TWI342358B - Exhaust gas purifying device for diesel engine - Google Patents

Description

1342358 IX. Description of the Invention: [Technical Field] The present invention relates to an exhaust gas purifying apparatus for a diesel engine, which can effectively purify nitrogen oxides 5 (N0X) and particulate matter (PM) contained in exhaust gas of a diesel engine ). [Prior Art]

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The demand for diesel engines has continued to increase because diesel engines can be used in a wide range of industries, such as automobiles, shipbuilding, general industry, etc., and can be energized with high fuel efficiency and high reliability. Operate at high load. In addition, the use of diesel engines is obvious for the 3L car plan or super car plan proposed for the high fuel efficiency of automobiles, so it is expected that diesel engines will be added to automobiles. However, diesel cars should be responsible for 40% of air pollution and, therefore, are considered to be the main culprit in air pollution in developed countries. In order to cope with the above problems, countries have strengthened regulations on exhaust gas for diesel vehicles. Air pollution caused by diesel vehicles is mainly caused by nitrogen oxides (NOx) and particulate matter (pM). Therefore, the main target material in the exhaust gas regulations of diesel vehicles is that nitrogen oxides and particulate matter are used to treat the above substances, all of which focus on reducing nitrogen oxides by delaying fuel injection timing and exhaust gas recirculation (EGR). Concentrated and reduced particulate matter by enhancing and reforming the engine's combustion efficiency. A method for reducing nitrogen oxides is to use a selective catalyst to restore the gas oxides to nitrogen and oxygen using a reducing agent on the catalyst. Gas, urea and carbon argon compounds can be used as a disadvantage of the additional supply of ammonia and urea (4). (4) Hydrocarbons are better. "The types of hydrocarbons are diesel, kerosene, _, propylene, B. Women, Ding Fu, Jia Xuan, etc.

10 At the same time, diesel particulate filters are widely used to remove pM, and regeneration methods can be classified into passive regenerative and active regenerative types. In the passive regeneration type, the diesel particulate filter is regenerated by converting N? into N?2 by an oxidation catalyst on the DPF and oxidizing the produced N?2 to PM. Moreover, in the active regeneration type, an auxiliary device is used to strongly increase the temperature of the filter to achieve more active regeneration. In the active regeneration type, the temperature of the fuel is increased by using an electric heater, and an electropolymer reactor disposed in front of the DPF, injection and combustion of the diesel fuel, and the like are used. '15

