Envent 131S User manual

Gas Chromatograph
Models: 131S & 132S
User’s Manual
Revision 7.1
05 October 2021

Table of Contents
1.0 Introduction.............................................................................................................................. 1
1.1 About This Manual.................................................................................................................... 1
1.2 Warranty and Liability Statements .......................................................................................... 1
1.2.1 Limitation of Warranty ................................................................................................ 1
1.2.2 Disclaimer .................................................................................................................... 2
1.3 Safety Information.................................................................................................................... 2
1.3.1 Key Symbols................................................................................................................. 2
2.0 Equipment Overview ................................................................................................................ 3
2.1 Theory of Operation ................................................................................................................. 3
2.1.1 Important Definitions .................................................................................................. 3
2.1.2 Gas Chromatography .................................................................................................. 4
2.1.3 Thermal Conductivity Detector (TCD)......................................................................... 4
2.1.4 Chromatogram Output................................................................................................ 5
2.1.5 Computational Analysis .............................................................................................. 6
2.2 External Components & Dimensions/Clearances.................................................................... 8
2.3 Technical Specifications......................................................................................................... 10
3.0 Installation.............................................................................................................................. 11
3.1 Unpacking............................................................................................................................... 11
3.2 Mounting Requirements......................................................................................................... 11
3.3 Electrical Connections............................................................................................................ 13
4.0 Operation................................................................................................................................ 16
4.1 Start-Up Procedure................................................................................................................. 16
4.2 Calibration Procedure ............................................................................................................ 20
5.0 Maintenance ........................................................................................................................... 23
5.1 Monthly Check-Up .................................................................................................................. 25
5.2 Spare Parts and Consumables ............................................................................................... 26
5.3 Filter Replacement Procedure ............................................................................................... 26
5.4 Sample Conditioning System Cleaning Procedure ............................................................... 28
6.0 Troubleshooting ..................................................................................................................... 30
Appendix A – Risk Assessment................................................................................................................... 32
Appendix B – Certifications........................................................................................................................ 36
Appendix C – Sealing Compound Information.......................................................................................... 37
Contact Us.. ................................................................................................................................................ 41

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 1
1.0 Introduction
1.1 About This Manual
This manual provides all information necessary for the installation, operation, maintenance, and
basic troubleshooting of the Envent Engineering 131S and 132S Gas Chromatograph analyzer.
This manual contains information essential to the safe and efficient operation of the 131S & 132S. This
manual should be read by all personnel who will be installing, operating, or otherwise interacting with
these models.
This manual focuses on the analyzer as a stand-alone unit. However, the sample gas must be
conditioned before entering the analyzer to prevent erroneous readings and/or damage to the
analyzer. This manual includes a recommended standard sample conditioning system configuration
that would ensure proper operation of the analyzer. The exact sample conditioning system used will
depend on the customer's requests at time of purchase. Refer to the analyzer’s documentation for
more information.
1.2 Warranty and Liability Statements
Products produced and supplied by the manufacturer (Envent Engineering Ltd), unless otherwise
stated, are warranted against defects in materials and workmanship for up to 18 months from the
shipping date or up to 12 months from the start-up date (whichever comes first). During the warranty
period the manufacturer can choose to either repair or replace products which prove to be defective.
The manufacturer or its representative can provide warranty service at the buyer's facility only upon
prior agreement. In all cases, the buyer has the option of returning the product for warranty service to
a service facility designated by the manufacturer or its representative. The buyer shall prepay all
shipping charges for products returned to a service facility. The manufacturer or its representative
shall pay all shipping charges for the return of products to the buyer. The buyer may also be required
to pay round-trip travel expenses and labour charges (at prevailing labour rates) if the warranty has
been violated. The warranty may be considered violated for any of the reasons listed below.
1.2.1 Limitation of Warranty
The foregoing warranty shall not apply to defects arising from:
•Improper or inadequate maintenance of the product by the user
•Improper unpacking or installation procedures
•Inadequate site preparation

