CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application Serial No. 62/318,933 filed April 6, 2016, the entire disclosure of which is hereby incorporated by reference.

BACKGROUND

[0002] The present disclosure generally relates to snorkel inlets for cyclones. More specifically, in certain embodiments the present disclosure relates to cyclones comprising snorkel inlets useful in separation vessels and associated methods and systems.

[0003] In a typical Fluid Catalytic Cracking Unit (FCCU), finely divided regenerated catalyst is drawn from a regenerator through a regenerator standpipe and contacts a hydrocarbon feedstock in a lower portion of a reactor riser. Hydrocarbon feedstock and steam enter the riser through feed nozzles. The mixture of feedstock, steam and regenerated catalyst, which has a temperature in the range of from about 200°C to about 700°C, passes up through the riser reactor, converting the feed into lighter products while a coke layer deposits on the surface of the catalyst, temporarily deactivating the catalyst.

[0004] The hydrocarbon vapors and catalyst from the top of the riser are then passed through cyclones to separate spent catalyst from the hydrocarbon vapor product stream. The spent catalyst enters a stripper where steam is introduced to remove hydrocarbon products from the catalyst. The spent catalyst then passes through a spent catalyst standpipe to enter the regenerator where, in the presence of gas and at a temperature of from about 620°C to about 760°C, the coke layer on the spent catalyst is combusted to restore the catalyst activity. Regeneration is typically performed in a vessel comprising a fluidized bed and one or more cyclones.

[0005] Currently, cyclone loadings are designed to manage a full bed catalyst entrainment rate. However, as entrainment rate is proportional to the amount of wear of such cyclones, cyclones with high entrainment rates are susceptible to high rates of wear.

[0006] It is desirable to develop a way of reducing the cyclone loading rate in separation vessels to extend the life of cyclones. SUMMARY

[0007] The present disclosure generally relates to snorkel inlets for cyclones. More specifically, in certain embodiments the present disclosure relates to cyclones comprising snorkel inlets useful in separation vessels and associated methods and systems.

[0008] In one embodiment, the present disclosure provides a cyclone comprising: a cyclone body, a conical section connected to the cyclone body, and a snorkel inlet connected to the cyclone body.

[0009] In another embodiment, the present disclosure provides a vessel comprising: a fluidized bed and a primary cyclone disposed within the vessel, wherein the primary cyclone comprises a cyclone body, a conical section connected to the cyclone body, and a snorkel inlet connected to the cyclone body.

[0010] In another embodiment, the present disclosure provides a method comprising: providing a separation vessel, wherein the separation vessel comprises a fluidized bed and a primary cyclone disposed within the vessel, wherein the primary cyclone comprises a cyclone body, a conical section connected to the cyclone body, and a snorkel inlet connected to the cyclone body and introducing an air/catalyst feed into the separation vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings.

[0012] Figure 1 illustrates a cross sectional view of a cyclone comprising a snorkel inlet in accordance with certain embodiments of the present disclosure.

[0013] Figure 2 illustrates a cross sectional view of a vessel comprising a cyclone with a snorkel inlet in accordance with certain embodiments of the present disclosure.

[0014] Figure 3 is an illustration of the estimated erosion in a conventional cyclone.

[0015] Figure 4 is an illustration of the estimated erosion in a cyclone in accordance with certain embodiments of the present disclosure.

[0016] The features and advantages of the present disclosure will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the disclosure. DETAILED DESCRIPTION

[0017] The description that follows includes exemplary apparatuses, methods, techniques, and/or instruction sequences that embody techniques of the inventive subject matter. However, it is understood that the described embodiments may be practiced without these specific details.

[0018] The present disclosure generally relates to snorkel inlets for cyclones. More specifically, in certain embodiments the present disclosure relates to cyclones comprising snorkel inlets useful in separation vessels and associated methods and systems.

