Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Industrial and Institutional Boilers

2022 ◽  
Author(s):  
Keyword(s):  
Water Chemistry ◽  
Cross Section ◽  
Chemical Treatment ◽  
Research Committee ◽  
Thermal Systems ◽  
Boiler Water ◽  
Additional Information ◽  
Water Conditioning ◽  
Industrial Boilers ◽  
Boiler Design

The Water Technology Subcommittee of the ASME Research and Technology Committee on Water and Steam in Thermal Systems, under the leadership of Mr. Robert D. Bartholomew has revised the Consensus on Operating Practices for the Control of Feedwater Boiler Water Chemistry in Modern Industrial Boilers, first published in 1979 with prior revisions published in 1994 and 1998. The task group consisted of a cross section of manufacturers, operators, chemical treatment contractors and consultants involved in the fabrication and operation of industrial and institutional boilers. Members of this group are listed in the acknowledgments. This current document is an expansion and revision of the original, with reordered and modified texts where considered necessary. While significant revisions have been incorporated, it is recognized that there are areas of operating practice not addressed herein. Additional information is available from the references. It is the plan of the ASME Research Committee to continue to review this information, and revise and reissue this document as necessary to comply with advances in boiler design and water conditioning technology.

Section 1. Introduction

2022 ◽  
pp. 1-2
Author(s):  
Keyword(s):  
Water Chemistry ◽  
Steam Generators ◽  
Thermal Systems ◽  
Boiler Water ◽  
System Components ◽  
Steam System ◽  
Current Operating

This document has been prepared by the Water Technology Subcommittee of the ASME Research and Technology Committee on Steam and Water in Thermal Systems as a consensus of proper current operating practices for the control of feedwater and boiler water chemistry in the operation of industrial and institutional, high duty, primary fuel fired boilers. These practices are aimed at minimizing corrosion, deposition, cleaning requirements, and unscheduled outages in the steam generators and associated condensate, feedwater and steam systems for boilers, and steam system components which are currently available. This publication is an expansion and revision of the operating practice consensus documents previously issued by the Committee [1-3]. The tabulated values herein update and replace the ones previously published. Titles have been edited and clarified. The text has been reordered and modified where necessary. THE TEXT IS OF PRIME IMPORTANCE AND SHOULD BE CONSIDERED FULLY BEFORE USING THE TABULATED VALUES. One Appendix has been added to provide additional guidance.

Section 4. Water Chemistry Parameters

2022 ◽  
pp. 14-27
Author(s):  
Keyword(s):  
Water Chemistry ◽  
Sample Collection ◽  
Boiler Water ◽  
Record Keeping ◽  
Grab Sample ◽  
Industrial Boilers

The maintenance of specified feedwater and boiler water chemistry must be well regulated and documented by frequent analysis and record keeping. Normally, a combination of online analyzers and grab sample measurements is used to ensure proper chemistry control. Guidance on sample collection and conditioning is provided in “Consensus on Operating Practices for the Sampling and Monitoring of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers” [7].

Section 5. Tables of Suggested Water Chemistry Targets

2022 ◽  
pp. 28-30
Author(s):  
Keyword(s):  
Water Chemistry ◽  
Steam Generator ◽  
Prime Factor ◽  
Operating Pressure ◽  
Boiler Water ◽  
Water Contaminant ◽  
Internal Water ◽  
Boiler Drum ◽  
The Difference

Consensus water chemistry controls for the six types of steam generator systems are presented in Tables 1 through 7. The tabulated information is categorized according to operating pressure ranges because this is the prime factor that dictates the type of internal water chemistry employed, the normal cycles of feedwater concentration, the silica volatility, and the carryover tendency. The difference between steam and water densities decreases with increasing pressure and temperature; therefore, separating the steam/water phases completely in the boiler drum becomes increasingly difficult to achieve. Since the tendency to carryover is greater at higher operating pressures, it is necessary to maintain lower boiler water contaminant concentrations to meet the same steam purity target.

Estimation of Nusselt Number in Microchannels of Arbitrary Cross-Section With Constant Axial Heat Flux

2008 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Majid Bahrami ◽  
Ned Djilali
Keyword(s):  
Heat Flux ◽  
Nusselt Number ◽  
Cross Section ◽  
Cross Sections ◽  
Numerical Solutions ◽  
Arbitrary Cross Section ◽  
Geometrical Parameters ◽  
Thermal Systems ◽  
Cross Sectional ◽  
Axial Heat

In many practical instances such as basic design, parametric study, and optimization analysis of thermal systems, it is often very convenient to have closed form relations to obtain the trends and a reasonable estimate of the Nusselt number. However, finding exact solutions for many practical singly-connected cross-sections, such as trapezoidal microchannels, is complex. In the present study, the square root of cross-sectional area is proposed as the characteristic length scale for Nusselt number. Using analytical solutions of rectangular, elliptical, and triangular ducts, a compact model for estimation of Nusselt number of fully-developed, laminar flow in microchannels of arbitrary cross-sections with “H1” boundary condition (constant axial wall heat flux with constant peripheral wall temperature) is developed. The proposed model is only a function of geometrical parameters of the cross-section, i.e., area, perimeter, and polar moment of inertia. The present model is verified against analytical and numerical solutions for a wide variety of cross-sections with a maximum difference on the order of 9%.

