Boc, Inc.

The Boc Group, Inc.

Boc International Limited

The British Oxygen Company Limited

Kenneth C Smith

Michael E Garrett

John W Armond

David A Webber

Devasihamani J Sebastian

A compressed gas mixture, for example air, is passed through one of beds 12 and 14 of adsorbent that selectively adsorbs oxygen from the air. Unadsorbed nitrogen-enriched gas flows into a buffer vessel 28, from which product gas is withdrawn through pipeline 30. While one of the beds 12 and 14 is adsorbing oxygen for air the other is being regenerated, and during this period the communication between the beds is denied. At the end of a chosen period of time the beds are placed in communication with one another by opening valves 54 and 56. Then the bed that was previously being regenerated is placed in communication with the source of compressed air and the other bed regenerated. The period of intercommunication between the beds lasts for as long as it takes the volume of product gas as measured by an integrating flow meter 31 from the start of the preceding adsorption step to reach a chosen value. The apparatus is able to supply nitrogen of a chosen purity at a variable flow rate.

Process and apparatus for separation of a gaseous mixture

A fluid supply system includes a pressure-swing adsorption plant e.g. for supplying oxygen-rich gas to an activated sludge reactor in a sewage works. The product gas from the plant is supplied to the utilization apparatus by a compressor at a rate dependent on the demand for the gas, while waste gas is desorbed from the plant by a vacuum pump. When using the plant to separate oxygen from an air feedstock the major proportion of the power consumed by the plant is represented by the vacuum pump, which has to impell substantially greater volumes of gas than the product compressor. To economize on the power consumed by the plant, the rate of delivery of the vacuum pump is controlled by means sensitive to the demand of the utilization apparatus for product gas, so that a reduction in the demand from the product compressor leads to a reduction in the power consumption of the vacuum pump.

Fluid supply system including a pressure-swing adsorption plant

Oxygen containing gas is dissolved in sewage passing to, or through, a sewer during periods when sewage is being pumped therethrough. A stream of the sewage is withdrawn during periods when sewage is being held in the sewer. This stream is passed through a conduit so as to promote in such a stream dissolution of oxygen-containing gas introduced into, or entrained in, the stream. The stream is then returned to the sewer. By this means a chosen concentration of dissolved oxygen may be maintained in the volume of sewage between the points of withdrawal and return of the stream.

Sewage treatment

An air separation process using pressure swing adsorption techniques, for providing high purity oxygen. Two sections are employed one comprising beds of molecular sieve carbon and the other comprising beds of zeolite molecular sieve. Air is fed to a first of the sections which provides an oxygen-rich gas stream as feedstock for the next section where further enrichment takes place. The zeolite sieve section serves to effect a separation as between oxygen and nitrogen while the carbon sieve section serves to effect a separation as between oxygen and argon and the processes performed at each section are integrated in such a manner as to minimize power consumption and make use of gas recycled from the second section to the first in addition to the flow of gas from the first section to the second.

Gas separation

The invention relates to a system for treating liquid such as aqueous liquor with a gas that is sparingly soluble therein by introducing the gas into a pressurized stream of the liquid at a sufficient rate to dissolve some of the gas in the stream and additionally to form finely dispersed bubbles of undissolved gas which are carried within the stream. The velocity of the stream is sufficiently high to ensure that the bubbles do not combine to form a discrete vapor phase. The stream is introduced into a volume of the liquid under turbulent conditions so that the bubbles of undissolved gas are broken into even finer bubbles which either dissolve or are consumed in the liquid volume.

Treatment of liquid

A process for treating aqueous waste material having a biochemical oxygen demand, which process comprises passing the aqueous waste material along an elongate treatment tank or other elongate container for containing a volume of such material, having a transverse support structure or structures extending along the length of the tank or container and supporting aerobic micro-organisms, and dissolving an oxygenating gas in aqueous waste material at a plurality of positions spaced along the tank.

Treatment of waste water

The invention provides a method of, and apparatus for, treating sewage flowing through a sewer, wherein an oxygenating gas is introduced under pressure into the sewage and is dissolved therein and the thus oxygenated sewage is contact with a matrix of solid material carrying micro-organisms effective to reduce the Biochemical Oxygen Demand of the sewage, the matrix extending across a region inside the sewer. The treatment may be performed in a gravity sewer or in a rising or pumping sewer.

Treatment of sewage

An oxygenation system for promoting the activity of microorganisms supported on a filter bed, by introducing an oxygenated liquid stream into contact with the microorganisms.

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Roydon, United Kingdom

Kenneth C Smith