Final Report Summary - MINSC (Mineral Scale formation: from the atomic to the field scale)
MINSC has trained a new generation of fellows on nucleation and growth of mineral systems through this collaborative research program. The goal of this training was to address the problem of scale precipitation which causes pipe clogging, reduction in flow efficiency and elevated costs in pipe maintenance in oil, gas and energy industries. The systems investigated during the course of the project were representative of the most common scale formation minerals in the industry, i.e. gypsum, barium sulphate, calcite, magnesite, dolomite and silica. MINSC studied these systems in their pure state and in the presence of potential inhibitors, both in solution and on surfaces to represent pipe walls. Research work was divided into molecular, macroscopic and field study areas that were developed with eleven individual research projects.
At the molecular level, we achieved our goal of quantifying the nucleation and growth of various phases, the effects of inhibitors and associated surface mechanisms by studying the formation of the first solid precipitate and its subsequent growth in solution state and on surfaces. These investigations were performed using technologies capable of obtaining information on the atomic and molecular level of the first scale structures that formed.
For example during the study of sulfate scale (i.e. gypsum or barite) new insights were gained. For gypsum (project of ESR Taher Rabizadeh), it was discovered that using magnesium and polyepoxysuccinic acid effectively delayed the formation of gypsum and acted as good inhibitors. This was expressed in the fact that these inhibitors influenced the morphologies of the formed gypsum (i.e. from nanorods to plateles) and this has also a major effect on the way and mode the scaling process progressed. Furthermore, a model for gypsum formation at the molecular scale, based on high resolution synchrotron data was recently published by ER Tomasz Stawski (Tomasz M. Stawski, Alexander E.S. van Driessche, Mercedes Ossorio, Juan Diego Rodriguez-Blanco, Rogier Besselink and Liane G. Benning (2016) Formation of calcium sulfate through te aggregation of sub-3 nanometer primary species Nature Communications 7/11177 doi: 10.1038/ncomms11177) and was accompanied by a press release (http://www.eag.eu.com/about/media/how-gypsum-forms/) that was picked up and published by many international news outlets (e.g. EurekAlert and Science Daily, https://nature.altmetric.com/details/6421562/news). Likewise, investigations into the effect of a commercial copolymer (maleic acid/allyl sulfonic acid copolymer, used in the oil industry) on barite formation revealed that the adsorption of the copolymer on barite (001) surfaces almost completely blocked the formation of barite scale and dramatically reduced the size of the particles and yielding barite nanoparticles with different morphologies (work of ESR Christina Ruiz-Agudo).
For calcite scale formation, we studied the influence of sodium aspartame and glycine and demonstrated that the original morphologies changed (e.g. serrated edges or roughened shapes) in the presence of these inhibitors. Aspartame was revealed to be far more effective than glycine. We deduced that the functional carboxylic conformation of aspartame played a crucial role in these morphological changes. Advances were made in understanding the prevalence of different polymorphs depending on the saturation index and induction times that trigger the formation of calcite phases (e.g. calcite dominance over vaterite). Organic additives (e.g. aspartic acid) greatly affected the induction time for phase formation, type of polymorph, growth rate, and stabilising intermediate phases (e.g. vaterite). This work by ESR Giulia Montanari is currently under review with a high impact peer reviewed international journal (G. Montanari, L. Z. Lakshtanov, D. J. Tobler, K. N. Dalby, N. Bovet and S. L. S. Stipp (2016) The effect of aspartic acid and glycine on calcite growth, Crystal Growth & Design) Regarding silica scale, we obtained unreported details of the polymerisation and aggregation of silica and tested potential inhibitors for silica. However, any of the candidates inhibited its formation and instead, our findings indicate that it would be beneficial to the formation of silica to limit corrosion in pipes and learnt that silica fractionation is an useful tool to monitor re-precipitation of silica minerals in carbon injection sites. We studied these processes in detail at the Hellisheiði geothermal power station in south-west (Iceland). This work by ESR Daniela Meier is under review with Langmuir since March 2016.
At the macroscale level, we accomplished our initial objective of studying bulk scale mineral formation and kinetics through different approaches like hydrodynamics and fluid flow studies, the effects of CO2 injection in porous media, the development of robust computational models and transport, using flow through reactors, studying mineral formation at different temperatures and pressures, and the use of geochemical databases for precipitation at high salinity conditions. We investigated the growth kinetics of magnesite and dolomite under hydrothermal conditions and the influence of inducing carbonate precipitation. We confirmed the effects of supersaturation Ca/Mg ratios at high temperatures, cation dehydration at high temperatures that induce carbonate precipitation affecting the kinetics of magnesite formation and the incorporation of Ca in the magnesite structure under hydrothermal conditions. This is the work of ESR Nik Berninger (who submitted his PhD thesis on April 10th 2016 and will defend soon). His first publication (Berninger, U.N. ey al (2014) The experimental determination of hydromagnesite precipitation rates at 22.5–75°C Mineralogical Magazine, Nov 2014, v. 78, p. 1405-1416 doi:10.1180/minmag.2014.078.6.07) helped him develop the second part of his PhD.
