Ionic micro-emulsion assisted catalytic upgrading of heavy hydrocarbons at reservoir temperature: Effect of upgrading on rheology

Abstract

Background

Growing demand for energy and reduction of conventional or light hydrocarbon resources leads researchers and companies to discover economic and feasible methods for production of heavy hydrocarbons with different process specially hydrocarbon upgrading.

Methods

In this work, novel nickel and tin ionic water in oil (W/O) micro-emulsion catalysts are synthesized and used for in-situ upgrading reactions of heavy hydrocarbons. The best catalyst synthesis procedure based on the stability of W/O micro-emulsion was introduced. Rheology, composition, and sulfur content of upgraded samples were considered as the indication of reactions. Catalytic performance and activity of Ni and Sn in the static condition in the temperature range of 50–80 °C (reservoir temperature) and upgrading time up to 40 h were evaluated using a batch upgrading setup. Fourier transform infrared spectroscopy (FTIR), viscosity measurement, micro-emulsion size distribution, and stability analysis of micro-emulsion techniques were used for the characterization of upgraded samples and micro-emulsion catalysts. Finally, reservoir condition and operation condition equations were developed for the first time and results of various researches were compared as the performance evaluation method for the first time.

Significant finding

Experimental results reveal that not only prepared micro-emulsions at 50 °C (40 µm) is smaller than prepared ones at 25 °C, but also, they are more stable. It was found that hydrocarbon samples without micro-emulsion were not upgraded at 80 °C and the effect of thermal cracking in this reaction condition can be neglected. In addition, 68.38 % and 23.19 % viscosity reduction were observed for the 40 h upgrading of Ni micro-emulsion and Sn micro-emulsion at 80 °C, respectively. Also, the aromatic index based on FTIR analysis reveals that Sn catalyst illustrates lower severity in aromatic reduction from hydrocarbon samples than Ni micro-emulsion. Therefore, both viscosity and composition analysis confirm the superiority of Ni micro-emulsion catalyst for decreasing heavy molecules of samples such as double C=C ring bonds. On the other hand, the sulfur content index for the hydrocarbon samples, upgraded sample with Sn micro emulsion, and Ni micro-emulsion are 0.9463, 1.4657, and 1.3281, respectively. Thus, although Ni micro-emulsion shows better viscosity reduction performance, Sn micro emulsion has better performance in decreasing sulfur content. Finally, performance of these micro-emulsion catalysts was compared with other catalysts reported in the literature. Low cost and accessibility of these two metals provide a wide application for them in-situ upgrading reactions.