Michell Instruments Promet I.S Specifications

Process Analyzers

Promet I.S.

Process Moisture Analyzer

Promet I.S. Process Moisture Analyzers are heavy duty, industrial hygrometer systems for
measurement of high pressure, process gases and vaporized liquids on natural gas platforms and
terminals, petrochemical plants and industrial gas manufacturing facilities. Promet I.S. combines
Michell’s proven ceramic moisture sensor with sample conditioning system design engineering
capabilities to provide a reliable and easy to operate, multi-channel on-line instrument for both

ammable and non-ammable gases.

Highlights

• Simple, cost ecient operation and low-maintenance

• Immune to chemical attack from H2S, mercaptans
and other sulphides

• Protected against glycol or other liquid contaminants

• Accurate direct dew-point measurement at process
pressure up to 45 MPa (450 barg)

• Moisture range from ambient to ppb level with
exhaustive list of hygrometric units, including key
parameters of natural gas

• Two 4-20 mA congurable outputs and digital
Modbus RTU based communication.

• Assured calibration integrity traceable to NPL (UK)
and NIST (USA)

• User programmable or real-time active pressure
compensation for moisture content calculation

• Multichannel with up to 4 independent measurement
channels

www.michell.com

Applications

• Natural gas production and processing

• Pipeline drying

• Oshore export pipeline natural gas

• Transmission pipeline monitoring

• Fiscal metering of gas

• Gas storage facilities

• Renery recycle gas – reformer and platformer

• LNG production processing and receiving terminals

Process Analyzers

Michell Promet I.S.
Process Moisture Analyzer

Michell Promet I.S. is a rugged on-line instrument tailored to

customers’ specic application and technical requirements.

Measurements can be made across a wide range from -100 to
+20°C dew point with an accuracy of ±1°C dew point and at
process or pipeline pressures up to a maximum of 45 MPa.

The rack-mounted Promet I.S. Control Unit provides real­time two-line display of moisture content/dew point and
pressure, user settable alarms together with analog output and
digital communications, conveniently located in a safe area.
Intrinsically safe sensors, with a sampling system, are installed
in the hazardous zone to minimize sample transportation time
and ensure fast response to process moisture changes.

The Control Unit in the multi-channel MCU format can also
include moisture in liquid analysis function by combining with
Liquidew I.S. Moisture in Liquid Analyzer.

Calibration integrity for accurate measurement

The Promet I.S. Ceramic Moisture Sensors are individually
calibrated down to -100°C dew point/10 ppbV. This avoids the
common problems associated with other trace moisture solution
providers of lack of calibration integrity at trace moisture levels
together with low end drift to the dry and failing to respond to
increase in process moisture condition after extended period of
‘desiccation’.

All Michell moisture probe calibrations are traceable to the
humidity standards of leading international metrology institutes,
NPL (UK) and NIST (USA), so assuring correct measurement of
the moisture in your process.

Measurements at line pressure made easy

The Promet I.S. features moisture content calculation with user
input analysis pressure but, in applications where pressure
varies, the real-time pressure sensor signal provides more
accurate, active compensation for moisture content conversion.
(Pressure sensor optional.)

Features

Multi-Channel Unit

Reliable measurement

Michell’s process industry-proven moisture sensor used in the
Promet I.S. is exceedingly durable. Chemically inert materials
coupled with physical resilience provide long-term reliable
service in process measurements of up to 45 MPa, enabling
measurement directly at process/pipeline pressure. The sensor
is protected against glycol and other process borne liquid
contaminants as well as immune to chemical attack from H2S,
mercaptans and other sulphides.

Easy to use with complete functionality

The 19” sub-rack mounting Promet I.S. Control Unit is simple
to operate. The bright alphanumeric LED display with optional
live pressure compensation provides unit conversions from dew
point to an exhaustive list of moisture content units, so the

user has exibility to select the preferred hygrometric unit. The
conversion method is for ideal gases and also specic to natural

gas, using either the long established IGT Research Bulletin No.
8 or the more recently published ISO 18453, to customer order
preference.

The front panel interface, enables the user to scroll through

the set-up menus to easily congure the analyzer to their

own requirements. Four user-adjustable alarm points and two
analog 4-20 mA outputs are provided as well as a digital RS485
RTU for connection to external devices.