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 2
•Unauthorized modification or misuse of the product
•Operation of the product in unfavorable environments such as at high temperatures, high
humidity, or in corrosive atmospheres
•Operation of the product outside of the published specifications
Envent Engineering Ltd carries no responsibility for damage caused during transportation or
unpacking, unless otherwise specified in the incoterms.
An extended warranty may be available with certified start-up. Contact Envent Engineering Ltd for
details.
Envent Engineering Ltd reserves the right to change the product design and specifications at any time
without prior notice.
1.2.2 Disclaimer
No other warranty is expressed or implied. The manufacturer specially disclaims the implied
warranties of merchantability and fitness for a particular purpose. The sole remedy of the buyer shall
in no case exceed the purchase price of the analyzer. The manufacturer shall not be liable for personal
injury or property damage suffered in servicing the product. The product should not be modified or
repaired in any manner differing from procedures established by the manufacturer.
1.3 Safety Information
The procedures and settings outlined in this manual constitute what is considered proper use of the
equipment in question. The equipment was designed and tested under the assumption that these
procedures and settings will be adhered to. Applying values outside of the provided ranges (such as
permitting excessive pressures) or modifying provided procedures is considered improper use of the
equipment. Envent Engineering Ltd is not responsible for any injury or property damage caused by
improper use of the equipment. Once in the field, the user is solely responsible for the safe operation
of the equipment.
1.3.1 Key Symbols
The following symbols are used throughout the manual to call attention to important information. We
recommend familiarizing yourself with them before reading further.
•Indicates a potential hazard that, if not properly addressed, could result in damage
to the equipment or injury to the operator.
•Indicates additional information intended to help clarify an earlier statement or to
aid in the reader’s understanding of a given topic

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2.0 Equipment Overview
2.1 Theory of Operation
2.1.1 Important Definitions
Carrier
A gas which pushes the sample through the columns for analytical
separation (also known as the "mobile phase")
Chromatogram
The output of a Chromatograph; a record of the output from the GC
Detector and crucial to determining mole percent concentration;
typically represented as a graph or chart
Chromatograph
A device designed to separate a mixture into individual components
Column
An analytical device which causes components, in a sample, to separate
from one another through physical interaction (also known as the
"stationary phase")
Component
Any one of the multiple chemicals which make up the sample, whether
of interest to analyze or as a contaminant
Contaminant
A component which is not desired to be analyzed; may or may not cause
interference
Elute
The action of a component exiting a column
Integrator
Hardware/Software responsible for computing the output of the
detector into a chromatogram
Response Factor
A factor important to determining an analyte's concentration - created
during calibration
Retention Time
The time at which the most concentrated part of a component elutes
from the column and is detected, usually referenced from the start of
analysis or the start of sample injection
Sample
A mixture containing one or more components which the analyzer will
measure
TCD
Thermal Conductivity Detector
Thermal Conductivity
A measurement of a material's ability to conduct heat

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 4
Thermistor
A device which reacts to temperature changes with a change in
resistance
Wheatstone Bridge
An electrical circuit designed to measure an unknown electrical
resistance by balancing two legs of a bridge circuit
2.1.2 Gas Chromatography
Gas Chromatography is achieved by separation of a mixture (a sample) into its individual components
so that the concentration of each component can be measured. There are three basic parts to
chromatography: (1) The sample; (2) the mobile phase (also known as the “carrier” (typically Helium
or Hydrogen)); and (3) the stationary phase (the analytical columns). Separation occurs when the
carrier pushes the sample through the columns; the analytical columns are designed such that the
components of the mixture move at different rates. In this theory, the components are separated and
elute from the column at different times. Detection of the separated components is done using a
Thermal Conductivity Detector (TCD). The integrator (electronics) takes the output from the TCD and
turns it into a graph (millivolts over time) which has peaks representing the time, and intensity, of
each component eluting from the column. This output is called a chromatogram and is the basis of
concentration readings and subsequent calculations that need to be performed.
2.1.3 Thermal Conductivity Detector (TCD)
The TCD block consists of two heat-sensitive thermistor beads mounted to individual chambers.
Thermistors respond to a change in temperature with a change in resistance. These beads are wired
together as part of a balanced wheatstone bridge (see Figure 1), one bead is designated as the
“reference” and the other as the “measurement”. As seen in Figure 1, the reference thermistor
receives carrier only, while the measurement thermistor receives the carrier as well as the eluted
components from the sample.
When both the thermistor beads are receiving carrier gas only, the resistance of the wheatstone
bridge system remains unchanged and so the voltage measured by the integrator does not change;
this state provides the GC with the baseline measurement. Alternatively, when a component elutes
from the analytical column, its individual thermal conductivity will slightly change the temperature in
the measurement cell which changes the resistance balance of the bridge – this change causes the
integrator to detect a millivolt difference and a peak is generated on the chromatogram.

