNCR) or the SCR method using a catalyst for Selective Catalytic Reduction (SCR) to treat such nitrogen oxides A gas purifier is used. The SNCR type or SCR type exhaust gas purification device is installed in an exhaust pipe connected to a diesel engine to reduce nitrogen oxides in exhaust gas.

The SNCR method has a characteristic that the treatment efficiency varies depending on the type of reducing agent. As a reducing agent, ammonia and urea are mainly used. In general, ammonia shows higher efficiency than urea, but urea, which is easy to store and handle, is often used. However, the conventional SNCR method has a low denitrification efficiency, so that an excessive amount of reducing agent is added. In this case, the required amount of reducing agent is high, which causes an increase in operating costs, and due to the excessive amount of reducing agent, a large amount of ammonia damages the boiler tube and generates ammonium sulfate in the air preheater, which can cause frequent corrosion and clogging of the thermal element.

The SCR method is excellent in nitrogen oxide reduction efficiency by using a catalyst specific to nitrogen oxide, but there is a difficulty in maintaining the temperature of the exhaust gas at an appropriate level. For example, when operating below the catalyst activation temperature, ammonia and sulfur oxides (SOx) in the exhaust gas form ammonium sulfate, which may poison the catalyst or cause clogging of the catalyst or air preheater. During operation, nitrogen oxide removal activity may be reduced and hydrothermal stability may be lowered.

One object of the present invention is to purify exhaust gas with excellent nitrogen oxide and particulate matter removal efficiency, a wide activation temperature range, and soot removal while omitting an external heat source, so that the facility is simple and the purification efficiency and economical efficiency are excellent It is to provide an apparatus and an exhaust gas purification method.

One embodiment of the present invention is located at the front end of the exhaust gas exhaust pipe connected to the diesel engine, the first processing unit to reduce the injection of a mixed reducing agent to the exhaust gas; and a second processing unit located at the rear end of the discharge pipe and having a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate; It relates to an exhaust gas purification device comprising a.

The mixed reducing agent may include 70% to 85% by weight of a urea solution, 10% to 20% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid.

The front end of the exhaust pipe may be a high temperature region in which the temperature of the exhaust gas is 600° C. to 850° C., and a molar ratio of nitrogen oxide to urea in the high temperature region may be 1:1 to 1:1.2.

The rear end of the exhaust pipe may be a mid-low temperature region in which the temperature of the exhaust gas is 200° C. to 550° C., and a molar ratio of nitrogen oxide to urea in the mid-low temperature region may be 1:0.7 to 1:0.9.

The base material of the diesel particulate filter is one or more of cordierite, silicon carbide, acicular mullite, aluminum titanate and alloy foam. It includes, and may have an average pore size of 10 μm to 30 μm, and a honeycomb structure.

The catalyst for the selective catalytic reduction is one in which copper (Cu) or iron (Fe) is ion-exchanged on the surface of a support, and the support may include at least one of mordenite, beta-zeolite, and ZSM-5.

The catalyst for selective catalytic reduction may include copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%.

The exhaust gas purification device may further include a regeneration device that is installed in a diesel engine, and instantaneously increases the temperature of the exhaust gas by directly injecting fuel into the diesel engine to instantly burn the diesel engine to regenerate the diesel particulate filter. .

Another embodiment of the present invention includes a first treatment step of reducing nitrogen oxides by injecting a mixed reducing agent into the exhaust gas at the front end of an exhaust gas exhaust pipe connected to a diesel engine; and a second treatment step of reducing nitrogen oxides and particulate matter by using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate at the rear end of the discharge pipe; It relates to an exhaust gas purification method comprising a.

In the exhaust gas purification method, the mixed reducing agent is 70 wt% to 85 wt% of a urea solution, 10 wt% to 20 wt% alcohol, 2.5 wt% to 5 wt% polyethylene glycol, and 2.5 wt% to 5 wt% alkylbencenesulfonic acid It may include mixing to include.

The first treatment step may include controlling the molar ratio of nitrogen oxides:urea to 1:1 to 1:1.2 in a high temperature region where the temperature of the exhaust gas is 600°C to 850°C.

