Dubois - IsA - Myths and Mistakes - Oct 6c, 2010 - IsA AW -CPAC Release

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Process Analytics:are there dinosaurs among us?

Myths and mistakes that maycontribute to our extinction

Rob Dubois

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Rob [email protected]

• Rob Dubois is a process analytical consultant based out of Sherwood Park, Canada. He has beenan active writer, presenter and visionary behind the use of smart and automated sampling.

• Rob co-authored (with Peter van Vuuren and Jeff Gunnell) the NeSSI Generation IIspecification which helped lay the groundwork for a dedicated sampling system bus for processanalytical. He has worked with major companies including Dow Chemical, ExxonMobil Chemicaland CF Industries and has been involved with process analytical for over 35 years with rolesranging from maintenance to sampling design, project engineering and R&D.

• Rob is dedicated to process analytical simplification as well as the use of microAnalytical devices.He has started a company to advance these concepts.

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Are we sick of this ‘mantra’ yet?

• 80% of process analytical reliability issues aredue to the sample system. – Poor understanding of sample integrity

– plugged, leaking, fouled?

– Poor understanding of sample temperature – condensing, frozen, two-phase?

– Poor understanding of sample pressure

– vent header fluctuation, perhaps?

• Let‟s take a „pipe to pixel‟ look at myths and

mistakes with process analytical systems

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Myth: analyzer rounds are essential

• today – Of $6 billion spent each

year on processanalytical, approx. 50% is

spent to maintain* – How many people in your

plant look after analyzers?

– Can automation help?

*Source: PAI partners

Diogenes searching for a hydrogen leak

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Myth: Size (and weight) don’t matter

conventional

• Size and weight are nota critical factor with

current design• High infrastructure costs

by-line

• Move closer to theprocess

• Size is important for fieldmaintenance

Conventional sample system designs can be

quite large and involved.

The move to by-line analysis requires smaller, lighter

components.

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Myth: the process interface meet our needs

• We do careful design of sample system components toreduce lag time, yet the 1st process connection canintroduced dead volume

• Redesigned each project – who owns these things!

• Or worse we give an operator a way to stop the flow

Let’s get an industry standard, low volume sample

valve and probe specifically designed for Process Analytical

requirements

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Myth: it’s de rigeur to use DB&B* valves

Cultural norm

• Based on historical problemswith leaking and/or bad valves

• Adds weight and cost

• Bubbler identify leaks

– Fugitive emission source

– Maintenance issue

With automation

• Pressure or flow sensor

• Close coupled design

• Simple on/off valves fine

“landry” loop

AT

* DB&B = double block & bleed

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Myth: Monitoring the analyzer is good enough(Actually the analyzer is only one part of a large system)

SampleSystem Analyzer

Extract & Pre-Condition

Transport

DCS

Utilities

Shelter/House/Enclosure/Container Services &Utilities

Post cond. &disposal

Validate

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Myth: Div/Zone 2 rating is fine for

enclosures handling hazardous fluids

• Enclosures handling hazardous fluids should be “defacto” treated as Div/Zone 1

– “sniff test”

• Not a myth: It‟s difficult and expensive to automate an

analytical system in order to meet multi-nationalhazardous area requirements. Global harmonizationwelcome!!

The penitent

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Myth: 4-20 mA & discrete I/O is the

communication choice for sample systems

• It‟s labour, design and costintensive for use with a multitudeof geographically distributedsensors & actuators in hazardousareas

• Emerging…

– Small, serial bus rated Div/Zone 1

– Capable of 20-30 sensors per node

– Intrinsically safe NeSSI-bus (CAN, I2C)

System designed with conventional 4-20

mA and discrete I/O in a hydrocarbon

processing facility. (Courtesy of Dow

Chemical. Photo by R. Dubois)

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Demonstration of a CAN based sampling

system at ISA EXPO2007. Houston, Texas.(Photo by R. Dubois)



Myth: Automation done in the DCS

• Better – a local way to handle our signals

• Unmet need the SAM* (real distributed, local control)

– Form “hockey puck” size, Div/Zone 1

– Function PAC** like; serial I/O

– Graphical visualization

– Standard “applets” (e.g. stream switch, system health, etc.)

© Danielle R. Dubois

“Who can solve SAM?”

SAM

*SAM = Sensor Actuator Manager

**PAC = Process Automation Controller

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Programmable Substrate Heater

Myth: Wireless – not on my watch!

V

P

A

F SAM

NeSSI™-bus

Wireless*or wired access

Auxiliary Heating/Cooling

SubstrateT

T

DCS (Operations)

Ethernet LAN (“anLAN”)

(wired today; wireless future)

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Secure, remote connectivity

for maintenance is important!

- Wireless may be useful for

this purpose



Myth: Thermostats are good enough

conventional

• On/off control typ.

• Blind & dumb

• Dew point problems

automated

• Graphical visualization

• Networked control of heat

tracer, heater, regulator • Dew points and flashes

tightly controlled

Heating systems need to be

tied into a bus system so that

they can be set and viewed

locally or remotely.(Courtesy of Intertec)

The ubiquitous Honeywell thermostat

common to home heating systems. An

explosion proof variation is typically

used with analytical systems.

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Myth: Rotameters, etc. rule (not)

• conventional – Rotameters, pressure and

temperature gauges whichrequire walk-by visual

checking• automated

– Temperature, flow andpressure gauges replaced

with bus-enabled sensors – Graphical visualization

– “Window test”Rotameter replacement: NeSSI-bus-enabled sensor

can measure fluid flow, pressure and temperature,

and serve in Div/Zone 1. (Courtesy of CircorTech)

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Myth: No need to automate flow control

conventional

• Remote pilot valveslocated in a safe area

– Eliminate tubing runs• Needle valves still used

to control pressures andflows

automation

• Bus-enabled solenoidvalve pilots rated for

hazardous areas – Some progress!

• Needle valves replacedby proportional valvesimilar to EPC* in gaschromatographs – So far no productValve control module,

NeSSI-bus enabled.(Courtesy of Swagelok)

*EPC = electronic pressure control

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Myth: Operators need detailed operational

information

• Common practice – Status alarm of analyzer & flow perhaps

– No mechanism to predict failure

• Better

– RED: Analytical system bad – unreliable data – YELLOW: Analytical system needs maintenance

– GREEN: Analytical system good – reliable data

• Give operators a system reliability indication

– “watch test”

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Myth: microAnalytical – easy to deploy

• The reality…it‟s tough – Certifications & hazardous classifications

– Sample systems & analyzer houses

– Reliability

– Interferences and sensitivity – Expensive

– A conservative end user community

– It takes years to penetrate this market

• Is there a simpler way…?

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Menacing complexity! Statue

dedicated to Kafka – Prague,

Czech Republic



Analytical Engine – are we heading in the

right direction?

• Miniscule sample used

• Integral pressure, temperature control

• Integral filtration; particulate rejection

• microAnalytical ready

• Sample returned to pipe (no venting req.)

• Based on a patent awarded to Dow Chemical

• Complete analytical solution by-line

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Myth or not? Process analytical - the

technology of last resort

• Unless we become morereliable and lower cost wemay become extinct

• We can improve reliability

incrementally throughautomation, but are we justapplying a band-aid?

• What then, needs to done to

move our analyticalmeasurements by-line?

Analyzer installation – Buna, Germany ca. 1951

Courtesy of S. Bach

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Dubois - IsA - Myths and Mistakes - Oct 6c, 2010 - IsA AW -CPAC Release

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