Self-ignition resistant thermally-activated carbon

Patent metadata

Field	Value
Publication number	US-9358523-B2
Application number	US-201414515092-A
Country	US
Kind code	B2
Filing date	Oct 15, 2014
Priority date	Apr 1, 2009
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Thermally-activated cellulosic-based carbon is rendered more thermally stable by exposure to a halogen and/or a halogen-containing compound. Such treated cellulosic-based carbon is suitable for use in mitigating the content of hazardous substances in flue gases, especially flue gases having a temperature within the range of from about 100° C. to about 420° C.

First claim

That which is claimed is:

1. A thermally-activated cellulosic-based carbon that has been exposed to a halogen and/or a halogen-containing compound, has an ash content of 10 to 15 wt % and that has at least one of the following:
(i) a temperature of initial energy release that is greater than the temperature of initial energy release for the same thermally-activated cellulosic-based carbon without the halogen and/or halogen-containing compound exposure;
(ii) a self-sustaining ignition temperature greater than the self-sustaining ignition temperature for the same thermally-activated cellulosic-based carbon without the halogen and/or halogen-containing compound exposure; and
(iii) an early stage energy release value that is less than the early stage energy release value for the same thermally-activated cellulosic-based carbon without the halogen and/or halogen-containing compound exposure.

2. The thermally-activated cellulosic-based carbon of claim 1 wherein the halogen and/or halogen-containing compound comprises bromine, chlorine, fluorine, iodine, ammonium bromide, other nitrogen-containing halogen salts, or calcium bromide.

3. The thermally-activated cellulosic-based carbon of claim 1 wherein the thermally-activated cellulosic-based carbon that has been exposed to a halogen or halogen-containing compound contains from about 2 to about 20 wt % halogen, the wt % being based on the total weight of the thermally-activated cellulosic-based carbon that had been exposed to the halogen and/or the halogen-containing compound.

4. A process for enhancing the thermal stability of a thermally-activated cellulosic-based carbon, which process comprises exposing the thermally-activated cellulosic-based carbon to a halogen and/or a halogen-containing compound at a temperature and for a time sufficient so that thermally-activated cellulosic-based carbon that has been exposed to the halogen and/or the halogen-containing compound, has an ash content of 10 to 15 wt % and has at least one of the following:
(i) a temperature of initial energy release greater than the temperature of initial energy release for the same thermally-activated cellulosic-based carbon prior to the halogen and/or halogen-containing compound exposure;
(ii) a self-sustaining ignition temperature greater than the self-sustaining ignition temperature for the same thermally-activated cellulosic-based carbon prior to the halogen and/or halogen-containing compound exposure; and
(iii) an early stage energy release value that is less than the early stage energy release value for the same thermally-activated cellulosic-based carbon prior to the halogen and/or halogen-containing compound exposure.

5. The process of claim 4 wherein the halogen and/or halogen-containing compound comprises bromine, chlorine, fluorine, iodine, ammonium bromide, other nitrogen-containing halogen salts, or calcium bromide.

6. The process of claim 4 wherein the thermally-activated cellulosic-based carbon is exposed to the halogen and/or the halogen-containing compound at a temperature from 82 to 105° C. and for a period of time within the range of from 0.1 to 3 seconds.

7. A halogen and/or halogen-containing compound exposed, thermally-activated cellulosic based carbon that contains from about 2 to about 20 wt % halogen, has an ash content of 10 to 15 wt %, is prepared absent contact with acid, water or a combination thereof and has at least one of the following:
(i) a temperature of initial energy release that is greater than the temperature of initial energy release for the same thermally-activated cellulosic based carbon prior to the halogen and/or halogen-containing compound exposure,
(ii) a self-sustaining ignition temperature greater than the self-sustaining ignition temperature for the same thermally-activated cellulosic-based carbon prior to the halogen and/or halogen-containing compound exposure; and
(iii) an early stage energy release value that is less than the early stage energy release value for the same thermally-activated cellulosic-based carbon prior to the halogen and/or halogen-containing compound exposure.

8. The thermally-activated cellulosic-based carbon of claim 7 wherein the halogen and/or halogen-containing compound comprises bromine, chlorine, fluorine, iodine, ammonium bromide, other nitrogen-containing halogen salts, or calcium bromide.

Assignees

• Albemarle Corp

Inventors

• O'Dwyer Jonathan P
• Zhou Qunhui
• Lambeth Gregory H
• Zhang Yinzhi
• Nalepa Christopher J

Classifications

• B01D2253/102

  Carbon · CPC title

• B01D2257/302

  Sulfur oxides · CPC title

• B01J20/22

  comprising organic material · CPC title

• B01D53/02

  by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)} · CPC title

• Y02C20/10

  of nitrous oxide (N2O) · CPC title