Mack Powers | May 21, 2021
Interview Transcript:
Mack Powers (00:08):
Hey, welcome today. I’m Mack Powers. I’m with Tom Whiteley. Today we’re going to be talking about CIP systems. When you’re designing and implementing an effective CIP system, there’re a number of critical things that you have to think about, especially those that are manufacturers in the regulated industries, such as the pharmaceutical, biotechnology, and the food and beverage industries. So Tom, as a process engineer, you’ve been asked a number of times to design and implement CIP systems. And there’s four Ts that you think about, right? When someone says help us get this thing designed, these four Ts would be time, temperature, turbulence, and turbidity. Can you explain to us today, what those mean and why they’re the critical parts of a CIP system?
Tom Whiteley (00:55):
The four Ts we’re talking about today really kind of tie into your wash cycle of your CIP cycle. The first one being time. Time really goes into how long you’re contacting the specific surfaces. It’s time at each of your steps or toggles, depending on how you look at it. And it’s driven really by your bio burden reduction program and how hot you’re running. So your temperature really ties very closely into your time. The higher temperature you can go safely from a EHS standpoint and from your pumps and hydraulics and your elastomer standpoint, the shorter your time can typically be. You do have have minimum times that you have got to meet such as your riboflavin contact time, just pass through time for your pipes to make sure that everything actually got heated up and flushed out, turned over that kind of thing.
Tom Whiteley (01:57):
And they also ties into your concentrations. Your turbidity or conductivity is how it’s typically measured these days. But that measurement also goes back to that bioburden reduction number. Within reason, your conductivity also ties into that calculation a little bit. You can reduce your time by upping your concentration. You can also dramatically increase it if… Some elastomer, some pieces of equipment just won’t tolerate a very high caustic concentration or won’t tolerate caustic at all and you have to go to an alternative chemical that can really drive up your time. Which obviously, you got to consider when you look at your total cycle times for your process versus CIP and your scheduling and everything else. So they all kind of tie together.
Tom Whiteley (02:56):
The last one is your turbulence, which is your flow rate. That ties in a little bit for like your line circuits to your time in that it goes back to your turnover. You do have a minimum flow rate, which is really driven by what it’s going to take to flood your piping, your Reynolds number calculations, those sorts of things. How well your piping is sloped and do you have pockets that are going to form if you don’t flood it at a higher rate? Then your flow rate ties into your spray coverage for your vessels. So it’s critical for both your vessels and your lines.
Mack Powers (03:38):
Makes sense. So those four pieces are then very critical. What happens if you get any one of them wrong? If you spend too much time or too little time, or you get the turbulence wrong, what could be the outcome?
Tom Whiteley (03:53):
So, like I said, they’re all kind of interwoven. If you pull one leg out, let’s say you don’t meet your spray coverage flow rates. You’re not contacting everything in your tank at that point. Now you have zones that aren’t being covered. If you’re not reaching your linear flow rates required in your pipes, then you’re not going to have good contact necessarily. You may leave air bubbles at your Ts. You may not break down the surface if you’re truly slow and you end up with linear flow, you’re really not going to scour the surfaces of your pipes. You’re not going to get a whole lot of cleaning action there. If your temperature’s below a certain threshold, you’re not going to have any… There’s certain things that’ll survive nearly indefinitely at certain temperatures. You won’t eliminate those bio burdens.
Tom Whiteley (04:42):
Too high of temperature and you start looking at things like cavitation in your pumps. Obviously, if you go real high, you can boil your CIP solution, which now we’re talking steaming instead of cleaning. But before you do that, typically you have issues with like pump seals, your valve seals, your elastomer in your system in general will generally have issues. And your pumps will typically cavitate. You won’t have the NPSH required for the pumps. So your temperature there. So, yeah, I think that that pretty much covers them all. Then you still have to have your contact times to just have the kill time.
Mack Powers (05:25):
Sure. Yeah. It kind of sounds easy when we just break it down to the four Ts, but the reality is getting them all to work together, synchronously to create the desired effect, it takes some experience and some knowledge of the subject. Certainly that’s something that a process engineer such as yourself is adept at. So thanks for helping us understand that today. I appreciate that explanation and it’s very helpful.
Tom Whiteley (05:53):
Yeah. It’s been good talking to you today, Mack.
Mack Powers (05:55):
Thank you, Tom.