Cumene manufacturing procedure

Manufacturing of Cumene

Gharda institute of technology, lavel Page 1

Chapter 1

INTRODUCTION

Cumene is the common name for isopropyl benzene, an organic compound that is an

aromatic hydrocarbon. It is a constituent of crude oil and refined fuels. It is a flammable

colorless liquid that has a boiling point of 152 °C. Nearly all the cumene that is produced as a

pure compound on an industrial scale is converted to cumene hydro-peroxide, which is an

intermediate in the synthesis of other industrially important chemicals such as phenol and

acetone.

Cumene (isopropyl benzene) is produced by reacting propylene and benzene over an

acid catalyst. Cumene may be used to increase the octane in gasoline, but its primary use is as a

feedstock for manufacturing phenol and acetone. The preparation of cumene was first described

in 1841 when Gerhardt and Cahours obtained it by distilling cumic acid with lime. The use of

aluminium chloride to alkylate benzene was reported by Radziewanowski in 1892. Before the

development of the cumene route to phenol and acetone, cumene had been used extensively

during World War II as a fuel additive to improve the performance of aircraft piston engines.

Like phenol and acetone, α-methylstyrene, diisopropylbenzene, or acetophenone, although these

cumene derivative compounds are of considerable commercial importance. Currently, over 80%

of all cumene is produced by using zeolite based processes. Early processes using zeolite based

catalyst system were developed in the late 1980s.[9]



Chapter 2

PROPERTIES

Cumene is colorless liquid soluble in alcohol, carbon tetra chloride, ether and benzene. It

is insoluble in water.

2.1 PHYSICAL PROPERTIES OF CUMENE[8]

PROPERTY VALUE

Molecular weight 120.19

Boiling Point, °C 152.39

Freezing point, °C -96.03

Density, gm/cm3

0°C

20°C

40°C

0.8786

0.8169

0.8450

Thermal conductivity, w/m.k

25°C

0.124

Viscosity, mPa.s (cp)

0°C

20°C

40°C

1.076

0.791

0.612

Surface tension, mN/m

20°C

0.791

Flash point, °C 44

Autoignition temperature, °C 523



Antoine Constants

A

B

C

13.99

3400

207.78

2.2 THERMODYNAMIC PROPERTIES OF CUMENE[8]

PROPERTY VALUE

Relative molar mass 120.2

Critical temperature, °C 351.4

Critical pressure, Kpa 3220

Critical density, g/cm3 0.280

Heat of vapourisation at bp, J/g 312

Heat of vapourisation at 25°C, J/g 367

2.3 CHEMICAL PROPERTIES:[8]

1. Cumene undergoes oxidation t o give cumene hydroperoxide by means of air or

Oxygen

C6H5CH(CH3)2 + O2 C6H5C(CH3)2OOH

Cumene Oxygen Cumene Hydroperoxide

2. By the catalytic action of dilute sulphuric acid, cumene hydroperoxide is split into

Phenol and acetone

C6H5C(CH3)2OOH C6H5OH + CH3COCH3

Cumene Hydroperoxide Phenol Acetone



Chapter 3

USES

Cumene is used[2]

1. As feedback for the production of Phenol and its co-product acetone

2. The cumene oxidation process for phenol synthesis has been growing in popularity

Since the 1960’s and is prominent today. The first step of this process is the formation

of cumene hydroperoxide. The hydroperoxide is then selectively cleaved to Phenol

and acetone.

3. Phenol in its various for maldehyde resins to bond construction materials like plywood

and composition board (40% o f the phenol produced) for the bisphenol. A employed

in making epoxy resins and polycarbonate (30%) and for caprolactum, the starting

material for nylon-6 (20%). Minor amounts are used for alkylphenols and

pharmaceuticals.

4. The largest use for acetone is in solvents although increasing amounts are used to

make bisphenol A and methylacrylate.

5. Methylstyrene is produced in controlled quantities from the cleavage of cumene

Hydroperoxide or it can be made directly by the dehydrogenation o f cumene.

6. Cumene in minor amounts is used as a thinner for paints, enamels and lacquers and to

produce acetophenone, the chemical intermediate dicumylperoxide and diisopropyl

benzene.

7. Cumene is also used as a solvent for fats and raisins.



Chapter 4

MANUFACTURING PROCESSES OF CUMENE.

There are four types of manufacturing process of cumene.

1. Liquid phase alkylation using Phosphoric acid.

2. Liquid phase alkylation using Aluminium chloride.

3. Q-Max process.

4. CD-Cumene process.

4.1 LIQUID PHASE ALKYLATION USING PHOSPHORIC ACID [2]

4.1.1 INTRODUCTION

SPA (Solid phosphoric acid) remains a viable catalyst for cumene syenthesis. In recent

years , producers have been given increasing incentives for better cumene product quality of the

phenol, acetone, and especially alpha-methyl styrene produced from the downstream phenol

units.

4.1.2 CHEMICAL REACTION

Main Reaction

C6H6 + CH3.CH=CH2 C6H5. C3H7 ;

Side Reaction

C6 H6 + nCH3CH=CH2 C6 H6-n.(CH)n

4.1.3 PROCESS DESCRIPTION

Propylene-propane feedstock from refinery off gases from a naphtha steam cracking

plant and recycle benzene is mixed with benzene are charged upflow into fixed bed reactor,

which operates at 3-4 MPa and at 200-260 C and pumped at 25 atms. Into the top of a reactor

packed stage wise with H3PO4 impregnated catalyst. The SPA catalyst provides an essentially

complete conversion of propylene on a one pass basis. The temperature is maintained at

approximately 250 C by adding cold propane at each stage to absorb heat of reaction.

The reactor effluent is depropanized and the propane split into quench or product streams.

The propanized bottoms are separated into benzene, cumene,and polycumenes in the remaining

Jie_Sheng

Highlight



two stills. A typical reactor effluent stream contain 94.8 wt% cumene and 3.1 wt%

diisopropylbenzene (DIPB). The remaining 2.1% is primarily heavy aromatics. This high yield

of cumene is achieved without transalkylation of DIPB is the key advantage of SPA catalyst

process. The cumene product is 99.9 wt% pure. The heave aromatics which have research octane

no (RON) of about 109 can be either used as high octane gasoline blending components or

combined with additional benzene and sent to transalkylation section of the plant where DIPB is

converted to cumene. The overall yield of cumene for this process based on benzene and

propylene is typically 97-98 wt% if transalkylation is included or 94-96 wt% without

transalkylation



4.1.4 PROCESS FLOW DIAGRAM

Figure 4.1.4.a Liquid phase alkylation using phosphoric acid



4.2 LIQUID PHASE ALKYLATION USING AlCl3 [2]

4.2.1 INTRODUCTION

Aluminium chloride is a preferred alkylating agent for the production of cumene.

Basically the design is same to that described for other processes, having pretreatment section if

required, a reactor section and a distillation section. The reaction conditions, including

arrangement for the feeding catalyst and recycle of polyalkylbenzenes for dealkylation are

however quite different.

4.2.2 PROCESS DESCRIPTION-

If feed treatment is required depending on the quality of feedstock, propylene is dried in a

regenerative absorptive drier and fed to de-ethanizer where c2 compounds are distilled. The

bottoms pass to a propylene column where c4’s and heavier are removed in the base stream.

Liquid propylene in the overheads is vaporized and fed to the reactor. Fresh benzene contains too

much water for immediate addition to the reactors, is mixed with recycle benzene and fed to

column. After condensation, benzene and water separate in a decanter. Benzene from the base

contains less than 10ppm water.

The reaction section usually consists of two or more brick lined vessels partitioned into

reaction and settling zones with downstream separators and wash drums. All the reactants and

recycle streams are introduced into the reaction zone. Since agitation is required, propylene

vapours are admitted at the base where catalyst complex, which is insoluble in a hydrocarbon,

tends to settle. The complex is hereby lifted and mixed intimately with the reactants. Aluminium

chloride is added to the top of the reactor and the promoter usually HCl or isopropyl enters with

the reactant. The promoter is essential for stabilizing the catalyst complex, for only a stable

complex will catalyze the reaction. In addition to the gaseous feed to distribute the catalyst

complex, there may be provided a pump to recirculate settled complex to the top of the reaction

zone and a compressor to recycle propane. The distillation section consist of ethylbenzene unit

have been constructed where the catalyst complex is prepared in a separate vessel. Care has to be

taken with the reactor off gases which in addition to benzene and other light hydrocarbons

contains HCl. The benzene is recovered in an absorber containing recycling PAB and the HCl is

scrubbed out of the off- gas in two towers, one containing water and the other containing caustic



soda solution. The residual gas can be compressed and used as fuel. The material heavier than

cumene is not disposed of as fuel, is returned to the reactors for transalkylation after removing

the heaviest polyalkylbenzenes. The later operation is conducted in a small column under high

vacuum.




