US 12,357,981 B2
Particulate filters
Sabina Burmester, Royston (GB); Thomas Hotchkiss, Royston (GB); David Marvell, Royston (GB); and Jonathon Paul Sapsford, Royston (GB)
Assigned to Johnson Matthey Public Limited Company, London (GB)
Filed by JOHNSON MATTHEY PUBLIC LIMITED COMPANY, London (GB)
Filed on Feb. 2, 2022, as Appl. No. 17/649,730.
Claims priority of provisional application 63/200,075, filed on Feb. 12, 2021.
Prior Publication US 2022/0258150 A1, Aug. 18, 2022
Int. Cl. B01J 37/02 (2006.01); B01D 46/00 (2022.01); B01D 46/24 (2006.01); B01J 35/31 (2024.01); B01J 35/40 (2024.01); B01J 35/56 (2024.01); B01J 37/03 (2006.01); B01J 37/08 (2006.01); F01N 3/035 (2006.01)
CPC B01J 37/0217 (2013.01) [B01D 46/0001 (2013.01); B01D 46/0027 (2013.01); B01D 46/24 (2013.01); B01J 35/31 (2024.01); B01J 35/40 (2024.01); B01J 35/56 (2024.01); B01J 37/038 (2013.01); B01J 37/082 (2013.01); F01N 3/035 (2013.01); B01D 2279/30 (2013.01); F01N 2510/06 (2013.01)] 17 Claims
 
1. A method for treating a filter for filtering particulate matter from exhaust gas, the method comprising the steps of:
a) containing a dry powder in a reservoir;
b) locating a filter in a filter holder, the filter comprising a porous substrate having an inlet face and an outlet face, the inlet face and the outlet face being separated by a porous structure;
c) establishing a primary gas flow through the porous structure of the filter by applying a pressure reduction to the outlet face of the filter;
d) transferring the dry powder from the reservoir to a spray device located upstream of the inlet face of the filter;
e) spraying the dry powder, by use of the spray device, towards the inlet face of the filter such that the dry powder is entrained in the primary gas flow and passes through the inlet face of the filter to contact the porous structure; and
f) monitoring a back pressure of the filter during at least step e) and stopping the spraying of the dry powder towards the inlet face of the filter when:
pBP≥ptarget−poffset
where,
pBP is the back pressure of the filter;
ptarget is a pre-determined target back pressure for the filter; and
poffset is a pre-chosen offset pressure.