R Lab 1 (3).docx

Sohar University Faculty of engineering Chemical engineering Reaction engineering CHEM4005

Lab experiment 1: Batch reactor Names: Atheer Hamed AL-Saadi Eman Ali AL-Shehhi Shima Yousef AL-Baloshi Zakia Abdullah AL-Houssani Monueera Saeed AL-Moqbali

ID: 140093 140030 140237 150395 130826

Objective: The aim of these experiment is to determine the value of reaction rate constant (k) with different surrounding temperature and calculate the activation energy (Ea) of reaction.

Introduction: Reactor is one of the important units in chemical industry, it is the place for the reaction took place. There are many types of reactor. One of the example reactors is tubular reactor. In tubular reactor continuous, sometimes called PFR as shown in fig(1) , contain one or more fluid reagents are pumped through a pipe or tube. The chemical reaction proceeds as the reagents travel through the PFR. In this type of reactor, the changing reaction rate creates a gradient with respect to distance traversed; at the inlet to the PFR the rate is very high, but as the concentrations of the reagents decrease and the concentration of the product (s) increases the reaction rate slows.[1] With a constant flow rate, the conditions at any one point remain constant with time and changes in time of the reaction are measured in terms of the position along the length of the tube. The reaction rate is faster at the pipe inlet because the concentration of reactants is at its highest and the reaction rate reduces as the reactants flow through the pipe due to the decrease in concentration of the reactant. [2] In the tubular reactor, the reactants are continually consumed as they flow down the length of the reactor. Applications, tubular reactors have a wide variety of applications in either gas or liquid phase systems. Common industrial uses of tubular reactors are in gasoline production, oil cracking, synthesis of ammonia from its elements, and the oxidation of sulfur dioxide to sulfur trioxide. Also it is used in the steam cracking of ethane, propane and butane and naphtha to produce alkenes. [3]

Fig (1)

Theory:  to calculate the percentage of Conversion: [𝐴]0 − [𝐴] 𝑋𝑎 = ∗ 100 [𝐴]0 Where: 𝑋𝑎 :percentage of Conversion of NaOH [𝐴]0 : initial concentration of NaOH (

𝑚𝑜𝑙𝑒 𝑐𝑚3

)

[𝐴]: concentration of NaOH in discharge (

𝑚𝑜𝑙𝑒 𝑐𝑚3

)

 To calculate the contestant reaction rate there are many method but in our experiment it determined according to flow system: 𝐹𝑁𝑎𝑂𝐻 + 𝐹𝐶𝐻3 𝐶𝑂𝑂𝐶2𝐻5 𝑥𝐴 𝑘=( ) )∗( 𝑉 ∗ [𝐴]0 1 − 𝑥𝐴 Where: FNaOH: flow rate of NaOH (

𝑐𝑚3 𝑚𝑖𝑛

) 𝑐𝑚3

𝐹𝐶𝐻3 𝐶𝑂𝑂𝐶2 𝐻5 : flow rate of ethyl acetate (

𝑚𝑖𝑛

V: the volume of the tubular reactor cm3 𝜋𝑟𝐷2

 Where 𝑉 = ∗ 𝐿: 4 D: the diameter of reactor (cm) L:length of tubular reactor (cm) K: reaction rate constant (

𝑐𝑚3

𝑚𝑜𝑙∗𝑚𝑖𝑛

)

)

Procedure: 1. Prepare all the materials and equipment’s required for the lab experiment. 2. To prepare a solution of 0.1 M of NaOH measure 2g of NaOH by using the balance and then add NaOH to 500ml of distillated water and mix it to make sure that all NaOH is dissolved in water. 3. To prepare ethyl acetate with concentration 0.1M put 4.89ml of ethyl acetate in Florence flask then add distillated water until the volume reach 500ml. 4. Fill the vessel by water to a level above the overflow ,then switch on the hot water circulation .(the temperature of the water in the reactor vessel will begin to rise and will be automatically maintained at the desired set point (25c˚). 5. switch on feed pumps and computer . the reactant ( NaoH and ethyl acetate)will flow from feed vessel and enter the reactor through the connections in the lid, each reactant passes through pre-heat coils submerged in the water in which they are individually brought up to the reaction temperature . At the base of the tubular reactor coil the reactant are mixed together in a “T” connection and begin to pass through coil. The reacting solution will emerge from the coil through connector in the lid where a probe senses continuously the conductivity which is related to degree of conversion. 6. collect the data from pc(computer).