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Figure 1. Diagram of the Wheatstone Bridge and TCD
2.1.4 Chromatogram Output
When a resistance change occurs between the two thermistors, and the bridge becomes unbalanced,
the millivolt signal is detected, and the integrator interprets this as a peak. The peak is displayed on a
chromatogram (see Figure 2), where the peak’s relative size (height and width) is correlated to the
concentration of the component in the sample.
Figure 2. Labeled Diagram Depicting a Chromatogram Peak

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2.1.5 Computational Analysis
Integration is performed on the peaks of the chromatogram to determine the area of each peak. The
area of a peak is directly correlated to the concentration of the component in the sample, by mole
percent. For the integrator to compute the mole percent concentration of a component, two factors
are required: the response factor (RF) and the retention time (RT). The retention time is the time at
which the peak’s apex occurs (usually in seconds), in relation to the start of the chromatogram – this
factor is important to identify which component belongs to which peak.
Calibration, of the analyzer, is required to determine the response factor for each component in the
sample. The response factor of a component is equal to its peak area divided by the mole percent
concentration of the calibration standard.
The response factor is calculated as such:
=
 %
Where,
RFn
Response Factor of component “n”
An Area of component “n”
Cal %n The calibration standard’s listed mole % of component “n”
During analysis, component concentrations are determined by the following calculation:
 %=

Where,
Mole %n Concentration of component “n” by mole percent
An Area of component “n”
RFn Response factor of component “n” determined during calibration
After the concentration of each component is determined (by mole percent), the total un-normalized
mole percent is calculated with the following calculation, which sums the mole percent
concentrations of all the analyzed components:
 %=� %

=1
Where,
Mole %T Total un-normalized mole percent
K Number of components included in the total
Mole %n Individual mole percent concentration of component “n”

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 7
Normalization is the process by which the results of the chromatogram are adjusted such that the
mole percent total equals one hundred percent. This computation is useful when the un-normalized
concentration total does not equal one hundred percent – this will almost always be the case as there
are always variances which affect the summed total. These variances typically stem from minor
changes due to environmental effects (temperature, humidity, pressure), electrical noise differences,
and/or minor contaminants or impurities in the sample or carrier. Normalization should not be used
as a tool to combat inherently poor chromatography (some examples include inefficient sample
conditioning, major contaminants or interference in the readings, and changes in pressure or flow of
the sample or carrier). Each component’s concentration is normalized using the following calculation:
 %= %
 %×100%
Where,
NMole %n Normalized concentration (by mole percent) of component “n”
Mole %n Un-normalized concentration (by mole percent) of component “n”
Mole %T Total un-normalized mole percent

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2.2 External Components & Dimensions/Clearances
1. ETL cETLus nameplate
2. Upper XP enclosure for electronics
3. Lower Stainless-Steel enclosure for GC Oven
4. Male to Female Aluminum Union
5. Solenoid Valves
6. Vertical mounted seals
7. 1/2'' Myer hubs
8. 3/4'' NPT entries
9. External Ground Connection
10. Cable Gland
11. 1/2'' NPT entries
Figure 3. Model 131S External Components & Dimensions/Clearances Inches [cm]

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 9
1. ETL cETLus nameplate
2. Upper enclosure for electronics
3. Lower Stainless-Steel enclosure for GC Oven
4. 1/2'' Myer hubs
5. Rigid Conduit Nipples
6. Solenoid Valves
7. External Ground Connection
8. Cable Gland
Figure 4. Model 132S External Components & Dimensions/Clearances Inches [cm]

