Methods and systems for enhancing processing of hydrocarbons in a fluid catalytic cracking unit using plastic
Systems and methods are disclosed for enhancing the processing of hydrocarbons in a FCC unit by introduction of fluidized plastic at one or more locations of the FCC unit. In an embodiment, the method may include passing a coked FCC catalyst from a cyclone of the FCC unit to a regenerator. The method may include introducing at least oxygen and a fluidized plastic into the regenerator. The method may include combusting a combination of the fluidized plastic and a coke from the coked FCC catalyst in the regenerator, thereby to oxidize via the oxygen and produce a regenerated FCC catalyst and a flue gas. The method may include supplying the regenerated FCC catalyst from the regenerator to a riser of the FCC unit to crack the gas oil supplied to the riser of the FCC unit.
1 . A method of processing a gas oil in a fluid catalytic cracking (FCC) unit, the method comprising:
introducing steam and the gas oil into a riser of the FCC unit;
mixing the gas oil and the steam with a catalyst of the FCC unit in the riser;
cracking the gas oil into one or more hydrocarbon products in the FCC unit, thereby to cause one or more surfaces of the catalyst to be at least partially covered by coke so as to define a coked FCC catalyst;
separating the coked FCC catalyst from the one or more hydrocarbon products in the FCC unit;
passing the coked FCC catalyst to a regenerator;
introducing a fluidized plastic into the regenerator; and
combusting a combination of the fluidized plastic and the coke from the coked FCC catalyst in the regenerator, thereby to produce a regenerated FCC catalyst and a flue gas.
2 . The method of claim 1 , wherein combusting the fluidized plastic in the regenerator allows temperature inside the regenerator to be increased without adversely affecting one or more properties of the one or more hydrocarbon products.
3 . The method of claim 1 , wherein combusting the fluidized plastic in the regenerator increases temperature inside the regenerator by at least about 5° F. while maintaining one or more of (a) sulfur specifications of the one or more hydrocarbon products or (b) specification of gasoline in the one or more hydrocarbon products below a pre-selected value.
4 . The method of claim 1 , further comprising introducing the fluidized plastic via an inlet into the regenerator proximate to a bottom portion of the regenerator, and supplying the regenerated FCC catalyst from the regenerator to the riser of the FCC unit.
5 . The method of claim 1 , wherein the fluidized plastic comprises a density of about 0.8 g/cm 3 to about 1.0 g/cm 3 , wherein the fluidized plastic comprises one or more of polypropylene, low-density polyethylene, or high-density polyethylene, wherein the fluidized plastic comprises granules milled to one of a size of about the FCC catalyst or about 1 micrometer to about 350 micrometers, and wherein the fluidized plastic comprises a plastic substantially free from contaminants.
6 . The method of claim 1 , further comprising:
determining, via a controller, a temperature within the regenerator; and
in response to a determination that the temperature within the regenerator is less than a preselected temperature, adjusting, via a flow control device associated with the fluidized plastic and in communication with the controller, an amount of the fluidized plastic introduced into the regenerator to thereby adjust the temperature within the regenerator.
7 . A method of processing a gas oil in a fluid catalytic cracking (FCC) unit, the method comprising:
introducing steam and the gas oil into a riser of the FCC unit;
mixing the gas oil and the steam with a catalyst of the FCC unit when fluidized in the riser;
injecting an amount of fluidized plastic into one or more locations of the FCC unit other than the riser, at one or more time periods to one or more of (a) balance heat within the FCC unit or (b) optimize yield of one or more hydrocarbon products, the fluidized plastic comprising a plurality of granules;
cracking the gas oil into the one or more hydrocarbon products in the FCC unit, thereby to cause one or more surfaces of the catalyst to be at least partially covered by coke so as to define a coked FCC catalyst; and
separating the coked FCC catalyst from the one or more hydrocarbon products in one or more cyclones of the FCC unit.
8 . The method of claim 7 , wherein injection of the fluidized plastic into the one or more locations of the FCC unit comprises injection of the fluidized plastic at one or more of: (a) a regenerator, (b) a reactor, (c) an FCC reactor catalyst bed, or (d) an FCC catalyst stripper, such that adjustment of an amount of fluidized plastic injected at any one of the one or more locations changes one or more of (a) a temperature within the FCC unit and (b) yield selectivity.
