Method for On-line Imaging of Mesophase Particles

Abstract

On-line detection of mesophase particles employs a laser diode light source to illuminate a target area with a pulsed laser linearly or circularly polarized probe beam. Analysis of images determines extent of presence the birefringent mesophase particles, which are precursors to coking in catalytic hydrocracking processes. The inherently polarized low-coherence, unfocused but sufficiently collimated, pulsed laser beam yield sharp imaging with high depth of field of very small mesophase particles that are present in a moving, dark reactor liquid environment.

Description

FIELD OF THE INVENTION[0001]The present invention generally relates to sensors and methods for detecting the presence of mesophase particles, which are precursors of coking, and more particularly to techniques of using an inherently polarized, unfocused but sufficiently collimated, pulsed laser beam illumination for on-line linear-polarized light imaging and circular-polarized light imaging of the mesophase particles.BACKGROUND OF THE INVENTION[0002]In heavy oil upgrading, heavier materials are converted to lighter fractions and most of the sulfur, nitrogen and metals must be removed. Heavy oils include materials such as petroleum crude oil, atmospheric tower bottoms products, vacuum tower bottoms products, heavy cycle oils, shale oils, coal derived liquids, crude oil residuum, topped crude oils and the heavy bituminous oils extracted from oil sands. Most residual oil feedstocks which are to be upgraded contain some level of asphaltenes which are typically understood to be heptane i...

AI Technical Summary

Benefits of technology

The patent text describes a method for accurately measuring the size and volume fraction of particles in a reactor liquid during hydrocracking. This is done using a special laser system that produces polarized light that is then cross-polarized to create a more accurate image. By adjusting the reactor conditions, the levels of these particles can be reduced. The use of a linearly polarized laser and a low coherence light source helps to overcome the speckle phenomenon that can make it difficult to detect these particles. The cross-polarizer imaging technique also allows for the "frozen" motion of the particles in the reactor, making the measurements less sensitive to vibrations.

Problems solved by technology

The formation of mesophase particles is typically monitored by labor-intensive laboratory analysis that entail several hours of delay to actual process events.

Images