Hydrocarbon Processing - December 2020 - 29

Plant Design, Engineering and Construction
28

TABLE 5. Properties of gasoline and diesel products

pi

Before revamp
After revamp

24

Gasoline
Before
revamp

Item
Elevation/m

20

After
revamp

Before
revamp

After
revamp

Distillation, °C

16

12

ps
po
170

IBP

33.5

31

179

187.5

10%

52.5

49

204.5

207.5

50%

95.5

93.5

273

260.5

90%

168.5

165.5

353.5

354.5

FBP

8
4
160

Diesel

180

190

200

210
p/kPa

220

230

240

250

260

FIG. 5. Pressure profiles of the regenerated standpipe.

the high reaction temperature and the increased catalyst-to-oil
ratio. The increased propylene yield can provide more feedstock for the downstream propylene polymerization unit.

179

191.5

370

372.5

Density, kg/m3

719.5

722.5

881.7

918

Saturates content, %

30.5

40.1

Aromatic content, %

11.5

16.6

Olefin content, %

55.6

43.3

RON

91.8

92.5
36.3

29.2

CN

TABLE 6. Composition of LPG properties
Composition

Operation stability of the revamped FCCU. After revamp,

the VSS and cyclone separators still maintained higher separation efficiencies at a higher processing capacity. This is indicated
by the low solids content in slurry of 1 g/l, slightly higher than
before revamp. The particulate concentrations in the inlets of
the third-stage cyclone and the flue gas turbine could meet the
requirements for long-cycle operation. The increased system
pressure reduced the steam consumption by the steam turbine
and the power consumption for the main air blower.
The fluidization performance of the revamped FCCU was
improved with the redesigned regeneration standpipe. After revamp with the new operation condition, the reaction temperature fluctuation dropped from ±0.5°C to ±1°C, which was the
best level of operating stability in the operating history of the
unit. FIG. 5 compares the pressure distributions in the regenerated catalyst standpipe before and after revamp. Note that pi is
the inlet pressure of the regenerated catalyst standpipe, pS is the
pressure before the slide valve and po is the pressure after the
slide valve. After revamp, the apparent density in the standpipe
was approximately 410 kg/m3. The measured axial pressure distribution was consistent with the designed values. The pressure
before the slide valve increased significantly, from 175 kPa to
250 kPa, as shown in FIG. 5. The pressure drop across the slide
valve increased to 42 kPa, seven times that of the previous value.
The FCCU ran smoothly after revamp. The whole automation level of this unit was also improved considerably after
revamp, which significantly improved the unit's safe operation
performance. Due to the combination of new technologies used
in this revamp, the revamped FCCU has achieved high gasoline
yield and high conversion. As the main air blower and gas compressor were not changed, the investment cost was significantly
reduced and a shortened construction period was realized.
ACKNOWLEDGMENTS
The authors would like to express their gratitude to the Research Foundation of
Karamy campus of China University of Petroleum (Beijing) for their support (Grant
no. RCYJ2016B-02-001).

Before revamp

After revamp

Propane,%

12.58

9.97

Propylene,%

30.57

47.02

n-Butane,%

8.42

4.06

Iso-butane,%

24.09

21.02

n-butene,%

3.76

2.79

Iso-butene,%

10.84

7.49

Trans-butene ,%

4.79

3.45

Cis-butene,%

4.84

3.51

Iso-pentane,%

0.11

0.1

LITERATURE CITED
Complete Literature Cited available online at www.HydrocarbonProcessing.com.
PENG WEI is a Process Engineer for the catalytic cracking unit
of the petrochemical branch of Petrochina. He has worked on
the FCCU for 11 yr and is committed to plant production,
management and technical revamp. Dr. Wei earned his PhD
in chemical engineering from the China University of Petroleum,
where his research included oil and gas processing and
fluidization technology, among other areas.
LIU YANSHENG is a Professor of chemical engineering
at China University (Beijing) and is the Principal of chemical
industry, where he is mainly engaged in distillation processes,
equipment development and application of basic research.
His research interests include transmission and separation
processes, distillation processes, equipment development
and fault diagnosis. He has worked in the chemical engineering
field for more than 30 yr and has been responsible for the technical revamp
of several FCC devices, with extensive experience in device debottlenecking
in the process industries.
QI HONQWEI is a Senior Engineer and the Director of the
science and technology department in the petrochemical
branch of Petrochina. With more than 30 yr of experience,
he is mainly responsible for the fuel oil system technology
management ofthe company. He has been responsible for the
technical revamp of many units, such as the catalytic cracking
unit, delayed coking unit and distillation units. He has
extensive experience in best management practices in the process industries.
Hydrocarbon Processing | DECEMBER 2020

29


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Hydrocarbon Processing - December 2020

Table of Contents for the Digital Edition of Hydrocarbon Processing - December 2020

Contents
Hydrocarbon Processing - December 2020 - Intro
Hydrocarbon Processing - December 2020 - Cover1
Hydrocarbon Processing - December 2020 - Cover2
Hydrocarbon Processing - December 2020 - Contents
Hydrocarbon Processing - December 2020 - 4
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Hydrocarbon Processing - December 2020 - 80A
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Hydrocarbon Processing - December 2020 - Cover3
Hydrocarbon Processing - December 2020 - Cover4
Hydrocarbon Processing - December 2020 - GP-1
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