6 basic common sense of industrial supercritical CO2 extraction machine
Industrial supercritical CO2 extraction machines are large supercritical fluid systems.
Under normal circumstances, the composition of the extraction system is: 2-3 extraction containers, 2-3 separation and collection containers, special machines are equipped with fractionation columns; the composition of special models is composed of a multi-stage fractionation column and a three-stage separation container.
In order to facilitate the operation, the extraction kettle lid of the industrial supercritical CO2 extraction machine adopts the clamp-type hydraulic automatic quick opening structure.
Extraction working medium
Carbon dioxide, the working CO2 gas can be recycled in the CO2 extraction process.
The difference between laboratory and small and medium-sized CO2 extraction is that the industrial-grade CO2 extraction machines are fully automatically controlled, and the extraction, separation pressure, and temperature are all automatically controlled, and remote computer monitoring of parameters can be realized. The series and parallel operation of valves are all automatically controlled. During the working process, the maximum working pressure of each extraction kettle is controlled by a pressure detection sensor, a safety valve, and a control signal interlocking quadruple method, which is safe and reliable.
All the inner walls, pipes, and pipe fittings in contact with materials are made of stainless steel with acid and alkali resistance that is suitable for GMP requirements, generally SUS304.
Gas recovery systems are standard on industrial supercritical CO2 extraction machines
, because some gas will be lost in the CO2 extraction process, so the medium CO2 in the extraction process of the industrial CO2 extraction machine must be recyclable to achieve the purpose of maximizing the use of CO2.
Note: After our many years of experience, the gas loss during the standard CO2 extraction process is about 33% of the extracted raw material.
The higher the CO2 extraction pressure, the higher the pressure on the extraction vessel and the pipeline, and the higher the requirements for equipment manufacturing. The extraction vessel and pipeline manufactured on the basis of existing materials will require thicker wall thickness. It means high manufacturing costs and larger machine volumes.
Different from small CO2 extraction machines, the maximum working pressure of industrial CO2 extraction machines needs to take into account the actual production requirements and cost control. The design pressure is 350bar and the maximum working pressure is 320bar.
Energy-saving and environmental protection
Temperature control is an important parameter in the CO2 extraction process. All containers and pipelines of CO2 extraction equipment will have a certain temperature difference with the production environment. Therefore, all containers and pipes of the industrial CO2 extraction machine are insulated with rubber-plastic foam materials and are covered with stainless steel sheets. The overall equipment is beautiful and generous.
What are the components of an industrial supercritical CO2 extraction machine?
The industrial CO2 extraction machine is composed of a CO2 injection system, extraction and separation system, CO2 circulation system, cleaning system, carrier system, chilled water circulation system, hot water circulation system, rack platform, control system, and exhaust gas recovery system, etc.
Extraction and Separation Systems
The liquid CO2 is pressurized to the extraction pressure by the CO2 high-pressure pump and flows through the preheater.
The material basket of the extraction kettle is filled with raw materials and is hoisted into the extraction kettle by an electric hoist. The pure supercritical CO2 enters from the bottom of the extraction kettle and passes through the material cylinder to the top of the extraction kettle during the process of CO2 dissolution and extraction of the effective components in the raw materials.
- The extraction section consists of 3 extraction kettles. The three extraction kettles can be used in parallel or in series.
- The CO2 entrains the extract stream into the separation unit. The separation is performed in two steps.
- The CO2 entrained with the extract flows from the extractor through the first control valve to the primary separator. Through the throttling control of the control valve, some extraction components are resolved through the pressure drop in the primary separator, and the separated material can be received from the bottom of the primary separator.
- The CO2 entrained with the incompletely separated extract flows to the secondary separator through the pipeline. Through the throttling control of the control valve, the low-pressure extraction components are separated and decomposed in the second separator and can be received from the bottom of the secondary separator. isolate.
- The extraction and separation system includes CO2 high-pressure pump, extraction heater, extraction kettle (including quick-opening device), material cylinder, separation kettle 1, separation 1 heater, separation kettle 2, and separation 2 heaters.
