TECHNOLOGICAL INSTITUTE OF THE PHILIPPINES363 P. CASAL ST., QUIAPO, MANILACOLLEGE OF ENGINEERING AND ARCHITECTURECHEMICAL ENGINEERING DEPARTMENT

EXPERIMENT NO. 4: BATCH REACTOR

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JANUARY 14, 2015EXPERIMENT NO. 4BATCH REACTOR

Discussion:

The Batch reactor is the generic term for a type of vessel widely used in the process industries. In a batch reactor the reactants and the catalyst are placed in the reactor and the reaction is allowed to proceed for a given time whereupon the mixture of unreacted material together with the products is withdrawn. Provision for mixing may be required. In an ideal batch reactor, the concentration and temperature are assumed to be spatially uniform. In practice, the condition can be approximately realized by vigorous agitation or stirring..All the elements of the fluid spend the same amount of time in the reactor, and hence have the same residence time. From the viewpoint of thermodynamics, a batch reactor represents a closed system. The steady states of the batch reactor correspond to states of reaction equilibria.

Batch reactors are also used when only a small amount of product is desired. For this reason batch reactors are favored when a process is still in the testing phase, or when the desired product is expensive. Batch reactors are used in the pharmaceutical industry, which requires consistent, high quality results. One batch reactor may also be used to make a variety of products at different times.

A typical batch reactor consists of a tank with an agitator and integral heating/cooling system. Liquids and solids are usually charged via connections in the top cover of the reactor. Vapors and gases also discharge through connections in the top. Liquids are usually discharged out of the bottom.

ADVANTAGESDISADVANTAGES

High conversions can be obtained by leaving reactants in reactor for extended periods of time. Batch reactor jackets allow the system to change heating or cooling power at constant jacket heat flux. Versatile, can be used to make many products consecutively. Good for producing small amounts of products while still in testing phase. Easy to clean. High cost of labor per unit of production. Difficult to maintain large scale production. Long downtime for cleaning leads to periods of no production.

Materials:

Reactor pH meter 0.05 M Sodium Hydroxide 0.05 M Ethyl Acetate

Procedure:

1. Prepare equimolar amount of sodium hydroxide and ethyl acetate.2. Set the temperature to 30C.3. Pour the reactants into the reactor.4. Stir and after 5 minutes, obtain a sample at least 10 mL or enough to determine the concentration with respect to time.5. Compute for the concentration of sodium hydroxide at t = 5 min.6. Compute the conversion of the reactant, NaOH per sampling time.7. Assume the order and plot the concentration versus time relation.8. If straight line I plot, determine the rate constant from the slope. Otherwise, make another assumption of the order.9. Express the batch reactor design equation in terms of conversion and plot the conversion versus time.

Experminental Set-Up:

Data and Results:

Time, minpH[NaOH], mol/LConversion, Xa

511.078.51x10-120.562867215

1011.433.72x10-12-0.174731183

1511.364.37x10-12-0.173913043

2011.295.13x10-12-0.202729045

2511.216.17x10-12-0.200972447

3011.137.41x10-12-0.148448043

3511.018.51x10-12-0.096357227

4011.039.33x10-11-0.093247588

4510.991.02x10-11-0.068627451

5010.961.09x10-11-0.055045872

5510.941.15x10-11-0.12173913

pH, CaoCaopH, CaCa

11.078.51x10-1211.433.72x10-12

11.433.72x10-1211.364.37x10-12

11.364.37x10-1211.295.13x10-12

11.295.13x10-1211.216.17x10-12

11.216.17x10-1211.137.41x10-12

11.137.41x10-1211.018.51x10-12

11.018.51x10-1211.039.33x10-12

11.039.33x10-1110.991.02x10-11

10.991.02x10-1110.961.09x10-11

10.961.09x10-1110.941.15x10-11

10.941.15x10-1110.891.29x10-11

Analysis and Interpretation of Data

Determining the order of reaction and the reaction constant of sodium hydroxide is the main objective of this experiment. The pH of the samples were determined using pH meter and the fromula used for calculating the concentration of sodium hydroxide was,

the calculated will then serve as the initial concentration for the next sample.

Assuming that the reaction is in first order and using the data gathered,

Reaction Order: 1stReaction Rate Constant: 0.0247

Conclusions and Recommendations:

In conclusion, the concentration of the sample was directly proportional to the time. First order reactions depends on the concentration of only one reaction. In this experiment, sodium hydroxide was the reactant with the first order; the other reactant was in zero order.

It is recommended that the instructions to use the reactor be clearly stated as it causes misunderstanding which in turn causes error in handling the reactor. It is also recommended that the reactor be thouroughlt cleaned as dusts and rusts can affect the results obtained.