Extraction Unit Sulfolane Solvent Regeneration
Aromatics extraction units employ a solvent to separate Aromatic compounds from other hydrocarbons. Sulfolane is one common compound used in the closed solvent loop process. Over time the solvent fouls, harming operation. Online solvent regeneration is performed to mitigate the deleterious effects of degradation.
(Article published as "Avoid Sulfolane Regeneration Problems," Donald F. Schneider, Chemical Engineering Progress, July, 2004.)
Caution is Not Safety
Preventing dangerous actions is equated with being safe. However, taking proper action is a very important aspect of safety. Overly cautious measures can impose, and possibly raise risks with many operations performed in processing facilities. In this case study, the "pros and cons" for the catalyst change of a C4 selective hydrotreater were evaluated.
(Article published as "Improve Catalyst Removal Methods," D.F. Schneider, Hydrocarbon Processing, October, 2000.)
Select the Right Hydrocarbon Molecular Weight Correlation
This paper examines molecular weight distribution predictions of ten different correlations for two different crude oils. The effects of these results are illustrated by examining simulation data for a typical crude and vacuum distillation unit for one of the crudes under study using molecular weight correlations which span the continuum of the predictions.
(Article published as "Select the Right Hydrocarbon Molecular Weight Correlation," D.F. Schneider, Chemical Engineering Progress, December, 1998.)
How to Calculate Purge Gas Volumes
Preparation for startup or shutdown involves purging contaminants from the process unit. Another important aspect of purging is the thorough removal of contaminants or hydrocarbons from equipment taken out of service for maintenance. Several presented methods quickly estimate the sweep gas quantity and cycles that perform an efficient purge.
(Article published as “How to Calculate Purge Gas
Volumes,” D.F. Schneider, Hydrocarbon Processing, November, 1993.)
Debottlenecking Economics - Maximizing Profitability with Minimum Capital
Increasing production to accommodate demand can be accomplished by
building new units or by debottlenecking existing capacity. This paper reviews
debottlenecking opportunities and strategies. Emphasis is placed on finding the lowest capital solution which provides the highest payback.
(Article published as "Debottlenecking options and optimisation," Donald F. Schneider, PTQ, Autumn, 1997.)
Plant Power Failures: Case Study of Indirect Effects on a Worldscale Olefins Plant
Operational upsets small and large often ripple through a hydrocarbon manufacturing facility. From a feed rate change to a thunderstorm these variations can have indirect impacts that may amplify the original disturbance. This discussion reviews a plant power failure upset and its resulting indirect effects.
(Article published as "Plant power failure and its indirect effects: a case study," Donald F. Schneider, PTQ, Winter, 1998/99.)
Plant Reliability - The Usual Suspects
Plant reliability is a quest for profitability. Reliable plants are also safer since higher risk maintenance activities are less frequent. We focus on repair frequency and repair cost. We squeeze these numbers towards the industry benchmarks. At times, perhaps for several months or a year, these numbers actually reach our goals and we are pleased. But invariably costs rise and failure rates increase. We wind up back at the start asking ourselves why.
(Article published as "Improving Plant Reliability: Look Beyond Usual Suspects," Donald Schneider, Chemical Engineering, October, 2003.)
Practical Process Hydraulic Considerations
A fluid moving through pipe or equipment is a well understood phenomena. There are fluid flow areas that would benefit from improved understanding. Two-phase flow, flow through packed beds, and flow associated with phase changes are examples. But for the most part existing analytical methods predict behavior reasonably well. However, having an understanding of what the fluid will do does not explain the affect it will have.
(Article published as "Practical process hydraulics considerations," D.F. Schneider and M.C. Hoover, Hydrocarbon Processing, August, 1999.)
Software Construction: Building a Process Model
Often one of the first steps taken in unit troubleshooting, optimization or debottlenecking, a complex system is the development of a computer model of the process. Increasingly, process safety management, operator training, engineering training, and environmental regulatory requirements are also aided by computer simulation. These electronic models provide powerful tools for equipment and system analysis.
(Article published as "Build a Better Process Model," Donald F. Schneider, Chemical Engineering Progress, April, 1998.)
Column Heat Input Limit Reveals Design & Operating Issues
As refiners work to increase unit production or accommodate feed composition changes with minimal capital investment, existing equipment design and operating conditions should be evaluated for opportunities. In many cases throughput limitations can be resolved through review and modification of existing equipment design.
(Article published as "Analysis of alky unit DIB exposes design, operating considerations" Donald F. Schneider, Joseph Musumeci, and Rick Chavez, Oil&Gas Journal, Sept. 30, 1996.)
Deep Cut Vacuum Tower Incentives for Various Crudes
Vacuum towers are one of the simpler refinery units since they are not a conversion unit like a hydrocracker or FCCU. However, vacuum units are very important because along with crude units they process all of a refinery's incoming crude. Crude and vacuum unit performance affects all downstream operations.
(Article published as "Deep cut vacuum tower processing provides major incentives" D.F. Schneider, J. Musumeci, Hydrocarbon Processing, November, 1997.)
Development of Microprocessor Control for a V-6 Engine Fueled by Prevaporized Methanol
A microprocessor based control system was developed to provide optimum operation of an engine fueled by prevaporized methanol. The results of this work show that strict control of engine performance was achieved using this throttle body fuel injection system.
A Thesis by Donald F. Schneider, Texas A&M University, August, 1985.
Heat Integration Complicates Heat Pump Troubleshooting
A naphtha fractionator unit had operated well for years but began to experience inexplicable warm weather trips of the heat pump compressor. During the summer the compressor would shut down on high discharge temperature for no apparent reason. Feed rates were high but not beyond design. The initial thought was that the compressor driver was inadequate. The Compressor driver was due for overhaul - it would be an opportune time to replace it with a high horsepower machine. Focusing on the compressor would be easy, and it might even be correct. However, you could also buy a large horsepower driver, put it in, and have the same problem. That would be an uncomfortable look-back meeting.
(Article published as "Heat integration complicates heat pump troubleshooting" D.F. Schneider, Hydrocarbon Processing, May, 2002.