Washington University Magazine, Winter 2007

https://digitalcommons.wustl.edu/ad_wumag/1182/thumbnail.jp

Inferential active disturbance rejection control of distillation columns

PhD ThesisThe distillation column is an important processing unit in the chemical and oil refining industry. Distillation is the most widely employed separation method in the world’s oil plants, chemical and petrochemical industrial facilities. The main drawback of the technique is high energy consumption, which leads to high production costs. Therefore, distillation columns are required to be controlled close to the desired steady state conditions because of economic incentives. Most industrial distillation columns are currently controlled by conventional multi-loop controllers such as proportional-integral-derivative (PID) controllers, which have several shortcomings such as difficulty coping with sudden set-point jumps, complications due to the integral term (I), and performance degradation due to the effect of noise on the derivative term (D). The control of ill-conditioned and strongly non-linear plants such as high purity distillation needs advanced control schemes for high control performance. This thesis investigates the use of active disturbance rejection control (ADRC) for product composition control in distillation columns. To the author’s knowledge, there are few reported applications of ADRC in the chemical industry. Most ADRC applications are in electrical, robotics and others. Therefore, this research will be the first to apply the ADRC scheme in a common chemical processing unit, and can be considered as a first contribution of this research. Initially, both PI and ADRC schemes are developed and implemented on the Wood–Berry distillation column transfer function model, on a simulated binary distillation column based on a detailed mechanistic model, and on a simulated heat integrated distillation column (HIDiC) based on a detailed mechanistic model. Process reaction curve method and system identification tools are used to obtain the 2×2 multi-input multi-output (MIMO) transfer function of both binary and HIDiC for the purpose of PI tuning where the biggest log-modulus tuning (BLT) method is used. Then, the control performance of ADRC is compared to that of the traditional PI control in terms of set-point tracking and disturbance rejection. The simulation result clearly indicates that the ADRC gives better control performance than PI control in all three case studies. The long time delay associated with product composition analysers in distillation columns such as gas chromatography deteriorates the overall control performance of the ADRC scheme. v To overcome this issue an inferential ADRC scheme is proposed and can be considered as a second contribution of this research. The tray temperatures of distillation columns are used to estimate both the top and bottom product compositions that are difficult to measure on-line without a time delay. Due to the strong correlation that exists in the tray temperature data, principal component regression (PCR) and partial least square (PLS) are used to build the soft sensors, which are then integrated into the ADRC. In order to overcome control offsets caused by the discrepancy between soft sensor estimation and actual compositions measurement, an intermittent mean updating technique is used to correct both the PCR and PLS model predictions. Furthermore, no significant differences were observed from the simulation results in the prediction errors reported by both PCR and PLS. The proposed inferential ADRC scheme shows effective and promising results in dealing with non-linear systems with a large measurement delay, where the ADRC has the ability to accommodate both internal uncertainties and external disturbances by treating the impact from both factors as total disturbances that will then be estimated using the extended state observer (ESO) and cancelled out by the control law. The inferential ADRC control scheme provides tighter product composition control that will lead to reduced energy consumption and hence increase the distillation profitability. A binary distillation column for separating a methanol–water mixture and an HIDiC for separating a benzene–toluene mixture are used to verify the developed inferential ADRC control scheme.Petroleum Development of Oman (PDO) for their generous support and scholarshi

Outlook Magazine, Spring 1997

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Enabling hybrid process metrology in roll-to-roll nanomanufacturing: design of a tip-based tool for topographic sampling on flexible substrates

This work seeks to demonstrate the efficacy of a novel approach for topography measurement of nano-scale structures fabricated on a flexible substrate in a roll-to-roll (R2R) fashion. R2R manufactured products can be extremely cost competitive compared to more traditional, silicon wafer or glass panel based nanofabrication solutions, in addition to the unique and often desirable mechanical properties inherent to flexible substrates. As such, flexible nanomanufacturing is an area of immense research interest. However, despite the significant potential of these products for a variety of applications, developing manufacturing systems from lab-scale prototypes to pilot- or high volume manufacturing (HVM) has often proven both difficult and infeasibly expensive as research investment and achievable process yield limit advancement. One of the most significant capability gaps in current art, and roadblocks on the path towards adoption of R2R nanomanufacturing, is the lack of high-throughput, nanometer-scale metrology for process development, real-time control, and yield enhancement. This dissertation presents the design of a tip-based measurement tool implementing atomic force microscope (AFM) probes manufactured with a micro-electro-mechanical system (MEMS) approach to the challenge of sub-micron topography measurement which is also compatible with R2R manufacturing on flexible substrates. A proof-of-concept prototype tool with subsystems to regulate a flexible web, isolate and position the atomic force microscope probe, and measure features on the substrate, all coordinated by a real-time embedded control system, was designed and fabricated. The positioning subsystem was evaluated dynamically to ensure initial design requirements were met, and stationery, step-and-scan results were presented. However, to wholly meet this extent need for in-line R2R metrology, a system capable of atomic force microscope scanning despite a continuous, non-zero substrate velocity is required - any regular stoppage of the web in a R2R process all but dooms economically viable production throughput. Refinement and redesign of the proof-of-concept tool was driven by new system requirements to meet this goal, in addition to lessons learned from the initial prototype. Improvements focused on upgrading the web handling spindle design and mechatronics, tool power electronics, moving structures, and control algorithms used for high-speed synchronous positioning of the atomic force microscope and web. The culmination of this work will serve to introduce a new measurement framework which may be used to accelerate and enable future research in R2R manufacturing of nanofeatured products.Mechanical Engineerin

