Evaporative emission control articles including activated carbon
The present disclosure relates to hydrocarbon emission control systems. More specifically, the present disclosure relates to substrates coated with hydrocarbon adsorptive coating compositions and evaporative emission control systems for controlling evaporative emissions of hydrocarbons from motor vehicle engines and fuel systems. The hydrocarbon adsorptive coating compositions include particulate carbon having a BET surface area of at least about 1300 m 2 /g, and at least one of (i) a butane affinity of greater than 60% at 5% butane; (ii) a butane affinity of greater than 35% at 0.5% butane; (iii) a micropore volume greater than about 0.2 mug and a mesopore volume greater than about 0.5 ml/g.
1. An evaporative emission control canister system comprising:
an evaporative emission control canister comprising no more than one canister adsorbent volume comprising a canister adsorbent material having a total canister adsorbent material volume, and
no more than one bleed emission scrubber;
wherein the bleed emission scrubber comprises no more than one scrubber adsorbent volume,
wherein the scrubber adsorbent volume comprises a scrubber adsorbent material and has a g-total butane working capacity (BWC) of 0.1 grams to less than 2 grams, wherein the g-total BWC is computed based on the total scrubber adsorbent volume and ASTM D5228 as of Jul. 16, 2018;
wherein the bleed emission scrubber is in fluid communication with the evaporative emission control canister;
wherein the evaporative emission control canister system is configured to permit sequential contact of the canister adsorbent volume and the scrubber adsorbent volume by fuel vapor; and
wherein the evaporative emission control canister system has a 2-Day Diurnal Breathing Loss (DBL) of less than about 20 mg under the California Bleed Emission Test Protocol (BETP) as of Mar. 22, 2012, when tested under the following test conditions: (i) the total canister adsorbent material volume in the evaporative emission control canister is 2.5 L and at a purge volume of 80 bed volumes; or (ii) the total canister adsorbent material volume in the evaporative emission control canister is 1.9 L and at a purge volume of 135 bed volumes.
2. The evaporative emission control canister system of claim 1 , further comprising a fuel vapor purge tube for connecting the evaporative emission control canister to an engine, a fuel vapor inlet conduit for venting a fuel tank to the evaporative emission control canister, and a vent conduit for venting the evaporative emission control canister to the atmosphere and for admission of purge air to the evaporative emission control canister.
3. The evaporative emission control canister system of claim 1 , wherein the canister adsorbent material is selected from the group consisting of activated carbon, carbon charcoal, zeolites, clays, porous polymers, porous alumina, porous silica, molecular sieves, kaolin, titania, ceria, and combinations thereof.
4. The evaporative emission control canister system of claim 3 , wherein the activated carbon is derived from a material including a member selected from the group consisting of wood, wood dust, wood flour, cotton linters, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, fruit stones, nut shells, nut pits, sawdust, palm, vegetables, synthetic polymer, natural polymer, lignocellulosic material, and combinations thereof.
5. The evaporative emission control canister system of claim 1 , wherein the scrubber adsorbent material comprises a particulate carbon, wherein the particulate carbon has a Brunauer Emmett Teller (BET) surface area of at least about 1300 m 2 /g; and at least one of:
i. a butane affinity of greater than 60% at 5% butane;
ii. a butane affinity of greater than 35% at 0.5% butane;
iii. a micropore volume greater than about 0.2 ml/g and a mesopore volume greater than about 0.5 ml/g.
6. The evaporative emission control canister system of claim 5 , wherein the particulate carbon has an n-butane adsorption capacity of at least about 40 ml/g at about 3 mm Hg n-butane pressure.
7. The evaporative emission control canister system of claim 5 , wherein the particulate carbon has a BET surface area of from about 1300 m 2 /g to about 2500 m 2 /g.
8. The evaporative emission control canister system of claim 5 , wherein the particulate carbon has a micropore volume of from about 0.20 ml/g to about 0.35 ml/g.
9. The evaporative emission control canister system of claim 5 , wherein the particulate carbon has a mesopore volume of from about 0.5 ml/g to about 0.8 ml/g.
10. The evaporative emission control canister system of claim 5 , wherein the particulate carbon has a BET surface area of about 1400 m 2 /gram, a micropore volume of about 0.3 ml/g, and a mesopore volume of about 0.75 ml/g.
11. The evaporative emission control canister system of claim 5 , wherein the bleed emission scrubber comprises a substrate.
12. The evaporative emission control canister system of claim 11 , wherein the substrate is selected from the group consisting of foams, monolithic materials, non-wovens, wovens, sheets, papers, twisted spirals, ribbons, structured media of extruded form, structured media of wound form structured media of folded form, structured media of pleated form, structured media of corrugated form, structured media of pored form, structured media of bonded form, and combinations thereof.
13. The evaporative emission control canister system of claim 11 , wherein the substrate is molded, formed or extruded with a mixture comprising the scrubber adsorbent material.
14. The evaporative emission control canister system of claim 11 , wherein the substrate comprises a coating, wherein the coating comprises the scrubber adsorbent material and a binder.
15. The evaporative emission control canister system of claim 14 , wherein the coating thickness is less than about 500 microns.
16. The evaporative emission control canister system of claim 14 , wherein the binder is present in an amount from about 10% to about 50% by weight relative to the particulate carbon.
17. The evaporative emission control canister system of claim 14 , wherein the binder is an organic polymer.
18. The evaporative emission control canister system of claim 1 , wherein the scrubber adsorbent volume has an effective BWC of from about 0.5 grams/dl to less than 2 grams/dl.
19. The evaporative emission control canister system of claim 1 , wherein the evaporative emission control canister has a canister adsorbent volume of 3.5 L or less, 3.0 L or less, 2.5 L or less, or 2.0 L or less.
20. The evaporative emission control canister system of claim 1 , wherein the evaporative emission control canister system has a 2-Day Diurnal Breathing Loss (DBL) of less than about 10 mg under the California Bleed Emission Test Protocol (BETP) as of Mar. 22, 2012.