The second treatment step may include controlling the molar ratio of nitrogen oxide to urea to be 1:0.7 to 1:0.9 in a mid-low temperature region where the temperature of the exhaust gas is 200°C to 550°C.

In the exhaust gas purification method, the base material of the diesel particulate filter is cordierite, silicon carbide, acicular mullite, aluminum titanate, and alloy foam. ), has an average pore size of 10 μm to 30 μm, and may have a honeycomb structure.

In the exhaust gas purification method, the catalyst for selective catalytic reduction is one in which copper (Cu) or iron (Fe) is ion-exchanged on the surface of a carrier, and the carrier is one or more of mordenite, beta-zeolite and ZSM-5. may include

In the exhaust gas purification method, the catalyst for selective catalytic reduction may include copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%.

The exhaust gas purification method may further include a third treatment step of regenerating the diesel particulate filter by instantaneously increasing the temperature of the exhaust gas by directly injecting liquid fuel into the diesel engine to instantaneously burn it.

The third treatment step may be to burn soot of the diesel particulate filter by instantaneously increasing the exhaust gas temperature at the rear end of the discharge pipe to 600° C. to 650° C. through instantaneous combustion.

The present invention has excellent removal efficiency of nitrogen oxides and particulate matter in a wide temperature range, a wide active temperature range, and can remove soot while omitting an external heat source. A device and an exhaust gas purification method may be provided.

1 is a view showing an exhaust gas purification apparatus according to an embodiment of the present invention.

One embodiment of the present invention is located at the front end of the exhaust gas exhaust pipe connected to the diesel engine, the first processing unit for injecting a mixed reducing agent to the exhaust gas; and a second processing unit located at the rear end of the discharge pipe and using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate; It relates to an exhaust gas purification device comprising a.

The exhaust gas purification apparatus of this embodiment has excellent nitrogen oxide and particulate matter removal efficiency, has a wide temperature range with excellent nitrogen oxide and particulate matter removal activity, and can remove soot while omitting an external heat source, so that the facility It is simple, and at the same time, it has excellent purification efficiency and economical efficiency.

Hereinafter, the present invention will be described in more detail with reference to FIG. 1 showing an exhaust gas purification apparatus according to an embodiment of the present invention.

The exhaust gas purification device of an embodiment is connected to the diesel engine 100 and installed in the exhaust pipe 200 for discharging exhaust gas generated from the diesel engine 100 to remove nitrogen oxides and particulate matter. In the diesel engine 100 , external air is introduced and combusted together with fuel, and exhaust gas including nitrogen oxides and particulate matter generated by the combustion is discharged through the exhaust pipe 200 . Exhaust gas passes through the exhaust gas purification apparatus of an embodiment including the first processing unit 21 and the second processing unit 22 in the process of passing through the discharge pipe 200, and is discharged in a reduced state of nitrogen oxides and particulate matter do.

Specifically, the discharge pipe 200 is located at the front end of the exhaust pipe connected to the diesel engine, the first processing unit 21 for reducing nitrogen oxide by injecting a mixed reducing agent to the exhaust gas; and a second processing unit 22 located at the rear end of the discharge pipe and reducing nitrogen oxides and particulate matter by using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate.

The first processing unit 21 serves to chemically reduce nitrogen oxides by directly injecting a mixed reducing agent into the exhaust gas, and to capture some scattered particles.

The mixed reducing agent may include 70% to 85% by weight of a urea solution, 10% to 20% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid. In this case, the nitrogen oxide reduction effect at the exhaust gas temperature of the first processing unit may be more excellent. In addition, the mixed reducing agent of the above formulation is easy to store, handle and manage, and it is possible to reduce the consumption of the reducing agent due to the high nitrogen oxide reduction efficiency, thereby preventing damage to the device due to the excessive amount of the reducing agent.

In one embodiment, the mixed reducing agent comprises 80% to 85% by weight of urea solution, 10% to 15% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid. may include In this case, nitrogen oxide in the initial exhaust gas can be reduced by 70 wt% or more, and the nitrogen oxide reduction efficiency is very good.

