A MODULARIZED CATALYTIC CONVERTER AND A METHOD OF ENHANCING THE EFFICIENCY OF A CATALYTIC CONVERTER

Abstract

A catalytic converter module assembly comprises a plurality of catalytic converter modules arranged in series such that gas may be fed through successive catalytic converter modules. Each catalytic converter module comprises a catalytic converter having one or more catalytic converter members arranged and configured for fluid contact with a gas, and a heat generator arranged close to and upstream of the catalytic converter. The heat generator and the catalytic converter are arranged in fluid communication and interconnected by connection means so as to form a unitary device. The invention allows for heating a gas flowing past the heat generator substantially immediately before the gas is exposed to the catalytic converter or catalytic converter member, whereby the efficiency of a catalytic converter is enhanced. The invention is particularly useful for cleaning non-combusted hydrocarbons, such as methane, carbon monoxide, or nitrogen oxides, in the exhaust gas.

Claims

1. A catalytic converter module assembly, comprising a plurality of catalytic converter modules arranged in series such that a gas may be fed through successive catalytic converter modules and treated in stages.

2. The catalytic converter module assembly of claim 1, wherein a catalytic converter module of the plurality of catalytic converter modules comprises: a catalytic converter having one or more catalytic converter members arranged for fluid contact with the gas to be treated by the catalytic converter, and an electrically powered heat generator arranged adjacent to and upstream of the catalytic converter; wherein the heat generator and the catalytic converter are arranged in fluid communication and interconnected by a connection means so as to form a unitary device.

3. The catalytic converter module assembly of claim 2, wherein the heat generator is arranged a distance upstream of the catalytic converter, and a gas reaction zone is defined between at least one heating member in the heat generator and the one or more catalytic converter members.

4. The catalytic converter module assembly of claim 2, wherein the heat generator and the catalytic converter comprise screen-type designs.

5. The catalytic converter module assembly of claim 1, wherein the catalytic converter module assembly is arranged inside a thermally insulated conduit.

6. The catalytic converter module assembly of claim 2, wherein the heat generator comprises one or more heating members.

7. The catalytic converter module assembly of claim 2, wherein the heat generator comprises one or more turbulators.

8. The catalytic converter module assembly of claim 1, wherein the catalytic converter modules (have different catalyst material.

9. A cleaning assembly for treating exhaust gases from a thermal engine, comprising: an exhaust gas turbine fluidly connected to an exhaust gas conduit of the thermal engine and arranged to receive exhaust gas; a catalytic converter assembly configured for receiving the exhaust gas and for heating and treating the exhaust gas.

10. The cleaning assembly of claim 9, further comprising an electric generator driven by the exhaust gas turbine.

11. The cleaning assembly of claim 9, wherein the catalytic converter assembly is arranged upstream of the exhaust gas turbine.

12. The cleaning assembly of claim 9, wherein the catalytic converter assembly is arranged downstream of the exhaust gas turbine.

13. The cleaning assembly of claim 9, wherein the thermal engine is an internal combustion engine.

14. A method of enhancing an efficiency of a catalytic converter, the method comprising: providing a localized heat generator a distance upstream of the catalytic converter or a catalytic converter member; energizing the heat generator to heat a gas flowing past the heat generator substantially immediately before the gas is exposed to the catalytic converter or the catalytic converter member, and optimizing a heat input and a catalytic contact area of the gas to be treated when flowing through the catalytic converter.

15. A method of treating a gas, comprising subjecting the gas to repeated heating and cleaning stages as it passes through successive catalytic converter modules.

16. The method of claim 15, wherein the heat is generated in such a way as to optimize a temperature profile permanently or temporarily depending on system operating conditions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] These and other characteristics of the invention will become clear from the following description of embodiments of the invention, given as a non-restrictive examples, with reference to the attached schematic drawings, wherein:

[0024] FIG. 1 is a schematic sectional drawing of an embodiment of the catalytic converter module according to the invention, illustrating a typical arrangement of a heat generator in combination with a catalytic converter unit;

[0025] FIG. 2 is a perspective drawing, schematically illustrating an array of catalytic converter modules according to the invention arranged one downstream of the other, as a unitary package;

[0026] FIG. 3 is a schematic sectional drawing corresponding to FIG. 1, but illustrates an embodiment having turbulence-inducing heat generators;

[0027] FIG. 4 is a perspective drawing, schematically illustrating an alternative embodiment of the invention in which the catalytic converter module comprises a unit in which the catalytic converter members and heating members are combined into one unit where the catalytic converter members and heating members form a common mesh structure; and

[0028] FIG. 5 is diagram illustrating a system incorporating the catalytic converter module according to the invention used in association with an internal combustion engine.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0029] The following description may use terms such as “horizontal”, “vertical”, “lateral”, “back and forth”, “up and down”, “upper”, “lower”, “inner”, “outer”, “forward”, “rear”, etc. These terms generally refer to the views and orientations as shown in the drawings and that are associated with a normal use of the invention. The terms are used for the reader's convenience only and shall not be limiting.

[0030] Referring initially to FIG. 1, the invented catalytic converter module 1 comprises in the illustrated embodiment a catalytic converter 2 and a heat generator 3 arranged upstream and a short distance from of the catalytic converter 2. The heat generator 3 is illustrated as an electrically powered heat generator, having one or more heating members 3a in the form of resistance wires and a power cable 8 connected to an electrical power source (not shown). The heating members 3a are arranged in an electrically insulated housing 4. It should be understood that the heating member 3a may be any type of electrical heating source (e.g. positive temperature coefficient (PTC) element or resistance wire).

