Analysis of Piping Systems for Life Extension of Heavy Water Plants in India

2002 ◽  
Author(s):  
Rajesh K. Mishra ◽  
R. S. Soni ◽  
H. S. Kushwaha ◽  
V. Venkat Raj
Keyword(s):  
Thermal Expansion ◽  
Heavy Water ◽  
Past History ◽  
Plant Performance ◽  
Life Extension ◽  
The Past ◽  
Piping Systems ◽  
Sustained Loads ◽  
High Fatigue ◽  
Water Plants

Heavy water production in India has achieved many milestones in the past. Two of the successfully running heavy water plants are on the verge of completion of their design life in the near future. One of these two plants, situated at Kota, is a hydrogen sulfide based plant and the other one at Tuticorin is an ammonia-based plant. Various exercises have been planned with an aim to assess the fatigue usage for the various components of these plants in order to extend their life. Considering the process parameters and the past history of the plant performance, critical piping systems and equipment are identified. Analyses have been carried out for these critical piping systems for mainly two kinds of loading, viz. sustained loads and the expansion loads. Static analysis has been carried out to find the induced stress levels due to sustained as well as thermal expansion loading as per the design code ANSI B31.3. Due consideration has been given to the design corrosion allowance while evaluating the stresses due to sustained loads. At the locations where the induced stresses (SL) due to the sustained loads are exceeding the allowable limits (Sh), exercises have been carried out considering the reduced corrosion allowance value. This strategy is adopted in view of the fact that the thickness measurements carried out at site at various critical locations show a very low rate of corrosion. It has been possible to qualify the system with reduced corrosion allowance values however, it is recommended to keep that location under periodic monitoring. The strategy adopted for carrying out analysis for thermal expansion loading is to qualify the system as per the code allowable value (Sa). If the stresses are more than the allowable value, credit of liberal allowable value as suggested in the code i.e., with the addition of the term (Sh-SL) to the term 0.25 Sh, has been taken. However, if at any location, it is found that thermal stress is high, fatigue analysis has been carried out. This is done using the provisions of ASME Code Section VIII, Div. 2 by evaluating the cumulative fatigue usage factor. Results of these exercises reveal that the piping systems of both of these plants are in a very healthy state. Based on these exercises, it has been concluded that the life of the plants can be safely extended further with enhanced in-service inspection provisions.

Computer Based Process Piping Stress Analysis: ASME B31.3 Appendix S — Example S2

2006 ◽  
Author(s):  
Don R. Edwards
Keyword(s):  
Stress Analysis ◽  
Operating Temperature ◽  
Stress Range ◽  
Explicit Equation ◽  
The Past ◽  
Process Piping ◽  
Piping Systems ◽  
Sustained Loads ◽  
Computer Based ◽  
Temperature And Pressure

The American Standards Association (ASA) B31.3-1959 Petroleum Refinery Piping Code [1] grew out of an ASA document that addressed all manner of fluid conveying piping systems. ASA B31.3 was created long before widespread engineering use of computer “mainframes” or even before the inception of piping stress analysis software. Also as B31.3 continued to pass thru standards organizations from ASA, ANSI, to ASME, the B31.3 Process Piping Code [2] (hereafter referred to as the “Code”) has remained ambiguous over the past few decades in several areas. The displacement stress range, SE, has always been explicitly defined by both verbiage and equation. Yet, the sustained condition(s) stress, SL, is mentioned not with an explicit equation but with a statement that the sustained stress shall be limited by the allowable stress at the corresponding operating temperature, Sh. Also one might infer from the vague verbiage in the Code that there is only one sustained condition; this would also be an incorrect inference. Also, assumptions would then have to be made as to which supports are allowed to be included in a sustained analysis based on whether the piping “lifts-off” any of the pipe supports during the corresponding operating condition. This paper describes the subtle yet possibly radical concepts that are included in the (recently approved for inclusion into) ASME B31.3-2006 Appendix S Example S2. This paper discusses: • when and in what manner the most severe set of operating temperature and pressure is to be used; • the concept of “sustained condition” and multiple “anticipated” sustained conditions; • determining the support scenario(s) for each anticipated sustained condition; • establishing the most severe sustained condition to evaluate and determine the stress due to sustained loads, SL; • utilizing an equation with sustained stress indices to evaluate SL; • establishing the least severe sustained condition and its effect in determining the largest displacement stress range, SE.

A New Shape of Expansion Loop to Compensate Thermal Expansion of Piping Systems

2009 ◽  
Author(s):  
Aurel M. Alessandrescu
Keyword(s):  
Thermal Expansion ◽  
Heavy Water ◽  
Operating Conditions ◽  
Piping System ◽  
Analysis Program ◽  
Alternative Compensation ◽  
Pipe Expansion ◽  
Water Plant ◽  
Piping Systems ◽  
Asme Code

To provide the piping system self-compensation under the conditions in which lenticular thermal pipe expansion devices cannot be used due to the crack induced corrosion (e.g.in the Heavy Water Plant) is accomplished by special devices (e.g. U,L,Z type). Under such circumstances a novative alternative compensation solution was implemented, namely, the employment of ROTATING Z type or AA (VΛ). Such a type of compensation consists in 2× 90° pipe bends and 2× 45° pipe bends. Calculations of 15 alternative compensation solutions with more over 120 variants of materials, nominal diameter, operating conditions (Po, To) were made by running CaePipe 5.15 analysis program for 3 cases: sustained, thermal expansion and operating. The stress and distorsion conditions of the new shape satisfied the requirements in ASME Code B31.3 evidencing that this shape provides the most favorable results.

