Hydrocarbon Processing - November 2021 - 59

Sustainability
3. Integration of amorphous nickel
with a magnetically stabilized
bed. The large-radius,
rare-earth atoms
are introduced into
amorphous nickel to
improve the catalyst
thermal stability, and the
surface area is improved
by the method of " addingleaching
aluminum. " 13
Magnetic retainer
internals are developed
to ensure the uniformity of the
magnetic field in the magnetically
stabilized bed.14
As a result,
unstable Raney nickel catalyst is
not used, and the operation cost
of the CPL production unit is
reduced significantly.
The first industrial plant based on the
authors' company's CPL green production
technology with a capacity of 70 kt·a-1
was built in 2003. FIG. 2 shows a 400-kt·a-1
CPL production plant with green production
technology. Compared with traditional
CPL production technology, the
green CPL production technology reduces
the exhaust gas by 95%, no low-valued
ammonium sulfate is produced, and the
overall investment can drop by 70%. A
CPL production unit with a capacity of
50 kt·a-1
can reduce 2.4 × 108
m3
of waste
gas emissions and 80 kt of low-valued ammonium
sulfate production every year.
The proprietary green CPL production
technology has strongly supported
the technological upgrading of CPL production
in China. In 2020, China's CPL
capacity based on this green production
technology reached 4,000 kt·a-1
rohydrin process and co-oxidation process.
Hypochlorous acid is used as oxidant
quality equipment material. This results
in high equipment costs. Additionally,
Traditional nitridation or oxidation reactions have
poor atom utilization and cause serious pollution
due to the undesirable oxidants that are used.
Green hydrocarbon oxidation and nitridation
technologies with green oxidants are urgently needed.
in the chlorohydrin process, resulting in
serious equipment corrosion and environmental
pollution. When producing 1 t
of propene oxide, the chlorohydrin process
consumes 1.35 t-1.85 t of chlorine
gas, and produces 40 t-80 t of chlorinecontaining
wastewater and more than 2 t
of calcium chloride (CaCl2
). Though the
construction of new plants for producing
propene oxide with the chlorohydrin
process has been strictly controlled since
2011, the chlorohydrin process still accounts
for more than 50% in the production
of propene oxide in China.
To overcome the disadvantages of the
chlorohydrin process, the co-oxidation
process was developed. Though the cooxidation
process solves the equipment
corrosion and environmental pollution
problems, the co-oxidation process with
ethylbenzene or isobutane as a co-reductant
is complicated, and requires harsh
reaction conditions that necessitate highthe
quality of propene must be high, and
the economic benefit is restricted by the
co-products, as 2.2 t-2.5 t of styrene or
2.3 t of tert-butanol is produced when
producing 1 t of propene oxide. The
co-oxidation route with cumene as coreductant
does not produce co-product,
but it does consume significant energy
due to the separation and conversion of
intermediate products. Additionally, it
requires the construction of a large-scale
oxidation unit of cumene.
Technologies for propene oxide production
by direct epoxidation of propene
have been developed in recent years.
Among them, the direct epoxidation
technology with H2
O2 as the oxidant
and TS-1 zeolite as the catalyst (HPPO
process) is the most mature, and it has
been industrialized. Compared with the
chlorohydrin method, the C atom utilization
of the HPPO process is close to
100%, with reductions in equipment in,
giving
China a global market share that exceeds
50% and making it the world's largest
CPL producer-a huge leap from China's
original position of relying almost totally
on CPL importation. The green CPL production
technology also sets a successful
example of green hydrocarbon nitridation.
Green production technology of
propene oxide. As the third-largest propene
derivative, propene oxide is widely
used in unsaturated resins, surfactants
and polyurethanes. In 2020, the actual
output of propene oxide in China was
2.9 × 106
approximately 1.05 × 107
Traditional industrial production processes
of propene oxide include the chlot,
compared to a global output of
t.
FIG. 3. A 100-kt·a-1
propene oxide industrial production unit. Source: Sinopec.
Hydrocarbon Processing | NOVEMBER 2021 59
Hydrocarbon Processing - November 2021

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