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 10
2.3 Technical Specifications
Analyzer Specification
Mounting
Wall-mount (Standard), Free-standing (Optional)
Supply Voltages
100-240 VAC 50/60 Hz (40 Watts running, 50 Watts Start-up)
Fuse Rating: 5 Amps, 250V, Slow blow, Size: 0.201'' Dia x
0.787'', Package/Case: 5 mm x 20 mm
Certification
Model 131S: cETLus Class I, Division 1, Groups BCD Temp
Code T3. Ambient temperature -20 to +55 °C (-4 to +122 °F) –
For indoor use only.
Model 132S: cETLus Class I, Division 2, Groups BCD Temp
Code T3. Ambient temperature -20 to +55 °C (-4 to +122 °F) –
For indoor use only.
Oven
Airless heat sink, maximum 84 °C (183.2 °F)
Display
Graphic Liquid Crystal Display; menu is scrolled by internal
button or magnetic wand (131 Model)
Valves
6-port and 10-port diaphragm valves
Carrier Gas
Typically UHP helium 7 to 20 cc/min (typical flow rates).
Offering 12-14 Months operation in C6+ BTU applications (2
Column App). 6-8 Months operation in C6+ BTU applications
(3 Column App).
Detector
Thermal Conductivity Detector (TCD)
Gating Options
Fixed-time, auto-slope detection with automatic gating of
peaks on calibration or analysis
Streams
Up to 8 streams (including calibration stream)
Electronics
Envent designed ARM7 CPU based analyzer platform
Analog Inputs
Three sensor inputs filtered with transient protection
Analog Outputs
Dual isolated 4-20 mA (2 wire standard, loop powered)
Communications
RS-232, RS- 485, TCP/IP
Modbus
Enron, Modicon 16, Modicon 32

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 11
3.0 Installation
3.1 Unpacking
The 131S Model GC analyzer weighs approximately 68 kg (150 lb) and the 132S Model GC analyzer
weighs approximately 36 kg (80 lb) (13.6 kg (30 lb) added with sample conditioning system).
Unpacking and transporting requires a minimum of two persons.
Upon arrival, the packaging should be immediately inspected for any external damage that may have
occurred during shipping. If any damage is present, please contact Envent Engineering Ltd and
request that the carrier's agent be present when the analyzer is unpacked. If a disagreement arises,
the incoterms agreed to by the seller and the customer will overrule any dispute.
Once the integrity of the packaging has been confirmed open the shipping container and remove the
packing materials from the shipping box. Remove all provided components from the shipping
container and inspect them for any damage that may have been sustained during shipping. Compare
the provided components to the shipping manifest to ensure that all parts are present.
3.2 Mounting Requirements
The 131S is designed for cETLus Class 1, Division 1 (132S for Division 2), Groups BCD, Temp Code T3
(Tamb -20°C to +55°C). These models are designed for indoor use only. Ensure that the analyzer
received is suitable for the electrical classification of the installation site.
The analyzer should be mounted in an enclosed area in which it is not exposed to vibrations,
excessive pressures, temperatures, or environmental variations.
The selected installation site should provide adequate room for maintenance and repair procedures.

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The installation site should be as close as possible to the process stream being measured. The sample
delivered to the analyzer must be representative of the stream and as such, should be taken from a
point as close as possible to the analyzer. This proximity will prevent lag times and sample
degradation in the lines.
A bypass sweep is recommended to reduce sample lag time if the sample lines are longer than 4.6 m
(15 ft) or if they are being kept at high pressure (2758 kPag (400 psig) and above). If the line pressure is
over 2758 kPag (400 psig), a heated regulator is recommended.
All connections must be leak tight to ensure the safety of the user and the operation of the analyzer.
Sample should not exceed 172 kPag (25 psig) in sample system. Damage to sample system may result.
Model 131S only:
•No modifications or repairs to the flame paths are permitted.
•Substitution of components may impair flameproof safety and suitability for Class I, Division
1.
•All NPT thread entries must meet the minimum engagement of 5 threads.
•XP enclosures must have conduit plugs installed for unused conduit entries.
•Conduit seal(s) must be installed at a minimum distance of 18'' from any XP enclosure's
conduit entries.
•Conduit seals must be poured after wiring is completed and before powering up the unit.
Refer to Appendix D for more information on the conduit sealing compound.

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 13
3.3 Electrical Connections
For 120 – 240 VAC powered analyzer: A disconnect device rated 240 VAC and 5A max is required and is
to be installed in accordance with local electrical codes.
Do not disconnect equipment unless the power has been switched off or the area is known to be non-
hazardous.
External ground wiring must be 12-10 AWG (3.31 – 5.26 mm2).
External IS Ground wiring must be 22 AWG (0.33 mm2) green insulated conductor.
Power supply wiring must be rated for a minimum of 90 °C (194 °F) above surrounding ambient
temperature.
Relay Outputs on Mainboard (Relay 1 to 4) P7, are limited to 120VAC max, or used as dry contacts.
The 4-20 mA output requires a 24 VDC power loop which can be supplied by the analyzer.

