Foundation Support

• Large Instrument analysers when mounted on the ground are bolted to a concrete block. The concrete block is usually casted outside the plant. The earth is then excavated and the concrete block is inserted into the excavated hole. Analyzer is then bolted on to this concrete The concrete block is usually designed by a civil engineer

Analyzer Sampling Systems

• Purpose of analyser sampling system is
• To obtain representative sample
• To condition the sample
• To accomplish stream switching
• To ensure safety
• To allow adequate sample time
• The 5 main elements of sampling system
• Sample take off
• Sample pre conditioning system
• Sample transport line
• Sample conditioning system
• Sample return/dispose
• Sample Take off
• Sample take off probe is usually angle cut to avoid solid particles from entering the sampling system.
• 
• Very thick schedule (80 and above) to avoid it from getting corrode
• Is usually flanged type
• Rules for using sample take-off probe or sample tap
• For relatively clean process streams of 2" and below pipe, a simple sample tap may be adequate, however sample take-of probe is preferred.
• A sample probe is preferred because solid particles tend to move at the rear of the pipe
• For both types, take sample from the TOP of the process line for Vapours
• For both types, take sample at the side of the process line for liquids.
• Never take sample from the bottom of the process line since there may be sediments (such as piping sediments)
• General guideline is to use sample take-off probe to ensure representative sample
• Sample preconditioning
• Purpose is to for the process sample to suit the analyser requirements (such as pressure, temperature and flow rate)
• Main components are pressure regulator, pressure gauge, cooler, sample vaporizer
• Sample vaporizer is to provide heat to maintain the gas sample at a gas phase after pressure is reduced
• Sample cooler is to provide cooling. Conventionally, we use a tube-in-tube method
• Sample Transport Line
• Type of transport line
• Single transport line
• For short transport line (<30m)
• Fast loop system
• Long transport time
• Lag time is undesirable
• Sample needs to be in single phase along the transport line
• Use electrical heater to ensure sample is heated
• Gas sample need to be maintained above it’s dew point
• Liquid sample needs to be maintained below it’s boiling point
• The sample is usually returned back to process. In case if pressure is inadequate, the sample may be returned back to the following:-
• For hydrocarbons, it can be returned either to:-
• DOC(Oil contaminated drain) or Oily water sewer . The sample will then flow to a waste water treatment plant. Some DOC design goes straight to slop tank this however will run a risk causing slop to be over contaminate
• SOP(Slope drain). The sample will flow straight to slop pit and pumped back to slop tank and the reprocessed back. This is different to DOC since it does not go through a waste water plant. Normally SOP’s are seen in tankage area where WWTP is too far away for the waste to be pumped.
• For clean water, it can be returned back to DAC(Accidentally oil contaminated drain) or oily water sewer. The sample will then go straight to final pond/bio pond

