Wet air oxidation: a review of process technologies and aspects in reactor design

Described are methods of cultivating autotrophic microorganisms, particularly microalgae or diatoms, in a bioreactor by entraining a culture of the microorganisms in a tenuous, gelated, thixotrophic carrier medium having nutrients therefor and moving the medium along a passage at a sufficiently slow speed to enable laminar flow which in cross section is closed and which has transparent walls through which the culture is irradiated to enable photosynthesis. The method includes effecting convective turnover of the culture and medium as they flow along the passage by differentially heating the medium laterally relative to the flow direction so as to produce a generally helical flow of the culture and medium. Also described are processing methods, both physical and chemical, performed underground e.g. in drillholes, to utilise decavitation energy under ambient elevated pressures, including processes to implement lysis of the micro-organisms, producing methanol, syngas synthesis, Haber ammonia synthesis, Fischer-Tropsch reactions, supercritical reactions, dimethyl ether synthesis, and nitric acid synthesis.

System for cultivation and processing of microorganisms, processing of products therefrom, and processing in drillhole reactors

Method/system of adding solid particles to inhibit or prevent plugging in a reactor at conditions such that the temperature and pressure are at least in the vicinity of supercritical conditions for water. Particles may be added in conjunction with a pH-adjusting material, thereby inhibiting plugging in the reactor caused by addition of the pH-adjusting material. Reactor pressure may be reduced by flowing the stream through a static restriction device.

Method and apparatus for reacting oxidizable matter with particles

In a high pressure and high temperature reaction system suitable for oxidative waste treatment, particularly a reaction system for supercritical water oxidation (SCWO), a method is disclosed for injecting a first fluid of a first temperature at a first flow rate into a second fluid of a second temperature at a second flow rate, mixing the first and the second fluids within a mixing length (115, 215), and wherein the first and second temperatures and the first and second flow rates are selected such that a temperature of the mixed fluids downstream of said mixing length (115, 215) is obtained, at which said first fluid being substantially non-corrosive.

A high pressure and high temperature reaction system

A method for treating a waste stream, the method including the steps of providing a waste stream that includes waste solids suspended in water, feeding the waste stream to the top of a hydraulic downdraft column, conducting the waste stream to the bottom of the hydraulic downdraft column, conducting the waste steam to a first reaction zone, introducing nitrogen-containing oxides into the first reaction zone so that the waste stream is contacted with the nitrogen-containing oxides, conducting the waste stream up a hydraulic updraft column into a second reaction zone, where the second reaction zone is configured to provide sufficient time so that a reaction between the nitrogen-containing oxides and waste solids can take place and substantially consume the nitrogen-containing oxides, introducing oxygen gas into the waste steam after the nitrogen-containing oxides are substantially consumed, thereby providing a second reactant that reacts with waste solids suspended within the stream, conducting the stream to the top of the hydraulic updraft column.

Method and apparatus for treating waste streams

In accordance with the present invention there is provided a reaction apparatus having an externalized heat exchange mechanism by which heat may be added to or withdrawn from a reactant mixture In one aspect, the present invention includes a cased well which extends approximately 5000 feet vertically into the earth in which at least one reaction vessel is suspended from a support plate at substantially ground level surface The reaction vessel comprises an outer closed-end tube in which an inner open-end tube is disposed in a concentric manner to define an annulus which is in flow communication with the bore of the inner tube Substantially parallel to the reaction vessel and also suspended from the ground level support plate, is a conduit which extends into the chamber defined by the well-casing In the method of the present invention, a mixture of reactants, preferably diluted municipal waste, is injected into the annulus of the reaction vessel to form a hydrostatic column which exerts substantial fluid pressure at a reaction zone in the lower part of the reaction vessel A heat-transfer medium, such as oil, is heated to an elevated temperature and then flowed through the conduit into the chamber where the hot heat-transfer medium envelopes the reaction vessel Heat is transferred from the heat-transfer medium to the reactant mixture through the wall of the outer closed-end tube In the case of an exothermic reaction, when the temperature of the reactants reaches a selected level, the reaction process gives off heat which is withdrawn by the heat exchange medium As the reactants form reaction products, the reaction products are flowed from the annulus through the bore of the inner tube back up to ground surface level

Asymmetric heat-exchange reaction apparatus for effecting chemical reactions

A process is disclosed for co-processing spent nitric acid wash water with organic or biological wastes under wet oxidation conditions whereby the nitrogen content of the waste and the chemical oxygen demand and the nitrogen content of the nitric acid wash water and of the organic or biological wastes are significantly reduced. The nitric acid wash water is the waste stream generated by descaling wet oxidation reactors used for the treatment of organic or biological wastes, especially municipal wastes. The process of this invention can be carried out in conventional above ground equipment or in a subterranean, down-hole reactor having a vertical configuration which utilizes gravitational forces to provide a high pressure reaction environment. The nitric acid wash water and organic wastes are reacted with an oxidant at a temperature greater than 150° C. and a pressure suffient to keep water in the liquid state. The nitric acid wash water is mixed with the organic waste or is introduced through the oxidant (preferably gaseous oxygen) inlet in such a manner that gas with water vapor and the remaining acid provides a liquid film so there are essentially no "dry spots" in the oxidant inlet lines.

Method for co-processing organic wastes and spent nitric acid wash water

A reaction apparatus (20) having an externalized heat exchange mechanism by which heat may be added to or withdrawn from a reactant mixture. In one aspect, a cased well (24) extends into the earth in which at least one reaction vessel (50) is suspended from a support plate (40) at substantially ground level surface (22). The reaction vessel comprises an outer closed-end tube (55) in which an inner open-end tube (60) is disposed in a concentric manner to define an annulus (70) which is in flow communication with the bore of the inner tube. Substantially parallel to the reaction vessel and also suspended from the ground level support plate, is a conduit (45) which extends into the chamber defined by the well-casing. A mixture of reactants is injected into the annulus of the reaction vessel to form a hydrostatic column which exerts substantial fluid pressure at a reaction zone in the lower part of the reaction vessel. A heat-transfer medium is heated to an elevated temperature and then flowed through the conduit into the chamber (30) where the hot heat-transfer medium envelops the reaction vessel. Heat is transferred from the heat-transfer medium to the reactant mixture through the wall of the outer closed-end tube. In the case of an exothermic reaction, when the temperature of the reactants reaches a selected level, the reaction process gives off heat which is withdrawn by the heat exchange medium. As the reactants form reaction products, the reaction products are flowed from the annulus through the bore (65) of the inner tube back up to ground surface level. In another aspect more than one reaction vessel is suspended in a single chamber in a single subterranean shaft. In still another aspect each reaction vessel comprises an inner open-end tube concentrically arranged inside a larger intermediate closed-end tube which is then surrounded by a larger tube to form a heat exchange annulus. Also suspended in the chamber with the reaction vessel is a conduit through which heat-transfer medium is pumped into the chamber during operation. The chamber is partitioned into an upper portion and a lower portion by packing assemblies or by pressurizing the upper portion with an inert gas. As heat-transfer medium flows into the chamber it is confined to the lower portion of the chamber and forced upwardly through the heat exchange annulus which is in heat-transfer relation to a hydrostatic column of reaction products in the inner reaction vessel annulus.

Dean R. Sillerud

Papers

Asymmetric heat-exchange reaction apparatus for effecting chemical reactions

Method for co-processing organic wastes and spent nitric acid wash water

Apparatus and method for effecting chemical reactions