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TITLE: THE EFFICIENCY OF ETHYLENE GLYCOL - WATER SEPARATION IN ASHORT PATH DISTILLATION.1 INTRODUCTION1 EXPERIMENTAL BACKGROUNDShort path distillation is known as a thermal separation process especially for thermal sensitive products. The short path distillation technique is normally done in reduced...

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TITLE: THE EFFICIENCY OF ETHYLENE GLYCOL - WATER SEPARATION IN A SHORT PATH DISTILLATION.

1.0 INTRODUCTION

1.1

EXPERIMENTAL BACKGROUND

Short path distillation is known as a thermal separation process especially for thermal sensitive products. The short path distillation technique is normally done in reduced pressure and it involves the distillate travel in a short distance. The two things that cause a minimum thermal stress to the distilled product is that the short residence time and another one is low evaporation temperature .Short path distillation is a type of continuous separation process which is working under vacuum conditions. The considerably lower pressure present in the short path evaporator is obtained by the short distance for the vapors on their way from the evaporator surface to the condenser. There is only a minor pressure drop between the evaporator and the condenser due to the cross section area of flow is equal to the evaporator surface. Normally we use this short path distillation technique for the compounds that are unstable at high temperatures or we also use this technique to purify small amounts of compound. By reducing the operating pressure, a decrease of boiling temperatures is obtained in a short path distillation experiment. In this case, during the experiment ethylene glycol - water is well mixed with a ratio of 1:1 in a beaker and stirred until we obtain a homogeneous solution. First thing is first switched on the main power supply control panel. Then the thermostat, chiller and vacuum pump pressure are set at certain value respectively. We know that the equipment is ready for the experiment by referring to the chiller temperature and thermostat temperature. We set 5 minutes interval to run for every set of experiment. The volume of distillate and concentrate are recorded after every 5 minutes interval. The experiment is then repeated with different operating parameters as in results and discussion. If the temperature becomes higher the separation efficiency also become higher as the boiling can be achieved faster in high temperature where more heat energy is supply. In overall, we can say that the separation efficiency of ethylene glycol and water is directly proportional to the temperature.

1.2 SCOPE OF THE EXPERIMENT

1.2.1 To determine the efficiency of ethylene glycol - water separation in a short path distillation.

1.3 OBJECTIVE

1.3.1 To determine the temperature on the thermal separation efficiency of ethylene glycol and water using short path distillation.

1.3.2 To study the relationship between the temperatures and the separation efficiency with the stirrer speed set at constant speed.

1.4 LITERATURE REVIEW

Distillation is a process which a liquid and gas blend of at least two substances is isolated into its segment portions of wanted virtue, by application and expulsion of heat. In distillation process, the heating process from liquid phase into vapour phase, then cooling the vapour into liquid by condensation process. It is especially appropriate for high purity division since any level of detachment can be acquired with fixed energy consumption by expanding the quantity of equilibrium stage (J. Halvorsen, S. Skogestad, 2000).

There are several component of distillation column mixture that are separated by manipulating the vapour and liquid equilibrium. By contacting the vapour from lower part to the liquid from the upper part, where the vapour enriched the more volatile component and liquid will be less (J. Pla-Franco, 2019). According to Raoult’s law (Kevin de berg, 2011), where the present of the component in both phase which liquid-vapour equilibrium can describe through the equation below:

yip = XiPis(T)

Where yi is the mole fraction of the component in vapour phase, X i is the mole fraction of the component in liquid phase, p is the total pressure and P is is the vapour pressure while T is the temperature dependent (Kevin de Berg, 2011). There are several types of distillation where the new type of distillation is short path distillation that is more effective compared to other

type of distillation. Short path distillation is the time saving and cost effective in order to purify a mixture under the vacuum pressure that is faster than the other distillation process.

