Seminars Unit Operations I

Seminars

Unit Operations I

Syllabus:

I Material balances II Material balances with chemical reaction III Fluid flow in pipes IV Filtration V Balances of enthalpy VI Heat transfer VII Heat exchangers VIII Evaporation IX Extraction X Distillation XI Multi-stage distillation XII Drying XIII Reactors XIV Tables

Seminars given by: Michal Kordač, Dept. of chemical Engineering [email protected] Room No.: B T04

ICT Prague, Dept. of chemical engineering Unit Operations I 2013

I Material balances

I.1 From 59 kg of water solution of hydrochloric acid containing 36 wt.% HCl should be prepared a 10 wt.% solution. What amount of water should be added?

Result: 153.4 kg of water should be added to the original solution. I.2 At the outlet from an electrolyser, chlorine gas contains 1.6 vol.% of oxygen. To measure

its flow rate, more oxygen is added into the stream and the final oxygen content is measured. Adding 20 kg of oxygen within 5 minutes and 33 seconds produced the final oxygen concentration 3.6 vol.%. Determine the volumetric flow-rate of the chlorine stream from the electrolyser at 20°C and 100 kPa.

Result: Volumetric flow-rate from the electrolyser at given conditions is 2.2 m3.s-1. I.3 100 kmol of a mixture containing 35 mol.% of phenol, 40 mol.% of cresol, 20 mol.% of

xylenol and 5 mol.% of heavier aromatic alcohols is separated by distillation. Two streams are obtained: distillate containing 95 mol.% of phenol and 5 mol.% of cresol, and bottom product. The distillate contains 90 % of phenol from the original mixture (the feed). Determine amount of both products in kmol and composition of the bottom product.

Result: 33.2 kmol of distillate and 66.8 kmol of bottom product is obtained. the bottom product contains 5.2 mol.% of phenol, 57.4 mol.% of cresol, 29.9 mol.% of xylenol and 7.5 mol.% of heavier aromatic alcohols. I.4 So called ‘corn extract’ (obtained as a waste of corn starch production) contains 50 wt.% of

water, 2.5 wt.% of fructose and the rest are insoluble parts of corn. The beet molasses contains 50 wt.% of sucrose, 1 wt.% of fructose, 18 wt.% of water and the rest are insoluble particles. The extract should be mixed with the molasses and water in an agitated tank. For one batch is fed 125 kg of corn extract and 45 kg of beet molasses. What amount of water must be fed into the batch to obtain a mixture with 2 wt.% of fructose? What is the content of sucrose in the batch after mixing?

Result: We have to add 8.75 kg of water. Final batch will contain 12.6 wt.% of sucrose, the total I.5 The raw material for a vegetable oil production contains 28 wt.% of fat and 10 wt.% of

water. By pressing we obtain oil consisting from 80 wt.% of fat and 20 wt.% of water. The rest from pressing still contains 10 wt.% of fat is extracted by hexane. The hexane is stripped from the extract and recycled. The fat is added into the oil from press to obtain final product. The waste from extraction is dried and finally it contains only 0.2 wt.% of fat and 5 wt.% of water. What is the composition of the final product? What fraction of the fat is obtained by extraction based on total production of fat?

Result: The final product consists of 15.6 wt.% of water and 84.4 wt.% of fat. Extraction is producing 26.2 % of the fat.


II Material balances with chemical reaction II.1 2000 kg of nitration mixture is to be prepared using 1200 kg spent acid solution which

consists of 68 wt.% of H2SO4, 22 wt.% of HNO3 and 10 wt.% of H2O. The final nitration mixture has to consist of 63 wt.% of H2SO4, 28 wt.% of HNO3 and 9 wt.% of water. Limited amounts of nitric acid (containing 82 wt.% HNO3), sulphuric acid (containing 92 wt.% of H2SO4) and oleum (containing 20 wt.% of SO3 and 80 wt.% of H2SO4) are available for the preparation. What will be the consumption of the acids and oleum?

Result: For the nitration mixture preparation, 361 kg of nitric acid, 118 kg of sulphuric acid and 321 kg of oleum are to be added.

II.2 Analysis of a sample of coal showed, it consists of 82 wt.% of carbon, 5 wt.% of water, 2 wt.% of hydrogen, 1 wt.% of oxygen and 10 wt.% of ashes. What amount of air is needed to burn 1 kg of coal in case the air has to be used in 20% excess?

Result: The amount of air is 12.1 kg.

II.3 1000 kg of the pyrite ore containing 85 wt.% of FeS2 and 15 wt.% of waste rock, is oxidized in 100% excess of air. The reaction is as follows:

4 FeS2 + 11 O2 == 2 Fe2O3 +8 SO2 Waste does not react with oxygen and does not release any volatile components. The residuum after the oxidation contains 2 wt.% of FeS2. Calculate: a) Fe content in the residuum (in wt.%), b) the volume of air used at 20 °C and 0.0981 MPa, c) the volume and composition (in mol.%) of the outgoing gas at 300 °C and 0.0981 MPa, d) conversion of FeS2

Results: a) The solid residuum contains 54.9 wt.% of Fe b) 4610 m3 of air at 20°C and 0.0981 MPa is needed for the oxidation process c) The volume of the outgoing gas is 8760 m3 and its composition is 7.7 mol.% of

SO2, 11.0 mol.% of O2 and 81.3 mol.% of N2 d) Conversion of FeS2 is 98.3%.

II.4 Propane C3H8 is burned by 50% excess of air. What volume of air at 25 °C and 98 kPa is

necessary for burning 0.5 m3 of propane at 25 °C and 100 kPa? Assume that propane is fully burned to CO2 and H2O.

Result: 18.2 m3 of the air is necessary for burning of 0.5 m3 propane.

II.5 Formaldehyde is produced by a catalytic oxidation of methanol. Air and methanol vapour are fed into a reactor at volumetric ratio 6:1 at the same pressure and temperature. Conversion of methanol is 30%. Determine the gas composition leaving the reactor (in vol. %).

Result: The composition of the outgoing gas mixture is 9.79 vol.% of methanol, 15.52 vol.% of oxygen, 66.29 vol.% of nitrogen, 4.20 vol.% of formaldehyde and 4.20 vol.% of water.


III Fluid flow in pipes III.1 200 litres per second of mineral oil flows through a horizontal pipe. The pipe is made of

rusty steel with 500 mm diameter and 1 km length. The oil density is 900 kg.m-3 and its dynamic viscosity is 0.01 Pa.s. Calculate the rate of energy dissipation in the pipe.

Result: The energy losses are 5.03 kW.

III.2 A plastic pipe with diameter 60 mm is used for pumping water to the top of a building from a fire hydrant on the street. The building is 25 m high. The necessary pipe length is 160 m. The pressure of water in the hydrant is 1.6 MPa. The flow rate of water is 36 m3.h-1. What pressure will be at the end of the pipe. The local frictions in the pipe can be neglected.

Result: The pressure of water at the end of the pipe will be 1.08 MPa.

III.3 Water flows from a reservoir into a turbine through a new steel pipe, the inner diameter of which is 240 mm. The level of water in the reservoir is 62 m above the turbine and the inlet of the pipe is located 2 m below the level. The length of the pipeline is 600 m. A nozzle with diameter 80 mm is placed at the entrance into the turbine, in which the pressure is 9.81 kPa below atmospheric pressure. The minimum temperature of water is 12°C. Determine: - what would be the mean velocity of water coming out of the nozzle if the

water was taken as ideal fluid - what will be the water velocity in real case

Result: The velocity of ideal fluid in the nozzle would be 35.4 m.s-1, the velocity of water will be 27.9 m.s-1.

III.4 Motor oil SAE10W-30 flows through a pipe DN200 (outer diameter 0.219; wall thickness

8.2 mm) at 20°C. Determine the maximum oil velocity at which the flow would be classified as laminar and calculate the volumetric flow rate. Kinematic viscosity of the oil at given conditions is 9.5 10-5 m2s-1.

