Emissions in Remission - Albemarle Corporation

Increasing middle distillates yields in
FCC with MFCC catalysts
Worldwide demand for diesel continues to grow, especially in Western Europe, Asia and Latin America. A
number of factors are driving this increase: the superior economy and efficiency of diesel engines; recent
advances in combustion systems such as the introduction of “Common-Rail” technology; and improvements in
emissions devices including filters for the removal of micro-particulates and NOx reduction systems.
In some regions, the growing use of light vehicles powered by
Otto engines has increased demand for alternative fuels such
as natural gas, LPG and ethanol, contributing to a steady
decline in demand for gasoline in those areas.
These developments have affected the operation of FCC units,
leading an increasing number of refiners to look for routes for
maximizing middle distillates, with a simultaneous reduction
in the yield of cracked naphtha.
Catalyst architecture for middle distillates
maximization
To meet the needs of this growing niche market, FCC S.A. has
developed the (Mild Fluid Catalytic Cracking) MFCC series,
adapted to this new profile of liquid fuels demand. MFCC
increases the volume and quality of middle distillate (Light
Cycle Oil, or LCO) produced while simultaneously reducing
the bottoms yield.
In the development of the MFCC family, special attention was
given to the reaction network of generation and subsequent
conversion (overcracking) of the molecules in the middle
distillates boiling range. The aliphatic compounds (olefins and
paraffins) formed in this cut are easily converted to lighter
products in the naphtha range. Therefore, operation at mild
reaction temperatures is important in order to maintain the
target cutting range. The formation of aromatics is also
reduced through the attenuation of hydrogen transfer
reactions.
Commercial FCC performance with MFCC
catalysts
A first industrial trial of this product family took place in a
UOP HTR FCC unit operated by PETROBRAS/ Brazil, utilizing
MFCC-1 catalyst.
Figures 1 and 2 compare the performance of MFCC-1 with
RUBY 745 catalyst in operations with high reaction
temperatures of approximately 1002°F (540°C). The MFCC-1
achieved increases of the Cetane Index of light cuts (around 6-
7 points) and heavy cuts (3-4 points) of LCO. When the
severity of the reaction was reduced through a lower reaction
8 Courier ■ Issue 66
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36
34
32
30
28
26
24
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Figure 1: Cetane Index of light LCO (industrial test)
temperature (RXT), additional gains in distillate volume and
the Cetane Index occurred, achieving a Cetane Index of 36 for
light LCO and 32 for the heavy LCO.
Table 1 summarizes the data from this industrial test. The final
column contains the best condition obtained during the test
of the MFCC-1 catalyst. Significant gains in LCO yield can be
noted, around 40% compared to RUBY 745 at high reaction
temperature, with an important improvement of the LCO
properties.
34
32
30
28
26
24
22
20
RUBY-745 MFCC-1
Cetane Index ASTM D-4737
Heavy LCO
RUBY-745 MFCC-1
Cetane Index ASTM
Light LCO
Reduction of severity
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Dates
Reduction of severity
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Dates
Figure 2: Cetane Index of heavy LCO (industrial test)