Economic appraisal of Power-to-Liquid Fischer-Tropsch plants exploiting renewable electricity, green hydrogen, and CO2 from biogas in Europe

The present work analyses the techno-economic potential of Power-to-Liquid routes to synthesize Fischer-Tropsch paraffin waxes for the chemical sector. The Fischer-Tropsch production unit is supplied with hydrogen produced by electrolysis and CO2 from biogas upgrading. In the analysis, 17 preferential locations were identified in Germany and Italy, where a flow of 1 t/h of carbon dioxide was ensured. For each location, the available flow of CO2 and the capacity factors for both wind and solar PV were estimated. A metaheuristic-based approach was used to identify the cost-optimal process design of the proposed system. Accordingly, the sizes of the hydrogen storage, electrolyzer, PV field, and wind park were evaluated. The analysis studied the possibility of having different percentage of electricity coming from the electric grid, going from full-grid to full-RES configurations. Results show that the lowest cost of Fischer-Tropsch wax production is 6.00 €/kg at full-grid operation and 25.1 €/kg for the full-RES solution. Wind availability has a key role in lowering the wax cost.

Uncovering Mysteries of Waxphaltenes: Meticulous Experimental Studies of Field and Lab Deposits Unveil Nature of Wax-Asphaltene Intermolecular Interactions

In recent years, the utilization of modern sampling tools provided access to the field deposits from several offshore and onshore wells producing asphaltenic crudes. Compositional analysis of field deposits revealed the presence of asphaltenes and wax as major fractions, while system conditions traditionally implied precipitation and deposition of asphaltenes only. Most of the previous studies on organic deposition have been conducted with the key assumption that aggregation and precipitation of wax and asphaltene occur independently. A few researchers investigated the solubility parameter's alteration, but they did not incorporate waxes found in the oilfield deposits. This study aims to investigate the nature of "waxphaltenes"; from intermolecular interactions between asphaltenes and wax in samples collected from fields and made in the laboratory. Asphaltenes samples were extracted and fully characterized by proton nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR). Paraffin waxes were identified using gas chromatography (GC), differential scanning calorimetry (DSC), NMR, and FTIR. Precipitation tests of asphaltenes with n-heptane at high temperature were performed both in the presence and absence of wax; GC, NMR and FTIR techniques evaluated the precipitates and the material dispersed in solution. It was found that asphaltenes co-precipitated with waxes even at higher temperatures than the normal wax appearance temperature (WAT) of the crude oil or the model solutions and that long and medium size paraffin waxes had higher tendencies to coprecipitate with asphaltenes than either short chain or very long chain paraffin hydrocarbons. The results also indicated that the amount of wax that co-precipitates with asphaltenes was more related to asphaltene structure but is independent of the asphaltenes or wax content. Heteroatoms played an important role in the interactions between wax and asphaltenes during precipitation and separation.

Melting of Paraffin Waxes Embedded in a Porous Matrix Made by Additive Manufacturing

The recent advances in additive manufacturing technology have widened the choice of materials that can be printed, opening new frontiers in the field of heat transfer devices. This paper explores the use of a solid porous matrix in which paraffin waxes, having different melting temperatures (42, 55, and 64 °C), were embedded. The solid matrix is made by additive manufacturing. The parent cell of the porous matrix occupies the volume of a cube with an edge of 5 mm. The entire 3D printed matrix has a square base with an edge of 100 mm, and it has a height of 20 mm. The solid matrix was printed between two plates, each one with a thickness of 10 mm, where thermocouples were inserted, and it was tested in an upright position, laterally heated applying three different heat fluxes (10, 15, and 20 kW m−2). The experimental results are given in terms of the temperature of the heated side, as well as of the phase change material, during the heating process. The temperature reached by the heated side and the time needed to completely melt the paraffin waxes are compared at the different working conditions. Furthermore, the thermal conductivities and diffusivities of the three paraffins and of the parent material of the porous matrix were experimentally evaluated.

Paraffin Wax-Based Thermal Composites

Paraffin waxes are organic phase change materials possessing a great potential to store and release thermal energy. The reversible solid–liquid phase change phenomenon is the under-lying mechanism enabling the paraffin waxes as robust thermal reservoirs based on inherently high latent heat (i.e., ~200–250 J/g). However, the main drawback of paraffin waxes is their inability to expedite the phase change process owing to low thermal conductivity (i.e., ~0.19–0.35 Wm−1 K−1). This drawback has long been documented as a technological challenge of paraffin waxes especially for temperature-control applications where faster thermal storage/release is necessitated, encompassing thermal management of batteries, thermoelectric modules and photovoltaic panels. Besides, sustaining the solid-like form of paraffin waxes (shape-stability) is also recommended to avoid the liquid drainage threats for crucial applications, like thermal management of buildings and fabrics. These objectives can be met by developing the paraffin wax-based thermal composites (PWTCs) with help of various thermal reinforcements. However, PWTCs also encounter severe challenges, probably due to lack of design standards. This chapter attempts presenting the recent advances and major bottlenecks of PWTCs, as well as proposing the design standards for optimal PWTCs. Also, the fundamental classification of phase change phenomenon, paraffin waxes and potential thermal reinforcements is thoroughly included.

Enhancement of Separated Ultra Pure n-paraffin as Phase Change Materials (PCM) by W-Fe Bimetallic Oxides

Objective:: Six ultra pure Paraffin Waxes (PW) were successfully fractionated at 35°, 30°, 25°, 20°, 15° and 10°C. The bimetallic oxide (Ferberite) was successfully synthesized by Microwave assisted method. Methods: Enhanced Phase Change Materials (PCMs) were designed by loading W/Fe bimetallic oxides in the ultra pure PW matrix at 1, 2, 3, 4 and 5 wt. %. paraffin wax, W/Fe bimetallic oxide and the resultant composite blends were characterized by X-ray Diffraction (XRD), Gas Chromatography (GC), Deferential Scanning Calorimetry (DSC), Polarized Optical Microscope (POM), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). In addition to testing the thermal conductivity of the designed blends. According to SEM, DSC and POM data, the prepared nanocomposite was homogeneously dispersed into the selected PW matrix. Results: Data revealed that thermal conductivity of the designed composite increases with increasing the loading ratio of W-Fe bimetallic oxides. The total latent heat storage ΔHT of the initial sample was improved from 295.91 J/g to 311.48 J/g at 5 wt. % loading percent. Conclusion:: Thermal conductivity was improved from 8.54 to 21.77 W/m2k with increasing up to 255% in comparison with pure paraffin wax.