scholarly journals AN ASSESSMENT OF THE MATERIALS OF CONSTRUCTION FOR THE TRANSFER LINES AND UNIT OPERATIONS EQUIPMENT ASSOCIATED WITH THE RECYCLE DIVERSION PROCESS

2021 ◽  
Author(s):  
BRUCE WIERSMA
Keyword(s):  
Transfer Lines ◽  
Unit Operations

Use of vent stack temperature as a feedforward variable for dissolver total titratable alkali (TTA) control

TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 261-269
Author(s):  
Wei Ren ◽  
Brennan Dubord ◽  
Jason Johnson ◽  
Bruce Allison
Keyword(s):  
Feedback Control ◽  
Current Practice ◽  
Feedforward Control ◽  
Control Variable ◽  
Indirect Measurement ◽  
Tight Control ◽  
Transfer Lines ◽  
Green Liquor ◽  
Process Dynamics ◽  
Downstream Processes

Tight control of raw green liquor total titratable alkali (TTA) may be considered an important first step towards improving the overall economic performance of the causticizing process. Dissolving tank control is made difficult by the fact that the unknown smelt flow is highly variable and subject to runoff. High TTA variability negatively impacts operational costs through increased scaling in the dissolver and transfer lines, increased deadload in the liquor cycle, under- and over-liming, increased energy consumption, and increased maintenance. Current practice is to use feedback control to regulate the TTA to a target value through manipulation of weak wash flow while simultaneously keeping dissolver density within acceptable limits. Unfortunately, the amount of variability reduction that can be achieved by feedback control alone is fundamentally limited by the process dynamics. One way to improve upon the situation would be to measure the smelt flow and use it as a feedforward control variable. Direct measurement of smelt flow is not yet possible. The use of an indirect measurement, the dissolver vent stack temperature, is investigated in this paper as a surrogate feedforward variable for dissolving tank TTA control. Mill trials indicate that significant variability reduction in the raw green liquor TTA is possible and that the control improvements carry through to the downstream processes.

Increasing revenue and reducing cost through the use of advanced process control technology in the sugar industry

2016 ◽  
pp. 620-624
Author(s):  
Scott Kahre
Keyword(s):  
Process Control ◽  
Sugar Industry ◽  
Operating Cost ◽  
Control Technology ◽  
Advanced Process Control ◽  
Output Controller ◽  
Complex Processes ◽  
Unit Operations ◽  
Sugar Unit ◽  
Optimum Cost

Advanced process control technology can provide sugar processors the ability to realize major revenue enhancements and/or operating cost reductions with low initial investment. One technology in particular, model predictive control (MPC), holds the potential to increase production, reduce energy costs, and reduce quality variability in a wide variety of major sugar unit operations. These include centrifugal stations, pulp dryers, extractors, diffusers, mills, evaporating crystallizers, juice purification, and more. Simple payback periods as low as two months are projected. As a PC-based add-on to existing distributed control systems (DCS) or programmable logic controller (PLC) systems, MPC acts as a multi-input, multi-output controller, utilizing predictive process response models and optimization functions to control complex processes to their optimum cost and quality constraints.

UNIT OPERATIONS SECTION QUARTERLY PROGRESS REPORT, JANUARY--MARCH 1968.

1969 ◽  
Author(s):  
M. E. Whatley ◽  
P. A. Haas ◽  
L. E. McNeese ◽  
A. D. Ryon ◽  
C. D. Watson
Keyword(s):  
Progress Report ◽  
Unit Operations

Bioseparations Science and Engineering

2015 ◽  
Author(s):  
Roger G. Harrison ◽  
Paul W. Todd ◽  
Scott R. Rudge ◽  
Demetri P. Petrides
Keyword(s):  
Process Design ◽  
Qualitative Description ◽  
Engineering Practice ◽  
Unit Operation ◽  
Science And Engineering ◽  
Scientific Application ◽  
General Application ◽  
Unit Operations ◽  
Analysis Computer ◽  
Consistent Method

Designed for undergraduates, graduate students, and industry practitioners, Bioseparations Science and Engineering fills a critical need in the field of bioseparations. Current, comprehensive, and concise, it covers bioseparations unit operations in unprecedented depth. In each of the chapters, the authors use a consistent method of explaining unit operations, starting with a qualitative description noting the significance and general application of the unit operation. They then illustrate the scientific application of the operation, develop the required mathematical theory, and finally, describe the applications of the theory in engineering practice, with an emphasis on design and scaleup. Unique to this text is a chapter dedicated to bioseparations process design and economics, in which a process simular, SuperPro Designer® is used to analyze and evaluate the production of three important biological products. New to this second edition are updated discussions of moment analysis, computer simulation, membrane chromatography, and evaporation, among others, as well as revised problem sets. Unique features include basic information about bioproducts and engineering analysis and a chapter with bioseparations laboratory exercises. Bioseparations Science and Engineering is ideal for students and professionals working in or studying bioseparations, and is the premier text in the field.

