Gas and Liquid Sampling Device

AC Liquefied Gas & Gas Sampling Device

AC Liquefied Gas & Gas Sampling Device Hardware section

Introduction The AC Liquefied and Gas Sampling Device is a sampling module that allows the user to reproducibly introduce gaseous and liquefied (LPG) samples into a gas analyzer. A builtin heated vaporizer vaporizes the liquefied samples, so they are introduced into the gas chromatograph in the gaseous state. The unit is placed adjacent to the gas chromatograph and connected to the gas sample loop(s) of the gas analyzer. It is configured with a heated vaporizer, two rotameters, a selection valve and a clamp to hold the sample bombs.

Partnumber Description 68100.000

Gas and Liquid Sampling Device excluding vaporizer 

68100.001

Gas and Liquid Sampling Device including 110 V vaporizer 

Options : - low temperature (24-104°C) * - high temperature (104-194°C) * 68100.002

Gas and Liquid Sampling Device including 220 V vaporizer 

Options : - low temperature (24-104°C) * - high temperature (104-194°C) * * NOTE : Temperature adjustable inside the vaporizer, depending on the desired temperature.

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AC Liquefied Gas & Gas Sampling Device Hardware section

Configuration The sampling device is a separate unit configured with a heated vaporizer, a rotameter, a clamp to hold the sample bombs, two selection valves and the necessary plumbing material. The schematic overview can be found in figure 1.

Gaseous Sample in

1

to Gas Sampling Valve GC

from Gas Sampling Valve GC

5

6

3

G Selection Valve A L

Needle valve

Vent 13

8

4 12

Selection Valve B

Outlet pressure adjustment

Liquefied Sample in

7

9

rotameter 2 13

10

out

in

Heated Vaporizer

Figure 1 – Schematics

Principle Both Liquefied and gaseous samples can be mounted on the device. With the Selection Valve A, the proper position is chosen. So for gaseous samples, position 3 (of selection valve A) is selected. The sample from the sample bomb directly flows via Selection Valve A through the gas sample valve of  the gas chromatograph. It then goes through the rotameter to Vent. The effluent flow can be adjusted with the needle valve (8) underneath the rotameter. For Liquefied samples the Selection Valve A must be put in the Liquid position (4) and selection valve B in position (12). So the liquefied sample is introduced in the Heated Vaporizer. Here it is vaporized. The effluent gas goes to the gas sampling valve of the gas chromatograph and finally again through the needle valve to vent. The effluent flow should be adjusted with the outlet pressure adjustment (10), a special tool to adjust the outlet pressure is delivered with the system.

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AC Liquefied Gas & Gas Sampling Device Hardware section

Configuration

Figure 2 – Over view 1. Gas Sample In (male Swagelok 1/8”) 2. Rotameter  3. Selection Valve A

Position: ‘Gas’ (3)

4. Selection Valve A

Position: ‘Liquid’ (4)

5. To Gas Sampling Valve Gas Chromatograph (male Swagelok 1/8”) 6. From Gas Sampling Valve Gas Chromatograph (male Swagelok 1/8”) 7. Liquefied Sample in (male Swagelok 1/8”) 8. Needle Valve Rotameter  9. Vent (male Swagelok 1/8”) 10. Outlet pressure adjustment Heated vaporizer (5/32” Allen wrench) 11. Power supply 12. Selection Valve B

Position: ‘to GC’ (12)

13. Selection Valve B

Position: ‘to vent’ (13)

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AC Liquefied Gas & Gas Sampling Device Hardware section

Power supply Configuration

Figure 3 – Front and Rear view

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AC Liquefied Gas & Gas Sampling Device Hardware section

Installation The Sampling device must be placed adjacent to the gas chromatograph on the lefthandside. The Gas sampling valve of the chromatograph must then be connected to the Sampling device. Using 1/16” Stainless steel capillary tubing, position 5 is connected to the ‘Gas Sample in’ from the gas chromatograph. Position 6 is connected to the ‘Gas sample out’ from the gas chromatograph. It is recommended to connect a length of 1/8” t ubing from the Vent position (9) on the rear side of the device to a fume hood. The power plug can be plugged in, this is the power supply of the heated vaporizer. Please refer to figure 4 for the location of the temperature adjusting screw. This screw is used to set the temperature of the heated vaporizer depending on the boiling point range of the sample.