Observation and Calculation: Observation: Elapsed Hydroxide Acetate Hydroxide Acetate Measured Temp Sodium Time concentration concentration Flowrate Flowrate Conductivity of Hydroxide min in tank in tank Fa Fb Reactor Feed [mol/dm³] [mol/dm³] [cm³/min] [cm³/min] [mS] Conc. [°C] [mol/dm³] 0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45

0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100

0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100 0.100

80.2 80.3 80.3 80.2 80.3 80.3 80.3 80.2 80.0 80.3 80.3 80.4 80.2 80.3 80.2 80.3

80.4 80.4 80.6 80.5 80.5 80.5 80.6 80.5 80.4 80.5 80.4 80.6 80.5 80.6 80.5 80.4

Table (2)

7.686 6.641 6.846 6.865 6.855 6.846 6.855 6.865 6.865 6.865 6.377 7.061 7.070 7.090 7.031 7.041

25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0 25.0

0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050

Ethyl Acetate Feed Conc. [mol/dm³]

Calculated Initial Conductivity [mS]

0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050

10.455 10.457 10.449 10.452 10.452 10.455 10.447 10.449 10.441 10.455 10.462 10.455 10.452 10.447 10.449 10.457

Elapsed Time min

Calculated Final Acetate Concentration [dm/m³]

Calculated Final Conductivity [mS]

Current Sodium Hydroxide Concentration [mol/dm³]

Current Sodium Acetate Concentration [mol/dm³]

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45

0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050

3.842 3.843 3.840 3.841 3.841 3.842 3.840 3.840 3.838 3.842 3.845 3.842 3.841 3.840 3.840 3.843

0.02902500 0.02112606 0.02269654 0.02283688 0.02276310 0.02268212 0.02277754 0.02284413 0.02286594 0.02282963 0.01912022 0.02430467 0.02438571 0.02454761 0.02409795 0.02414997

0.0209126677 0.0288241187 0.0272163704 0.0270883858 0.0271621987 0.0272556134 0.0271229067 0.0270686565 0.0270093111 0.0271081053 0.0308548678 0.0256331225 0.0255395510 0.0253528881 0.0258148378 0.0258002030

Table (2) [completed]

Reactor parameter Internal diameter Length of tube Table (3)

5 mm 20.9 cm

Calculation: Elapsed Time min

Conversion of Sodium Hydroxide (%)

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45

42% 58% 55% 54% 54% 55% 54% 54% 54% 54% 62% 51% 51% 51% 52% 52%

Calculated Specific Rate Constant K 3 ( dm /mol*min ) 3.30 4.55 4.31 4.28 4.29 4.30 4.29 4.28 4.27 4.28 4.87 4.05 4.03 4.01 4.08 4.07

Volume ( cm3)

4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404 4.103705404

Table (4)

conductivity vs concentration 9.000

conductivity (mS)

8.000 7.000 6.000 5.000 4.000 3.000 2.000 1.000 0.000 0.00000

0.00500

0.01000

0.01500

0.02000

NaOH concentration

0.02500

(mol/dm3)

0.03000

0.03500

Sample calculation: Mass of NaOH was calculated as:

M= 0.1

n

volume

mol mole = l 0.5 L

n = 0.1

mol ∗ 0.5 l = 0.05 mol l

m = Mw ∗ n = (22.990 + 16 + 1)

g mol

∗ 0.05 mol = 2 g

The volume of CH3COOC2H5 (L) was calculated as:

𝑛 𝑉 𝑛 =𝑀∗𝑉 𝑔 𝑛 = 0.1 ∗ 0.5 𝑙 = 0.05 𝑚𝑜𝑙 𝑀=

𝑙

𝑚 = 𝑛 ∗ 𝑀𝑤 = 0.05 𝑚𝑜𝑙 ∗ 88.11 𝑉=

𝑚 4.41𝑔 = 𝑔 = 4.9 𝑚𝑙 𝜌 0.9 𝑚𝑜𝑙

𝑔 = 4.41𝑔 𝑚𝑜𝑙

The volume of tubular reactor : 1𝑐𝑚 2 (5 𝑚𝑚 ∗ 10𝑚𝑚) πD V= ∗𝐿 =𝜋∗ ∗ 20.9 𝑐𝑚 = 4.103705404 𝑐𝑚3 4 4 2