[0019] In certain embodiments, the cyclones described herein may have an inlet with a higher elevation than conventional cyclones. In certain embodiments, the cyclones described herein may comprise snorkel inlets that allow for a reduction in solids loading compared to conventional cyclones. By decreasing the solids loading, that erosion rate of the cyclone may be reduced allowing for a longer service life, less repair work scope during turn around, and lower opacity. In certain embodiments, the cyclones described herein may have longer cycle lengths than conventional cyclones.

[0020] Referring now to Figure 1, Figure 1 illustrates cyclone 100. In certain embodiments, cyclone 100 may be any conventional cyclone used in FCC separators. In certain embodiments, cyclone 100 may be a primary cyclone. Examples of conventional primary cyclones are described in in U.S. Patent Nos. 7,250,140, 7,160,518, 7,179,428, 6,979,358, 7,101,516, 7,077,949, 6,723,227, and 6,846,463, the entireties of which are hereby incorporated by reference. In certain embodiments, cyclone 100 may be constructed out of carbon steel. In certain embodiments, cyclone 100 may be constructed out of carbon steel with an erosion resistance coating, ceramics, and/or ceramets.

[0021] In certain embodiments, cyclone 100 may comprise cyclone body 110, conical section 120, dipleg 130, and snorkel inlet 140.

[0022] In certain embodiments, cyclone body 110 may comprise any conventional cyclone body used in FCC separators. In certain embodiments, cyclone body 110 may be a hollow cylindrical structure defining an interior 101. In certain embodiments, cyclone body 110 may be constructed out of carbon steel. In certain embodiments, cyclone body 110 may be constructed out of carbon steel with an erosion resistance coating, ceramics, and/or ceramets. In certain embodiments, cyclone body may comprise an inlet 111 and outlet 112. In certain embodiments, cyclone body 110 may comprise a top surface 113 and an open bottom 114. In certain embodiments, inlet 111 may be located on a sidewall surface 115 of cyclone body 110. In certain embodiments, outlet 112 may be located on top surface 113. In certain embodiments, a gas outlet tube 116 may extend into interior 101 through outlet 112.

[0023] In certain embodiments, cyclone body 110 may have a diameter in the range of from 1 foot to 10 feet. In certain embodiments, cyclone body 110 may have a diameter in the range of from 3 feet to 6 feet. In certain embodiments, cyclone body 110 may have a length in the range of from 1 foot to 10 feet. In certain embodiments, cyclone body 110 may have a length in the range of from 3 feet to 6 feet.

[0024] In certain embodiments, conical section 120 may comprise any conventional conical sections used in FCC separators. In certain embodiments, conical section 120 may be connected to, or be a part of, cyclone body 110. In certain embodiments, conical section

120 may be constructed out of carbon steel. In certain embodiments, conical section 120 may be constructed out of carbon steel with an erosion resistance coating, ceramics, and/or ceramets. In certain embodiments, conical section 120 may have an open top 121 and an open bottom 122. In certain embodiments, conical section 120 may define an interior 102.

[0025] In certain embodiments, conical section 120 may have a diameter at open top

121 in the range of from 1 foot to 10 feet. In certain embodiments, conical section 120 may have a diameter at open top 121 in the range of from 3 feet to 6 feet. In certain embodiments, conical section 120 may have a diameter at open bottom 122 in the range of from 1 foot to 5 feet. In certain embodiments, conical section 120 may have a diameter at open bottom 122 in the range of from 2 feet to 3 feet. In certain embodiments, conical section 120 may have a length in the range of from 1 foot to 10 feet. In certain embodiments, conical section 120 may have a length in the range of from 3 feet to 6 feet. In certain embodiments, conical section 120 may have a taper in the range of from 30 degrees to 75 degrees.

