JP2013510990A - Use of powder coated nickel foam as a resistor to increase the temperature of a catalytic converter device by using electricity - Google Patents

Abstract

The disclosed invention relates to optimizing the catalytic reaction of a diesel engine. Powder coated nickel or other metal foam is used as a substrate and resistor for catalytic converters. The disclosed method uses a closed loop system that uses a current to heat the metallic foam to raise the temperature of the diesel exhaust, thereby optimizing the temperature at which the catalytic reaction occurs. The disclosed equipment comprises a metal foam substrate with a catalyst coating. The substrate is heated using an electric current to optimize the catalytic reaction. Various washcoats and / or catalysts can be used to coat the metal foam substrate, and the optimum temperature depends on the catalyst used.
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Description

  The present disclosure relates to optimization of catalytic converter reactions. More precisely, the present disclosure relates to the use of powder coated nickel foam as a resistor to increase the temperature of the catalytic converter device and thereby increase the efficiency of the device.

  The temperature of the catalytic converter is one of the most important factors affecting the efficiency of the catalytic converter. The efficiency drops rapidly at both high and low temperatures, and the operating temperature band where the efficiency is maximum is limited to a relatively narrow band. Most importantly, when an automobile or truck engine begins to operate, the catalytic converter is at a temperature that is too low to produce the reaction necessary to reduce pollutants in the exhaust. When the engine starts, the catalytic converter does nothing at all to reduce pollutants in the exhaust.

To date, many catalytic converters have catalyzed a harmful exhaust gas, mainly carbon monoxide (CO) and nitrogen oxide (NO), which are less harmful gases, mainly carbon dioxide and nitrogen ( The heat present in the exhaust stream of a vehicle has been used to generate the temperature necessary to convert it into N ₂ ) and oxygen (O ₂ ) and exhale it into the atmosphere. One solution that has been used to heat the catalytic converter is to move the catalytic converter closer to the engine so that hotter exhaust gases can reach the converter. This arrangement allows the catalytic converter to warm up more quickly, but exposing the converter to very high temperatures can shorten the life of the converter.

  Preheating the catalytic converter is another way to increase efficiency and reduce emissions. One of the most popular ways to preheat the transducer is to use an electrical resistance heater. In the 12-volt electrical system on most passenger cars and trucks, it is impossible to provide enough energy or power to heat the catalytic converter quickly enough. A hybrid vehicle with a high voltage battery pack may be able to provide enough power to raise the temperature of the catalytic converter very quickly.

Compared to standard engines, diesel engine catalytic converters are even less efficient because they operate at lower temperatures. One solution to this problem is a system that injects a urea solution (an organic compound made of carbon, nitrogen, oxygen, and hydrogen) into the exhaust pipe before it reaches the converter. Urea was evaporated and mixed with the exhaust, causing a chemical reaction to reduce nitrogen oxides (NO _X). Urea reacts with NO _X to generate nitrogen and water vapor, so that nitrogen oxides in the exhaust gas are reduced. Another method is to heat the diesel particulate trap to such an extent that the soot formed in the trap as a result of the condensation of soluble organics in the exhaust stream can be incinerated. This heating is achieved thermally using exhaust gas.

  The present invention uses the metal foam as a support for the catalyst (s) and is also attached to the closed loop thermostat adjustable control device and used as the resistor itself. The present invention uses the residual electrical energy produced by the engine in the same manner as other electronic devices such as vehicle radios, allowing the catalytic converter to perform a more efficient temperature directly to carry out the catalytic reaction. To heat. The disclosed invention provides a method for optimizing diesel engine exhaust temperature by providing a substrate comprising a metal foam, coating the substrate with a catalytic material, and using an electric current to catalyze the substrate. Heating to a temperature range designed to optimize the reaction and flowing a diesel engine exhaust over the substrate to cause the catalytic material to interact with the exhaust. In all embodiments of the invention, the substrate is assumed to be in the form of a nickel foam or a metal foam. The catalyst material may further comprise a washcoat. The catalyst material could be composed of various catalysts, including iron manganese catalysts, titanium dioxide catalysts, selective catalytic reduction (“SCR”) catalysts, or platinum catalysts.

  The disclosed invention further includes, in a diesel engine exhaust system, a housing having an inlet for receiving diesel exhaust, a metallic foam substrate having a catalyst coating in the housing, and the substrate. It comprises a diesel engine exhaust system comprising an electrical system for heating and an outlet for exhausting diesel engine exhaust. In all embodiments of the system, the substrate is assumed to be in the form of a nickel foam or other metal foam. The catalyst coating may further comprise a washcoat. The catalyst coating could be composed of various catalysts including iron manganese catalyst, titanium dioxide catalyst, SCR catalyst, or platinum catalyst.