Result: The velocity will be 1.08 m.s-1 and the volumetric flow rate 0.0348 m3s-1. III.5 Determine volumetric flow rate of water at 20°C, which flows through new steel pipe

DN150 (outer diameter 0.168 m; wall thickness 7.1mm). The pressure drop must be lower than 35 kPa per 100 m of the pipe length. The pipe is placed horizontally.

Result: The volumetric flow rate is 0,044 m3s-1. III.6 Mineral oil is pumped through a horizontal pipe with a pump at the rate of 3800 m3 per

day. The pipe is made of new steel with roughness 0.2 mm. The length of the pipe is 32 km and its internal diameter is 219 mm. The pressure is equal at both ends of the pipe. The pump efficiency is 0.65 and the efficiency of electromotor including mechanical transmission is 0.88. The oil density is 900 kg.m-3 and viscosity is 0.04 Pa.s. Calculate the consumption of the electric energy consumed by the pump during 24 hours. Assume that by using the pump the oil pressure at the input to the pipe is equal to that at the end.

Result: Consumption of the electric energy by the pump is 6.16 MWh per day.

III.7 Water is pumped between two tanks at temperature 4°C. The vertical difference between the levels in the tanks is 50 m, and the water is pumped from the lower tank into the upper.


The connecting pipeline is made of new stainless steel tube with inner diameter 100 mm. The specific dissipated energy in the suction part of the pipeline is 15.3 J.kg-1. The discharge part of the pipeline has length of 400m and the sum of the form friction factors is 9.2. The mean velocity of the water is 1.3 m.s-1. The pump efficiency is 0.76. Determine the volumetric flow rate of water and the pump power consumption.

Result: The volumetric flow rate of water is 0.01 m3.s-1, the pump power is 8 kW.

III.8 Petrol is running through a straight sloping steel pipe, the walls of which are having roughness of 0.5 mm. The height (relative to a reference level) of the upper end is 83 m and overpressure at this point relative to the pressure at the lower end is 2500 Pa. The lower end of the pipe lies at height of 65 m and the petrol freely flows into a tank open to atmospheric pressure. The length of the pipe is 965 m and its internal diameter is 0.14 m. Determine the volumetric flow of petrol through the pipe. The petrol density is 790 kg.m-3 and dynamic viscosity under the given flow conditions is 2.92 10-4 Pa.s.

Result: The volumetric flow is 0.02 m3 s-1.

III.9 Diesel (ρ = 815 kg m-3, η = 2.45 10-3 Pa s) is pumped at 20°C from a railway tank carriage to an underground tank through slightly rusted steel pipe with the length of 48 m and the internal diameter of 50 mm. Both tanks are open to the atmosphere during the pumping. Calculate how long it takes to discharge the car tank, initially containing 40 m3 of diesel oil by using a centrifugal pump with the characteristic shown in table. For the sake of simplicity, one can assume that the vertical distance between the levels in both tanks is 6 m and is constant during the discharge.

Characteristic of the centrifugal pump (3M 40-160/3.0): V [l min-1] 200 250 300 333 400 450 500 550 600 650 700

H [m] 30.0 29.0 28.5 27.3 26.2 25.4 24 22.5 21 19.2 17.5 Result: The tank is discharged in 83 min.

III.10 Water is pumped from lower tank into an upper one. The vertical difference between the

levels is 16.7 m. The pipeline length is 100 m, the diameter is 100 mm and there is installed a strainer, straight valve and 3 elbows 90°. Assume the friction factor has constant value 0.038 in the range of flow rates 400 – 1000 l.min-1. The pump characteristics is given by the chart below. Determine the flow rate of water at temperature 20°C, which will be provided by a centrifugal pump. Characteristic of the centrifugal pump:


Result: The volumetric flow rate of the water is 703 l.min-1.

0

5

10

15

20

25

30

0 200 400 600 800 1000 1200 1400

Pum

p he

ad [m

]

Q [l.min-1]


Figure III-1 Moody's diagramm for friction coeffitient

Equations for friction factor calculation:

Laminar regime, circular tube Re < 2300

𝜆 =64𝑅𝑒

Transient and turbulent regime Re > 2300

𝜆 =0.25

�𝑙𝑜𝑔 ��6.81𝑅𝑒 �

0.9+ 𝜀 𝑑⁄

3.71��2

Concrete, rough 3 mm Cast iron, new 1 mm Concrete, smooth 0.6 mm Cast iron, slightly corroded 1.5 mm Steel, new 0.2 mm Cast iron, rusty 3 mm Steel, slightly corroded 0.3 mm Glass, plastics 0.01 mm Steel, rusty 1 mm rubber 0.03 mm Steel, zinced 0.2 mm copper 0.05 mm Table III-1 Absolute roughness of tubing materials


Fitting ξ Fitting ξ Elbow, standard Gate valve

45° 0.35 half open 4.50 90° 0.75 fully open 0.17

Elbows, welded Ball valve, fully open 0.05 90° bends, radius 2d 0.19 Butterfly valve, fully open 0.85 90° bends, radius 4d 0.16 Angle valve, fully open 2.00 90° bends, radius 6d 0.21 Globe valve, fully open 6.00

Tee Swing check valve 1.00 straight through 0.40 Lift check valve 10.0 used as elbow 1.00 Foot valve with strainer (popped

disc) 8.00

Return bend, 180° 1.50 Foot valve with strainer (hinged disc)

1.40

Table III-2 Loss coefficients of pipe fittings


IV Filtration IV.1 The water suspension of the solid particles is filtered on an industrial filter with the cross-

sectional area of 2.65 m2. The filtration time is 1 hour and filtration is running under a constant pressure difference. During an experimental laboratory filtration utilizing a filter with the cross-sectional area of 0.085 m2 and with the same operating conditions as during industrial filtration one can obtain 30 dm3 of the filtrate in 8 minutes and 60 dm3 of the filtrate in 18 minutes. What is the volume of the filtrate from the industrial filter per one filtration cycle?

Result: The volume of the filtrate is 4.68 m3 per one filtration cycle.

IV.2 The frame filter press with the overall filtration area of 10 m2 is used for filtration of

1.09 m3 of water suspension with the density of 1175 kgm-3. Filtration is realized under constant filtration rate. Suspension contains 15 wt.% of the solid phase and the cake wetness is 35 wt.%. What maximal volume of the washing water can be used for washing of the cake if the duration of the filtration cycle cannot take more than 90 minutes? The removal of the cake and the filter preparation for another cycle takes 15 minutes. The washing of the cake is operating under the same pressure difference as the filtration. The filtrate and washing water temperatures are equal. During experimental filtration one can find that the filter medium resistance should be neglected and the filtration constant is KF = 3.78 10-6 m2s-1

Result: 0.185 m3 of the washing water may be used.

IV.3 The frame filter press with 8 frames with dimension 700 x 700 x 25 mm is filtrating water

suspension containing 15 vol.% of solids. Filtration runs at constant filtration rate for 3 hours 36 minutes. After filtration the cake is being washed for 54 minutes with water. Filtration constants were obtained experimentally at identical conditions: KF = 3.125 10-4 m2h-1 and qM = 3.125 10-5 m. Calculate the amounts of suspension, filtrate, washing water and volumetric content of water in the cake.

Result: In the cycle, 0.361 m3 of suspension is processed obtaining 0.263 m3 of filtrate, 0.0164 m3 of washing water. The cake contains 44.8 vol.% of water.

IV.4 Determine the amount (mass in tons) of aqueous suspension is possible to process during 1

hour filtration by a filter with filtration are 50 m2. The filtration is to be made at constant pressure difference of 152 kPa and temperature 20°C. On an experimental filtration unit with filtration area 0.1 m2 with at pressure difference of 101 kPa was obtained 5 dm3 of filtrate in 200 s and 14 dm3 of filtrate after 1500 s. The suspension contains 10 wt.% of solid phase and the content of moist in the cake is 32 wt.%. The temperature and the filtration membrane are the same in both, the experiment and process.

Result: 15.70 tons of suspension will be processed during 1 hour.


V Balances of enthalpy V.1 A production line requires a supply of 6 tons of hot water per hour. The water enters the

line with temperature 60°C and cools down to 38°C at the outlet. The water is re-heated in a heat exchanger, where steam at pressure 150 kPa is used. The steam condensate is leaving the heat exchanger at 86°C. What is the consumption of steam in the heat exchanger?

