QUESTION 1

In a Spun Pile production plant, three (3) boilers with different designs capacity were used for the drying process as shown in Figure 1. Demonstrate how you optimize the boiler load to meet the steam demand of 210 t/h at minimum energy consumption.

The existing boiler operation data is shown in Table 1. Figure 1: Boiler Load Capacity Table 1: Boiler Operation Data BOILER 1 BOILER 2 BOILER 3 Steam Generation (Ton/Hr) Energy Consumption (W/Hr) Steam Generation (Ton/Hr) Energy Consumption (W/Hr) Steam Generation (Ton/Hr) Energy Consumption (W/Hr) 36 3000 54 4122 63 4565 42 3360 63 4667 74 5104 48 3693 72 5143 84 5600 54 4000 81 5704 95 6097 60 4286 90 6165 105 6563

QUESTION 2

Vinyl acetate monomer ‘‘VAM’’ is manufactured by reacting acetic acid with oxygen and ethylene according to the following chemical reaction: 2 4 2 2 4 C H 0.5 O C H O2 C4H6O2 H2O Consider the process shown in Figure 2. A fresh feed of 10,000 kg/h of acetic acid ‘‘AA’’ along with 200 kg/h of water are evaporated in an acid tower.

The vapour is fed with oxygen and ethylene to the reactor where 7000 kg/h of acetic acid are reacted and 10,000 kg/h of Boiler 1 Capacity 60 t/h Boiler 1 Capacity 90 t/h Boiler 1 Capacity 105 t/h 210 t/h demand VAM are formed. The reactor off-gas is cooled and fed to the first absorber where AA (5100 kg/h) is used as a solvent. Almost all the gases leave from the top of the first absorption column together with 1200 kg/h of AA.

This stream is fed to the second absorption column where water (200 kg/h) is used to scrub acetic acid. The bottom product of the first absorption column is fed to the primary distillation tower where VAM is recovered as a top product (10,000 kg/h) along with 200 kg/h of water and a small amount of AA (100 kg/h) which is not economically justifiable to recover. This stream is sent to final finishing.

The bottom product of the primary tower (6800 kg/h of AA and 2300 kg/h of water) is mixed with the bottom product of the second absorption column (1200 kg/h of AA and 200 kg/h of water). The mixed waste is fed to a neutralization system followed by biotreatment.

In this question, let consider the case when no changes are made to the consumption by chemical reaction and there are no adjustments in design or operating conditions to reduce fresh AA consumption. Evaluate the minimum fresh usage and minimum terminal losses of AA.

Figure 2: VAM Production Process Based on the technical description given, kindly execute the following tasks

Task 1: Evaluate the minimum fresh usage and minimum terminal losses of identified compound by using the mass integration approach. (10 Marks)

Task 2: Evaluate the influence of the fresh usage and terminal losses of indentified compound on the economic perspective (You may use any reliable resources from the Website to estimate the overall production cost) (10 Marks)