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Acetone Production Report

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SUMMARY

The process purpose is to produce acetone from isopropyl alcohol (IPA) at the given conditions. This report is formed, some properties, manufacturing process of acetone. In manufacturing process, feed drum, vaporizer, heater, reactor, furnace, cooler, condenser, flash unit, scrubber, acetone and IPA columns are used.

This profile envisages the establishment of a plant for the production of acetone with a capacity of 100 tons per annum.

The present demand for the proposed product is estimated at 70 tons per annum. The demand is expected to reach at 137.7 tones by the year 2017.

The plant will create employment opportunities for 20 persons.

The total investment requirement is estimated at Birr 6.17 million, out of which Birr 2.84 million is required for plant and machinery.

The project is financially viable with an internal rate of return (IRR) of 14 % and a net present value (NPV) of Birr 1.71 million, discounted at 8.5%.

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NOMENCLATURE

MW=Molecular Weight [kg/kmol] N = mole [mol/h]

Y = mol or mass fraction of gas stream X = mol or mass fraction of liquid stream P Tn = Total Pressure [bar]

Pi*n= Vapour Pressure of Component [bar] Pv* = Vapour Pressure [bar]

F = Feed Flow Rate [k mol/h] V = Flow Rate of Vapour [kmol/h] L = Flow Rate of Liquid [kmol/h] T = Temperature [° C]

∆ Hvap = Latent Heat of Vaporization [kJ/kg] TC = Critical Temperature [° C]

PC = Critical Pressure [bar] Tb = Normal Boiling Point [° C] Q = Heat [kJ]

M = Mass Flow Rate [kg/h] K = Activity Coefficient

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Introduction:-

Acetone is the organic compound with the formula (CH3)2CO, a colorless, mobile, flammable

liquid, the simplest example of the ketones. Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory. About 6.7 million tons were produced worldwide in 2010, mainly for use as a solvent and production of methyl methacrylate and bisphenol A. Familiar household uses of acetone are as the active ingredient in nail polish remover and as paint thinner. It is a common building block in organic chemistry.

Acetone is naturally produced and disposed of in the human body as a result of normal metabolic processes. It is normally present in blood and urine. Diabetic people produce it in larger amounts. Reproductive toxicity tests show that it has low potential to cause reproductive problems. In fact, the body naturally increases the level of acetone in pregnant women, nursing mothers and children because their higher energy requirements lead to higher levels of acetone production. Ketogenic diets that increase acetone in the body are used to reduce epileptic attacks in infants and children who suffer from recalcitrant refractory epilepsy. Acetone (dimethyl ketone, 2-propane, CH3COCH3) formulation weight 58,079 is the simplest and the most important of the ketones. It is a colorless, mobile, flammable liquid with a mildly pungent and somewhat aromatic odour. It is miscible in all proportions with water and with organic solvents such as ether, methanol, ethyl alcohol, and esters.

Acetone is used as a solvent for cellulose acetate and nitrocellulose, as a carrier for acetylene And as a raw material for the chemical synthesis of a wide range of products such as ketene, Methyl methacrylate, bisphenol A, diacetone alcohol mesityl oxide, methyl isobutyl ketone, Hexylene glycol (2-methyl-2, 4-pentanediol), and isophorone.

Acetone is produced in various ways;

1. The Cumene Hydro peroxide Process for Phenol and Acetone 2. Isopropyl Alcohol Dehydrogenation

3. Direct Oxidation of Hydrocarbons to a Number of Oxygenated Products Including Acetone

4. Catalytic Oxidation of Isopropyl Alcohol

5. Acetone as a By-Product of the Propylene Oxide Process Used by Oxirane 6. The p-Cymene Hydro peroxide Process for p Cresol and Acetone

7. The Diisopropylbenzene Process for Hydroquinone (or Resorcinol) and Acetone In this report isopropyl alcohol dehydrogenation was investigated.

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PHYSICAL AND CHEMICAL PROPERTIES:

Appearance: - Liquid. Clear. Molecular wt.:- 58.079

Colour: - Colourless.

Density/specific gravity (g/ml):- 0.79 Temperature (°C): 20 Melting Point -94.60C

Boiling Point 56.130C (at 760 mm Hg)

Vapour Pressure: - 24 .7 KP at Temperature (°C): 20Evaporation Rate: - .6

Volatile by vol. (%):- 10

Solubility description: - Miscible with water. Solubility Value (g/100g H 2O20°C ):- 100

Auto Ignition Temp. (°C):- 540 Flammability limit (lower) (%):- 2.1 Flammability limit (upper) (%):- 13.0

Stability and Reactivity:

Stability: - Stable under normal conditions of use.

Conditions to avoid: - Avoid contact with: Strong oxidising agents. Avoid

Contact with acids. Avoid heat, flames and other . . Sources of ignition

Materials to avoid: - Potassium sulphate, sodium hydroxide, sulphuric acid,

Nitric acid, hydrogen peroxide, chloroform, activated Carbon, Bromine.

Hazardous Decomp.Product - Thermal decomposition or burning may release oxides

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Uses-:

About a third of the world's acetone is used as a solvent, and a quarter is consumed as a precursor to methyl methacrylate.

Solvent use:

Acetone is a good solvent for most plastics and synthetic fibers including those used in laboratory bottles made of polystyrene, polycarbonate and some types of polypropylene. It is ideal for thinning fibreglass resin, cleaning fiberglass tools and dissolving two-part epoxies and superglue before hardening. It is used as a volatile component of some paints and varnishes. As a heavy-duty degreaser, it is useful in the preparation of metal prior to painting; it also thins polyester resins, vinyl and adhesives. It is also useful for high reliability soldering applications to remove solder rosin after soldering is complete. This helps to prevent the Rusty bolt effect from occurring due to dirty solder contacts.

Storage of acetylene

Although flammable itself, acetone is also used extensively as a solvent for the safe transporting and storing of acetylene, which cannot be safely pressurized as a pure compound. Vessels containing a porous material are first filled with acetone followed by acetylene, which dissolves into the acetone. One litter of acetone can dissolve around 250 litters of acetylene.

Methyl methacrylate

This application begins with the initial conversion of acetone to acetone cyanohydrins: (CH3)2CO + HCN → (CH3)2C (OH) CN

In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified: (CH3)2C (OH) CN + CH3OH → CH2= (CH3) CCO2CH3 + NH3

The third major use of acetone (about 20%) entails its condensation with phenol to give bisphenol A

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Bisphenol A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins.

Medical and cosmetic uses

Acetone is used in a variety of general medical and cosmetic applications and is also listed as a component in food additives and food packaging.

Acetone is commonly used in chemical peeling. Common agents used today for chemical peels are salicylic acid, glycolic acid, 30% salicylic acid in ethanol, and trichloroacetic acid (TCA). Prior to chemexfoliation, the skin should be cleaned properly and excess fat removed. This process is known as defatting. Acetone, Septisol, or a combination of these agents is commonly used in this process.

Laboratory uses

In the laboratory, acetone is used as a polar aprotic solvent in a variety of organic reactions, such as SN2 reactions. The use of acetone solvent is also critical for the Jones oxidation. It is a

common solvent for rinsing laboratory glassware because of its low cost and volatility. H\however, it does not form an azeotrope with water (see azeotrope (data)). Despite its common use as a supposed drying agent, it is not effective except by bulk displacement and dilution. Acetone can be cooled with dry ice to −78 °C without freezing; acetone/dry ice baths are commonly used to conduct reactions at low temperatures. Acetone is fluorescent under ultraviolet light, and its vapour may be used as a fluorescent tracer in fluid flow experiments.

Domestic and other niche uses

Acetone is often the primary component in cleaning agents such as nail polish remover. Ethyl acetate, another organic solvent, is sometimes used as well. Acetone is a component of superglue remover and it easily removes residues from glass and porcelain.

