METHOD OF CONTROLLING TECHNOLOGY OF PRODUCING DRY CO-EXTRACTS FROM VEGETABLE RAW MATERIALS Russian patent published in 2024 - IPC C11B1/10 

FIELD: oil and fat industry.

SUBSTANCE: method of controlling the technology of producing dry CO₂-extracts from plant material, which involves extraction of milled plant material with particle size of 0.5-8.0 mm with carbon dioxide in subcritical at pressure of 10-15 MPa and temperature of 10-30 °C for 15-60 minutes or in supercritical state CO₂ at pressure of 15-40 MPa and temperature of 40-50 °C for 30-60 minutes, supplied by a fluid pump to a double-column extractor with a variable operating mode of columns in an extraction mode and a spent material unloading mode; multiple circulation of carbon dioxide through a layer of crushed vegetal raw material with reversible pumps, separation during separation of carbon dioxide vapours from liquid extract in a flow-through gas-liquid separator. Compression compression of separated carbon dioxide vapours to pressure of 15 MPa in a two-stage compressor and their condensation at temperature of minus 40 °C at recuperative heat exchange with antifreeze, heating carbon dioxide to a subcritical or supercritical state during recuperative heat exchange with a mixture of hot and cold water, the temperature of which is 55-60 °C, with its return to extraction in closed cycle mode; spray drying of the liquid extract with conditioned air with moisture content of 0.005 kg/kg at temperature of 55-60 °C to obtain dry extract powder with moisture content of 1.5-3.0 % and equivalent particle diameter of 0.3-2.0 mm; fine purification of air spent after spray drying to content of dusty fraction of not more than 30 mg/m³, condensation of moisture from spent air at temperature minus 10 °C by means of recuperative heat exchange with antifreeze in a two-section apparatus with alternating operation of sections in condensation and regeneration modes; heating of conditioned air to temperature of 55-60 °C at recuperative heat exchange with hot water with temperature of 65-70 °C. At that, preparation of hot water is carried out at recuperative heat exchange with freon R123 with its condensation temperature of 75-80 °C in first stage condenser of cascade three-stage heat pump, and preparation of antifreeze with temperature of minus 45 °C is carried out at recuperative heat exchange with boiling at temperature of minus 50 °C with freon R1270 in the third stage evaporator of the cascade three-stage heat pump. Method comprises controlling process parameters according to current information obtained from sensors, according to which measured the amount of vegetal raw material loaded into extractor columns; flow rate and temperature of carbon dioxide supplied to the extractor column operating in extraction mode; period of time of flow movement in a mode of reverse circulation of liquid carbon dioxide through a layer of crushed vegetal raw material in an extractor column operating in an extraction mode; duration of the extraction process; flow of separated carbon dioxide vapours from liquid extract in gas-liquid separator; carbon dioxide liquefaction pressure and temperature; consumption of waste plant material and liquid extract; fluid extract pressure generated by spray drier nozzle; consumption and moisture content of dry extract; moisture content and air flow rate before and after drying; moisture condensation temperature from waste air in section of two-section apparatus operating in condensation mode; working medium compression pressure and working medium pressure after throttling, working medium condensation temperature and boiling point in the first, second and third stage of the cascade three-stage heat pump; temperature and flow rate of antifreeze fed for liquefaction of carbon dioxide; temperature and flow rate of hot water supplied for heating liquefied carbon dioxide and air, as well as for defrosting a section of a two-section apparatus for condensation of moisture, operating in a regeneration mode; and controlling the flow rate and pressure of subcritical or supercritical carbon dioxide depending on the volume of the loaded ground vegetal material by acting on the drive power of the fluid pump when filling the double-column extractor column operating in the extraction mode; time-programmed control of the mode of reverse circulation of subcritical or supercritical carbon dioxide through a layer of crushed vegetal raw material in a double-column extractor column operating in extraction mode, with change in the direction of movement of CO₂ by reversible pumps; controlling the temperature and flow rate of air supplied to the spray dryer, according to the flow rate of the liquid extract after the gas-liquid separator; pressure stabilization in spray dryer nozzle; determining the amount of moisture evaporated from the liquid extract from the measured values of the moisture content of the air before and after the spray dryer and its flow rate; control of antifreeze flow rate of air supplied for condensation of water vapours from air into a section of a two-section apparatus for condensation of moisture, operating in condensation mode; calculation of the current value of the heat transfer coefficient on the cooling surface of the section of the two-section apparatus for condensation of moisture from the air, operating in the condensation mode based on the measured values of the flow rate and temperature of the air at the inlet and outlet of this section, as well as the temperature of the antifreeze in this section; correction of the ratio of "air-antifreeze" flow rates according to the signal of deviation of the current value of the heat transfer coefficient from the specified value by affecting the flow rate of the antifreeze supplied to the recuperative heat exchange with air; switching the section of the two-section apparatus for condensation of moisture from the air from the condensation mode to the regeneration mode when moisture content of the conditioned air exceeds the specified value.

EFFECT: invention increases accuracy and reliability of obtaining dry CO₂-extracts.

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