Effect of High-Temperature Corrosion on the Service Life of P91 Piping in Biomass Co-firing

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
C. P. O'Hagan ◽  
R. A. Barrett ◽  
S. B. Leen ◽  
R. F. D. Monaghan
Keyword(s):  
Tube Wall ◽  
Thermal Power ◽  
Creep Damage ◽  
High Temperature Corrosion ◽  
Corrosion Mechanism ◽  
Creep Life ◽  
Sem Images ◽  
X Ray ◽  
Superheater Tube ◽  
Wall Loss

Co-firing biomass with traditional fuels is becoming increasingly relevant to thermal power plant operators due to increasingly stringent regulations on greenhouse gas emissions. It has been found that when biomass is co-fired, an altered ash composition is formed, which leads to increased levels of corrosion of the superheater tube walls. Synthetic salt, which is representative of the ash formed in the co-firing of a 70% peat and 30% biomass mixture, has been produced and applied to samples of P91 at 540 °C for up to 28 days. This paper presents results for oxide layer thickness and loss of substrate from testing. Scanning electron microscopy (SEM) images and energy-dispersive X-ray spectroscopy (EDX) element maps are obtained and presented in order to gain an understanding of the complex corrosion mechanism which occurs. A finite-element (FE) methodology is presented which combines corrosion effects with creep damage in pressurized tubes. The effects of corrosion tube wall loss and creep damage on tube stresses and creep life are investigated.

Effect of High Temperature Corrosion on the Service Life of P91 Piping in Biomass Co-Firing

2015 ◽  
Author(s):  
C. P. O’Hagan ◽  
R. A. Barrett ◽  
S. B. Leen ◽  
R. F. D. Monaghan
Keyword(s):  
Fossil Fuels ◽  
Tube Wall ◽  
Rupture Life ◽  
Thermal Power ◽  
Creep Damage ◽  
Corrosion Mechanism ◽  
Sem Images ◽  
Carbon Footprints ◽  
Superheater Tube ◽  
Wall Loss

Co-firing biomass with fossil fuels is increasingly relevant to thermal power plant operators due to new, stricter sanctions relating to carbon footprints. It has been found that the use of biomass results in an altered ash composition, which leads to increased corrosion of the superheater tube walls. This paper presents results for corrosion depth, from initial testing on P91 samples exposed to synthetic salts representative of ash compositions obtained from operational plants. SEM images and EDX element maps are obtained and presented in order to gain an understanding of the complex corrosion mechanism which occurs. A finite element methodology is presented for combined corrosion with creep damage to assess the effect of corrosion tube wall loss on creep rupture life for pressurized tubes.

Comparison of Creep Damage Appearances Among Low Alloy Steel Pipes

2007 ◽  
Author(s):  
Toshiki Mitsueda ◽  
Kazuya Fujii ◽  
Somei Ohnuki
Keyword(s):  
Thermal Power ◽  
Creep Damage ◽  
Life Assessment ◽  
Creep Life ◽  
Creep Tests ◽  
Steel Pipes ◽  
Characteristic Features ◽  
Assessment Standard ◽  
Remaining Life Assessment ◽  
Internal Pressures

To establish a remaining life assessment standard for aged thermal power boilers, internal pressure creep tests of representative low alloy pipe steels were conducted. The tested materials were 2.25Cr-1Mo steel, 1Cr-0.5Mo steel, and 0.5Mo steel. Specimens with and without welded parts in their trunks were made of each material and were φ 70 mm-L400mm-t15mm in dimension. Creep test conditions were 570–620°C × 59MPa and internal pressures were applied by Argon gas or water vapor. Creep tests were interrupted at intervals to acquire data on the crept material as creeping progressed. The observations of replicas from the specimen surface showed the characteristic features of each and the following results were obtained from the comparison of them. (1) The specimens of 2.25Cr-1Mo steel and 1Cr-0.5Mo steel suddenly expanded at about 80% of creep life ratio, and that of 0.5Mo gradually expanded from 60%. They finally ruptured with 15–20% expansions in diameter. (2) Although 2.25Cr-1Mo steel witnessed few creep voids near the end of its creep life, 1 Cr-0.5Mo steel and 0.5Mo steel witnessed many voids such as microcracks from mid-creep life onward. (3) Deformation of ferrite grains contributed to the expansion of 2.25Cr-1Mo steel specimens. On the other hand, partial separations of grains seem to have been owed to the expansions of 1Cr-0.5Mo steel and 0.5Mo steel. In 2.25Cr-1Mo steel, the strength of grain boundary versus grain interior seems to be higher than those of 1Cr-0.5Mo steel and 0.5Mo steels. (4) The amount of creep voids in the HAZ of 1.5Cr-0.5Mo steel was roughly three times that of 2.25Cr-1Mo steel.