Fig 4.2.3.a Liqid phase alkylation using Aluminium Chloride



4.3 Q-MAX PROCESS[1,5,6]

4.3.1 INTRODUCTION

The Q- Max process is based on liquid phase process. The Q-Max process produces

nearly equilibrium levels of cumene between 85 to 95 mole% and DIPB between 5 and 15

mole%. The Q-Max process had selected most promising catalyst based on beta zeolite for

cumene production.


A Q-max unit consists of an alkylation reactor, a distillation section, and a transalkylation

reactor. Both reactors are fixed bed. The alkylation reactor is divided into four catalyst beds

contained in a single reactor vessel. Propylene and a mixture of fresh and recycle benzene are

charged to the alkylation reactor, where the propylene reacts to completion to form mainly

cumene. Effluent from the alkylation reactor is sent to the depropanized column, which removes

the propane that entered the unit with the propylene feed, along with any excess water which

may have accompanied the feeds. The Depropanizer column bottoms is sent to the benzene

column where benzene is collected overhead and recycled. Benzene column bottom is sent to the

cumene column where cumene product is recovered overhead. The bottom from the cumene

column, containing mostly diisopropylbenzene is sent to the DIPB column where DIPB is

recovered and recycled to the transalkylation reactor. The bottoms from the DIPB column consist

of a small stream of heavy aromatic by-product which are normally used as high octane gasoline

blending component.

The catalyst in both the alkylation and transalkylation reactors is regenerable. The typical

design cycle length between regenerations is 2years, but the unit can be designed for somewhat

longer cycles if desired. Ultimate catalyst life is at least three cycle. Mild operating conditions

and a corrosion free process environment permit the use of carbon steel construction and

conventional process equipment.




Recycle Benzene

Benzene

Propylene

Cumene

DIPB

Heavies

DIPB

Column

Cumene

Column

Benzene

Column

Transalkylation

Reactor Depropanizer

Alkylation

Reactor

Propane

Figure4.3.3.a : Q-Max process



4.4 CD CUMENE PROCESS[1]

4.4.1 INTRODUCTION

The CD- Cumene process produces ultra high purity cumene using a proprietary zeolite

catalyst that is non corrosive and environmentally friendly.


Cumene is formed by the catalytic alkylation of benzene with propylene. CD-cumene

process uses a proprietary zeolite catalyst. The catalyst is non corrosive and environmentally

friendly. This modern process features higher product yields, with a much lower capital

investment, than the environmentally outdated acid- based processes.

The unique catalytic distillation column combines reaction and fractionation in a single

unit operation. The alkylation reaction takes place isothermally and at low temperature. Reaction

products are continuously removed from the reaction zones by distillation. These factors limit the

formation of by-product impurities, enhance product purity and yields, and result in expected

reactor run lengths in excess of two years. Low operating temperatures result in lower equipment

design and operating pressures, which help to decrease capital investment, improve safety of

operations, and minimizing fugitive emissions. All waste heat, including the heat of reaction, is

recovered for improved energy efficiency.

The CD-cumene technology can process chemical or refinery grade propylene. It can also

use dilute propylene streams with purity as low as 10mol percent, provided the content of other

olefins and related impurities are within specification.

ZEOLITE CATALYST.

Except for the CDTech process, which combines catalytic reaction and distillation in a

single column, all zeolite-based processes consist of essentially the same flowsheet

configuration. The alkylation reaction is carried out in fixed-bed reactors at temperatures below

those used in SPA-based processes. When refinerygrade propylene is used as a feedstock, the

effluent from alkylation is sent to a depropanizer column that removes propane overhead. A

separate transalkylation reactor converts recycled PIPB and benzene to additional cumene. The



bottoms of the depropanizer are then mixed with the transalkylation reactor effluent and fed to a

series of three distillation columns. Benzene, product cumene, and PIPB are respectively

separated in the overhead of each column, with PIPB and benzene recycled to the reaction

system. A small stream of heavy aromatics is separated in the bottoms of the PIPB column. Like

the AlCl3 catalyst, zeolites are sufficiently active to transalkylate PIPB back to cumene. Overall

selectivity of benzene to cumene is quite high, varying from 99.7% to almost stoichiometric,

depending on the nature of the zeolite employed. Product purities as high as 99.97% can be

obtained, with B/P feed ratios between 3 and 5. A particular advantage of the zeolite catalysts is

that they are regenerable and can be used for several cycles. Therefore, the waste disposal

problems associated with SPA and AlCl3 catalysts are greatly reduced. In addition, carbon steel

can be used as the material of construction throughout the plant because of the mild operating

conditions and the absence of highly corrosive compounds. One limitation of the zeolite

technology is potential poisoning of the catalyst by contaminants in the feed.

Depending on feedstock quality, guard beds or additional feed pretreatment may thus be

required. If refinerygrade propylene is used, for example, its sulfur content must be closely

controlled.




PIPB Recycle

Cumene

Cumene Column

PIPB

Column

Heavies

Propane

Benzene

Propylene

Figure : CD- Cumene process

Transalkylator



Chapter 5

SELECTION OF PROCESS

5.1 ADVANTAGES

5.1.1 LIQUID PHASE ALKYLATION USING PHOSPHORIC ACID[2]

a) The SPA catalyst provides an essentially complete conversion of propylene on a one

pass basis.

b) Cumene product 99.9 wt% pure.

c) By product removal is relatively simple.

5.1.2 LIQUID PHASE ALKYLATION USING AlCl3[2]

a) Propane in propylene feed is recovered as liquid petroleum gas(LPG)

b) By product removal is relatively simple.

c) PAB may be recycled to the reactor as aluminium chloride has ability to

transalkylated PAB in presence of benzene.

5.1.3 Q-MAX PROCESS[1]

a) The catalyst in the both alkylation and Transalkylation reactor are regenerable.

b) The expected catalyst cycle is 2-4 years and the catalyst should not need replacement

for at least 3 cycles.

c) The Q-Max requires minimum pretreatment of feeds, which further minimizes the

capital costs.

5.1.4 CD- CUMENE PROCESS[1]

a) High selectivity and lower by product formation. High product yield; reduced plot

area.

b) Lower maintenance cost.

c) Decrease capital investment; improve safety and operability; applicable to conversion

of existing cumene plants.

d) Reduces utilities and operating cost; recover all waste heat and heat of reactions.



e) Improves economics – plant can be custom designed to process specific feed stocks

including the less expensive feedstock.

f) Continuous process.

g) Meets evolving environmental requirements.

h) Catalytic reaction and distillation is done in single column.

5.2 DISADVANTAGES

5.2.1 LIQUID PHASE ALKYLATION USING PHOSPHORIC ACID[2]

:

a) Cumene yield is limited to 95% because of the oligomerization of propylene and the

formation of heavy alykalate by-products.

b) The process requires a relatively high benzene propylene molar feed ratio on the

order of 7/1 to maintain cumene yield.

c) The catalyst is not regenerable and must be disposed at the end of each short catalyst

cycle.

5.2.2 LIQUID PHASE ALKYLATION USING ALUMINIUM CHLORIDE[2]

:

a) Feed pretreatment is required.

b) The presence of HCL in and around the reaction area can be troublesome; its

treatment is the major disadvantage of this process.

Q-Max Process and CD-Cumene process doesn’t have any disadvantage. But from

this two processes CD-Cumene process is more effective than Q-max process because,

a) Extends reactor run length over one year without regeneration, sustain high

conversion and selectivity.

b) Decrease capital investment, improves safety and operability.

c) Reduces utilities and operating costs, recovers all waste heat and heat of reaction.

d) Improves economics- plans can be custom designed to process specific feedstocks

including less expensive feedstock.

So that we are selecting CD-cumene process of manufacturing of CUMENE.



Chapter 6

THERMODYNAMIC FEASIBILITY

Table 6.a : Thermodynamic data

Component Cp (J/mol k) Entropy

@298(J/mol k)

∆Hf

@298(KJ/mol)

∆Gf

@298(KJ/mol)

Cumene 217.96 388.57 3.93 136.96

Propylene 115.3 266.6 20.42 62.72

Benzene 137.87 269.20 82.93 129.66

Chemical reaction

C3H6 + C6H6 → C9H12

Reaction temperature = 170

6.1 Calculation of heat of reaction at 443K

Hr = ∆Hf298 + ∫ ( )

– { ∫ ( )

+ ∫ ( )

}………………..[10]

Cp values are,[4]

Cp(cumene) = 124.62 + 6.392×10-1

T – 1.7331×10-3

T2 + 2.2146×10

-6T

3

Cp(propylene) = 54.718 + 3.4512×10-1

T – 1.6315×10-3

T2 + 3.8755×10

-6T

3

Cp(benzene) = −31.662 + 1.3043T – 3.6078×10-3

T2 + 3.8243×10

-6T

3

For Cumene

298∫443 (124.62+6.3293*10-1T-1.7331*10-3T2+2.2146*10-6T3)dT

= 18069.9 + 34002.58 – 34936.24 + 16956.92

= 34.093 KJ/mol



For Propylene

298∫443

(54.718 + 3.4512*10-1

T - 1.6315*10-3

T2

+ 3.8755*10-6

T3)dT

= 7934.11 + 18540.71 – 32888.16 + 29674.23

= 23.260 KJ/mol

For Benzene

298 ∫353

(-31.662 + 1.3043T – 3.6078*10-3

T2 + 3.8243*10

-6T

3)dT +30.75

= −4590.99 + 70070.25 – 72726.89 + 29282.21 + 30.75

= 22.065KJ/mol

Heat of formation at 298K

∆Hf298 = ∑ ∆Hf(product) − ∑ ∆Hf(reactant)………………[10]

= ∆Hf(cumene) – [∆Hf(propylene) +∆Hf(benzene) ]

= 3.93 – (20.42 + 82.93)

= −99.42KJ/mol

Heat of reaction at 443K

∆Hr443 = −99.42 + 34.093 – 23.260 – 22.065

= −110.652KJ/mol

Heat of reaction is negative, so the reaction is exothermic.