Gas Chromatograph Analysers

• GC is used to analyse product concentration. A constant volume sample is injected into the GC column. The injection is done by a sample injection valve
• GC must be temperature controlled. Temperature control is important for
• Column separation - A 1 degree C temperature change will have a 3% effect in retention time
• Gas sample injection – Temperature is inversely proportionate with volume injection
• GC’s can be used for both liquid and gas sample
• For liquid sample,
• The sample boiling point must be adequately low to ensure that the GC oven can vaporize the sample. If the sample boiling point is too high, a vaporizer may need to be use
• The sample pressure must also be adequately high (~>2kgcm2) to ensure. However, if the pressure is too high , a pressure reducer need to be installed
• For liquid, there are 2 types of sampling valves.. These valves range from 0.1 to 3ul injection
• Liquid sampling valve
• is used when the boiling point is high.
• The LSV incorporates a vaporizer to vaporize the sample
• Rotary sampling valve
• TCD reading – Small temperature deviations in TCD will cause significant zero/span shifts
• Having a lower temperature will prolong the lifetime of columns and valves
• Carrier Gas System
• The important purpose of carrier gas system is to provide a stable transport and detection medium for the components of the sample
• Nitrogen, Hydrogen, helium are used as carrier gas as they do not have interactions with the solutes. Carrier gas selection also depends on the type of detector used
• The carrier gas must fit the following criteria
• Water or oxygen in carrier gas will destroy most column materials (dewpoint must be less then -60 degC)
• 99.99% purity
• Organic components must be less than 5ppm
• Some GCs have a dehumidifier at their carrier gas system where a desiccant such as molecular sieves is use
• Carrier Gas Maintenance
• There should be 2 cylinder manifolds, one cylinder pressure set higher so that when the higher pressure cylinder finishes, the lower one will take over.
• There are 3 types of GC columns
• GC Ovens
• The most important function of the GC oven is to ensure constant temperature selectable between 5 degC up to 350 degC.
• Oven temperature is important as the higher the temperature, the faster components move in the GC oven. It is therefore practical to put it lower for better separation but slower cycle time. To high temperature in the other hand provides faster analysis but will reduce column life time due to column bleeding. It is best to put temperature as low as possible
• Aside from stability, temperature should also be evenly distributed. The unevenness of temperature distribution should not be more than 0.8 degC if a same performance with lab GC is expected
• Oven designs include
• Using a heater element.
• Heated-are blow-in method where air is heated and the blown in 4 sides pf the oven
• Air bath circulation method where air is heated also but is circulated with a fan. This method ensures good stability and evenness
• Gas Chromatograph Detectors
• The most common detectors are FPD and FID
• Slope Processing
• User will usually have to configure how the GC detects the slope. Slope detection is the prime method used for GC to recognize peaks. There are a few things that needs to be configured in slope detection which are
• The Gate time
• Gates are the point on which the GC will turn on a slope detection algorithm.
• There are 2 types of gates
• ON gate – This is the gate when the GC will start to detecting an increasing slope
• OFF Gate – This is the gate when the GC will start to detect when it should start find a decreasing slope
• User need to first configure the time when both Gates start
• Detection Slope
• Once a chromatograph signal have passed an ON gate time, the GC will start the slope detection algorithm.
• Before that, user will have to configure the ‘Detection Slope’ a parameter with a mV/s unit. Typically this value is set at 0.005mV/s. Increasing this value higher may cause the slope detection too late but decreasing the value may cause the slope to detect noises. The time when the slope is detected is called the Peak-ON time
• As the chromatograph further traverses, it will soon find the OFF Gate. This off gate will start another slope detection algorithm however, this time it will start to determine the PEAK-OFF time. Different GCs have different method of determining a gate off time. The usual method is to find a 0mV/s slope. Some GC
• The gate cutting method
• Gate cutting is to determine where to cut the baseline to determine the borders of integration
• There are 2 types of gate cutting methods:-
• Slope Gate – The GC will draw a straight line from the start gate and end gate
• Time Gate
• Detection slope
• Detection level
• The integration method
• The 2 most common gate methods are
• Time gat
• Slope gate
• The calibration of GC is done by using the following formula
• Concentration x Std Area = Measured Area x Reading Range x Calibration Factor
• Based on this formula, calibration is possible by altering 2 value namely “Std Area” or “Calibration factor”. However, in PPTSB/AMSB GC application, we only change “Std Area” as our standard practice.

Gas Chromatograph Columns

• When changing a GC column, one must allow 1 night of flushing. One must slightly increase the oven temperature
• Types of Column
• Packed
• Short length (1.5 to 10m)
• ID 2-4mm
• Have solid supports which is inert such as diatomaceous earth
• Diatamaceous earth is a naturlly found compound containing 86% silica, 5% sodium, 3% magnesium and 2% iron.
• This solid support is coated with a liquid or solid satationary phase
• The selection of this stationary phase coating depends on the type of analysis to be done
• Slow and inefficient
• Have higher capacity, though new technologies have allowed capillary column to have large capacity to
• Capillary Column
• Long length (25-60m)
• ID 0.25mm
• Mostly made of fused-silica with polyimide outer-coating
• Best for speed
• However only small samples
• Type of capillary column
• Wall coated open tubular (WCOT)
• Has tube walls coated with stationary phase
• Most commonly used
• Does not separate very light component well
• Some also call it FSOT (Fused silica open tubular)
• Support coated open tubular (SCOT),
• Has solid support on the tube walls which is coated with the stationary phase
• Solid support used is also normally diatomaceous earth
• Can handle larger samples than WCOT, so it is the best choice for very light components
• Also, for specific type of stationary, SCOT must be used.
• Most common stationary phase which must use SCOT is
• Molecular Sieve
• Divinylbenzene(DVB) - Used for C1 to C3 isomers analysis
• Alumina Al2O3 - Separation of isomers of C1 to C10
• PLOT (Porous Layer Open Tubular)
• Has porous layers on the walls of the tube which can be coated with stationary phase
• The pores itself can sometime be used as stationary phase
• Usually used for compounds that are gas at room temperature as it is able to create sharper peaks
• Common trade name for stationary phase columns. This table is taken from aegilent product brochur
• Most supports use diatomaceous earth. However, some advance supports have trade names such as
• Celite
• Chromosorb W, Chromosorb P, Chromosorb G, Chromosorb S
• Some chromosorbs have a AW notation, which means acid wash.

