I.FLUID CATALYTIC CRACKING: www.wissenschaftler-avh.in
B.CATALYST/ADDITIVES(Contd.)
Q-52:
Pl .Highlight the role of LOW RARE EARTH CATALYSTS in FCC operation?
A-52:
For decades, rare earth elements have performed vital roles in refinery catal-ysis and their availability, at reasonable prices, has been taken for granted. However, when the global supply became restricted, refiners faced spiral- ling costs and were forced to re-examine how they used rare earth elements.
Uses of rare earth elements
The rare earth elements are lanthanum, cerium, praseodym- ium, neodymium, promethium, samarium, europium, gadolin- ium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Yttrium and sometimes scandium are often grouped as rare earth elements because of their similar chemical properties. These elements have a widerange of industrial applications. They have taken an important role in oil refining catalysts, additives and processes for many years, and also make vital contributions to other applications. Selected end uses for rare earths are shown in Table 1.Global demand for rare earth elements is currently about 134 000 t/y, but worldwide annual production amounts to 124 000 tonnes, the difference being drawn from previously mined stocks.
However, the availability of rare earths can no longer be taken for granted. In 2009, China, the largest producer of rare earth elements,( output 97% of the world’s rare earths measured in terms of oxide content.) cut its export of rare earths from about 50 000 tonnes in 2009 to 30 000 tonnes in 2010. The country also plans to reduce output further by eliminating prohibited rare earth mining operations. This is likely to restrict the availability of rare earth elements even more. Greater emphasis by the Chinese authorities on the safety and environmental aspects of mining operations are likely to increase operating costs. The much-reduced availability of rare earths means that their price has soared. The price for lanthanum, for example, surged from some $6000/t in May 2010 to about $140 000/t in May 2011.
Selected uses of rare earth elements
Light rare earth element Major end use Heavy rare earth element Major end use Lanthanum Hybrid engines, metal alloys, refining catalysts Terbium Phosphors, permanent magnets Cerium Automotive catalysts, refining catalysts, metal alloys Dysprosium Permanent magnets, hybrid engines Praseodymium Magnets Erbium Phosphors
Neodymium Automotive catalysts, hard drives in laptops, headphones, hybrid engines Holmium Glass colouring, lasers Samarium Magnets Thulium Medical X-ray units Europium Red colouration for television and computer screens Ytterbium Lasers, steel alloys Gadolinium Magnets
Table 1 Adapted from: DOI, US Geological Survey, Circular 930-N
Laboratory comparison of two catalysts with the same formulation but with and without rare earth exchange
Catalyst no rare earth rare earth exchanged
RE2O3, wt% 0.0 1.0
Conversion at C/O = 4 wt/wt, wt% Base +6.9
Yield structure, wt%
Dry gas Base +0.90
Propane Base +0.19
Propylene Base +0.44
n-butane Base +0.15
i-butane Base +0.66
Butylenes Base +0.28
Gasoline Base +4.8
Light cycle oil Base -1.1
Bottoms Base -5.8
Coke Base +0.9
Selectivities, wt/wt
C3-olefinicity Base -0.02
C4-olefinicity Base -0.08
Gasoline/conversion Base +0.01
Coke/second order conversion Base -0.40
Table 2
This comparison at a constant catalyst-to-oil ratio (C/O)shows the typical changes through applying rare earth exchange to zeolites:• The activity is substantially increased, which results in much higher liquefied petroleum gas (LPG) and particularly, gasoline yield,mainly at the cost of bottoms
• The olefinicity of the LPG fraction is decreased • Owing to the lower olefinicity, gasoline olefinicity and octanes will also increase.• Coke and delta coke are also increased.No other elements have yet been found to increase zeolite activity and stability as efficiently as rare earth elementsThere are limited sources of rare earth elements outside China but the quantities currently produced are too low to have any significant impact on short-term supply. Initiatives are being taken in, for example,Australia, Brazil, Canada, South Africa, Greenland and the US, to find and develop new sources of rare earths or to reopen mines previously considered uneconomic. But, as demand is projected to increase from 134 000 t/y to 180 000 t/y in 2012, it is unlikely that any new rare earth production will close the widening gap in the short term,as greenfield mining projects could take 10 years to reach production.
Rare earth elements in FCC catalysts
Rare earths have found applications in oil refining for FCC catalysts and additives, which use lanthanum and cerium.Lanthanum and cerium are used in FCC catalysts because they substantially increase the activity and stability of the zeolite, which is the most active component in the catalysts.Lanthanum is most commonly used to increase the activity and stability of zeolites.The effects of lanthanum on the performance of a zeolite-containing FCC catalyst are shown in Table 2. This data was obtained from laboratory work in which two catalysts were compared in the short-contact- time riser test (SCT-RT)after a two-step cyclic metal deactivation with 5000 ppm of nickel (Ni), 5000 ppm of vanadium (V) and a residue feed stock. The catalysts have the same composition, but the first one has not been exchanged with rare earth and the second one contains 1 wt% RE2O3.
CONCLUSIONS
Rare earth elements have been of great importance to oil refiners for processing marginal feedstocks in the FCC unit, which is still the preferred unit for converting marginal feed-stocks into LPG and transportation fuels. However, soaring rare earth prices have created turmoil for the refining industry.