Result: The mass flow rate of steam is 237 kg.h-1.

V.2 In a condenser of a distillation column, 120 kg.h-1 of vapour containing 95 mol.% of methanol and 5 mol.% of ethanol is fully condensed at mean temperature 65°C. The cooling water enters the condenser at 15 °C and leaves at 35°C. Determine the flow rate of cooling water.

Result: The mass flow rate of cooling water is 1.5 t.h-1.

V.3 Crusted ice in amount of a) 20 kg, b) 80 kg and with temperature of 0 °C was added to a tank containing 100 kg of water at temperature of 25 °C. Crusted ice consists of 70 wt.% of ice and of 30 wt.% of water. Calculate resulting amount, composition and temperature in the tank. The latent heat of melting of ice is 334 kJ.kg-1. The average specific heat of water is 4.2 kJ.kg-1K-1.

Result: a) all ice has been melted, i.e. tank contains 120 kg of water at 11.6 °C.

b) Ice in the tank has been melted only partially, i.e. temperature is 0 °C and the tank contains 180 kg of crusted ice with composition of 13.6 wt.% of ice and 86.4 wt.% of water.

V.4 A reboiler of a distillation column requires heat flow of 5.8 kW. Steam of 130°C is going to

be used for heating. Calculate the mass flow rate of the steam in case a) the steam is dry; b) the steam contains 6 % of condensate.

Result: The mass flow rate of steam is a) 9.6 kg.h-1 or b) 10.2 kg.h-1.

V.5 What amount of steam is necessary for heating of 2000 kg of water from 20 to 50 °C.

Steam saturated at atmospheric pressure is used and we can assume the heat is gain by condensation only (no subcooling of condensate). The heat loss represents 6 % of total heat flux.

Result: 118 kg of saturated steam is used.

V.6 A mixture of water vapour and ethylene is cooled from 200°C down to 25°C in a counter-current heat exchanger. The water vapour is partially condensing in the heat exchanger. The gas and the condensate at the outlet have pressure 100 kPa and temperature is the same for both phases. The gas is saturated with water vapour at the outlet, while ethylene does not dissolve in the condensate, which is composed of pure water. The total mass flow rate of


the hot gas is 1200 kg.h-1, from which 200 kg.h-1 is water. Calculate mass flow rate of cooling water, which is heated from 15°C to 80°C. Assume the heat losses are negligible.

Result: It is necessary to supply 3.06 tons of cooling water per hour.


VI Heat transfer

Heat conduction VI.1 Internal temperature in an oven is 1400°C. The temperature of the outer wall should not

exceed 50°C. The heat flux is 250W.m-2. The wall of the oven should be made of two layers, inner made of heat resistant bricks (heat conductivity 0.25 W.m-1K-1) and outer made of rock wool (heat conductivity 0.05 W.m-1.K-1). The maximum temperature, at which the rock wool is not damaged, is 1100°C. Determine the thickness of both layers, if the wall can be taken as flat.

Result: The thickness of the inner layer is 30 cm, the thickness of the outer layer is 21 cm.

VI.2 A coolant is transported in a pipe with external wall temperature of -30 °C and with outer

diameter of 10 cm. The tube is thermally isolated by two layers: 1) an internal layer of foamed polypropylene with thermal conductivity of 0.08 W.m-1.K-1 and thickness of 10 cm, and 2) an external felt layer with thermal conductivity of 0.05 W.m-1.K-1 and thickness of 5 cm. Temperature of the outer surface is 25 °C. Calculate the heat flow from the surroundings to the tube with length of 100 m. What is the temperature on the boundary between polypropylene and felt layers?

Result: The heat flow from the surroundings is approx. 1.77 kW. Temperature between layers of isolation is 8.8 °C.

VI.3 A cooling coil is made of steel tubing 38x2.5 mm. Its outer surface is to be covered by an acid resistant layer, 0.5 mm thick and heat conductivity 0.6 W.m-1.K-1. What is going to be the change of the resistance of the tube wall to heat transfer?

Result: The resistance of the wall will increase by a factor of 17.

Heat convection VI.4 0.25 kg.s-1 of benzene flows through 1.8 m long copper pipe. The outer diameter of the pipe

is 20 mm and wall thickness is 2mm. The mean temperature of benzene is 40°C. Calculate the heat transfer coefficient on the side of benzene.

Result: The heat transfer coefficient is 2.00 kW.m-2.K-1.

Missing: Properties of Benzene at 40C : rho = 860.7 kg/m3, eta 0.4965 mPas, lambda = 0.142 W/m.K, cp = 1870 J/kg.K. VI.5 Cooling oil is being cooled in horizontal heat exchanger with tube bundle. The bundle

consists of 37 tubes with length of 2 m and 38 mm outer diameter. The shell is a tube with internal diameter of 350 mm. The oil flows through the shell space of the heat exchanger and its mean velocity is 0.15 m.s-1. The mean temperature of the oil is 65°C, mean temperature of the tube walls is 60°C. The properties of oil at 65°C are: density 850 kg.m-3;


kinematic viscosity 10-5 m2.s-1; heat conductivity 0.12 W.m-1.K-1; heat capacity 2.12 kJ.kg-

1.K-1; volumetric expansion coefficient 4.10-4 K-1. Dynamic viscosity of the oil at 60°C is 9.8 mPa.s. Calculate the heat transfer coefficient on the side of oil.

Result: The heat transfer coefficient is 66.9 W.m-2.K-1.

Calculation of the heat transfer coefficient: Basic dimensionless numbers:

Nusselt Nu = α dλ

Prandtl Pr = νa

= η cpλ

Reynolds Re = v dν

= v d ρη

Grashof Gr = β ΔT g d3

ν

Free convection 𝑁𝑢 = 𝐶 (𝐺𝑟 𝑃𝑟)𝑛 values of C and n depend on geometry

Type of heat exchange area Range of validity C n Flat vertical wall Gr Pr < 104 1.36 0.2

104 > Gr Pr < 109 0.59 0.25 109 > Gr Pr . 0.13 0.333

Horizontal cylinder, outer surface

Gr Pr < 10-5 0.49 0 10-5 > Gr Pr < 10-3 0.71 0.04 10-3 > Gr Pr < 1 . 1.09 0.10 1 > Gr Pr < 104 1.09 0.20 104 > Gr Pr < 109 0.53 0.25 109 > Gr Pr . 0.13 0.333

Forced convection Laminar flow

𝑁𝑢 = 3.66 +0.19�𝑅𝑒𝑃𝑟𝑑𝐿�

0.8

1+0.117�𝑅𝑒𝑃𝑟𝑑𝐿�0.467 �

𝜂𝜂𝑤�0.14

0.1 < (Re Pr d/L) < 10000

Transient flow

Nu = 0.116(Re2 3⁄ − 125) Pr1/3 �1 + �dL�2/3� � η

ηw�0.14

2100 < Re < 10000 Turbulent flow Nu = 0.023 Re0.8 Pr0.4 104 < Re < 2 106; L/d > 50; 0.7 < Pr < 170


VII Heat exchangers VII.1 Calculate heat transfer area of a plate heat exchanger which is used for cooling of oil. Mass

flow rate of oil is 2 kg.s-1 and it is cooled from temperature of 65 °C to 25 °C. Water with inlet temperature of 20°C and with outlet temperature of 40 °C is used as a cooling medium. Overall heat transfer coefficient is 180 W.m-2.K-1 and mean heat capacity of oil is 2 kJ.kg-1.K-1.

Result: Heat transfer area is 71.5 m2.

VII.2 Reaction mixture is cooled from temperature of 150 °C to 80 °C in a counter-current heat

exchanger with a bundle of tubes in a shell by cooling water. Mass flow of the mixture is 1.0 kg.s-1. The bundle consists of seven tubes made of steel with external diameter of 25 mm and with wall thickness of 2 mm. Internal diameter of the shell is 150 mm. The reaction mixture with average thermal capacity of 2 kJ.kg-1.K-1 is running inside tubes whilst water with average thermal capacity of 4.2 kJ.kg-1.K-1 is running in shell-space. Heat loss to the surroundings can be neglected. Input temperature of water is 15 °C and output temperature is 25 °C. Heat transfer coefficient inside the tube is 1000 W.m-2.K-1. Calculate overall heat flow, mass flow of water, heat transfer coefficient on the outer side of the tube, overall heat transfer coefficient and the length of exchanger.