Superior measurement stability

To ensure continuous optimum performance, the Promet I.S.
sampling system is internally temperature controlled. This

greatly reduces the eect of potential temperature variations

that would otherwise introduce transitional adsorption and

desorption eects in the sampling system components

and result in erroneous measurements during periods of
temperature change. Best practice also dictates that sample
line tubing should be maintained at an elevated temperature,
so for customer convenience, self limiting heated tube bundle
is available as a factory option for Promet I.S. sampling system.

Certied intrinsically safe

Promet I.S. sensors and sampling systems are designed for

ammable and non-ammable gas within hazardous areas.
ATEX certied by EECS for use in hazardous areas to II 1G EEx

ia IIC T4. Complete packages conforming to NEC Class 1 Div

1 or IECEx certications are also available. Promet I.S. carries

GOST pattern approval and GOST Ex.

Simple to maintain with a sensor calibration exchange
program

For Promet I.S., calibration maintenance is simple. The unique

Michell Calibration Exchange Service oers fast, world-wide
delivery of replacement ceramic sensors certied traceable to

metrology standards of NPL and NIST. As the calibration data
for the sensor is factory programmed into on-board non-volatile
memory, no programming or data input is required by the
user to complete the calibration process. Fitting a Calibration
Exchange Sensor renews the calibration, with minimal down­time. The Calibration Exchange Service facilitates a professional,
scheduled user QA programme at a lower cost than a traditional
‘return to manufacturer’ recalibration service.

www.michell.com

Process Analzyers

Permeable Gold film

Hygroscopic Mono-layer

Base Electrode

Ceramic Substrate









Moisture
Molecules



Advanced Sensor Technology

Flexible conguration. Total analyzer system tailored
to specic customer requirements

Promet I.S. is available in a multi-channel format (MCU). This
MCU enables up to four measurement channels within a single
19” sub-rack unit. The Promet I.S. channels can be combined
together with a sister product for moisture in liquid analysis,
Liquidew I.S., into an MCU to enable both gas and liquid samples
measurement with a single analyzer system. With the MCU,
each measurement channel functions totally independently, so

that any maintenance on one channel will not aect the others.

Customers can also order blank channels for future expansion.

The Promet I.S uses the rugged Easidew PRO I.S. sensor,
allowing the transmitter to be installed directly outdoors.

Best practice sampling systems

The design of the Promet I.S. Premium Sampling System has
drawn on Michell’s 35 years of expertise in on-line process gas

analysis. There are two core congurations:

• The Natural Gas Processing and Transmission Sampling

System uses the most advanced ltration techniques with
microporous membrane and continuous by-pass ow to

remove and dispose of all liquid phase contaminants. A
glycol adsorption cartridge removes residual glycol vapour
carried over from the dehydration process.

Promet I.S. utilizes Michell Ceramic Moisture Sensor, oering

unrivalled reliability and performance with more than 1,000
installations in natural gas and petrochemical sites world-wide.

The Michell State-of-the-art thick- and thin-lm semiconductor

technology produces an exceedingly durable sensor, with
superior measurement sensitivity to 10 ppbV moisture content
and high-pressure capability up to 45 MPa (450 barg).

Unlike older aluminium-oxide technologies, the inherent
immunity to pressure shock of the Ceramic Sensor completely
avoids any risk of sensor failure at commissioning or shut­down, whilst the unique inert nature of the sensor gives
unrivalled long-term resistance to chemical attack, even in
extremely sour gas with percentage level H2S concentrations.
The microprocessor electronics unit in the sensor stores
the sensor calibration data and provides a stable linear
4-20 mA output over the wide dynamic °C dew-point range. All
Michell Ceramic Moisture Sensors provide up to 1°C accuracy
and excellent long-term stability in process applications. The
unique Michell Calibration Exhange service enables all our

customers worldwide to maintain traceable certied calibration

of our process moisture analyzers at modest cost and with
minimal spare stock and down-time.

The Ceramic Sensor responds to the partial pressure of water
vapor in the gas being measured, which is directly related to the
dew-point temperature. Every Promet I.S sensor is calibrated
against fundamental dew-point measurement systems in
Michell’s world class laboratory, which is internationally
accredited and directly traceable to both NPL (UK) and NIST
(USA) base standards.

• The Trace Moisture in Hydrocarbon Gas Sampling System
is for trace moisture measurement after the molecular
sieve dehydration process which is also suitable for many
other monitoring applications at ppm and sub-ppm levels

in renery gases and critical petrochemical processes.