1 is a schematic diagram of a metal foam substrate / resistor that is the subject of a claim, showing a current source 1, a DC control device 2, a metal foam sheet 3, a bus bar 4, a thermocouple or other high temperature measuring device 5. . 1 is a schematic diagram of a catalytic converter device, showing the flow of exhaust 1, a catalyst 2 to be energized, and a foam substrate 3 included, a control unit 4, a diesel particulate filter 5, a second catalyst 6 and a housing 7. Yes.

  The disclosed invention describes the use of powder coated nickel foam as a resistor to increase the temperature of the catalytic converter device and thereby increase the efficiency of the device. Traditionally, catalytic converters have several components: (1) substrates, most often ceramic honeycombs or stainless steel foil honeycombs, (2) washcoats, often Is a mixture of silicon, aluminum, and other elements, a washcoat that forms a rough, uneven surface having a surface area much larger than the substrate surface, and (3) the catalyst itself, often in the form of platinum or palladium. It consists of a catalyst that is a noble metal. The catalyst is added to the washcoat (suspension) before being applied to the substrate.

  In the disclosed method and equipment, the base is a powder-coated nickel foam, which is held by Inco Limited, “open pore metal foam, dated 20 February 2006. It is manufactured according to the process disclosed in German Patent DE 1025000060091A1 entitled "Diesel particulate filter with". Thanks to the excellent ductility and high flexibility of the 100% open pore material, the substrate design can be freely determined. Different porosity makes it possible to define the level of depth filtration of the system. The foam, combined with its high temperature and corrosion resistance and very good soot storage capacity, serves as an effective substrate. During the manufacturing process, the nickel metal foam is coated with a high alloy powder tailored to a specific application and design and subjected to a heat treatment. Melting occurs and enlarges the specific surface area of the light metal foam. At the same time, the temperature resistance of the thermally conductive alloy foam increases to 1000 ° C., and the peak reaches 1200 ° C. The foam is flexible and ductile and can be cut at any length. The material can also be sintered and manufactured as a sheet. Other types of metal resistance products are also known in the art and could be used with the disclosed methods and equipment.

Many different washcoats and / or catalysts can be applied to the foam to make it usable as a catalytic converter. The catalyst being applied increases the amount of nitrogen dioxide (NO ₂ ), decreases the amount of nitrogen oxides (NO _x ), decreases the content of carbon monoxide (CO), and the content of hydrocarbons Reduce. Further, the foam can function as a passively regenerating DPF. As disclosed in German Patent DE 102006009164A1, the powder coating applied to the nickel foam is a combination of iron and chromium. After the powder is applied, the material is sintered into a material with a larger surface area.

Powder coated nickel foam is not a catalyst itself, but is a good support for a catalyst material containing a suitable washcoat and / or catalyst. The foam has at least four different catalyst coatings: (1) an iron-manganese catalyst that converts CO to carbon dioxide (CO ₂ ), (2) converts CO to CO _2, and converts hydrocarbons to CO ₂ and water vapor A catalyst washcoat and platinum catalyst that converts to (3) a catalyst made from titanium dioxide (TO ₂ ) that converts NO ₂ to nitric oxide (NO), and (4) NO _X to nitrogen gas ( N ₂ ) and a catalyst that converts to water are applied. The catalyst for converting NO _X into nitrogen gas (N ₂ ) and water may be any type of SCR catalyst, including base metal (such as vanadium and tungsten) oxides and zeolite. Other catalyst coatings exist commercially or in current technology, and they can also be applied to nickel foam.

  It is well known that for each catalyst material there is a temperature at which the catalyst is most effective. In many diesel systems, exhaust emissions never reach the temperature at which the catalyst is most effective or only slowly. In the disclosed embodiment, the metal foam being used as the catalyst support is fed with current to control the catalyst to the most efficient temperature using a small amount of current. Current is generated as a by-product of engine activity, so it is not necessary to introduce additional energy into the engine system. The system is a closed loop system using a thermocouple that measures the temperature of the exhaust stream and then adjusts the amount of current to maintain a preselected temperature. The circuit configuration for the system could be designed without undue experimentation by those skilled in the electronic arts.

  The disclosed equipment consists of an adjustable DC electrical source with a circuit attached to either a battery or a power source that can supply a moderate current to increase the temperature of the metal foam. The current source is a proportional control that receives temperature input from a thermocouple or from other types of temperature sensors including, but not limited to, resistance thermometers, filled thermometers, bimetal thermometers, or radiation pyrometers. It is controlled in a thermostatic manner by the device. The system further includes a controller that can be constructed in accordance with the apparatus described in Chapter 22 of the Chemical Engineer's Handbook. The current is carried by wiring connected to buses connected to opposite sides of the sheet or other form of metal foam. The foam is a container that receives the exhaust from the engine and is mounted in a container such as is typically used to contain the catalytic converter support. However, in the disclosed invention, the catalyst support also serves as a heater that heats the catalyst and surrounding exhaust to an optimum temperature.