scholarly journals Sulphur and vanadium-induced high-temperature corrosion behaviour of different regions of SMAW weldment in ASTM SA 210 GrA1 boiler tube steel

2020 ◽  
Vol 39 (1) ◽  
pp. 256-260
Author(s):  
Ravindra Kumar ◽  
Vinay Kumar Tewari ◽  
Satya Prakash
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Power Plants ◽  
Corrosion Behaviour ◽  
Thermal Power ◽  
High Temperature Corrosion ◽  
Tube Steel ◽  
Low Grade ◽  
Shielded Metal Arc Welding ◽  
X Ray

AbstractCorrosion at elevated temperature is a serious problem in running thermal power plants because of the use of low-grade fuels that contain substantial amounts of sulphur, vanadium, sodium etc. This article reports the high-temperature corrosion of weld metal and heat-affected zone (HAZ) of shielded metal arc-welding (SMAW) weldment in GrA1 steel in a molten salt (Na2SO4–60% V2O5) environment at 900°C under cyclic conditions. The thermogravimetric technique was used to observe the kinetics of corrosion. The corrosion products formed on weld metal and HAZ of SMAW welded steel were characterized by scanning electron microscopy with energy dispersive X-ray analysis (EDX) and X-ray diffraction pattern. Weld metal was found to oxidize at a higher rate than those of HAZ due to the presence of sodium and sulphur in the inner oxide scale as confirmed by EDX, and this leads to high corrosion rate (in terms of weight gain).

Mosaic Mapping: A Means of Tiling Images to Shorten Acquisition Speed for Lower - Magnification SEM Images and Wavelength Dispersive Spectrometers (WDS) X-Ray Maps

1996 ◽  
Vol 54 ◽  
pp. 438-439
Author(s):  
J.D. Geller ◽  
C.R. Herrington
Keyword(s):  
Limiting Factors ◽  
X Rays ◽  
Angular Range ◽  
Acceptance Angle ◽  
Sem Images ◽  
Worst Case ◽  
X Ray ◽  
Focusing Distance ◽  
Layered Crystals ◽  
Working Distance

The minimum magnification for which an image can be acquired is determined by the design and implementation of the electron optical column and the scanning and display electronics. It is also a function of the working distance and, possibly, the accelerating voltage. For secondary and backscattered electron images there are usually no other limiting factors. However, for x-ray maps there are further considerations. The energy-dispersive x-ray spectrometers (EDS) have a much larger solid angle of detection that for WDS. They also do not suffer from Bragg’s Law focusing effects which limit the angular range and focusing distance from the diffracting crystal. In practical terms EDS maps can be acquired at the lowest magnification of the SEM, assuming the collimator does not cutoff the x-ray signal. For WDS the focusing properties of the crystal limits the angular range of acceptance of the incident x-radiation. The range is dependent upon the 2d spacing of the crystal, with the acceptance angle increasing with 2d spacing. The natural line width of the x-ray also plays a role. For the metal layered crystals used to diffract soft x-rays, such as Be - O, the minimum magnification is approximately 100X. In the worst case, for the LEF crystal which diffracts Ti - Zn, ˜1000X is the minimum.

scholarly journals Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry
Keyword(s):  
New Mexico ◽  
Surface Area ◽  
Bet Surface Area ◽  
Lead Removal ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Naturally Occurring ◽  
27Al Mas Nmr ◽  
Modified Zeolites

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.

scholarly journals Creep Damage Repair of a Nickel-Based Single Crystal Superalloy Based on Heat Treatment

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 623
Author(s):  
Xiaoyan Wang ◽  
Meng Li ◽  
Yuansheng Wang ◽  
Chengjiang Zhang ◽  
Zhixun Wen
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Creep Damage ◽  
Primary Creep ◽  
Single Crystal Superalloy ◽  
Secondary Creep ◽  
Creep Life ◽  
Phase Coarsening ◽  
Damage Repair ◽  
Creep Time

Taking nickel-based single crystal superalloy DD6 as the research object, different degrees of creep damage were prefabricated by creep interruption tests, and then the creep damage was repaired by the restoration heat treatment system of solid solution heat treatment and two-stage aging heat treatment. The results show that with the creep time increasing, the alloy underwent microstructure evolution including γ′ phase coarsening, N-type rafting and de-rafting. After the restoration heat treatment, the coarse rafted γ′ phase of creep damaged specimens dissolved, precipitated, grew up, and became cubic again. Except for the specimens with creep interruption of 100 h, the γ′ phase can basically achieve the same arrangement as the γ′ phase of the original sample. The comparison of the secondary creep test shows that the steady-state creep stage of the test piece after the restoration heat treatment is relatively increased, and the total creep life can reach the same level as the primary creep life. The high temperature creep properties of the tested alloy are basically recovered, and the restoration heat treatment effect is good.

