High temperature | Hydrogen (H2) gas analyzer | Thermal conductivity

Features and typical applications

High temperature thermal conductivity Hydrogen process gas analyzer - CONTHOS 3 – TCD HT

Key Features

High temperature analyzer with thermostat controlled gas paths up to 180°C for high dew points
High temperature analyzer up to 180°C to avoid possible salification
Extremely long term stable analysis of H₂ in binary and quasi-binary gas mixtures
Ultra-fast response T₉₀ ≤ 3 sec
Highly corrosion resistant TCD cell with Al₂O₃, glass and quartz for process gases with Cl₂, HCl, H₂O or NH₃, CO₂, H₂O and H₂

Typical Applications

Metallurgical process gases such as nitration and nitrocarburizing
Heat treatment & hardening with hydrogen, ammonia and carbon dioxide
Chemical processes with hydrogen as well as acidic and alkaline components
Monitoring of processes with hydrogen, water vapor and high dew points

Description

The CONTHOS 3 TCD HT is a high temperature thermal conductivity gas analyzer specially developed by LFE for on-line monitoring based on extractive methods for hot and wet gas analysis in process industry applications.

The special outstanding technical features of LFE's high temperature gas analyzer are:

High temperature resistance and thermostat control of all gas paths being in contact with the sample gas - thermostat control from 70°C to max. 180°C
High temperature version of thermal conductivity detector - thermostat controlled temperature from 70°C to max. 180°C
Control of the heated gas paths in the analyzer including alarm signals for the safe compliance with a minimum temperature for hot gas analysis
High corrosion resistance in the entire sample gas path
Extraordinarly high long-term stability
Intuitive user-interface based on NAMUR recommendations
Optional dynamic interference correction of up to 3 gases in conjunction with external, selective gas analyzer channels

The technical features of the CONTHOS 3 TCD HT gas analyzer open up new areas of application for the thermal conductivity principle for measurement of hot and wet sample gases where “cold” extractive analysis methods cannot be considered.

The high temperature version includes the complete thermostat control of the TCD detector as well as all gas paths and connectors within the analyzer for temperatures above the sample gas dew-point in conjunction with external heated gas lines for gas inlet and gas outlet.

The LFE CONTHOS 3 TCD HT gas analyzer has proven itself in many years of continuous operation of hot extractive gas analysis in fields such as:

in corrosive process gases in the chemical and petrochemical industry
in thermostat controlled applications with high dew-points
in thermostat controlled applications avoiding the formation of salts through acidic and alkaline sample gas components

LFE's Thermal Conductivity Detector (TCD)

In conventional gas analyzers utilizing the principle of thermal conductivity a heated object is suspended in a volume containing the sample gas. Electrical energy passed through the object results in the object heating up and attaining an equilibrium temperature which is primarily dependent upon the thermal conduction properties of the surrounding gas. This temperature is normally measured directly as a change in the electrical resistance of the heated object itself.

LFE´s unique principle modifies this "classical" method by spatially and electrically decoupling the heated element from the temperature sensing element. The specially designed geometry of the TCD cell in conjunction with the decoupling effectively suppresses undesired competing thermal effects (i.e. free and forced convectional effects). The result is an instrument whose quick, stable response requires no compromise between gas flow and response time.

Features

micro-miniaturized for quick response behavior
corrosion and temperature resistant
made of aluminum oxide (Al₂O₃), glass and SiO_x-coated platinum sensor filaments

Model variations

Technical data

Technical Data

Enclosure & Electrical Data

	CONTHOS 3E 19”-rack housing	CONTHOS 3F field housing	CONTHOS 3F - Ex p ATEX compliant Ex p system	CONTHOS 3F - HT high temperature version
Technical specifications subject to change without notice

	for mounting in 19" cabinet	purgeable steel housing for wall mounting; with separate compartments for the electronic components and the analytical components
Enclosure & electrical data
Dimensions (H x W x D)	133 x 483 x 427 mm (3U / 84HP) 434 x 460 x 270 mm		490 x 460 x 270 mm	502 x 460 x 270 mm
Protection class	IP40	IP65
Electrical hazardous area class			Protection type "px" for zones 1 & 2 according to EN 60079 Ex protective class of system: II 2 G, Ex p II T4
Weight	approx. 10 kg	approx. 25 kg	approx. 30 kg	approx. 25 kg
Power requirements	100-240 VAC (48-62Hz; nominal voltage range: 88-253 VAC; 100 VA max. during warm-up period)