The front end of the discharge pipe 200 may be a high temperature region in which the temperature of the exhaust gas is 600°C to 850°C. In this case, the efficiency of reducing the exhaust gas in the first processing unit of the mixed reducing agent may be more excellent. In addition, when the mixed reducing agent of the above-mentioned formulation is used, nitrogen oxides can be removed with high efficiency in a wider high temperature range (600°C to 850°C).

In one embodiment, the temperature of the exhaust gas at the front end of the discharge pipe 200 may be 700°C to 800°C. Within the above range, when the aforementioned mixed reducing agent is used, the effect of reducing nitrogen oxides in the first processing unit can be further improved.

The second processing unit 22 removes nitrogen oxides in a selective catalytic reduction method using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate, and at the same time filters and removes particulate matter. Through this, it is possible to improve the nitrogen oxide reduction effect to 90% or more, and at the same time to remove the particulate matter.

The rear end 200 of the discharge pipe may be a low-mid temperature region in which the temperature of the exhaust gas is 200°C to 550°C. Within the above range, the effect of reducing nitrogen oxides by the second processing unit including the catalyst for selective catalytic reduction may be further improved.

The diesel particulate filter in which the catalyst for selective catalytic reduction is coated on a substrate performs chemical removal of nitrogen oxides using a catalyst for selective catalytic reduction, and at the same time physically removes particulate matter and soot using a particulate filter carry out

The base material of the diesel particulate filter is cordierite (cordierite, Cd, 2MgO·2Al ₂ O ₃ ·5SiO ₂ ), silicon carbide (SiC), acicular mullite (acicular mullite, ACM, Al ₂ SiO ₅ ), aluminum titanate (Aluminum titanate, AT, Al ₂ TiO ₅ ), and alloy foam (alloy foam) may be included. In this case, the diesel particulate filter may be excellent in the effect of removing particulate matter, as well as excellent in hydrothermal stability. In addition, by implementing excellent heat resistance at an instantaneous high temperature, it is not damaged by a method of instantaneously raising the temperature of the exhaust gas as described later, and regeneration is possible.

The base material of the diesel particulate filter may have an average pore size of 10 μm to 30 μm and have a honeycomb structure. In this case, not only the removal effect of particulate matter is more excellent, but also the purification efficiency can be further improved by increasing the contact area between the catalyst for selective catalytic reduction and the exhaust gas. In addition, when the average pore size is within the above range, even when the catalyst for selective catalytic reduction is coated on the surface of the substrate, the pressure drop does not occur in the exhaust gas purification device, so that the exhaust efficiency may be more excellent.

The catalyst for selective catalytic reduction is one in which copper (Cu) or iron (Fe) is ion-exchanged on the surface of a support, and the support may include at least one of mordenite, beta-zeolite, and ZSM-5. Within the above range, not only the hydrothermal stability of the catalyst is excellent, but also the removal efficiency for nitrogen oxides can be further improved. In particular, excellent catalytic activity can be maintained even when the diesel particulate filter is regenerated by a method of instantaneously increasing the temperature of the exhaust gas as described later by implementing excellent heat resistance at an instantaneous high temperature.

The catalyst for selective catalytic reduction may include copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%. Within the above range, the removal efficiency for nitrogen oxides may be further improved. For example, the catalyst for the selective catalytic reduction is 15 wt% to 35 wt%, 20 wt% to 35 wt%, 20 wt% to 30 wt% eh of copper (Cu) or iron (Fe) 25 wt% to It may be included in 35% by weight. In the above range, the removal efficiency for nitrogen oxides can be further improved, and the pressure drop occurrence rate is low, so that the exhaust efficiency can be further improved.