• Agilent Phase		Composition	Polarity	Approximate Temperature Range (�C)  (Isothermal/Programmed)*	Phases With Similar Selectivity
  General Applications
  HP-1ms, DB-1ms, HP-1, DB-1	Amines, hydrocarbons, pesticides, PCBs, phenols, sulfur compounds, flavors and fragrances	100% Dimethylpolysiloxane	Non-polar	From -60 to 325/350	BP-1, SPB-1, CP-Sil 5, Rtx-1, OV-1, SE-30, 007-1, ZB-1
  HP-5ms, DB-5, HP-5	Semivolatiles, alkaloids,drugs, FAMEs, halogenated compounds, pesticides, herbicides	5% Phenyl 95% dimethylpolysiloxane	Non-polar	From -60 to 325/350	SPB-5, XTI-5, Mtx-5, CP-Sil 8CB, SE-54, Rtx-5, BPX-5, MDN-5, Rtx-5ms, BP-5, ZB-5
  DB-5ms	Semivolatiles, alkaloids, drugs, FAMEs, halogenated compounds, pesticides, herbicides	5% Phenyl 95% dimethyl arylene siloxane		From -60 to 325/350	SPB-5, XTI-5, Mtx-5, CP-Sil 8CB, SE-54, Rtx-5, BPX-5, MDN-5, Rtx-5ms
  DB-1301	Aroclors, alcohols, pesticides, VOCs	6% Cyanopropyl-phenyl 94% dimethyl polysiloxane	Mid-polar	From -20 to 280/300	Rtx-1301, Mtx-1301, CP-1301
  DB-35, HP-35	CLP-pesticides, aroclors, pharmaceuticals, drugs of abuse	35% Phenyl 65% dimethyl polysiloxane	Mid-polar	From 40 to 300/320	Rtx-35, SPB-35, AT-35, Sup-Herb, MDN-35, BPX-35
  DB-35ms	CLP-pesticides, aroclors, pharmaceuticals, drugs of abuse	35% Phenyl 65% dimethyl arylene siloxane		From 50 to 340/360	Rtx-35, SPB-35, AT-35, Sup-Herb, MDN-35, BPX-35
  DB-1701, DB-1701P	Pesticides, herbicides, TMS sugars, aroclors	14% Cyanopropyl-phenyl 86% dimethyl polysiloxane	Mid-polar	From -20 to 280/300	SPB-1701, CP-Sil 19 CB, Rtx-1701, CB-1701, OV-1701, 007-1701, BPX-10
  HP-50+, DB-17	Drugs, glycols, pesticides, steroids	50% Phenyl 50% dimethylpolysiloxane	Mid-polar	From 40 to 280/300	Rtx-50, CP-Sil 19 CB, BPX-50, SP-2250
  DB-17ms	Drugs, glycols, pesticides, steroids	50% Phenyl 50% dimethyl arylene siloxane		From 40 to 320/340
  HP-88	FAMES	Approximately 88% Cyanopropyl arylene siloxane	High	From 0 to 260
  DB-200	Residual solvents, pesticides, herbicides	35% Trifluoropropyl 65% dimethyl polysiloxane	Polar	From 30 to 300/320	Rtx-200
  DB-210		50% Trifluoropropyl 50% dimethyl polysiloxane		From 45 to 240/260
  DB-225ms, DB-225	FAMEs, alditol acetates, neutral sterols	50% Cyanopropyl-phenyl 50% dimethyl polysiloxane	Polar	From 40 to 220/240	SP-2330, CP-Sil 43 CB, OV-225, Rtx-225, BP-225, 007-225
  HP-INNOWax	Alcohols, free organic acids, solvents, essential oils, flavors and fragrances	Polyethylene glycol	Polar	From 40 to 260/270	BP-20, 007-CW, CP-WAX 52 CB, Stabilwax, Supelcowax-10
  DB-WAX	Solvents, glycols, alcohols	Polyethylene glycol	Polar	From 20 to 250/260	Rt-Wax
  CAM	Amines, basic compounds	Polyethylene glycol-base modified	Polar	From 60 to 220/240	Carbowax Amine, Stabilwax-DB, CP-51 WAX
  HP-FFAP, DB-FFAP	Organic acids, alcohols, aldehydes, ketones, acrylates	Polyethylene glycol-acid modified	Polar	From 40 to 250	OV-351, SP-1000, Stabilwax-DA, 007-FFAP, Nukol
  DB-23	FAMEs (requiring cis/trans resolution)	50% Cyanopropyl 50% dimethyl polysiloxane	Polar	From 40 to 250/260	Rtx-2330, 007-23, SP-2330/2340/2380/2560
  CycloSil-B	Chiral compounds (general purpose)	30%-heptakis (2,3-di-O-methyl-6-O-t-butyl dimethylsilyl)-B-cyclodextrin  in DB-1701	Mid-polar	From 35 to 260/280	LIPODEX C, Rt-BDEXm, B-DEX 110, B-DEX 120