It can be used as an artistic agent; when rubbed on the back of a laser print or photocopy placed face-down on another surface and burnished firmly, the toner of the image transfers to the destination surface. Make-up artists use acetone to remove skin adhesive from the netting of wigs and moustaches by immersing the item in an acetone bath, then removing the oftened glue residue with a stiff brush.

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MARKET TREND -:

Past Supply and Present Demand

The country's requirement for acetone is totally met through import. Data obtained from the Ethiopian Customs Authority with regard to import of acetone for the period covering 1997 - 2011 is given in Table-

IMPORTANCE OF ACETONE YEAR QUANTITY(Mt.Tons)

1997 41.6 1998 90.6 1999 52.7 2000 24.7 2001 154.3 2002 34.0 2003 34.3 2004 57.7 2005 47.5 2006 84.2 2007 70.5 2008 74.9 2009 80.2 2010 85.8 2011 91.8

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Projected Demand -: Acetone is used as a solvent in the production of paint, varnish,

lacquer, cellulose acetate, potassium iodide and permanganate. It is also used to clean dry parts of precision equipments, delusterant for cellulose acetate fibre and specification testing of vulcanized rubber products. This clearly indicates that demand for acetone is directly related with the development of the industrial sector. Taking this in consideration, annual average growth of 7% is applied to forecast the future demand. The forecasted demand up to the year 2017 is given in Table 3.2. 55-6 import figures were much higher than the imports in the following years. In 1998, the import figure was about 90.6 tonnes while in the following years, i.e., 1999 and 2000 the import figure dropped to 52.7 tonnes and 24.7 tonnes respectively. Similarly, import figure in the year 2001 was about 154 tones while in the following four consecutive years, i.e., from 2002 - 2005 import ranges from only 34 tonnes to about 58 tonnes. This probably indicates that the high imports in some years were used as buffer stocks for the following years. Hence, some portions of the imports were distributed among the subsequent years in which recorded import figures were found to be comparatively low.

By looking to the above argument, the present effective demand is estimated using the following methodology.

The average import figures in the recent past six years, i.e., 2001- 2006 is taken as an effective demand for the year 2007 since the product is directly related with the growth of the manufacturing sector, an annual average growth rate of 7% (which is recorded by the industrial sector in the past) is applied to arrive at the current (year 2007) demand.

PROJECT DEMAND OF ACETONE YEAR QUANTITY(Mt.Tons)

2012 98.2 2013 105.1 2014 112.4 2015 120.3 2016 128.7 2017 137.7

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METHODS OF PRODUCTION:-

(a) Catalytic Dehydrogenation of Isopropanol (b) Oxidation of Isopropyl benzene

(c) Co product of Glycerine- H2O2 process

(d) Oxidation of Butanol (e) Oxidation of Propylene

(a) Acetone by oxidation of Propylene: A process for acetone production by direct

oxidation of propylene using air. In this process the catalysis consists of a solution of copper chloride containing small quantities of palladium chloride.

The overall reaction is as follows C3H6+1/2O2 CH3COCH3

(b) Oxidation of Butanol:

Catalytic oxidation of n butane using either cobalt or manganese acetate produces acetic acid at 75-80% yield. By products of commercial value are obtained in variable amounts. In the Celanese process the oxidation reaction is performed at a temperature range 150-2250C and pressure of approx 505 atm.

CH3CH2CH2CH3 + O2 CH3COOH + CH3COCH3

(c) Co product of Glycerine- H2O2 process:

When Glycerine is produced from propylene via acrolein then acetone is produced as a by product.

CH3CH═CH2 + H2O CH3CHOHCH3 + O2 CH3COCH3 + H2O2

(d) Oxidation of Isopropyl Benzene (Cumene):Cumene is synthesised from propylene

and benzene, followed by oxidation for the formation of hydro peroxide and splitting the same into acetone and phenol. The crude products are then fractionated to get pure acetone and phenol.

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(e) Dehydrogenation of Isopropanol: Acetone is produced from catalytic

dehydrogenation of isopropanol. The catalyst used in this process is ZNO.The crude product obtained from this process is fractioned and pure product is obtained.

(CH3)2CHOH (CH3)3CO + H2

The acetone produced in the reactor passes into a phase separator and then into a separation system that includes one stripping and two distillation columns. A recycle stream takes a mixture of unreacted isopropyl alcohol and water, with a trace amount of acetone, back into a mixer that feeds the reaction system. Using the catalyst which will be employed throughout this analysis, the reaction is first order with respect to the concentration of isopropanol and has an Arrhenius dependence on temperature with E=72.38 MJ/kmol and k=351,000 cubic m gas/cubic m reactor sec.

Reason for selecting the process: (Catalytic dehydrogenation of

Isopropanol):

Acetone production from Cumene process is a serious competitor for the isopropanol dehydrogenation process. Catalytic dehydrogenation of isopropanol can be chosen as a synthetic route when high-purity acetone is required, such as in biomedical applications. In this process 88% of isopropanol is recycled so this process is cost effective. Catalytic dehydrogenation of isopropanol gives approx 99% pure product.

Catalytic dehydrogenation of isopropanol: In the simplified process, an aqueous solution

of isopropyl alcohol is fed into the reactor, where the stream is vaporized and reacted over a solid catalyst at 2 atm. The reactions occurring within the reactor are as follows:

CH3-CHOH-CH3  CH3-CO-CH3 + H2

Isopropyl alcohol (IP) Acetone (AC) Hydrogen (HY)

CH3-CHOH-CH3 + ½ O2  CH3-CO-CH3 + H2O

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Flow Sheet of Acetone Production

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Process Description:

Feed drum is a kind of tank used for the mixing of the recycle stream and feed stream. Recycle stream concentration was assumed to be same with the feed stream. The temperature of the feed stream is assumed to be 250C at 2 bar pressure, which is assumed to be constant. The temperature of recycle stream was calculated as 111.50C. The temperature of the leaving stream was calculated as 32.890C, by the energy balance around feed drum. In the vaporizer molten salt was used for heating. The temperature at the entrance of the unit is the temperature of the mixture leaving the feed drum, which is 32.890C. And the leaving temperature is the bubble point temperature of the mixture, which is 109.50C. The pressure is 2 bars, and assumed to be constant. Since the temperature leaving the vaporizer is not enough for the reaction a pre-heat was used. The unit is working at 2 bars, and assumed to be constant. The entrance and leaving temperatures are 109.50 C and 3250 C. The reactor was the starting point for the calculations. The temperature values for the entering and leaving streams were found from literature, which are 3250C and 3500C, respectively. The reaction taken place inside is endothermic, for this reason the reactor has to be heated. For heating, molten salt was used. The pressure is 1.8 bar, and assumed to be constant. The entrance temperature of the cooler is 350 0C and leaving is 94.70C. For cooling, water was used. Instead of water a refrigerant may be used. Better results may get. But since it costs too much, it wasn‟t chosen as the cooling material. From the temperature values it‟s easily seen that the load is on the cooler not on the condenser, for this process. But in reality the unit cannot cool that much, and the load is mostly on the condenser. In this process, the mixture cooled down to its dew point. The pressure is 1,5 bar, and assumed to be constant.- 5 - The temperature of the entering stream is the dew point and the leaving temperature is the bubble point of the mixture. In the condenser water was used as cooling material. In the calculation of the dew and bubble points Antoine Equation was used. Trial and error was used with the help of Excel. The mixture includes acetone, i- propyl -alcohol, water and hydrogen. But hydrogen was not taken into consideration in the calculations. Since the condensation temperature of hydrogen is very low, it is not condense in the condenser. It stays in the for this reasons it has no affect on bubble and dew point calculations. Also since it does not affect the temperature calculations it‟s not taken into consideration on mole and mass fraction calculations. The leaving and entering temperatures are 94.70 0C and 81 0C, respectively. The pressure is 1.5 bar, and assumed to be constant. Flash unit was assumed to be isothermal, for this reason temperature was not changed. It is 81 0C in the entrance and exit. The pressure is 1.5 bar, and assumed to be constant. By trial and error method, (V / F) value was found to be

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0.2. The entrance temperature of the unit is the bubble point of the mixture, but if it was its dew point the (V/F) value would be much higher. Scrubber was assumed to be adiabatic. The temperature of water entering the unit was assumed to be 25 0C. The temperature of the off gas, including hydrogen and a very little amount of acetone, was assumed to 70 0C. But this assumption is too high, a lower temperature should have been assumed, since a lot of water is used in the unit. It should have been around 40 0C – 50 0C. The temperature of the leaving stream was found to be 28.1 0C.The pressure of the unit is 1.5 bar, and assumed to be constant

Raw Material

Propylene or ISO-propyl alcohol is the only raw material used for manufacturing of acetone in the presence of a catalyst. Packaging materials are required for delivering this product. The annual materials requirement and cost of the plant is given in Table 4.1.