[0026] In certain embodiments, dipleg 130 may comprise any conventional dipleg used in FCC separators. In certain embodiments, dipleg 130 may be connected to, or be a part of, conical section 120 and/or cyclone body 110. In certain embodiments, dipleg 130 may have an open top 131 and an open bottom 132. In certain embodiments, dipleg 130 may be a hollow cylindrical structure defining an interior 103. In certain embodiments, dipleg 130 may be constructed out of carbon steel. In certain embodiments, dipleg 130 may be constructed out of carbon steel with an erosion resistance coating, ceramics, and/or ceramets.

[0027] In certain embodiments, dip leg 130 may have a diameter in the range of from 1 foot to 5 feet. In certain embodiments, dip leg 130 may have a diameter in the range of from 2 feet to 3 feet. In certain embodiments, dipleg 130 may have a length in the range of from 1 foot to 40 feet. In certain embodiments, dipleg 130 may have a length in the range of from 5 feet to 10 feet. In certain embodiments, cyclone 100 may be a cyclone that does not have a dipleg.

[0028] In certain embodiments, snorkel inlet 140 may comprise any inlet designed with an upturned intake 144. In certain embodiments, the upturned intake may be located at or above cyclone body 110. In certain embodiments, snorkel inlet 140 may be constructed out of carbon steel. In certain embodiments, snorkel inlet 140 may be constructed out of carbon steel with an erosion resistance coating, ceramics, and/or ceramets. In certain embodiments, snorkel inlet 140 may be a tubular structure. In certain embodiments, snorkel inlet 140 have a circular cross sectional geometry. In other embodiments, snorkel inlet 140 may have a non-circular cross sectional geometry. In certain embodiments, snorkel inlet 140 may have a rectangular cross sectional geometry.

[0029] In certain embodiments, snorkel inlet 140 may have the same cross sectional area of conventional cyclone inlets. In certain embodiments, snorkel inlet 140 may have a constant cross sectional area. In other embodiments, snorkel inlet 140 may have a varying cross sectional area and/or be tapered. For example in certain embodiments, snorkel inlet 140 may have a varying cross sectional area with the largest cross sectional area at upturned intake 144.

[0030] In certain embodiments, snorkel inlet 140 may comprise horizontal section 141, curved section 142, and vertical section 143. In certain embodiments, horizontal section 141, curved section 142, and vertical section 143 all may have the same cross sectional areas. In other embodiments, horizontal section 141, curved or angled section 142, and vertical section 143 may have different cross sectional areas. For example, in certain embodiments, curved section 142 and vertical section 143 both may have a larger cross sectional area than horizontal section 141.

[0031] In certain embodiments, a central axis of horizontal section 141 may be perpendicular with a central axis of cyclone body 110. In certain embodiments, a central axis of horizontal section 141 may be inclined or declined an amount in the range of from 0° to 15° with respect to a central axis of cyclone body 110. In certain embodiments, a central axis of vertical section 143 may be perpendicular with a central axis of horizontal section 141. In certain embodiments, a central axis of vertical section 143 may be inclined or declined an amount in the range of from 45° to 95° with respect to a central axis of horizontal section 141. In certain embodiments, upturned intake 144 may be located at the end of vertical section 143.

[0032] In certain embodiments, the present disclosure provides a vessel comprising: a fluidized bed and one or more cyclones, wherein at least one of the one or more cyclones comprise a snorkel inlet. Referring now to Figure 2, Figure 2 illustrates a cross sectional view of a vessel 1000 comprising one or more cyclones 1100.

[0033] In certain embodiments, vessel 1000 may comprise any conventional vessel used in the separation of solids from gases. In certain embodiments, vessel 1000 may comprise a regenerator vessel or any other vessel comprising a fluidized bed. In certain embodiments, vessel 1000 may comprise any conventional separation chamber used in the separation of FCC catalyst from gasses.

[0034] In certain embodiments, vessel 1000 may comprise housing 1001, gas/solids inlet 1002 tube, solids outlet tube 1003, and gas outlet tube 1004.