Result: Total heat flow is 140 kW, mass flow of water is 3.33 kg.s-1, heat transfer coefficient on the outer tube side is 1055 W.m-2.K-1, overall heat transfer coefficient is 35.9 W.m-1.K-1 and the length of exchanger is 6.06 m.

VII.3 Vapour of pure ethanol at 78°C is fed into a counter current condenser. All of the vapour is condensed and then the condensate is subcooled to 20°C. As a cooling media, 0.28 kg.s-1 of cooling water is used. The water enters at temperature of 10°C and leaves at 65°C. The overall heat transfer coefficient for condensation is 1400 W.m-2.K-1, for the cooling part its value is 230 W.m-2.K-1. Determine the capacity of the condenser given as kg of ethanol processed per hour and the heat transfer area. Assume, that the condenser may be splitted to condensation and subcooling parts.

Result: The condenser is able to process 223 kg.h-1 of ethanol and the total heat transfer area is 2.74 m2.

VII.4 In a counter-current heat exchanger, 1.7 kg.s-1 of naphta is cooled from temperature 90°C

to 20°C. The heat capacity of the naphta is 2.5 kJ.kg-1.K-1. The naphta flows through the shell space. 2 kg.s-1 of cooling water enter at 15°C and flow through a bundle consisting of 37 tubes, the outer diameter of which is 32mm and wall thickness is 3.5 mm. The bundle is 6 m long. Determine the overall heat transfer coefficient.

Result: The overall heat transfer coefficient is 80 W.m-1.K-1.


VIII Evaporation VIII.1 1500 kg.h-1 of caustic soda (NaOH) solution is to be concentrated from 10 wt.% to

30 wt.% in an evaporator. The solution enters the evaporator at 30°C. Steam of temperature 130°C is used for heating, no condensate sub-cooling is observed. The pressure in the evaporator is 101.3 kPa. Any heat losses can be neglected. The average heat capacity of NaOH is 1.5 kJ.kg-1.K-1. Calculate consumption of steam for the heating.

Result: 1270 kg.h-1 of the steam is needed.

VIII.2 A single effect evaporator is to concentrate 2000 kg.h-1 of aqueous glycerol solution from

13 wt.% to 80 wt.%. The feed is pre-heated from 30°C to 60°C in a heat exchanger by waste vapour from the evaporator. Pressure in the vapour space is 33.3 kPa. Temperature of steam used for heating is 110°C and it’s dryness 0.97 (i.e. the steam contains 97 wt.% of vapour and the rest is droplets of equilibrium condensate). Boiling temperature of 80 wt.% solution of glycerol at pressure of 33.3 kPa is 92°C and its specific heat capacity is 2.554 kJ.kg-1K-1. Specific heat capacity of 13 wt.% solution is 3.559 kJ.kg-1K-1. Calculate consumption of steam and what part of waste vapour is used in the pre-heating.

Result: Consumption of steam in the evaporator is 1900 kg.h-1. 5.47 % of waste vapour is reused in the pre-heating.

VIII.3 In magnesium mining, a solution containing 7 wt.% of MgCl2 is obtained by ore digestion

in hydrochloric acid. The solution has to be concentrated to 25 wt.% in an evaporator. 2000 kg.h-1 of the solution at 20°C has to be processed. The evaporator is heated by saturated steam with temperature 130°C and the pressure in the evaporator is kept at 50 kPa. The heat transfer coefficient in the evaporator is 2000 W.m-2.K-1. Determine the consumption of the steam and heat transfer area of the evaporator.

Result: Consumption of steam in the evaporator is 1740 kg.h-1. The heat transfer area is 14.3 m2.


IX Extraction with immiscible solvents IX.1 13 kg of a mixture containing 8 wt.% of acetone in toluene was mixed at 20°C with:

a) 7 kg of water b) Solvent consisting of 25 kg of water and 0.5 kg of acetone.

After mixing, phases were split. Determine weight fraction of acetone in both phases and fraction of acetone transferred into water in each case.

Result: a) raffinate contains 4.8 wt%; extract contains 5.9 wt.% and contains 42.2% of

acetone. c) raffinate contains 3.3 wt%; extract contains 4.4 wt.% and contains 60.4% of

acetone.

IX.2 6 kg of a mixture containing 5.1 wt.% of acetone and 94.9 wt.% of toluene was mixed with

4 kg of pure water at 20°C. Determine:

d) equilibrium composition of the final phases e) the efficiency of the extraction, if raffinate contained 3 wt.% of acetone.

Result: In equilibrium, the extract contains 3.7 wt.% of acetone and 96.3 wt.% of water

and the raffinate 2.6 wt.% of acetone and 97.4 wt.% of toluene. The efficiency of the extraction is 85.6 %.

IX.3 10 kg of a mixture containing 13 wt.% of acetone and 87 wt.% of water is extracted by a

solvent containing 99 wt.% of o-xylene and 1 wt.% of acetone. Mixer-settler extraction is used and 5 kg of solvent is added to each stage. What is the composition of the raffinate after extraction in two stages? What is mass fraction of acetone in the combined extracts from both stages in the case of equilibrium stages and in the case of real stages with stage efficiency of 0.75? Extractors are operated at 30 °C.

Result: Composition of the raffinate from the second equilibrium stage is 7.4 wt.% of

acetone and 92.6 wt.% of water. Composition of the raffinate from the second real stage is 8.7 wt.% of acetone and 91.3 wt.% of water. The mass fraction of acetone in combined extracts is 0.066 in the case of equilibrium stages and 0.054 in the case of real stages.

IX.4 For acetone removal from 10 kg of a mixture, which contains 8 wt.% acetone and 92 wt.%

of water, 50 kg of extraction solvent is available. The solvent contains 1 wt.% of acetone and 99 wt.% of toluene. After the extraction, at most 2 wt.% of acetone should remain in the water. How many equilibrium stages are necessary if the same amount of solvent is used in each stage (i.e. the solvent is splitted into equal parts for each extraction)? Extraction is operated at 20 °C.

Result: 4 equilibrium stages are necessary.


IX.5 0.20 kg.s-1 of water solution containing 8.5 wt.% acetone is extracted in a counter-current plate extraction tower by pure toluene. Efficiency of acetone removal is 80%. Extraction is operated at 20 °C. Calculate:

a) minimum flux of the extraction solvent b) number of equilibrium stages for 1.5 times the minimum flux of the extraction solvent

Result: a) Minimal consumption of the extraction solvent is 0.175 kg.s-1.

b) Number of equilibrium stages for given solvent flux is 3.9. IX.6 90% of the acetone is to be recovered by counter-current extraction from water into organic

solvent. The feed contains 9.1 wt.% of acetone and pure solvent is used. The feed to solvent ratio of mass flow rates is 1.22. The extraction is made at 20°C, the equilibrium at this temperature can be given as 𝑌𝐴∗ = 1.42 𝑋𝐴∗. Determine the height of the extraction column, if the height equivalent to a theoretical stage is 0.75 m.

Result: The height of the extractor is 3.6 m (4.8 extraction stages).


X Distillation

Flash distillation X.1 1 kg.s-1 of a mixture, which contains 45 wt.% of ethanol and 55 wt.% of butanol is fed into

a still at atmospheric pressure where it is separated by flash distillation. 0.43 kg.s-1 of vapour has been obtained. Calculate composition of vapour, composition of liquid and the temperature of distillation.

Result: Vapour contains 66.8 wt.% of ethanol and 33.2 wt.% of butanol, liquid contains 28.5 wt.% of ethanol and 71.5 wt.% of butanol. The temperature of the distillation is 94 °C. X.2 A feed of composition 32 wt.% benzene and 68 wt.% toluene is to be separated by flash

distillation at a temperature of 70°C such that the feed separates into 60% mass vapour and 40% mass liquid phase. Determine the composition of the distillate and bottom products and the pressure at which the separation is performed. Assume that the mixture is ideal.