As a conventional exhaust gas purifying device for a diesel engine, there is known an exhaust gas purifying device in which a 'DPF with an oxidizing catalyst thereon is disposed upstream of an exhaust passage'. Hydrocarbon selective catalyst reduction type nitrogen oxidation A material reduction catalyst (DeNOx catalyst) is disposed downstream of the exhaust gas passage, and a fuel injector system is installed between the DPF and the DeNOx catalyst. 20 However, this conventional exhaust gas purifying apparatus is difficult to effectively remove nitrogen oxides, CO and total chlorocarbon compounds (THC) containing particulate matter in an intermediate temperature range. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a waste for use in a diesel engine. 6 1342358::Chemical device: wherein 'reducing the performance of nitrogen oxides and removing particulate matter, the efficiency is 250 S at the true temperature of the exhaust gas of the brakes. In the range of 600 ° C, it is more improved', and CQ, THC, etc. are removed. j and 'the other purpose of the present invention is to provide a kind of diesel engine for use in a gas purification device. The oxide catalyst and the diesel particulates are connected in series 5 and the 1 fuel injector is installed in the nitrogen. The front side of the oxide reduction catalyst 'by this, the reduction of nitrogen oxides can be carried out by a diesel fuel injector, and the diesel particulate filter is simultaneously regenerated. H-existing exhaust gas purification device for diesel engines can effectively purify nitrogen oxides (NOx) and particulate matter (PM) contained in the exhaust gas of diesel engines, and in particular, proposes exhaust gas purification in the exhaust passage of diesel engines. The apparatus, wherein a nitrogen oxide reduction catalyst portion for reducing nitrogen oxides and a diesel particulate filter for removing particulate matter are successively disposed from upstream of the exhaust gas flow, and a diesel fuel injector system is installed In front of the nitrogen oxide reduction catalyst portion. Hereinafter, the present invention will be described in detail. According to the present invention, an exhaust gas purifying apparatus for a diesel engine can reduce NOx on a nitrogen oxide reduction catalyst portion (hereinafter referred to as "DeN〇x catalyst portion") by injecting diesel fuel, and is removed by diesel combustion. The particulate matter accumulated in the diesel particulate filter (hereinafter referred to as "DPF") also removes C0 and THC. In the present invention, when the nitrogen oxide is removed by the DPF catalyst in an intermediate temperature range of 250 to 350 ° C and by the DeNOx catalyst, the nitrogen oxides can be more effectively removed. In the case where the conventional DeNOx catalyst 7 1342358 is conventionally used, the desired removal efficiency cannot be achieved because the transition rate in the intermediate temperature range of 250 to 350 °C is very low. Moreover, in the present invention, when the diesel fuel is injected in front of the DeN〇x catalyst, since most of the particulate matter is removed in the DPF portion, the 'diesel fuel is spread evenly while passing through the DeN〇x. Catalyst, therefore, regeneration of the DPF can be easily achieved. Further, the exhaust gas purifying apparatus according to the present invention can more effectively remove carbon monoxide (c〇) and total hydrocarbon (THC) removed in the conventional exhaust gas purifying apparatus. Since C〇 cannot be removed in the DeNOx catalyst, C0 will increase more in the case where the DeNOx catalyst is separately set. However, due to the platinum group element of the DPF catalyst in the present invention, c〇 is more effectively removed at temperatures exceeding 200 °C. In the case of THC, it is also not removed in the DeN〇x catalyst. In particular, when diesel fuel is injected as a reducing agent for removing nitrogen oxides, more hydrocarbons (HC) are contained in the exhaust gas than in the case of no injection. In order to solve such a problem, unreacted HC which is simultaneously increased by the DeN〇x catalyst can be effectively removed in the DpF catalyst. As an embodiment of the present invention, an exhaust gas purifying device is shown in Fig. 1. According to Fig. 1, the "DeNOx catalyst portion 1" is provided in the upstream JDPF portion 2 where the exhaust gas flows, and is disposed in series with it, and a diesel injector 3 is attached to the front side of the DeN x x catalyst portion. As another embodiment of the present invention, the exhaust gas purifying device is shown in Fig. 8 134.2358^. = According to the ® 2, the number of households DeN〇x is connected to each other and is continuously set in multiple layers. In the case where the medium is disposed adjacently, there is a point that increases the surface through which the exhaust gas passes, thereby enhancing the N0X reduction efficiency, and the reduction efficiency is better in different temperature ranges. 'Because the operating state of the engine will cause a difference in the reduction performance depending on the temperature of the exhaust gas, since the reduction efficiency can be increased by using different = catalyst or changing the catalyst content in each layer, regardless of the operation of the engine What is the status, Ν0Χ restore performance is also very good. The DeNOx catalyst unit contains a catalyst of a silver (Ag) component, a copper (Cu) component or a mixture thereof. Possible materials for the composition with silver (Ag) are selected from silver metal (Ag), silver oxide (Age), silver chloride (AgC1), silver nitride (AgN〇3), silver sulfide (AgaSO4) or A group of mixtures. A possible material for the copper (Cu) component is selected from the group consisting of copper metal (Cu), copper oxide, copper acetate, copper nitrate, copper sulfate or a mixture thereof. As the carrier for carrying the catalyst, alumina (manganese 2〇3), cerium oxide (Si〇2), titanium dioxide (Ti〇2), cerium oxide (Ce〇2), zirconia (Zr〇2) can be used. Or zeolite, it is also possible to pass two or more kinds of mixtures. In particular, in the case of using alumina as a carrier, the 'N0X reduction performance is more excellent. The carrier is used by coating on a support body, and the amount of coating is preferably from 0.5 to 4 g/in3, based on the total amount of the catalyst. In the case where the coating amount is less than 〇 5g/in3, the amount of the catalyst contained in the # is absolutely insufficient, and the performance of the catalyst is remarkably lowered. Conversely, in the case where the coating amount exceeds 4 g/in3, the performance of the catalyst does not increase any more and does not contribute to the production.