In one embodiment, the catalyst for selective catalytic reduction is, for example, after the above-described carrier is added to an ion exchange solution containing copper (Cu) or iron (Fe), room temperature (eg, 20 ° C.) or higher It may be prepared by stirring at a temperature. The catalyst for selective catalytic reduction on which the ion exchange has been completed may be washed with deionized water using a vacuum filter and coated on the base material of the diesel particulate filter. The substrate of the diesel particulate filter coated with the catalyst for selective catalytic reduction as described above is dried at a temperature of 110°C to 120°C in a dryer for 20 to 24 hours, and then calcined at about 400°C to about 600°C. can

Although not shown in the drawing, the exhaust gas purification device is installed in a diesel engine, and by directly injecting fuel into the diesel engine to instantaneously burn it, a regeneration device for regenerating the diesel particulate filter by increasing the temperature of the exhaust gas instantaneously is added. can be included as Such a regeneration device may directly inject fuel into a cylinder after a power stroke by using a fuel injection device of a diesel engine. In this case, the temperature of the exhaust gas of the second processing unit may be instantaneously increased to 600°C to 650°C. Through this, it is possible to easily regenerate the diesel particulate filter by burning soot accumulated in the diesel particulate filter. Such an exhaust gas purification device can omit an external heat source device such as a burner used to burn and regenerate a conventional diesel particulate filter, so it is economical in terms of facilities and nitrogen oxides generated during combustion for regeneration. and combustion particles, etc., can be prevented in advance, so the efficiency is excellent.

The exhaust gas purification device is a conventional filter through the complex action of a second processing unit using a diesel particulate filter coated with a catalyst for selective catalytic reduction and a regeneration device that regenerates the filter by directly injecting fuel into the diesel engine. There is an advantage in that the DOC device installed at the front end of the diesel particulate filter can be omitted. In this case, it is possible to further reduce the occurrence rate of pressure drop in the exhaust gas purification device to improve the exhaust efficiency, and to increase the efficiency while reducing the equipment more simply.

In addition, the exhaust gas purification apparatus includes the first and second processing units described above; Alternatively, through the combined action of the first processing unit, the second processing unit, and the third processing unit, 70% by weight or more of nitrogen oxides can be removed from the front end of the discharge pipe, and 90% by weight or more of nitrogen oxides can be finally reduced, and at the same time At least 90% by weight or 100% of particulate matter can be removed.

Another embodiment of the present invention includes a first treatment step of reducing nitrogen oxides by injecting a mixed reducing agent into the exhaust gas at the front end of an exhaust gas exhaust pipe connected to a diesel engine; and a second treatment step of reducing nitrogen oxides and particulate matter by using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate at the rear end of the discharge pipe; It relates to an exhaust gas purification method comprising a.

This exhaust gas purification method may be performed through the exhaust gas purification apparatus of the above-described embodiment.

The first processing step may be performed in the above-described first processing unit 21 . In the first treatment step, a mixed reducing agent is directly injected into the exhaust gas passing through the first treatment unit to chemically reduce nitrogen oxides, and at the same time capture some scattered particles.

In the first treatment step of the exhaust gas purification method, the mixed reducing agent is 70 wt% to 85 wt% of a urea solution, 10 wt% to 20 wt% alcohol, 2.5 wt% to 5 wt% polyethylene glycol, and 2.5 wt% alkylbenzenesulfonic acid % to 5% by weight may include mixing. In this case, the nitrogen oxide reduction effect at the exhaust gas temperature of the first processing unit may be more excellent. In addition, the mixed reducing agent of the above formulation is easy to store, handle and manage, and it is possible to reduce the consumption of the reducing agent due to the high nitrogen oxide reduction efficiency, thereby preventing damage to the device due to the excessive amount of the reducing agent.

In one embodiment, the first treatment step is 80% to 85% by weight of urea solution, 10% to 15% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid % may include using a mixed reducing agent prepared by mixing. In this case, nitrogen oxide in the initial exhaust gas can be reduced by 70 wt% or more, and the nitrogen oxide reduction efficiency is very good.

The second processing step may be performed in the above-described second processing unit 22 . In the second treatment step, nitrogen oxides are removed by selective catalytic reduction using a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate, and particulate matter is removed by filtration. Through this, it is possible to improve the nitrogen oxide reduction effect to 90% or more, and at the same time to remove the particulate matter.

In the exhaust gas purification method, the base material of the diesel particulate filter is cordierite, silicon carbide, acicular mullite, aluminum titanate, and alloy foam. ), an average pore size of 10 μm to 30 μm, and may have a honeycomb structure. In this case, the diesel particulate filter may be excellent in the effect of removing particulate matter, as well as excellent in hydrothermal stability. In addition, by implementing excellent heat resistance at an instantaneous high temperature, it is not damaged by a method of instantaneously raising the temperature of the exhaust gas as described later, and regeneration is possible.