Result: The distillate contains 40.1 wt.% benzene and 59.9 wt.% toluene. The bottom product contains 19.8% mass benzene and 80.2% mass toluene. The required pressure 37.6 kPa X.3 A feed of composition 72 mol.% hexane and 28 mol.% octane is to be separated by flash

distillation at 480 mBar. The bottom product contains 60 mol.% of octane and 8.6 mol.s-1 of bottom product is produced. Determine the composition of distillate, flow rate of the feed and the temperature at which the separation is performed. Assume that the mixture is ideal.

Result: The distillate contains 81.1 mol.% of hexane and 18.9 mol.% of octane. The flow rate of the feed is 38.9 mol.s-1. The distillation temperature is 67.4°C

Batch distillation X.4 100kg of a mixture containing 40% mass benzene and 60% mass toluene is to be processed

by differential distillation under normal pressure. The bottom product is to contain 20% mass benzene. Determine the mass fraction of benzene in the distillate and the mass of distillate. Perform the calculation for a mean value of the relative volatility of benzene to toluene 2.50.

Result: The mass fraction of benzene in the distillate is 0.528 and the distillate has a mass of 61kg


XI Multi-stage distillation XI.1 Top product (distillate) which contains 92 mol.% of heptane and bottom product (waste)

containing 6 mol.% of heptane are produced in a continuous rectification column with equilibrium reboiler and total condenser. Feed contains 52 mol.% of heptane and 48 mol.% of octane and is introduced to a column at its boiling point. Process is running at atmospheric pressure. Calculate:

a) amount of heptane (in %) which is transported from feed to top product, b) minimum number of equilibrium stages and minimum reflux ratio, c) number of equilibrium stages and feed plate if the reflux ratio is twice the

minimal. Result: a) 95% of heptane from feed is removed to top product,

b) Minimum number of equilibrium stages is 6, minimum reflux ratio is 1.22, c) Number of equilibrium stages for R=2Rmin is 9.5 and feed is introduced to the

fifth plate from the top.

XI.2 An equimolar mixture of ethanol and butanol is to be separated in a distillation column with total condenser and equilibrium reboiler. 6400 kg.h-1 of the mixture is fed into the column at 20°C. The column produces 2400 kg.h-1 of distillate containing 95 mol.% of ethanol. The reflux ratio is twice the minima. The mean plate efficiency is 0.55. Steam of pressure 3 bar is used in the reboiler. In condenser, cooling water is being heated by 20°C. Calculate:

a) number of equilibrium stages and number of real stages, b) amount of steam and cooling water being consumed in the process.

Result: a) 5.7 theoretical and 9 real stages is necessary,

f) 2.18 t.hr-1 of steam and 37.6 t.hr-1 of cooling water is needed. XI.3 2500 kg/h of mixture containing 40 wt.% of methanol and 60 wt.% of water is separated in

a distillation column. Distillate containing 96 wt.% of methanol and bottom product containing 98 wt.% of water are obtained as final products. The mixture is taken from a tank at 20°C and before injecting into the column is pre-heated to its boiling point. The column operates at normal pressure and reflux ratio1.5 is used. Steam of pressure 3 bar is used in the reboiler and pre-heater. In condenser, cooling water is being heated by 20°C. Assume negligible heat losses and constant values of heat capacities of methanol (cPA = 2.59 kJ.kg-1.K-1) and water (cPB = 4.18 kJ.kg-1.K-1).

Calculate: a) mass flow rates of bottoms and distillate, b) amount of steam and cooling water being consumed in the process.

Result: a) 1490 kg.hr-1 of bottom product and 1010 kg.hr-1 of distillate is produced,

b) 1.69 t.hr-1 of steam and 36 t.hr-1 of cooling water is needed.


XII Drying XII.1 What is relative specific enthalpy and humidity (relative mass fraction of water) in air when

temperature is 60 °C and relative humidity is 40 % ? Result: Relative specific enthalpy of wet air is 203 kJ.kg-1 and its humidity is YA = 0.0545. XII.2 What is dew-point temperature and partial pressure of water in air with temperature of

70 °C and with wet-bulb temperature of 42 °C? Result: Dew-point temperature is 37.6 °C. Partial pressure of water is 6.45 kPa. XII.3 Air with dew-point temperature of 16 °C is heated from 26 °C to 82 °C in a warm-air

furnace. Calculate specific energy consumption (energy spent per one kilogram of dry air) in a furnace.

Result: The specific energy consumption is 57.8 kJ.kg-1. XII.4 Wet air parameters can be obtained from a psychrometer which indicates air temperature

55 °C and wet-bulb temperature 30 °C. For calibration of the psychrometer dew-point temperature of 22.1 °C was determined by a more precise measurement. Is the value obtained from the psychrometer measurement correct?

Result: Air humidity is YA = 0.0170. Value obtained from psychrometer measurement agrees with determination of dew-point temperature. XII.5 What is the lowest possible temperature which can be obtained by cooling a liquid in a

bottle if the bottle is coated by wet cloth and if air with temperature of 25 °C and with relative humidity of 40 % is blowing around the bottle?

Result: The lowest temperature of liquid in the bottle is 16.2 °C and can be determined as wet-bulb temperature. XII.6 240 kg/h of a material is dried from 50 wt.% to 20 wt.% of water in a counter-current

continuous dryer. Inlet temperature of material is 20 °C and its outlet temperature is 35 °C. Specific heat capacity of solid material is 836 J.kg-1.K-1. Air of inlet temperature 24 °C and humidity YA0 = 0.01 is heated in a pre-heater to temperature 70 °C. Outlet temperature of air is 53.5 °C and its outlet humidity is YAe = 0.038. The heat loss through dryer walls and through transport apparatus can be neglected. The heat is applied to the pre-heater as well as to the dryer. Calculate the mass flow of dry air and the overall specific heat consumption. Decide if the output moisture content of water in the material is bigger or smaller than critical moisture content.


Result: Mass flow of dry air through the dryer is 3.21 t.h-1. The specific heat consumption is 3.64 MJ.kg-1. Outlet moisture content is smaller than critical moisture content. XII.7 A wet material is adiabatically dried in a batch dryer for 5 hours at constant parameters of

drying gas. After that mass of wet material is reduced by 20 %. Initial moisture content of material is 28.5 wt.%, critical moisture content is 20 wt.% and equilibrium moisture content is 2.5 wt.%, respectively. Calculate final moisture content if drying time is extended by 2 hours. One can assume that the drying rate during the falling rate period can be approximated by a linear function of moisture content.

Result: By extending the drying time the moisture content drops from 10.6 wt.% to 7.1 wt.%. XII.8 In a batch drier, wet material is being dried at constant air parameters. Initial moist content

is 50 wt.%, the critical moist content of the material is 18 wt.% and equilibrium moist content is 3 wt.%. The drying area of the wet material is 15 m2. The wet material has initial weight of 50 kg, and at the end has 35.7 kg. Determine the drying are if the material is to be dried to finial moist content of 10 wt.% during the same time and at the same conditions. Assume a linear dependence of the drying rate on moist content in the II. period of drying.

Result: The necessary area for drying is 24.7 m2.


