+ All Categories
Home > Documents > SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a...

SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a...

Date post: 09-Jul-2020
Category:
Upload: others
View: 0 times
Download: 0 times
Share this document with a friend
322
Transcript
Page 1: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

SPRING 2019

CL 4003 PETROCHEMICALS AND REFINERY ENGINEERING

Lecture 29/30

Department of Chemical Engineering

Birla Institute of Technology Mesra, Ranchi1

Page 2: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

AROMATICS PRODUCTION

PROCESSES

2

Page 3: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

✓ An aromatics complex is a combination of process units that

can be used to convert petroleum naphtha and pyrolysis

gasoline (pygas) into the basic petrochemical intermediates:

benzene, toluene, and xylenes (BTX).

3

Primary Fractionation

Page 4: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

✓ Benzene is a versatile petrochemical building block used in the

production of more than 250 different products (2001).

4

Benzene

Page 5: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

✓ The xylenes product, also known as mixed xylenes, contains

four different C8 aromatic isomers: para-xylene, ortho-xylene,

meta-xylene, and ethylbenzene. Small amounts of mixed

xylenes are used for solvent applications, but most xylenes are

processed further within the complex to produce one or more of

the individual isomers.

5

Xylenes

Page 6: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

✓ A small amount of toluene is recovered for use in solvent

applications and derivatives, but most toluene is used to

produce benzene and xylenes.

✓ Toluene is becoming increasingly important for the production

of xylenes through toluene disproportionation and

transalkylation with C9 aromatics.

6

Toluene

Page 7: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

7

CONFIGURATIONS

Aromatics complexes can have many different configurations. The

simplest complex produces only benzene, toluene, and mixed

xylenes and consists of the following major process units:

● Naphtha hydrotreating for the removal of sulfur and nitrogen

contaminants,

● Catalytic reforming for the production of aromatics from

naphtha,

● Aromatics extraction for the extraction of BTX.

Page 8: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

8

Simple aromatics complex

Page 9: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

9

Integrated UOP aromatics complex

✓ Most new aromatics complexes are designed to maximize the

yield of benzene and para-xylene and sometimes ortho-

xylene. The configuration of a modern, integrated UOP

aromatics complex is shown in Figure. This complex has been

configured for maximum yield of benzene and para-xylene and

includes the following UOP process technologies:

Page 10: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

10

Integrated UOP aromatics complex

● CCR Platforming for the production of aromatics from naphtha

at high severity,

● Sulfolane, on extractive distillation for the recovery of benzene

and toluene,

● Parex for the recovery of para-xylene by continuous adsorptive

separation

● Isomar for the isomerization of xylenes and the conversion of

ethylbenzene

● Tatoray for the conversion of toluene and heavy aromatics to

xylenes and benzene

Page 11: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

11

Integrated UOP aromatics complex

Page 12: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

12

DESCRIPTION OF THE PROCESS FLOW

✓ The naphtha is first hydrotreated to remove sulfur and nitrogen

compounds and then sent to a CCR Platforming unit, where

paraffins and naphthenes are converted to aromatics. The CCR

Platforming unit is designed to run at high severity to

maximize the production of aromatics. The reformate

product from the CCR Platforming unit is sent to a debutanizer

column within the Platforming unit to strip off the light ends.

Page 13: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

13

DESCRIPTION OF THE PROCESS FLOW

✓ The reformate from the CCR Platforming unit is sent to a

reformate splitter column. The C7- fraction from the

overhead is sent to the Sulfolane unit for extraction of

benzene and toluene. The C8+ fraction from the bottom of the

reformate splitter is sent to the xylene recovery section of the

complex.

Page 14: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

14

DESCRIPTION OF THE PROCESS FLOW

✓ The Sulfolane unit extracts the aromatics from the reformate

splitter overhead and rejects a paraffinic raffinate stream. High-

purity benzene and toluene products are recovered in the

benzene-toluene (BT) fractionation section of the complex.

✓ The C8+ material from the bottom of the toluene column is sent

to the xylene recovery section of the complex.