In the exhaust gas purification method, the catalyst for selective catalytic reduction is one in which copper (Cu) or iron (Fe) is ion-exchanged on the surface of a carrier, and the carrier is one or more of mordenite, beta-zeolite and ZSM-5. may include In this case, not only the hydrothermal stability of the catalyst is excellent, but also the removal efficiency for nitrogen oxides can be further improved. In particular, excellent catalytic activity can be maintained even when the diesel particulate filter is regenerated by a method of instantaneously increasing the temperature of the exhaust gas as described later by implementing excellent heat resistance at an instantaneous high temperature.

In the exhaust gas purification method, the catalyst for selective catalytic reduction may include copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%. Within the above range, the removal efficiency for nitrogen oxides may be further improved. For example, the catalyst for the selective catalytic reduction is 15 wt% to 35 wt%, 20 wt% to 35 wt%, 20 wt% to 30 wt%, or 25 wt% to 35 wt% of copper (Cu) or iron (Fe) It may be included in weight %. In the above range, the removal efficiency for nitrogen oxides can be further improved, and the pressure drop occurrence rate is low, so that the exhaust efficiency can be further improved.

The exhaust gas purification method may further include a third treatment step of regenerating the diesel particulate filter by instantaneously increasing the temperature of the exhaust gas by directly injecting liquid fuel into the diesel engine to instantaneously burn it.

The third treatment step may be to burn soot of the diesel particulate filter by instantaneously increasing the exhaust gas temperature at the rear end of the discharge pipe to 600° C. to 650° C. through instantaneous combustion.

This third processing step may be performed through a regeneration device installed in the diesel engine, and the regeneration device may directly inject fuel into the cylinder after the power stroke by using the fuel injection device. In this case, the temperature of the exhaust gas of the second processing unit may be instantaneously increased to 600°C to 650°C. Through this, it is possible to easily regenerate the diesel particulate filter by burning soot accumulated in the diesel particulate filter. This method can omit an external heat source device such as a burner used to burn and regenerate the conventional diesel particulate filter, so it is economical in terms of facilities, and nitrogen oxides and combustion particles generated during combustion for regeneration. It can be prevented in advance, so it is more efficient.

The exhaust gas purification method is through the combined action of a second treatment step of using a diesel particulate filter coated with a catalyst for selective catalytic reduction and a third treatment step of regenerating the filter by directly injecting fuel into the diesel engine. , there is an advantage that the DOC device installed at the front end of the conventional diesel particulate filter can be omitted. In this case, it is possible to further reduce the occurrence rate of pressure drop in the exhaust gas purification device to improve the exhaust efficiency, and to increase the efficiency while reducing the equipment more simply.

In addition, the exhaust gas purification method includes the first and second treatment steps described above; Alternatively, through the combined action of the first treatment step, the second treatment step, and the third treatment step, it is possible to remove at least 70% by weight of nitrogen oxides from the front end of the discharge pipe, and finally, it is possible to reduce nitrogen oxides by more than 90% by weight and at the same time, it is possible to remove 90% by weight or more or 100% of particulate matter.

Example

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, these are provided only to explain the present invention in detail, and the scope of the present invention is not limited thereto.

production example 1 to 5: Preparation of mixed reducing agent

A mixed reducing agent was prepared by mixing urea, alcohol, polyethylene glycol and alkyl benzenesulfonic acid according to the composition ratio shown in Table 1 below. (At this time, 30% concentrated urea was used)

production example Element
(weight%) Alcohol
(weight%) polyethylene glycol
(weight%) Alkylbenzenesulfonic acid
(weight%) Preparation Example 1 70 20 5 5 Preparation 2 75 20 2.5 2.5 Preparation 3 80 15 2.5 2.5 Preparation 4 85 10 2.5 2.5 Preparation 5 100 0 0 0

Example 1 to 4

In order to prepare a catalyst for selective catalytic reduction, ZSM-5 was added to Cu(NO ₃ ) ₂ , followed by ion exchange while stirring at a temperature above room temperature. After the ion exchange was completed, the catalyst was cleaned by supplying deionized water from a reduced pressure filtration device with a filter, and coated on Cordierite DPF. Then, the catalyst-coated Cordierite DPF was put in a dryer and dried at a temperature of 110° C. to 120° C. for 24 hours. After drying, the completed sample was calcined at about 500° C. for several hours to prepare a diesel particulate filter coated with a catalyst for selective catalytic reduction. At this time, the amount of copper supported on the catalyst was controlled as shown in Table 2 below.

