DISTILLATION COLUMNWITH LEVEL AS VARIABLE

Name ID Num

LAW CHOON CHUAN EC10103

NATASHA EMLYN ANAK DADI EC10002

WAN NUR AF'ZAM BINTI WAN ABD RAZAB EC10095

CHAN HWEE GEEM EC10047

TEOH SHIN YEE EA10051

INTRODUCTION

• Distillation is a process that separates two or more components into an overhead distillate and a bottoms product. The bottoms product is almost exclusively liquid, while the distillate may be liquid or a vapor or both.

• The separation process requires three things.1) second phase must be formed so that both liquid and vapour phases are present and can contact each other on each stage within a separation column. 2) components have different volatilities so that they will partition between the two phases to a different extent. 3) two phases can be separated by gravity or other mechanical means.

CHALLENGE FOR DISTILLATION COLUMN

Inaccurate liquid level indication 

- causes many expensive operating problems.

- high liquid levels damage equipment.

P&I DRAWING OF DISTILLATION COLUMN

SPECIFICATIONS OF TRANSDUCERS• Measuring principle of level transducers:

1. Radar

2. Guided Wave Radar

3. Ultrasonic

4. Capacitive

5. Hydrostatic

6. Radiation-based

7. Vibration

8. Conductive

LEVEL CONTROL

There will be two level loops on a distillation column as:

• the column base level must be maintained at an acceptable value.

• the reflux drum level must be maintained at an acceptable value.

• 1. Radar – Vegapuls 62

for level measurement of liquids under difficult conditions

Specs Details

Measuring Range up to 35 m

Process fitting thread from G1½, 1½ NPTflanges from DN 50, 2"

Process temperature -200 … +450 °C

Process pressure -1 … +160 bar (-100…+16000 kPa

Accuracy +/- 2 mm

SIL qualification Optionally up to SIL2

• 2. Guided Wave Radar – Vegaflex 86

for continuous level and interface measurement of liquids

Specs Details

Version exchangeable cable probe(ø 2 mm, ø 4 mm)exchangeable rod probe(ø 16 mm)coax probe(ø 42 mm)

Measuring Range cable probe up to 75 mrod probe up to 6 mcoax probe up to 6 m

Process fitting thread from G1½ , 1½ NPTflanges from DN 50, 2"

Process temperature -196 … +450 °C

Process pressure -1 … +400 bar(-100 … +40000 kPa)

Accuracy +/- 2 mm

• 3. Ultrasonic – Vegason 61

ultrasonic sensor for continuous level measurement

Specs Details

Measuring Range in liquids: 0.25 … 5 min bulk solids: 0.25 … 2 m

Process fitting thread G1½, 1½ NPT

Process temperature -40 … +80 °C

Process pressure -0,2 … +2 bar(-20 … +200 kPa

Accuracy +/- 10 mm

SIL qualification optionally up to SIL2

• 4. Capacitive – Vegacal 62

capacitive rod electrode for continuous level measurement

Specs Details

Version partly insulated rod

Measuring Range up to 6 m

Process fitting thread from G¾, ¾ NPTflanges from DN 25, 1"

Materials steel, 316L, PTFE

Process temperature -50 … +200 °C

Process pressure -1 … +64 bar(-100 … +6400 kPa)

SIL qualification optionally up to SIL2

• 5. Hydrostatic – Vegawell 52

suspension pressure transmitter for continuous level measurement of

liquids

Specs Details

Measuring cell CERTEC

Sensor diameter rom 22 mm

Measuring range 0 … +60 bar (0 … +6000 kPa

Process temperature -20 … +80 °C

Deviation in characteristics 0.2 %; 0.1 %

• 6. Radiation-based – Fibertrac 31

for continuous measurement of liquids and bulk solids

Specs Details

Version partly insulated rod

Measuring Range up to 6 m

Process fitting thread from G¾, ¾ NPTflanges from DN 25, 1"

Materials steel, 316L, PTFE

SIL qualification optionally up to SIL2

• 7. Vibration – Vegaswing 61

vibrating level switch for liquids

Specs Details

Materials 316L, Hastelloy, ECTFE,PFA, enamel

Process fitting thread from G¾, ¾ NPTflanges from DN 25, 1"hygienic fitting

Process temperature -50 … +250 °C

Process pressure -1 … +64 bar (-100 … +6400 kPa)

SIL qualification optionally up to SIL2

• 8. Conductive – Vegakon 66

conductive multiple rod level switch

Specs Details

Version compact level switch

Probe length up to 4 m

Process fitting thread G1½

Materials PPN

Process temperature -40 … +100 °C

Process pressure -1 … +6 bar(-100 … +600 kPa)

COMPARISON BETWEEN EACH TYPES OF TRANSDUCERSType of transducers Comparison

Vegapuls 62 (Radar) Both radar signals and microwaves travel at the speed of light but for radar, frequency is from 88 to 108 MHz,

Vegaflex 86 (Guided Wave Radar) microwaves range from 1-300 GHz

Vegason 61 (Ultrasonic) have limited of range with low temperature limitation

Vegacal 62 (Capacitive) have problem with electrode rod where gas produce from distillation might affect measurement

Vegawell 52 (Hydrostatic) have problem with temperature limitation

Fibertrac 31 (Radiation-based) they require a gamma radiation source and are relatively expensive

Vegaswing 61 (Vibration) hard to measure due to measure target is gas

Vegakon 66 (Conductive) has limitation in temperature

REASONS OF CHOOSING GUIDED WAVE RADAR FOR OUR PROCESS PLANT

• The VEGAFLEX 86 level sensor measures maintenance-free all liquids under extreme pressure and temperature conditions.

• Even in applications with build-up, foam generation and condensation, the sensor delivers precise and reliable measured values.

• In saturated steam applications, a special reference probe ensures a density-independent measurement.

• offers an economical level and interface measurement for your application.

• The guided microwave enables a simple, time-saving and reliable setup

REASONS OF CHOOSING COLUMN PRESSURE WITH VEGABAR 51

• The VEGABAR 51 pressure transmitter with its wide temperature range is particularly suited for this application – even extreme temperature fluctuations during the start-up phase in the column do not affect the transmitter.

• The sensor version with isolator can even be implemented in temperatures up to 752°F (400°C).

• Reliable measurement independent of foam generation and tank installations

REASONS OF CHOOSING ORIFICE METER TECHNOLOGY FOR FLOW CONTROL

• Measures a wide range of flow rates

• Inexpensive when compared to many other flow meters

• Accurate

REASONS OF CHOOSING RESISTANCE TEMPERATURE DETECTOR (RTD) SENSOR FOR TEMPERATURE MEASUREMENT

• high accuracy is required in the range of 400K.  Since accuracy is required, a thermocouple is not recommended. 

• Since the temperature range is outside the region for a thermistor, an RTD sensor is recommended.

• Since there are a number of temperature measurements to be made, like in a distillation column, having a temperature instrument for every point can be cost prohibitive. Thus, high density temperature transmitters such as RTD must be used.

MANIPULATED VARIABLES AND CONTROLLED VARIABLES OF A DISTILLATION COLUMN

No Controlled Variables Manipulated Variables

Control Valve

1 Column pressure Condenser duty Coolant flow V1

2 Concentration (temperature) of distillate

Reflux flow rate Reflux flow V2

3 Liquid level in the reflux drum Distillate flow rate Distillate flow V3

4 Concentration (temperature) of bottoms

Re-boiler duty Heat flow V4

5 Liquid level in the column base Bottoms flow rate Bottom flow V5

Q & A SESSION

THE END

THANK YOU