ANNUAL CONSUMPTION OF RAW MATERIALS AND COST ANNUAL CONSUMPTION

OF RAW MATERIALS AND COST Description

Unit of meas.

Qty. Cost in '000 Birr

F.C L.C T.C

Propylene tonnes 120 918 162 1080

Catalyst (silver or copper) " 0.5 17 3 20

Water m3 80 - 0.26 0.26

Packaging Barrel 625 - 188 188

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7.2 MATERIAL BALANCE: 7.2.1 Material Balance on Reactor:

CONVERSION = 90%

Nacetron5= 100*0.9 =90kmole/hr

Nh25 =100*0.9 =90 kmole/hr

NH2o 5 =49.25kmole/hr

Nipa =100*0.1= 10 kmole/hr

Ntotal= naceton +nh2o + nh2 5 +nipa =239.25kmole/hr

Yacetone =90/239.25= 0.376

Yh2 5=90/239.25 =.376

YH2o= 49.25/239.25= o.206

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7.2.2 Material Balance on Flash Unit:

It is assume that there is no change at temp. and pressure.

Ki == pi*/pp= yi/xi (at bubble point = 810c)

For Acetone Logp*aceton =7.0947 – 1161/ (224+81) P*aceton= 1651.6mmHg Kaceton =1651.6/ ((1.5/1.013)*760) = 1.467 For IPA Log p*= 8.37895- 1788.02/ (227.438+81) P*ipa =381`.89 mmHg Kipa = 381.89/1125.092 =0.339 For H2O Log p*H2O = 7.96681 – 1668.21/ (228+81) P*H2O = 369.89

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KH2O = 369.89/1125.092 = 0.328

For Trail error

F/V = 0.2

Ft= nacetone +

n

H2O + nipa =149.25

F = V + L V/F =0.2 Solving V = 29.85kmole/hr , L= 119.4 Kmole/ hr YV = K * xl F*ZF = Vx *yv + z* xl For Acetone Yv = 1.467 * xL 90=29.85 yv + 119.4* xL After solving Xl=0.551 Yv = 0.809 For IPA Yv = 0.339 * xL 10= 29.85 * yv + 119.4 * xl After solving Xl ==0.077 Yv = 0.026 For water Yv = 0.328 *xl 49.25 = 29.85 * yv + 119.4 * xl X l = o.381 Yv = o.125

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At Stream 8: V= 29.85 kmol/hr. Yacetone= 0.809 Nacetone8= (0.809)*(29.85) = 24.148 kmol/hr Yipa= 0.026 Nipa8= 0.026*29.85= 0.766 kmol/hr YH2O =0.125 NH2O= (0.125)*(29.85) =3.731kmol/hr At Stream 9 L= 119.4kmol/hr

Xacetone=0.551 nacetone= (0.551)*(119.4) = 65.789 kmol/hr

Xipa=0.077 nipa9= (0.077)*(119.4) = 9.149 kmol/hr

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7.2.3 Material balance for Scrubber:

T=(81oC) = 354.15 K, P=1.5bar

Assume: 1/1000 of inlet acetone is off gas.

Nacetone12= 0.024148 kmol/hr

Nacetone10=24.148-0.024148=24.124kmol/hr

Ntotal= nacetone+nH2,8+nH2O+nipa 24.148+90+3.731+0.776 = 118.655 kmol/hr

nacetone12= nacetone12+nH2,12 0.024148+90 = 90.024kmol/hr

Yacetone=0.024148/90.024= 2.68*10-4

Yacetone8= 24.148/118.655 =0.203

Yacetone12/ Yacetone8=1-A/1-A6 Where A =L11/m* V8

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M= 1.445

Yacetone12/ Yacetone8=2.68*10-4/0.203 = 1.320*10-3= 1-A/1-A6

From trial error A is found is 3.523

L11= m*A*V8= 1.445*3.523*118.655 = 604.041 kmol/hr

NH2O10= nH2O8+ nH2O11 3.731+604.041 =607.772 kmol/hr

Ntotal10= nacetone10+nH2,10+nipa10 24.124+607.772+0.776= 632.6724 kmol/hr

7.2.4 Material balance for Acetone Column

Nacetone13= Nacetone9+nacetone10= 65.789+24.124= 89.913kmol/hr

Nipa13= Nipa9+ Nipa10= 9.194+0.776 = 9.97 kmol/hr

NH2o13= NH2o9+ NH2o10= 45.491+607.772=653.263 kmol/hr

Assume: 1/1000 of acetone is in bottom product.

Nacetone15=89.913/1000= 0.089kmol/hr

Nacetone14= 89.913-0.089= 89.824kmol/hr

Since acetone purity is 99%.

Nipa14=89.824*(0.01/.99)= 0.907kmol/hr

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NH2O15=nH2o13=653.263kmol/hr

7.2.5 Material Balance for IPA column:

All the ipa is at the top product

Nipa17 = nipa 15 = 9.063 kmole/hr

Nacetone17 = nacetone15 = 0.089kmole/hr

Assume the composition of the recycle stream is as feed stream so that Yacetone = 0.33 yipa =o.67

N H2O 17 = 9.063 * 0.33/o.67 = 4.469kmole/hr

nwater = nwater - nwater = 653.263 - 4.464 = 648.729kmole/hr

7.2.6 Material Balance for Feed Drum: INPUT = OUTPUT

Nipa 12 = nipa - nipa 17

= 100 - 9.063 = 90.933kmole/hr NH2O = nH2O + nh2o 17

NH2O = 49.25 - 4.464 = 44.786kmole/hr

Sience 115000tonns/day acetone is wanted to produce all of these calculation should be correlated as this amount, these new value are shown in lable

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= 45700.726 tpy

Scale factor

Sf = (115000ton/yr)/ 45700.726 = 2.516

7.3 ENERGY BALANCE 7.3.1 For Feed Drum

MH2O=2029.966kg/hr 1 T=250C Mipa=13749.785kg/hr 2 T=32.890C Mipa=15120.159kg/hr Mwater=2232.293kg/hr 3 Mipa=1370.369kg/hr Mwater=202.326kg/hr

Tref =250C Cp.pia=2497kj/kg Cp.water=4178kj/kg

For stream 1,2 and 17 calculate Cpmix

Cpmix = (2497*0.87)+(4178*0.13) =2715 kj/kg

Mtotal1=13749.785+2029.966= 15779.75 kg/hr

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Mtotal2=15120.154+2232.293=17352.447kg/hr Mtotal3=1370.369+202.326= 1572.695 kg/hr Qin=Qout 15779.75*2.715*(25-25) +1572.695*2.715*(111.5-25) = 17352.447*2.715*(T-25) T=32.830C 7.3.2 For Vaporiser: T=32.830C MIPA =15120.15kg/hr MH2O =2232.293kg/hr T =109.50C Mipa=15120.154 Kg/hr Mwater = 2232.293kg/hr At 32.83 0c Cpipa = 145kj/kmole K = 2.413 kj/kg K CpH2o = 4.179 kj/kg K For Water Tc = 508.3 K Tb = 394.399K ΔHf = 39838 kj/kmole