6.2 Calculation of Entropy

S443 = S298 +∫ (

)

……………………..[11]

= S298 + α ln(T2/T1) + β(T2− T1) – γ{ [1/(T2)2] – [1/(T1)

2] }

For Cumene

S443 = 388.57 + 124.621 ln(443/298) + 6.3293(443−298) +1.7331×10-3

×

[ (1/4432) –(1/298

2) ]

= 388.57 +49.401 + 917.74 – 1.068×10-8

= 1355.711J/mol

For propylene

S443 = 266.6 +54.718 ln(443/298) + 3.4512×10-1(443−298) + 1.6315×10

-3×

[ (1/4432) – (1/298

2) ]

= 266.6 +21.694 +50.04 − 1×10-8

= 338.334J/mol

For Benzene

S443 = 269.20 – 31.662 ln(443/298) + 1.3043×10^-1(443−298) + 3.6078×10-3

×

[ (1/4432) – (1/298

2) ]

= 269.20 – 12.55 +18.912 – 2.22×10-8

= 275.56J/mol



Entropy of reaction at 443k

∆S443 = ∑ S(product) − ∑ S(reactant) ……………………[11]

= 1355.711 – (338.334 +275.56)

=741.817J/mol

= 741.817×10-3

KJ/mol

6.3 calculation of Gibb’s free energy

∆G = ∆H − T∆S ……………………………………[11]

= −110.652 – [443×(741.817×10-3)]

= −439.27KJ/mol

Gibb’s free energy is negative, so the reaction is feasible.

6.4 Calculation of equilibrium constant

∆G = −RT ln(Kp) ………………………………...... [10]

Kp = (

)

=

= 1.12



Chapter 7

MATERIAL BALANCE

Plant capacity 300,000 ton / year.

Assuming 300 working days.

Basis- 1000 ton/ day cumene production

= 41666.67 kg/hr

= 346.67 kmol/hr

Reaction-

Main reaction:

C3H6 + C6H6 → C9H12

Side reaction:

C9H12 + C3H6 → C6H4( CH (CH3)2)2

Assuming 95% conversion is possible in reactor-1. Hence 90% of cumene get converted into

cumene and 5% propylene get reacted with cumene to form PIPB.

Propylene fed = 346.67 kmol/hr

Benzene to propylene feed ratio is 4:1.

Benzene fed = 1400 kmol/hr

Propylene reacted = 0.95 * 346.67

= 329.33 kmol/hr

Unreacted propylene = 346.67 – 329.33

= 17.34 kmol/hr

Benzene reacted = 0.9 * 346.67

= 312 kmol/hr



Since the reaction is exothermic.

Hence heat evolved in CD-column is

= 0.95 * propylene feed * heat of reaction

= 0.95 * 346.67 * 96.428

= 31757.26 kJ

Benzene evaporated = (total heat evolved) / (latent heat of benzene)

= (31757.26) / (30.75)

= 1032.75 kmol

Benzene fed into CD-column = benzene evaporated in CD-column + benzene reacted

= 1032.75 + 312

= 1344.75 kmol/hr

Unreacted benzene = 1344.75 – 312

= 1032.75 kmol/hr

Cumene produced = 312kmol/hr

But 5% of propylene reacts with the cumene and produce PIPB (it contains DIPB and little

amount of TIPB)

Cumene produced = 312 – 0.05 * 346.67

= 294.67 kmol/hr

Cumene produced in finishing reactor = 0.05 * 346.67

= 17.33 kmol/hr

From given,

Selectivity of propylene to cumene = 81.7

Benzene reacted with DIPB to produce cumene = 0.05 * 346.67

= 17.33 kmol/hr

DIPB produced = 0.98 * 17.33



= 16.98 kmol/hr

Net amount cumene produced = 312 + 17.33 + 16.98

= 346.31kmol/hr

PIPB produced = 0.02 * 17.33

= 0.3466 kmol/hr

Material balance of cumene column: cumene 346.31 Kmol/hr

Cumene + DIPB

346.31 Kmol/hr + 17.33 Kmol/hr

DIPB 17.33 Kmol/hr

Material balance of DIPB column:

DIPB 16.9834 Kmol/hr

DIPB

17.33 Kmol/hr

Heavy ends

0.3466 Kmol/hr



Material balance of transalkylation reactor:

Cumene 16.9834Kmol/hr

Benzene + PIPB

16.9834 Kmol/hr +16.9834Kmol/hr

Material balance for finishing reactor:

Benzene = 17.33 kmol/hr

cumene = 17.33 kmol/hr

propylene = 17.33 kmol/hr



Chapter 8

ENERGY BALANCE

Plant capacity is 300,000 ton / year. Assuming 300 working day .

Basis = 1000 ton of cumene per day

= 346.67 kmol/hr

Cp values data:

Component A B C D

Cumene 10.149 5.1138E-1 -1.7703E-5 -2.2612E-7

Propylene 31.298 7.2449E-1 1.9481E-4 -2.1582E-7

Benzene -31.368 4.7460E-1 -3.1137E-4 8.5237E-8

Energy balance on CD-column –

Benzene unreacted benzene + propylene

propylene cumene + PIPB

Cumene synthesis is exothermic reaction.

The heat given out when 1mol propylene reacted is the heat of reaction = 96.428 kJ

Hence total heat given out = 33393.98 kJ/hr

This amount of heat is taken out of reaction zone by evaporation of benzene. This vapour phase

benzene is then cooled and bring to liquid phase. Hence heat taken out in condenser is,

Condenser load = 33393.98 kJ/hr



Energy balance on cumene column –

: Cumene

Cumene + DIPB

DIPB

The cumene with PIPB comes out from CD-column at 152 C. This mixture is heated to near

about 170 C to distill out cumene from the PIPB column.

Heat load on reboiler = mCp∆T

= [346.67 * 217.96 * (170-152)] + [17.33 * 382.42 * (170-152)]

= 1477.96 * 103 kJ/hr

The cumene is cooled to liquid phase,

Load on condenser = mCp(35-170)

= 346.67 * 217.96 * (35-170)

= 10200.63 * 103 kJ/hr



Energy balance on PIPB column-

DIPB

DIPB

Heavy ends

PIPB comes out from cumene column is separated in DIPB and heavier ends, for this separation

mixture is heated to 200 c.

Reboiler load = 17.33 * 382.42 * (200-170)

= 1988.35 * 102 kJ/hr

Energy balance on transalkylation reactor-

Cumene

Benzene + PIPB

In this unit producing cumene from DIPB and benzene. Since reaction is exothermic.

The net heat given out from the reaction = 96.428 * 17.33

= 1671.09 kJ/hr

Condenser load = 1671.09 kJ/hr



Chapter 9

DESIGN OF MULTICOMPONENT DISTILLATION COLUMN

Assume 99% benzene is separated as a overhead & 99.5% cumene is separated as bottom

product

In our case

1. Propylene lighter than light key

2. Benzene light key

3. Cumene heavy key

4. PIPB heavier than heavy key

Material balance

Component Feed Distllate Bottom

Moles Mol.

Fraction

Mol Mol

fraction

Mol Mol

fraction

Propylene 17.34 0.0123 17.34 0.0166 - -

Benzene 1032.75 0.721 1022.42 0.98 10.33 0.0277

Cumene 346.31 0.245 1.732 0..166 344.58 0.926

DIPB 17.33 0.0122 - - 17.33 0.0465

Total 1413.73 372.24

Vapor pressure data

Log p = A- B/(T+C)

Calculation of top temperature

Component yi pi ki xi = yi/ki

Propylene 0.0166 31627.13 17.15 0.000968

Benzene 0.98 927.68 1 0.98

Cumene 0.00166 96.31 0.09 0.018

0.999

Top temperature = 870C



Calculation of bottom temperature

Component Xi Pi ki yi = kixi

Propylene 0.0277 4521.18 5.43 0.150411

Benzene 0.926 733.30 0.9 0.8334

Cumene 0.0465 185.11 0.188 0.008742

0.993

Bottom temp = 152 0

C

Nmin = (

) (

)

= (

)(

)

= 3.67

Minimum reflux ratio

Lower pinch temperature = column top temp. +

(temp. of bottom- temp of top)

= 87 +

(152-87)

= 130.33

Upper pinch temperature = column top temp. +

(temp. of bottom- temp of top)

= 87 +

(152-87)

= 108.67

Component Vapour

pressure at

108.67

Αi Vapour

pressure at

130.33

αi αavg

Propylene 45881.14 219.17 64840.97 158.53 186.4

Benzene 1684.86 8.05 2865.66 7.0 7.51

Cumene 209.34 1.0 409.01 1.0 1.0

DIPB 38.91 0.186 89.26 0.218 0.2



The minimum reflux ratio can be calculated by underwood’s method

RRmin + 1 =

…………for all component.

