Chapter 1

Troubleshooting of Malfunctioned PLC Controlled Rectification Pilot Plant

Chapter 1Introduction

Chapter 1Introduction

QVF Bubble Cap Distillation Unit DN50It is developed primarily for teaching, training & research purposes. It is used for the separation of mixtures at atmospheric pressure in a continuous operation. The unit has the following special features, which are of particular value in training situations: Direct heat input into the reboiler by natural circulation evaporation using one electrical cartridge heaters made of stainless steel. Silver coated & vacuum jacketed bubble cap column minimizes heat loss to the surroundings. Sampling on each trays & on the bottom & top product to determine the practical separation behavior of the particular mixture.The method of operation of a bubble cap distillation column for the separation of liquid mixtures can be described in the following terms: the vapor mixture rises from the reboiler, passes over the column trays & is fully condensed in the condenser. The condensate runs down the column counter-current to the vapor through the trays back into the reboiler at each trays the rising vapor attempts to achieve the equilibrium with the liquid condensate, thus effecting both mass & heat transfer. In the ideal case, the rising vapor should be in equilibrium with the liquid but in actual columns complete exchange does not always take place.The efficiency of a bubble cap distillation column can be evaluated using the number of theoretical plates required to achieve the same separation as the actual column. As the purity of a distillate is dependent to a very large extent on the number of theoretical plates, determination of the number of theoretical plates in the column is very important in the design of a distillation unit.

General DescriptionAll glass components of the QVF Bubble Cap distillation Unit are made of borosilicate 3.3 glass with caps PTFE gas kits. Process flow diagram is available on next page.1. Reboiler (B2) Circular evaporator equipped with one 3kW electrical heater made of stainless steel (W1).2. Bubble Cap Column (K1+K2) a DN50 Bubble Cap Column each with five plates, silver coated & vacuum jacketed.3. Top Condenser (W3) a high efficiency condenser with 0.3m2 exchange area & cooling water connections.4. Distillate Coolers (W4) having 0.05m2 exchange area & cooling water connections.5. Bottom Product Cooler (W5) having 0.1m2 exchange area & cooling water connections.6. Distillate Measuring Vessels (B3) 0.25 liter graduated vessel.7. Bottom Product Measuring Vessel (B5) 0.25 liter graduated vessel8. Distillate & Bottom Product Sample Vessel (B4, B6) round bottom flask 100ml9. Feed & collecting Vessel (B7) 10L vessel10. Feed Pump (P1) 240 ml/min capacity gear11. Feed preheater (W2) a 600 W electrical heated hose DN16 with temperature control, length 2.5meter.12. Vacuum Pump (P2) diaphragm pump 24V, with 1.6m3/hrexhausation rate.13. Cooling Trap (W6) A=0.04m2

Instrumentation & Control1. Temperaturea) Reboiler Temperature (TIR 1)b) Tray Temperature (TIR 2 until TIP 11)c) Distillate Temperature (TIR 12)d) Feed Temperature Control (TIR 13)e) Cooling water temperature Entry / Exit (TIR 14, TIR 15)

2. Flow Ratea) Feed flow rate control (FIRCA 1)b) Flow rate cooling water (FIRSA 2)

3. Pressurea) Column pressure difference (DPIRC 1)b) Top condenser control (PIRC 2)

4. Levela) Reboiler Level Switch (LRS-A-)

5. Refluxa) Timer based reflux controller (KS-1)

4Troubleshooting of Malfunctioned Rectification Pilot Plant