Effects of SO42− concentration on corrosion behaviour of carbon steels

2015 ◽  
Vol 62 (5) ◽  
pp. 322-326 ◽  
Author(s):  
Zhiping Zhu ◽  
Xiaocui Jiao ◽  
Xueying Tang ◽  
Haiwei Lu
Keyword(s):  
Water Chemistry ◽  
Pitting Corrosion ◽  
Design Methodology ◽  
Competitive Adsorption ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Carbon Steels ◽  
Boiler Water ◽  
Content Type ◽  
Condition Solution

Purpose – The purpose of this paper was to investigate the effects of SO42− concentration on the corrosion behaviour of T23 and T12 steels in simulated water chemistry condition solution of 600 MW fossil-fired power boilers. Design/methodology/approach – The influence and mechanism of SO42− ions on the pitting corrosion of T23 and T12 steels in simulated oxygenated treatment water chemistry solution was studied using electrochemical potentiodynamic polarization scans and electrochemical impedance spectroscopy. Findings – The results showed that T23 and T12 were susceptible to pitting corrosion in the simulated solution with full SO42− concentration for the competitive adsorption of OH− and SO42− on the surface of steels. The pitting sensitivity of the steels improved with increasing SO42− concentration. The corrosion resistance for SO42− of T23 was stronger than that for T12. Originality/value – This study is an attempt to provide direction for regulating the concentration of SO42− in boiler water and for selecting the material for boiler water wall tubes.

Minimum Standards for the Description of Participants in Learning Disabilities Research

1994 ◽  
Vol 15 (1) ◽  
pp. 56-59 ◽  
Author(s):  
Michael S. Rosenberg ◽  
Deborah Bott ◽  
David Majsterek ◽  
Bert Chiang ◽  
Deborah Simmons ◽  
...  
Keyword(s):  
Learning Disabilities ◽  
Small Sample ◽  
Research Committee ◽  
Additional Information ◽  
Minimum Standards ◽  
Ongoing Process ◽  
Research Activities ◽  
Group Research ◽  
Research Findings ◽  
One Step

In 1984, the research committee of the council for learning disabilities (CLD) noted that the available descriptions of individuals with LD in research reports were vague and inconsistent. Recognizing that such descriptions made it difficult to evaluate research findings, the committee recommended that specific guidelines for participant descriptions be followed in reports on research involving individuals with LD. Eight years after this call for greater uniformity, vague participant descriptors remain a matter of great concern. What follows is a report on this issue from the current cld research committee. Updated guidelines for the description of participants are provided for both small-sample and large-group research activities. Also, suggestions for promoting compliance with the minimum standards are forwarded. Rather than being viewed as a fixed, immutable product, the current attempt at identifying the minimum standards for the description of participants should be viewed merely as one step in an ongoing process. Clearly, as our multidisciplinary field continues to learn more about LD, additional information about participants may be deemed necessary. With this in mind, the cld research committee welcomes your comments on the present set of guidelines and invites your suggestions for future iterations of this document.

scholarly journals Deep learning the collisional cross sections of the peptide universe from a million training samples

2020 ◽  
Author(s):  
Florian Meier ◽  
Niklas D. Köhler ◽  
Andreas-David Brunner ◽  
Jean-Marc H. Wanka ◽  
Eugenia Voytik ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Peptide Sequence ◽  
Peptide Ions ◽  
Additional Information ◽  
Training Samples ◽  
Deep Recurrent Neural Network ◽  
Collisional Cross Section ◽  
Data Points ◽  
Main Determinants

ABSTRACTThe size and shape of peptide ions in the gas phase are an under-explored dimension for mass spectrometry-based proteomics. To explore the nature and utility of the entire peptide collisional cross section (CCS) space, we measure more than a million data points from whole-proteome digests of five organisms with trapped ion mobility spectrometry (TIMS) and parallel accumulation – serial fragmentation (PASEF). The scale and precision (CV <1%) of our data is sufficient to train a deep recurrent neural network that accurately predicts CCS values solely based on the peptide sequence. Cross section predictions for the synthetic ProteomeTools library validate the model within a 1.3% median relative error (R > 0.99). Hydrophobicity, position of prolines and histidines are main determinants of the cross sections in addition to sequence-specific interactions. CCS values can now be predicted for any peptide and organism, forming a basis for advanced proteomics workflows that make full use of the additional information.

Contribution to the systematic knowledge of Lamium multifidum and L. orientale (Lamiaceae)

Phytotaxa ◽  
2015 ◽  
Vol 203 (2) ◽  
pp. 147 ◽  
Author(s):  
Bayram Atasagun ◽  
Ahmet Aksoy ◽  
Esra Martin
Keyword(s):  
Chromosome Number ◽  
Cross Section ◽  
Pollen Grains ◽  
Morphological Characters ◽  
Previous Description ◽  
Somatic Chromosome Number ◽  
Additional Information ◽  
Naturally Occurring ◽  
First Time ◽  
Systematic Knowledge

Some morphological, anatomical, palynological and karyological features of Lamium multifidum and L. orientale (Lamiaceae) naturally occurring in Turkey have been studied. Additional information was added to the previous description of these species. Anatomically, both L. multifidum and L. orientale had an annual taproot, stems quadrangular in cross-section, leaves bifacial. The nutlets were ovoid in outline and trigonous in cross section, blackish-dark brownish, with glabrous surface. The pollen grains of both species were tricolpate, shape subprolate, ornamentation reticulate. In both species, the somatic chromosome number resulted 2n = 14. The anatomical and palynological features, chromosome number and morphological characters of both species were reported for the first time in this study.

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