= 1 – q

The feed line is a saturated liquid at its boiling point, so q = 1.

By trial and error method,

θ lies between, αB < θ < αA

αA = 7.51 αB = 1

1 < θ < 7.51

Trial and error method

Θ L.H.S R.H.S ∆= L.H.S – R.H.S

7 10.58 0.000358 10.579642

5 2.1 0.000508 2.099492

1.2 -0.354 0.00244 -0.356

2 0.749 0.001355 0.74

1.5 0.423 0.00187 0.421

R Rmin = 0.238

Assume,

= 1.5

R = 1.5 * 0.238

= 0.367

= (0.238/1.238)

= 0.2

= (0.36/1.36)

= 0.264



From, fig.9.4, Erbar – Maddox correlation (

vs

)

= 0.38

N =

= 9.66

= 10

Assuming 50 % efficiency of stages

Theoretical no of stages =

= 20

The Principal factor that determine the tower diameter is the gas ( vapour) velocity. It

is the flooding condition that fixes the upper limit of gas ( vapour) velocity. The flooding

velocity is given by

vfl = (

)0.5

Where Vfl = flooding velocity of gas ( vapour )

K = constant

ρl , ρv = density of liquid & vapour respectively

here , ρ = 2.7 Kg/ m3

ρ = 862 Kg/ m3

Assuming plate spacing 0.45m

from fig 9.1 K = 0.08

vfl = 1.42 m/s.

Assuming 85% flooding condition

Vfl = 0.85 × 1.42

= 1.21 m/s.



Maximum flow rate

Vmax

=

= 8.36 m/s

Net area required = An

=

=

= 5.88 m2.

An = At – Ad

= At – 0.12At

= 0.88At

At =

= 6.68 m2

Column diameter

Dt = √

= √

= 2.91 m



LIQUID FLOW PATTERN:

Liquid flow pattern is determined by two parameters

1. Maximum liquid flowrate

2. Column diameter

Here , Lmax =

= 0.0238 m3/s

Hole area, Ah = 10% of active area

Aa = At – 2Ad

= 6.68 – 2 × 0.80

= 5.08 m2

Ah = 0.10 × 5.08

= 0.508 m2

Weir length = 0.77 × Dt

= 0.77 × 2.91

= 2.24 m

Let’s take

Hole diameter = 7 mm

Plate thickness= 5 mm



PLATE DESIGN:

Column diameter = 2.91 m

Column cross section ,

At = 6.68 m2

Weir Height :

Since column operating at pressure above atmospheric pressure,

hw = 50 mm

Plate thickness = 5 mm

CROSS CHECK:( FOR PLATE DIMENSIONS)

Maximum Liquid rate = 23.12 kg/s

Assuming turndown ratio at 70% of maximum liquid flowrate ,

so that minimum liquid flowrate =

*23.12 =16.184 kg/s.

The height of liquid crest over the segmental weir:

(how)max = 0.70 (

)(2/3)

= 36 mm of clear liquid

(how)min = 0.75 (

)(2/3)


At minimum flowrate, dh

hw + how = 50+30=80 mm



from fig 9.2, Kw = 30.2

therefore minimum vapour velocity,

vmin =

√ ( ( ))

vmin =

√ ( ( ))

= 7.20 m/s

But actual vapour velocity

=

=

= 9.92 m/s.

Thus the minimum operating velocity (9.92 m/s) lies well above the weep point (i.e. when

vapour velocity = 7.20 m/s)

Therefore our design is safe from operating point of view

Plate pressure drop :

The total plate pressure drop is given by,

ht = hd + hl + hr

dry plate drop

hd = K1+ K2 (vgh)2 (

)

for sieve plate ,

K1=0,

K2=



Discharge coefficient Cv is determined as follows,

From fig.9.3, Cv= 0.765

Velocity through holes

Vgh =

hd = 50.85*10-3 (

) (

)

= 3.42 mm of clear liquid

Pressure drop due to staric liquid head,

hl = hw + how

= 50+36


Residual head,

hr =

=


The total pressure drop

ht = hd + hl + hr

= 3.42 + 86 + 14




Downcomer area backup :

Backup in downcomer is given by,

Hdc = ht + hw + how + hda

Head loss in the downcomer due to liquid flow under the downcomer apron :

hda = 0.166*(

)

now,

Aap = hap*lw

Hap= height of lower edge of the apron above the tray

= hw – 10 = 50 – 10 =40 mm

Lw = 2.24 m

Aap = Area under the downcomer apron

= 0.04 * 2.24

= 0.0896 m2

Since Aap < Ad we take Ad as Am

hda = 0.166 (

)2


Hdc = 103.42+ 50 +36 + 1.12




Check :

To avoid flooding :

Hdc <

( )

Now ,

( )

( )

Since hdc < 0.250m ,so there will be no flooding at specified operating condition that means tray

spacing is acceptable.

Residence time :

Τr =

=

= 5.68 s.

Total height of tower

= [no of plates * tray spacing] + clearance at top + clearance at bottom

= [20 * 0.5] + 0.5 + 0.5

= 10 m

So the design is satisfactory.



SHELL THICKNESS :

For thickness of shell of distillation column we required following data,

1. Design Pressure, P = 1.1 * operating pressure

= 1.1 * 2.757

= 3.0327 N/mm2

2. Permissible tensile stress, f = 95 N/mm2 ( MOC= CARBON STEEL)

3. Joint efficiency facor , J = 0.85

4. Inner diameter, Di =2.91 m

5. Corrosion allowance, C = 1.5 mm

Shell thickness is given by,

ts=

–

ts =

ts = 57.19 mm

Head thickness :

for safety we use hemispherical head at top & bottom of distillation column. The head

thickness is given by ,

th =

th =

th = 23 mm











Chapter 10

COST ESTIMATION

Cost of cumene plant of capacity 400 TPD in 1990 is Rs.23.4×107

Therefore cost of 1000 TPD in 1990 is:

C1 = C2 (Q1/Q2)0.6

= 23.4 x 107(1000/400)

0.6

= Rs.4.055 x 108

Chemical Engineering Plant Cost Index:

Cost index in 1990 = 357.6

Cost index in 2010 = 539.1

Thus, Present cost of Plant = (original cost) × (present cost index)/(past cost index)

= (4.055 x 108) × (539.1/357.6)

= Rs. 6.113×108

Fixed Capital Cost (FCI) = Rs. 6.113×108

Estimation of Capital Investment Cost:

I. Direct Costs: material and labour involved in actual installation of complete facility (70-85%

of fixed-capital investment)

a) Equipment + installation + instrumentation + piping + electrical + insulation + painting (50-

60% of Fixed-capital investment)

1. Purchased equipment cost (PEC): (15-40% of Fixed-capital investment)

Consider purchased equipment cost = 25% of Fixed-capital investment

PEC = 25% of 6.113×108

= 0.25 × 6.113×108

= Rs. 1.528×108

2. Installation, including insulation and painting: (25-55% of purchased equipment cost.)

Consider the Installation cost = 40% of Purchased equipment cost



= 40% of 1.528×108

= 0.40 ×1.528×108

= Rs.0.6112×10

8

3. Instrumentation and controls, installed: (6-30% of Purchased equipment cost.)

Consider the installation cost = 20% of Purchased equipment cost

= 20% of ×1.528x108

= 0.20 ×1.528×108

= Rs. 0.3056×108

4. Piping installed: (10-80% of Purchased equipment cost)

Consider the piping cost = 40% Purchased equipment cost

= 0.40 ×1.528×108

= Rs. 0.6112×108

5. Electrical, installed: (10-40% of Purchased equipment cost)

Consider Electrical cost = 25% of Purchased equipment cost

= 25% of 1.528 ×108

= 0.25 ×1.528×108

= Rs.0.382×108

B. Buildings, process and Auxiliary: (10-70% of Purchased equipment cost

Consider Buildings, process and auxiliary cost,

= 40% of PEC

= 40% of 1.528 ×108

= 0.40 ×1.528×108

= Rs. 0.6112×108



C. Service facilities and yard improvements: (40-100% of Purchased equipment cost)

Consider the cost of service facilities and yard improvement,

= 60% of PEC

= 60% of 1.528 ×108

= 0.60 ×1.528×10

8

= Rs. 0.9168×10

8

D. Land: (1-2% of fixed capital investment or 4-8% of Purchased equipment cost)

Consider the cost of land = 6% PEC

= 6% of 1.528 ×108

= 0.06 ×1.528×108

= Rs. 0.09168×10

8

Thus, Direct cost = Rs. 5.058×108 ----- (82.74% of FCI)

II. Indirect costs: expenses which are not directly involved with material and labour of actual

installation of complete facility (15-30% of Fixed-capital investment)

A. Engineering and Supervision: (5-30% of direct costs)

Consider the cost of engineering and supervision,

= 10% of Direct costs

= 10% of 5.058 ×108

= 0.1× 5.058 ×108

= Rs.0.5058×108

B. Construction Expense and Contractor’s fee: (6-30% of direct costs)

Consider the construction expense and contractor’s fee,

= 10% of Direct costs

= 10% of 5.058×108

= 0.1× 5.058 ×108



= 0.5058×10

8

C. Contingency: (5-15% of Fixed-capital investment)

Consider the contingency cost = 10% of Fixed-capital investment

= 12% of 6.113×108

= 0.12 × 6.113×108

= Rs. 0.7336×108

Thus, Indirect Costs = Rs. 1.7452×108 --- (28.55% of FCI)

III. Fixed Capital Investment:

Fixed capital investment = Direct costs + Indirect costs

= (5.058×108) + (1.7452×10

8)

= Rs. 6.803×108

IV. Working Capital: (10-20% of Fixed-capital investment)

Consider the Working Capital = 15% of Fixed-capital investment.