The support body of the DeNOx catalyst portion is a flow-through support body made of heat-resistant shunt or metal, and a special example thereof may be a cordierite bee structure body. Preferably, a silver component, a copper component or a mixture thereof in an amount of from 0" to 1% by weight is used depending on the weight of the carrier. In the case where the content of the component as a catalyst is less than 0.1% by weight, when the content is absolutely insufficient, the performance of the catalyst is remarkably lowered. Conversely, in the case where the content exceeds 1 liter by weight, the performance of the catalyst is remarkably lowered when the component exists in a metallic state and is not favorable for reduction. Moreover, the medium according to the present invention additionally carries a platinum group component, so that the nitrogen oxide reduction performance is more excellent in the temperature range of 25 to 6 〇〇〇c of the true temperature of the exhaust gas. The reduction catalyst has a characteristic that the nitrogen oxide reduction performance is excellent in the temperature range of the exhaust gas to a true temperature of 600 ° C, and in the case of a platinum group component in the range of 35 〇 to 45 〇 This performance will be even better within the scope of 〇c. The metal which can be used as the platinum group precious metal carried in the DeNOx catalyst portion may be one of Pt, Pd, RU, ruthenium and Rh, or at least a mixed species. As the starting material of the (pd), it is possible to use acid, palladium chloride, chlorotetramine palladium or the like. Further, as a starting material of platinum (Pt), chlorine 16 acid, diamine nitrite, and diamine gas acid scale can be used. Further, as the starting material of money (Rh), it is possible to use gasification money, money, hexachlorotriamine or the like. Further, the platinum group metal is preferably from 0.0001 to 0.5% by weight, and is from 0.0005 to 0.2% by weight, more preferably from 0.1 to 0.1% by weight. This is because if the content is less than 3421% by weight of 1342358, it does not contribute to the performance improvement, and if the content exceeds 5% by weight, the performance will drop rapidly. The DPF according to the present invention is a filter with a platinum group catalyst, and the element contained in the platinum group catalyst is at least one selected from the group consisting of Pt, Pd, Bu or Rh, preferably Pt or Pd. For the support coated by the carrier • In this case, the content of the platinum group catalyst carried in the DPF is 0.01 to 5 weight percent. The effect of removing particulate matter does not occur in less than 0.01 • Å. In the case of m, m can have an economic disadvantage, that is, in the case of more than 5% by weight, the performance can no longer be improved. Moreover, in addition to the platinum group catalyst, the DPF can carry an oxidation catalyst. . The oxidizing catalyst component can act to inhibit the oxygen or "T of the sulphurous acid gas to increase the surface activity of the turmeric catalyst. In general, the uranium-catalyst exhibits a high degree of heterogeneity in the oxidation of the organic/storage organic fraction (S0F); however, it leads to a disadvantage that is the 15 峨 product of the sulfur contained in the diesel fuel towel. When sulfite gas lang 02) is oxygen-like sulfate, 'particulate matter = 1 = increase in profit. In order to solve such a problem, at least one catalyst component selected from V, w or Mo may be used in addition to the platinum group catalyst. Preferably, the amount of the catalyst component of the at least one selected or M〇 is 0.01 to 2 weight percent. 1, i in the case of CKOi weight percentage, there is no effect of inhibiting the oxidation of the sub-body, and, in the content of more than 2% by weight, the shape is not obvious, and thus is not economical. Moreover, the alkali metal components such as μ A & , have a very low temperature mobility, and increase the surface activity of the platinum group catalyst due to the twinning effect, thereby promoting the contact of the 11 1342358 catalyst with the particulate matter (4). And thus enhance the catalytic activity. Preferably, the metal is used in an amount of from 0.01 to 1% by weight for the continuous body to which the rhyme is applied. In the case of a clear form having a content of less than 〇〇1 by weight, the effect of increasing the reactivity of the fine catalyst is not observed, and the effect is not obvious when the content exceeds 1% by weight, and thus the effect is not Economic benefits.

Ίο Moreover, as a carrier for carrying a catalyst, it is possible to use Oxidation (ΑΙΑ), O2 (2), Titanium Dioxide (Ti〇2), Cerium Oxide (5) 2), Oxidation (ZK) 2), or Sea Stone. 'You can also use more than two kinds of mixtures. The DPF according to the present invention can remove accumulated particulate matter by using an increase in the temperature of the exhaust gas and simultaneously using oxidation of the diesel fuel injected from the nitrogen oxides in front of the catalyst. Preferably, it can be used including cordierite, with '15