Figure XII-1 Psychrometric chart for system Air - Water


XIII Reactors XIII.1 Butyl acetate is produced in a batch reactor from acetic acid and butanol. Determine the

reaction time for 50 % conversion of the acid. Initially, the batch contains butanol and acetic acid (compound A) in molar ratio 4.97 : 1. Calculate the volume of the reactor and amount of each component which is necessary for production of 50 kg.h-1 of ester. Time for cleaning and refilling is 45 min. The reaction rate is described by r = k cA

2, where the reaction constant k = 1.74 10-2 m3.kmol-1.min-1. The density of the reaction mixture can be taken as constant during the reaction period. Density of acetic acid and butanol is 958 kg.m-3 and 742 kg.m-3, respectively. Assuming constant density, the initial concentration of acetic acid can be calculated as follows:

BBBAAA

A

BBAA

A

BA

AA MnMn

nmm

nVV

nc

ρρρρ //// 00

0

00

0

00

00 +

=+

=+

=

Result: The volume of the reactor is 0.62 m3. Feed contains 66.6 kg of acetic acid and 409 kg of butanol. The reaction time is 32.1 min. XIII.2 Reaction 2A <==> B + C is carried out isothermally in a continuous stirred tank reactor

(CSTR). Volumetric flow of the reaction mixture is V = 100 m3.h-1. Concentration of component A at the input to the cascade is cAi = 1.5 kmol.m-3, input concentration of components B and C is cBi = cCi = 0. The rate constant of the forward reaction is k = 5 m3.kmol-1.h-1, the equilibrium constant is K = 16.0. Conversion at the output from the reactor is 80 % of the equilibrium conversion. The kinetic equation for the reaction is give as r = k (cA

2 - cB cC / K). Calculate the volume of the reactor, which is needed to achieve conversion of 0.8ζeq.

Result: The volume of a single reactor is 62.8 m3. XIII.3 A reaction in a liquid phase with constant density 2A + B --> 2C proceeds according to

the expression r = kcA2 in an isothermal tubular reactor (with plug flow). Initial

concentrations are: cA0 = cB0 = 1.5 kmol.m-3, cC0 = 0 kmol.m-3. Conversion of 95 % is required. The feed flow rate is 0.1 m3.h-1 and the rate constant is 0.01 m3.h-1.mol-1. The internal cross-sectional area is 0.002 m2.

a) What is the flow of component C at the output from the reactor? b) What is the length of the reactor? The internal cross-sectional area is 0.002 m2.

Result: a) The flow of component C at the output is 0.143 kmol.h-1

b) The length of the reactor is 31.7 m.


XIV Tables properties of liquid water temperature

[°C] density

[ kg.m-3 ] dynamic viscosity [ mPa.s ]

heat capacity [ kJ.kg-1.K-1]

heat conductivity [W.m-1.K-1]

Prandtl number

[-] 0.01 999.78 1.792 4.229 0.5610 13.51 10 999.69 1.306 4.188 0.5800 9.435 20 998.19 1.002 4.183 0.5984 7.006 30 995.61 0.7977 4.183 0.6154 5.422 40 992.17 0.6532 4.182 0.6305 4.333 50 987.99 0.5470 4.182 0.6435 3.555 60 983.16 0.4665 4.183 0.6543 2.982 70 977.75 0.4040 4.187 0.6631 2.551 80 971.79 0.3544 4.194 0.6700 2.219 90 965.33 0.3145 4.204 0.6753 1.958 100 958.39 0.2818 4.217 0.6791 1.750

properties of steam - water vapour temperature

[°C] Saturated pressure

[kPa]

heat of vaporization

[ kJ.kg-1]

heat capacity [ kJ.kg-1.K-1]

heat conductivity [W.m-1.K-1]

0.01 2500 1.868 0.01707 20 2.31 2454 1.882 0.01823 40 7.36 2407 1.904 0.01960 60 19.9 2359 1.937 0.02118 80 47.4 2309 1.983 0.02301 100 101 2257 2.044 0.02509 120 199 2203 2.126 0.02746 140 361 2144 2.233 0.03014 160 619 2082 2.37 0.03312 180 1002 2014 2.56 0.03644 200 1554 1940 2.80 0.04010 220 2318 1859 3.11 0.04415


Equilibrium pressure, density and enthalpy of saturated water and water vapour as a function of temperature t-temperature, p-pressure, ρl-liquid density, ρv-vapour density, hl-liquid enthalpy, hv-vapour enthalpy, ∆hlv-enthalpy of vapourization

t° C

pkPa

ρ l

kg m-3

ρv

kg m-3

hl

kJ kg-1

hv

kJ kg-1

∆ hl v

kJ kg-1

0.01 0.61173 999.78 0.004855 0.00 2500.5 2500.5 10 1.2281 999.69 0.009405 41.99 2518.9 2476.9 20 2.3388 998.19 0.017308 83.84 2537.2 2453.3 30 4.2455 995.61 0.030399 125.67 2555.3 2429.7 40 7.3814 992.17 0.05121 167.50 2573.4 2405.9 50 12.344 987.99 0.08308 209.33 2591.2 2381.9 60 19.932 983.16 0.13030 251.15 2260.8 2357.6 70 31.176 977.75 0.19823 293.01 2626.1 2333.1 80 47.373 971.79 0.29336 334.93 2643.1 2308.1 90 70.117 965.33 0.42343 376.93 2659.6 2282.7

100 101.32 958.39 0.5975 419.06 2675.7 2256.7 110 143.24 951.00 0.8260 461.34 2691.3 2229.9 120 198.48 943.16 1.1208 503.78 2706.2 2202.4 130 270.02 934.88 1.4954 546.41 2720.4 2174.0 140 361.19 926.18 1.9647 589.24 2733.8 2144.6 150 475.72 917.06 2.5454 632.32 2746.4 2114.1 160 617.66 907.50 3.2564 675.65 2758.0 2082.3 170 791.47 897.51 4.1181 719.28 2768.5 2049.2 180 1001.9 887.06 5.154 763.25 2777.8 2014.5 190 1254.2 876.15 6.390 807.60 2785.8 1978.2 200 1553.7 864.74 7.854 852.38 2792.5 1940.1 210 1906.2 852.82 9.581 897.66 2797.7 1900.0 220 2317.8 840.34 11.607 943.51 2801.3 1857.8 230 2795.1 827.25 13.976 990.00 2803.1 1813.1 240 3344.7 813.52 16.739 1037.24 2803.0 1765.7 250 3973.7 799.07 19.956 1085.32 2800.7 1715.4 260 4689.5 783.83 23.700 1134.38 2796.2 1661.9 270 5499.9 767.68 28.061 1184.57 2789.1 1604.6


Liquid density ρ / kg m-3

Name Formula

0

10

20

30

40

t / °C 50

60

70

80

90

100

Acetic acid (100%) C2H4O2 1072 1061 1049 1039 1027 1016 1005 993 982 970 958 Acetone C3H6O 812 801 790 779 767 755 - - - - - Amyl alcohol C5H12O 828 - 813 - 798 - 783 - 768 - 752 Aniline C6H7N 1039 1030 1022 1013 1004 996 987 978 969 960 - Benzene C6H6 900 889 879 868 858 847 836 825 814 804 793 Butyl alcohol C4H10O 824 817 810 803 795 - - - - - - Chlorobenzene C6H5Cl 1128 1117 1106 1096 1085 1074 1063 1052 - - - Chloroform CHCl3 1526 1508 1489 1470 1451 1432 - - - - - Cyclohexane C6H12 797 788 779 770 760 751 741 - - - - Diethyl ether C4H10O 736 725 714 702 690 678 665 652 640 - 610 Ethyl acetate C4H8O2 925 913 901 892 881 - - - - - - Ethyl alcohol C2H6O 806 798 789 781 772 763 754 745 735 - - Ethylene glycol C2H6O2 1126 1120 1114 1106 1099 1092 1084 1076 1068 1060 1052 Ethylene chloride C2H4Cl2 1282 1268 1254 1239 1226 1209 1194 1179 - - - Glycerol C3H8O3 1273 1267 1261 1255 1249 1243 1236 1230 1223 1216 1209 Heptane C7H16 700 692 684 675 667 658 648 640 631 622 612 Hexane C6H14 677 668 659 650 641 632 622 612 602 591 581 Sulphuric acid (100%) H2SO4 1854 1844 1834 1825 1815 1805 1795 1785 - - - Methyl alcohol CH4O 810 801 791 782 772 763 753 - - - - Methyl chloride CH3Cl 1519 1502 1485 1467 1451 1434 - - - - - Methyl tetrachloride CCl4 1633 - 1595 - 1556 - 1516 1496 1476 1455 1434 Mercury Hg 13595 13570 13546 13521 13497 13472 13448 13424 13399 13375 13351 Naphtalene C10H8 - - - - - - - - 979 970 962 Nitrobenzene C6H5NO2 1223 1213 1203 1193 1183 1173 1163 - - - - Octane C8H18 718 710 702 694 686 678 670 661 653 644 635 Phenol C6H6O - - - - 1058 1049 1040 1031 1022 1013 1003 Pentane C5H12 645 636 626 616 606 596 585 574 563 551 538 Propyl alcohol C3H8O 820 812 804 796 788 780 771 762 753 743 733 Sulphur trioxide SO3 1998 1951 1905 1858 1812 - - - - - - Toluene C7H8 884 875 866 856 847 838 828 818 808 798 788 Xylene (m-) C8H10 882 873 864 856 847 838 830 821 812 803 794 (o-) - - 880 872 863 - - - - - - (p-) - - 861 852 843 - - - - - -