= 15% of 6.803×108

= 0.15 × 6.803×108

= Rs. 1.0205×10

8

V. Total Capital Investment (TCI):

Total capital investment = Fixed capital investment + Working capital

= (6.803×108) + (1.0205×10

8)

= Rs. 7.8235×108

Estimation of Total Product cost:

I. Manufacturing Cost = Direct production cost + Fixed charges + Plant overhead cost.

A. Fixed Charges: (10-20% total product cost)

i. Depreciation: (13% of FCI for machinery and equipment and 2-3% for Building Value for)

Consider depreciation = 13% of FCI



Depreciation = (0.13×6.803×108) + (0.03×0.6112×10

8)

= Rs. 0.9027×108

ii. Local Taxes: (1-4% of fixed capital investment)

Consider the local taxes = 3% of fixed capital investment

= 0.03×6.803×108

= Rs. 0.2041×108

iii. Insurances: (0.4-1% of fixed capital investment)

Consider the Insurance = 0.7% of fixed capital investment

= 0.007×6.803×108

= Rs. 0.0476×108

iv. Rent: (8-12% of value of rented land and buildings)

Consider rent = 10% of value of rented land and buildings

= 10% of ((0.09168×108) + (0.6112×10

8))

= Rs. 0.0703x108

Thus, Fixed Charges = Rs. 1.2247×108

B. Direct Production Cost: (about 60% of total product cost)

Now we have Fixed charges = 10-20% of total product charges – (given)

Consider the Fixed charges = 15% of total product cost

Total product charge = fixed charges/15%

= 1.2247×108/15%

= 1.2247×108/0.15

= Rs. 8.1647×108

i. Raw Materials: (10-50% of total product cost)

Consider the cost of raw materials,

= 25% of total product cost



Raw material cost = 25% of 8.1647×108

= 0.25×8.1647×108

= Rs. 2.0412×108

ii. Operating Labour (OL): (10-20% of total product cost)

Consider the cost of operating labour,


= 12% of 8.1647×108

= 0.12×8.1647×108

= Rs. 0.9797×108

iii. Direct Supervisory and Clerical Labour (DS & CL): (10-25% of OL)

Consider the cost for Direct supervisory and clerical labour,

= 12% of OL

= 12% of 0.9797×108

= 0.12×0.9797×108

= Rs. 0.1176×108

iv. Utilities: (10-20% of total product cost)

Consider the cost of Utilities,


= 12% of 8.1647×108

= 0.12×8.1647×108

= Rs. 0.9797×108

v. Maintenance and repairs (M & R): (2-10% of fixed capital investment)

Consider the maintenance and repair cost,

= 5% of fixed capital investment



= 0.05×6.803×108

= Rs. 0.3402×108

vi. Operating Supplies: (10-20% of M & R or 0.5-1% of FCI)

Consider the cost of Operating supplies,

= 15% of M & R

= 15% of 0.3402×108

= 0.15 ×0.3402×108

= Rs. 0.05103×108

vii. Laboratory Charges: (10-20% of OL)

Consider the Laboratory charges,

= 15% of OL

= 15% of 0.9797×108

= 0.15×0.9797×108

= Rs. 0.1469×108

viii. Patent and Royalties: (0-6% of total product cost)

Consider the cost of Patent and royalties,


= 4% of 8.1647×108

= 0.04×8.1647×108

= Rs. 0.3266×108

Direct Production Cost = Rs. 4.983×108 ----- (61% of TPC)

C. Plant overhead Costs (50-70% of Operating labour, supervision, and maintenance or 5-15%

of total product cost); includes for the following: general plant upkeep and overhead, payroll

overhead, packaging, medical services, safety and protection, restaurants, recreation, salvage,

laboratories, and storage facilities.



Consider the plant overhead cost,

= 60% of OL, DS & CL, and M & R

= 60% of ((0.9797×108) + (0.1176×10

8) + (0.3402×10

8))

= Rs. 0.8625×108

Thus,Manufacture cost = Direct production cost + Fixed charges + Plant overhead costs.

Manufacture cost = (4.983×108) + (6.803×10

8) + (0.8625×10

8)

Manufacture cost = Rs. 12.6485×108

II. General Expenses = Administrative costs + distribution and selling costs + research and

development costs

A. Administrative costs:(2-6% of total product cost)

Consider the Administrative costs ,


= 0.05 ×8.1647×108

= Rs. 0.4082×108

B. Distribution and Selling costs: (2-20% of total product cost); includes costs for sales

offices, salesmen, shipping, and advertising.

Consider the Distribution and selling costs,


= 15% of 8.1647×108

= 0.15 ×8.1647×108

= Rs. 1.2247×108

C. Research and Development costs: (about 5% of total product cost)

Consider the Research and development costs,


= 5% of 8.1647×108



= 0.05 × 8.1647×108

= Rs. 0.4082×108

D. Financing (interest): (0-10% of total capital investment)

Consider interest = 5% of total capital investment

= 5% of 7.8235×108

= 0.05×7.8235×108

= Rs. 0.3912×108

= Rs. 2.4323×108

IV. Total Product cost = Manufacture cost + General Expenses

= (12.6485×108) + (2.4323×10

8)

= Rs. 15.0808×108

V. Gross Earnings/Income:

Wholesale Selling Price of cumene per kg = Rs.53

Total Income = Selling price × Quantity of product manufactured

= 53 x 30000000

= Rs. 15.9×108

Gross income = Total Income – Total capital investment

= (15.9×108) – (8.1647×10

8)

= Rs. 7.7353×108

Let the Tax rate be 45% (common)

Net Profit = Gross income - Taxes

= Gross income× (1- Tax rate)

= 7.7353 x 108(1-0.45)

= Rs. 4.2544×108



Pay back period = FCI/(net profit)

= 6.803*108/4.2544*10

8

= 1.6.

Rate of return = net profit* 100/(total capital investment)

= 4.2544*108*100

/ 7.8235*10

8

= 54.38 %



Chapter 12

ENVIRONMENTAL AND HAZOP STUDY

Environmental Considerations:

Vigilance is required in both the design and operation of process plant to ensure that legal

standards are met and that no harm is done to the environment. Considerations must be given to:

(1) All emissions to land, air, water.

(2) Waste management.

(3) Smells.

(4) Noise.

(5) The visual impact.

(6) Any other nuisances.

(7) The environmental friendliness of the products.

Waste Management:

Waste arises mainly as by products or unused reactants from the process, or as off- specification

product produced through mis-operation.

Gaseous Waste:

Gaseous effluents which contain toxic or noxious substances will need treatment before

discharge into the atmosphere. Gaseous pollutants can be removed by absorbtion or adsorbtion.

Finely dispersed solids can be removed by scrubbing, or using electrostatic precipitators.

Flammable gases can be burnt.

Liquid Waste:

The waste liquids from a chemical process, other than aqueous effluents will usually be

flammable and can be disposed of by burning in suitable designed incinerators. The gases

leaving an incinerator may be scrubbed, & acid gases neutralized.

Aqueous Waste:

The principal factors which determine the nature of an aqueous industrial effluent and on which

strict controls will be placed by the responsible authority are:

(1) pH.

(2) Suspended solid.

(3) Toxicity.

(4) Biological oxygen demand.



The pH can be adjusted by the addition of acid or alkali. Lime is frequently used to neutralize

acidic effluents. Suspended solids can be removed by settling, using clarifiers. For some

effluents it will be possible to reduce the toxicity to acceptable level by dilution. Other effluents

will need chemical treatment. The oxygen concentration on water course must be maintained at a

level sufficient to support aquatic life. It is measured by a standard BOD test.

Toxicological data:

The toxicological data for a cumene plant is usually supposed to have the following values on the

various environmental parameters as given below: Threshold limit value 50 ppm, Skin effects

primary irritant, Absorption through skin slowly absorbed, Narcotic properties yes, Depressant

properties yes. Medical examination for workers required in some countries Other precautions as

for all aromatics.

