EP1201729A2 - Fluid catalytic cracking regenerator with reduced NOx emissions - Google Patents
Fluid catalytic cracking regenerator with reduced NOx emissions Download PDFInfo
- Publication number
- EP1201729A2 EP1201729A2 EP01309166A EP01309166A EP1201729A2 EP 1201729 A2 EP1201729 A2 EP 1201729A2 EP 01309166 A EP01309166 A EP 01309166A EP 01309166 A EP01309166 A EP 01309166A EP 1201729 A2 EP1201729 A2 EP 1201729A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- nitrogen
- oxygen
- boiler
- regenerator
- carbon monoxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000004231 fluid catalytic cracking Methods 0.000 title claims description 4
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 68
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 60
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910002091 carbon monoxide Inorganic materials 0.000 claims abstract description 40
- 239000007789 gas Substances 0.000 claims abstract description 39
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000001301 oxygen Substances 0.000 claims abstract description 32
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 32
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 29
- 239000002737 fuel gas Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 17
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 6
- 230000002401 inhibitory effect Effects 0.000 claims abstract description 4
- 238000002485 combustion reaction Methods 0.000 claims description 23
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 19
- 239000001569 carbon dioxide Substances 0.000 claims description 13
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 13
- 239000003546 flue gas Substances 0.000 claims description 8
- 239000003054 catalyst Substances 0.000 description 33
- 239000000571 coke Substances 0.000 description 19
- 239000004215 Carbon black (E152) Substances 0.000 description 9
- 229930195733 hydrocarbon Natural products 0.000 description 9
- 150000002430 hydrocarbons Chemical class 0.000 description 9
- 238000005336 cracking Methods 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 229910052815 sulfur oxide Inorganic materials 0.000 description 6
- 230000008929 regeneration Effects 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 3
- 239000000567 combustion gas Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical class S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 238000010793 Steam injection (oil industry) Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000004523 catalytic cracking Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010344 co-firing Methods 0.000 description 1
- 150000001923 cyclic compounds Chemical class 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910017464 nitrogen compound Inorganic materials 0.000 description 1
- 150000002830 nitrogen compounds Chemical class 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 150000002831 nitrogen free-radicals Chemical class 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000003716 rejuvenation Effects 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
- C10G11/18—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "fluidised-bed" technique
- C10G11/185—Energy recovery from regenerator effluent gases
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
- C10G11/18—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "fluidised-bed" technique
- C10G11/182—Regeneration
Definitions
- the present invention provides for a fluid catalytic cracker (FCC) regeneration process having low NO x emissions.
- FCC fluid catalytic cracker
- the present invention more specifically provides for reducing the NO x emissions from the carbon monoxide boiler downstream of the FCC regeneration unit.
- hydrocarbon feedstock is injected into the riser section of a hydrocarbon cracking reactor, where it cracks into lighter, valuable products on contacting hot catalyst circulated to the riser-reactor from a catalyst regenerator vessel.
- the catalyst gets covered with coke deposits.
- the catalyst and hydrocarbon vapors are carried up the riser to the disengagement section of the reactor, where they are separated. Subsequently, the catalyst flows into the stripping section, where the hydrocarbon vapors entrained with the catalyst are stripped by steam injection, and the stripped catalyst flows through a spent catalyst standpipe and into the catalyst regenerator vessel.
- the catalyst is regenerated by introducing air into the regenerator vessel to burn coke off the catalyst, thereby rejuvenating it.
- the coke combustion reactions are highly exothermic and heat the catalyst.
- the hot, reactivated catalyst flows through the regenerated catalyst standpipe back to the riser to complete the catalyst cycle.
- the coke combustion exhaust gas stream rises to the top of the regenerator and leaves the regenerator through the regenerator flue.
- the exhaust gas contains nitrogen and carbon dioxide (CO 2 ), and generally also contains carbon monoxide (CO), oxygen, sulfur oxides (SO x ), nitrogen oxides (NO x ) and reduced nitrogen species, such as ammonia.
- the catalyst regenerator may be operated in complete combustion mode, which has now become the standard combustion mode, or in partial CO combustion mode.
- complete combustion operation the coke on the catalyst is completely burned to CO 2 . This is typically accomplished by conducting the regeneration in the presence of excess oxygen, provided in the form of excess air.
- the exhaust gas from complete combustion operations comprises primarily CO 2 , nitrogen and excess oxygen, but also contains NO x and SO x .
- the catalyst regenerator In partial carbon monoxide combustion mode operation, the catalyst regenerator is operated with insufficient air to burn all of the coke in the catalyst to CO 2 , consequently the coke is combusted to a mixture of CO and CO 2 .
- the CO is oxidized to CO 2 in a downstream CO boiler.
- the effluent from the CO boiler comprises primarily CO 2 and nitrogen, but also contains NO x and SO x .