^ ^lC shouts, alloys such as alloys or FeCl" alloys, because these materials have a high resistance to recording, such as a support body, so they can be safely used even under mild conditions. In the case of using a high heat-resistance dpfaI* body, it has the advantage of being able to operate safely under the high heat generated by the capsule, and saves the injection by using the heat energy generated by excessive denier. The above and other objects, features and advantages of the present invention will be described in detail with reference to the accompanying drawings. The invention is not limited to the embodiments, but the invention includes all variations, modifications and equivalent substitutions within the spirit and scope of the claims. [Production Example 1] Nitrogen The manufacturing process of the oxide reduction catalyst is described as follows: γ alumina powder [surface area: 210 m 2 / gr, pore volume: 〇 5 cc / gr, specific gravity: 〇 8 g / cc] mixed with acetic acid and steamed water 'then' use The wet ball mill grinds the mixture for twenty-four hours, so that a uniform alumina slurry can be produced. The oxygen having an intermediate particle size is ground by a wet ball mill. The aluminum is 2 to 8 mm. The oxidized mud slurry prepared above is roughly coated with a cordierite honeycomb having a diameter of 1125 inches, a length of 3 inches, and a cell density of 4 inches. 〇cpsi, causing the amount of alumina to become 3g/m3, and then increasing from the normal temperature at a rate of 3Q per minute until the temperature reaches 子0. Then, in the coffee, drying for three hours, then from C Start to increase to 55〇Qc at a rate of 3〇c per minute, followed by calcination for three hours. $后' will be with indigo; 5 forging & oxidation 29 of the body is pushed into the dissolved chlorine The formed glutinous agent becomes a precursor of the ship and silver nitrate, so that the weight of the silver is 20% by weight, and the content of the platinum catalyst component is set to 〇〇〇1 by weight, and then Under the same conditions of the oxidizing coating layer, the dried body was at (10). [Aging for three hours, and then forging for three hours at 550 ° C. 1342358 [Production Example 2] The manufacturing process of the diesel particulate filter is as follows : 252 grams of polyvinyl pyrrolidin (polyvinyl pyrrolid〇ne) Manufactured by Aldrich Chemical Co., Ltd., with an average molecular weight of 10,000) dissolved in distilled water in a two liter flask to produce a homogeneous solution. 30. 4 grams of chlorinated acid and one liter of methanol are placed therein, and then Stirring. This solution was refluxed at 8 ° C for six hours, thus obtaining a dark brown platinum colloidal solution with a platinum weight of 0.62. 15.4 g of ammonium molybdate and 1 g of potassium hydroxide were placed in 250 mL respectively. The steaming water is then mixed to produce an aqueous solution of molybdenum and an aqueous solution of potassium. The prepared gelatinous solution, the aqueous solution of molybdenum and the aqueous solution of potassium are mixed in the same weight ratio, and thus, can be used for a catalytic filtration. A metal salt gel solution. As the support body of the catalytic filter, a wall flow ceramic filter manufactured by C〇ning Co., Ltd. having a diameter of 11.25 inches, a length of 14 inches, and a cell density of 2 〇〇 cpsi can be used. After precipitating 7 wt% of titanium dioxide mixed with a coating solution of cerium oxide, the monomer was dried and calcined. The gelled mixture for the catalyzed filter was carried into the coated support body, and the content of the support body coated according to the carrier was 0.27 weight percent, respectively, and 0.16 weight percent 'potassium 0.077 weight percent. . Then, after drying at 12 ° C for two hours, a diesel particulate filter can be produced by calcining at 550 ° C for four to six hours. [Example 1] Performance Evaluation of Exhaust Gas Purifying Apparatus - 14 1342358 The nitrogen oxide reduction catalyst produced in the manufacturing example 1 and the diesel particulate filter manufactured in the manufacturing example 2 were continuously connected, and then It is placed in a small metal container made of stainless steel. In order to carry out the evaluation test, a Daewoo engine was used with a displacement of 11 L and a turbocharger and intercooler were applied. Tests for evaluating the removal of nitrogen oxides and particulate matter were carried out in accordance with the D-13 mode designed for heavy duty diesel engines. This test was performed under selected steady state | engine operating conditions by fixing the engine ΓΡη and the load (torque) of the engine motor. The diesel used in this test was made of ultra-low sulfur diesel with a sulfur content of 50 ppm. The results showed a reduction ratio of 92% for carbon monoxide, 34% for hydrocarbons, 38% for oxynitride, and 93% for particulate matter. [Table 1] Test of nitrogen oxide reduction and particulate matter removal of Daewoo engine 15 Results .

[Embodiment 2] Performance evaluation of the exhaust gas purifying device 2 Here, the same exhaust gas purifying device as that of the first embodiment is used. The car used for the test and evaluation was produced by Japan HINO Co., Ltd., with a displacement of 12.9L and a turbocharger and intercooler.