Noise:

It can cause a serious nuisance in the neighbourhood of a process plant. Noisy equipment should,

as far as practicable, be sited well away from the site boundary. Earth banks and screens of trees

can be used to reduce the noise level perceived outside the site.

Visual Impact:

Large equipments such as storage tanks, can be painted to blend in with, or even contrast with,

the surroundings. Landscaping and screening by belts of trees can also help improve the overall

appearance of the site.

11.1 MATERIAL SAFETY DATA SHEET

11.1.1 HAZARDS IDENTIFICATION

Inhalation -

Breathing high concentrations may be harmful. Mist or vapor can irritate the throat and lungs.

Breathing this material may cause central nervous system depression with symptoms including

nausea, headache, dizziness, fatigue, drowsiness, or unconsciousness.

Eye Contact -

This material can cause eye irritation with tearing, redness, or a stinging or burning feeling.

Further, it can cause swelling of the eyes with blurred vision. Effects may become more serious

with repeated or prolonged contact.

Skin Contact -



May cause mild skin irritation with redness and/or an itching or burning feeling. Effects may

become more serious with repeated or prolonged contact. It is likely that some components of

this material are able to pass into the body through the skin and may cause similar effects as from

breathing or swallowing it.

Ingestion -

Swallowing this material may be harmful. Swallowing this material may cause stomach or

intestinal upset with pain, nausea, and/or diarrhea. This material can get into the lungs during

swallowing or vomiting. Small amounts in the lungs can cause lung damage, possibly leading to

chronic lung dysfunction or death. Swallowing this material may cause effects.

Chronic Health Effects Summary -

Secondary effects of ingestion and subsequent aspiration into the lungs may cause pneumatocele

(lung cavity) formation and chronic lung dysfunction.

Conditions Aggravated by Exposure -

Disorders of the following organs or organ systems that may be aggravated by significant

exposure to this material or its components include: Skin, Respiratory System, Central Nervous

System (CNS).

Target Organs –

May cause damage to the following organs: kidneys, liver, mucous membranes, spleen, upper

respiratory tract, skin, adrenal, central nervous system (CNS), eye, lens or cornea.

Carcinogenic Potential –

This product is not known to contain any components at concentrations above 0.1% which are

considered carcinogenic by OSHA, IARC or NTP.

11.1.2 FIRST AID MEASURES

Take proper precautions to ensure your own health and safety before attempting rescue or

providing first aid.

Inhalation –

Move victim to fresh air. If victim is not breathing, immediately begin rescue breathing. If

breathing is difficult, 100 percent humidified oxygen should be administered by a qualified

individual. Seek medical attention immediately. Keep the affected individual warm and at rest.



Eye Contact –

Check for and remove contact lenses. Flush eyes with cool, clean, low-pressure water for at least

15 minutes while occasionally lifting and lowering eyelids. Do not use eye ointment unless

directed to by a physician. Seek medical attention if excessive tearing, irritation, or pain persists.

Skin Contact –

Remove contaminated shoes and clothing. Flush affected area with large amounts of water. If

skin surface is damaged, apply a clean dressing and seek medical attention. Do not use

ointments. If skin surface is not damaged, clean affected area thoroughly with mild soap and

water. Seek medical attention if tissue appears damaged or if pain or irritation persists.

Ingestion –

Do not induce vomiting. If spontaneous vomiting is about to occur, place victim’s head below

knees. If victim is drowsy or unconscious, place on the left side with head down. Never give

anything by mouth to a person who is not fully conscious. Do not leave victim unattended. Seek

medical attention immediately.

11.1.3 FIRE FIGHTING MEASURES

NFPA Flammability Classification - NFPA Class-IC flammable liquid.

Flash Point - Closed cup: 36°C (96°F). (Pensky-Martens.)

Lower Flammable Limit - AP 0.9 %

Upper Flammable Limit - AP 6.5 %

Autoignition Temperature - 424°C (795°F)

Hazardous Combustion Products - Carbon dioxide, carbon monoxide, smoke, fumes, and/or

unburned hydrocarbons.

Special Properties –

This material releases vapors at or below ambient temperatures. When mixed with air in certain

proportions and exposed to an ignition source, its vapor can cause a flash fire. Use only with

adequate ventilation. Vapors are heavier than air and may travel long distances along the ground

to an ignition source and flash back. A vapor and air mixture can create an explosion hazard in

confined spaces such as sewers. If container is not properly cooled, it can rupture in the heat of a

fire.



Extinguishing Media –

SMALL FIRE: Use dry chemicals, carbon dioxide, foam, water fog, or inert gas (nitrogen).

LARGE FIRE: Use foam, water fog, or water spray. Water fog and spray are effective in

cooling containers and adjacent structures. However, water can cause frothing and/or may not

extinguish the fire. Water can be used to cool the external walls of vessels to prevent excessive

pressure, autoignition or explosion. Do not use a solid stream of water directly on the fire as the

water may spread the fire to a larger area.

Protection of Fire fighters –

Firefighters must use full bunker gear including NIOSH-approved positive pressure self-

contained breathing apparatus to protect against potential hazardous combustion or

decomposition products and oxygen deficiencies. Evacuate area and fight the fire from a

maximum distance or use unmanned hose holders or monitor nozzles. Cover pooling liquid with

foam. Containers can build pressure if exposed to radiant heat; cool adjacent containers with

flooding quantities of water until well after the fire is out. Withdraw immediately from the area

if there is a rising sound from a venting safety device or discoloration of vessels, tanks, or

pipelines. Be aware that burning liquid will float on water. Notify appropriate authorities of

potential fire and explosion hazard if liquid enter sewers or waterways.

11.1.4 ACCIDENTAL RELEASE MEASURES

Flammable Liquid! Release causes an immediate fire or explosion hazard. Evacuate all non-

essential personnel from immediate area and establish a "regulated zone" with site control and

security. A vapor-suppressing foam may be used to reduce vapors. Eliminate all ignition sources.

All equipment used when handling this material must be grounded. Stop the leak if it can done

without risk. Do not touch or walk through spilled material. Remove spillage immediately from

hard, smooth walking areas.Prevent spilled material from entering waterways, sewers,

basements, or confined areas. Absorb or cover with dry earth, sand, or other non-combustible

material and transfer to appropriate waste containers. Use clean, non-sparking tools to collect

absorbed material. For large spills, secure the area and control access. Prevent spilled material

from entering sewers, storm drains, other drainage systems, and natural waterways. Dike far

ahead of a liquid spill to ensure complete collection. Water mist or spray may be used to reduce

or disperse vapors; but, it may not prevent ignition in closed spaces. This material will float on

water and its run-off may create an explosion or fire hazard. Verify that responders are properly



HAZWOPER-trained and wearing appropriate respiratory equipment and fire-resistant protective

clothing during cleanup operations. In an urban area, cleanup spill as soon as possible; in natural

environments, cleanup on advice from specialists. Pick up freeliquid for recycle and/or disposal

if it can be accomplished safely with explosion-proof equipment. Collect any excess material

with absorbant pads, sand, or other inert non-combustible absorbent materials. Place into

appropriate waste containers for later disposal. Comply with all applicable local, state and

federal laws and regulations.

11.1.5 HANDLING AND STORAGE

Handling

A spill or leak can cause an immediate fire or explosion hazard. Keep containers closed and do

not handle or store near heat, sparks, or any other potential ignition sources. Avoid contact with

oxidizing agents. Do not breathe vapor. Use only with adequate ventilation and personal

protection. Never siphon by mouth. Avoid contact with eyes, skin, and clothing. Prevent contact

with food and tobacco products. Do not take internally. When performing repairs and

maintenance on contaminated equipment, keep unnecessary persons away from the area.

Eliminate all potential ignition sources. Drain and purge equipment, as necessary, to remove

material residues. Follow proper entry procedures, including compliance with 29 CFR 1910.146

prior to entering confined spaces such as tanks or pits. Use gloves constructed of impervious

materials and protective clothing if direct contact is anticipated. Use appropriate respiratory

protection when concentrations exceed any established occupational exposure level Promptly

remove contaminated clothing. Wash exposed skin thoroughly with soap and water after

handling. Non-equilibrium conditions may increase the fire hazard associated with this product.

A static electrical charge can accumulate when this material is flowing through pipes, nozzles or

filters and when it is agitated. A static spark discharge can ignite accumulated vapors

particularly during dry weather conditions. Always bond receiving containers to the fill pipe

before and during loading. Always confirm that receiving container is properly grounded.

