In this work the solidÀliquid equilibrium (SLE) and freezing-point depression (FPD) in the electrolytic binary aqueous systems piperazine (PZ, and aqueous 2-amino-2-methyl-1-propanol (AMP, were measured. The FPD and solubility were also determined in the ternary AMPÀPZÀH 2 O system. A method was developed by which solubility can be determined at higher temperatures using the FPD setup. A total of 86 data points are listed in the full concentration range from (À35 to 90)°C. The solid phases piperazine hexahydrate (PZ 3 6H 2 O), piperazine hemihydrate (PZ 3 1/2H 2 O), and anhydrous PZ precipitated during the experiments. The data can be used in the formulation, prevention, or intentional formation of slurries in piperazine solvents for promoting CO 2 capture using absorption and desorption. INTRODUCTIONCO 2 capture is an openly debated topic for carbon emission reduction to reduce pollution by greenhouse gases. Process streams containing carbon dioxide can be cleaned by absorption in aqueous liquid solvents. Amines, strong bases, or combination of the two are typically used as active components. The low heats of absorption and desorption are design criteria that reduce the cost of energy in regeneration of the solvent. This is obtained by using sterically hindered amines. The result is often slow reaction kinetics between the solvent and CO 2 . Consequently piperazine (PZ) is being used in solution formulation to create an enhanced CO 2 capture solvent. PZ can be used with both amine and potash solutions (K 2 CO 3 ) to increase the rate of absorption and thereby promote the CO 2 capture.A lower PZ concentration was typically used in literature. Recently the scope has changed, and PZ is now being used at higher concentrations. On increasing the concentration, the solubility limit of PZ is being reached, especially during winter temperatures and even up to room temperature. The unexpected formation of slurries and solids downstream may create unforeseen process conditions, decrease efficiency, and create clogging which will result in unfortunate hazardous operations. In general it could be interesting to provoke the formation of CO 2 containing solids and thereby facilitate and increase the capacity of the capture solvent. CO 2 deprived solids are rarely preferable in terms of CO 2 capture.The aim of this work is to determine the solidÀliquid phase boundary in the two binary PZÀH 2 O and AMPÀH 2 O systems and also in the ternary AMPÀPZÀH 2 O system. 2-Amino-2-methyl-1-propanol (AMP) is a sterically hindered amine. CO 2 absorption in AMP solutions can be promoted by adding PZ.An additional goal of this work was to enhance the utilization of freezing-point depression (FPD) equipment developing a method for the purpose of studying solidÀliquid equilibrium (SLE) behavior in solutions precipitating solids other than ice.

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In this work the solid-liquid equilibrium (SLE) of the ternary system 2-amino-2-methyl-propanol (AMP)-piperazine (PZ)-H2O and the aqueous binary system AMP were determined using a freezing point depression (FPD) setup and differential scanning calorimetry (DSC). A total of 59 new data points are listed in the full concentration range of 0 < w(AMP) < 100 % and 0 < w(PZ) < 61 %. The SLE phase boundary of AMP tetrahydrate (AMP•4H2O) was determined and confirmed by its crystal structure obtained from powder x-ray diffraction (PXRD).The new data of this work can be used in the creation of thermodynamic model for prevention of AMP and PZ precipitates from solvents used for CO2 capture. This gives a higher degree of safe

In this work, the solid–liquid equilibrium (SLE) of the systems glycine (Gly)–H2O, Gly–NaOH–H2O, Gly–NaHCO3–H2O, and Gly–NaOH–NaHCO3–H2O was determined using a freezing point depression (FPD) setup. A total of 131 new data points are listed in the concentration range 0 < b (sodium glycinate (SG)) < 25 mol SG/kg water. The system Gly–NaOH–H2O with five different mole ratios (n NaOH:n Gly) 1:1, 1:2, 1:5, 2:1, and 5:1 and the CO2-loaded system Gly–NaOH–NaHCO3–H2O were analyzed in a loading range of 0.1–1 mol CO2 per mol SG. Eutectic points and hydrate formations were identified in the systems Gly–H2O, Gly–NaOH–H2O, and Gly–NaOH–NaHCO3–H2O. The solubility of SG increased linearly with higher concentrations for systems with an excess of NaOH. The solubility of SG decreased significantly with an excess addition of NaOH and glycine. The same trend was observed in the CO2-loaded system. The new data create a better understanding of phase equilibria in this system. This understanding is useful for the thermodynamic modeling of the system, which can potentially be used for CO2 capture. The data give a clear representation of the degree of safe operation in terms of managing a plant without solid formation.

