Exhaust gas treatment device
View Patent ↗A mounting mat for an exhaust gas treatment device includes a blend of inorganic fibers and organic nanofibrillated fibers. An exhaust gas treatment device includes a housing and a fragile structure mounted within the housing by the mounting mat that is disposed in a gap between the housing and the fragile catalyst support structure. Additionally disclosed are methods of making a mounting mat for an exhaust gas treatment device and for making an exhaust gas treatment device incorporating the mounting mat.
1. An exhaust gas treatment device comprising:
a housing;
a fragile structure mounted within the housing; and
a mounting mat disposed in a gap between the housing and the fragile structure comprising inorganic fibers and organic nanofibrillated fibers.
2. The exhaust gas treatment device of claim 1 , wherein the inorganic fibers are selected from the group consisting of high alumina polycrystalline fibers, ceramic fibers, mullite fibers, glass fibers, biosoluble fibers, quartz fibers, silica fibers, and combinations thereof.
3. The exhaust gas treatment device of claim 2 , wherein the high alumina polycrystalline fibers comprise the fiberization product of about 72 to about 100 weight percent alumina and about 0 to about 28 weight percent silica.
4. The exhaust gas treatment device of claim 2 , wherein the ceramic fibers comprise alumino-silicate fibers comprising the fiberization product of about 45 to about 72 weight percent alumina and about 28 to about 55 weight percent silica.
5. The exhaust gas treatment device of claim 2 , wherein the biosoluble fibers comprise magnesia-silica fibers comprising the fiberization product of about 65 to about 86 weight percent silica, from about 14 to about 35 weight percent magnesia and about 5 weight percent of less impurities.
6. The exhaust gas treatment device of claim 2 , wherein the biosoluble fibers comprise calcia-magnesia-silica fibers comprising the fiberization product of about 45 to about 90 weight percent silica, greater than 0 to about 45 weight percent calcia, and greater than 0 to about 35 weight percent magnesia.
7. The exhaust gas treatment device of claim 1 , wherein the majority of the organic nanofibrillated fibers have a diameter of less than 1 μm.
8. The exhaust gas treatment device of claim 1 , wherein greater than 80% of the organic nanofibrillated fibers have diameter of less than 1 μm.
9. The exhaust gas treatment device of claim 1 , wherein substantially all of the organic nanofibrillated fibers have a diameter of less than 1 μm.
10. The exhaust gas treatment device of claim 1 , wherein the organic nanofibrillated fibers have an average diameter of from about 50 nm to about 500 nm.
11. The exhaust gas treatment device of claim 1 , wherein said organic nanofibrillated fibers comprise at least one of acrylic nanofibrillated fibers, natural cellulose nanofibrillated fibers, or regenerated cellulose nanofibrillated fibers.
12. The exhaust gas treatment device of claim 11 , wherein said mounting mat comprises greater than 0 to about 10 weight percent cellulose nanofibrillated fibers.
13. The exhaust gas treatment device of claim 1 , wherein said mounting mat comprises an intumescent material selected from the group consisting of unexpanded vermiculite, ion exchanged vermiculite, heat treated vermiculite, expandable graphite, hydrobiotite, water-swelling tetrasilicic flourine mica, alkaline metal silicates, or mixtures thereof.
14. The exhaust gas treatment device of claim 13 , wherein the intumescent material comprises unexpanded vermiculite.
15. The exhaust gas treatment device of claim 1 , wherein said mounting mat comprises a clay selected from the group consisting of attapulgite, ball clay, bentonite, hectorite, kyanite, kaolinite, montmorillonite, palygorskite, saponite, sepiolite, silimanite or combinations thereof.
16. The exhaust gas treatment device of claim 1 , comprising an organic binder different from the organic nanofibrillated fibers.
17. The exhaust gas treatment device of claim 16 , wherein said organic binder comprises an acrylic latex.
18. The exhaust gas treatment device of claim 1 , wherein the device is a catalytic converter or diesel particulate trap.
19. An exhaust gas treatment device comprising:
a housing;
a fragile structure located within the housing; and
a mounting mat disposed in a gap between said housing and said fragile structure;
a double walled end cone housing; and
an insulation mat or molded three dimensional insulation pre-form disposed between the walls of the end cone housing, said insulation mat or pre-form comprising a blend of inorganic fibers and organic nanofibrillated fibers.
20. The exhaust gas treatment device of claim 19 , wherein the insulation mat comprises a non-intumescent mat.
21. The exhaust gas treatment device of claim 19 , wherein the insulation mat comprises an intumescent mat.
22. The exhaust gas treatment device of claim 19 , wherein the inorganic fibers are selected from the group consisting of high alumina polycrystalline fibers, ceramic fibers, mullite fibers, glass fibers, biosoluble fibers, quartz fibers, silica fibers, and combinations thereof.
23. An end cone for an exhaust gas treatment device comprising:
an outer metallic cone;
an inner metallic cone; and
cone insulation disposed between said outer and inner metallic cones, said cone insulation comprising a layer comprising a blend of inorganic fibers, organic nanofibrillated fibers, and optionally intumescent material.
24. The end cone for an exhaust gas treatment device of claim 23 , wherein said organic nanofibrillated fibers comprise at least one of acrylic nanofibrillated fibers, natural cellulose nanofibrillated fibers, or regenerated cellulose nanofibrillated fibers.
25. The end cone for an exhaust gas treatment device of claim 23 , wherein said end cone for an exhaust gas treatment device comprises greater than 0 to about 10 weight percent cellulose nanofibrillated fibers.
26. An end cone for an exhaust gas treatment device comprising:
an outer metallic cone; and
self-supporting cone insulation comprising a blend of inorganic fibers, organic nanofibrillated fibers, and optionally intumescent material disposed adjacent to the inner surface of said outer metallic cone.
27. The end cone for an exhaust gas treatment device of claim 26 , wherein said organic nanofibrillated fibers comprise at least one of acrylic nanofibrillated fibers, natural cellulose nanofibrillated fibers, or regenerated cellulose nanofibrillated fibers.
28. The end cone for an exhaust gas treatment device of claim 26 , wherein said layer of said cone insulation comprises greater than 0 to about 10 weight percent cellulose nanofibrillated fibers.
29. A double-walled automotive exhaust gas pipe comprising:
an outer metallic pipe;
an inner metallic pipe; and
pipe insulation disposed between said outer and inner metallic pipes, said pipe insulation comprising inorganic fibers, organic nanofibrillated fibers, and optionally intumescent material.
30. The double-walled automotive exhaust gas pipe of claim 29 , wherein said organic nanofibrillated fibers comprise at least one of acrylic nanofibrillated fibers, natural cellulose nanofibrillated fibers, or regenerated cellulose nanofibrillated fibers.
31. The double-walled automotive exhaust gas pipe of claim 29 , wherein said pipe insulation comprises greater than 0 to about 10 weight percent cellulose nanofibrillated fibers.