1C 1342358 Chassis DYNAMO implements this test. The test for evaluating the effect of nitrogen oxides and difficult substance removal was carried out in accordance with the Japanese D_13 mode designed for heavy duty diesel engines. The diesel fuel used in this test was ultra low sulfur diesel with a sulfur content of 5 〇 Ppm. The results showed that the reduction ratio to carbon monoxide was 98%, the hydrocarbon-compound was 36%', the nitrogen oxide was 39%', and the particulate matter was 97〇/〇. Lu [Table 2] Japan HING company's automobile nitrogen oxide county and particulate matter removal test results i base g / KWh CO HC ΝΟχ PM 2.338 0.502 5.426 0.557 after installation of the device g / KWh 0.045 0.319 3.227 0.016 reduction ratio 98.1% 36.5% 39.6% 97.1% [Industrial Applicability] The exhaust gas purifying apparatus according to the present invention is an exhaust gas purifying apparatus in which 'the reduction performance of nitrogen oxides is excellent in a temperature range of 250 to 600 ° C of the true temperature of the exhaust gas, Moreover, the removal efficiency of the particulate matter is also excellent, and it is advantageous in that selective reduction of nitrogen oxides can be carried out by injection of diesel fuel, and the diesel particulate filter can be regenerated at the same time. Moreover, regardless of the operating state of the engine, the reduction performance is excellent, and the removal efficiency of CO, HC and helium is also excellent. 16 20 1342358 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an exhaust gas purifying apparatus of the present invention in the case where the DeNOx catalyst layer is one layer. Fig. 2 is a view showing an exhaust gas purifying apparatus of the present invention 5 in the case where the DeNOx catalyst layer is a plurality of layers. [Main component symbol description] 1 Nitrogen oxide reduction (DeNOx) catalyst unit | 2 Diesel particulate filter (DPF) unit 10 3 Diesel fuel injector

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Claims (1)

Amendment on September 1, 1999 丨 ΐ 91 Reprinted, (2) (Represented on September 1 of the Republic of China) (Submitted on September 1, 2010) 10 Patent application scope 1. 2. 3. 4. An exhaust gas purification device disposed in a diesel engine exhaust passage, including a majority of nitrogen oxide (DeNOx) reduction catalyst portion for reducing nitrogen oxides and diesel fuel for removing particulate matter The particulate filter (DPF) is provided successively from the upstream of the flow of the exhaust gas, wherein one of the diesel fuel injectors is installed in front of the nitrogen oxide reduction catalyst portion and the plurality of nitrogen oxide reduction catalyst portions are adjacently disposed. Within multiple layers. For example, the exhaust gas purifying device of the patent application scope item, wherein, the composition of the sea or the amount of r. :: Diesel granules are equipped with a pin family::##, wherein, α § § 青 青 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利The at least one of the group consisting of pt, P (1, Ir /, Rh). The exhaust gas purifying device of claim 4, wherein the diesel particulate filter has a platinum (Pt) component. 6. The exhaust gas purifying device of claim 3, wherein the diesel particulate filter has a supporting body made of heat-resistant ceramic or a genus material and coated with oxidized sulphur, sulphur dioxide, and titanium dioxide. a carrier of at least one of cerium oxide, oxidized salt or zeolite. 7. The exhaust gas purifying device according to claim 6, wherein the diesel = particulate filter carries 0.01 to 5 weight percent of platinum (pt) The component 'is used for the support body coated with the carrier. 8. The exhaust gas purifying device according to claim 7, wherein the firewood is 0: VPamela (PC) \96383-SK \96383 - 丨 .doc 18 20 9. The Qiuzuzu source is additionally provided with at least an oxidizing catalyst component selected from the group consisting of v, W, and M. In the case of the exhaust gas purifying device of the eighth aspect of the patent, in the case of i V oxygen: the support Ϊ L Π component applied to the carrier is _ to 2 weight percent, and in the case selected from the case, the support for the dragon service cloth The H-catalyst component is 〇.〇1 to 1 by weight. Milk 10. The exhaust gas purifying device according to item 3 of the patent application, :: reducing the catalyst portion with a component, copper one or;: 11 = Shen 1 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ The exhaust gas-purifying oxide reduction catalyst portion of the scope of the patent scope is additionally provided with 01 heavy-denier, (Ag) components for use in the carrier. The silver-purple 13H patent of the heavy-duty-knife ratio and the exhaust gas purification oxidation of the 12th item The material reduction catalyst unit additionally has a hard-to-touch component of 〇.〇〇重中百= for the carrier. .5重里百,比14. Ingredients, _ Yu Lai. 丨 1 heavy Dong percentage 15 · as in the scope of application of the scope of the exhaust gas purification device, The cockroach catalyst component is at least one selected from the group consisting of Pt, Pd, Ir, and Rh. 16. 5 If the catalyst component of the Group 15 is platinum (Pt). Where the platinum 20