[0035] In certain embodiments, housing 1001 may comprise any conventional housing used in conventional separation vessels. In certain embodiments, housing 1001 may be constructed of metals, metal alloys, and/or ceramics and may be lined with erosion resistant coatings or ceramic lining. In certain embodiments, housing 1001 may have a cylindrical shape with an inner diameter and an inner length. In certain embodiments, housing 1001 may define a hollow interior 1005.

[0036] In certain embodiments, housing 1001 may have an inner diameter in the range of from 1 foot to 60 feet. In certain embodiments, housing 1001 may have an inner diameter in the range of from 10 feet to 20 feet. In certain embodiments, housing 1001 may have an inner length in the range of from 5 feet to 250 feet. In certain embodiments, housing 1001 may have an inner length in the range of from 10 feet to 100 feet.

[0037] In certain embodiments, gas-solids inlet 1002 may permit the flow of gas and solids into vessel 1000. In certain embodiments, gas-solids inlet 1002 may be sized to allow the flow of gas and solids into vessel 1000 at gas flow rates in the range of from 10,000 SCFM to 500,000 SCFM. In certain embodiments, gas/solids inlet tube 1002 may be sized to allow the flow of gas and solids into vessel 1000 at gas flow rates in the range of from 20,000 SCFM to 250,000 SCFM. In certain embodiments, gas/solids inlet tube 1002 may be sized to allow for the formation of a fluidized bed 1300 within vessel 1000.

[0038] In certain embodiments, gas/solids inlet tube 1002 may be connected to a distributor 1006. In certain embodiments, distributor 1006 may comprise any conventional distributor used in FCC separation vessels.

[0039] In certain embodiments, solids outlet tube 1003 may be positioned along a bottom of housing 1001. In certain embodiments, solids outlet tube 1003 may permit the flow solids out of vessel 1000. In certain embodiments, gas outlet tube 1004 may be positioned along a top of housing 1001. In certain embodiments, gas outlet tube 1004 may permit the flow of gas out of vessel 1000.

[0040] In certain embodiments, the one or more cyclones 1100 may comprise a combination of primary cyclones and/or secondary cyclones. In certain embodiments, not shown in Figure 2, the one or more cyclones 1100 may consist of one or more primary cyclones. In certain embodiments, as shown in Figure 2, the one or more cyclones 1100 may comprise one primary cyclone 1110 and one secondary cyclone 1120. In other embodiments, the one or more cyclones 1100 may comprise multiple primary cyclones 1110 and multiple secondary cyclones 1120.

[0041] In certain embodiments, primary cyclone 1110 may comprise any conventional primary cyclone used in FCC separators. In certain embodiments, secondary cyclone 1120 may comprise any conventional secondary cyclone used in FCC separators.

[0042] In certain embodiments, primary cyclone 1110 may comprise any combination of features discussed above with respect to cyclone 100. In certain embodiments, primary cyclone 1110 may comprise cyclone body 1210, conical section 1220, dipleg 1230, and snorkel inlet 1240.

[0043] In certain embodiments, cyclone body 1210 may comprise any combination of features discussed above with respect to cyclone body 110. In certain embodiments, cyclone body 1210 may comprise inlet 1211, outlet 1212, top surface 1213, open bottom 1214, sidewall surface 1215, and gas outlet tube 1216. In certain embodiments, gas outlet tube 1216 may be connected to crossover 1217. In certain embodiments, cyclone body 1210 may define interior 1201.

[0044] In certain embodiments, conical section 1220 may comprise any combination of features discussed above with respect to conical section 120. In certain embodiments, conical section 1220 may comprise open top 1221 and open bottom 1222. In certain embodiments, conical section 1220 may define interior 1202.

[0045] In certain embodiments, dipleg 1230 may comprise any combination of features discussed above with respect to dipleg 130. In certain embodiments, dipleg 1230 may comprise open top 1231 and open bottom 1232. In certain embodiments, dipleg 1230 may define interior 1203.

