HKY-1Spray device for supercritical reaction fine particles

1Principle and Overview of the Device

Supercritical spray technology is a subject emerging in modern chemical separation, and it is an advanced separation process rising in the world at present. The so-called supercritical fluid refers to a fluid whose thermodynamic state is above the critical point (Pc, Tc), which is the point where the gas liquid interface has just disappeared. Supercritical fluid has very unique physical and chemical properties, with a density close to that of a liquid and a viscosity close to that of a gas. Its characteristics such as high diffusion coefficient, low viscosity, and high dielectric constant make it a good solvent for separation. Supercritical extraction refers to the process of contacting a solvent with the extracted substance in an extraction cylinder under high pressure and appropriate temperature, allowing the solute to diffuse into the solvent, and then changing the operating conditions in a separator to precipitate the dissolved substances for separation purposes.

Supercritical device selected CO₂As a supercritical extractant, the medium has the following characteristics:

1. Wide operating range, easy to adjust.

2. Good selectivity, targeted extraction of desired components can be achieved by controlling pressure and temperature.

3. The operating temperature is low, and extraction is carried out under conditions close to room temperature, which is particularly suitable for thermosensitive components. The extraction process eliminates the possibility of oxygen oxidation and visible light reactions,

Extracts can maintain their natural flavor.

4. The extraction and separation are completed in one step, and the extracted CO₂No residue on the extract.

5 CO₂Non toxic, odorless, non flammable, affordable and easy to obtain, and recyclable.

2、 Preparation of fine particles for continuous operation.

The main work process is: CO₂Pump will transfer CO₂Sent to the top of the crystallization, the pressure of the crystallizer is controlled through a valve. CO₂Cool to below 0 ℃ with a cooler before entering the pump to prevent cavitation. The crystallizer is installed in an air bath, and its temperature is adjusted by a temperature controller, heater, and circulating fan. The separator is installed after the crystallization kettle, and the temperature is controlled by water bath circulation. After the system stabilizes, the pressure is released through the pressure relief valve, and the sub millimeter droplets sprayed from the nozzle through the pressure difference are dispersed in a continuous medium composed of solvent resistant gas. Due to the expansion and evaporation of reaction particles, solute particles are precipitated through crystallization. There are glass tubes and metal filter plates inside the crystallizer to collect particles. After achieving partial granulation in the crystallization kettle, CO₂The mixture with most of the liquid leaves the crystallizer and enters the * stage separator through a mist nozzle, where it is depressurized. Due to the sharp drop in pressure, the solution instantly reaches supersaturation during this process, resulting in the precipitation of fine solute particles. Afterwards, CO₂Enter the second stage separator with the solvent mixture and reduce the pressure to achieve CO₂Separate from the solvent, and then recycle the two separately. After collecting enough particles, stop the solution supply and continue to introduce CO₂Using CO in the crystallizer₂Remove residual solvents from the particles.

3、 Safety precautions

1. The entire device must have a safe and reliable grounding to prevent electric shock and injury.

2. Each component and pipeline process has its own safe working pressure, which must not be exceeded during operation, especially when using CO₂Special care is required when using gas, as the instrument comes with two sets of safety protection devices.

3. When using constant temperature heating, turn on the equipment in the order of startup.

4. After the equipment is used up, it should be cleaned in a timely manner to prevent rust or blockage of pipelines.

fourMain technical parameters

1. Zui high extraction pressure: 50MPa.

2. Single cylinder reaction volume: 1L.

3. Reaction temperature: room temperature to 250 ℃.

4. Maximum flow rate: adjustable from 0 to 50L/h.

5. Magnetic stirring

fiveThe main components of the device

The supercritical fine particle reaction spray device consists of the following parts: CO with purity ≥ 99%₂Gas cylinder (provided by the user), refrigeration device, temperature control and display system, mixing system, pressure control and display system, spray system, safety protection device, carrier tank, purifier, mixer, heat exchanger, storage tank, mixing reactor with flow of 50L, 1L/50MPa, 1L/30MPa separator, electric control cabinet, valves, pipe fittings, cabinet frame, etc. See the following schematic diagram for the specific process.

6、 Preparation before startup

1. Firstly, check if the power supply and three-phase four wire are intact. （AC380V/50HZ）

2. Is the cooling water source of the freezer and storage tank unobstructed? The cold box contains a 30% ethylene glycol+70% aqueous solution.

3 CO₂The pressure of the gas cylinder is guaranteed to be between 5-6 MPa, and the net weight of food grade is ≥ 22kg.

4. Check whether the pipeline joints and various connection parts are secure.

5. Add cold water to each hot box, not too full, about 2 centimeters away from the box cover.

6. Load the raw materials into the mixing kettle, and the raw materials should not be installed too full, about 2-3 centimeters away from the filter screen.

7. Cover the pressure ring and upper plug.

8. Fix the nozzle onto the separation vessel.

5、 Startup operation sequence

1. First, turn on the air switch. If the three-phase power indicator lights are all on, it means the power is connected, and then turn on the (green) button of the power supply.