[0031] The catalytic converter 2 comprises a plurality of catalytic converter members 2a, such members per se being known in the art. These catalytic converter members are arranged in a frame 5 and such that they are exposed to gases flowing through the catalytic converter. Reference letter A denotes the center-to-center distance between the catalytic converter member 2a and the heating member 3a and defines a gas reaction zone A within the catalytic converter module 1.

[0032] The heat generator 3 is arranged adjacent to, and a distance X upstream of, the catalytic converter 2, and is connected to the catalytic converter 2 by connection means 6, here in the form of a clamp assembly 6. Although not illustrated, it should be understood that the connection means 6 may comprise bolts, adhesives and/or any other bonding means, and not be limited to the illustrated clamp assembly. The heat generator 3 and the catalytic converter 2 may in a preferred embodiment both be of screen-type designs, but other designs are conceivable. The distance X may be dimensioned according to the application at hand, and may range from zero to several centimetres. The combined effect of the heat generator 3 and the catalytic converter 2 together produces the cleaning reaction depending on various parameters, of which the size of the reaction zone A is of importance. The distance X, which may be defined a spacer element, ensures that the heat generator and catalytic converter are maintained at the right distance, and by changing the distance X, the extension of the reaction zone A may be optimized.

[0033] The catalytic converter module 1 is arranged inside a conduit 7, which may be a thermally insulated duct. Although not illustrated, the conduit 7 and the catalytic converter module 1 may have a circular cross-section or a rectangular cross-section. The invention shall not be limited to cross-sectional shape. A plurality of catalytic converter modules 1.sub.1, 1.sub.2, . . . 1.sub.n may thus be arranged one downstream of the other, in an array (assembly) 30, as illustrated in FIG. 2, in order to enhance cleaning effect. One or more individual catalytic converter modules 1.sub.n may be removed for cleaning or inspection purposes, replacement, etc. Also, the array (assembly) 30 may comprise catalytic converter modules having different properties (e.g. catalyst material), depending on the application.

[0034] The “stacking” of catalytic converter modules 1 as shown in FIG. 2 may enable optimization of important reaction parameters such as temperature, residence time, flow conditions, catalyst material, etc. to the given exhaust treatment process(es). The exhaust gas is subjected to repeated heating and cleaning stages as it passes through successive catalytic converter modules 1.sub.1, 1.sub.2, . . . 1.sub.n.

[0035] In use, untreated exhaust gas E enters the heat generator 3 where it is exposed to high local temperatures in a zone of very limited axial distance before it immediately thereafter comes into contact with the catalytic converter members 2a in the catalytic converter 2. The arrow C in FIG. 1 denotes a treated gas.

[0036] The electric energy supplied to the heat generator 3 may be of a fixed amount or it may be actively controlled from a suitable unit (not shown). In the latter case, it is typically arranged as a closed-loop control system, where a feedback sensor(s) inside and/or downstream of the catalyst gives a signal back to the electric controller. The electric controller may further control the various electric heater members 3 individually and differently according to the system operation conditions. In this way, an active exhaust cleaning down to a pre-set emission value may be achieved, and the system may be safe-guarded.

[0037] The cleaning effect of a given catalytic converter module 1 is produced by the combined effect which the heat generator 3 and the catalytic converter 2 have on the exhaust stream E. In order to optimize this effect relative to the energy consumption, size etc., various ways of arranging the heat generator and catalytic converter within a module may be possible.

[0038] FIG. 3 illustrates another embodiment of the heat generator 3, in which one or more of the heating members 3b are shaped and arranged to function as turbulence generators. Although not illustrated, it should be understood that the heat generator may comprise heating members and turbulence generators also as separate members. The turbulence generators will influence the gas flowing though the reaction zone A, and thus contribute to improved cleaning efficiency for certain applications. The turbulence generators will also contribute to removing particles, oxides, etc., that may tend to accumulate in the catalytic converter with use.

[0039] FIG. 4 illustrates another embodiment of the catalytic converter module 1′, in which a plurality of catalytic converter members 2a and heating members 3b are shaped as elongated members and interconnected to form a common screen (mesh).

[0040] FIG. 5 illustrates an application of the invented catalytic converter assembly 30, arranged in a cleaning assembly 20 to treat exhaust gases from a thermal engine 10 (e.g. an internal combustion engine). The cleaning assembly 20 comprises an exhaust gas turbine 21, fluidly connected to the exhaust gas conduit (e.g. manifold) 11 of the thermal engine 10 and arranged to receive exhaust gas E. The exhaust gas turbine 21 is driving an electric generator 24 via a shaft 27, in a manner which per se is known in the art. The exhaust gas is fed into the catalytic converter assembly 30, which heats and treats (cleans) the gas as described above. Electrical power is supplied to the catalytic converter assembly 30 via power line 25. Reference number 26 denotes an external electrical power supply. Boxes drawn in dotted lines indicate alternative arrangements for the electric generator 24 and the catalytic converter assembly 30. The exhaust gas turbine 21 may also be driving an inlet compressor 22 which is fluidly connected to an inlet manifold 23.

[0041] The exhaust turbine 21 as well as the generator 24 may preferably be part of an exhaust turbocharger, and the turbocharger and catalytic converter assembly 30 may be arranged in a suitable way to make up a exhaust cleaning assembly 20.