Many years ago now, I implemented a significant process control improvement around the top of a debutaniser column and this significantly improved overall control of the column.
The E101 debutaniser column is used to remove LPG and Fuel gas from a gasoline product. It is critical that the light …
Over the last couple of weeks I have been dusting off and attempting to update my CV and LinkedIn profile (for obvious reasons). One thing that is becoming obvious is that I am struggling to convey my multi-discipline background. I have experience and could equally work well as an operations …
I have a Honeywell TDC/TPS tag that needs to be deleted. The system will not let me delete it if the point is still active. I Inactive the tag from the point detail display, then go to the builder tools page and select delete system entity.
Unfortunately when I …
Since starting work after leaving university, I have found several terms thrown around when talking about the control system. In every factory I have worked in, they have had a DCS, though some parts of it were controlled by PLCs. In some documents or training courses, I have seen references …
Continuing after last week's discussion about process noise, I will now cover another tool used to help mitigate noise.
Deadbands are useful when the the result is a digital signal, it is either on or off. Most control loops are analogue and have a range of outputs, usually a control …
Previously I have talked about noise in the measurements that are used to control the process. These variations can cause the system to react unnecessarily and introduce disturbances to the process.
While we should always try to avoid noise by selecting suitable instruments and installing …
What is noise? Depends on what subject you are talking about. If you are talking about what your ears sense, then it is a bunch of pressure waves that move through the air. But in the case of this post, I am actually talking about noise in a process control …
Alarms are the control system's was of shouting at the operator. If saying "STOP WHAT YOU ARE DOING AND LOOK AT THIS". The problem is that it takes time for the operator to stop what they were doing, look at the alarm. Then look at what else is going on …
This post explains different types of alarm that can be used on a control system.
These are the simplest type of alarm. The control system measures something such as pressure, temperature, level or flow, and compares it with the alarm value. If the measured number is …
I do not think that we covered override control loops while at university, the first time I came across them was in the sugar factory. Yet they are used a lot and are incredibly useful. I don't understand why they aren't covered in introductory control classes.
Override control can come …
Most control loops try to keep whatever is measured at a value set by the operator (SetPoint, SP). Sometimes the operator lets something else decide the setpoint. This is called cascade.
In most cases this means two control loops work together. The output of the first decides the setpoint of …
In last week's edition of Simple Saturdays, I talked about control loops. This week I will talk about the PID loop. Unlike many explanations of the PID loop, I will keep it simple. I will avoid showing the equation that a controller uses. The truth is that as a control …
Today we had a perfect example of distributed control working.
The way our DCS is set up is with individual plants on their own local networks and these are connected to a central network that runs to the control room where the operators and the advanced control schemes that work …
I realise that I graduated university over 10 years ago now. Earlier today I wanted to check the exact date so I looked out a copy of my certificate. Sure enough, the 10 year anniversary was at some point last month. What was also stored with the certificate was my …
Yesterday I was able to attend a presentation on alarms and HMIs1by Bill Hollifield. Bill quiet literally wrote the books on alarms and HMIs.
The first part of the presentation was on alarm management, what problems different sites face and how to fix them. To be honest, there …
One of the discussions that happened after the previous Disastrous Dinners talk covered operator fatigue, particularly when performing monotonous activities that still require a great deal of focus.
The conversation started with a discussion about how much distraction you allow in a control room. Do you ban all Personal phones …
This month’s process safety beacon is on trusting instruments. Or to be more accurate, what can happen when you don’t believe an instrument and it turns out that the instrument was correct. It has prompted me to write about an incident I experienced last year. Luckily in our …
Yesterday we fixed a problem with one of our optimisers by, as you can probably tell from the title, turning (a bit of) it off and on again.
In this case it wasn't as simple as flicking the switch on the wall. It was one module on a remote computer …
So it turns out there is a bit more I want to say about the Merrimack Valley Gas Explosions.
