Deepak M. Kirpalani

Improving the efficiency of fluid cokers by altering two-phase feed characteristics

Abstract Fluid cokers are widely used in the petroleum industry but limited research has been reported for optimizing their feed injector systems. In the present work, the effect of variation in the two-phase flow, with respect to impact on atomization for the range of nominal commercial operating conditions for the feed system, was investigated. A commercial scale injector was assembled and air–water flow dynamics through the assembly was examined to understand the effect of small variation in the mass ratio of gas to liquid on injector operation. The air-to-liquid mass ratio (ALR) is typically used to correlate results for this type of water spray testing. In terms of droplet size and spray dispersion, the measured and observed effects for change in the type of flow were correlated with the resulting atomization efficiency. A full-scale test system was made of clear Plexiglas pipe to allow observation of the flow. Operating conditions for the tests were in the range of nominal commercial operation. Intermittent or slug flow and dispersed bubble (DB) flow regimes were observed in the transparent injector assembly for the range of conditions studied. In the present research, small changes in the gas flow rate through the spray injector system were demonstrated to alter the two-phase flow structure and subsequent atomization significantly. This change could be encountered in commercial operations where there is a malfunction such as a partially plugged nozzle. Experimental results from this work were applied to selecting optimal operating conditions for commercial operation. From this, criteria for droplet size and spray dispersion were selected for increased efficiency of coker operation. In general, dispersed bubble flow was determined to provide better atomization and dispersion of the spray and thereby potentially improve coker efficiency. Another aspect of this research was to develop a signal analysis method to analyze pulsation patterns measured for the two-phase flow passing through the injector feed system. This analysis allowed qualification of the two-phase flow type and was investigated as a tool for an on-line monitoring tool of the commercial spray injector system.

Process effluents and mine tailings: sources, effects and management and role of nanotechnology

Abstract Increasing population levels, growing economies, rapid urbanization and changes in consumption patterns have increased the demand for raw materials such as base and precious metals, leading to growing concerns regarding their availability and the global efficiency of the mine supply chain. Mine tailings, consisting of process effluents that are generated in a mineral processing plant, are generally transferred to tailings ponds/impoundments to meet environmental regulations and site-specific factors before discharge. Most mining activities induce an impact on their geochemical environment (e.g., water, groundwater) due to the presence of metal-rich tailing deposits. The need for a comprehensive framework for mine tailings management that promotes sustainable development is therefore becoming increasingly recognized by the mining industry. Therefore, for sustainable rehabilitation and disposal of mining waste, the sources and mechanisms of pollutant generation and their subsequent effect on environment and sustainable treatment methods are critical. This review includes information on different sources of mining waters and its effect on groundwater contamination and ecological effects. The review also encompasses a broad range of mine water treatment strategies available for innovative management of mining tailings with a specific emphasis on the role of nanoparticles in the management of mine waters.

An Apparatus for Automated Cross Flow Solute Permeation Characterization of Membranes

Abstract An apparatus is described for the automated characterization of ultrafiltration membranes using solute permeation in cross flow mode. The automated characterization approach described in this work lends itself well for the purpose of increased productivity and reducing operator fatigue/error. The operational, control, and data acquisition aspects of an automated membrane cross flow test unit, which are accomplished using LabVIEW 5.0™ are described. The interpretation of the flux and separation data is independent of the apparatus and depends on the filtration regime and various theoretical models available. The apparatus can be used for reverse osmosis, nanofiltration, or ultrafiltration experiments, with appropriate selection of test cells and pumps. Issued as NRCC No. 47871.