Application of geothermal energy for heating and fresh water production in a brackish water greenhouse desalination unit: A case study from Algeria

The aim of this paper was to outline a proposed a new brackish water greenhouse desalination unit powered by geothermal energy for the development of arid and relatively cold regions, using Algeria as a case study. Countries which have abundant sea/brackish water resources and good geothermal conditions are ideal candidates for producing fresh water from sea/brackish water. The establishment of human habitats in these arid areas strongly depends on availability of fresh water. The main advantage of using geothermal energy to power brackish water greenhouse desalination units is that this renewable energy source can provide power 24 h a day. This resource is generally invariant with less intermittence problems compared to other renewable resources such as solar or wind energy. Geothermal resources can both be used to heat the greenhouses and to provide fresh water needed for irrigation of the crops cultivated inside the greenhouses. A review of the geothermal potential in the case study country is also outlined.Brackish water greenhouse desalination Geothermal energy Algeria Heating Renewable energy

Thermal gelation of partially hydrolysed polyacrylamide/polyethylenimine mixtures using design of experiments approach

International audiencePolyethylenimine crosslinked polymer gels are gaining a huge interest in conformance control applications in oilfields. They are used to reduce the production of undesirable fluids (water & gas) by blocking the fractures that connect injection and production wells. In this paper, a statistical analysis on the thermal gelation of well characterized reactants namely partially hydrolysed polyacrylamide (PHPA) (Mw = 5.1 million Daltons and hydrolysis degree = 6%) and polyethylenimine (PEI) (Mw = 19.2 kilo Daltons and branching degree = 59%), was conducted using response surface methodology (RSM). A four factor doehlert matrix was employed in designing the experiments and evaluating the gelation time as function of salinity (0–8 g/L NaCl), polymer (PHPA) and crosslinker (PEI) concentrations, temperature (70 °C–90 °C) and their corresponding combinations. As a result, the gelation time was found to strongly vary with salinity, temperature and PHPA concentration following a nonlinear mathematical model. The analysis of variance (ANOVA) of this model revealed its significance in a 95% confidence level against experimental data. In a second part, an experimental investigation was carried out to understand the interaction between PHPA and PEI. To do so, the viscosity variations of analogue mixtures prepared with low molecular weight (Mw) polymers, such as polyacrylamide (PAM) and polyacrylic acid (PAA), were monitored using capillary viscometry at different conditions of temperature, pH and reaction time. The PAM/PEI mixtures showed a remarkable viscosity increase at typical pH of around 10 when cured at 80 °C. While, the PAA/PEI mixtures underwent precipitation at pH of around 6 revealing the strong interaction between PAA and PEI at this condition

Structure–property relationships of the thermal gelation of partially hydrolyzed polyacrylamide/polyethylenimine mixtures in a semidilute regime

International audienceIn this work, the structure–property relationships of the thermal gelation of partially hydrolyzed polyacrylamide (PHPA) and polyethylenimine (PEI) mixtures were investigated under realistic conditions of temperature (80 °C) and salinity (total dissolved solids = 3.4 g/l) of the Algerian reservoir (Tin Fouyé Tabankort) prior to a conformance control application. The reactants were characterized with regard to their hydrolysis degree or branching degree using 13C-nuclear magnetic resonance, and viscosity–average molecular weights (M¯v) were estimated using the Mark–Houwink equation and intrinsic viscosities measurements. The polymers had molecular weights that varied from 5 to 10 × 106 g/mol for PHPAs with initial hydrolysis degrees between 6 and 20 mol%, while the molecular weights of the PEI were between 2 and 67 × 104 g/mol with a constant branching degree of 57–59. Consequently, the effect of steady shear on the gelation time was investigated followed by the effect of reactant concentrations, the polymer and cross-linker molecular weights, the polymer’s hydrolysis degree, the temperature and the initial pH. All experiments were conducted in a semidilute concentration regime while maintaining practical initial gelant viscosities. As a result, the gelation time was found to decrease with reactant concentrations, molecular weights and temperature (Ea = 62 kJ/mol) and to increase with hydrolysis degree

Experimental design methodology as a tool to optimize the adsorption of new surfactant on the Algerian rock reservoir: cEOR applications

International audienceIn this research work, a new surfactant called surf EOR ASP 5100 used in the SWCTT (single well chemical tracer test) in the Algerian oilfield and sodium dodecyl sulfate (SDS) were used for static adsorption tests. The Algerian rock reservoir has been characterized by different techniques such as SEM, XRD, XRF, BET analysis. The equilibrium was successfully verified by Langmuir isotherm and second-order (R2gt; 95 % models for all concentrations and temperatures to predict the adsorption process. Furthermore, the adsorption process was found to be exothermic (ΔG∘lt; 0 . To quantify the minimal adsorbed quantity, a full factorial design of 23 (8 experiments) was applied to analyze the individual effects and interactions of operational parameters using variance analysis (ANOVA), desirability method and response surface methodology. The optimal conditions obtained are as follows: the Qe value was 2.3291mg/g for the SDS surfactant at a concentration of 200ppm and temperature of 25 ∘ C, and Qe was 3.894513mg/g for EOR ASP 5100 for the concentration of 200ppm and temperature of 80 ∘ C