Corn Processing Co-Products Manual: A Review of Current Research on Distillers Grains and Corn Gluten

Table of Contents: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 General Overview of Feeding Corn Milling Co-Products to Beef Cattle . . . . . . . . 3 Feeding Distillers Grains to Dairy Cattle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 DDGS in Poultry Diets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Corn Distillers Dried Grains with Solubles for Swine. . . . . . . . . . . . . . . . . . . . . . . 22 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Order Form for 2005 AAFCO Official Publication. . . . . . . . . . . . . . . . . . . . . . . . . 2

ESSE 2017. Proceedings of the International Conference on Environmental Science and Sustainable Energy

Environmental science is an interdisciplinary academic field that integrates physical-, biological-, and information sciences to study and solve environmental problems. ESSE - The International Conference on Environmental Science and Sustainable Energy provides a platform for experts, professionals, and researchers to share updated information and stimulate the communication with each other. In 2017 it was held in Suzhou, China June 23-25, 2017

Dynamic modeling and control strategies of organic Rankine cycle systems: Methods and challenges

Organic Rankine cycle systems are suitable technologies for utilization of low/medium-temperature heat sources, especially for small-scale systems. Waste heat from engines in the transportation sector, solar energy, and intermittent industrial waste heat are by nature transient heat sources, making it a challenging task to design and operate the organic Rankine cycle system safely and efficiently for these heat sources. Therefore, it is of crucial importance to investigate the dynamic behavior of the organic Rankine cycle system and develop suitable control strategies. This paper provides a comprehensive review of the previous studies in the area of dynamic modeling and control of the organic Rankine cycle system. The most common dynamic modeling approaches, typical issues during dynamic simulations, and different control strategies are discussed in detail. The most suitable dynamic modeling approaches of each component, solutions to common problems, and optimal control approaches are identified. Directions for future research are provided. The review indicates that the dynamics of the organic Rankine cycle system is mainly governed by the heat exchangers. Depending on the level of accuracy and computational effort, a moving boundary approach, a finite volume method or a two-volume simplification can be used for the modeling of the heat exchangers. From the control perspective, the model predictive controllers, especially improved model predictive controllers (e.g. the multiple model predictive control, switching model predictive control, and non-linear model predictive control approach), provide excellent control performance compared to conventional control strategies (e.g. proportional–integral controller, proportional–derivative controller, and proportional–integral–derivative controllers). We recommend that future research focuses on the integrated design and optimization, especially considering the design of the heat exchangers, the dynamic response of the system and its controllability

1996 Beef Cattle Report

Contents: Cow-Calf: Range or Meadow Regrowth Grazing and Weaning Effects on Two Year-Old Cows • Grazing: An Alternative to Haying Subirrigated Meadows in the Nebraska Sandhills • Multi-elemental Analysis of Sandhills Meadow Hay • Use of a Metabolizable Protein System to Predict Deficienciesin Diets of Cattle Grazing Sandhills Native Range and Subirrigated Meadow • Rumen Degradable Protein Requirements of Gestating Beef Cows Grazing Dormant Native Sandhills Range • Multi-elemental Analysis of Liver Biopsies and Serum to Determine Trace Element Status of Cows • Multi-elemental Analysis of Bovine Liver Biopsy and Whole Liver • The Incidence of Precocious Puberty in Developing Beef Heifers • Winter Temperatures May Affect Calf Birth Weights Growing: Evaluation of Animal Byproducts for Escape Protein Supplementation • Treated Meat and Bone Meal and Rumen Protected Methionine and Tryptophan for Growing Calves • Dried Poultry Waste as a Nonprotein Nitrogen Source for Ruminants • Manipulation of Microbial Protein Degradation in the Rumen: Development of the “Smugglin Concept” to Control Protein Digestion • Characterization of Ammonia Utilization by Prevotella ruminicola B14 • Cellulose Adherence Factors in Ruminococcus albus • Effect of Sorghum and Cornstalk Grazing on Crop Production • Winter Calf Grazing and Field Windbreaks • Use of Cell Culture to Study Muscle Growth in Beef Cattle Finishing: Grazing Systems Utilizing Forage Combinations • Beef Production Systems from Weaning to Slaughter in Western Nebraska • Feeding Value of Light-Test Weight Corn for Growing and Finishing Steers • Roughage Source and Particle Size in Finishing Diets • Effect of Energy Source and Escape Protein on Receiving and Finishing Performance and Health of Calves • Evaluation of Levels of Wet Corn Gluten Feed and Addition of Tallow • Evaluation of Wet Distillers Byproducts Composite for Finishing Ruminants • Digestibility of Wet and Dry Distillers Grains from the Fermentation of Corn or Sorghum • Use of Direct Fed Microbials to Alleviate Subacute Acidosis • An Enzyme-Microbial Feed Product for Finishing Steers • Effects of Bovatec, Rumensin or GrainPro Fed to Yearling Summer Grazing Steers • Growth Implants for Steers • Implant and Slaughter Time for Finishing Cattle • Evaluation of Nitrogen, Phosphorus, and Organic Matter Balance in the Feedlot as Affected by Nutrition • Compositing - A Feedlot Waste Management Alternative Beef Products: Predicting Wholesale Value of Beef Carcasses • Connective Tissue/Acidic Phosphate Preblends in Low Fat, High Added-Water Frankfurters • Gelatinized High Added-Water Beef Connective Tissue Protein Gels as Potential Water Binders • Mechanically Recovered Neck Bone Lean Alters Textural and Sensory Properties of Ground Beef Pattie