ΔHvap ,H2O = H [(Tc-T)/(Tc-Tb)]o.38

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= 2296.4731 kj/kg For IPA Tc = 647.3 K Tb = 375K ΔHf = 40683kj/kmole ΔH vap , ipa = 40683[(647.3k-382.5k)/(647.3k-375k)]0.38 =40253.505 kj/kmol = 66982kj/kg

Q = (mipa * Cpipa * Δ T) + ( mwater * Cpw * ΔT) + (mw *Δ H vep, wat) + (mpipa * ΔHvap ,ipa)

= 9.652 * 106 kj Molten Salt: We assume Δ T = 20 Q = m * Cpmolt.salt * Δ T 9.652*10^6 kj = 156 kj/kg * m * (20) M = 309.358 tons 7.3.3 Pre Heater: T=109.50C T=3250C Mwater=2232.253kg/hr Mwater=15120.154kg/hr Mipa=15120.154kg/hr Mipa=2232.293kg/hr

Tref=109.50C Cp,pia=24.6kj/kgk CpH2O=2019kj/kgk

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Q=(mwater*Cpwater*∆T)+(mipa*Cpipa*∆T)

=[(2232.293*2.468*(325-109.5)+(15120.154*2.019*215.5)] = 1.845*106 kj

Molten Salt: We assume ∆T= 1500

C

Q=m*Cp molten salt*∆T= 1.845*106=156*m*150

M=7.855 ton

7.3.4 For Reactor:

(CH3)2CHOH (CH3)2CO+ H2

COMPOUND Nin kmol/hr Hf kj/kmol Nout kmol/hr

(CH3)2CHOH 251.6 -272.290 25.16 CH3)2CO 0 -216.685 226.44 H2 0 0 226.44 T=3250C T=3500C MH2=435.144kg/hr Mipa =1512.015kg/hr Mipa=15120.154kg/hr Mwater=2232.293kg/hr Mwater= 2232.293kg/hr Macetone=13151.635kg/hr

Reactor

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∆Hin ipa= -272.29+25∫325(32.427+1.886*10-1T+6.405*10-5T2-9.261*10-8T5)dT

∆Hin ipa= -272.29+20.104 = -252186 kj/mol

∆Hout ipa= -27229+25∫350(32.427+1886*10-1T+6405*10-5T2-9261*10-8T3)dT

∆Hout ipa= -249.691 kj/kmol

∆Hout acetone= -216.685+25∫350(71.96+20.1*10-2T+12.78*10-5T2+3.476*10-8T3)dT

∆Hout acetone= -182.745 kj/mol

∆Hout H2= 25∫350(28.84*10-3+0.3288*10-8T2+0.00765*10-5T-0.8698*10-12T3)dT ∆Hout H2=9.466 kj/kmol ∆Hr0=(-216.685kj/kmol)-(-272.29)kj/kmol ∆Hr0= 55.605kj/kmol ∆Hr=226.44*55.685/1 =12591kj Q= ∑outniHi - ∑inniHi+∆Hr Q= [ 25.16( -249.691)+226.44(-182.745)+226.44(9.466)] – [252.6(-252.106)] +2591.196 Q=30521.67 kj Molten Salt Cp(molten salt b/w 3600C- 4100C) = 156kj/kg Q=m*Cp*∆T 30521.67=156*m*50 M=391.300kg/hr

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7.3.5 For Cooler T = 3500C MIPA = 1512.015kg/hr MH2O = 2232.293kg/hr T= 94.70c , Macetone = 13151.635kg/hr mipa =1512.015kg/hr MH2 = 455.144kg/hr mH2O =2232.293 kg/hr Macetone =13151.635 kg/hr MH2 = 455.144kg/hr Tref = 94.70c CpH2 = 12.608 kj/kg K CpH2O= 2.035 kj/kg K Cpipa =2.536kj/kg K Cpacetone = 1.096 kj/kg K We know

Q =[(mH2 *CpH2) + (mH2O * CpH2O) + (mipa * Cpipa) + (macetone * Cpacetone)] * del T

Q = - 10.123 * 106 kj

Water

Δ T water = 35- 20 =20

(28)

Q = m * CpH2o * Δ T 10.123 *106kg = 4.179kj/kg * m * 20 m = 121.117 ton/hr 7.3.6 For Condencer: T = 94.70C T = 81 0c MIPA =1512.O15Kg/hr MH2O =2232.293 kg/h mh2o= 2232.293kg/hr Macetone = 1315.635kg/hr macetone =13151.635kg/hr Mh2= 455.144 kg/hr mH2 = =455.444k/hr Log P* = a – b/(c+Tdp) Assumption = PT = 1.5 bar = 1125 mmHg

[(yacetone * pt )/(p*acetone * Tdp)] + [(yh2o * pt )/(p*water *Tdp)] + [(yipa * pt)/( pipa* * Tdp)] +

[(yH2 *pt)/(pH2* * Tdp)] = 1 From Literature : For acetone A = 7.02447 B = 1161 C = 224 For H2O A = 7.96681 B = 1668.21 C = 228 For IPA

(29)

A = 8.3789 B = 1788.02 C = 227.938 Using yaceton = 0.6 yH2o = 0.33 yipa = 0.07

By trial error Tdp = 94.7 0C For aceton At 14.70C & 1.5 bar Cpacetone = 1.297 kg /K Qacetone== m * Cp * del T = 13151.6322 * 1.297 [(81+273.15) - (943.7 +273.15)] = - 233.690 * 10-6 kj Δ Hvep = Δ Hf [(Tc - T)/(Tc-Tb)]0.38 = 29140 kj/kmole Tc 508.1 K Tb= 341.5 K Δ Hvap = =28289.029kj/kmole = 487.07 kj/ kg For IPA At 94.70c & 1.5 bar Cpipa = 1.761 kj / g KS Cpipa = 1.761 kj.kg K Qipa = =1512.015 * 1.761 *(354.15-367.85) = -36.487 * 10^-3 Kj ∆ H vep =delHf [(Tc -T)/(Tc –Tb)]0.38 ∆HF = 39850 kj/kmole Tc =508.3K Tb = 366.6K ∆Hvap = 4116935kg/kmole

(30)

∆Hvap = 685128 kj/kg For H2O At 94.7 oC & 1.50bar CpH2o = 1.898 kj/kgK QH2o = 2232.293 *1898 *(354.15 -367.85) = -58.045 *10^3 kj ∆Hvap = 40683 kj/kmole Tc = 647.3 K Tb = 385.106K ∆HVAP = 40683 * [(6473-354)/(6473-385.126)].38 = 42442.0561 kj/kmole =2356845 kj/lg For H2 At 94.70c & 1.5 bar CpH2 = 13.255 kj/kg K QH2 = 435.144 kg * 13225 * (354.15 – 367.85) = -82.464 * 103 kj ∑ m.Cp .∆ T = -410.677 *103 kg ∑mi ∆Hvap =12.702 * 106 kg QTOTAL = ∑mi CP,t ∆T + ∑mi . ∆Hvap = 12.3*10^6 For H2O ∆T for water = (35-15)= 20 Cpwater =40182 kj/lg

(31)

Q = m*Cpwater *∆ T 682691.799kj = 40182 kj/kg * m *20 m=147.038 ton/day ∆H vap == 40683 *[(647.3 -354)/(647.3 -385.186)]0.38 =2356.845 kj/kgmole 7.3.7 For Scrubber: Qin = Qout Tref = 250C 455.144 * 14.419 *(81-25)+ 3528.708 *1.259*(81- 25) + 169.107 * 4.193 *(81-25) + 117.307 * 1.716 *(81-25) = 455.144 *14.401 *(70-25) + 3.485 *1229*(70-25) + 35.25.224 * 1249 *(T-25) + 27547.709 *4.183 *(T -25) + 117.307 * 1710 * (T-25) 4222.8319 = 18777.661 + (T-25)*755114.9 T = 28.10C

7.3.8 For Acetone column:

∆ Hvap = ∆Hf[(Tc -T)/(Tc- Tb)]0.38

Befor the application the boiling temp (Tb) for each of the component must be find at 1.1 bar pressur.

