US4762537A — Adsorbent for HCl comprising alumina and acid-tre…

Claim 1

Independent Claim 109 words

A method for removing HCl from a gas containing less than about 100 ppm HCl, comprising removing said HCl by contacting said gas with a solid composite adsorbent having surface area greater than about 200 m 2 /g and comprising about 50-95 wt % alumina and about 5-50 wt % Y zeolite, said adsorbent being produced by treating Y zeolite particles with an aqueous acid solution to reduce their sodium silicate content, admixing the acid-treated Y zeolite particles with alumina particles, agglomerating the Y zeolite and alumina particles into a composite agglomerate, aging said agglomerate in the presence of water and activating the composite agglomerate at an elevated temperature.

Claim 2

Independent Claim 109 words

A method for removing HCl from a gas containing less than about 100 ppm HCl, comprising removing said HCl by contacting said gas with a solid composite adsorbent having surface area greater than about 200 m 2 /g and comprising about 50-95 wt % alumina and about 5-50 wt % Y zeolite, said adsorbent being produced by treating Y zeolite particles with an aqueous acid solution to reduce their sodium silicate content, admixing the acid-treated Y zeolite particles with alumina particles, agglomerating the Y zeolite and alumina particles into a composite agglomerate, aging said agglomerate in the presence of water and activating the composite agglomerate at an elevated temperature.

Claim 3

Dependent Claim 32 words

The method according to claim 1 wherein the Y zeolite particles have sufficiently low sodium silicate content that a 20 wt % aqueous slurry has a pH of less than about 10.42.

Claim 4

Dependent Claim 121 words

A composite adsorbent useful for adsorbing gaseous HCl, said adsorbent having surface area greater than about 200 m 2 /g and comprising (a) about 50-95 wt % alumina, and (b) about 5-50 wt % Y zeolite wherein the molar ratio of SiO 2 to Al 2 O 3 is about 4.5-6.0, said adsorbent being produced by admixing particles of alumina with particles of Y zeolite treated with an acid solution so that their sodium silicate content is sufficiently low that a 20 wt % aqueous slurry has a pH of less than about 10.42, agglomerating the alumina and Y zeolite particles into a composite agglomerate, aging said agglomerate in the presence of water and activating said agglomerate at an elevated temperature.

Claim 5

Dependent Claim 121 words

A composite adsorbent useful for adsorbing gaseous HCl, said adsorbent having surface area greater than about 200 m 2 /g and comprising (a) about 50-95 wt % alumina, and (b) about 5-50 wt % Y zeolite wherein the molar ratio of SiO 2 to Al 2 O 3 is about 4.5-6.0, said adsorbent being produced by admixing particles of alumina with particles of Y zeolite treated with an acid solution so that their sodium silicate content is sufficiently low that a 20 wt % aqueous slurry has a pH of less than about 10.42, agglomerating the alumina and Y zeolite particles into a composite agglomerate, aging said agglomerate in the presence of water and activating said agglomerate at an elevated temperature.

Claim 6

Dependent Claim 23 words

The adsorbent of claim 3 wherein the alumina particles include activated alumina having an average particle size of about 10 microns or less.

Claim 7

Dependent Claim 24 words

The adsorbent of claim 4 wherein the molar ratio of SiO 2 to A 2 O 3 in the Y zeolite is about 4.8-6.0.

Claim 8

Dependent Claim 18 words

The adsorbent of claim 4 comprising about 70-80 wt % alumina and about 20-30 wt % Y zeolite.

Claim 9

Dependent Claim 13 words

The adsorbent of claim 4 wherein said Y zeolite comprises sodium Y zeolite.

Claim 10

Dependent Claim 27 words

The adsorbent of claim 4 having a surface area of greater than about 300 m 2 /g and an LOI of less than about 6.0 wt %.

Claim 11

Dependent Claim 22 words

The adsorbent of claim 3 wherein said acid solution is an aqueous solution of an acid having a pK of about 4-7.

Claim 12

Dependent Claim 11 words

The adsorbent of claim 9 wherein said acid is acetic acid.

Claim 13

Dependent Claim 25 words

The adsorbent of claim 3 wherein said composite agglomerate is aged at a pH greater than 7 and at a temperature of about 0°-60 C.

Claim 14

Independent Claim 117 words

A method for producing a composite adsorbent useful for adsorbing gaseous HCl, said method comprising (a) treating particles of Y zeolite with an aqueous acid solution to reduce the sodium silicate content, said Y zeolite particles having an average particle size of less than about 10 microns, (b) sizing alumina to an average particle size of about 10 microns or less, (c) agglomerating the alumina particles in the presence of water with the Y zeolite particles, thereby to form a composite agglomerate, (d) aging the composite agglomerate in the presence of water at pH greater than 7 to strengthen the agglomerate, and (e) activating the composite agglomerate by exposure to an elevated temperature of about 420°-550° C.

Claim 15

Independent Claim 117 words

A method for producing a composite adsorbent useful for adsorbing gaseous HCl, said method comprising (a) treating particles of Y zeolite with an aqueous acid solution to reduce the sodium silicate content, said Y zeolite particles having an average particle size of less than about 10 microns, (b) sizing alumina to an average particle size of about 10 microns or less, (c) agglomerating the alumina particles in the presence of water with the Y zeolite particles, thereby to form a composite agglomerate, (d) aging the composite agglomerate in the presence of water at pH greater than 7 to strengthen the agglomerate, and (e) activating the composite agglomerate by exposure to an elevated temperature of about 420°-550° C.

Claim 16

Dependent Claim 48 words

The method according to claim 12 further comprising, prior to step (c) (f) rapidly activating the sized alumina particles by exposure to an elevated temperature of about 300°-1000° C. for less than one minute, thereby to form activated alumina particles having an LOI of about 6-10 wt %.

Claim 17

Dependent Claim 28 words

The method according to claim 13 wherein step (a) comprises treating said Y zeolite particles with an aqueous solution of an acid having a pK of about 4-7.

Claim 18

Dependent Claim 12 words

The method according to claim 14 wherein said acid is acetic acid.

Claim 19

Dependent Claim 20 words

The method according to claim 14 wherein the Y zeolite particles have an average particle size of about 3-5 microns.

Claim 20

Dependent Claim 25 words

The method according to claim 14 wherein the molar ratio of SiO 2 to Al 2 O 3 in the Y zeolite is about 4.5-6.0.

Claim 21

Dependent Claim 25 words

The method according to claim 14 wherein step (c) comprises combining about 50-95 wt % activated alumina with about 5-50 wt % sodium Y zeolite.

Claim 22

Dependent Claim 18 words

The method according to claim 14 wherein step (d) is performed at a temperature of about 0°-60° C.

Claim 23

Dependent Claim 18 words

The method according to claim 14 wherein step (e) is performed at a temperature of about 420°-475° C.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-08-09	1992-02-08	1992-08-09	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-08-09	1996-02-08	1996-08-09	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-08-09	2000-02-08	2000-08-09	$7700.00	Window Closed / Lapsed

Adsorbent for HCl comprising alumina and acid-treated Y zeolite

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