(Figure 1)
1 Metal foam substrate / resistor current source 2 Metal foam substrate / resistor DC control device 3 Metal foam substrate / resistor metal foam sheet 4 Metal foam substrate / resistor bus 5 Thermocouple or other high-temperature measuring device for metal foam substrate and resistor (Figure 2)
DESCRIPTION OF SYMBOLS 1 Exhaust of catalyst converter device 2 Catalyst of catalyst converter device 3 Foam substrate of catalyst converter device 4 Control unit of catalyst converter device 5 Diesel particulate filter of catalyst converter device 6 Second catalyst of catalyst converter device 7 Housing for catalyst converter

Claims (36)

In a method of optimizing the temperature of diesel engine exhaust,
Providing a substrate comprising a metal foam coated with a catalytic material;
Heating the substrate to a temperature range designed to optimize the catalytic reaction by passing a current through the substrate;
Flowing the diesel engine exhaust above the substrate to cause the catalyst material to interact with the exhaust.   The method of claim 1, wherein the substrate is in the form of a nickel foam.   The method of claim 1, wherein a washcoat is combined with a catalyst to form the catalyst material.   The method of claim 1, wherein the catalyst material comprises an iron manganese catalyst.   The method of claim 1, wherein the catalyst material comprises a catalyst comprising titanium dioxide.   The method of claim 1, wherein the catalyst material comprises an SCR catalyst.   The method of claim 2, wherein a washcoat is combined with a catalyst to form the catalyst material.   The method of claim 2, wherein the catalyst material comprises an iron manganese catalyst.   The method of claim 2, wherein the catalyst material comprises a catalyst comprising titanium dioxide.   The method of claim 2, wherein the catalyst material comprises a catalyst comprising an SCR catalyst.   The method of claim 3, wherein the catalyst material comprises an iron manganese catalyst.   The method of claim 3, wherein the catalyst material comprises a catalyst comprising titanium dioxide.   4. The method of claim 3, wherein the catalyst material comprises a catalyst comprising an SCR catalyst.   The method of claim 3, wherein the catalyst material comprises a catalyst comprising platinum.   The method of claim 7, wherein the catalyst material comprises an iron manganese catalyst.   The method of claim 7, wherein the catalyst material comprises a catalyst comprising titanium dioxide.   The method of claim 7, wherein the catalyst material comprises a catalyst comprising an SCR catalyst.   The method of claim 7, wherein the catalyst material comprises a catalyst comprising platinum.   In a diesel engine exhaust system, a housing having an inlet for receiving diesel exhaust, a metal foam substrate within the housing having a catalyst coating, and an electrical system for heating the substrate; A diesel engine exhaust system comprising: an outlet for exhausting diesel engine exhaust;   The system of claim 19, wherein the substrate is in the form of a nickel foam.   The system of claim 19, wherein the catalyst coating further comprises a washcoat.   The system of claim 19, wherein the catalyst coating comprises an iron manganese catalyst.   The system of claim 19, wherein the catalyst coating comprises a catalyst comprising titanium dioxide.   The system of claim 19, wherein the catalyst coating comprises a catalyst comprising an SCR catalyst.   21. The system of claim 20, wherein the catalyst coating further comprises a washcoat.   21. The system of claim 20, wherein the catalyst coating comprises an iron manganese catalyst.   21. The system of claim 20, wherein the catalyst coating comprises a catalyst comprising titanium dioxide.   21. The system of claim 20, wherein the catalyst coating comprises a catalyst comprising an SCR catalyst.   The system of claim 21, wherein the catalyst coating comprises an iron manganese catalyst.   The method of claim 21, wherein the catalyst coating comprises a catalyst comprising titanium dioxide.   The system of claim 21, wherein the catalyst coating comprises a catalyst comprising an SCR catalyst.   The system of claim 21, wherein the catalyst material comprises a catalyst comprising platinum.   26. The system of claim 25, wherein the catalyst material comprises an iron manganese catalyst.   26. The system of claim 25, wherein the catalyst material comprises a catalyst comprising titanium dioxide.   26. The system of claim 25, wherein the catalyst material comprises a catalyst comprising an SCR catalyst.   26. The system of claim 25, wherein the catalyst material comprises a catalyst comprising platinum.

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