First of all ethylene glycols or H(OCH2CH2)nOH form a homologous series all the members of which decompose at their critical points. A phase diagram at which both the liquid phase and gas phase of a substance have the same density we call it as a critical point. According to E.D.Nikitin et.al.(1993), we can determine the critical temperatures and pressures of mono-,di-,tri- and tetra ethylene glycols and polyethylene glycols PEG(300), PEG(400) and PEG(600) were measured using the pulse-heating technique which is applicable to thermally unstable compounds. As we know ethylene glycol is a sweet, clear and slightly viscous liquid that has a boiling point of 198°C.The common use of ethylene glycerol is as automotive antifreeze. Ethylene glycol and water solution with a ratio of 1:1 boils at 129°C and freezes at -37°C. It is serving as an excellent coolant in automotive radiators. The boiling point of ethylene glycol after mixing with the water equally become lesser. The phase diagram of water is more important in order for the designing process with water and to understand the behaviour of water in its various states. Water can exist at three phase as solid, liquid and gas. Gaseous and liquid water coexist in equilibrium along the vapor pressure curve at higher temperatures. According to Y.Marcus (2012) the triple point where the solid phase, liquid phase and gaseous phase water coexist in equilibrium and it has been defined to occur at 273.16K and 611.657Pa. Sublimation is the phase transition between solid water which is ice and gaseous water below the triple point. A.H.Harvey, D.G.Friend (2004) also state that at higher pressures, ice melts at lower temperatures than at ambient pressure, a thermodynamic consequence of the lower density of ice compared to that of liquid water.

Figure 1: Phase diagram of water as a function of temperature and pressure

2.0

METHODOLOGY

2.1 EQUIPMENT AND MATERIALS Equipment: Short path distillation unit Materials: Ethylene glycol and water

2.2 EXPERIMENT PROCEDURE Start-up procedure 1. The cold trap is ensuring to be filled with ice. 2. The main power supply at control panel is switch on. 3. The thermostat, cooler and vacuum pump pressure are set at 70 oC, 12oC and 250 mbar, respectively. 4. All the valves are close to create vacuum pressure. 5. Once the chiller and thermostat temperature have reached the set point, the equipment is ready. Process Behaviour 1. Prepare the solution of ethylene glycol and water with a ratio of 1:1 in a beaker and stir it homogenously. 2. Turn on the stirrer. 3. Feed in the solution. 4. Open the valve. 5. Record the stopwatch for 10 ml, 20ml, 30ml, 40ml, 50ml. Shut down procedure 1. 2. 3. 4. 5.

Set the thermostat at room temperature. Let it cool down by itself. Open the valve to release pressure. Turn off stirrer, cooler and vacuum pump. Once it reaching room temperature, turn off the main supply power.

3.0 EXPERIMENTAL PLANNING ● Variables I. II. III.

Controlled Variable: The stirrer speed and the vacuum pressure. Manipulated Variable: Set point of the temperature. Responding Variable: Separation Efficiency.

● Outline for team plan 12/2/2020-There was a lab briefing on how the proposal should be done. 14/2/2020-Meeting among our group mates were conducted to discuss about the proposal and individual tasks were distributed. 16/2/2020-Information gathered by each individual were shared among one another. 20/2/2020-Lab proposal was compiled and turned into Turnitin. 21/2/2020-Proposal submission. ● The task delegation among the team members before, during and after the experiment. Before conducting the experiment, we have to complete the proposal first. The task for the proposal was delegated among the team members by referring to the outline of proposal provided in the lab module. We divide the proposal into five particular parts which are: BEFORE EXPERIMENT: I. Introduction by Shanthi A/P Sounthararajan II. Literature Review by NorsyahirahNafisyah Abdul Rajak III. Materials and Method by Ahmad Syafi Bin Salihin IV. Experimental Plan by Yashuivinijee A/P K. Maniendaran V. Anticipated Results & Discussion by Chong Zi Ern DURING EXPERIMENT: I. II. VI.