[0046] In certain embodiments, snorkel inlet 1240 may comprise any combination of features discussed above with respect to snorkel inlet 140. In certain embodiments, snorkel inlet 1240 may comprise horizontal section 1241, curved section 1242, vertical section 1243, and upturned intake 1244.

[0047] In certain embodiments, primary cyclone 1110 may be configured and positioned within vessel 1000 such that only a portion of snorkel inlet 1240 is above cyclone body 1210. In certain embodiments, primary cyclone 1110 may be positioned within vessel 1000 such that a portion of vertical portion 1243 of snorkel inlet 1240 is above top surface 1213 of cyclone body 1210 while horizontal portion 1241 is below top surface 1213 of cyclone body 1210. In certain embodiments, primary cyclone 1110 may be positioned within vessel 1000 such that upturned intake 1244 is above top surface 1213 of cyclone body 1210 while horizontal portion 1241 is below top surface 1213 of cyclone body 1210. In certain embodiments, primary cyclone 1110 may be positioned within vessel 1000 such that upturned intake 1244 is a maximum vertical distance above fluidized bed 2300 that still allows for gas and solids to enter primary cyclone 1110. In certain embodiments, primary cyclone 1110 may be positioned within vessel 100 such that gas and solids may enter primary cyclone 1110 at a flow rate in the range of from 100,000 lbs/hour to 1,000,000 lbs/hour of flue gas.

[0048] In certain embodiments, dipleg 1230 may extend into fluidized bed 2300. In other embodiments, dipleg 1230 may not extend into fluidized bed 2300. In certain embodiments, dipleg 1230 may permit a mixture of gas and solids to exit primary cyclone

1110 and return hollow interior 1005.

[0049] In certain embodiments, secondary cyclone 1120 may comprise inlet 1121, cyclone body 1122, conical section 1123, and dipleg 1124, and outlet 1125.

[0050] In certain embodiments, secondary cyclone 1120 may be positioned within vessel 1000 such that inlet 1121 allows a mixture of gas and solids from primary cyclone

1110 to enter into cyclone body 1122 through crossover 1217.

[0051] In certain embodiments, cyclone body 1122 may comprise any conventional cyclone body. In certain embodiments, conical section 1123 may comprise any conventional conical section.

[0052] In certain embodiments, dipleg 1124 may comprise any conventional dipleg. In certain embodiments, dipleg 1124 may extend into fluidized bed 1300. In other embodiments, dipleg 1124 may not extend into fluidized bed 2300. In certain embodiments, dipleg 1124 may permit a mixture of gas and solids to exit secondary cyclone 1120 and return to hollow interior 1005.

[0053] In certain embodiments, outlet 1125 may be positioned at a top of secondary cyclone 1120. In certain embodiments, a gas outlet tube 1216 may extend into interior 1201 through outlet 1125. In certain embodiments, gas outlet tube 1216 may allow a mixture of gas and solids to exit secondary cyclone 1120 and exit vessel 1000. In certain embodiments, the mixture of gas and solids exiting secondary cyclone 1120 through gas outlet tube 1216 may have a volume fraction of solids in the range of from 0.001 to 0.01.

[0054] In certain embodiments, the present disclosure provides a method comprising: providing a separation vessel, wherein the separation vessel comprises a fluidized bed and a primary cyclone, wherein the primary cyclone comprises a cyclone body, a conical section, and a snorkel inlet and introducing an air/catalyst feed into the separation vessel.

[0055] In certain embodiments, the vessel may comprise any combination of features discussed above with respect to vessel 1000. In certain embodiments, the vessel may further comprise a secondary cyclone. In certain embodiments, the vessel may comprise one or more primary cyclones. In certain embodiments, the one or more primary cyclones may comprise any combination of features discussed above with respect to primary cyclone 1110. In certain embodiments, the vessel may comprise one or more secondary cyclones. In certain embodiments, the one or more secondary cyclones may comprise any combination of features discussed above with respect to secondary cyclone 1120.