- a method for inhibiting the formation of nitrogen oxides in a carbon monoxide boiler using fuel gas to burn the carbon monoxide downstream of a fluid catalytic cracking regenerator comprising introducing an oxygen-enriched gas stream into said boiler.
- the FCC regenerator operating in partial combustion mode typically is at a temperature of 1240°F to 1400°F and a pressure of 15 psig to 50 psig.
- Oxygen-enriched air is preferably used as the combustion gas with oxygen levels preferably higher than 24% and more preferably higher than 27% by volume is employed.
- the flue gas typically has a CO content between 15% and 1% by volume.
- the downstream boiler or carbon monoxide boiler is used for combusting unconverted carbon monoxide and typically also waste heat recovery.
- the present invention replaces the air that is used for combustion with oxygen-enriched gas containing at least 24% but preferably more than 25% oxygen.
- Fuel gas is added to stabilize the burning of the carbon monoxide due to the low adiabatic flame temperature of CO combustion and low concentration of CO in the FCC flue gas stream.
- the use of the oxygen-enriched gas being added to the carbon monoxide burner results in less fuel gas used to ensure a stable flame.
- the present invention also further relates to a method for inhibiting the formation of NO x in a carbon monoxide boiler downstream of an FCC regenerator comprising introducing a nitrogen-enriched gas stream into said boiler in conjunction with the oxygen-enriched gas stream.
- the nitrogen-enriched gas stream preferably contains at least 80% nitrogen.
- the nitrogen-enriched gas may be obtained from any convenient source and can be fed through a separate feed at the same time as the oxygen-enriched gas is fed to the carbon monoxide boiler.
- a nitrogen-enriched air stream is co-fired around the fuel gas ports in the boiler.
- This stream which can be the byproduct stream of an oxygen generator will further reduce the maximum flame temperature as well as quenching of NO x precursors by the atomic nitrogen radicals generated around the fuel gas flame.
- hydrocarbon cracking catalyst regenerator 2 is provided externally with spent catalyst transport line 4, regenerated catalyst transport line 6, oxygen-containing gas supply line 8, and exhaust gas line 10.
- a combustion zone, designated generally as 12, and a reducing zone, designated generally as 14, are located in the lower and upper regions, respectively, of the regenerator 2.
- Feed line 16 connects supply line 8 to the center of gas distributor 18.
- Distributor 18 is fitted with nozzles 20.
- Combustion zone 12 is the area within the regenerator 2 where combustion of the coke takes place. Since combustion of the coke is effected by contact of the oxygen with the hot coke, combustion zone 12 is defined by the oxygen entering the regenerator 2. The nozzles 20 may be directed downwards thusly enlarge the combustion zone 12.
- Exhaust gas line 10 connects the upper region of the regenerator 2 with the carbon monoxide boiler 22, which in turn is fitted with a vent line 24.
- the carbon monoxide boiler is described in more detail regarding the description of Fig. 2.
- spent hydrocarbon cracking catalyst is transferred from a hydrocarbon cracking reactor (not shown) to regenerator 4 via spent catalyst line 4.
- the spent catalyst swirls around the interior of regenerator 2 in a tangential motion.
- a dilute fluidized bed forms in the upper part of regenerator 2 and a dense fluidized bed forms in the lower region of the regenerator.
- the total oxygen content of the gas entering regenerator 2 is insufficient to convert all of the coke to carbon dioxide. Accordingly, the regenerator 2 is said to be operating in partial combustion mode.
- the incoming feed gas is rich enough in oxygen to cause substantial quantities of the reduced nitrogen in the coke compounds to convert to nitrogen oxides. If the incoming feed gas were less concentrated in oxygen, some of the coke nitrogen would be converted to reduced nitrogen compounds, such as ammonia.
- the combustion gases rapidly rise to the top of the regenerator 2 and enter reducing zone 14, wherein the concentration of carbon monoxide is sufficiently high to create a reducing environment.
- Much of the nitrogen oxides in the exhaust gas are converted to elemental nitrogen as the gas passes through reducing zone 14.
- this exhaust gas containing carbon monoxide, carbon dioxide, nitrogen, oxygen is directed through exhaust gas line 10 into the carbon monoxide boiler 22.
- Fuel gas is added to the boiler 22 via fuel gas line 26.
- the fuel gas will stabilize the burning of the carbon monoxide due to its low adiabatic flame temperature, and the low, roughly 8 to 10%, concentration of carbon monoxide in the FCC flue gas exhaust stream.
- the fuel gas burns at a temperature of about 800° to 1500°C.
- a gas stream containing at least 24% by volume of oxygen is added to the carbon monoxide boiler via line 28.
- the amount of fuel gas consequently being inputted through line 26 can be lowered as a stable flame depicted as 32 is produced.
- the peak temperature of the areas of the flame rich in fuel gas is reduced. This reduces the production of NO x compounds via the prompt and thermal NO x mechanisms.