For the boiling point calculation, ln psat = A - (B/T ) will be used

Condenser:

(32)

ln1.0133= A-B/329.2 ln47= A-B/508.1 then A=10.91 B= 3587.3

At 1.1 bar pressure boiling point is- ln1.1= 10.91-(3587.3/Tb)

Tb= 331.706K For ipa Pc=47.6 bar Tc=508.3K P= 1.0133 bar T= 355.35K ln1.0133= A-(B/355.35) ln47.6= A-(B/508.3) A=12.807 B= 4546.375 At 1.1 bar pressure boiling point is

ln1.1 = 12.807-(4546.375/ Tb) Tb= 357.653K

Substituting the result to the first equation:

∆Hacetone= 29140*[(508.1-375.3) / (508.1-331.706) ]0.38 = 26160195 kj/ kmol

∆Hipa= 39858*[(508.3-375.3) / (508.3-357.653) ]0.38

∆Hipa= 38014 kj/kmol

For the mixture:

∆Hmix= 450.417*0.99+632.618*0.01 = 452.24 kj/kg

MT=13263.045kg

For the energy balance of the mixture: Q= mT*∆Hmix= 6*106 kj

For Water:

Pc= 220.5 bar Tc= 647.3K P= 1.0133 bar T= 373.15K

(33)

ln220.5= A-(B/647.3) then A=12.72 B= 4743.39 At 1.1 bar pressure boiling point

ln1.1= 12.72-(4743.39/Tb) Tb=375.723K Reboiler: ∆Hvap, aceton =29140 *[(508.1-378)/(508.1-331.706)]0.38 =25956.795 kj/kmole =446.951 kj/kg FOR H2O ∆Hvap,H2O = 40683*[ (647.3-378)/(647.1-375.723)] 0.38

∆Hvap, H2O = 40533.043kj/kgmole = 474.872

∆Hvap, ipa = 39838 *[(508.3-378)/(508.3-337.653)]0.38

= 627.722 kj/kmole

Yacetone = 4.364 * 10-4 yH2O = 0.955 yipa =0.045

∆H vap,mix=446915 *6364 *10-4 + 674872 * 0.955 + 627.722*0.045 =672.945 kj/kg Balance; Q = mt . ∆ x vap mix = 30993.013*672.945 =20.86*106kj 7.3.9 IPA Column Tb ipa = 84.6530C TbH2o = 102.7230C

(34)

∆Hf,H2o =40683kj/kmole del Hf,ipa =39858kg/kmole

∆Hf,aceton = 29140 kj/kmole

∆Hvap,h2o =40294.194 kj/kmole= 2236.081kj/kg

∆Hvap,ipa = 38014 kj/kmole = 632.618kj/kg

∆Hvap,acetone = 26160.195 kj/kmole

sience aceton is neglected

YH2O = 0.13 Yipa = 0.87

∆Hvap,mix =2236.081*632.618

= 841.068 kj/kg

For the energy balance for mixing

Q = mT. ∆Hmix = 1941.326*841.068 =1.633 *106kj Reboiler: ΔHvap, water = 40683 * [(647.3-384.5)/(647.1-375.723)]0.38 =40179.523 kj/kmole =2230.892kj/kg Q = mT.ΔH.vap,water = 2230.892*29407.290 = 65.604 *106kj

(35)

Preliminary equipment summary table for acetone process

Equipment

P-401 A/B

P-402 A/B V-401

V-402

MOC

Carbon Steel Carbon

steel

Carbon

steel

Carbon

steel

POWER(Shaft)

(KW)

0.43

1.58

_

_

Efficiency

40%

50%

_

_

Type/Drive

Centrifugal/

Electric

Centifugal/

Electric

_

_

Op.Temreperatu

(

0

C)

32

360

32

20

Pressure In

(bar)

1.25

1.90

_

_

Pressure Out

(bar)

3.10

3.30

_

_

Diameter(m)

_

_

0.80

0.75

Height/Length

(m)

_

_

2.40

2.25

Orietionnt

_

_

Horizontal

Horizontal

Intenals

_

_

_

SS

Demister

Op. Pressure

(bar)

_

_

1.0

1.63

Maximum

Allowable

Op.Prs.(bar)

_

_

3.0

3.2

(36)

Preliminary equipment summary table for acetone process

(cont’d)

Equipment

T-401

H-401

R-401

MOC

Corban steel

Carbon steel

Carbon steel

Diameter

0.32

_

Width=4.57m

Height/Length(m)

3.20

_

Depth=6.10m

Height=5m

Orientation

vertical

_

Vertical

Internals

2.5m of packing

(1”Ceremic

Rashing Rings)

_

Fluidized bed

Containing 7.5m

3

of

catalyst+7.8m

3

of

inert particle

HTA=188m

2

Op. Pressure

(bar)

1.6

3.0

Tube side

2.16 in bed

2.70 in tube

Maximum

Allowable

Op.prs.(bar)

3.2

4.0

3.2 in bed

4.0 in bed

Type

_

Fired heat

_

Design

Duty(Mj/h)

_

3436

3436

Maximum Duty

(Mj/h)

_

3800

_

Area Radiant

(m

2

)

_

13.0

_

Area Convectiv

(m

2

)

_

37.0

_

(37)

Design Calculations

Vertical Tube Vaporizer

Conditions

Vapor leaves at 2.16 bar and 101C (saturated vapor). The shell side is assumed to be well mixed and at 101C.

Heat Transfer Calculations

1. Regulate steam pressure to give a 10C temperature driving force T sat = 111C which corresponds to a P sat = 1.48 bar.

2. Heat Duty = 2850 MJ/h , Cpl = 2880 J/kgºC

3. Limiting heat transfer resistance is on boiling organic side, shell = 1000 W/m2 shell C.

 Uh shell = 1000 W/m2C

(38)

A=Q/U•Tlm (F=1) = 285010 6 /3600/1000/10 = 79.2 m2

111

0

c

1010c T

32

0

c

Lenth along tubes

Note: over the range of ∆T = 7 to 250c it is known that hT 1/3 for boiling isopropanol.

(39)

Reactor

Heat Transfer Calculations

Assume that the fluidized bed is well mixed, thus the feed gas immediately heats to the reactor temperature of 350C. The molten salt approach temperature is 10C and therefore the molten salt temperature leaving the reactor is 360C. The temperature vs. Q diagram is shown below: Tin 3600c 3500c 3500c 1010c Length of reactor Q=3436 MJ/h

Cp,gas = 1780 J/kgºC (inlet) and 2500 J/kgºC (outlet)

Use Hi TecTM molten salt with the following average physical properties: C p = 1.72 kJ/kg K,  = 1980 kg/m3,  = 2.1 cP,

Maximum operating temperature = 1000C

Use a T = 50C for the circulating salt  Tin = 410C Tlm= (410-360)/ln[(410-350)/(360-350)] = 27.9C

(40)

Energy balance on molten salt

Q=MCpT 3436106 = (M)(1720)(50)

M = 39,950 kg/h = 11.10 kg/s

Vol flow of salt = M/ = 11.10/1980=5.60510-3

m3 /s

Evaluation of U

Fluidized Bed to tube wall, ho = 200 W/m2C

[this will not change much with fluidization velocity in the range of 2 – 5 umf ]

Inside heat transfer coefficient [molten salt to wall], h i = ? Assume that the velocity in the tubes is 2 ft/s = 0.61 m/s

Use ½” diameter tube 18 BWG with inside diameter = 0.01021 m Re = (0.61)(0.01021)(1980)/(0.0021) =5872

