Extraction equipment should be considered in selection of the properties and design features
Liquid extraction is also called solvent extraction into liquid mixture with incomplete combination of liquid as the solvent, which causes the second phase, use some of the original liquid in the relations of distribution among the different between the two liquid phase separating the effective components.
This is a liquid -
Mass transfer process between the liquid.
solvent extraction technique is a kind of main material separation and purification technology, to save energy, improve resource utilization, solve the environmental pollution, etc. , there are advantages.
Liquid extraction with large processing capacity, good separation effect, high recovery rate, can continuous operation, and easy to automatic control, etc.
In the oil, hydrometallurgy, atomic energy industry, biochemical, environmental protection, food and pharmaceutical industry and other fields has been widely used.
At present, the development of the extraction technology also depends on the lab research, groped from pilot scale process conditions, and then zoom in to the industrial device.
extraction equipment choice, for a liquid-liquid extraction process, select the appropriate set various mass transfer, is one of the important work, but it's also a difficult work.
All sorts of mass transfer equipment have different characteristics, and the influence of various factors in extraction process and extraction system is complicated.
the nature of the equipment should be considered in the selection of system and design features: (
System need theory series: to accomplish a certain number of separation, extraction set each series must have the need theory.
Need less theoretical series, such as level 2, there is no mechanical stirring the set of all the heavy to choose, such as packing tower, sieve plate tower, etc.
Need theory series more, such as level 5 above, you must choose a plus energy extraction equipment, such as rotary tower, vibration tower, turbine extraction tower.
When need more theoretical series, such as rare earth extraction process often need dozens of level, and even a few hundred, generally can only choose mixer-settler at this time.
Processing: the capacity of equipment is often determined by the production task.
The required capacity is big, can choose rotary tower, sieve plate tower, turbine extraction tower;
Processing is lesser, can choose packed tower, pulse sieve plate tower and packed tower of the pulse.
Residence time: if the system of residence time in extraction operation requirements, such as in the production of antibiotics, fermented liquid extraction, often required in relatively short residence time of the extraction equipment, centrifugal extractor is optional at this time.
If the system of chemical reaction, with slower demand when we have enough time to adopt mixer-settler is appropriate.
Compared to: refers to the dispersed phase and continuous phase flow ratio, for extraction tower equipment, to produce a larger contact area, usually a large flow phase as the dispersed phase.
Compared to is too big, not stirring type tower, unfavorable choose, and should choose the stirring type tower, such as turbine extraction tower;
Mixer-settler basically is not affected by compared with the size.
System's physical properties: system the physical properties of the selection of extraction set each have a close relationship.
The big difference in density between can choose tower extractor;
Conversely should choose centrifugal extractor;
System of interfacial tension, high viscosity, should consider to have extra energy extraction equipment, to ensure that the larger contact area;
Interfacial tension is small, can choose packed tower, if the system is corrosive, should give priority to packed tower.
Equipment and operating and maintenance costs: when choosing extraction equipment, in addition to the need to consider equipment manufacturing cost, also consider equipment operation and maintenance costs.
Including set inside the material storage, especially the storage capacity of the solvent, solvent recovery cost and solvent consumption.
Installation site: installation site shall be determined according to the actual situation, area of limited should choose tower each;
If the ground height is limited, the mixer-settler could be considered.