Bonding and grounding alone may be inadequate to eliminate fire and explosion hazards

associated with electrostatic charges. Carefully review operations that may increase the risks

associated with static electricity such as tank and container filling, tank cleaning, sampling,

gauging, loading, filtering, mixing, agitation, etc. In addition to bonding and grounding, efforts

to mitigate the hazards of an electrostatic discharge may include, but are not limited to,



ventilation, inerting and/or reduction of transfer velocities. Dissipation of electrostatic charges

may be improved with the use of conductivity additives when used with other mitigation efforts,

including bonding and grounding. Always keep nozzle in contact with the container throughout

the loading process. Do not fill any portable container in or on a vehicle. Do not use compressed

air for filling, discharging or other handling operations. Product container is not designed for

elevated pressure. Do not pressurize, cut, weld, braze solder, drill, or grind on containers. Do not

expose product containers to flames, sparks, heat or other potential ignition sources. Empty

containers may contain material residues which can ignite with explosive force. Observe label

precautions.

Storage

Keep container tightly closed. Store in a cool, dry, well-ventilated area. Store only in approved

containers. Do not store with oxidizing agents. Do not store at elevated temperatures or in direct

sunlight. Protect containers against physical damage. Head spaces in tanks and other containers

may contain a mixture of air and vapor in the flammable range. Vapor may be ignited by static

discharge. Storage area must meet OSHA requirements and applicable fire codes. Additional

information regarding the design and control of hazards associated with the handling and storage

of flammable and combustible liquids may be found in professional and industrial documents

including, but not limited to, the National Fire Protection Association (NFPA) publications

NFPA 30 ("Flammable and Combustible Liquid Code"), NFPA 77 ("Recommended Practice on

Static Electricity") and the American Petroleum Institute (API) Recommended Practice 2003,

(“Protection Against Ignitions Arising Out of Static, Lightning, and Stray Currents"). Consult

appropriate federal, state and local authorities before reusing, reconditioning, reclaiming,

recycling or disposing of empty containers or waste residues of this product.

11.1.6 EXPOSURE CONTROLS AND PERSONAL PROTECTION

Engineering Controls

Provide ventilation or other engineering controls to keep the airborne concentrations of vapor or

mists below the applicable workplace exposure limits indicated below. All electrical equipment

should comply with the National Electrical Code. An emergency eye wash station and safety

shower should be located near the work-station.



Personal Protective Equipment

Personal protective equipment should be selected based upon the conditions under which this

material is used. A hazard assessment of the work area for PPE requirements should be

conducted by a qualified professional pursuant to OSHA regulations. The following pictograms

represent the minimum requirements for personal protective equipment. For certain operations,

additional PPE may be required.

Eye Protection

Safety glasses equipped with side shields are recommended as minimum protection in industrial

settings. Chemical goggles should be worn during transfer operations or when there is a

likelihood of misting, splashing, or spraying of this material. A suitable emergency eye wash

water and safety shower should be located near the work station.

Hand Protection

Avoid skin contact. Use heavy duty gloves constructed of chemical resistant materials such as

Viton® or heavy nitrile rubber. Wash hands with plenty of mild soap and water before eating,

drinking, smoking, use of toilet facilities or leaving work. Do not use gasoline, kerosene,

solvents or harsh abrasives as skin cleaners.

Body Protection

Avoid skin contact. Wear long-sleeved fire-retardant garments (e.g., Nomex®) while working

with flammable and combustible liquids. Additional chemical-resistant protective gear may be

required if splashing or spraying conditions exist. This may include an apron, boots and

additional facial protection. If product comes in contact with clothing, immediately remove

soaked clothing and shower. Promptly remove and discard contaminated leather goods.

Respiratory Protection

For known vapor concentrations above the occupational exposure guidelines (see below), use a

NIOSH-approved organic vapor respirator if adequate protection is provided. Protection factors

vary depending upon the type of respirator used. Respirators should be used in accordance with

OSHA requirements (29 CFR 1910.134).

General Comments

Use of this material in spaces without adequate ventilation may result in generation of hazardous

levels of combustion products and/or inadequate oxygen levels forbreathing. Odor is an

inadequate warning for hazardous conditions.



10.1.7 STABILITY AND REACTIVITY

Chemical Stability - Normally stable but may form peroxides when stored for prolonged time

periods in contact with air.

Conditions to Avoid - Keep away from heat, sparks and flame. Forms peroxides with

prolonged storage.

Materials Incompatibility -Strong acids, alkalies, and oxidizers..

10.1.8 TOXICOLOGICAL INFORMATION

Toxicity Data –

Effects from Acute Exposure:

Overexposure to cumene may cause upper respiratory tract irritation and severe CNS depression.

Effects from Prolonged or Repeated Exposure:

High-level exposure to cumene vapors significantly increases renal tubule adenoma in male rats.

Furthermore this exposure is associated with increased alveolar/broncheolar adenoma and

carcinoma in mice and with increased hepatocellular carcinoma in female mice. At this time the

relevance of these finds to human health are not clear.

10.1.9 ECOLOGICAL INFORMATION

Ecotoxicity - LC50 (fish): 1- 10 mg/l. This product is potentially toxic to freshwater and

saltwater ecosystems.

Environmental Fate - This product will normally float on water. Components will evaporate

rapidly. Aquatic toxicity values are expected to be in the range of 1 - 10 mg/l based upon data

from components and similar products. This material may be harmful to aquatic organisms and

may cause long term adverse effects in the aquatic environment. The log Kow value for this

product is 3.66.

10.1.10 DISPOSAL CONSIDERATIONS

Hazard characteristic and regulatory waste stream classification can change with product use.

Accordingly, it is the responsibility of the user to determine the proper storage, transportation,

treatment and/or disposal methodologies for spent materials and residues at the time of

disposition. If discarded, Cumene is regulated by US EPA as a listed hazardous waste (U055).

Transportation, treatment, storage and disposal of waste material must be conducted in

accordance with RCRA regulations (see 40 CFR 260 through 40 CFR 271). State and/or local



regulations may be more restrictive. Contact the RCRA/Superfund Hotline at (800) 424-9346 or

your regional US EPA office for guidance concerning case specific disposal issues.



Chapter 11

PLANT LOCATION AND LAYOUT

Plant location and site selection:

The location of the plant can have a crucial effect on the profitability of a project and the scope

for future expansion. Many factors must be considered when selecting a suitable site. The factors

to be considered are:

1. Location with respect to the marketing area

2. Raw material supply.

3. Transport facilities.

4. Availability of labour.

5. Availability of utilities: water,fuel,power.

6. Availability of suitable land.

7. Environmental impact, and effluent disposal.

8. Local community considerations.

9. Climate.

10. Political and strategic considerations.

Marketing Area:

For materials that are produced in bulk quantities such as cement, mineral acids and fertilizers

where the cost of the product per ton is relatively low and the cost of transport a significant

fraction of the sales price, the plant should be located close to the primary market. This

consideration will be less important for low volume production, high-priced products, such as

pharmaceuticals.

Raw Materials:

The availability and price of suitable raw materials will often determine the plant location. Plant

producing bulk chemicals are best located close to the source of the major raw material: where

this is also close to the marketing area.

Transport:

The transport of materials & products to & from the plant will be an overriding consideration in

site selection. If practicable, site should be selected that is close to at least two major forms of

transport road, rail, waterway (canal or river) or a sea port. Road transport is being increasingly

used, and is suitable for long-distance transport of bulk chemicals. Air transport is convenient &



efficient for the movement of personnel &essential equipment & supplies & the proximity of the

site airport should be considered.

Availibility of labour:

Labour will be needed for construction of the plant & its operation. Skilled construction workers

will usually be brought in from outside the site area, but there should be an adequate pool of

unskilled labour available locally ; & labour suitable for training to operate the plant. Skilled

tradesmen will be needed for plant maintenance. Local trade union customs & restrictive

practices will have to be considered when assessing the availability & suitability of the local

labour for recruitment & training.

Utilities(Services)

Chemical processes invariably require large quantities of water for cooling & general process use

, & the plant must be located near a source of water of suitable quantity. Process water may be

drawn from a river, from wells, or purchased from a local authority. At some sites the cooling

water required can be taken from a river or lake , or from the sea; at other locations cooling

tower will be needed. Electrical power will be needed at all sites. Electrochemical processes that

require large quantities of power; for example, aluminium smelters need to be located close to a

cheap source of power. A competitive priced fuel must be available on site for steam & power

generation.

Environment impact,& disposal:

All industrial processes produce waste products & full consideration must be given to the

difficulties & cost of their disposal. The disposal of toxic & harmful effluents will be coverd by

local regulations & the appropriate authorities must be consulted during the initial site survey to

determine the standards that must be met. An environmental impact assessment should be made

for each new project or major modification or addition to an existing process.

Local community considerations:

The proposed plant must fit in with & be acceptable to the local community. Full consideration

must be given to the safe location of the plant so that it does not impose a significant additional

risk to the community. On a new site, the local community must be able to provide adequate

facilities for the plant personnel: school, banks, housing & recreational & cultural facilities.



Land (site selection)

Sufficient suitable land must be available for the proposed plant & for future expansion. The land

should ideally be flat, well drained & have suitable load bearing characteristics. A full site

evaluation should be made to determine the need of piling or other special formations.

Climate:

Adverse climate conditions at a site will increase cost. Abnormally low temperatures will require

the provisition of additional insulation & special heating for equipment & pipe runs. Stronger

structures will be needed at locations subject to high winds (cyclone hurricane areas) or

earthquakes.