Figure 4 – Wiring diagram

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AC Liquefied Gas & Gas Sampling Device Hardware section

Gaseous Samples To inject gaseous samples, the gas sample bomb must be vertically mounted in the clamp. The top outlet valve must be connected to the ‘gas sample in’ (1) position on the device and the selection valve A must be switched to the ‘Gas’ position. (3) Now with the needle valve of the rotameter (8) in the closed position (turned entirely clockwise) the outlet valve of the sample bomb is opened. Then slowly the rotameter  needle valve is opened until a constant flow is obtained. (2 on scale corresponds with about 30 mLs/minute) The sample loop in the gas chromatograph is now being flushed. After one minute the analysis can be started. To obtain proper results, it is important to introduce and analyse samples and calibration blends in the same way. Therefore if analysis is done whilst the sample loop is being flushed, the flow through the gas sample loop must always be identical for sample and calibration analyses. If atmospheric injection is preferred, care must be taken to allow the same wait time after  the flow through the sample has been stopped for both sample and calibration runs. (The stopwatch function of the GC display can be helpful in this)

Gaseous Sample in

1

from Gas Sampling Valve GC

to Gas Sampling Valve GC 5

6

3

G Selection Valve A L

Needle valve

Vent 13

8

4 12

Selection Valve B

Outlet pressure adjustment

Liquefied Sample in

7

9

rotameter 2 13

10

out

in

Heated Vaporizer

Figure 5 – Flow path gaseous samples

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AC Liquefied Gas & Gas Sampling Device Hardware section

Liquefied Samples To inject liquefied samples, the sample bomb must be mounted in the clamp, and the bottom valve must be connected to the ‘Liquefied Sample in’ position of the device*. The selection valve A must be switched to the ‘Liquid position’. (4), selection valve B must be in position (12). The outlet pressure adjustment (10) can be adjusted with the special tool supplied with the system. Now with the outlet pressure adjustment (10) in the closed position and the needle valve of the rotameter (8) opened, the outlet valve of the sample bomb is opened. Then slowly the outlet pressure adjustment (10) is opened until a steady flow (about 30 ml/minute) is obtained. (2 on scale corresponds with about 30 ml /minute). The sample loop in the gas chromatograph is now being flushed. Several minutes of time must be allowed to pass in order to properly flush the vaporizer and to obtain a homogeneous sample. Prior to analysis, selction valve B must be switched to position (13) in order to vent excess sample. The pressure in the sample loop now becomes atmospheric. To obtain proper results, it is important to introduce and analyse samples and calibration blends in the same way. Therefore if analysis is done whilst the sample loop is being flushed, the flow through the gas sample loop must always be identical for sample and calibration analyses. Please refer to figure 6.

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AC Liquefied Gas & Gas Sampling Device Hardware section

Gaseous Sample in

1

to Gas Sampling Valve GC

from Gas Sampling Valve GC

5

6

3

G

Needle valve

Vent

Selection Valve A L

8

4 12

Selection Valve B

Outlet pressure adjustment

Liquefied Sample in

7

9

rotameter 2 13

10

out

in

Heated Vaporizer

Figure 6 – Flow path liquefied samples

NOTE :

A too high sample flow can be the cause of a not totally evaporated sample in

the sample loop. NOTE :

If the sample bomb is equipped with a diptube then the ‘liquid out’ of the diptube

must be connected to the ‘Liquefied Sample in’ position of the device! NOTE :

To vent excess sample, selection valve B must be switched to position (13).

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AC Liquefied Gas & Gas Sampling Device Hardware section

Heated Vaporizer  The heated vaporizer is built in to vaporize the liquefied samples. It consists of a heat exchanger and a pressure control section. The liquefied sample enters the heated body, where it is vaporized. The outlet pressure is controlled by a regulator (10) which can be accessed at the back of the sampling device.

Figure 7 – Heated vaporizer 

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Part numbers: 28024.210 Heated Vaporizer (220V) 24 – 104 °C

■

28024.220 Heated Vaporizer (220V) 104 – 194 °C

■

28024.211 Heated Vaporizer (110V) 24 – 104 °C

■

28124.221 Heated Vaporizer (110V) 104 – 194°C

■

Standard Specifications Body:

Stainless steel

Model:/Port configuration: Side entry Seat:

Peek

Temp range:

75 °F to 220 °F (24 °C to 104 ° C) 215 °F to 380 °F (104 °C to 194 °C)

Outlet range:

0-10 Psi

Power:

100 watt

Max pressure inlet:

2000 Psi

Typical applications are •

Vaporize liquid hydrocarbons Ethylene, LPG, Butane. Natural gas sampling

•

Heated gas samples to prevent condensable drop out

Installation and Usage •

Installation Vaporizer involves plumbing lines and electrical connection, use only with AC applications.

•

Use instructions regarding connections as described below:

•

Allways check the connection for leaks.

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AC Liquefied Gas & Gas Sampling Device Hardware section

General mounting instructions •

Disconnect power before servicing or replacement.

•

Plug in the power cord to the specified voltage.

Adjusting the proper temperature •

Disconnect power.

•

Remove left cover from unit.

•

Open the vaporizer cylindrical cover plate to get access to the power cable.

•

Adjust the proper temperature setting. (position 1-6)

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