Marco Maschietti

The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water

The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370°C and its effect on the process was investigated in a continuous flow (1kg/h). The yields of water-soluble organics (WSO), bio-oil and char (dry lignin basis) were in the ranges of 5-11%, 69-87% and 16-22%, respectively. The bio-oil, being partially deoxygenated, exhibited higher carbon content and heat value, but lower sulphur content than lignin. The main 1-ring aromatics (in WSO and diethylether-soluble bio-oil) were anisoles, alkylphenols, catechols and guaiacols. The results show that increasing temperature increases the yield of 1-ring aromatics remarkably, while it increases the formation of char moderately. An increase in the yields of anisoles, alkylphenols and catechols, together with a decrease in the yield of guaiacols, was also observed.

A Triethylene Glycol–Water System: A Study of the TEG Regeneration Processes in Natural Gas Dehydration Plants

Abstract Natural gas pipeline transportation requires very low water content in the gas stream in order to avoid condensation or hydrate formation. To reach this goal, when triethylene glycol is used to dehydrate natural gas, after the absorption step, triethylene glycol must be regenerated to levels substantially above 98.5–99.0% by weight available from atmospheric distillation of glycol-water mixtures. In order to regenerate triethylene glycol to higher purity levels, some of the methods used require a stripping gas, a solvent, or to perform the distillation under vacuum. Another method to perform a further dehydration of triethylene glycol is the use of a water exhauster, known as Coldfinger, where the vapor in equilibrium with the liquid to be dehydrated is continuously condensed and removed. In the first part of this work, measurements of boiling temperatures are reported for binary mixtures of triethylene glycol and water at pressures of 50, 100, 200, and 400 mmHg. The experimental data obtained were correlated by employing the NRTL model, with temperature-dependent parameters, to express activities in the liquid phase. The fitted NRTL parameters were then used in the Hysys process simulator to perform a process simulation of a natural gas dehydration plant, provided both with a Coldfinger water exhauster and a conventional stripping column for triethylene glycol regeneration.

Net proton charge of β- and κ-casein in concentrated aqueous electrolyte solutions

Abstract Titration experiments have been carried out in order to measure the net proton charge of β- and κ-casein in NaCl solutions at 0.1 M and 1 M salt concentrations, at 4 °C, in the pH range between 5.5 and 10.5. Experimental data are compared with model values calculated through pKas of titrable groups neglecting the electrostatic perturbation term (ΔpKa) in order to evaluate the magnitude of the error caused by this approximation and to delimit its effectiveness. At both ionic strengths, the agreement is good for κ-casein in the pH range [5.5, 9.5], while errors of up to 2 charges are observed for β-casein in the same range. These deviations are likely to be caused by strong electrostatic effects induced by the high density of negative charges of β-casein 1–21 peptide. In order to account for these electrostatic effects, the net proton charge on this peptide is evaluated through a model based on the counterion condensation theory developed for the titration of polyelectrolytes with different types of ionizable groups.

Natural gas dehydration: A triethylene glycol – water system analysis

Abstract Absorption by means of triethylene glycol is one of the most popular methods for natural gas dehydration. In spite of this popularity, thermodynamic modeling of the system TEG-water is still rather inaccurate, especially with regard to systems at high temperature and high TEG concentration, which are typical conditions in the glycol regeneration unit. Available experimental data were selected and correlated by means of a thermodynamic model based on the Peng-Robinson equation of state. Obtained results show that the model provides a good representation of experimental data and leads to a reliable prevision on typical plant data. Because of its accuracy and simplicity, the proposed model is a valuable tool for the design of natural gas dehydration processes.

Time-Temperature Indicators for Perishable Products

Time-Temperature Indicators (TTIs) are small devices which provide easy-to-read, visual information regarding the thermal history of perishable products. They are typically designed as small labels suitable for application onto the packaging of single product items. TTI labels are inexpensive, especially when compared to temperature electronic recorders, which are intended to monitor warehouses or means of transportation, rather than monitor single product items. Current and potential fields of application comprise food, pharmaceutical, biomedical and floral products. In the present paper the functioning principles of several TTIs are analysed with regard both to theoretical and practical aspects. There are various basic principles involved in the design of TTIs ranging from chemical reactions to physical phenomena. These principles include solid phase chemical reactions, biochemical reactions, biological systems, the transition of colour indicators in reacting phases, molecular diffusion, motion of viscous liquids, melting or glass transition of solids, gas permeation, osmosis, and nanoparticles. A selection of the most relevant patents was made according to the following criteria: the commercial success of the TTIs or their potential commercial viability, the recentness of the publications, and the originality of the fundamental principles of the inventions.

Preliminary evaluation of the impact of modified injection water composition on the oil/water separation in produced water treatment facilities

The effect of the electrolyte composition of produced water in oil & gas production facilities was investigated by developing a laboratory scale oil/water separation setup and a related procedure, coupled with an analytical method based on the OSPAR reference method for oil-in-water measurement. The experimental plan was aimed at investigating the effect of the ionic strength, for a given electrolyte, and of different electrolytes, for a given ionic strength, on the separation of oil droplets from the aqueous phase. The oil-inwater concentration was reported against settling time, for a number of different ionic compositions. It was observed that increasing the ionic strength increases the separation efficiency, with more pronounced differences for settling times closer to those typical for the three phase separators in use in the field. For example, for a settling time of 5 min the increase in oil-in-water concentration caused by reducing the ionic strength from seawater level down to zero resulted in a reduction of the separation efficiency up to 37%. This result clearly shows the importance of the electrolytes in the kinetics of oil/water separation, for typical residence times in use in offshore production facilities. Changing the type of electrolyte for a given ionic strength gave results that are not conclusive and worth investigating further. In addition to the separation kinetics, the interfacial tension (IFT) between the crude oil and the different aqueous electrolyte solutions was measured. Only slight differences in the IFT were observed, thus suggesting that other parameters (e.g. ζpotential) are expected to be more relevant in explaining the observed differences in the separation kinetics. The developed experimental method for measuring the separation kinetics proved reliable and can serve as a basis for further investigations aimed at comparing the separation rate of actual brines vs. modified brines, i.e. brines with the composition that can be expected as a consequence of the application of enhanced oil recovery methods, such as SMART water injection.