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Nutsche filter glass reactor for Winterization

Nutsche filter glass reactor for Winterization

https://chemistryequip.com/100l-jacketed-filter-glass-reactor/

Plant waxes are a barrier to self-protection, and their main components are various lipophilic compounds that form a hydrophobic layer on their surface, which can limit non stomatal water loss, resist UV radiation, defend against pests and diseases, and so on, and are important for plant growth.Natural spices are an important component that cannot be replaced by daily spices, however, in the process of preparing extracts from natural plants, it is inevitable to extract waxes from the plant surface into the extraction solution, and the low solubility of waxes in ethanol, water, will affect the product quality of the obtained extracts, causing problems such as suspensions and poor solubility during use.In addition, this kind of wax containing plant extracts, when used, can cause adverse effects on the taste and aroma of the action object, and therefore, how to quickly and effectively remove the wax and improve the product quality of natural spices, is one of the difficulties in the development process of natural spices.At present, the production process mainly involves removing plant waxes by ethanol re dissolution followed by low-temperature freezing, i.e., the extract is dissolved and placed in – 20 to 10 ° C for low-temperature sedimentation, so that the plant waxes precipitate with other insoluble materials, followed by filtration or centrifugation to remove them.

Factors affecting deparaffinization

1. Dewaxing temperature and cooling rate

Since both hydrocarbyl carbon chains in the wax molecule are long, there will be a more severe undercooling during crystallization, which, combined with the lipophilicity of the wax hydrocarbyl group, makes it reach the freezing point, a supersaturation phenomenon.To ensure the deparaffinization effect, the deparaffinization temperature must be controlled below the point of wax setting, but also not with the fat splitting out from the oil along with the wax, increasing the deparaffinization loss of the oil.Deparaffinization was performed by the conventional method, the crystallization temperature of which was mostly controlled at about 20 ° C, and the solvent method was used for deparaffinization.

Crystallization of wax is a physical change process and the process is slow.The whole crystallization process can be divided into three steps: the over cooling of the first molten wax containing grease, the over saturation, the formation of the second crystal core and the growth of the third crystal.The wax has a higher melting point and can naturally crystallize to precipitate at room temperature.Naturally crystallized grains are small and vary in size, and some are gelatinized in oils, making the separation of oil and wax difficult.Therefore before crystallization, the oil temperature must be adjusted so that the wax crystals melt completely, and then the crystallization process is artificially controlled to create good separation conditions in which one grain is large and firm.The size of grains depends on two factors, the speed w of crystal nucleus generation and the crystal growth speed Q.The dispersity of grains is proportional to w / Q, which should decrease during crystallization and increase Q.

The cooling rate is very dependent on W and Q.When the rate of cooling was sufficiently slow, the high melting point wax precipitated crystallization first, and at the same time, the heat of crystallization.The temperature continues to drop, and the wax with a lower melting point will also precipitate crystallization.The molecules of wax that are about to precipitate collide with the wax that has been crystallized, and moreover, it grows up with the already precipitated wax crystals as the core, making the grains large and few.If the cooling rate were faster and the high melting point wax had just precipitated, it would not have come to collide with the lower melting point wax, and the lower melting point wax had precipitated separately, making the grains many and small and the entrapment of oil necessarily much too.To maintain a suitable cooling rate, the temperature difference of coolant and oil is required to not be too large, otherwise, a large number of crystal nuclei will form on the cooling surface, which is not only conducive to heat transfer but also to oil – wax separation.The cooling process is to be carried out slowly, and it should not be too slow from the production point of view, and the suitable cooling rate can be determined by the cooling test.

2. Crystallization time

Cooling must be carried out slowly in order to get crystals easily isolated, as described above.Moreover, when the temperature gradually drops to a predetermined crystallization temperature, it also needs to be kept at this temperature for a certain time to undergo crystallization (or aging, ripening).The grains continue to grow during the trophic process.It can be seen that sufficient time is required from the formation of crystal nuclei to the growth of crystals into large and firm crystals.

3. Stirring rate

Crystallization is to be carried out at low temperatures, and it is an exothermic process, so cooling is necessary.Stirring allows cooling everywhere in grease to be uniform.Stirring can make the crystal nuclei collide with the molecules of wax that are about to precipitate, and promote the grains have more chance to grow uniformly.No stirring can be done only by Brownian motion and crystallization is too slow.But stirring too fast will break the grains.The general stirring rate was controlled to 10-13 rpm and larger diameter crystallization tanks were used at a lower speed.The stirring speed was in favor of wax crystal growth.Stirring may reduce the formation of “” crystal clusters “”.In crystallization, besides the crystal nuclei grow up, several crystals may also aggregate into crystal clusters, which can encapsulate oil inside and increase the deparaffinization loss.

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