The diesel generator operating in the island area was equipped with an exhaust gas purification device by installing a mixed reducing agent injection facility, a diesel particulate filter coated with the catalyst for selective catalytic reduction prepared above, and a control facility.

In the exhaust gas purification device, the exhaust gas (nitrogen oxide 1000ppm, PM 5mg/ ^{m 3 ,} oxygen 13.0%, moisture 11 %, carbon monoxide, etc.) was injected, and the mixed reducing agent of Preparation Examples 1 to 4 was sprayed as shown in Table 2 from the front end of the discharge pipe to perform the first step treatment. After that, the exhaust gas (500 ℃) treated in the first step is passed through the rear end of the exhaust pipe installed with a diesel particulate filter coated with a catalyst for selective catalytic reduction to be treated in the second step, and an operation test for about 1,000 hours is performed. did

Whether a diesel particulate filter coated with a catalyst for selective catalytic reduction is used mixed reducing agent Cu
(weight%) Example 1 ○ Preparation Example 1 15 Example 2 ○ Preparation 2 20 Example 3 ○ Preparation 3 25 Example 4 ○ Preparation 4 30

comparative example One

A single reducing agent injection facility and a general diesel particulate filter that is not coated with a catalyst for selective catalytic reduction and a control facility were installed in the diesel generator operating in the island area to provide an exhaust gas purification device.

In the exhaust gas purification device, the exhaust gas (nitrogen oxide 1000ppm, PM 5mg/ ^{m 3 ,} oxygen 13.0%, moisture 11 %, carbon monoxide 100ppm, etc.) was injected, and the mixed reducing agent of Preparation Example 5 was sprayed as shown in Table 3 to perform the first step treatment. Thereafter, the exhaust gas (500° C.) treated in the first step was passed through the rear end of the exhaust pipe separately installed with a selective catalytic reduction device and a diesel particulate filter, and an operation test was performed for about 1,000 hours.

Whether a diesel particulate filter coated with a catalyst for selective catalytic reduction is used mixed reducing agent Cu
(weight%) Comparative Example 1 × Preparation 5 15

<Evaluation of initial nitrogen oxide removal rate>

The nitrogen oxide removal rates of each of the mixed reducing agents used in Examples 1 to 4 and Comparative Example 1 were evaluated and shown in Table 4.

In an exhaust gas purification device equipped with a reducing agent injection device, the mixed reducing agent used in Examples 1 to 4 and Comparative Example 1 was sprayed at reaction temperatures of 500°C, 600°C, 700°C and 800°C. At this time, the exhaust gas had a reaction temperature of about 4,000 Nm ³ /h at 600° C. to 850° C., and a nitrogen oxide:urea molar ratio of 1:2.4 (nitrogen oxide 1000 ppm, PM 5 mg/m ³ , oxygen 13.0%, moisture 11%, carbon monoxide 100 ppm etc).

The concentration of the nitrogen oxide was measured using a measuring instrument using a non-dispersive infrared method.

Nitrogen oxide removal rate (%) mixed reducing agent 500℃ 600℃ 700℃ 800℃ Example 1 Preparation Example 1 40 55 75 80 Example 2 Preparation 2 55 68 77 79 Example 3 Preparation 3 55 68 78 80 Example 4 Preparation 4 40 65 75 85 Comparative Example 1 Preparation 5 20 30 40 47

<Evaluation of final nitrogen oxide removal rate and particulate matter removal rate>

With respect to the exhaust gas purification methods carried out in Examples 1 to 4 and Comparative Example 1, the nitrogen oxide concentration and particulate particle concentration of the exhaust gas finally discharged were measured to evaluate the nitrogen oxide removal rate and particulate particulate removal rate. The results are shown in Table 5.