✓ The raffinate from the Sulfolane unit may be further refined into

paraffinic solvents, blended into gasoline, used as feedstock for

an ethylene plant, or converted to additional benzene by an RZ-

100 Platforming unit.

Page 15: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

15

DESCRIPTION OF THE PROCESS FLOW

✓ Toluene is usually blended with C9 and C10 aromatics (A9+) from

the overhead of the A9 column and charged to a Tatoray unit for

the production of additional xylenes and benzene.

✓ The effluent from the Tatoray unit is sent to a stripper column

within the Tatoray unit to remove light ends. After that, it is

sent to the BT fractionation section, where the benzene product

is recovered and the xylenes are fractionated out and sent to the

xylene recovery section.

Page 16: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

16

DESCRIPTION OF THE PROCESS FLOW

✓ The overhead material from the Tatoray stripper column is

separated into gas and liquid products. The overhead gas is

exported to the fuel gas system, and the overhead liquid is

normally recycled to the CCR Platforming debutanizer for

recovery of residual benzene.

Page 17: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

17

DESCRIPTION OF THE PROCESS FLOW

✓ The C8+ fraction from the bottom of the reformate splitter is

charged to a xylene splitter column. The overhead from the

xylene splitter is charged directly to the Parex unit.

✓ The xylene splitter bottoms are then sent to an o-X column

where high-purity ortho-xylene product is recovered overhead.

The bottoms from the o-X column are then sent to the A9

column.

Page 18: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

18

DESCRIPTION OF THE PROCESS FLOW

✓ The xylene splitter overhead is sent to the Parex unit, where

99.9 wt % pure paraxylene is recovered by adsorptive

separation.

✓ The raffinate (<1wt% para-xylene) is sent to the Isomar unit,

where additional para-xylene is produced by reestablishing an

equilibrium distribution of xylene isomers.

Page 19: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

19

DESCRIPTION OF THE PROCESS FLOW

✓ Any ethylbenzene in the Parex raffinate is either converted to

additional xylenes or dealkylated to benzene, depending on the

type of Isomar catalyst used.

✓ The effluent from the Isomar unit is sent to a deheptanizer

column. The bottoms from the deheptanizer are recycled back to

the xylene splitter.

✓ In this way, all the C8 aromatics are continually recycled within

the xylene recovery section of the complex until they exit the

aromatics complex as para-xylene, ortho-xylene, or benzene.

Page 20: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

20

DESCRIPTION OF THE PROCESS FLOW

✓ The overhead from the deheptanizer is split into gas and liquid

products.

✓ The overhead gas is exported to the fuel gas system, and the

overhead liquid is normally recycled to the CCR Platforming

debutanizer for recovery of residual benzene.

Page 21: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

21

FEEDSTOCK CONSIDERATIONS

Any of the following streams may be used as feedstock to an

aromatics complex:

● Straight-run naphtha

● Hydrocracked naphtha

● Mixed xylenes

● Pyrolysis gasoline (pygas)

● Coke-oven light oil

● Condensate

● Liquid petroleum gas (LPG)

Page 22: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

22

FEEDSTOCK CONSIDERATIONS

✓ Petroleum naphtha is by far the most popular feedstock for

aromatics production. Reformed naphtha, or reformate,

accounts for 70 percent of total world BTX supply.

✓ The pygas by-product from ethylene plants is the next-largest

source at 23 percent.

✓ Coal liquids from coke ovens account for the remaining 7

percent.

✓ Pygas and coal liquids are important sources of benzene that

may be used only for benzene production or may be combined

with reformate and fed to an integrated aromatics complex.

Page 23: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

23

FEEDSTOCK CONSIDERATIONS

✓ Condensate is a large source of potential feedstock for

aromatics production. Although most condensate is currently

used as cracker feedstock to produce ethylene, condensate will

likely play an increasingly important role in aromatics

production in the future.

✓ Many regions of the world have a surplus of low-priced LPG that

could be transformed into aromatics by using the new UOP-BP

Cyclar process. This Cyclar unit is integrated with a

downstream aromatics complex to produce para-xylene, ortho-

xylene, and benzene.

Page 24: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

24

Overall Material Balance

✓ The feedstock is a common straight-run naphtha derived from

Arabian Light crude.

Page 25: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L29.pdfPROCESSES 2 An aromatics complex is a combination of process units that ... into the basic petrochemical intermediates: benzene,

25


Recommended