[0056] In certain embodiments, introducing an air/catalyst feed into the vessel may comprise introducing a flow of gas and solids into the vessel at a gas flow rate in the range of from 10,000 SCFM to 500,000 SCFM.

[0057] In certain embodiments, the method may further comprise removing solids from the air/catalyst feed. In certain embodiments, the method may further comprise allowing a mixture of gas and solids to enter into the one or more primary cyclones. In certain embodiments, the mixture of gas and solids may enter into the one or more primary cyclones by flowing through a snorkel inlet of the primary cyclone. In certain embodiments, the volume fraction of solids in the mixture introduced into the one or more primary cyclones may be a volume fraction in the range of from 0.01 to 0.3. In certain embodiments, the method may further comprise allowing a mixture of gas and solids to exit the one or more primary cyclones through one or more diplegs. In certain embodiments, the volume fraction of solids in the mixture exciting the one or more primary cyclones may be a volume fraction in the range of form 0.2 to 0.6.

[0058] In certain embodiments, the method may further comprise allowing a mixture of gas and solids to exit the one or more primary cyclones through an outlet and enter into one or more secondary cyclones. In certain embodiments, the volume fraction of solids in the mixture introduced into the one or more secondary cyclones may have a loading that is in the range of from 1% to 20% of the loading of the mixture that is introduced into the one or more primary cyclones.

[0059] In certain embodiments, the method may further comprise allowing a mixture of gas and solids to exit the one or more secondary cyclones through one or more diplegs. In certain embodiments, the volume fraction of solids in the mixture exiting the one or more secondary cyclones through the one or more diplegs may be a volume fraction in the range of form 0.2 to 0.6.

[0060] In certain embodiments, the method may further comprise allowing a mixture of gas and solids to exit the one or more secondary cyclones through one or more gas outlet tubes. In certain embodiments, the volume fraction of solids in the mixture exiting the one or more secondary cyclones through the one or more gas outlet tubes may have a loading that is in the range of from 1% to 20% of the loading of the mixture that is introduced into the one or more primary cyclones.

[0061] To facilitate a better understanding of the present invention, the following examples of specific embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the invention.

EXAMPLES

Example 1

[0062] The effect that a snorkel inlet has on cyclone erosion was measured by simulating a flow through a conventional cyclone system comprising a primary cyclone, a secondary cyclone, and a gas distributor and a flow through a cyclone system comprising a primary cyclone with a snorkel inlet, a secondary cyclone, and a gas distributor and comparing the estimated erosion between the two systems.

[0063] In the simulation, a mixture of an FCC catalyst and gas was passed through the conventional cyclone system at inlet gas velocity ranging between 45 ft/s and 75 ft s with the solids loading rate up to 7,235,000 lbs/h to a single cyclone pair. The simulated erosive wear pattern of the primary and secondary cyclone was based upon the particle momentum transfer to the cyclone wall and the angle of impact. Figure 3 illustrates the erosive wear pattern for the conventional cyclone system.

[0064] A snorkel inlet in accordance to certain embodiments of the present disclosure was then installed onto the primary cyclone. The same mixture of the FCC catalyst and gas was then passed through the cyclone system at inlet gas velocity ranging between 45 ft/s and 75 ft/s and solids loading rate up to 7,235,000 lbs/h to a single cyclone pair. The simulated erosive wear pattern of the primary cyclone and the secondary cyclone is based upon the particle momentum transfer to the cyclone wall and the angle of impact. Figure 4 illustrates the erosive wear pattern for this cyclone system.

[0065] As can be seen by contrasting Figures 3 with Figure 4, the cyclone system comprising a snorkel inlet experienced a reduced amount of erosive wear than the conventional primary cyclone.

[0066] While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions and improvements are possible.

[0067] Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter.