Abstract: Oxygen or an oxygen-rich gas is used in the production of terephthalic acid in a reaction system that mitigates the flammability hazards associated therewith. Lower reactant and solvent consumption is achieved, with lower production of unwanted by-products, lower gas handling costs and lower environmental impact concerns than with conventional air based terephthalic acid production.

Abstract: In systems in which air is introduced into a liquid as a source of oxygen, additional oxygen added independent of the feed air enhances the oxygen content of the liquid source significantly than if the same amount of additional oxygen were combined with the feed air.

Abstract: Textile bleaching operations are enhanced by passing the cloth being treated alternately between an aqueous hydrogen peroxide solution and an oxygen-containing head space.

Abstract: Bioremediation or other liquid waste biotreatment operations are enhanced by the use of turbulence promoters to create turbulent flow conditions in an oxygen/liquid waste dispersion prior to passage in an improved gas/liquid distribution system for passage through eductors into a lagoon or other holding source of the liquid waste being treated.

Abstract: A high efficiency gas dissolution system is used to dissolve gas in a portion of a body of liquid, improving gas utilization and reducing associated energy requirements. A portion of the body of liquid is recirculated through a mechanical, in-line gas dissolution device wherein a secondary feed gas is dissolved in the liquid.

Abstract: A gas-liquid mixing process and apparatus employing two or more stacked impeller-draft tube assemblies adapted to enable effective gas ingestion into a recirculating body of liquid by vortex development to be continued upon an appreciable variation in liquid level during the course of the mixing operation.

Abstract: A gas-liquid mixing vessel utilizes an axial flow, down-pumping impeller in a draft tube to create vortex development so as to draw gas from the overhead in a body of recirculating liquid. A surge tank is used to accommodate volume changes in the vessel, and a liquid level control feature, in which the gas phase pressures in the mixing vessel and the surge tank are adjusted, is used to maintain the liquid level in the mixing vessel at a desired level for proper vortex development.

Abstract: The pump energy requirements for the dissolving of a gas in a liquid are significantly reduced by injecting gas bubbles into a stream of said liquid at a relatively low pressure, utilizing a pressure head of liquid to increase the solubility of the gas in the liquid, and employing liquid stream velocities and gas-liquid contractor diameters and lengths, gas dispersion means and residence times such as to obtain a desired level of gas concentration in the liquid.

Abstract: A gas-liquid mixing process and apparatus having a vessel with an axial flow down-pumping impeller in a draft tube has gas ingestion tubes extending into a body of liquid from a hollow portion of the impeller shaft or other fluid communication means with the overhead gas in the vessel. Upon gas-liquid mixing at liquid levels that interfere with vortex development by the impeller, gas is drawn from the overhead through the ingestion tubes into the body of liquid.

Abstract: A feed gas stream is introduced directly into a recirculating liquid stream so as to facilitate formation and maintenance of gas bubbles in a dispersed form in a recirculating gas bubble-liquid mixture. By the maintaining of a gas-liquid interface and overhead gas phase in conjunction with a quiescent zone of liquid apart from the portion of liquid in which said mixture is maintained in a recirculating flow condition, the loss of appreciable amounts of gas to the overhead gas phase is avoided.

Abstract: Gas dispersion in a liquid is enhanced by combining the gas and liquid in close proximity to a venturi or other flow constriction means used to create supersonic flow velocities and subsequent deacceleration to sub-sonic velocity. When a venturi is employed, the gas-liquid mixing occurs in the converging portion of the venturi or upstream but in close proximity to said venturi. Turbulent flow conditions upstream of the venturi or other flow constriction means adequate to disperse the gas uniformly in the liquid are not required and, surprisingly, the gas and liquid need not be uniformly dispersed prior to acceleration to supersonic velocity.

Abstract: In a process for the uniform distribution of a two phase gas/liquid or liquid/liquid mixture comprising delivering a first stream of said mixture to a point, and dividing the first stream at the point into at least two streams, the improvement comprising creating a turbulent environment in the first stream just prior to the point at which the first stream is divided into at least two streams.

Abstract: In a process for mixing a gas and a liquid in an apparatus having an axial flow down-pumping impeller located in a draft tube and preceded by a first baffle wherein a vortex and turbulence are created and gas is drawn into the vortex, the improvement comprising providing liquid velocity of at least one foot per second, increasing the turbulence, providing a second baffle below the impeller, and a high shear zone between impeller and the second baffle.

Abstract: In a process for mixing a gas and a liquid in an apparatus having an axial flow down-pumping impeller located in a draft tube and preceded by a first baffle wherein a vortex and turbulence are created and gas is drawn into the vortex, the improvement comprising providing liquid velocity of at least one foot per second, increasing the turbulence, providing a second baffle below the impeller, and a high shear zone between impeller and the second baffle.