3 results about "Supercritical carbon dioxide" patented technology

The invention relates to the field of preparation of biologic oil, and provides a furfural catalytic hydrogenation method under supercritical carbon dioxide and a method for preparing catalysts. The furfural catalytic hydrogenation method under supercritical carbon dioxide comprises the steps that furfural and palladium and carbon catalysts are added to a reaction still, then the reaction still is sealed, hydrogen is introduced into the reaction still to remove the air in the reaction still, liquefied carbon dioxide is injected into the sealed reaction still through a plunger metering pump, the pressure of the carbon dioxide is made to be above the critical pressure when the carbon dioxide is in an overcritical state, furfural catalytic hydrogenation and upgrading are carried out under the overcritical condition of the carbon dioxide, and a needed liquid product is prepared. The method for preparing the palladium and carbon catalysts comprises the steps of pre-processing of a carrier and preparation of the palladium and carbon catalysts (Pd/C catalysts). In the reaction process, the catalysts have no carbon accumulation phenomenon, can be recycled, largely reduce generation of by-products, and improve the selectivity of the products.

The invention relates to chemical production equipment and a process, in particular to a supercritical carbon dioxide extraction process flow in combination with a urea production system. The process flow is characterized by forming a fluid source compressor set for supercritical carbon dioxide extraction by combining an original or new carbon dioxide compressor in the urea production system according to the process conditions of supercritical carbon dioxide extraction: singly using the carbon dioxide compressor operating in the urea production system, or singly using the standby carbon dioxide compressor, or singly using the new carbon dioxide compressor or selecting to use one of the different combinations of the three kinds of carbon dioxide compressors to compress and use surplus carbon dioxide in the system as the supercritical fluid source of supercritical carbon dioxide extraction and introducing the surplus carbon dioxide into a supercritical carbon dioxide extraction system to form the supercritical carbon dioxide extraction process flow. The process flow fully uses the surplus material and human resources, improves the production efficiency, reduces the disposable investment, lowers the operation, maintenance and management cost and realizes energy saving, emission reduction and consumption reduction.

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.