Dynamic viscosity of liquids Experimentally determined viscosities are usually fitted with empirical equations in a form: ln(η) = A + B/ T (V-2) ln(η) = A + B/ T + C T + D T2 (V-3) where η is dynamic viscosity in mPa.s, T temperature in Kelvins and A, B, C, D are empirical constants. Constants given in the table below are valid in the temperature range from tmin to tmax [°C]. Name formula Eq. A B C/ 10-3 D/ 10-6 tmin tmax

Ammonia NH3 (V-3) -19,78 2018 61,73 -83,17 -75 130 Hydrochloric acid HCl (V-3) -3,488 448,1 7,062 -31,68 -110 50 Sulphuric acid H2SO4 (V-2) -6,178 2736 - - 0 80 Sulphur dioxide SO2 (V-3) -6,148 936,5 14,14 -28,87 -70 115 Carbon dioxide CO2 (V-3) -3,097 48,86 23,81 -78,40 -56 30 Methyl tetrachloride CCl4 (V-3) 6,81491 -14,0181 -31,9019 29,8794 -40 180 Chloroform CHCl3 (V-3) -5,88546 1012,35 10,5532 -14,33134 -40 240 Methyl chloride CH3Cl (V-2) -5,073 981,9 - - 0 130 Methanol CH4O (V-3) -8,70441 1538,49 16,874 -23,3899 -40 100 1,2-dichlorethan CH4Cl2 (V-2) -3,926 1091 - - 0 100 Acetic acid C2H4O2 (V-2) -4,519 1384 - - Ethanol C2H6O (V-3) -7,10566 1675,13 10,3679 -17,1008 -50 100 Aqueous ethanol sol. 96% hm. (V-3) -0,641413 1029,56 -108,4 5,650768 0 120 Ethylene glycol C2H6O2 (V-2) -7,811 3143 - - 20 110 Acetone C3H6O (V-2) -4,033 845,6 - - -80 60 Propane C3H8 (V-3) -7,746 721,9 23,81 -46,65 -187 96 n-propanol C3H8O (V-3) -12,28 2666 20,08 -23,3 -72 260 Isopropanol C3H8O (V-2) -8,114 2624 - - 0 90 Methyl ethyl ketone C4H8O (V-2) -4,213 975,9 - - 0 80 Ethyl acetate C4H8O2 (V-2) -4,171 984,1 - - 0 80 n-butane C4H10 (V-2) -3,821 612,1 - - -90 0 n-butanol C4H10O (V-3) -9,722 2602 9,53 -9,966 -60 289 Diethyl ether C4H10O (V-2) -4,267 813,1 - - -80 100 n-pentane C5H12 (V-2) -3,958 722,2 - - -130 40 Benzene C6H6 (V-3) 4,612 148,9 -25,44 22,22 6 288 Phenol C6H6O (V-3) -18,51 4350 24,29 -15,47 41 420 Aniline C6H7N (V-3) -83,8415 11753 207,8 -182,6 -6 50 Cyclohexane C6H12 (V-3) -4,398 1380 -1,55 1,157 7 280 n-hexane C6H14 (V-2) -4,034 835,4 - - -96 70 Toluene C7H8 (V-3) -5,878 1287 4,575 -4,,499 -40 315 n-heptane C7H16 (V-2) -4,325 1006 - - -90 100 Styrene C8H8 (V-3) -2,717 946,1 -3,1778 1,613 -30 360 Ethyl benzene C8H10 (V-3) -6,106 1363 5,112 -4,552 -40 340 n-octane C8H18 (V-2) -4,333 1091 - - -35 125


heat capacity (gas, liquid, solids) air, O2, N2, CO2, NH3, SO2 NaOH Benzene, glycerol, methanol, ethanol

thermal conductivity (gas, liquid, solids) Benzene, methanol, ethanol

Thermal conductivity of metals, isolation materials Metal temperature

[°C] thermal

conductivity [W.m-1.K-1]

Aluminium

0 202 100 206

Brass (70%Cu, 30%Zn)

0 97 100 104 400 116

Copper

0 388 100 378

Nickel

0 62 212 59

Cupro-nickel (10%Ni) 0 - 100 45 Monel 0 - 100 30 Stainless Steel (18%Cr, 8%Ni) 0 - 100 16 Carbon Steel

0 45 100 45 600 36

Titanium 0 - 100 16

Evaporation enthalpy


Saturated vapour pressure Antoine eq.: ln(p 0) = A − B / ( T + C ) where p 0 is saturated vapour pressure in kPa, T temperature in Kelvins, and A, B, C are empirical constants given in the table below. No. Formula Name A B C Tmin/K Tmax/K

Inorganic species 1 NH3 Ammonia 14,9331 2132,50 -32,98 179 261 2 Br Bromine 13,8291 2582,32 -51,56 259 354 3 HBr Hydrobromic acid 12,4537 1242,53 -47,86 184 221 4 Cl2 Chlorine 13,9460 1978,32 -27,01 172 264 5 HCl Hydrochloric acid 14,4890 1714,25 -14,45 137 200 6 SO3 Sulphur trioxide 18,8253 3995,70 -36,66 290 332 7 SO2 Sulphur dioxide 14,7530 2302,35 -35,97 195 280 8 CO2 Carbon dioxide 20,5748 3103,39 -0,16 154 204 9 H2O Water 16,2886 3816,44 -46,13 284 441

Organic species 10 CCl4 Carbon tetrachloride 13,8592 2808,19 -45,99 253 374 11 CHCl3 Chloroform 13,9582 2696,79 -46,16 260 370 12 CH2O2 Formic acid 14,9732 3599,58 -26,09 271 409 13 CH3Cl Methyl chloride 14,0902 2077,97 -29,55 180 266 14 CH4 Methane 13,2093 897,84 -7,16 93 120 15 CH4O Methanol 16,5725 3626,55 -34,29 257 364 16 C2H2 Acetylene 14,3331 1637,14 -19,77 194 202 17 C2H4 Ethylene 13,5218 1347,01 -18,15 120 182 18 C2H4O2 Acetic acid 14,7930 3405,57 -56,34 290 430 19 C4H8O Methyl ethyl ketone -7,71476 1,71061 -3,6877 -0,75169 255 20 C4H8O2 Ethyl acetate -7,68521 1,36511 -4,0898 -1,75342 289 21 C4H10 n-Butane -6,88709 1,15157 -1,99873 -3,13003 170 22 C4H10 Isobutane -6,95579 1,5009 -2,52717 -1,49776 165 23 C4H10O n-Butanol -8,00756 0,53783 -9,3424 6,68692 275 24 C4H10O Diethyl ether -7,29916 1,24828 -2,91931 -3,3674 250 25 C5H12 n-Pentane -7,28936 1,53679 -3,08367 -1,02456 195 26 C5H12O Amyl alcohol -8,97725 2,99791 -12,9596 8,84205 290 27 C6H5Cl Chloro benzene -7,58700 2,26551 -4,09418 0,17038 335 28 C6H6 Benzene -6,98723 1,33213 -2,62863 -3,33399 288 29 C6H6O Phenol -8,7555 2,92651 -6,31601 -1,36889 380 30 C6H7N Aniline -7,65517 0,85386 -2,51602 -5,96795 376 31 C6H12 Cyclohexane -6,96009 1,31328 -2,75683 -2,45491 293 32 C6H14 n-Hexane -7,46765 1,4421 -3,28222 -2,50941 220 33 C6H14O Diisopropyl ether -7,62613 1,29308 -2,90101 -6,14467 297 34 C7H8 Toluene -7,28607 1,38091 -2,83433 -2,79168 309 35 C7H16 n-Heptane -7,67468 1,37068 -3,53620 -3,20243 240 36 C8H8 Styrene -7,15981 1,78861 -5,10359 1,63749 303 37 C8H10 Ethyl benzene -7,48645 1,45488 -3,37538 -2,23048 330 38 C8H18 n-Octane -7,91211 1,38007 -3,80435 -4,50132 260