Protein Purification Techniques

2001 ◽  
Keyword(s):  
Cell Culture ◽  
Protein Purification ◽  
Mammalian Cell Culture ◽  
Scale Up ◽  
Analytical Techniques ◽  
Structure And Function ◽  
Unit Operations ◽  
Practical Guidelines ◽  
P Proteins ◽  
And Function

Proteins are an integral part of molecular and cellular structure and function and are probably the most purified type of biological molecule. In order to elucidate the structure and function of any protein it is first necessary to purify it. Protein purification techniques have evolved over the past ten years with improvements in equipment control, automation, and separation materials, and the introduction of new techniques such as affinity membranes and expanded beds. These developments have reduced the workload involved in protein purification, but there is still a need to consider how unit operations linked together to form a purification strategy, which can be scaled up if necessary. The two Practical Approach books on protein purification have therefore been thoroughly updated and rewritten where necessary. The core of both books is the provision of detailed practical guidelines aimed particularly at laboratory scale purification. Information on scale-up considerations is given where appropriate. The books are not comprehensive but do cover the major laboratory techniques and common sources of protein. Protein Purification Techniques focuses on unit operations and analytical techniques. It starts with an overview of purification strategy and then covers initial extraction and clarification techniques. The rest of the book concentrates on different purification methods with the emphasis being on chromatography. The final chapter considers general scale-up considerations. Protein Purification Applications describes purification strategies from common sources: mammalian cell culture, microbial cell culture, milk, animal tissue, and plant tissue. It also includes chapters on purification of inclusion bodies, fusion proteins, and purification for crystallography. A purification strategy that can produce a highly pure single protein from a crude mixture of proteins, carbohydrates, lipids, and cell debris to is a work of art to be admired. These books (available individually or as a set)are designed to give the laboratory worker the information needed to undertake the challenge of designing such a strategy.

scholarly journals A novel technique for residence time distribution (RTD) measurements in solids unit operations

2021 ◽  
Vol 32 (2) ◽  
pp. 611-618
Author(s):  
Atena Dehghani Kiadehi ◽  
Mikel Leturia ◽  
Franco Otaola ◽  
Aissa Ould-Dris ◽  
Khashayar Saleh
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Novel Technique ◽  
Unit Operations

scholarly journals Probing the Effect of Water Recycling on Flotation through Anion Spiking Using a Low-Grade Cu–Ni–PGM Ore: The Effect of NO3−, SO42− and S2O32−

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 340
Author(s):  
Mathew Dzingai ◽  
Malibongwe S. Manono ◽  
Kirsten C. Corin
Keyword(s):  
Water Chemistry ◽  
Froth Flotation ◽  
Water Source ◽  
Threshold Concentration ◽  
Process Water ◽  
Low Grade ◽  
Unit Operations ◽  
Flotation Performance ◽  
Anion Distribution ◽  
Nickel Grade

Water scarcity necessitates the recycling of process water within mineral processing practices. This may however come with its disadvantages for unit operations such as froth flotation as this process is water intensive and sensitive to water chemistry. It is therefore important to monitor the water chemistry of the recycle stream of process water and any other water source to flotation. Monitoring the concentrations of the anions in recycled process water is therefore important to consider as these are speculated to impact flotation performance. Batch flotation tests were conducted using synthetically prepared plant water (3 SPW) with a TDS of 3069 mg/L as the baseline experiment. 3 SPW contained 528 mg/LNO3− and 720 mg/L SO42−, other anions and cations, and no S2O32−. Upon spiking 3 SPW with selected anions, viz, NO3−, SO42− and S2O32−, it was noted that NO3− and SO42− exhibited threshold concentrations while S2O32− did not show a threshold concentration for both copper and nickel grade. Spiking 3 SPW with 352 mg/L more of NO3− to a total 880 mg/L NO3− concentration resulted in the highest copper and nickel grade compared to 3 SPW while increasing the S2O32− from 60 to 78 mg/L increased nickel and copper grade. 720 to 1200 mg/L SO42− and 528 to 880 mg/L NO3− were deemed the concentration boundaries within which lies the threshold concentration above which flotation performance declines with respect to metal grades, while for S2O32− the threshold concentration lies outside the range considered for this study. Anion distribution between the pulp and the froth did not seem to impact the recovery of copper or nickel. Notably, the correlation between the concentrate grades and anion distribution between the froth and the pulp seemed to be ion dependent.

scholarly journals An Integrated Approach for the Valorization of Cheese Whey

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 564
Author(s):  
Francisco J. Barba
Keyword(s):  
Cheese Whey ◽  
Integrated Approach ◽  
Complete Recovery ◽  
Microbial Load ◽  
Processing Technologies ◽  
Whole Process ◽  
Unit Operations ◽  
Safe Product ◽  
Development Goals ◽  
Cheese Production

Taking into account the large amount of whey that is produced during the cheese production process and the constant demand by society for more sustainable processes, in accordance with Sustainable Development Goals (SDGs) and the circular economy concept, it is necessary to adapt two-unit operations into a single process, allowing us to not only valorize a part of the whey but the whole process, which is known as bioprocess integration. In this sense, the adaptation of different processes, for example, physicochemical (micro, ultra and nanofiltration) and fermentation, that are commonly used to obtain proteins, lactose and other compounds with different activities (antioxidant, antifungal, etc.) could be integrated to achieve a complete recovery of the cheese whey. Likewise, keeping in mind that one of the main drawbacks of cheese whey is the great microbial load, some innovative processing technologies, such as high hydrostatic pressures, electrotechnologies and ultrasound, can allow both the development of new foods from whey as well as the improvement of the nutritional and organoleptic properties of the final products prepared with cheese, and thus reducing the microbial load and obtaining a safe product could be incorporated in the cheese whey valorization process.

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