VOC mitigation in cured in place pipe installation
A method for removing VOCs from exhaust gases of a CIPP curing process, the method including the steps of: (a) positioning an exhaust conduit to capture the exhaust gases; (b) elevating the temperature of at least a portion of the exhaust gases and passing the exhaust gases over a catalyst containing substrate to form a devolitized gas stream; and (c) directing the devolitized gas stream to an exhaust stack.
1. An apparatus for removing VOCs from exhaust gases of a CIPP curing process, the apparatus including a housing which comprises:
(a) a primary exhaust stream conduit from a CIPP liner;
(b) a fan configured to collect fugitive exhaust and directed it into a fugitive exhaust stream;
(c) a mixing chamber combining the heated fugitive exhaust stream and the primary exhaust stream to form a combined exhaust stream;
(d) a heated, hydrophobic catalyst structure receiving the combined exhaust stream;
(e) an exhaust stack receiving the combined exhaust stream from the preheater and reducing the combined exhaust stream to under 105° C.
2. The apparatus of claim 1 , further comprising a preheater receiving the fugitive exhaust stream and configured to raise the fugitive exhaust stream to at least 90° C., while the primary exhaust stream bypasses the preheater.
3. The apparatus of claim 2 , further comprising a return line directing the combined exhaust stream from the catalyst structure to a heating fluid inlet of the preheater.
4. An apparatus for removing VOCs from exhaust gases of a CIPP curing process, the apparatus comprising:
(a) an entry exhaust stream conduit configured to receive exhaust curing steam from a pipe lined with a CIPP liner used to cure the CIPP liner;
(b) a VOC filter comprising a container in fluid communication with the entry exhaust stream conduit for receiving the exhaust curing steam from the entry exhaust stream conduit, and a hydrophobic active catalyst structure formed for receiving the exhaust curing steam through the catalyst structure, the catalyst structure being heatable to a temperature above ambient selected to promote removal of styrene from the exhaust curing steam; and
(c) an exit exhaust stream conduit in fluid communication with the VOC filter to receive filtered exhaust curing steam from the VOC filter and exhaust the exhaust curing steam.
5. The apparatus of claim 4 wherein the catalyst structure is configured to be electrically heated.
6. The apparatus of claim 4 wherein the catalyst structure comprises a catalyst washcoat on a metallic foil substrate.
7. The apparatus of claim 6 wherein the catalyst structure further comprises an active catalyst carried by the catalyst washcoat.
8. The apparatus of claim 7 wherein the active catalyst is one of platinum, palladium, or rhodium.
9. The apparatus of claim 7 wherein the catalyst washcoat comprises a porous catalyst carrier material on which the active catalyst is dispersed.
10. The apparatus of claim 9 wherein the carrier material comprises alumina (Al 2 O 3 ).
11. A method of treating exhaust steam containing VOCs from a curing process for CIPP liner, the method comprising:
attaching an entry exhaust stream conduit to the CIPP liner so that exhaust curing steam from the CIPP liner passes into the conduit;
passing exhaust curing steam from the CIPP liner into the entry exhaust stream conduit through a heated catalyst structure configured to reduce an oxidization temperature of styrene in the exhaust steam thereby to remove styrene from the exhaust steam; and
discharge exhaust curing steam to the environment after passing through the heated catalyst structure.
12. The method of claim 11 further including heating the catalyst structure with an electrical heating system.