Elemental CHNSO (CHNOS) analysis for determination of carbon, hydrogen, nitrogen, sulfur and oxygen content in petroleum products, biofuels, and more. CHNSO (CHNOS) elemental analyses from Intertek is available for a wide range of products and materials.

1. CHNS/O analyzer
By
Dr. S. PUGALENDHI, Emeritus Professor
Dr. P. VIJAYAKUMARY, Assistant Professor
Er. T. AYISHA NAZIBA, II-M.Tech.(REE)

2. Importance of ultimate analysis
 Organic Elemental Analysis (OEA)
Determination of Carbon, Hydrogen, Nitrogen, Sulfur and Oxygen in every type (organic and inorganic) of
materials
 Inorganic Elemental Analysis
Determination, of As, Sb, Pb, Ni, Cr etc. by, for example, Atomic Absorption

3. Instrument Components
 Front Panel
 Rear Panel
 Top Panel
 Furnaces Compartment
 Fixing Plates for the Reactors
 Fittings for Gas Connections
 Detector Compartment
 Description of the Detection system
 Electrical Compartment
 Connections Panel
 Transformers Compartment
 Synoptic Panel
 Autosamplers
 Manual Injection Device for Liquids

4. Basic steps in Elemental Analysis
 Quantification of the sample Weighing
 Quantitative oxidation of the sample Combustion
 Reduction of combustion gases Reduction
 Separation of the oxidation gases Chromatography
 Generation of the analog signal Detection
 Analog to digital conversion Integration
 Correlation of digital data to Calibration / Calculation
 Sample composition

5. Structure of the Instrument
The Units Constituting the Instrument
The instrument, in its different configurations, consists in a single structure subdivided into two
sections:
 Analytical Section
 Control Section

6. Analytical Section
 It comprises the following major components:
Furnaces
 Each furnace consists of a candle surrounded by an electrical resistor. The candle is plunged in a
refractory material housed in a metal compartment.
Furnace Temperature
 The temperature is monitored by a thermocouple appropriately located in the furnace.
Furnace Cooling
 The cooling time varies according to the operating temperature setting.
 The Flash 2000 analyzer can be equipped with one or two furnaces according to the instrument
configuration.
Thermal Conductivity Detector (TCD)
 It is located in a thermostatic chamber at controlled programmable temperature. This chamber also
accommodates the analytical column.

7. Chromatographic Columns
 The chromatographic column performs the chromatographic separation of the reaction products
generated during the combustion or pyrolysis process.
 The column can be kept at room temperature, or it can be placed in the thermostatic chamber of
the TCD detector according to the instrument configuration.
 The CHNS-O and CHN-O instrument versions use two analytical columns placed inside the
thermostatic chamber.

8. Adsorption Filters
 They can be made of glass or Plexiglas according to the analytical configuration.
Reactors
 These are tubes made of quartz or special alloy filled with different materials according to the
analytical configuration.
Autosampler
 It performs the automatic injection into the reactor of samples.

9. Control Section
The control section consists of two major components:
Pneumatic Compartment
 It consists of two pressure reducers, two pressure gauges and of several lines fitted with an
thermoregulator electronic flow controller (EFCt), which ensures the switching between helium and
oxygen, and controls the flow values.
Electronic Compartment
 It comprises the electronic boards for the instrument power supply and control.

10. Analytical conditions maintained for CHNS/O
determination
 Oxidation furnace temperature = 1200C
 Reduction furnace temperature = 950C
 Oven temperature = 65C
 Filament temperature = 190C
 Carrier gas = Helium
 Total run time = 720 s
 Sample preparation = Oven dried and ground
 Particle size = 0.2-0.5 mm in diameter
 Sample weight = Approximately 3 mg
 Inlet port for Helium = 250 kPa (2.5 bar)
 Inlet port for Oxygen = 250-300 kPa (2.5-3 bar) according to
the instrument configuration

11. CHNOS analyser