Vapour-liquid equilibria Symbols: x, y mol fractions in liquid or vapour respectively t(x) boiling temperature for mol based fraction in liquid x, y mass fractions in liquid or vapour respectively t(x) boiling temperature for mass based fraction in liquid

ethanol - n-butanol

x.x y t(x) y t(x) 0.00 0.0000 117.45 0.0000 117.45 0.01 0.0420 116.55 0.0421 116.02 0.03 0.1190 114.82 0.1196 113.39 0.05 0.1879 113.18 0.1891 111.03 0.10 0.3311 109.46 0.3337 106.08 0.15 0.4429 106.18 0.4459 102.12 0.20 0.5319 103.26 0.5348 98.87 0.25 0.6042 100.64 0.6065 96.16 0.30 0.6637 98.27 0.6654 93.84 0.35 0.7135 96.12 0.7145 91.84 0.40 0.7556 94.15 0.7561 90.09 0.45 0.7917 92.33 0.7918 88.53 0.50 0.8230 90.65 0.8227 87.14 0.55 0.8503 89.08 0.8499 85.89 0.60 0.8745 87.61 0.8739 84.76 0.65 0.8959 86.24 0.8954 83.72 0.70 0.9152 84.93 0.9147 82.77 0.75 0.9325 83.70 0.9321 81.89 0.80 0.9484 82.53 0.9481 81.07 0.85 0.9628 81.41 0.9626 80.31 0.90 0.9762 80.33 0.9761 79.60 0.95 0.9885 79.30 0.9885 78.93 0.97 0.9932 78.89 0.9932 78.67 0.99 0.9978 78.50 0.9978 78.42 1.00 1.0000 78.30 1.0000 78.30

heptane - octane

x.x y t(x) y t(x) 0.00 0.0000 125.60 0.0000 125.60 0.01 0.0232 125.12 0.0232 125.05 0.03 0.0678 124.17 0.0678 123.99 0.05 0.1101 123.26 0.1101 122.96 0.10 0.2068 121.09 0.2068 120.57 0.15 0.2926 119.06 0.2925 118.38 0.20 0.3693 117.16 0.3692 116.36 0.25 0.4382 115.37 0.4382 114.49 0.30 0.5006 113.67 0.5006 112.75 0.35 0.5574 112.05 0.5575 111.11 0.40 0.6094 110.52 0.6095 109.57 0.45 0.6571 109.05 0.6572 108.12 0.50 0.7010 107.63 0.7012 106.74 0.55 0.7416 106.28 0.7418 105.43 0.60 0.7792 104.97 0.7794 104.18 0.65 0.8141 103.71 0.8143 102.99 0.70 0.8466 102.49 0.8468 101.85 0.75 0.8768 101.31 0.8770 100.76 0.80 0.9050 100.17 0.9051 99.72 0.85 0.9313 99.06 0.9314 98.71 0.90 0.9558 97.99 0.9558 97.75 0.95 0.9787 96.94 0.9787 96.82 0.97 0.9874 96.54 0.9874 96.46 0.99 0.9959 96.13 0.9959 96.11 1.00 1.0000 95.93 1.0000 95.93


Methanol - Water

x.x y t(x) y t(x) 0.00 0.0000 100.00 0.0000 100.00 0.01 0.0763 98.07 0.0770 98.88 0.03 0.1948 94.84 0.1994 96.84 0.05 0.2822 92.25 0.2922 95.03 0.10 0.4257 87.52 0.4486 91.26 0.15 0.5144 84.28 0.5461 88.30 0.20 0.5767 81.84 0.6134 85.88 0.25 0.6247 79.90 0.6633 83.85 0.30 0.6640 78.26 0.7025 82.10 0.35 0.6979 76.83 0.7348 80.54 0.40 0.7282 75.54 0.7624 79.12 0.45 0.7558 74.36 0.7868 77.81 0.50 0.7817 73.26 0.8089 76.56 0.55 0.8062 72.23 0.8295 75.36 0.60 0.8296 71.25 0.8491 74.19 0.65 0.8523 70.31 0.8680 73.04 0.70 0.8744 69.40 0.8864 71.88 0.75 0.8960 68.53 0.9048 70.72 0.80 0.9173 67.68 0.9231 69.54 0.85 0.9382 66.85 0.9417 68.34 0.90 0.9590 66.05 0.9606 67.10 0.95 0.9796 65.27 0.9800 65.82 0.97 0.9878 64.96 0.9879 65.30 0.99 0.9959 64.65 0.9959 64.77 1.00 1.0000 64.50 1.0000 64.50

benzen-toluen

x,x y t(x) y t(x) 0.00 0.0000 110.61 0.0000 110.61 0.01 0.0228 110.15 0.0228 110.07 0.03 0.0669 109.25 0.0670 109.02 0.05 0.1091 108.36 0.1092 108.00 0.10 0.2066 106.23 0.2070 105.58 0.15 0.2942 104.20 0.2949 103.33 0.20 0.3731 102.27 0.3740 101.24 0.25 0.4443 100.42 0.4455 99.28 0.30 0.5088 98.66 0.5101 97.44 0.35 0.5673 96.97 0.5687 95.72 0.40 0.6205 95.35 0.6219 94.09 0.45 0.6690 93.79 0.6704 92.56 0.50 0.7134 92.30 0.7146 91.11 0.55 0.7539 90.86 0.7550 89.74 0.60 0.7911 89.48 0.7920 88.45 0.65 0.8252 88.16 0.8260 87.22 0.70 0.8566 86.88 0.8572 86.05 0.75 0.8855 85.64 0.8859 84.93 0.80 0.9122 84.46 0.9124 83.88 0.85 0.9367 83.31 0.9369 82.87 0.90 0.9595 82.20 0.9595 81.90 0.95 0.9805 81.13 0.9805 80.98 0.97 0.9885 80.72 0.9885 80.62 0.99 0.9962 80.31 0.9962 80.27 1.00 1.0000 80.10 1.0000 80.10


Liquid-liquid equilibria data expressed in relative weight fractions of acetone: Water – Acetone – Toluene Water – Acetone - o-Xylene

aqueous phase organic phase aqueous phase organic phase 0.0059 0.0036 0.0092 0.0060 0.0175 0.0112 0.0183 0.0120 0.0277 0.0188 0.0370 0.0236 0.0354 0.0251 0.0547 0.0382 0.0438 0.0325 0.0865 0.0660 0.0553 0.0426 0.0989 0.0735 0.0652 0.0530 0.1891 0.1583 0.0782 0.0636 0.2821 0.2508 0.0883 0.0727 0.1038 0.0883


Integral enthalpy of dissolution at 25°C, in kJ.kg-1 w

0 0.01 0.02 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

NaOH -1072 -1055 -1055 -1065 -1071 -1070 -1060 -999 -954 -871 -762 -670 -608 KOH -985 -974 -969 -968 -964 -958 -947 -932 -912 -882 -844 -806 -754 KCl 231 NaCl 66.6 73 72 65.5 55 45.3 37 32.5 NH4Cl 275 285 286 286 286 284 284 282 281 CaCl2 -748 -729 -727 -719 -711 -704 KNO3 121 119 NH4NO3 322

Increase of boiling point in solutions of electrolytes

w [-]

0.0 0.1 0.2 0.3 0.4

∆ Tbo

il [K]

0

5

10

15

20

25

NaNO3

NaOHKOHNH4ClMgCl2NaClCaCl2Na2CO3

Seminars Unit Operations I

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Transcript of Seminars Unit Operations I