Nu = 0.023Re 0.8 Pr 0.33 = (.023)(5872) 0.8 (17200.0021/0.606) 0.33 = 42.9

(actually Seider-Tate is only good for Re>10,000 - check this later) hi = Nu[k/d] = (42.9)(0.606)/(.01021) = 2546 W/m2C

Below 500C molten salt should not foul so h f = very large Overall heat transfer coefficient, U = [d0/(dihi) + 1/ho]-1 = [1.244/2546+1/200]-1 = 182 W/m2C

(41)

Check tube arrangement and molten salt velocity

External surface area of 20 ft tubes =•doL = (3.142)(0.0127)(20)(0.3048) = 0.243 m2

Number of tubes = (188)/(0.243) = 773

Use 110 parallel sets of 7 tubes piped in series

Cross sectional area (csa) for flow of molten salt = (110)(3.142)(0.01021)2/4 = 0.0090 m2 Velocity of molten salt in tubes = 5.60510-3

/0.0090 = 0.622 m/s

This gives Re = 5988 and Nu = 43.6 and hi = 2588 and U = 182 W/m 2C no change

For Re<10,000 we should use correlation from Walas [1]:

Nu0.012[Re 0.87 280]Pr 0.4 [1-(d/L)2/3]

This gives Nu = 41.1 and h = 2438, thus U = 181 W/m 2 C same as before.

Arrangement of tubes in Fluidized Bed

(42)

Height of Catalyst and Filler in Bed

Use a square tube pitch of 1.5 inches

Dimensions of tube bank are 1101.5/12 by 71.5/12 by 20 ft = 13.75 by 0.875 by 20 ft

Assume bed width and depth of 15 by 20 ft respectively

Volume of solids to just cover the tubes, assuming bottom row of tubes is 6” from distributor plate and 6” of solids above tube bank = Vsol

V sol = (15)(20)(1+0.875) – volume occupied by tubes

= 562.5 – (770)(20)(•)(0.5)2 /(4144) = 541.5 ft 2 = 15.3 m3

Calculate the amount of catalyst required for 90% conversion

For a first order, isothermal, irreversible reaction at constant pressure we have the following expression for the conversion of component A,XA :

Kτ = (1+

ԑ

A

)ln (1/1-X

A

)-

ԑ

A

X

A

From the kinetics expression, at a reactor temperature of 350C, we have:

k=k0exp[-Ea/RT] =3.51×105exp[72,380/ (8.314)(273+350)]

=0.2996m3gas/m3bulk catalyst

ԑA= (number of mole if completely reacted – number of moles initially)/ number of moles

initially

= (96.48-57.84)/(57.84)=0.668

Using above values and 90% conversion we get: Kτ = (1+0.668)ln (1/1-0.9)-(0.668)(0.9)=3.2395 τ =(3.2395)/(0.2996) =10.813 m3

(43)

V

catalyst =

υ

gas

τ

Now the volumetric flow rate of gas, υgas =0.696 m3/s

Vcatalyst = (0.696)(10.83) =7.5 m3bulk catalyst

Amount of catalyst required is 7.5 m3, therefore we must add 7.8 m3 of inert filter to give a total of 15.3 m3 of bed solids. This will give a slumped bed height approximately 6 above the top of the tube bank.

Check minimum fluidizing velocity

Cross sectional area (csa) of bed = 300 ft2 = 27.9 m2 Properties of gas flowing through fluidized bed: = 1.067 kg/m3, = 18.210-6

kg/m.s flow of gas = 2670 kg/h

vol flow of gas = (2670)/[(1.067)(3600)] = 0.696 m3 /s Superficial gas velocity, u = (0.696)/(27.9) = 0.0250 m/s

catalyst particles are approximately 100 •m in diameter, and have a density of 2500 kg/m3

and bulk density of 1200 kg/m3 . Calculate minimum fluidizing velocity using the correlation due to Wen and Yu [2]

Repmf = [33.72 + 0.0408Ar]1/2-33.7 where Ar = dp3ρg(ρs-ρg)g/µ2

Ar = (10-4 )3 (1.067)(2500 – 1.067)(9.81)/(18.210-6 ) 2 = 78.97 Re pmf = [33.72 +0.0408(78.97)] 1/2– 33.7 = 0.0478

umf = (0.0478)(18.210-6 )/[(1.067)(10-4)] = 0.00815 m/s

u/u mf = 0.0250/0.00815 = 3.06  O.K.

(44)

Pressure Drop Across Fluidized Bed

Height of solids in fluidized bed = 1.875 ft = 0.57 m

Pbed = =hbulkg = (0.57)(1200)(9.81) = 6727 Pa = 0.067 bar

Distributor loss = 0.6 Pbed = 0.040 bar

Internal cyclone losses = 0.14 bar

(The design of the cyclones has been based on a maximum superficial gas velocity of 5umf )

Total loss across bed = 0.067 + 0.040 + 0.14 0.25 bar

Use a reactor height of 5.0 m to accommodate solids bed, plenum, freeboard, and cyclones.

Pressure Drop of Molten Salt through Heat Transfer Tubes

Re for molten salt flow = 5988

Roughness of drawn tubes, e = 0.0015 mm e/d = 0.0015/10.21 = 0.00015

f = 0.0087 d = 0.01021 m  = 1980 kg/m3

Leq = length of tube + equivalent length of 12-90 bends = (7)(20)(.3048) + (12)(30d)

= 46.3m

(45)

UTILITIES

Utilities required for manufacturing acetone include electric power, potable and cooling water, and steam.

Electricity

The power required for electrochemical processes; motor drives, lighting, and general use, may be generated on site, but will more usually be purchased from the local supply company (the national grid system in the UK). The economics of power generation on site are discussed by Caudle (1975). 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 415-V system is used for general industrial purposes, and 240-V 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 11,000 V.

A detailed account of the factors to be considered when designing electrical distribution systems for chemical process plants, and the equipment used (transformers, switch gearand cables), is given by Silverman (1964).

Water:

Cooling water

Natural and forced-draft cooling towers are generally used to provide the cooling water required on a site; unless water can be drawn from a convenient river or lake in sufficient quantity. Sea water, or brackish water, can be used at coastal sites, but if used directly will necessitate the use of more expensive materials of construction for heat exchangers

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 quality water is available from a river, lake or well.

(46)

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 1 part per million of dissolved solids can be produced.

ANNUAL CONSUMPTION OF UTILITIES AND COST

Description Unit of

Measure

Qty. Cost in '000 Birr

Electricity kWh 33,100 16

Furnace oil m3 140 757

Water m3 15,040 83

Total 856

Control and instrumentation

Instrumentation is provided to monitor the key process variables during the plant operations. They may be incorporated in automatic control loops, or used for the manual monitoring of the process operation. They may also be part of an automatic computer data logging system. Instruments monitoring critical process variables will be fitted automatic alarms to alert the operations to critical and hazardous situation.

It is desirable that the process variable to be monitored be measured directly ; often however, this is impractical and some dependent variables, i.e. easier to measure, is monitored in its place for example, in the control of the distillation columns the continuous , online analysis of the overhead product is desirable but difficult and expensive to achieve reliably, so temperature is often monitored as an indication of composition . The temperature instrument may form a part of a control loop controlling, say reflux flow; with the composition of the overhead checked frequently by sampling and laboratory analysis.

(47)

Instrumentation and Control Objectives

The primary objectives of the designer when specifying instrumentation and control objectives are;

1. Safe Plant Operation:

 To keep the process variables within known safe operating limits.

 To detect dangerous situations as they develop and to provide alarms and automatic shutdown systems.

 To provide interlocks and alarms to prevent dangerous operating procedures.

2. Production Rate:

To achieve the design product output.

3. Product Qualities:

To maintain the product composition within the specified quality standards.

4. Costs:

To operate at the lowest production cost, commensurate with the other objectives. These are not separate objectives and must be considered together.

The order in which they are listed is not mean to employ the precedence of any objective over another, other than that of putting safety first.