Example reducing agent Whether a diesel particulate filter coated with a catalyst for selective catalytic reduction is used nitrogen oxide
Removal rate (%) particulate matter
Removal rate (%) Example 1 Preparation Example 1 ○ 90 100 Example 2 Preparation 2 ○ 93 100 Example 3 Preparation 3 ○ 97 100 Example 4 Preparation 4 ○ 97 100 Comparative Example 1 Preparation 5 × 80 80

100: diesel engine
200: discharge pipe
21: first processing unit
22: second processing unit

Claims (17)

a first processing unit located at the front end of the exhaust gas exhaust pipe connected to the diesel engine and injecting a mixed reducing agent into the exhaust gas; and
A second processing unit located at the rear end of the discharge pipe and provided with a diesel particulate filter coated with a catalyst for selective catalytic reduction on a substrate;
The mixed reducing agent comprises 70% to 85% by weight of urea solution, 10% to 20% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid exhaust gas purification device.
delete delete delete According to claim 1,
The base material of the diesel particulate filter is cordierite (cordierite), silicon carbide (silicon carbide), acicular mullite (acicular mullite), aluminum titanate (aluminum titanate) and at least one of alloy foam (alloy foam) that includes,
An exhaust gas purification device having an average pore size of 10 μm to 30 μm and a honeycomb structure.
According to claim 1,
The catalyst for the selective catalytic reduction is copper (Cu) or iron (Fe) ion-exchanged on the surface of the carrier,
The carrier is an exhaust gas purification device comprising at least one of mordenite, beta-zeolite, and ZSM-5.
7. The method of claim 6,
The catalyst for the selective catalytic reduction is an exhaust gas purification device comprising copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%.
According to claim 1,
The exhaust gas purification device is installed in the diesel engine, and by directly injecting fuel to the diesel engine and instantaneous combustion, to increase the temperature of the exhaust gas instantaneously to further include a regeneration device for regenerating the diesel particulate filter exhaust gas purification system.
a first processing step of reducing nitrogen oxides by injecting a mixed reducing agent into the exhaust gas at the front end of the exhaust gas exhaust pipe connected to the diesel engine; and
A second treatment step of reducing nitrogen oxides and particulate matter by using a diesel particulate filter in which a catalyst for selective catalytic reduction is coated on a substrate at the rear end of the discharge pipe;
The mixed reducing agent is a mixture of 70% to 85% by weight of urea solution, 10% to 20% by weight of alcohol, 2.5% to 5% by weight of polyethylene glycol, and 2.5% to 5% by weight of alkylbenzenesulfonic acid How to purify exhaust gas.
delete delete delete 10. The method of claim 9,
The base material of the diesel particulate filter is cordierite (cordierite), silicon carbide (silicon carbide), acicular mullite (acicular mullite), aluminum titanate (aluminum titanate) and at least one of alloy foam (alloy foam) that includes,
An exhaust gas purification method having an average pore size of 10 μm to 30 μm and a honeycomb structure.
10. The method of claim 9,
The catalyst for the selective catalytic reduction is copper (Cu) or iron (Fe) ion-exchanged on the surface of the carrier,
The carrier is an exhaust gas purification method comprising at least one of mordenite, beta-zeolite, and ZSM-5.
15. The method of claim 14,
The catalyst for selective catalytic reduction is an exhaust gas purification method comprising copper (Cu) or iron (Fe) in an amount of 15 wt% to 35 wt%.
10. The method of claim 9,
The exhaust gas purification method further comprises a third processing step of regenerating the diesel particulate filter by instantaneously increasing the temperature of the exhaust gas by directly injecting liquid fuel into the diesel engine and instantaneous combustion, thereby regenerating the diesel particulate filter. .
17. The method of claim 16,
The third treatment step is to burn the soot of the diesel particulate filter by instantaneously raising the exhaust gas temperature at the rear end of the exhaust pipe to 600° C. to 650° C. through instantaneous combustion.

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