Developing Stress Intensification Factors for Composite Repair Systems Used to Repair Damaged Pipe

2010 ◽  
Author(s):  
Chris Alexander
Keyword(s):  
Composite Materials ◽  
Extensive Study ◽  
Life Extension ◽  
Composite Repair ◽  
The Past ◽  
Extensive Evaluation ◽  
Research Organizations ◽  
Piping Systems ◽  
Repair Systems ◽  
Girth Welds

For the better part of the past 15 years composite materials have been used to repair corrosion in high pressure gas and liquid transmission pipelines. This method of repair is widely accepted throughout the pipeline industry because of the extensive evaluation efforts performed by composite repair manufacturers, operators, and research organizations. Pipeline damage comes in different forms, one of which involves dents that include plain dents, dents in girth welds and seam welds. An extensive study has been performed over the past several years involving multiple composite manufacturers that installed their repair systems on the above mentioned dent types. The test samples were pressure cycled to failure to determine the level of life extension provided by the composite materials over a set of unrepaired test samples. Several of the repaired dents in the study did not fail even after 250,000 pressure cycles had been applied at a range of 72% SMYS. The primary purpose of this paper is to present details on how Stress Intensification Factors were derived using the empirically-generated data. The results of this study clearly demonstrate the significant potential that composite repair systems have, when properly designed and installed, to restore the integrity of damaged pipelines and piping systems to ensure long-term service.

Use of chemical upgrading (CU) in Hungary and Slovakia

1994 ◽  
Vol 30 (5) ◽  
pp. 87-95 ◽  
Author(s):  
Susan E. Murcott ◽  
Donald R. F. Harleman
Keyword(s):  
Wastewater Treatment ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Domestic Sewage ◽  
Metal Salts ◽  
Plant Performance ◽  
Eastern European ◽  
Low Doses ◽  
The Past ◽  
Treatment Technologies

In the past decade, the development of polymers and new chemical technologies has opened the way to using low doses of chemicals in wastewater treatment. “Chemical upgrading” (CU) is defined in this paper as an application of these chemical technologies to upgrade overloaded treatment systems (typically consisting of conventional primary plus biological treatment) in Central and Eastern European (CEE) countries. Although some of the chemical treatment technologies are proven ones in North America, Scandinavia, and Germany, a host of factors, for example, the variations in composition and degree of pollution, the type of technologies in use, the type and mix of industrial and domestic sewage, and the amount of surface water, had meant that the viability of using CU in CEE countries was unknown. This report describes the first jar tests of CU conducted during the summer of 1993. The experiments show CU's ability to improve wastewater treatment plant performance and to potentially assist in the significant problem of overloaded treatment plants. Increased removal of BOD, TSS, and P in the primary stage of treatment is obtained at overflow rates above 1.5 m/h, using reasonably priced, local sources of metal salts in concentrations of 25 to 50 mg/l without polymers.

Obituary notices of fellows deceased

1877 ◽  
Vol 25 (171-178) ◽  
Keyword(s):  
Past History ◽  
The Past ◽  
The Earth ◽  
History Of ◽  
Reign Of Terror ◽  
Accurate Observation

George Poulett Scrope. It is scarcely possible at the present day to realize the conditions of that intellectual “reign of terror” which prevailed at the commencement of the present century, as the consequence of the unreasoning prejudice and wild alarm excited by the early progress of geological inquiry. At that period, every attempt to explain the past history of the earth by a reference to the causes still in operation upon it was met, not by argument, but by charges of atheism against its propounder; and thus Hutton’s masterly fragment of a ‘Theory of the Earth,’ Playfair’s persuasive‘ Illustrations,’ and Hall’s records of accurate observation and ingenious experiment had come to be inscribed m a social Index Expurgatorius ,and for a while, indeed, might have seemed to be consigned to total oblivion. Equally injurious suspicions were aroused against the geologist who dared to make allusion to the important part which igneous forces have undoubtedly played in the formation of certain rocks; for the authority of Werner had acquired an almost sacred cha­racter; and “ Vulcanists ” and “ Huttonians ” were equally objects of aversion and contempt. To two men who have very recently—and within a few months of one another—passed away from our midst, science is indebted for boldly en­countering and successfully overcoming this storm of prejudice. Hutton and his friends lived a generation too soon ; and thus it was reserved tor Lyell and Scrope to carry out the task which the great Scotch philosopher had failed to accomplish, namely, the removal of geology from the domain of speculation to that of inductive science.

Colonising the Past? History, Medicine, and Reality Television

2006 ◽  
Vol 8 (2) ◽  
pp. 124-146
Author(s):  
Susan Hardy ◽  
Anthony Corones
Keyword(s):  
Reality Television ◽  
Past History ◽  
The Past

Preserve the past [history - architecture]

2021 ◽  
Vol 16 (11) ◽  
pp. 46-49
Author(s):  
H. Pozniak
Keyword(s):  
Past History ◽  
The Past
Sign in / Sign up

Export Citation Format

Share Document