B.CATALYST/ADDITIVES(Contd.)
Q-52:
Pl .Highlight the role of LOW RARE EARTH CATALYSTS in FCC operation?
A-52:
For decades, rare earth elements have performed vital roles in refinery catal-ysis and their availability, at reasonable prices, has been taken for granted. However, when the global supply became restricted, refiners faced spiral- ling costs and were forced to re-examine how they used rare earth elements.
Uses of rare earth elements
The rare earth elements are lanthanum, cerium, praseodym- ium, neodymium, promethium, samarium, europium, gadolin- ium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. Yttrium and sometimes scandium are often grouped as rare earth elements because of their similar chemical properties. These elements have a widerange of industrial applications. They have taken an important role in oil refining catalysts, additives and processes for many years, and also make vital contributions to other applications. Selected end uses for rare earths are shown in Table 1.Global demand for rare earth elements is currently about 134 000 t/y, but worldwide annual production amounts to 124 000 tonnes, the difference being drawn from previously mined stocks.
However, the availability of rare earths can no longer be taken for granted. In 2009, China, the largest producer of rare earth elements,( output 97% of the world’s rare earths measured in terms of oxide content.) cut its export of rare earths from about 50 000 tonnes in 2009 to 30 000 tonnes in 2010. The country also plans to reduce output further by eliminating prohibited rare earth mining operations. This is likely to restrict the availability of rare earth elements even more. Greater emphasis by the Chinese authorities on the safety and environmental aspects of mining operations are likely to increase operating costs. The much-reduced availability of rare earths means that their price has soared. The price for lanthanum, for example, surged from some $6000/t in May 2010 to about $140 000/t in May 2011.
Selected uses of rare earth elements
Light rare earth element Major end use Heavy rare earth element Major end use Lanthanum Hybrid engines, metal alloys, refining catalysts Terbium Phosphors, permanent magnets Cerium Automotive catalysts, refining catalysts, metal alloys Dysprosium Permanent magnets, hybrid engines Praseodymium Magnets Erbium Phosphors
Neodymium Automotive catalysts, hard drives in laptops, headphones, hybrid engines Holmium Glass colouring, lasers Samarium Magnets Thulium Medical X-ray units Europium Red colouration for television and computer screens Ytterbium Lasers, steel alloys Gadolinium Magnets
Table 1 Adapted from: DOI, US Geological Survey, Circular 930-N
Laboratory comparison of two catalysts with the same formulation but with and without rare earth exchange
Catalyst no rare earth rare earth exchanged
RE2O3, wt% 0.0 1.0
Conversion at C/O = 4 wt/wt, wt% Base +6.9
Yield structure, wt%
Dry gas Base +0.90
Propane Base +0.19
Propylene Base +0.44
n-butane Base +0.15
i-butane Base +0.66
Butylenes Base +0.28
Gasoline Base +4.8
Light cycle oil Base -1.1
Bottoms Base -5.8
Coke Base +0.9
Selectivities, wt/wt
C3-olefinicity Base -0.02
C4-olefinicity Base -0.08
Gasoline/conversion Base +0.01
Coke/second order conversion Base -0.40
Table 2
This comparison at a constant catalyst-to-oil ratio (C/O)shows the typical changes through applying rare earth exchange to zeolites:• The activity is substantially increased, which results in much higher liquefied petroleum gas (LPG) and particularly, gasoline yield,mainly at the cost of bottoms
• The olefinicity of the LPG fraction is decreased • Owing to the lower olefinicity, gasoline olefinicity and octanes will also increase.• Coke and delta coke are also increased.No other elements have yet been found to increase zeolite activity and stability as efficiently as rare earth elementsThere are limited sources of rare earth elements outside China but the quantities currently produced are too low to have any significant impact on short-term supply. Initiatives are being taken in, for example,Australia, Brazil, Canada, South Africa, Greenland and the US, to find and develop new sources of rare earths or to reopen mines previously considered uneconomic. But, as demand is projected to increase from 134 000 t/y to 180 000 t/y in 2012, it is unlikely that any new rare earth production will close the widening gap in the short term,as greenfield mining projects could take 10 years to reach production.
Rare earth elements in FCC catalysts
Rare earths have found applications in oil refining for FCC catalysts and additives, which use lanthanum and cerium.Lanthanum and cerium are used in FCC catalysts because they substantially increase the activity and stability of the zeolite, which is the most active component in the catalysts.Lanthanum is most commonly used to increase the activity and stability of zeolites.The effects of lanthanum on the performance of a zeolite-containing FCC catalyst are shown in Table 2. This data was obtained from laboratory work in which two catalysts were compared in the short-contact- time riser test (SCT-RT)after a two-step cyclic metal deactivation with 5000 ppm of nickel (Ni), 5000 ppm of vanadium (V) and a residue feed stock. The catalysts have the same composition, but the first one has not been exchanged with rare earth and the second one contains 1 wt% RE2O3.
CONCLUSIONS
Rare earth elements have been of great importance to oil refiners for processing marginal feedstocks in the FCC unit, which is still the preferred unit for converting marginal feed-stocks into LPG and transportation fuels. However, soaring rare earth prices have created turmoil for the refining industry.
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