100 Most asked questions by Chemical Engineers

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Sunday, September 23, 2018

Norm Lieberman Receives Lifetime Achievement Award from Hydrocarbon Processing


Norman Lieberman accepts 'Lifetime Achievement' Award at the 2018 HP Awards

August 30, 2018, HOUSTON-Nearly 150 of the midstream and downstream oil and gas industry's brightest minds gathered Thursday to find out, and celebrate, the winners of the 2018 HP Awards. The awards ceremony seeks to recognize and honor the midstream and downstream processing industry's top innovations and innovators.
Honorees took home awards in 12 categories-10 encompassing the latest technological advances in the hydrocarbon processing industry and two people awards - fr om the gala event in Houston, Texas. These innovations are enabling refinery, petrochemical and gas processing/LNG operators to optimize their operations.
In this year's 'Lifetime Achievement' category, Norman Lieberman was awarded for his lifetime work in the downstream processing industry. Mr. Lieberman began his career in 1965 with Amoco Oil, where he designed the first complex fractionator using a computer simulation. He has authored more than 100 articles, as well as 11 technical engineering books that are focused on solving processing problems. His continuing education courses on troubleshooting process operations have been attended by more than 18,000 engineers and technicians since 1983. Mr. Lieberman specializes in the retrofit design of crude units, FCU fractionators, delayed cokers, sulfuric acid and alkylation plants, and sulfur recovery units.
The 2018 HP Awards were generously sponsored by: AspenTech, Eni, Fluor and KBR.

Hydrocarbon Processing, the leading oil and gas trade journal for the hydrocarbon processing industry, has a worldwide circulation of more than 30,000 subscribers. Gulf Energy Information has published Hydrocarbon Processing for more than 96 years. Additional information on the HP Awards program can be found at www.HydrocarbonProcessing.com/Awards.                                                                                              ·

Press Contact:
Melissa Smith
Events Director, Downstream Gulf Energy Information

Sunday, March 26, 2017

Oil & Gas Journal: “Beyond Back-to-Basics: Process Principles & Concepts.”

Wednesday, October 28, 2015


Amine Circulation

Mr. Lieberman, which is a better amine – MEA, DEA, or MDEA – for use in a refinery?


MEA, without good reclaimer operation, in a plant with an FCU, is going to promote H2 assisted stress corrosion cracking. MDEA is used in concentrations of 45%, and hence tends to foam. In practice, I have found using 30 – 35 wt.% DEA is optimum – but occasional reclaiming to reduce heat stable salt accumulation is still required. If you have a sulfur plant tail gas scrubber, then a selective solvent, that rejects CO2 absorption, such as MDEA may be necessary.

Monday, October 26, 2015


Sulfuric Acid Alky

Our alky unit refrigeration compressor is limited by low suction pressure. The suction pressure gets down to one psig or less, but contactor temperature is 60°F or more. So, we slow down the compressor (turbine driver), to bring up the suction pressure, but then the contactors get hotter still. Any suggestions would be appreciated.


May I suggest you reduce your depropanizer bottoms temperature by 5°F. This will allow propane to build in your refrigerant recyle and raise compressor suction pressure, but without raising contactor temperature. You need to make moves on the depropanizer bottoms temperature slowly, as it will take several hours for the refrigerant recycle propane content to respond. Note, that if your compressor discharge pressure is at max, this will not work.



On our FCU wet gas compressor, we have an orifice plate that operates from 0” to 100” of water DP. The flow is typically high. The meter reads full scale – at an orifice plate DP of 95” H2O, or 3½ psi pressure drop. As the compressor suction pressure is only 3 psig, it seems to me that we are wasting a lot of compressor capacity on that orifice plate. What do you suggest? Also, high compressor suction pressure backs air out of the regenerator.


Eliminate the orifice plate. Use the vapor outlet nozzles of the upstream K.O. drum, as a restriction orifice. Measure the DP between the drum and the compressor suction. You can back-calculate the “orifice” coefficient based on the unit material balance. I’ll show you how to do this, if you send me the operating data. Looks like you can increase compressor capacity by about 10%, with zero investment cost.

Wednesday, October 7, 2015


Delayed Coker

My coker fractionation tower top pressure surges higher by 5 psi for a few hours. Tower top temperature jumps by 20°F - 40°F. The level in light gas oil pan drops. This occurs every few days. What’s happening?


You’re salting-up the top few trays. The top reflux can’t cool off the upper trays. They get hot, and sublime off the salts. A simple way to prevent the problem, is to periodically heat up the top of the tower, maybe for 30 minutes by 30°F, every few days. I’m not too sure about time and temperature factors. Periodic water washing is also possible, but a lot more complicated.


Vacuum Tower

In a vacuum tower, what parts of tower internals need to be designed for a large up-lift force, to prevent damage?


Only the over-flash chimney tray, if the chimneys are designed for a 0.5 – 1.0 mm Hg DP.



When I increased crude tower bottom stripping steam from 1,200 to 2,500 lbs/hr, I increased diesel yield by 1,000 BSD at the expense of LVGO. Vacuum, in the vacuum tower, improved from 25 to 18 mm Hg. Yet, vacuum resid yield failed to improve. Why not?

Reduction in vaporization of diesel in flash zone of vacuum tower, off-set reduction in pressure:

·       % vaporized prop. to  (V/1 • 1/P)