- nitrogen-enriched gas containing at least 80% nitrogen is simultaneously along with the oxygen-enriched gas added to the carbon monoxide boiler 22 via line 30.
- This stream which may come from the byproduct stream of the oxygen generator (not shown) will co-fire around the fuel gas port of line 26.
- This co-firing is enabled in part by the use of the oxygen-enriched gas for carbon monoxide production and will enable the minimization of the maximum flame temperature.
- NO x precursors are also quenched as a result of the nitrogen radicals, N•, generated around the fuel gas flame.
- the NO x reduced gas is primarily composed of carbon dioxide and is removed from the boiler via vent line 24.
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Catalysts (AREA)
Abstract
Description
The flue gas typically has a CO content between 15% and 1% by volume.
- Fig. 1 is a cross sectional view of a catalyst regeneration vessel of an FCC plant.
- Fig. 2 is a cross sectional view of a carbon monoxide boiler.
Claims (10)
- A method for inhibiting the formation of nitrogen oxides in a carbon monoxide boiler using fuel gas to burn the carbon monoxide downstream of a fluid catalytic cracking regenerator comprising introducing an oxygen-enriched gas stream into said boiler.
- A method as claimed in claim 1, wherein said oxygen-enriched gas stream comprises at least 24% by volume of oxygen.
- A method as claimed in claim 2, wherein said oxygen-enriched gas stream comprises more than 25% by volume of oxygen.
- A method as claimed in any one of the preceding claims, wherein the flue gas entering the boiler contains 1 to 15% carbon monoxide.
- A method as claimed in claim 4, wherein the flue gas entering the boiler contains 8 to 10% carbon dioxide.
- A method as claimed in any one of the preceding claims, wherein the temperature of the burning carbon monoxide is from 800 to 1500°C.
- A method as claimed in any one of the preceding claims, wherein said fluid catalytic cracking regenerator is operating under partial combustion.
- A method according to any one of the preceding claims, additionally comprising introducing a nitrogen-enriched gas stream into the boiler.
- A method as claimed in claim 8, wherein said nitrogen-enriched gas comprises at least 80% by volume of nitrogen.
- A method as claimed in claim 8 or 9, wherein said nitrogen-enriched gas is introduced into said boiler separately from said oxygen-enriched gas.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US70297500A | 2000-10-31 | 2000-10-31 | |
| US702975 | 2000-10-31 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP1201729A2 true EP1201729A2 (en) | 2002-05-02 |
| EP1201729A3 EP1201729A3 (en) | 2002-11-20 |
Family
ID=24823414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP01309166A Withdrawn EP1201729A3 (en) | 2000-10-31 | 2001-10-30 | Fluid catalytic cracking regenerator with reduced NOx emissions |
Country Status (1)
| Country | Link |
|---|---|
| EP (1) | EP1201729A3 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8415264B2 (en) | 2010-04-30 | 2013-04-09 | Uop Llc | Process for regenerating catalyst in a fluid catalytic cracking unit |
| WO2016200566A1 (en) | 2015-06-09 | 2016-12-15 | Exxonmobil Research And Engineering Company | Fluid catalytic cracking unit with low emissions |
| CN113757645A (en) * | 2021-08-17 | 2021-12-07 | 西安交通大学 | Clean air separation gas combustion reactor system and operation method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2853455A (en) * | 1952-09-09 | 1958-09-23 | Sinclair Refining Co | Method of temperature control in fluid catalyst regenerator units |
| US4755282A (en) * | 1987-07-22 | 1988-07-05 | Shell Oil Company | Process for the reduction of NH3 in regeneration zone off gas by select recycle of certain-sized NH3 decomposition catalysts |
| US5021144A (en) * | 1989-02-28 | 1991-06-04 | Shell Oil Company | Process for the reduction of NOX in an FCC regeneration system by select control of CO oxidation promoter in the regeneration zone |
| US5268089A (en) * | 1992-06-24 | 1993-12-07 | Mobil Oil Corporation | FCC of nitrogen containing hydrocarbons and catalyst regeneration |
-
2001
- 2001-10-30 EP EP01309166A patent/EP1201729A3/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8415264B2 (en) | 2010-04-30 | 2013-04-09 | Uop Llc | Process for regenerating catalyst in a fluid catalytic cracking unit |
| WO2016200566A1 (en) | 2015-06-09 | 2016-12-15 | Exxonmobil Research And Engineering Company | Fluid catalytic cracking unit with low emissions |
| US9890334B2 (en) | 2015-06-09 | 2018-02-13 | Exxonmobil Research And Engineering Company | Fluid catalytic cracking unit with low emissions |
| CN113757645A (en) * | 2021-08-17 | 2021-12-07 | 西安交通大学 | Clean air separation gas combustion reactor system and operation method |
Also Published As
| Publication number | Publication date |
|---|---|
| EP1201729A3 (en) | 2002-11-20 |
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