A minimalist approach to the sampling system design is
essential to ensure best dynamic response to process

moisture variations. A particulate lter and isolation valve

are the only components prior to the sensor.

Permeable Gold film





Hygroscopic Mono-layer

Base Electrode



Ceramic Substrate



Moisture
Molecules

Structure of the Michell Ceramic Moisture Sensor

Promet I.S Sampling system



www.michell.com

Operation of the Michell Ceramic Moisture Sensor

Process Analyzers

Technical Specications

Sensors

Sensor technology Michell Ceramic Moisture Sensor

Sensor version Easidew PRO I.S.

Measurement range -100 to +20°Cdp

Calibration range -100 to +20°Cdp

Calibration Traceable to British (NPL) and American

Accuracy Dew point: ±1°C between –60 and +20°Cdp

Resolution 0.1°C between +20 and -100°Cdp

Analysis pressure Up to 45 MPa (450 barg)

Operating temperature -40 to +60°C

Sample ow rate 1 to 5 Nl/min

Optional pressure sensor 0-138 barg (other ranges available)

(NIST) National Humidity Standards

Moisture content: ±10% of reading
Dew point: ±2°C between -60.1 and -100°Cdp

Accuracy: ±0.25% FS

Certication

Hazardous area

certication

Pattern approval GOST-R, GOST-K

ATEX: II 1 G Ex ia IIC T4 Ga (–20°C to

+70°C)

IECEx: Ex ia IIC T4 Ga (–20°C to +70°C)

TC TR: 0Ex ia IIC T4 Ga (–20°C to +70°C)

FM: Class I, Division 1, Groups A B C D, T4

CSAUS: Class I, Division I Groups A B C D, T4

C

Control Unit

Display Two line 6-digits LED, displaying moisture

Analogue output Two 4-20 mA (max. load 500 Ω) one output

Digital output RS485 Modbus RTU

Display mode Moisture content (ppmV)

Pressure compensation Fixed value (user programmed) or dynamic

content / dew point (user toggle) and analysis
pressure

congured for parameter, unit and range.

Second output set for sample pressure.

Moisture content in natural gas (ppmV,
LBMMSCF, mg/m³)
Dew point (°C or °F)
Pressure (psig, barg)

input from optional pressure sensor

Display resolution 0.1°Cdp, 0.1°Fdp, 0.1-0.001 ppmV ideal gas

Alarms Four alarm relays. Control action and setpoint

I.S. barriers Galvanic isolation type, integrated to Control

Power supply 85-265 V AC 50/60Hz or 10-72 V DC

Interconnection cable General instrument type, twisted pair,

Enclosure 19” sub rack unit

Operating environment Indoor, safe area, 0 to +50°C, < 90% RH

(adjustable), 0.01 ppmV natural gas, 0.01
mg/m³, 0.01 LBMMSCF, 1 psig, 0.1 barg

are user programmable
Two Form C contacts rated 10 A, 240 V AC or
8 A, 24 V DC. Non-inductive load
Two Form A contacts rated 5 A, 240 V AC or
4 A, 24 V DC. Non-inductive load

Unit

10 W max. power consumption

screened, single pair (two pairs with pressure
sensor)

Dimensions 132 x 483 x 375mm (h x w x d)
(100mm minimum clearance depth for cables
and vents)

Premium Sampling Systems

Enclosure 304 stainless steel (EN1.4301) enclosure;

Enclosure mounting Stainless steel wall mounting brackets

Enclosure ingress
protection

Enclosure temperature
control

Heater power supply 110/120 or 220/240/255 V AC, 47/63 Hz.

Operating environment Shaded position, on or o shore, -20 to

Option for complete enclosure in 316
stainless steel (EN1.4401); All xtures

stainless steel; Galvanised steel internal
mounting plate; Open panel version available
for indoor installation

Dimensions 800 x 600 x 300mm (h x w x d)

IP66

Heater/thermostat options for xed set-point

+20°C or adjustable set-point range 0 to
control 50°C

Power consumption 100 W max.

+50°C (-40 to +60°C max transient)

Enclosure cooling option recommended for
climatic ambient > +45°C

Michell Instruments 48 Lancaster Way Business Park, Ely, Cambridgeshire, CB6 3NW
Tel: [phone], Fax: [phone], Email: [e-mail], Web: www.michell.com/uk

Michell Instruments adopts a continuous development programme which sometimes necessitates specication changes without notice.
Issue no: Promet I.S_97150_V5_UK_0719

© 2019 Michell Instruments