Influence of foreign salts to the CaCO3-CO2-H2O system and antiscalants on the adherence of calcium carbonate on the stainless steel

2010 ◽  
Vol 41 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Ilhem Ben Salah ◽  
Mohamed Mouldi Tlili ◽  
Mohamed Ben Amor
Keyword(s):  
Stainless Steel ◽  
Calcium Carbonate

The Study of Calcium Carbonate Scaling on Low Energy Surfaces

2010 ◽  
Author(s):  
Xiuhua Si ◽  
Jinxiang Xi ◽  
Xihai Tao
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Calcium Carbonate ◽  
Surface Energy ◽  
Low Energy ◽  
Chemical Methods ◽  
Steel Surfaces ◽  
Energy Surfaces ◽  
Calcium Carbonate Scale ◽  
Scale Deposition

Scale deposition on heat transfer surfaces from water containing dissolved salts reduces the efficiency and performance of heat transfer equipments considerably. Scale deposition could be reduced through physical or chemical methods. In some cases, chemical methods are unacceptable, due to cost, contamination issues, etc. In these cases, physical methods are the only acceptable choices. Surface energy of the heat exchanger has been thought to be one important factor affecting the growth of fouling. Applying low energy surfaces to reduce scaling deposition is one of the effective physical methods. The formation and the characteristics of the calcium carbonate scaling on low energy surfaces have been studied in this paper. Copper and stainless steel surfaces were modified by micro-scale (μm thickness) PTFE (Poly-Tetrofluorethylene) films and nano-scale (nm thickness) thiolate SAMs (Self-Assembly Monolayers). The resulting surface energy of PTFE films and SAMs layers based on copper and stainless steel were significantly reduced compared with the original metal surfaces. To study the formation of the calcium carbonate scale, a recirculation cooling water system was used. The formation of the calcium carbonate scale on PTFE surfaces, SAMs surfaces, polished copper surfaces, and polished stainless steel surfaces were investigated respectively. The rate of calcium carbonate scale formation was decreased and the induction period was prolonged with the decrease of the heat transfer surface energy. The characteristics of the calcium carbonate scale formed on heat transfer surfaces with different surface energies was analyzed with fractal theory after taking photos with SEM (Scanning Electron Microscope). The fractal dimension values of the calcium carbonate scale on different heat transfer surfaces with different surface energies were calculated. The results showed that the fractal dimension values of calcium carbonate scale formed on lower energy PTFE and Cu-SAMs surfaces were greater than those that formed on higher energy Cu and stainless steel surfaces. Results of this study clearly indicated that the formation of calcium carbonate scaling on lower energy heat transfer surfaces is reduced.

scholarly journals A Study of Hot Rolling Oil with Calcium Carbonate for Stainless Steel Process

2010 ◽  
Vol 5 (3) ◽  
pp. 181-186 ◽  
Author(s):  
Naoshi Shimotomai ◽  
Hajime Ihara ◽  
Hidetaka Nanao
Keyword(s):  
Stainless Steel ◽  
Calcium Carbonate ◽  
Hot Rolling ◽  
Rolling Oil

Experimental risk assessment of carbonate scaling in the operation of high temperature – aquifer thermal energy storage (HT-ATES) systems

2020 ◽  
Author(s):  
Hester E. Dijkstra ◽  
Cjestmir V. de Boer ◽  
Mariëlle Koenen ◽  
Jasper Griffioen
Keyword(s):  
Carbon Dioxide ◽  
Stainless Steel ◽  
Organic Matter ◽  
High Temperature ◽  
Energy Storage ◽  
Calcium Carbonate ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Calcite Precipitation ◽  
Aquifer Thermal Energy Storage

<p>High temperature - aquifer thermal energy storage (HT-ATES) is gaining momentum as sustainable option for the (seasonal) storage of heat, where geothermal heat may be one of the sources. To maximize the impact of geothermal systems, the heat produced in the summertime, which is not directly needed, can be temporarily stored in a groundwater aquifer for use in the winter. However, HT-ATES does not come without technical complications. One potential complication is carbonate scaling of the technical installation and/or the aquifer in the vicinity of the injection well. Precipitation of carbonates may occur when carbonate-saturated groundwater becomes heated, upon which the groundwater becomes increasingly supersaturated for carbonates. As part of the GEOTHERMICA project HEATSTORE, both a sampling method and an experimental set-up were developed. This experimental procedure enables the sampling and testing of groundwater from HT-ATES sites or else to determine the likelihood of calcium carbonate scaling in a HT-ATES system and, if so, identify the nature and extent.</p><p>For the HEATSTORE project, Groundwater was sampled at a HT-ATES test well drilled in Middenmeer, the Netherlands down to 370 meter depth. The sampling was done with a double walled vessel, which made it possible to maintain pressure on the water sample to prevent degassing of natural occurring dissolved gases like methane and carbon dioxide during sampling and storage, as well as preventing atmospheric contamination of the groundwater. The experiments were performed in two stainless steel autoclaves which were kept at 85 degrees Celsius for up to 5 days. Three types of experiments were performed to mimic the different components of the HT-ATES system: addition of a plate of stainless steel, addition of calcium carbonate crystals and addition of aquifer sediment. The first experiment did not show any carbonate precipitation, although geochemical modelling suggests oversaturation of calcite for the applied conditions. Calcite precipitation and recrystallization were observed only in the experiments with calcite crystal seeds added. The experiment with the aquifer sediment added to the reaction vessel, containing shell fractions and intact shells (e.g. Foraminifera), did not show calcite precipitation, neither showed the chemical analysis of the water at the end of the experiment a reduction in calcium concentration. Isotope analysis suggests that carbon dioxide was released by thermally enhanced degradation of sedimentary organic matter, which would have lowered the supersaturation of calcite.</p><p>These results suggest that aquifers, in which calcite is already present and limited (or no reactive) organic matter is available, could face a risk of scaling and subsequent injectivity/productivity issues when HT-ATES is applied in these aquifers. A proper water treatment, such as the addition of carbon dioxide or hydrochloric acid to the groundwater abstracted prior to heating, could be required to prevent groundwater from getting supersaturated with carbonate minerals.</p>