9 . The method of claim 8 , wherein injection of the fluidized plastic increases a temperature within the regenerator and thereby increases a temperature of a regenerated FCC catalyst to increase delta coke.
10 . The method of claim 8 , wherein combustion of the fluidized plastic in the regenerator increases temperature inside the regenerator by at least about 5° F. while maintaining a sulfur level in each of the plurality of hydrocarbon products, based on one or more specifications of the plurality of hydrocarbon products produced by processing the gas oil, below a pre-selected value.
11 . The method of claim 8 , wherein the fluidized plastic is introduced in an amount less than about 2 volume percent of the gas oil introduced into the riser.
12 . The method of claim 8 , wherein the fluidized plastic is introduced in an amount ranging from about 1 to about 2 mass percent of the gas oil introduced into the riser.
13 . The method of claim 7 , wherein injection of the fluidized plastic occurs via an existing inlet of the FCC unit, and wherein the existing inlet comprises one or more of a pre-stripping steam inlet, a stripping steam inlet, or a fluffing steam inlet.
14 . The method of claim 7 , wherein the fluidized plastic comprises a density of about 0.8 g/cm 3 to about 1.0 g/cm 3 , wherein the fluidized plastic comprises one or more of polypropylene, low-density polyethylene, or high-density polyethylene, and wherein each of the plurality of granules has a size about 1 micrometer to about 350 micrometers.
15 . The method of claim 7 , wherein injection of the fluidized plastic into the one or more locations of the FCC unit generates selective yields for production of specified hydrocarbon products, and wherein the selective yields for production of specified hydrocarbon products comprises one or more of a reduction of hydrogen generation, an increase in C4 olefinicities, or a reduction in coke yield.
16 . The method of claim 15 , wherein the specified hydrocarbon products include one or more of propylene, light olefins, transportation fuel, or other petrochemical feedstock.
17 . The method of claim 7 , wherein the one or more locations of the FCC unit comprises a regenerator, and further comprising:
passing the coked FCC catalyst to the regenerator;
introducing the fluidized plastic into the regenerator;
combusting a combination of the fluidized plastic and the coke from the coked FCC catalyst in the regenerator, to produce a regenerated FCC catalyst and a flue gas; and
supplying the regenerated FCC catalyst from the regenerator to the riser of the FCC unit.
18 . The method of claim 7 , further comprising:
determining, via a controller responsive to a sensor or analyzer positioned at one or more of within the FCC unit, at an outlet of the FCC unit, or in fluid communication with the outlet of the FCC unit, one or more of a conversion, yield, or selectivity;
in response to a determination that one or more of the conversion, the yield, or the selectivity are less than a preselected value, adjusting the amount of the fluidized plastic injected into the FCC unit at the one or more locations of the FCC unit other than the riser; and
passing the hydrocarbon products to an outlet.
19 . A method of processing a gas oil in a fluid catalytic cracking (FCC) unit, the method comprising:
passing a coked FCC catalyst from a cyclone of the FCC unit to a regenerator;
introducing a fluidized plastic into the regenerator; and
combusting a combination of the fluidized plastic and a coke from the coked FCC catalyst in the regenerator, thereby to produce a regenerated FCC catalyst and a flue gas.
20 . The method of claim 19 , wherein the fluidized plastic comprises a density of about 0.8 g/cm 3 to about 1.0 g/cm 3 , wherein the fluidized plastic comprises one or more of polypropylene, low-density polyethylene, or high-density polyethylene, wherein the fluidized plastic comprises granules milled to one of a size of about a FCC catalyst or about 1 micrometer to about 350 micrometers, and wherein the fluidized plastic comprises a plastic substantially free from contaminants.
21 . The method of claim 20 , wherein introduction of the fluidized plastic into the regenerator occurs at one or more inlets of the regenerator, and the method further comprising supplying the regenerated FCC catalyst from the regenerator to a riser of the FCC unit, thereby to crack the gas oil supplied to the riser of the FCC unit.
