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INVENTION
Patent of the Russian Federation RU2082691
MINERAL ADHESIVE
Applicant Name: GKBoreskov Institute of Catalysis, SB RAS
The name of the inventor: Korotkikh OV; Barannik G.B.
The name of the patent holder: GKBoreskov Institute of Catalysis SB RAS
Address for correspondence:
Date of commencement of the patent: 1994.03.01
The invention relates to chemistry, in particular to a composition of an adhesive intended for gluing cassettes of different diameters from individual block catalysts of honeycomb structure to ceramic carriers. The problem solved by the invention is the development of a glue composition that has high thermal stability and resistance to the effects of aggressive media, water vapor and high pressure. This is achieved by the fact that the mineral glue contains ground silica fiber 15-35%, the product of thermal decomposition of gibbsite, or aluminum oxide, or aluminum hydroxide 15-35%, and the alumochromophosphate binder is the remainder.
DESCRIPTION OF THE INVENTION
The invention relates to a composition of a glue resistant to high temperature, aggressive media, high water vapor pressure and for the purpose of gluing different diameter cassettes from individual block catalysts on ceramic honeycomb carriers.
Known is a mineral glue containing an alumochromophosphate binder and a refractory filler as a synthetic cordierite chamotte and titanium dioxide in the following ratio, wt. [1]
Synthetic cordierite chamotte 45-48
Titanium Dioxide 10-12
Alumochromophosphate binder Other
The closest to the invention is a mineral glue containing an aluminochromophosphate binder derived from orthophosphoric acid, alumina hydrate, chromic anhydride, sodium sulfate and formalin, and silica, alumina and aluminum hydroxide [2]
The disadvantage of these adhesives is low resistance to thermal shock loads.
The object of the invention is to develop a glue composition for block catalysts on ceramic carriers of a honeycomb structure having, in addition to high thermal stability, resistance to the effects of corrosive media, water vapor and high pressure.
This is achieved by the fact that a mineral glue comprising silica, an oxygen-containing aluminum compound and an aluminochromophosphate binder, contains silica as a ground silica fiber, and as an oxygen-containing aluminum compound, the thermal decomposition product of gibbsite or aluminum oxide or aluminum hydroxide, in the following ratio, .
Ground silica fiber 15-35
Said oxygen-containing aluminum compound 35-15
Alumochromophosphate binder Other
Powdered silica is obtained by grinding silica fibers or a slab in a ball mill with lining and porcelain balls for 4 hours to a particle size of not more than 50 μm.
Knitting properties of the adhesive are formed due to the chemical interaction of the components of AChF (H 2 CrO 4 and H 3 PO 4 ) with the surface of mineral filler particles, resulting in the formation of aluminophosphates and silicophosphates.
The high thermal stability of the adhesive (up to 1200 o C) is explained by the amorphous, gel-like state of these compounds, which upon heating gradually harden, and their thermoplasticity due to the formation of eutectic mixtures with a low melting point in the systems: Al 2 O 3 -P 2 O 5 and SiO 2 -P 2 O 5 .
Example 1
35% of the ground silica fibers and 13% of the pulverized heat-dissolving product of gibbsite (PT) are mixed in a dry state. 52% of the alumochromophosphate binder with a concentration of at least 50% is introduced into the mixture of dry components. The mass is mixed until uniform and the spatula is applied to the adhesive surfaces of the block catalysts. The prepared catalyst cassette of the required size is calcined at 300 ° C for 1 hour in a muffle furnace.
Example 2
25% of the ground silica fibers and 25% of the powdery PT are mixed in a dry state. 50% of AChF with a concentration of at least 50% is introduced into the mixture of dry components. The mass is mixed until uniform, and the spatula is applied to the adherent surfaces of the block catalysts. The catalyst cassette prepared in the required size is calcined in a muffle furnace at 300 ° C for 1 hour.
Example 3
15% of the ground silica fibers and 35% of the powdery PT are mixed in a dry state. 50% of AChF with a concentration of at least 50% is introduced into the mixture of dry components. The mass is mixed until uniform, and the spatula is applied to the adherent surfaces of the block catalysts. The prepared catalytic cassette was calcined in a muffle furnace at 300 ° C. for 1 hour.
Example 4
23% of the ground silica fibers and 27% of the powdered alumina are mixed in a dry state. 50% of AChF with a concentration of at least 50% is introduced into the mixture of dry components. The mass is mixed until uniform, and the spatula is applied to the adherent surfaces of the block catalysts. The prepared catalyst cassette of the required size is calcined in a muffle furnace at 300 ° C for 1 hour.
The bond strength of the catalyst cassette was determined in several ways.
1. The glued samples were treated with saturated steam in an autoclave at P = 6 atm and T = 250 ° C for 3 hours.
2. Catalytic cassettes were tested in air-heating plants for two-stage combustion of natural gas at 400-900 ° C and a natural gas load of 40 to 80 m 3 / h, a test duration of 2,570 h.
3. Catalytic cassettes were tested in experimental installations for purification of geothermal steam from H 2 S (temperature up to 164 o C, pressure up to 6.9 atm, upper limit of hydrogen sulphide concentration was up to 18%, total test duration up to 65 h).
The tests carried out showed a high degree of strength of the proposed glue.
CLAIM
A mineral glue comprising silica, an oxygen-containing aluminum compound, and an aluminochromophosphate binder, characterized in that it contains a ground silica fiber as a silica, and as an oxygen-containing aluminum compound, the gibbsite thermal decomposition product or aluminum oxide or hydroxide aluminum at the following component ratio,
Ground silica fiber 15 35
Said oxygen-containing aluminum compound 15 35
Alumochromosphate binder rest
print version
Date of publication 18.12.2006гг
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