scholarly journals Toxicity and Biological Effects of Beauveria brongniartii Fe0 Nanoparticles against Spodoptera litura (Fabricius)

Insects ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 895
Author(s):  
Jing Xu ◽  
Kaihui Zhang ◽  
Andrew G. S. Cuthbertson ◽  
Cailian Du ◽  
Shaukat Ali
Keyword(s):  
Spodoptera Litura ◽  
Insect Pests ◽  
Growth Parameters ◽  
Uv Spectroscopy ◽  
Biological Effects ◽  
Fungal Treatment ◽  
Beauveria Brongniartii ◽  
Sem Images ◽  
X Ray ◽  
Infection Period

Nanotechnology has clear potential in the development of innovative insecticidal products for the biorational management of major insect pests. Metal-based nanoparticles of different microbial pest control agents have been effective against several pests. Synthesis of Beauveria brongniartii based Fe0 nanoparticles (Fe0NPs) and their bio-efficacy against Spodoptera litura was observed during this study. Beauveria brongniartii conidia were coated with Fe0NPs and characterized by applying a selection of different analytical techniques. Ultraviolet (UV) spectroscopy showed the characteristic band of surface plasmon at 430 nm; Scanning electron microscopy (SEM) images showed spherical shaped nanoparticles with a size ranging between 0.41 to 0.80 µm; Energy-dispersive X-ray (EDX) spectral analysis revealed characteristic Fe peaks at 6.5 and 7.1 Kev; the X-ray diffractogram showed three strong peaks at 2θ values of 45.72°, 64.47°, and 84.05°. The bioassay studies demonstrated that mortality of 2nd instar S. litura larvae following Fe0NPs treatment increased with increasing concentrations of Fe0NPs at different time intervals. The median lethal concentration (LC50) values of Fe0NPs against S. litura after seven days of fungal treatment was 59 ppm, whereas median survival time (LT50) values for 200 and 500 ppm concentrations of Fe0NPs against S. litura seven days post-treatment were 5.1 and 2.29 days, respectively. Beauveria brongniartii-Fe0NPs caused significant reductions in feeding and growth parameters (relative growth rate, relative consumption rate, and efficiency of conversion of ingested food) of S. litura. Beauveria brongniartii Fe0NPs induced reduction in glutathione-S-transferase activities throughout the infection period whereas activities of antioxidant enzymes decreased during later periods of infection. These findings suggest that B. brongniartii Fe0NPs can potentially be used in biorational S. litura management programs.

scholarly journals Preparation of Synthetic Zeolites from Coal Fly Ash by Hydrothermal Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1267
Author(s):  
David Längauer ◽  
Vladimír Čablík ◽  
Slavomír Hredzák ◽  
Anton Zubrik ◽  
Marek Matik ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Combustion ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Product Analysis ◽  
Coal Combustion Products ◽  
X Ray ◽  
Wide Range ◽  
Silica Alumina

Large amounts of coal combustion products (as solid products of thermal power plants) with different chemical and physical properties cause serious environmental problems. Even though coal fly ash is a coal combustion product, it has a wide range of applications (e.g., in construction, metallurgy, chemical production, reclamation etc.). One of its potential uses is in zeolitization to obtain a higher added value of the product. The aim of this paper is to produce a material with sufficient textural properties used, for example, for environmental purposes (an adsorbent) and/or storage material. In practice, the coal fly ash (No. 1 and No. 2) from Czech power plants was firstly characterized in detail (X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), particle size measurement, and textural analysis), and then it was hydrothermally treated to synthetize zeolites. Different concentrations of NaOH, LiCl, Al2O3, and aqueous glass; different temperature effects (90–120 °C); and different process lengths (6–48 h) were studied. Furthermore, most of the experiments were supplemented with a crystallization phase that was run for 16 h at 50 °C. After qualitative product analysis (SEM-EDX, XRD, and textural analytics), quantitative XRD evaluation with an internal standard was used for zeolitization process evaluation. Sodalite (SOD), phillipsite (PHI), chabazite (CHA), faujasite-Na (FAU-Na), and faujasite-Ca (FAU-Ca) were obtained as the zeolite phases. The content of these zeolite phases ranged from 2.09 to 43.79%. The best conditions for the zeolite phase formation were as follows: 4 M NaOH, 4 mL 10% LiCl, liquid/solid ratio of 30:1, silica/alumina ratio change from 2:1 to 1:1, temperature of 120 °C, process time of 24 h, and a crystallization phase for 16 h at 50 °C.

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