22 . The method of claim 19 , further comprising:
determining a temperature within the regenerator;
determining a temperature within a riser of the FCC unit; and
in response to a determination that one or more of (a) the temperature within the regenerator or (b) the temperature within the riser of the FCC unit exceeds or falls below a corresponding threshold range, one or more of:
adjusting an amount of fluidized plastic introduced into the regenerator,
adjusting an amount of regenerated FCC catalyst supplied to the riser, or
introducing a second amount of fluidized plastic into one or more inlets of a reactor of the FCC unit.
23 . The method of claim 19 , further comprising:
determining a yield of a specified hydrocarbon product produced via the FCC unit; and
in response to a determination that the yield falls below a selected threshold, one or more:
adjusting an amount of fluidized plastic introduced into the regenerator,
adjusting an amount of regenerated FCC catalyst supplied to a riser, or
introducing a second amount of fluidized plastic into one or more locations of a reactor of the FCC unit.
24 . The method of claim 19 , further comprising:
prior to introduction of the fluidized plastic into the regenerator, milling the plastic to a selected size, wherein the selected size comprises one or more of a size about a size of FCC catalyst or about 1 micrometer to about 350 micrometers.
25 . The method of claim 19 , wherein the fluidized plastic comprises plastic granules milled from one or more of plastic waste or post-consumer plastic waste.
26 . A system for processing a gas oil in a fluid catalytic cracking (FCC) unit, the system comprising:
a riser having a first inlet to receive a gas oil stream, a second inlet in fluid communication with steam and a first portion of fluidized plastic, and a third inlet to receive a catalyst, the riser positioned to facilitate mixing and catalytic cracking of the gas oil stream in presence of the steam and the catalyst, thereby to produce a plurality of hydrocarbon products and coked FCC catalyst;
a reactor having (i) a FCC reaction zone in fluid communication with a portion of the riser and configured to continue to crack the gas oil stream in presence of the steam and the FCC catalyst, thereby generate the plurality of hydrocarbon products and more of the coked FCC catalyst, (ii) a separation zone to separate the plurality of hydrocarbon products from the coked FCC catalyst, and (iii) a first outlet stream to transport the plurality of hydrocarbon products to a fractionation zone, thereby to separate the plurality of hydrocarbon products into one or more of propylene, isobutene, butylenes, gasoline, distillate, diesel fuel, heating oil, slurry oil, or wet gas; and
a regenerator having a first inlet stream in fluid communication with a second outlet stream of the reactor to receive the coked FCC catalyst, the regenerator having a second inlet stream to receive at least oxygen and a third inlet stream in fluid communication with and to receive a second portion of fluidized plastic, a third outlet stream in fluid communication with the third inlet of the riser to supply a regenerated FCC catalyst to the riser, and a fourth outlet stream positioned to discharge a flue gas containing one or more of nitrogen, nitrogen oxides, carbon dioxide, carbon monoxide, or water vapor, the regenerator operated to combust coke on the coked FCC catalyst, the first portion of fluidized plastic, and the second portion of fluidized plastic, thereby to produce the regenerated FCC catalyst and the flue gas.
27 . The system of claim 26 , further comprising a stripping zone connected to and in fluid communication with the second outlet stream and the regenerator, the stripping zone being operated to remove adsorbed and entrained hydrocarbons from the coked FCC catalyst prior to supplying the coked FCC catalyst to the regenerator.
28 . The system of claim 26 , further comprising:
a bottom portion of the regenerator; and
a bed of the coked FCC catalyst positioned inside the regenerator,
wherein the second portion of fluidized plastic is introduced proximate to or into one or more of the bottom portion of the regenerator or the bed of the coked FCC catalyst positioned inside the regenerator.
29 . The system of claim 26 , further comprising:
a temperature sensor positioned within the regenerator to measure a temperature within the regenerator; and
a controller in signal communication with the temperature sensor, the controller configured to, in response to a determination that the temperature within the regenerator is less than a preselected temperature, adjust an amount of the fluidize plastic supplied to the regenerator.