Measuring Characteristics

Common Technical Data CONTHOS 3E \| CONTHOS 3F \| CONTHOS 3F - Ex p \| CONTHOS 3F - HT
Technical specifications subject to change without notice
Measuring characteristics
Measuring principle	Thermal conductivity (TCD). Difference in thermal conductivity (Δλ) of various gases
Measuring ranges	Up to 3 linearized, independently configurable, switchable ranges. Suppressed output ranges within the corresponding reference range can be easily configured. Range switching is accomplished manually, automatically and/or remotely via optional digital inputs. lowest range: 0 - 0.5% H₂ in N₂ or 99.5-100% H₂ in N₂ (or equivalent Δλ) largest range: 0 - 100% H₂
Calibration	Manual: 2-point (zero / span) calibration Option: automatic or remote calibration in conjunction with the optional digital I/O-board or Modbus interface (RS-485 or TCP)
Warm-up time	dependent upon TCD operating temperature as well as the ambient temperature: 70°C: approx. 20 min.; 180°C: approx. 90 min.
Response time t₉₀	≤ 3 sec (at 60 l/h gas flow and minimum signal dampening level)
Influence of gas flow	between 3 - 30 l/h: < 0.5% of range span for a gas flow change of ±10 l/h between 30 - 60 l/h: < 1% of range span for a gas flow change of ±10 l/h Higher flow rates up to e.g. 120 l/h are possible. At these higher flow rates it is recommended that the analyzer be calibrated at the operating flow rate.
Pressure influence	The TCD principle has a normally negligible pressure dependency. At very low ranges it can be seen as a proportional signal offset. Gas specific order of magnitude: < 0.02% H₂ equivalent per 100 mbar
Detection limit ¹	≤ 0.5% of span (at signal dampening level: 1 sec)
Linearity/ Accuracy ¹	≤ 0.5% of span
Reproducibility ¹	≤ 0.5% of span
Response drift ¹	Zero: ≤ 1% of span per week Span: ≤ 1% of span per week
Ambient temperature influence	Zero: ≤ 1% of span per 10 K Span: ≤ 1% of span per 10 K
Ambient temperature in operation	allowed temperature range : +5 to +45°C
Influence of inclination	no influence

Materials

	CONTHOS 3E 19”-rack housing	CONTHOS 3F field housing	CONTHOS 3F - Ex p ATEX compliant Ex p system	CONTHOS 3F - HT high temperature version
Technical specifications subject to change without notice

Materials in contact with sample gas
TC Detector	Al₂O₃-ceramic and sapphire, glass and SiO_x-coated Pt measuring filaments high corrosion and temperature resistance
Internal gas lines	Standard: PTFE / PFA Optional: stainless steel tubing (SS 321; similar to 1.4541) and 1.4571	Standard: PTFE / PFA Optional: stainless steel tubing (SS 321; similar to 1.4541)	Stainless steel tubing (SS 321; similar to 1.4541)
Sample gas connectors	Standard: stainless steel (SS 316; similar to 1.4401) Standard: Swagelok^® connectors for ø6mm tubing
	Optional: Swagelok^® connectors for ø¼" tubing Optional: NPT ¼" (female)	Optional: Swagelok^® connectors for ø¼" tubing		Optional: Swagelok^® connectors for ø¼" tubing
	Optional : PFA connectors for synthetic tubing DN 4/6 (only in conjunction with PTFE tubing)

Instrument Interface

Common Technical Data CONTHOS 3E \| CONTHOS 3F \| CONTHOS 3F - Ex p \| CONTHOS 3F - HT
Technical specifications subject to change without notice
Data display, inputs and outputs
User Interface	LC-display (40 characters x 16 lines) + bar graph Plain text description of instrument status as well as digital status output Language: switchable between English & German
Analog signal output	2 independently configurable, galvanically isolated analog outputs (with common ground; R_Load = 600 Ohm max) Available output levels: 0 - 20 mA, 4 - 20 mA, 4 - 20 mA with superimposed instrument status (NAMUR NE 43 compliant) as well as test signal levels (0, 4, 10, 12 & 20 mA)
Digital outputs 1 to 3 (instrument status)	Instrument status (NAMUR NE 107 compliant) via floating contacts (28 V max.; 350 mA max.) FAILURE (DO 1) \| MAINTENANCE REQUIRED (DO 2) \| FUNCTION CHECK (DO 3)
Analog inputs (optional)	3 galvanically isolated, configurable analog inputs for interference correction 0 - 20 mA or 4 - 20 mA (R_i = 50 Ohm)
Interference correction	3 correction channels for static and/or dynamic interference correction (dynamic correction only in conjunction with the optional analog inputs or Modbus interface (RS-485 or TCP)
Digital I/O (optional)	Digital inputs: 8 configurable, optically isolated inputs (6 - 24 VDC; 10 mA max.) remote range selection remote triggering of zero and span calibration remote triggering and cancelling of automatic calibration switching of interference correction analog inputs to a secondary input range mapping of user defined input to a digital output Digital outputs: 7 configurable, floating relay contacts (28 V max.; 350 mA max.) threshold monitoring (1 threshold per measuring range) feedback as to the current range calibration gas selection mapping of user defined input to a digital output
Modbus interface (optional)	Modbus RTU - RS485 Modbus TCP
Service interface	non-isolated serial interface for accessing the instrument's configuration via a proprietary PC software

¹ at constant temperature and pressure

The stability data is valid for analyzer operation with pure bottled gases. Instrument accuracy is based on binary or quasi-binary gas mixtures. Deviations from the above data can occur in conjunction with process gases depending upon the gas quality and the degree of gas handling.
Unless otherwise specified the CONTHOS gas analyzer is neither ex-proof nor intrinsically safe in terms of explosion protection.
The CONTHOS may not be employed for the analysis of ignitable gas-mixtures. The customer must ensure compliance with applicable regulations when using the analyzer with inflammable or toxic gases or when installing within explosion endangered environments.
The customer must ensure that the sample gas is dry and free of particulates.

CONTHOS 3 - TCD HT

Features and typical applications

Key Features

Typical Applications

Description

Description

LFE's Thermal Conductivity Detector (TCD)

Features

Model variations

Model variations

Options

Technical data

Technical Data

Enclosure & Electrical Data

Measuring Characteristics

Materials

Instrument Interface

Downloads

Downloads

CONTHOS 3-TCD | Thermal Conductivity Gas Analyzer

Application Questionnaire

Brochures

Product Data Sheets

CONTHOS 3

Sample Applications