Systems and methods for removing one or more pesticides from a cannabis product are provided. The method includes dissolving, in a solvent, a cannabis product including one or more pesticides, forming a dissolved solution, and cooling the dissolved solution to a cooling temperature, causing the cannabis product to precipitate from the dissolved solution, wherein, at the cooling temperature, the one or more pesticides remain dissolved in the dissolving solution. The method further includes removing the precipitated cannabis product from the dissolving solution. The disclosed method is suitable for removing one or more pesticides from various cannabis products containing natural cannabinoids, cannabinoids acetates, cannabinoid carboxylates, or the like.

A method for preparing a purified styrene composition with a styrene yield of at least 80%. The method comprises providing a crude composition containing styrene, and subjecting the crude composition to at least one crystallization step. The at least one crystallization step comprises at least one static crystallization stage and at least one dynamic crystallization stage.

An ultrasound crystallization device comprises a tubular crystallization reactor (102) for conducting process fluid containing substance to be crystallized, an ultrasound source (104) for radiating ultrasound to the tubular crystallization reactor, and a temperature-control structure (105) for controlling the temperature of the process fluid with the aid of temperature-control fluid. The tubular crystallization reactor is shaped to conduct the process fluid to flow around the ultrasound source, and the temperature-control structure comprises a flow-guide structure (106) for guiding at least a part of the temperature-control fluid to flow around the ultrasound source. The flow-guide structure improves the accuracy of the temperature control of the process fluid and also the ability of the temperature control to react to changes.

Provided are sodium hypochlorite pentahydrate crystal gains that have high bulk density and increase bulk density in a container and improve transport efficiency by controlling the shape of the sodium hypochlorite pentahydrate crystals, and a production method thereof.

As a result of stirring or circulating by pump an aqueous solution of sodium hypochlorite pentahydrate in a crystallization tank in a crystallization step, sodium hypochlorite pentahydrate crystal grains are obtained having an average aspect ratio of 2.5 or less.

A method for preparing a purified styrene composition with a styrene yield of at least 80%. The method comprises providing a crude composition containing styrene, and subjecting the crude composition to at least one crystallization step. The at least one crystallization step comprises at least one static crystallization stage and at least one dynamic crystallization stage.

The present invention relates to the technical field of chemical industry, and in particular to a method for purifying ethylene carbonate through dynamic crystallization, which includes the following steps: adding an ethylene carbonate-containing raw material into a cavity of a crystallization device under a condition of stirring for dynamic crystallization, wherein the crystallization device further includes a jacket attached and circumferentially disposed along the outer wall of the cavity, the jacket is provided with cooling water therein, a temperature of the cooling water is 1-2.5? C. lower than the temperature in the cavity until a granular ethylene carbonate crystal is generated. The present invention using a rake dryer as the crystallization device to realize dynamic crystallization at a certain rotating speed. The technical solution is simple to operate and short in processing cycle, which facilitates improvement in production efficiency and product quality and is suitable for industrial application.

The present application relates to a method for preparing L-methionine crystals with an improved bulk density. As the L-methionine crystals prepared according to the method for preparing L-methionine crystals of the present application may have a bulk density of up to 800 g/L, the L-methionine crystals are expected to reduce storage and transport costs of L-methionine powder and improve working conditions due to improved fluidity of the powder.

A method for purifying methacrylic acid, including mixing raw material methacrylic acid and methanol; precipitating a crystal of methacrylic acid from the mixed solution; and separating the crystal and mother liquor, wherein the raw material methacrylic acid and methanol are mixed so that a concentration of methanol in the mixed liquid is 3.0 to 3.75% by mass, and the crystal of methacrylic acid is precipitated from the mixed solution in a cooling crystallization vessel.

The present invention relates to a method of producing and purifying a high-purity anhydrosugar alcohol in high yield by a simple process and apparatus, the method includes the steps of: allowing a sugar alcohol to react in the presence of an acid catalyst in a reactor, and, at the same time, evaporating a product of the reaction; cooling the evaporated product to remove water and obtain a crude anhydrosugar alcohol; and introducing the crude anhydrosugar alcohol into a melt crystallization process to obtain a high-purity anhydrosugar alcohol.

A crystallization column and a crystallization method. The crystallization column comprises an upper head (1), a tower body (2) and a lower head (3), wherein a crystallization section (11) is provided with a tray (14); and the tray (14) comprises a tray plate (15) and a plurality of lower crystallization members (17). The top end of the lower crystallization member (17) can form a movable connection with the tray plate (15), so that the two adjacent lower crystallizing members (17) are capable of oscillating collisions. The tray (14) may also comprise a plurality of upper crystallization members (21) extending upwardly from the upper surface of the tray plate (15).