We also completed our investigations into the effects of CO2 injection in porous media and elucidated three pH dependent stages of the process for which this occurs: (1) leaching and secondary mineral formation, (2) leaching and secondary growth and (3) dissolution of secondary minerals.
This work has given significant insight into mass transfer in fluid-rock interfaces on the macroscopic scale of these processes and has elucidated the kinetics of mineralisation. We obtained physical and mechanical aspects of fluid flow and surface growth during scale formation using theoretical and computational studies. In relation to this, we simulated precipitation under the influence of fluid flow by studying the growth and interaction between discrete precipitates along a reactive wall in a non-laminar channel flow and showed that the competition between advective transport, diffusion, and mixing strongly influences the downstream precipitates morphology and the typical correlation length between different precipitates (this was the project of .ESR Christopher Hawkings at the University of Oslo (defended his PhD already and publishing several papers; see MINSC publication website for details). His final manuscript which is in review with the Journal Langmuir furthermore is also a result of a cross-academic collaboration between him and ESR Daniela Meier (at Leeds) and combined molecular modeling with field observations and analyses of silica scale formation in Iceland. Another project addressed the use of 3D tomography to study porosity, pore connectivity and pore distribution in scale formation and proposed a new method for data processing in order to obtain more reliable information (work of ESR Diwaker Jha based at University of Copenhagen and published in 2014; Jha, Diwaker; Sørensen, Henning Osholm; Dobberschütz, Sören; Feidenhans'l, Robert Krarup; Stipp, Susan Louise Svane (2014). Adaptive center determination for effective suppression of ring artifacts in tomography images. Applied Physics Letters, Vol. 105, 143107). In addition, we investigated the use of thermodynamic data with Pitzer calculations to predict the scale formation of systems like barite at high-salinity conditions typical in oil industry. The results of this work were published by ESR Biyun Zhen Wu, based at industrial partner, Maersk (B. Y. Zhen-Wu, K. Dideriksen, D. A. Belova, P. J. Raahauge, S. L. S. Stipp (2014) A comparison of standard thermodynamic properties and solubility data for baryte, Ba2+(aq) and SO42-(aq), Mineralogical Magazine, v. 78, i. 6, p. 1505-1515, doi:10.1180/minmag.2014.078.6.1).
At the field level, we developed a field work instrument for silica colorimetric analysis and tested it at the Hellisheidi Power Plant (Iceland). Also, in a separate study we demonstrated that the use of hydrological tracers to monitor pore-volume changes (i.e. precipitation) is not appropriate for all environmental conditions as they react with the media. This work by ESR Fernando Berro Jimenez based at industrial partner West Systems was published in 2014 (Fernando Berro, Matteo Lelli, Ilaria Minardi, Giorgio Virgili (2014) A procedure for eliminating sulfide interference on silica colorimetric analysis Mineralogical Magazine, v. 78, i. 6, p. 1417-1422, DOI: 10.1180/minmag.2014.078.6.08) and was the basis of the prototype deliverable which the ESR subsequently completed as part of his PhD.
Our current industrial partners (i.e. Maersk Oil and Gas, Reykjavik Energy) have already benefited from the knowledge provided by the MINSC project in understanding problems of mineral scale formation in sections of their pipeline industrial processes and introducing new practices to improve efficiency that have a positive impact in production costs and to extend the lifetime of the infrastructure. Similar industrial processes (e.g. food processing, paper-making, chemical manufacturing, cement operations, etc.) will benefit from the final results achieved by the MINSC project and help them to develop corrective measures (e.g. using the tested inhibitors) that will prolong the production pipes, improve efficiency, reduce costs and avoid the use of inadequate chemicals detrimental to the environment.
The MINSC network has provided knowledge and cutting-edge training to young researches who have become experts in a topic relevant for the industry. They now understand the fundamentals and mechanisms of mineral scale formation and are able to apply this knowledge to different conditions and environments. Thus, this project has contributed positively towards the career of young researches and delivered well trained researchers to the European employment market, which will highly benefit from having people trained in these new interdisciplinary and inter-sectoral skills that will help tackling and solving problems of importance for the European economy.
In conclusion, MINSC has fully met the originally defined objectives listed in the original annex. The success of the project is evidenced by numerous publications produced by the fellows and by the the fact that many fellows have already found post-doctoral positions thanks to their work as researchers on the MINSC project. Marie Curie training networks are a valuable asset to the European Union and represent great hope for the future of science in Europe.