Prediction of temperature, pressure, density, velocity distribution in H‐T‐H‐P gas wells

Abstract

In this paper, we build a model of coupled differential equations concerning pressure, temperature density and velocity in H-T-H-P (High Temperature-High Pressure) gas wells according to the conservation of mass, momentum and energy. We present an algorithm-solving model by the fourth-order Runge-Kutta method. Basic data from the Dayi Well, 7100 m deep in China, are used for case history calculations and a sensitivity analysis is done for the model. Gas pressure, temperature, velocity and density along the depth of the well are plotted with different productions, different geothermal gradients and different thermal conductivities, intuitively reflecting gas flow law and the characteristics of heat transfer in formation. The results can provide a dynamic analysis of production for H-T-H-P gas wells.

Production of zwitterionic cellulose by citric acid and triethanolamine hydrochloride for various end uses

“…Acid dyeing (pH 3) was started at 40 °C; the temperature was raised to 98 °C for 25 min at a 23 °C/min rate, and we maintained the temperature for 35 min before decreased it to 60 °C for 15 min . In contrast, cationic dyeing (pH 8) was started at 25 °C; we raised the temperature to 98 °C for 73 min, maintained the temperature for 35 min, and then decreased it to 60 °C for 15 min . Moreover, the pHs of the dyeing bath were controlled at 2, 4, 6, 8, and 10 with HCl and NaOH to investigate the effect of pH on the dyeing processes.…”

“…The addition of cationic reagents minimize repulsion between the two anionic moieties . Furthermore, cationized and PCA‐treated cotton can produce other characteristics, such as antibacterial and zwitterionic properties . Because zwitterionic substrates are dipolar, having both negative and positive charges, they can react with acids as well as bases.…”

“…Therefore, these substrates can be applied in the purification of industrial wastewater and effluents. It was shown that efficiency of zwitterionic substrates in the removal contaminants was much better than that of cationized or hydrolyzed substrates . The removal of used dye from effluents is a critical process when one considers the stability and toxicity of dyes containing aromatic groups .…”

“…The removal of used dye from effluents is a critical process when one considers the stability and toxicity of dyes containing aromatic groups . These zwitterionic substrates can actively sorb both anionic and cationic compounds . Furthermore, zwitterionic cotton can generate different electrical properties at various pHs, and consequently, their applicability could be much broader than just the treatment of dyeing effluents.…”

Starch Derivatives Bearing Aromatic Sulfonated Functional Groups

“…Anionic starch derivatives have been used to remove cationic colorants from aqueous solutions as a low cost alternative adsorbent for wastewater treatment . Methylene blue (MB) is used as indication of the presence of sulfonated groups in starch derivatives.…”