In yesterday’s post, I was rather critical of the immediate recommendations that were produced by the investigators. They seemed to be very focused on the human error side of things …
In my final post on the Merrimack Valley Explosions1 , I want to cover the recommendations that were issued in the Safety Recommendation Report. The report makes five urgent recommendations, one to the state of Massachusetts and four to NiSource, Inc., the parent company of the operating company in charge …
In today's post about the Merrimack Valley Explosions, I want to discuss the mitigating factors and layers of protection, or rather apparent lack of then in this case. Again I will clearly state, I don't have all the facts and am not in anyway involved. I only have access to …
I mentioned in yesterday's post about a series of gas explosions that occured while I was visiting family in the USA last year. In this post I will cover how this event that 'looked like armageddon' according to a fire chief.
As with most utilities, the gas network consists of …
While I was in America last year, I saw news reports of an accident in Massachusetts where a local residential gas network was overpressured. This lead to lots of explosions and fires over three different towns. The local emergency services received over a hundred 911 emergency calls within a short …
Today I implemented a fix that will hopefully avoid a repeat of an incident that happend last week. It is the sort of problem that I enjoy to work on. Why isn't this doing what we would expect? And more importantly how do I get it to do what I …
We are in the process of designing and building a new control room at the refinery. This will replace the building built in the 70s and the control system that has an user interface that doesn't look particularly different from the photographs of when it opened.
This is obviously a …
I have read lots of things in the last week talking about how we should write simpler and not to trust things that are written in a confusing way or using long words.
I know that I can be bad at this and so I would like to try and …
As a control engineer, I work on automating stuff. Automating things is something that I have enjoyed doing for years whether in a factory, a theatre or just on a computer.
And yet I still find it magical whenever I set up something new. If that feeling goes, I know …
I frequently see people make a comment regarding procedures along the lines of "monkey see, monkey do", "they take the thought out of the job" or "they treat us like idiots".
I want to take this opportunity to say that is not how I see or use procedures. If you …
I have previously written about alarms and following on from yesterday's post I want to write about stale alarms.
These are alarms that initially come in, but for some reason the operator cannot remove them. They are usually classed as stale if they have been on the alarm page continuously …
I have previously written about nuisance alarms particularly during shutdowns, but today I want to cover the fundamental questions of what an alarm is and what it is not.
The definition of an alarm is:
Alarm: An audible and/or visible means of indicating to the operator an equipment malfunction …
Today we had a school pupil shadowing our team, trying to work out what a carrier in chemical engineering would be like. Earlier in the week she spent time with developement and optimisation engineers but today it was the turn of the automation team to explain what control engineers do …
Over the last few weeks, I have been commissioning a couple of new Advance Process Control (APC) schemes within the refinery and it occurs to me that this is very similar to looking after a toddler in the house.
When looking after the little one, you can …
Earlier today I commissioned a project I have been working on for the last year, ESD Dynamic Alarm Suppression.
When the Emergency Shutdown (ESD) System is activated, shutdown valves will close and pumps will stop. This normally causes a significant flood of extra alarms as the normal control system warns …
I have just attended a Lunch and Learn session delivered by JWF Process Solutions Ltd and hosted by the Institute of Measurement and Control East of Scotland Section.
This presentation focused on clamp on ultrasonic flow meters and their recent developments.
I have had a small amount of experience with …
This Presentation was delivered on behalf of the IChemE Scottish Members Group on Thursday 2nd June 2016 at Ineos Grangemouth. I have attached a copy of the slides however they are not very descriptive on their own. This post is a summary of what …
I had an odd experience last night when I received an email from IChemE inviting me to a presentation that is to be delivered by myself.
No getting out of it now then. My intent is to provide a general introduction to instrumentation and cover things that I have learnt …
So I have just completed the course on advanced process control. It was interesting on Sunday night when I met the other course attendees.
There were eight attendees in total, I was the only Brit, all others were from continental Europe (Dutch, Belgian and German). There was a definite feeling …
So after yesterdays post concerning being slightly worried about switching back into control engineer mode, this morning I am even more worried.
I arrived at the hotel just in time for dinner and met five of the other attendees (there are eight of us in total on the course). All …
The Cat Reformer is mostly back together. Hopefully later today, hydrogen can be introduced. If everything goes well, feed should be put back in on Tuesday.
For myself though the TAR is over. I am currently on a train on my way to Cardiff for a training course next week …