Political & Stratergic Considerations:

Capital grants tax concessions & other inducements are often given by the government to direct

renew investments to preferred locations, such as areas of high unemployment. The availability

of such grants can be the overriding consideration in site selection.

Site Layout:

The process units & ancillary buildings should be laid out to give the most economical

Flow of materials & personnel around the site. Hazardous processes must be located at a safe

distance from other buildings. Consideration must also be given to the future expansion of the

site. The ancillary buildings & services required on a site, in addition to the main processing

units will include.

1. Storages for raw materials & products: tank farms & warehouses.

2. Maintenance workshops.

3. Stores for maintenance & operating supplies.

4. Laboratories for process control

5. Fire stations & other emergency services.

6. Utilities: steam boilers, compressed air, power generation , refrigeration, transformer stations.

7. Effluent disposal plant .

8. Offices for general administration.

9. Canteens & other amenity buildings, such as medical centers.

10. Car parks

When roughing out the preliminary site layout, the process units will normally be sited first &

arranged to give a smooth flow of materials through the various processing steps, from raw



material to final product storage. Process units are normally spaced at least 30m apart; greater

spacing may be needed for hazardous processes. The location of the principal ancillary buildings

should then be decided. They should be arranged so as to minimize the time spent by personnel

in travelling between buildings. Administration offices & laboratories, in which a relatively large

number of people will be working, should be located well away from potentially hazardous

processes. Control rooms will normally be located be located adjacent to the processing units,

but with potentially hazardous processes may have to be sited at a safer distance. The sitting of

the main process units will determine the layout of the plant roads, pipe alleys & drains. Access

roads will be needed to each building for construction & for operation & maintenance. Utility

buildings should be sited to give the most economical run of pipes to & from the process units.

Cooling towers should be sited so that under the prevailing wind the plume of condensate spray

drifts away from the plant area & adjacent properties. The main storage area should be placed

between the loading & unloading facilities & the process units they serve. Storage tanks

containing hazardous materials should be sited at least 70m from the site boundary.

Plant Layout:

The economic construction & efficient operation of a process unit will depend on how well he

plant & equipment specified on the process flow-sheet is laid out. The principal factors to be

considered are:

1. Economic consideration: construction & operating cost

2. The process requirements

3. Convenience of operation

4. Convenience of maintenance

5. Safety

6. Future expansion

7. Modular construction

Costs:

The cost of construction can be minimised by adopting a layout that gives the shortest run of

connecting pipe between equipment & the least amount of structural steel work. However this

will not necessarily be the best arrangement for operation & maintainance.



Process Requirements:

An example of the need to take into account process considerations is the need to clevate the

base of columns to provide the necessary net positive suction head to a pump or the operating

head for a thermosyphon reboiler.

Operator:

Equipment that needs to have frequent operator attention should be located convenient to the

control room. Valves,sample points, and instruments should be located at convienient positions

and heights.Sufficient working space and head room must be provided to allow easy access to

equipments.

Maintainance:

Heat exchangers need to be cited so that the tube bundles can be easily withdrawn for cleaning

and tube replacement. Vessels that require frequent replacement of catalyst or packing should be

located on the outside of buildings. Equipment that requires dismantling for maintainnace, such

as compressors and large pumps, should be placed under cover.

Safety:

Blast walls maybe needed to isolate potentially hazardous equipment, and confine the effects of

an explosion. At least two escape routes for operators must be provided from each level in the

process buildings.

Plant Expansion:

Equipments should be located so that it can be conveniently tied in with any future expansion of

the process. Space should be left on pipe alleys for future needs, and services pipes over-sized to

allow for future requirements.

Modular Constructions:

In resent years there has been a move to assemble sections of plant at the plant manufacturers

site. These modules will include the equipment, structural steel, piping and instrumentation. The

modules are then transported to the plant site, by road or sea. The advantage of modular

construction are :

(1) Improved quality control

(2) Reduced construction cost

(3) Less need for skilled labour on site.

(4) Less need for a skilled personal on overseas sites.



Some of the disadvantages are:

(1) Higher design costs.

(2) More structural steel work.

(3) More flanged connections.

(4) Possible problems with assembly on site.

Utilities:

The word utilities is not generally used for the ancillary services needed in the operation of any

production process. These services will normally be supplied from a central site facility, and will

include:

(1) Electricity.

(2) Steam for process heating.

(3) Cooling water.

(4) Water for general use.

(5) Demineralised water.

(6) Compressed air.

(7) Inert gas supplies.

(8) Refrigeration.

(9) Effluent disposal facilities.

Electricity:

.The power required for electrochemical processes, motor drives, lighting, and general use

maybe generated on site, but will more usually be purchased from the local supply company. The

voltage at which the supply is taken or generated will depend on the demand. For a large site the

supply will be taken at a very high voltage, typically 11,000 or 33,000 V. Transformers will be

used to step down the supply voltage to the voltages used on the site. In the United Kingdom a

three phase 415V system is used for general industrial purposes, and 240V single phase for

lighting and other low power requirements. If a number of large motors is used, a supply at an

intermediate high voltage will also be provided, typically 6000 or 11,000V

Steam:

The steam for heating is usually generated in water tube boilers using the most economical fuel

level available. The process temperatures required can usually be obtained with low temperature

steam typically 2.5 bar and steam distributed at a relatively low pressure, typically around 8 bar



(100 psig). Higher steam pressures, or proprietary heat transfer fluids, such as dowtherm will be

needed for high process temperatures.

Combined Heat and Power (Co-generation):

The energy costs on a large site can be reduced if the electrical power required is generated on

the site and the exhaust steam from the turbines used for process heating. The overall thermal

efficiency of such systems can be in the range 70-80 %, compared with the 30-40 % obtained

from a conventional power station, where the heat in the exhaust steam is wasted in the

condenser. Whether a combined heat and power system scheme is worth considering for a

particular site will depend on the size of the site, the cost of fuel, the balance between the power

and heating demands, and particularly on the availability of and cost of, stand by supplies and the

price paid for any surplus power electricity generated.

Cooling Water:

Natural and forced draft cooling towers are generally used to provide the cooling water required

in a site; unless water can be drawn from a convinient river or lake in sufficient quantity.

Water for General Use:

The water required for general purposes on a site will usually be taken from the local mains

supply, unless a cheaper source of suitable quantity water is available from a river, lake or well.

Demineralised Water:

Demineralised water from which all the minerals have been removed by ion exchange, is used

where pure water is needed for process use, and as boiler feed water. Mixed and multiple bed ion

exchange units are used, one resin converting the cations to hydrogen and the other removing the

acid radicals. Water with less than one ppm of dissolved solids can be produced.

Refrigeration:

It will be needed for processes that require temperatures below those that can be economically

obtained with cooling water. For temperatures down to around 10 o C chilled water can be used.

For lower temperatures, down to -30oC, salt brines are used to distribute the “refrigeration”

round the site from a central refrigeration machine.

Compressed Air:

It will be needed for general use, and for the pneumatic controllers that are usually used for

chemical process plant control.



Inert Gases:

Where large quantities of inert gas are required for the inert blanketing of tanks and for purging

is usually supplied from a central facility. Nitrogen is normally used and is manufactured on site

in an air liquefaction plant, or purchased as liquid in tankers.

Effluent Disposal:

Facilities will be required at all sites for the disposal of waste materials without creating a public

nuisance.

SITE LAYOUT



Admin.

Building

R & D centre

Canteen

Parking

Area

Security

Office

Main Control

Room

Plant

Utilities

Product Dispatch

Section

Medical

Centre

Green Belt

Space for future

expansion

Main unit

Workshop

Power Station

E.T.P.

Tank Farm

Gate 1

Gate 2

Wind



Chapter 13

REFERENCE

1. Navid Naderpour , “Petrochemical Production Process” – SBS Publisher εt

Distributors Pvt.Ltd.

2. “Petroleum Technology” - Wiley Critical Content, Vol.-2, pp

3. Sun G Gyu Lee, “Encyclopedia of Chemical Processing”- Taylor & Francis

Publisher,Vol.-1

4. PERRY & CHILTON, “ Chemical Engineers Handbook”

5. Austin,G.T.”Shreve’s Chemical Process Industries”5th Ed.,McGraw Hill International

Edition.

6. Dryden’s outline of chemical technology for 21st Century.

7. Kirk Othmer Encyclopedia Of Chemical Technology(2005), Fifth edition, Volume

10.

8. Ullmman’s Encyclopedia Of Industrial Chemistry(1985), Volume 12.

9. Y.V.C.Rao, Chemical Engineering Thermodynamics(2005), Universities Press(India)

Private Limited.

10. B I Bhatt, S M Vora, Stoichiometry, 4th

Ed., McGraw Hill, USA, 2005.

11. Himmelblau D. V., Basic principles and calculations in chemical engineering, 5

th Ed.,

Prentice-Hall, USA, 1989.

12. 639120 - Brayford, D.J., “Cumene,” in Encyclopedia of Chemical Processing and

Design, 14 (1982), 33-52

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