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Figure 5. Electrical Customer Connections

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Figure 6. IS Ground Customer Connections

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4.0 Operation
4.1 Start-Up Procedure
Oven temperature can exceed 84 °C (183 °F). Caution should be taken when touching the inside
surfaces of the GC Oven.
Before commencing the start-up procedure for the analyzer, please ensure that all sections within
“Installation” (Section 3.0) have been understood and addressed. Do not proceed until this is done as
significant safety hazards can arise if the analyzer is not properly set-up prior to start-up.
During start-up, it is possible that the analyzer and/or the SCS will be contaminated with undesired
liquids/solids (such as a scavenger solution). The flow meter should be inspected for liquids to ensure
that the ball moves freely. Check all filters to ensure no contaminants will be forced into the analyzer
after introduction of pressurized product.
Excessive temperature and environmental variations may affect the integrity of the calibration gas.
Should heavier components condense into the liquid phase, the composition of the bottles could
change. Calibration cylinders should be installed with a cylinder riser to keep the bottle off the floor.
For high heating value cylinders, a heated bottle blanket may be required to ensure the contents do
not condense.
Step 1. Ensure that the analyzer power supply and range are suitable for the application.
Step 2. Check that the hazardous location rating is suitable for the installation location.
Step 3. Select an installation location that is close to the sample point.
·Ensure that the selected installation site provides adequate room for maintenance
and repair.
Step 4. Bolt the analyzer to the wall or secure Unistrut to a solid surface. 3/8” x 1” bolts are
recommended for installation.
Step 5. Wire power, analog outputs, discrete inputs & outputs, and communications to the GC
Step 6. Check to ensure all bottles are securely fastened to wall mount brackets and

Envent Engineering Ltd – 131S & 132S User’s Manual – Revision 7.1 Page 17
regulators are installed on each bottle, and leak tested.
Dual stage regulators must be installed on the carrier gas, usually Helium.
Single stage regulators can be installed on the calibration gas and process gas
streams.
Step 7. Tube the sample inlet(s), calibration inlet(s), sample sweep(s), sample vent and carrier
vent lines to the GC.
1/4” 316 stainless steel tubing is recommended for the sample tubing.
1/8” 316 stainless steel tubing can also be used if the response time of the
analyzer is of particular concern.
All fittings in the sample and vent lines must be 316 stainless steel.
The sample vent line should be tubed in 3/8” stainless steel tubing to a
maximum of 6’
1/2” 316 stainless steel tubing should be used for vent lines exceeding 6’
The tubing should be installed with a slight downward slope and should be as
short as possible.
The sample vent line can be tubed to atmosphere, low pressure flare or
returned to process. If returning to process or low pressure flare a 1/3 psi
check valve should be used.
The carrier vent line must be tubed to atmospheric pressure only.
The ARV (Atmospheric Reference Valve) vent line must be tubed to
atmospheric pressure only.
For systems with stream selectors installed, double-block-and-bleed vent
must be tubed to atmospheric pressure only.
Step 8. With the sample pressure turned off (sample inlet valve closed). Apply power to the
GC. The display will illuminate.
Step 9. Turn on carrier pressure from bottle. Perform a Helium Leak Test. Factory plugs are
installed on the carrier inlet/outlet lines to protect the columns from contaminants
during shipping – remove these plugs when carrier gas is ready for the analyzer.
Step 10. Turn on carrier pressure from bottle and verify GC carrier pressure regulator is set to
the desired pressure as outlined in the Factory Calibration Certificate provided with
the GC.
Step 11. Once the GC oven is at the set point (approximately 1-2 hours), turn on calibration gas
and sample gas to all stream inlets. Set flows and pressures according to the
requirements of the system (typically a label on the back-pan or refer to drawings).
Step 12. Connect serial cable to the GC from Laptop or a PC.
Step 13. Load Envent ICE onto a laptop or PC.
Step 14. Log onto the GC and validate communications.