Product quality, production rate and the cost of production will be dependent on sale requirement. For example, it may be better strategy to produce a better quality product at a higher cost in a typical chemical processing plant these objectives are achieved by a combination of automatic control , manual monitoring and laboratory analysis .

Automatic Control System:

The detail design and specification of the automatic control schemes for a large product is usually done by specialists.

Guide Rule:

(48)

1. Identify and draw in those control loops that are obviously needed for steady state plant operation such as:

 Level control  Flow control  Pressure control  Temperature control

2. Identify the key process variables that need to be controlled to be achieved the specified product quality. Include control loops using direct measurement of the controlled variable, where possible; if not practicable, select a suitable dependent variable.

3. Identify and include those additional control loops required for safe operation.

4. Decide and show those ancillary instruments needed for the monitoring of the plant operation by operators; and for trouble shooting and plant development .It is well worthwhile including additional connection for instruments which may be needed for future trouble shooting and plant development, even if the instruments are not installed permanently. This would include: extra thermo wells, pressure tapings, orifice flanges, and extra sample points. 5. Decide on the location of the sample points.

6. Decide on the need for recorders and the location of the read out points, local or control rooms. This step would be done in conjunctions with step 1 to 4.

7. Decide on the alarms and interlocks needed; this would be done in conjunction with step 3.

9.3 Typical Control System: Level Control:

In any equipment where an interface exists between two phase (e.g. liquid –vapour), some means of maintaining the interface at required level must be provided. This may be incorporated in the design of the equipment. Figure shows a typical arrangement, as is usually done for the decanters by automatic control of the flow from the equipment.

(49)

Level control arrangement finds position at the base of column. The control valve should be placed on the discharge line from the pump.

Pressure Control:

Pressure control will be necessary for the most systems handling vapour of gas. The method of control will depend on the nature of the process. Typical schemes are proposed. When vented gas was toxic, or valuable. In these circumstances the vent should be taken to a vent recovery system, such as scrubber.

Flow Control:

Flow control is usually associated with inventory control in a storage tank or other equipment. There must be a reservoir to take up the charge ion flow rate.

To provide flow control on a compressor or pump running at a fixed speed and supplying a near constant column output ,a by pass control would we used.

Heat exchangers:

In the simplest arrangement, the temperature being controlled by varying the flow of the cooling and heating medium. If the exchange is between two process streams whose flow are fixed, by-pass control will have to be used.

Condenser Control:

Temperature control is unlikely to be effective for condensers, unless the liquid streams are sub cooled. Pressure control is often used or control an be based on the outlet coolant temperature.

Reboiler And Vaporizer:

As with condensers, temperature control is not effective as the saturated vapour temperature is constant at constant pressure. Level control is often used for vaporizers ; the controller controlling the stream supply to the heating surface , with the liquid feed to vaporizer on flow control. An increase in the feed results in an automatic increases in stream to the vaporizer the increased flow and maintains the level constant.

(50)

Cascade Control:

With this arrangement, the output of one controller is used to adjust the set point .cascade control can give smoother control in situation by direct control of the variable would lead to a unstable operation. The “Slave” controller can be used to compensate for any short –term variations in, say, a service. Stream flow, which would offset the controlled variable; the primary (master) controller long term variations.

Ratio Control:

Ratio control can be used for it is used where it is desired to maintain two flows at a constant ratio; for example, Reactor feeds and distillation column reflux.

Distillation Column Control:

The primary objective of distillation column control is to maintain the specified composition the top and bottom products, and any side streams; correcting for the effects of disturbances in:

. Feed flow rate, composition and temperature. . Stream supply pressure

. Cooling water pressure and heater temperatures.

. Ambient composition, which cause changes in internal reflux.

The compositions are controlled by regulating reflux flow and boil up. The column overall material balance must be controlled; distillation column has little surge capacity (hold up) and the flow of distillate and bottom product (and side streams). Must match the feed flows. A variety of control schemes has been devised for distillation column control. Column pressure is normally controlled at a constant value.

The feed flow –rate is often set by the level controller on a preceding column. it can be independently controlled if the column is fed from a storage or surge tank. feed temperature is not normally controlled, unless a feed preheated is used.

Temperature is often as an indication of composition. The temperature sensor should be located at the position in the column where the rate of change of temperature with change in composition of the key component is maximum. Near top and bottom of the column the change is usually small .with multicomponent systems, temperature is not unique function of the composition. Top temperature is usually controlled by varying the reflux ratio, the bottom temperature by varying the boil-up rate. If reliable on-line analyzers are variables they can be incorporated in the control loop, but more complex equipment will be needed.

Differential pressure control is often used on packed columns to ensure the packing operates at the correct loading.

(51)

Addition temperature indication or recording points should be included up the column for monitoring column performance and for troubleshooting.

Reactors Control:

The schemes used for reactor control depend on the process and the type of reactor. If reliable on-line analyzer is available, and the reactor dynamics are suitable, the product composition can be Monitored continuously and the reactor conditions and feed flows controlled automatically to maintain the desired product composition and yield.

Reactor temperature will normally be controlled by regulating the flow of heating or cooling medium. Pressure is usually held constant. Material balance control will be necessary to maintain the correct flow of reactants to the reactor and the flow of products and unreacted materials from reactor.

Alarms, Safety Trips and Interlocks

Alarm:

Alarms are used to alert operators of serious and potentially hazardous deviations in process conditions. Key instrument are filled with switches and relays to operate audible and visual alarms on the control panels and enunciators panels, where delay or lack of response, by the operator is likely to lead to the rapid development of a hazardous situations, the instrument would be fitted with a trip system to pumps, closing valves, operating emergency systems.

The basic components of the automatic control system are:

1. A sensor to monitor control variable and to provide an output signal when a preset value is exceeded.

2. A link to transfer the signal to the actuator, usually consisting of a system of pneumatic or electrical relays

(52)

Safety:

A safety trip can be incorporated in a control loop. In this system, high temperature alarm operates a solenoid valve, releasing the air on the pneumatic activator, closing the valve on high temperature. However the safe operation of such a system will be dependent on the reliability of the control equipment, and for potentially hazardous situation it is better practice to specify a separate trip system. Provision must be made for the periodic checking of the trip system to ensure that the system operates when needed.

Interlocks:

Where it is necessary to follow a fixed sequence of operations for example, during a plant start-up and shut-down , or in batch operations interlocks are included to prevent operators, departing from the required sequence. They may be incorporated in the control system design as the pneumatic or electric relays, or may be mechanical interlocks. Special locks with various properties and key system are available.

Computers and microprocessors an Process Control

Computers are being increasingly used for data logging, process monitoring and control. They have largely superseded the strip charts and analog controllers seen in the older plants. The long instrument panels and “mimic” flow charts displays have been replaced by intelligent video displays units. These provide a window on the process. Operators and technical supervisors can call up and display any section of the process to review the operating parameters and adjust control settings. Abnormal and alarm situation are highlighted and displayed.

Historical operating data is retained in the computer memory. Averages and trends can be displayed, for plant investigation and trouble shooting.

Software to continuously update and optimize plant performance can be incorporated in the computer control systems. Programmable logic controllers (PLC‟s) are used for the control and interlocking of the processes where a sequential operating steps has to be carried out, such as in the batch processes and in the start-up and shut-down of the continuous process.

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SAFETY DATA SHEET

ACETONE

1. IDENTIFICATION OF THE SUBSTANCE/PREPARATION AND THE COMPANY:

PRODUCT NAME: ACETONE

CHEMICAL NAME 2 : PROPAN-2-ONE 2 HAZARDS IDENTIFICATION:

Highly flammable. Irritating to eyes. Repeated exposure may cause skin dryness or Cracking. Vapours may cause drowsiness and dizziness.