Explaining the Instructions and Procedures: Ahmad Syafi Bin Salihin. Handling the Equipments: Chong Zi Ern & Shanthi A/P Sounthararajan. Recording the data: NorsyahirahNafisyah Abdul Rajak &Yashuivinijee A/P K. Maniendaran.

● Then, before submit the proposal, one person will compile and print out the proposal. During the experiment, the tasks such as handling the equipment, observing the graph and jotting down the data will be divided equally. Everyone will take place in conducting the experiment. After the experiment, all team members will involve in sharing the information, discussion and doing the lab report (individually).

4.0 ANTICIPATED RESULTS The result of the experiment is to find the separation efficiency of ethylene glycol-water separation in a short path distillation unit by manipulating the evaporator temperature. The stirrer speed kept constant throughout the whole experiment. Stirrer speed (rpm)

50

Feed flow rate (L/min) Vacuum pressure (bar) Contact time (min)

5

Ethylene glycol-water ratio

1:1

Table 1a: Conditions of equipment Temperature ( ᶱC)

Distillate volume (L)

Concentrate volume (L)

Separation efficieny (%)

70

72

74

76

78 Table 1b: Result of experiment

No.

Temperature ( ᶱC)

1

70

2

72

3

74

4

76

5

78

Distillate (L)

Concentrate (L)

Table 1c: Calculate the feed flow rate (L/min)

Flow rate (L/min)

EXPECTED GRAPHS

Separation Efficiency (%)

Figure 2: Concentrate volume vs temperature

Temperature (℃)

Figure 3: Separation efficiency vs temperature

5.0 DISCUSSION The short path distillation unit has been completely assembly and commissioned in Unit Operation lab in this experiment. The main function of short path distillation unit is to get the desired product with high purification. It is a perfect distillation system with fast reaction and it can save working time and cost of experiment. The short path distillation does not require additional solvents to catalyze the distillation process. In this experiment, we need to investigate the separation efficiency of ethylene glycol-water in different evaporator temperature. Based on the experiment that is going to be conducted, it can be assumed that the evaporator temperature with affect the separation efficiency of ethylene glycol with water. The expected graph of concentrate volume versus temperature will show directly proportional trend for the concentrate volume increases as the temperature increases. The expected graph of separation efficiency versus temperature should follow the trend of increasing separation efficiency as the evaporator temperature increases. At higher temperature, the kinetic energy of particles increases and collides vigorously between the reactant particles. (Moller et al.,2002). Thus, the collision between particles increases the contact area of particles and further increases the separation efficiency.

6.0 APPENDICES

CALCULATION Separation efficiency = Flow rate =

concentrate volume × 100 % feed volume

Distillate volume +Concentrate volume 5

Average flow rate =

flow rate 1+Flow rate 2+ Flow rate3+ Flow rate 4+ Flow rate5 5

7.0 REFERENCES 1) A.H. Harvey, D.G. Friend.(2004).Physical properties of water : aqueous systems at elevated temperatures and pressures, Chapter 1.

2)

E.D.Nikitin et al.(1993)Ethylene glycol performance. Ethylene Glycol Products.

3)

J.Halvoren and S.Skogestad.(2000).Theory of distillation. Journal article.

4)

Jordi Pla-Franco et.al (2019).Azeotropic distillation for 1-propanol dehydration with

diisoprpyl ether as entrainer:Equilibrium data and process. Journal of Separation and Purification technology. Volume 212. Pg 692-698.

5)

Kevin de berg.(2011). Raoult`s law :A reinterpretation for concentrated strong 1:1

Electrolyte solution. Science and mathematics papers and Journal article. Paper 31

6) H.B Moller, S.G. Sommer, B.K. Ahring. (2002). Separation efficiency and particle size distribution in relation to manure type and storage conditions. Bioresource Technology,85(2). Retrieved from https://www.sciencedirect.com/science/article/pii/S0960852402000470?via%3Dihub

7) Y.Marcus.(2012).Supercritical Water. A green solvent: Properties and uses. Journal article....