The conversion at t=3min 𝑚𝑜𝑙 (0.05 − 0.02112606) [𝐴]0 − [𝐴] 𝑑𝑚3 ∗ 100% = 58% 𝑋𝑎 = ∗ 100 = 𝑚𝑜𝑙 [𝐴]0 0.05 𝑑𝑚3 Calculate the reaction rate constant (k) at t=3min: 𝑘=(

𝐹𝑁𝑎𝑂𝐻 + 𝐹𝐶𝐻3 𝐶𝑂𝑂𝐶2𝐻5 𝑥𝐴 )∗( ) 𝑉 ∗ [𝐴]0 1 − 𝑥𝐴 𝑐𝑚3 (80.3 + 80.4) 𝑚𝑖𝑛𝑡 =

0.58 𝑑𝑚3 ∗ = 4.55 𝑚𝑜𝑙 1 − 0.58 𝑚𝑜𝑙 ∗ 𝑚𝑖𝑛𝑡 3 4.103705404 𝑐𝑚 ∗ 0.05 3 𝑑𝑚

Dissection and analysis: In these experiment we used batch reactor where there is no flow in and flow out. The following reaction: 𝑵𝒂𝑶𝑯 + 𝑪𝑯𝟑 𝑪𝑶𝑶𝑪𝟐 𝑯𝟓 → 𝑪𝑯𝟑 𝑪𝑶𝑶𝑵𝒂 + 𝑪𝟐 𝑯𝟓 𝑶𝑯 This reaction is exothermic, so we use Sheller to cool the heat which is produced by the reaction. As we can see from table (2) and (3) the concentration of NaOH (a1) was decreased (consumed) during the time where the conversion is increased. In addition, the order of reaction is second order because when plotted the data according to each order (zero, first and second) as graph (1), (2), (3), (4), (5) and (6) are showed. We found graph (3) and (6) is only becomes linearity which means the order of this reaction is second order. Moreover, we observe that the reaction rate constant is depend on temperature as we see reaction rate constant k value change with temperature as we see in table (6) and graph(3) and (6). These prove the Arrhenius law that the reaction rate constant increase exponentially with decreasing temperature as we see in blow equation: −𝑬𝒂

𝒌 = 𝑨 ∗ 𝒆 𝑹𝑻

Also, the activation energy ( Ea) for this reaction is -80.537 minimum energy required to start reaction is 80.537

𝑘𝐽 𝑚𝑜𝑙

𝑘𝐽 𝑚𝑜𝑙

which mean the

and the activation energy

becomes ( - ) because the is exothermic . It remains constant because we doesn’t change the reaction or add catalyst. Finally, the experiment accuracy wasn’t 100% for many reasons. One of these reasons the temperature of surround of system of reaction wasn’t 20 exactly because it may loss or gain heat from room area. Also it may fault in device itself.

Conclusion: To sum up, we conclude from this experiment that the order of below reaction is second order and the value of reaction rate constant (K) affected by change of temperature of surrounding for reaction system where it is increase exponentially with decreasing temperature as the data in table (6) is proved that. Also the activation energy is constant and it becomes (-) due to exothermic reaction but it may change when change reaction or add catalyst.

References: 1. Unknown. (n.d).corrosionpedia. Batch reactor .1/10/2018. Retrieved from: https://www.corrosionpedia.com/definition/4820/batch-reactor 2. Unknown.(n.d). Wikipedia. Batch reactor. 1/10/2018. Retrieved from:

https://en.wikipedia.org/wiki/Batch_reactor 3. Fig (1): indiamart. Isothermal batch reactor . 1/10/2018. Retrieved from:

https://www.indiamart.com/proddetail/isothermal-batchreactor-4699667448.html 4. Fig (2): Wikipedia. Batch reactor. 1/10/2018. Retrieved from:

https://commons.wikimedia.org/wiki/File:Batch_reactor.2.jpg