The solid-liquid phase boundaries on new innovative solvents for the carbon capture and storage (CCS) technology have been measured in this work. The solvents have been formulated with vapour reduction additives (VRAs) also known as water lean solvents. The solid-liquid equilibrium (SLE) data will create better prediction models for the CCS technology and prevent precipitation in process equipment and thereby reduce the risk of costly shutdowns. The presented SLE data cannot be used in the prediction of solid formation in condenser as it would require knowledge of the vapour-liquid-solid equilibria. 2The SLE of the systems urea-H2O, urea-monoethanolamine (MEA)-H2O, and monoethylene glycol (MEG)-H2O have been determined using the methods freezing point depression (FPD) and SLE by FPD. 61 new SLE data points are listed of 0 < w(urea) < 60 %, and 0 < w(MEG) < 20 %.It is the first time that the ternary systems have been measured. The eutectic temperatures were found at -8 °C for urea-H2O and -27 °C for urea-MEA-H2O. Highly concentrated urea solutions freeze completely upon mixing water with MEA due to the endothermic reaction. Solubility data of MEG-MEA-H2O was found for t > -40 °C. All SLE points for MEG in 30 wt% aqueous MEA freezes below -15 °C.To avoid clogging from urea precipitation, it is recommended to use urea below 30 wt%.

FeCO3 is present as scales in process equipment, corrosion products, geological systems, and carbon storage. It is therefore crucial to investigate the properties of FeCO3 to understand scaling in all these systems. However, FeCO3 is not commercially available, and when used in the lab it is either obtained through extraction of geological formations or synthesized in-house. Geologically formed FeCO3 contains multiple impurities, which will affect its overall properties, and the synthesized product is highly sensitive to either oxidation or the synthesis pathways. This work explores the parameter space of a synthesis route routinely and pathways for FeCO3. We characterized the structure of FeCO3 using X-ray powder diffraction and its thermal properties with thermogravimetric analysis and scanning electron microscopy. We show how synthesis parameters influence either the macroscopic or microscopic properties of the synthesized product. Our study serves as a guideline for future research regarding what parameters to choose when synthesizing FeCO3 and what product can be obtained. We herein present a novel fundamental understanding of FeCO3.

Without methods for surface characterization of tubing and pipeline, corrosion and scaling cannot be mitigated. One standardized characterization method would enable comparison between various surfaces, which would give new insight into the mechanism behind both corrosion and scaling. We aim to showcase a novel surface characterization software and how it can be used for industry and research purposes. We aim to highlight the capabilities of this tool through 2 analysis campaigns. Our tool is called XCHANTO (X-ray CHannel ANalysis TOol). XCHANTO is an in-house written Python code that can extract surface texture information from 3D point cloud data generated from a stack of images. XCHANTO is based on X-ray CT scanning and calculates standardized Metrologic parameters. In the first campaign we show how XCHANTO can aid the industry in characterizing decommissioned tubing. We performed a single in-depth analysis of a channel. The investigation includes global averages of texture parameters, cylindrical averages in spherical coordinates, and visualization of the height reduction. This investigation was concluded by benchmarking the obtained texture parameters to values obtained from international peer-reviewed journals. Secondly, we have shown how XCHANTO could be useful for researchers. This included using texture parameters to describe surface growth with a temporal resolution and compare in between larger datasets. The quality of XCHANTOs output is dependent on the input CT data. Therefore, for optimal usage of XCHANTO, it will require an experienced operator to acquire and segment high-quality data. When data is acquired, XCHANTO offers a simple way of sophisticated analysis.