Sample Contamination from Grinding and Sieving Determined by Emission Spectrometry

1970 ◽  
Vol 24 (2) ◽  
pp. 210-219 ◽  
Author(s):  
Geoffrey Thompson ◽  
Donald C. Bankston
Keyword(s):  
Stainless Steel ◽  
Calcium Carbonate ◽  
Boron Carbide ◽  
Tungsten Carbide ◽  
Trace Element ◽  
Size Fraction ◽  
Alumina Ceramic ◽  
Emission Spectrometry ◽  
Cross Contamination ◽  
Sample Contamination

The trace element contaminations, introduced by grinding or sieving samples of Specpure silica and calcium carbonate in various devices in common usage, have been measured using emission spectrometry. The tungsten carbide vial introduced large amounts of Co and Ti. The alumina mortar introduced Al, Cr, Fe, Ga, and Zr. The alumina-ceramic vial introduced Al, Cu, Fe, Ga, Li, Ti, B, Ba, Co, Mn, Zn, and Zr. The boron carbide mortar (except for B), the agate mortar, and the Lucite grinding vials introduced little or no contamination, as did sifting with nylon sieves. Stainless steel or brass sieves introduced appreciable levels of Co, Cu, Fe, Mn, Ni, Pb, Sn, and Zn. The contamination Cu, Pb, and Zn from sieving with the brass was greatest in the smaller size fraction. Pregrinding an aliquot of the sample is recommended. Greater reductions in contamination from the grinding material were noted by pregrinding with soft fine CaCO3 than with SiO2. Cross contamination from previously ground samples was demonstrated to be a major source of contamination. Grinding with the hard, more abrasive SiO2 removed more of the cross contaminants than did the CaCO3.

Reducing Scale Deposition by Surface Modification and Magnetic Water Treatment

2009 ◽  
Author(s):  
Xiuhua Si ◽  
Sungmin Youn ◽  
Jinxiang Xi
Keyword(s):  
Stainless Steel ◽  
Calcium Carbonate ◽  
Surface Energy ◽  
Induction Period ◽  
Chemical Methods ◽  
Modified Surfaces ◽  
Steel Surfaces ◽  
Calcium Carbonate Scale ◽  
Scale Deposition ◽  
Magnetic Water

Scale deposition (or fouling) on metal surfaces from salt-containing water considerably reduces the efficiency and performance of heat transfer equipments. In industrial practices, scale deposition could be reduced through physical or chemical methods. However, in some cases chemical methods are unpractical due to cost and contamination issues, rendering the physical methods the only feasible options. The objective of this study was to evaluate the effectiveness of two physical treatments in reducing scale depositions. One is to decrease the surface energy of the heat exchanger wall through surface modification; the other one is to change the crystallography of the small solid particles formed in the solution by applying a magnetic field. For the first method, the scale deposition on PTFE surfaces, SAMs (self-assembly monolayers) surfaces, polished copper surfaces, and polished stainless steel surfaces are investigated respectively. Copper and stainless steel surfaces were modified by micro-scale (μm thickness) PTFE (Poly-Tetrofluorethylene) films and nano-scale (nm thickness) thiolate SAMs. The surface energy of PTFE films and SAMs layers based on copper and stainless steel were significantly reduced compared with the untreated metal surfaces. To study the magnetic treatment effect on the formation of the calcium carbonate scale, a magnetic field up to 0.6 T was implemented in a simulated recirculation cooling water system. A large number of experiments were performed to study the effects of fluid velocity, heat flux, and the bulk concentration of the solution on the fouling rate and induction period of calcium carbonate on various modified surfaces. The experiments showed that the formation rate of the calcium carbonate scale was decreased on modified surfaces and the induction period was prolonged with the decrease of the surface energy. The study also showed that the nucleation and nucleate growth of calcium carbonate particles were enhanced through magnetic water treatment. In addition, using a higher flow rate and/or filtration of suspended calcium carbonate particles achieves a longer induction period.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

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