Hydrocarbon Processing - December 2022 - 32

Catalysts
as SCY) is much stronger than the commercial small-sized Y
zeolite while similar to the regular NaY zeolite. It is well-known
that the synthesized zeolite materials entail a strong resistance to
the steam during the application in a real refinery. Normally, the
structure of regular zeolite can be dramatically destructed by the
steam at high temperature. To enhance the hydrothermal stability
of the authors' company's SCY zeolite materials, a gas-phase
hyperstabilization method was conducted. As shown in FIG. 3D,
although the relative crystallinity of the SCY zeolite is almost
identical to the commercial NaY zeolite, the crystallinity retention
of SCY is significantly higher than its counterpart.
Strategy for the new matrix. In addition to zeolites, matrix
should also be considered as another important component in
terms of alteration of catalyst activity. The poor accessibility of
heavy oil molecules to the active centers of zeolites significantly
impedes their diffusion in the zeolite channels. Therefore, the
pre-activation of heavy oil molecules on a specific matrix is imperative,
requiring the development of a new matrix with proper
size. One of the underlying challenges is to balance the matrix's
pre-activated ability and the selectivity of coke formation. Therefore,
to curb the formation of coke, the Lewis acid in the matrix
must be further reduced and weakened. Compared to a regular
matrix, the newly developed matrix, marked as LOM, shows a
unique fabric-like morphology with 8-nm mesopores, which
is higher than the pore diameter of the regular matrix (FIG. 4).
The larger pore diameter is not only beneficial to the diffusion
of large molecules, but decreases the possibility of bimolecular
reaction and (consequently) the yield of coke. Further experiments
confirm that the amount of whole Lewis acid as well as
the amount of strong Lewis acid in the novel matrix decreases
dramatically, contributing to less coke formation (TABLE 1).
Industrial application of the new catalysta
aforementioned experimental studies, the new catalysta
. Based on the
, combined
with SCY zeolite and LOM matrix, was successfully
produced. It should be highlighted that this catalyst was used
in an industrial FCCU from September 15, 2019, to improve
the conversion and product distribution of heavy oil and boost
the economic performance. The FCCU mentioned is owned by
TABLE 1. Acidity of Lewis acid of diff erent matrix
Acidity of Lewis acid/ (μmol/g)
FIG. 2. Simplified explanation of difference between different-sized
zeolite materials.
Al2
O3
LOM
Total Lewis acid
31.2
17.8
Strong Lewis acid
18.9
3.3
TABLE 2. Primary properties of raw materials used in blank
calibration and summary calibration
Density, kg/m3
Carbon residue, %
Basic nitrogen, μg/g
Saturated hydrocarbons, %
Aromatic hydrocarbons, %
Gums, %
Asphalts, %
FIG. 3. TEM image of (A) commercial NaY zeolite, (B) SCY zeolite, (C)
crystalline structure collapse temperature of different Y zeolites and
(D) relative crystallinity and crystallinity retention of SCY and NaY.
Blank calibration Summary calibration
921.8
2
785
57.3
28
14.3
0.4
926.5
2.96
737
58.8
27
13.7
0.5
TABLE 3. Basic operation conditions in blank calibration and
summary calibration
Inlet rate, t × h-1
Residue ratio, %
Pre-heated temperature, °C
Reaction temperature, °C
Reaction pressure, kPa
Regeneration pressure, kPa
Main fl ow, m3 × min-1
Dense bed temperature
in regenerator, °C
FIG. 4. Pore size distribution curve of (A) commercial Al2
LOM. Insets are the TEM images of commercial Al2
32 DECEMBER 2022 | HydrocarbonProcessing.com
O3 and (B)
O3 and LOM.
Lean bed temperature
in regenerator, °C
Blank calibration Summary calibration
112.7
64.5
200
515
205
232
1,935
715
678
115.3
66.9
201
515
213
236
1,842
715
681
http://www.HydrocarbonProcessing.com
Hydrocarbon Processing - December 2022

Table of Contents for the Digital Edition of Hydrocarbon Processing - December 2022
