Stop looking at pressure drop like this

Рет қаралды 2,852

Күн бұрын

I've monitored pressure drops on process plants before, and I admit I was guilty of the same thing I discuss here. Watch the video and then go sort out your process monitoring tools!
00:00 Intro
00:45 Pressure drop & system curves
02:20 Monitoring pressure drops on processes
03:27 An example of crappy monitoring
05:47 Limitations of square relationships
07:02 Conclusion
Process with Pat is the place to come for perspective and to ask stupid questions. I want you to leave more knowledgeable, confident, motivated, and most importantly, curious. I also want to invigorate a field that seems tired and uninspiring, at least if you get your perspective from internet forums. These are not lectures. This is a place for you to leave thinking “Oh! That’s why...”
This channel is not only for chemical engineers - anyone who works with processes should be able to find something of value here.
#ProcessEngineering
#ChemicalEngineering
#ProcesswithPat

Пікірлер: 16

@SoulofaPond 3 жыл бұрын

The fundamentals of all reverse osmosis operations put down to the T. You have quantity, you mentioned quality but also don't forget efficiency. Energy vectors, tds, anything that you are aiming for matters on the trinity. Thank you again

@ProcesswithPat 3 жыл бұрын

Brilliant addition! Maybe we should have you on some time?

@SoulofaPond 3 жыл бұрын

@@ProcesswithPat happily at your disposal grand mind

@FirstnameLastname-fn6ik 2 жыл бұрын

I hope this channel continues for a long time, every video is a knowledge gem for me!

@ProcesswithPat 2 жыл бұрын

Thanks for that! That’s the idea, I don’t wanna make videos that feel too much like lectures/something you can find elsewhere. There has to be some insight air application. Really appreciate it.

@NikolayBychkovRus 8 ай бұрын

@@ProcesswithPatI support the comment waiting for new videos:)

@ronnysharma6767 2 жыл бұрын

This is such a good point. Another important thing to point out is that as downstream pressure decreases, you start to generate more flow. I've seen situations where pressure control valves downstream of fixed speed pumps have been left in manual, and the down stream pressures started to decrease over time due to process related reasons. This ultimately caused flow to increase, and almost caused a safety system in the plant I was working at to activate. So this concept is super important to understand!

@alecslungaard4749 Жыл бұрын

Fantastic video. Thank you for adding visuals to accompany your insightful description of pressure drop. Keep up the great work!

@Jh-uy6qj Жыл бұрын

Which equation are you using to derive the square law for DP and Flow? Bernoulli requires a change in area to get that result but that wasn’t explicitly stated, is it Darcy-Weisbach?

@ProcesswithPat Жыл бұрын

I didn't strictly "derive" it. It is a knock-on effect from bernoully, where dP is proportional to velocity squares, but as I say, some equipment is shaped such that the exponent isn't necessarily a 2... It could be 1, 1.5, anything. It's just a rough application when I don't have data. But if you have actual data for flow vs dP, you should fit it.

@camibabyy 2 жыл бұрын

Is the square relation you showed for both liquid and gas? If it's gas don't you need to consider temperature? Or are you assuming isothermal? -- 3rd yr ChemE student

@ProcesswithPat 2 жыл бұрын

Generally yes, it’s for both liquids and gases, and absolutely temperature will play a role because pressure drop is related to density. Just keep in mind that it isn’t always a square relationship in all instances - that’s why we develop complicated equations and charts for pressure drops of things like heat exchangers. Nevertheless, scaling the pressure drop using a square relationship is better than using a fixed high alarm for all flow rates.

@carultch Жыл бұрын

Pressure drop is extremely non-linear, and there isn't a closed-form equation that describes it. For laminar flow of Newtonian fluids, it is a linear relationship between flow rate and pressure drop, that is a 1-to-1 analogy to Ohm's law in electrical circuits. For extreme turbulent flow, in the limit of high Reynolds' numbers, it asymptotically approaches a parabolic relationship, where pressure drop is approximately proportional to the square of flow rate. For transitional flow and moderate turbulent flow, there is no closed-form equation derived directly from theory, and the process to calculate this relationship is very round-about and indirect. There are empirical equations and charts based on generalizing flow in terms of Reynolds' number, and forming a curve-fit to the experimental results. This is what is used for predicting pressure drop from flow, or vice-versa. Most flows of water and air are turbulent. Laminar flow usually happens for more viscous fluids like oils.

@rasmussverdrup7479 3 жыл бұрын

Are you using bitcoin as an example of the intrinsic value of an object? Bold choice & Great video!

@ProcesswithPat 3 жыл бұрын

Don’t pretend you wouldn’t buy it if I offered it to you at that price! But yes, I thought It’s be hilarious to see how well (or poorly) this video ages.

@rasmussverdrup7479 3 жыл бұрын

@@ProcesswithPat To be honest I often go to friction or pressure drops to explain concepts like inflation, value and other economics stuff. But I mostly talk to my kids, so I could basically say anything.