2. Turn on the cooling switch and also turn on the water circulation switch.

3. Start heating, first turn on the mixing kettle, separation I, separation II, and heating switch, and adjust their respective temperature controllers to their desired set temperatures.

4. After the temperature of the freezer drops to around 0 ℃ and the temperatures of the reactor, separation I, and separation II approach the set requirements, perform the following operations.

5. Simultaneously start cooling and release CO₂The gas cylinder enters the purifier, cooling pipe, and storage tank through valves, CO₂Perform liquefaction, liquid CO₂Enter the extraction cylinder through a pump, mixer, and purifier (the extraction cylinder is already filled with samples and the plug is closed). After the pressure is balanced, open the exhaust valve of the extraction cylinder, slowly release residual air, reduce some pressure, and then close the exhaust valve.

6. Apply pressure: First, set the electrode point to the required pressure (upper limit), then start the green button of pump I,. When the pressure reaches near the set pressure (about 1MPa in advance), start opening the throttle valve behind the reaction kettle. How to adjust it specifically depends on the following different flow directions:

ⅰ) Reaction kettle → separator (spray) I → separator II → circuit

Ii) Reactor → separator I → separator II → circuit

When stopping the pump midway, simply press the STOP button on the digital operation.

Open the valves of the stirring reaction kettle and the separation kettle, and use high and low pressure (differential pressure) to release, expand, and react the reaction medium from the nozzle. After the reaction is complete and there is no pressure, open the reaction cylinder head, remove the residual material, and the entire reaction process is complete.

9. Separate the substances separately at valve a₂Valve A₃Take it out.

6、 Precautions and troubleshooting

1. This device is a high-pressure flow device. Those who are not familiar with the system process are not allowed to operate it. During high-pressure operation, do not leave the post. If any abnormal situation occurs, immediately stop the machine and turn off the main power for inspection.

2Refrigeration system

① Before starting up and during normal operation, it is necessary to check whether the oil level of the compressor is normal. Generally, there is no shortage of oil. If it is too low, special oil for the refrigeration unit should be added^#The new model is 40^#）

② When the refrigeration unit is running normally, the high pressure gauge indicates 1.5-2Mpa in summer and 1-1.5Mpa in winter (high pressure protection 2.2MPa), and the low pressure gauge indicates 0.2-0.3Mpa. If the cooling effect is poor due to low temperature, R22 Freon can be added appropriately. (Can be added from the low-pressure valve port)

③ Before starting the refrigeration unit, both the high and low pressure gauges have pressure, but after starting up, the low pressure gauge is 0, and the refrigeration unit frequently starts and stops, which may be due to clogged filters, expansion valves, or solenoid valves.

The processing steps are as follows:

A、 Close the liquid supply valve of the storage tank, start the cooling machine switch, recover Freon, and turn off the cooling machine when the low pressure gauge drops below zero.

B、 Open the filter and clean the filter screen at the bottom of the expansion valve (filter core).

C、 After cleaning, install the filter and expansion valve, close the high-pressure valve, open the vent joint to evacuate the refrigeration unit until the low-pressure gauge is less than 0 and there is no air at the high-pressure outlet.

D、 Tighten the high-pressure vent joint (cap), then open the high-pressure valve and supply valve.

Note: The above situation is an abnormal phenomenon. If it occurs, please seek professional assistance to resolve it.

3、CO₂fluid system

①CO₂When running the pump, check if there is cooling circulating water (supplied in the cold box) at the pump head.

② When starting to pressurize, wait for the refrigeration temperature of the cold box to reach the required level, and at the same time open the vent valve at the outlet of the pump for venting.

③ It should be checked whether the electric contact pressure gauge controls the pump to stop (manually tested and checked).

④ Due to CO₂Or if the material contains water, there may be ice blockage in the high-pressure coil inside the cold box. The fault phenomenon is that the pressure display of the storage tank is low (lower than CO)₂And the outlet pressure cannot circulate. resolvent:

A、 Regularly drain water from the bottom valve of the purifier.

B、 If there is ice blockage, open the cold box cover and let the temperature of the cold box naturally rise to room temperature. Blow nitrogen gas from one end of the coil to the other end until the moisture is dried.

4Heating and temperature control system

① When starting up, it is necessary to check whether the three-phase four wire power supply is correct and prohibit phase loss operation.

② Check the water level of each heating water tank every time it is turned on (per shift). If it is not enough, it should be replenished in a timely manner (due to high temperature evaporation), otherwise it will burn out the heating tube. At the same time, it is necessary to check whether the water pump motor is running to prevent scale from jamming the shaft and burning out the motor.

③ If the measured temperature is much higher than the set temperature, or if the water in the water bath is boiling, it may be due to the breakdown of the bidirectional thyristor, which does not have a control effect. In this case, simply replace the corresponding thyristor.

5. The pump needs to replace the lubricating oil within a certain period of time.