3. FIRST AID MEASURES:

GENERAL: IN ALL CASES OF DOUBT OR WHEN SYMPTOMS PERSIST, ALWAYS

SEEK MEDICAL ATTENTION

IN HALATION: Move affected person to fresh air. If recovery not rapid, seek medical

attention. If breathing stops, provide artificial respiration. Keep affected person warm and at rest.

IN GESTION: Only when conscious, rinse mouth with plenty of water and give plenty of

water to drink - (approx 500ml). DO NOT INDUCE VOMITING. In case of spontaneous Vomiting, be sure that vomit can freely drain because of danger of suffocation. Keep patient at rest and obtain medical attention.

SKIN: Remove contaminated clothing. Wash affected area with plenty of soap and water.

Obtain medical attention.

EYES: Rinse immediately with plenty of water for at least 5 minutes while lifting the eye

lids.

Seek medical attention. Continue to rinse.

4. FIRE FIGHTING MEASURES:

EXTINGUISHING MEDIA: Water spray, fog or mist. Dry chemicals, sand, dolomite etc.

Halon. Powder, foam or CO2.

SPECIAL FIRE FIGHTING PROCEDURES:

Move container from fire area if it can be done without risk. Take measures to retain water used for extinguishing. Do not release contaminated water into drains, soil and surface water. Dispose of contaminated water and soil according to local regulations.

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UNUSUAL FIRE & EXPLOSION HAZARDS:

Forms explosive mixtures with air. Extremely flammable. May explode in a fire. Vapour may travel considerable distance to source of ignition and flash back.

HAZARDOUS COMBUSTION PRODUCTS:

Burning may release oxides of carbon and other hazardous gases or vapours.

PROTECTIVE MEASURES IN FIRE: Fire fighters should wear self-contained breathing

apparatus.

6. ACCIDENTAL RELEASE MEASURES:

PERSON AL PRECAUTION IN SPILL: Avoid direct contact with skin, eyes and clothing.

Do not breathe vapour or fumes.

PRECAUTIONS TO PROTECT ENVIRONMENT:

Prevent contamination of soil, drains and surface water.

SPILL CLEAN UP METHOD S: Accidental release measures - avoid ignition sources.

Take-up spillage with absorbent, inert material and place in a suitable and closable labelled container for recovery or disposal. Wash the area clean with water and detergent, observing environmental requirements. Absorb small quantities with paper towels or other inert material and allow to evaporate in safe place (fume hood/cupboard).

7. HANDLING AND STORAGE:

USAGE PRECAUTIONS: HANDLING - Product should be used in accordance with good

industrial principles for handling and storing of hazardous chemicals. Avoid vapour inhalation, skin and eye contact. Do not use contact lenses. Avoid vapour formation and ignition sources.

Ensure good ventilation and local exhaust extraction in work place. (engineering controls must be to explosion/flameproof standard). Earth container and transfer equipment to eliminate accumulation of static charge.

STORAGE PRECAUTIONS: Avoid direct sunlight. Store in a cool, dry, well ventilated

place, in securely closed original container.

STORAGE CRITERIA: Flammable liquid storage.

8. EXPOSURE CONTROLS AND PERSONAL PROTECTION: INGREDIENT NAME: CAS No.: STD LT EXP 8 Hrs ST EXP 15 Min

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INGREDIENT COMMENTS: Refer to the current edition of HSE Guidance Note EH

40/200* for occupational exposure limits;

VENTILATION: Work in fume cupboard. Respiratory protection required in insufficiently

ventilated woking areas.

RESPIRATORS: For short periods of work, a suitable RPE fitted with a combination

charcoal or organic vapour cartridge is recommended.

PROTECIVE GLOVES: Use impervious gloves made of butyl rubber of PTFE (teflon). EYE PROTECTION: Contact lenses should not be worn when working with this chemical!

Where the potential for eye contact exists, splash-proof goggles or face shield must be worn.

OTHER PROTECTION: Wear protective clothing and closed footwear. Wear personal

protective equipment appropriate to the quantity of material handled.

HYGIENIC WORK PRA CTIC ES: DO NOT SMOKE IN WORK AREA!

SKIN PROTECTION - use appropriate barrier cream to prevent defatting and cracking of skin.

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Safety

Flammability

The most common hazard associated with acetone is its extreme flammability. It auto-ignites at a temperature of 465 °C (869 °F). At temperatures greater than acetone's flash point of −20 °C (−4 °F), air mixtures of between 2.5% and 12.8% acetone, by volume, may explode or cause a flash fire. Vapors can flow along surfaces to distant ignition sources and flash back. Static discharge may also ignite acetone vapors.

Health information

Acetone has been studied extensively and is generally recognized to have low acute and chronic toxicity if ingested and/or inhaled. Inhalation of high concentrations (around 9200 ppm) in the air caused irritation of the throat in humans in as little as 5 minutes. Inhalation of concentrations of 1000 ppm caused irritation of the eyes and of the throat in less than 1 hour; however, the inhalation of 500 ppm of acetone in the air caused no symptoms of irritation in humans even after 2 hours of exposure. Acetone is not currently regarded as a carcinogen, a mutagenic chemical or a concern for chronic neurotoxicity effects.

Acetone can be found as an ingredient in a variety of consumer products ranging from

cosmetics to processed and unprocessed foods. Acetone has been rated as a GRAS (Generally Recognized as Safe) substance when present in beverages, baked foods, desserts, and

preserves at concentrations ranging from 5 to 8 mg/L. Additionally, a joint U.S-European study found that acetone‟s "health hazards are slight.

Toxicology

Acetone is believed to exhibit only slight toxicity in normal use, and there is no strong evidence of chronic health effects if basic precautions are followed.

At very high vapour concentrations, acetone is irritating and, like many other solvents, may depress the central nervous system. It is also a severe irritant on contact with eyes, and a potential pulmonary aspiration risk. In one documented case, ingestion of a substantial amount of acetone led to systemic toxicity, although the patient eventually fully recovered.

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Some sources estimate LD50 for human ingestion at 1.159 g/kg; LD50 inhalation by mice is

given as 44 g/m3, over 4 hours.

Acetone has been shown to have anticonvulsant effects in animal models of epilepsy, in the absence of toxicity, when administered in mill molar concentrations. It has been hypothesized that the high-fat low-carbohydrate ketogenic diet used clinically to control drug-resistant epilepsy in children works by elevating acetone in the brain.

 EPA EPCRA Delisting (1995). EPA removed acetone from the list of “toxic

chemicals” maintained under Section 313 of the Emergency Planning and Community Right to Know Act (EPCRA). In making that decision, EPA conducted an extensive review of the available toxicity data on acetone and found that acetone “exhibits acute toxicity only at levels that greatly exceed releases and resultant exposures,” and further that acetone “exhibits low toxicity in chronic studies.”

 Genotoxicity. Acetone has been tested in more than two dozen in vitro and in vivo assays. These studies indicate that acetone is not genotoxic.

 Carcinogenicity. EPA in 1995 concluded, “There is currently no evidence to suggest a concern for carcinogenicity.”(EPCRA Review, described in Section 3.3). NTP

scientists have recommended against chronic toxicity/carcinogenicity testing of acetone because “the prechronic studies only demonstrated a very mild toxic response at very high doses in rodents.”

 Neurotoxicity and Developmental Neurotoxicity. The neurotoxic potential of both acetone and isopropanol, the metabolic precursor of acetone, have been extensively studied. These studies demonstrate that although exposure to high doses of acetone may cause transient central nervous system effects, acetone is not a neurotoxicant. A guideline developmental neurotoxicity study has been conducted with isopropanol, and no developmental neurotoxic effects were identified, even at the highest dose tested.

 Environmental. When the EPA exempted acetone from regulation as a volatile organic compound (VOC) in 1995, EPA stated that this exemption would “contribute to the achievement of several important environmental goals and would support EPA‟s pollution prevention efforts.” 60 Fed. Reg. 31,634 (June 16, 1995). 60 Fed. Reg. 31,634 (June 16, 1995). EPA noted that acetone could be used “as a substitute

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