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Page 1: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

SPRING 2019

CL 4003 PETROCHEMICALS AND REFINERY ENGINEERING

Lecture 33

Department of Chemical Engineering

Birla Institute of Technology Mesra, Ranchi1

Page 2: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

cumene

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Page 3: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ Cumene is used to manufacture other chemicals such as

phenol, acetone, acetophenone, and methyl styrene.

✓ It is used as a thinner in paints, lacquers, and enamels.

✓ It is a component of high octane motor fuels.

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INTRODUCTION

Page 4: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The production of cumene (isopropyl benzene) involves the

reaction of benzene with propylene in a high-temperature,

high-pressure gas-phase reactor.

C6H6 + C3H6 → C9H12

✓ There is also a sequential reaction of cumene and propylene to

form p-diisopropylbenzene (PDIB).

C9H12 + C3H6 → C12H18

✓ The benzene is kept in excess to limit the amount of DIPB

product.

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Process Description

Page 5: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

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Process Description

Page 6: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ Propylene obtained from refinery processes as a mixture of

propylene and propane.

✓ The mixture along with benzene is compressed to 25 atms.

✓ Eventually the mixture enters a heat integrated exchanger to

pre-heat the feed mixture.

✓ The feed mixture enters a packed bed reactor.

✓ Cold propane from the distillation column in the process is

added after every reactor with the product stream so that the

temperature of the stream is controlled.

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Process Description

Page 7: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ Here, propylene is the limiting reactant and therefore,

presumably all propylene undergoes conversion.

✓ Here, propane does not react but is a diluents or inert in the

system. In that way it controls the reaction temperature.

✓ The reactor units are maintained at about 250 °C.

✓ The product vapors are cooled using the heat integrated

exchanger.

✓ The vapors then pass to a de-propanizer which separates

propane from the product mixture.

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Process Description

Page 8: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The bottom product consisting of benzene, cumene and

polyalkyl benzenes enters another distillation column which

separates benzene from the mixture of cumene and polyalkyl

benzene. The benzene stream is recycled to enter the

compressor.

✓ The bottom product from the benzene column is sent to a

cumene column which produces cumene as top product and

poly alkyl benzene as bottom product.

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Process Description

Page 9: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

Phenol

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Page 10: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The largest end-use for phenol is in the manufacture of

bisphenol A (BPA). Although it is under regulatory pressure for

health and safety reasons, BPA is the key building block for

making polycarbonate and epoxy resins.

✓ The next largest use for phenol is in the production of phenol-

formaldehyde (PF) resins. PF resins are used primarily in wood

adhesives, for example, for bonding the layers of plies in exterior

plywood.

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INTRODUCTION

Page 11: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ Around 98% of cumene is used to produce phenol and its co-

product acetone.

✓ The largest phenol derivative is bisphenol-A (BPA) which

supplies the growing polycarbonate (PC) sector.

✓ PC resins are consumed in automotive applications in place of

traditional materials such as glass and metals. Glazing and

sheet uses, such as architectural, security and glazing outlets,

are also important PC applications. The third largest use for PC

is optical media such as compact discs (CDs) and digital

versatile discs (DVDs).11

INTRODUCTION

Page 12: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ BPA’s other main derivative is epoxy resins which are used in

high performance coatings, electrical-electronic laminates,

adhesives, flooring and paving applications, and composites.

✓ Phenol’s other derivatives include phenolic resins which are

largely used as durable binders and adhesives in structural

wood panels and as binders in mineral wool insulation.

✓ Another phenol derivative is caprolactam which is used mainly

to make nylon 6. It is mainly the engineering resin sector of the

nylon market that is seeing growth.

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INTRODUCTION

Page 13: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The key drivers in the acetone market are methyl methacrylate

(MMA) and BPA. Nearly all MMA is used to make homopolymers

and copolymers with electronic applications such as flat screen

TVs and liquid crystal displays providing growth opportunities.

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INTRODUCTION

Page 14: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ In the Hock process, cumene (1, made by alkylating benzene

with propylene) is oxidized to cumene hydroperoxide (2), which

is then cleaved to a mixture of phenol (3) and acetone (4) by

treating it with H2SO4.

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Hock process

Page 15: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The good news is that for every 10 kg of phenol produced, 6.2

kg of acetone is coproduced. The bad news is that for every 10

kg of phenol produced, 6.2 kg of acetone is coproduced. The

process can be good or bad, depending on the petrochemical

market.

✓ “Two-for-one” processes sound good in concept, but they only

work commercially if the markets for both products are

changing at about the same rate. Otherwise, one product will be

in oversupply, which causes its price to fall and penalizes the

economics of the entire process. 15

Hock process

Page 16: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

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Hock process

Page 17: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ Fresh cumene is mixed with hydrogenated unreacted cumene,

cumene + alpha methyl styrene (recycle streams).

✓ The pre-purification step involves converting unsaturates such

as alpha methyl styrene and others to saturates. This is done by

using nickel catalyst at 100°C and feeding hydrogen to the pre-

purification reactor. The product from this unit then mixes with

the fresh cumene.

✓ The fresh cumene and processed cumene and alpha methyl

styrene are fed to the oxidation reactor. The oxidation reactor

refers to a gas-liquid reaction between air (Oxygen) and cumene.17

Process Description

Page 18: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ An emulsion of cumene is prepared in the oxidation reactor by

adding alkali to it.

✓ pH is maintained in the range of 8.5 – 10.5 to suit good

emulsification conditions.

✓ After reaction, vent gases are condensed and recycled back and

the product is sent to a cleavage unit.

✓ The cleavage unit consists of a stirrer and is fed with fresh and

recycled H2SO4 aqueous solution to enable the hydrolysis of

cumene hydroperoxide.

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Process Description

Page 19: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The product streams from the cleavage unit enter a settler

(phase separator) which upon gravity settling yields two streams

namely the acid rich aqueous stream and the phenol rich

organic stream.

✓ The aqueous stream consists of the sulphuric acid and is sent

back to the cleavage unit as a recycle stream.

✓ The organic stream consists of cumene (unreacted), phenol

(product), acetone (side product), alpha methyl styrene (side

product) and acetophenone (side product).

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Process Description

Page 20: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The organic stream from the gravity settler unit then enters a

scrubber fed with water. In this operation, water extracts the

remaining acids in the organic stream and produces crude

phenol stream. Water leaving the unit consists of acidified wash

water.

✓ The crude phenol then enters a distillation unit that separates

acetone from the other components.

✓ The bottom product from this distillation column enters a

vacuum distillation column that produces cumene as a top

product.20

Process Description

Page 21: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

✓ The bottom product from the distillation column enters another

vacuum distillation unit to produce alpha methyl styrene.

✓ The bottom product of this distillation column enters the final

vacuum distillation unit to produce phenol as top product and

acetophenone as the bottom product.

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Process Description

Page 22: SPRING 2019 - Anand Bhartianandbharti.co.in/pre/L33.pdfIn the Hock process, cumene (1, made by alkylating benzene with propylene) is oxidized to cumene hydroperoxide (2), which is

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