  HP-Chiral b Columns	Chiral compounds (using a Nitrogen selective detector, NPD)	beta-Cyclodextrin in phenyl-based stationary phase	Mid-polar	From 30 to 240/250	LIPODEX C, Rt-BDEXm, B-DEX 110, B-DEX 122
  PLOT Column Applications
  HP-PLOT Molesieve	Permanent and noble gases. Argon and oxygen separation at 35�C	5� molecular sieve zeolite		From -60 to 300	Rt-Molesieve 13X, Molesieve 5�
  HP-PLOT Al2O3 �KCl�	C1-C6 hydrocarbons in natural gas, refinery gas, fuel gas, synthetic gas, dienes	Aluminum Oxide "KCl" deactivated	Least polar	From -60 to 200	AluminaPlot, Rt-Alumina,CP-Al2O3/KCl Plot
  HP-PLOT Al2O3 �S�	C1-C6 hydrocarbons in natural gas, refinery gas, fuel gas, synthetic gas, dienes	Aluminum Oxide "Sodium Sulfate" deactivated	Mid-polar	From -60 to 200
  GS-Alumina	C1-C6 hydrocarbons in natural gas, refinery gas, fuel gas, synthetic gas, dienes	Aluminum Oxide with proprietary deactivation	Most polar	From -60 to 200
  HP-PLOT Q	Hydrocarbons including isomers, CO2, methane, air/CO, water, polar solvents, sulfur compounds	Polystyrene-divinylbenzene		From -60 to 270/290	PoraPlot Q/S, Rt-Q, Supel-Q PLOT
  HP-PLOT U	C1 to C7 hydrocarbons, CO2, methane, air/CO, water, oxygenates, amines, solvents, alcohols, ketones, aldehydes	Divinylbenzene/ethylene glycol dimethacrylate		From -60 to 190	PoraPlot U
  GS-GasPro	C1 to C12 hydrocarbons, CO2, trace-level sulfurs, hydride gases, inorganic gases, halocarbons, SF6,  oxygen/nitrogen separation at �80�C	Proprietary, bonded silica-based		From -80 to 260/300	CP-SilicaPLOT
  GS-CarbonPLOT	C1 to C5 hydrocarbons, CO2, air/CO, trace acetylene in ethylene, methane	Bonded monolithic carbon layer		From 0 to 360	CP-CarboBond
  Specialty Phases - Environmental Applications
  DB-624		6% Cyanopropyl-phenyl 94% dimethyl polysiloxane	Mid-polar	From -20 to 260C	Rtx-624, AT-624, SPB-624, CP-624, PE-624,007-624
  DB-VRX	Volatile Organic Compounds using MSD, ELCD/PID	Proprietary phase	Non-polar	From -10 to 260C	Rtx-VRX
  DB-35ms	CLP Pesticides, Chlorinated Herbicides, PCBs, 508.1 Pesticides	35% Phenyl 65% dimethyl arylene siloxane	Mid-polar	From 50 to 340/360C	MDN-35, BPX-35
  DB-XLB (Confirmation Column)	Proprietary phase	Non-polar	From 30 to 340/360C	No equivalent
  HP-5ms	Semivolatiles by EPA Method 8270	5% Phenyl 95% dimethylpolysiloxane	Non-polar	From -60 to 325/350C	SPB-5, XTI-5, Mtx-5, CP-Sil 8CB, SE-54, Rtx-5, BPX-5, MDN-5, Rtx-5ms
  DB-XLB	PCB Congener Analysis (209 Congeners) CLP Pesticides, Chlorinated Herbicides, PCBs, 508.1 Pesticides	Proprietary phase	Non-polar	From 30 to 340/360C
  DB-TPH	Leaking Underground Fuel Tank (LUFT) testing	Proprietary phase	Non-polar	From -10 to 290C
  DB-MTBE	MTBE in Soil and Water	Proprietary phase	Non-polar	From 35 to 260/280
  Other Specialty Phases
  HP-Fast GC Residual Solvent Column	Residual Solvents	6% Cyanopropyl-phenyl 94% dimethyl polysiloxane	Mid-polar	From -20 to 260C
  DB-ALC1	Blood Alcohol Testing	Proprietary phase	Mid-polar	From 20 to 260/280C
  DB-ALC2		Proprietary phase	Mid-polar	From 20 to 260/280C
  HP-Blood Alcohol Column	Proprietary phase		From -60 to 270/290
  *Temperature limits vary with column dimensions. Always confirm temperature limits prior to column use.