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Good, better, best

2 June 2011 No Comment

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Talking to a major cement producer recently, one comment really stood out for me: “We’ve learned to operate the plant in a whole new way. Turns out we were turning the handle the wrong way – we needed to push up power [a measure of throughput] to an absolute maximum. Before, we thought lower was better.”

Process optimization is a universal issue that can be constrained by many factors – hardware perhaps or limited CAPEX, maybe even the skill set within your team or the connectivity of your control software. Too often though, it is about having the right information and understanding to really push the process in a particular direction. Removing a constraint opens up a new operating window and the opportunity to move to a ‘better’ optimum.

In my first blog, I promised to explore how efficient process analytical technology delivers financial return. I want to paint a picture of how life changes when you install the right measurement system, the way such a move takes away the block on information flow and delivers the understanding that prompts comments such as the one above.

But first things first…

How often must we measure a process to get enough information to properly understand and optimize it? Well, the answer depends on the process dynamics.

Some processes change very slowly, having long residence times and stable feeds. Couple this with few operating variables, good process knowledge and a broad specification and you have the easiest of process control scenarios. Hourly measurements may well suffice.

For many, the challenge is tougher, with tight specifications – because that’s how you access premium markets – and a matrix of interconnected variables affecting product quality. Residence times are short and/or you have a variable feed from an upstream process. Now you need to measure much more frequently. In fact you’d like to know what’s going on all the time, exactly as it happens.

Real-time measurement beckons.

Switching on the light

Replacing periodic measurement with real-time analysis is like shining a light on every detail of your process. Think of driving in the pitch dark, only able to switch on your lights periodically, and then appreciate driving in daylight, constantly seeing the road and the results of your steering!

Real-time measurement allows you to see immediately the impact of a control action, making it so much easier to identify effective operational levers and how to change them to greatest effect. Instead of swinging the plant blindly from one overshoot to another, the operator can now navigate rapidly and smoothly to a new set point.

This is how real-time measurement improves process knowledge, and may even highlight a novel, more productive operating strategy.

Next time

Next time we’ll begin to look at the many financial benefits that flow from this transformation. Meanwhile we’d love to hear from anyone with new operating strategies illuminated by real-time measurement.