Friedman, Y. Z.

Petrocontrol, New York, New York

Y. Zak Friedman is a Principal Consultant with Petrocontrol. He has practiced APC for most of his career, specializing in using first-principles models for inferential process control and has developed inferential models to fit many hydrocarbon processes. Dr. Friedman’s experience spans more than 50 yr, working with Exxon Research and Engineering, KBC Advanced Technology and Petrocontrol. He holds a PhD degree from Purdue University.

Process Control, Instrumentation and Automation: Distillation column DCS control configuration

Friedman, Y. Z., Petrocontrol

Is there a consensus about a distillation column distributed control system (DCS) control strategy? Much has been written about this topic, covering configuration possibilities, constraints and interacting control considerations.

Advanced process control of debutanizers makes use of inferential predictions

Ferrari, L., Harrison, P., Total; Friedman, Y. Z., Petrocontrol

Following good experience with a generalized cut-point calculation (GCC) inferential package, which models main fractionators with side streams, French energy major Total decided to experiment with a generalized distillation shortcut (GDS) inferential package, which models simpler, two-product distillation columns.

HP Control: How difficult is it to control absorber columns?

Friedman, Y. Z., Petrocontrol

The absorber-stripper configuration is common for gas plants. If we are to apply advanced process control (APC) systems on a gas plant, it better to address the control problem—maximizing recover..

HP Control: Inferential control model input selection

Friedman, Y. Z., Petrocontrol

It is not a secret that I prefer to base inferential models on engineering principles, rather than on regression. Having said that, the use of regression is widespread, and being a consultant in the f..

HP Control: APC application ownership

Friedman, Y. Z., Petrocontrol

Advancec process control (APC) requires skilled control engineers, and where such engineers are not available, even well-implemented APC applications quickly become ineffective. That much is known and..

HP Control: Total- or partial-draw configuration

Friedman, Y. Z., Petrocontrol

Ever wonder why some main fractionators are designed with partial-draw trays, whereas others are total draws? A typical partial-draw with pumparound configuration is shown in Fig. 1. Liquid is taken f..

HP Control: Distillation column dual-temperature control—Part 2

Friedman, Y. Z., Petrocontrol

Part 1 of this editorial1 has considered a distillation dual temperature control structure and concluded that such strategy is problematic and not likely to work. If you accept that dual-temperature c..

HP Control: Distillation column dual-temperature control-Part 1

Friedman, Y. Z., Petrocontrol; Goble, W., exida LLC

This editorial takes issue with a claim by Mr. Greg Shinskey that distillation dual-composition control cannot be done effectively by a multivariable predictive controller (MPC), but can be done effec..

HP Control: Temperature points on main fractionators

Friedman, Y. Z., Petrocontrol

Main fractionators are distillation columns that handle wide boiling curve feeds, cutting it into several products. Almost every major refinery unit has such a column, all with similar design features..

HP Control: APC designs for minimum maintenance—Part 3

Friedman, Y. Z., Petrocontrol

This is the third in a series of three editorials about designing advanced process control (APC) applications for an environment of little to no maintenance. Having lamented for years about APC applic..