CO2 recycling system
After the extraction, the CO2 in the extraction kettle is recovered to the CO2 intermediate storage tank through the separator. When the pressure of the extraction kettle and the pressure balance of the intermediate storage tank is reduced to 50bar, the CO2 tail gas in the extraction kettle that has been extracted is discharged into the empty kettle to be extracted, and the remaining pressure in the extraction kettle that has been extracted after the two pressures are balanced The pressure of about 2MPa is recovered through the exhaust gas recovery system.
The CO2 gas (excluding extract) flows into the precooler, is initially condensed by the precooler, flows into the CO2 intermediate storage tank, and is deeply cooled in the intermediate storage tank.
The CO2 circulation system mainly includes a CO2 intermediate storage tank and condenser.
According to the user’s process requirements, the carrier agent in the cosolvent (carrier agent) storage tank can be injected into the entire extraction and separation system through the carrier agent pump at any time when the equipment is working.
The co-solvent system mainly includes a co-solvent storage tank and co-solvent pump.
When the extraction equipment needs to replace the material, when the equipment work is completed, the cleaning agent in the cleaning agent storage tank is filled into the entire equipment pipeline for cleaning through the cleaning agent pump.
The cleaning agent system mainly includes a cleaning agent storage tank and a cleaning agent pump.
Chilled water circulation system
The tap water is injected into the pure water device, and after purification, it flows into the cold water tank and is pumped into the refrigerator by the cold water pump. After cooling, it returns to the cold water tank. In the water jacket of the intermediate storage tank and other containers, the medium is cooled. When the temperature of the medium in a container is higher than the process temperature
Then, through the automatic adjustment valve adjustment, the cooling water circulation system of the container is cut off, and the cooling of the medium in the container is stopped; when the temperature of a certain container is lower than the process temperature, the cooling water circulation system of the container is opened by adjustment through the automatic adjustment valve, and the cooling water circulation system of the container is opened. The medium in the container is cooled; automatic adjustment ensures the process temperature of the medium in each container.
The cooling water circulation system mainly includes a cold water storage tank, water pump, and refrigerator (including a cooling water tower).
Hot water circulation system
The tap water is injected into the pure water device, and after purification, it flows into the hot water tank and is pumped into the atmospheric pressure heater for heating by the hot water pump. Distributed to the water jacket of the extraction kettle, separation kettle, heat exchanger, heater, and other containers respectively to heat the medium. When the temperature of a container is higher than the process temperature, the hot water circulation system of the container is cut off by adjusting the automatic regulating valve; when the temperature of a container is lower than the process temperature, the hot water circulation system of the container is opened by adjusting the automatic regulating valve. Start heating the medium in the container; automatically adjust to ensure the process temperature of the medium in each container.
The hot water circulation system mainly includes a hot water storage tank, water pump, and atmospheric pressure heater.
Exhaust gas recovery system
After the extraction is completed, the carbon dioxide pump is turned off, and the pressure in the extraction kettle and the separation kettle is circulated to the carbon dioxide intermediate storage tank; after the system pressure is balanced, the remaining gas in the extraction kettle is discharged into another empty extraction kettle that has been filled with materials to be extracted. After the pressure is balanced, the remaining gas is discharged into the tail gas buffer tank, and the carbon dioxide in the tail gas buffer tank is compressed by the compressor to the intermediate storage tank for recycling.
The tail gas recovery system mainly includes a tail gas buffer tank and tail gas recovery compressor.
The control system is mainly composed of a low-voltage power distribution cabinet, PLC control cabinet, extraction kettle quick-opening chain control cabinet, industrial control computer, refrigeration unit control box, etc. The low-voltage power distribution cabinet contains electrical control components such as circuit breakers, contactors, thermal relays, and frequency converters. The PLC cabinet contains electrical control components such as PLC modules, intermediate relays, and DC24V power supplies.