Over the last five years, process fluid analysis has moved from the laboratory out onto the plant, from a manual assessment to a field transmitter, with digital intelligence and communications
On-line analysers, whether for liquid or gas flow-streams, have come of age over the last five years.
Driven by customer demand, process fluid analysis has moved from the laboratory out onto the plant, from a manual assessment to a field transmitter, with digital intelligence and communications.
Typical customer criteria have been: * Develop rugged and reliable field mountable devices - analytical "transmitters".
* Eliminate the need for sample handling systems - or reduce their complexity, to improve reliability and process control performance/response time.
* Embed digital intelligence in the analyser to allow it to talk via conventional fieldbus systems and interface to Asset Management software.
* Conform with all existing and impending world-wide performance and safety standards, such as CE and ATEX. * Simplify, or demystify, the procedures of process analysis. These demands have led to significant product developments and improvements - to provide a product range from Rosemount Analytical that addresses these customer requirements. Historically pH measurement was the domain of the site chemist. Developments have simplified the base sensor, to produce it as a one piece, moulded combination electrode, with a built-in amplifier.
With no co-axial cables required, the sensor is now available with a Variopole 6.0 connector, for simple installation; and it has integral automatic thermal compensation. The Uniloc Division of Rosemount Analytical has also introduced steam sterilisable sensors for pH measurement, suitable for plants where SIP cleaning is necessary.
Also available is special mounting hardware, for automatic sensor retraction, cleaning and calibration, or sensor pressurization systems.
The Analyser electronics has also been simplified.
Taking the lead from field mounted pressure transmitters, the first field mounted IP66 intrinsically safe pH transmitter looked similar, and was called the "1181".
Developments followed with HART transmitters, and then Foundation fieldbus compatible transmitters, which monitor and report on reference electrode impedance to detect coated or contaminated electrodes.
The Rosemount Analytical 1055 panel or control room wall mounted electronics unit is a universal monitoring and alarm system for pH sensors, DO cells, chlorine or ozone electrochemical cells, or for conductivity measurement sensors.
The single unit simplifies life for the plant engineer, with only one style of unit whatever the sensor.
On the two channels available it can monitor any of the above sensors - even two different sensors into the same unit.
Again simplicity is the keynote - four Quick-Start key strokes initiate the operation.
Relay outputs provide high or low alarms, plus alarms to USP23 and 24 requirements if needed for water conductivity measurement.
Oxygen analysis is used for the combustion control of boilers and process heaters - too little or too much oxygen reduces energy efficiency.
The measurement is best made in the stack - it leads to better control and avoids complex, and maintenance intensive, sample handling.
The only way to do this is by using a Zirconium Oxide based oxygen sensor - a technology invented by Rosemount Analytical.
Like so many analysers, early stack oxygen probes required bulky electronics mounted remote from the sensor.
Rosemount pioneered sensor mounted electronics with the Oxymitter.
This "transmitter" is equipped with HART or Foundation fieldbus communications, diagnostics, validation and auto calibration facilities.
It provides superior performance and value over traditional oxygen analysers through demonstrably reduced capital and operating expense.
To many people gas chromatography is the ultimate in analytical black magic! While arguably the most deserving of "demystification" - it is probably the most difficult to turn into a transmitter. Rosemount engineers rose to this challenge and developed the GCX - a design which is approximately one third the size of conventional GC's, uses no instrument air and, being Cenelec/IP65, can be mounted directly on the process.
This saves capital and operating expenses while giving many process control benefits.
Just the savings in instrument air can justify the investment! Such a transmitter was proved through the winter of 1998/99 on an ARCO British gas production platform in the North Sea - with no special instrument housing to protect it from the elements.
The unit there is configured as a 3 stream analyser: remote monitoring is achieved via up to 6 separate 4-20mA outputs, H1 Foundation fieldbus, redundant high speed Ethernet communication and an intuitive Internet/Web browser HMI.
Is there light in the process? "No moving parts, no sample handling please" - this was the customer request.
Rosemount achieved that with both the Near Infra Red and Laser Raman process spectrometers.
Measurements are made by shining light into or across the process fluid - inside a pipe or vessel, through a window, using fibre-optic light guides.
The spectrometer measures the effects that the composition of the fluid has on the "light out compared to light in" - true simplicity and demystification! These techniques have no moving parts whatsoever - a real advantage when it comes to measurement reliability for process control.
Unique applications have included the control of polymer production (Raman), and of sterilisation processes in the pharmaceutical industry (NIR).
The radical changes of the last five years have only accentuated the demands from customers for more information, simpler field sensors, and more on-line capability.
New developments are coming to market at an ever increasing pace.
This is backed up by more information available to support the customer - manuals and service instruction information on the suppliers' websites, but also investment from suppliers like Fisher-Rosemount in the sales interface team, both in the factory and in the field.
Partnerships have developed from closer customer contact, which has led to further product developments and innovation.
The next five years are likely to be more exciting than the last five!
