Abstract: Provided a method for separating PHA and PHA prepared therefrom. The method comprises the following steps: subjecting a PHA fermentation broth to solid-liquid separation to obtain a thallus precipitate; breaking cell walls of the thallus precipitate, and subjecting obtained wall-broken products to a plate and frame filtration to obtain PHA; a filter cloth for the plate and frame filtration is pre-coated with a PHA layer. The method adopts a plate and frame separation to replace the traditional centrifugal separation to prepare PHA, and the PHA layer is pre-coated on the filter cloth for the plate and frame filtration, thereby overcome the defects in the prior art such as high cost and operational difficulty caused by adopting multiple centrifugal separations; in addition, the method of the present disclosure also exhibits the advantages of high recovery rate of PHA and high purity of the prepared PHA product.

Abstract: The present invention relates to the field of high polymer material manufacturing, and discloses an air-isolated continuous feeding system for synthesizing polylactic acid from lactide and a feeding method thereof. The continuous feeding system comprises a raw material bag/box and a raw material collector for collecting and outputting lactide, the raw material bag/box is connected with a shielding gas input pipeline, a discharge pipe is movably inserted into the raw material bag/box, a cyclone separator is connected downstream of the discharge pipe, and a solid substance outlet of the cyclone separator is connected with the raw material collector. According to the invention, deterioration of the lactide raw material incurred by moisture absorption and oxidation is avoided, and the reaction conversion ratio and final product purity are improved. The continuous feeding system is easy to operate, can save manpower and material resources, and is applicable to industrial application.

Abstract: The present invention relates to the field of high polymer material manufacturing, and discloses an air-isolated continuous feeding system for synthesizing polylactic acid from lactide and a feeding method thereof. The continuous feeding system comprises a raw material bag/box and a raw material collector for collecting and outputting lactide, the raw material bag/box is connected with a shielding gas input pipeline, a discharge pipe is movably inserted into the raw material bag/box, a cyclone separator is connected downstream of the discharge pipe, and a solid substance outlet of the cyclone separator is connected with the raw material collector. According to the invention, deterioration of the lactide raw material incurred by moisture absorption and oxidation is avoided, and the reaction conversion ratio and final product purity are improved. The continuous feeding system is easy to operate, can save manpower and material resources, and is applicable to industrial application.

Abstract: Provided a method for separating PHA and PHA prepared therefrom. The method comprises the following steps: subjecting a PHA fermentation broth to solid-liquid separation to obtain a thallus precipitate; breaking cell walls of the thallus precipitate, and subjecting obtained wall-broken products to a plate and frame filtration to obtain PHA; a filter cloth for the plate and frame filtration is pre-coated with a PHA layer. The method adopts a plate and frame separation to replace the traditional centrifugal separation to prepare PHA, and the PHA layer is pre-coated on the filter cloth for the plate and frame filtration, thereby overcome the defects in the prior art such as high cost and operational difficulty caused by adopting multiple centrifugal separations; in addition, the method of the present disclosure also exhibits the advantages of high recovery rate of PHA and high purity of the prepared PHA product.

Abstract: A method for efficiently producing PHA comprising: inoculating PHA fermentation strains into a fermentation medium for fermentation under the condition of being capable of producing PHA through fermentation; subjecting the fermentation broth to a solid-liquid separation to obtain fermentation supernatant and thallus precipitate; breaking the cell walls of the thallus precipitate, and subjecting the wall-broken products to a plate and frame filtration to prepare PHA; pre-coating a filter cloth for the plate and frame filtration with a PHA layer; at least part of the water of the fermentation medium is PHA process wastewater. The method utilizes the PHA process wastewater as at least part of the water of the fermentation medium, and filters and separates the broken thallus with the plate and frame filtration equipment pre-coated with PHA layer to prepare PHA, thereby recycling the high-salt wastewater, reducing costs, and potentially separating PHA on a large scale for industrial production.

Abstract: The present disclosure relates to the technical field of polymer material, and discloses a device and method for online preparation of a modified polylactic acid material with a polylactic acid melt. The device comprises a twin-screw extruder, a first solid modifier hopper, a polylactic acid melt pipeline and a polylactic acid melt feedstock metering pump, wherein the first solid modifier hopper is connected with Zone I of the twin-screw extruder, the polylactic acid melt pipeline is connected with Zone IV of the twin-screw extruder. The method for online preparation of modified polylactic acid material with the device can avoid degradation of the polylactic acid caused by the secondary processing, improve mechanical property of the prepared polylactic acid and reduce production cost.

Abstract: The present disclosure relates to the technical field of biotechnology and polymer synthesis, and discloses a method for producing polylactic acid, the method comprises the following steps: (i) inoculating a lactic acid fermentation strain into a lactic acid fermentation culture medium to perform a fermentation, so as to obtain a fermentation broth containing lactate; (ii) separating the fermentation broth to obtain a lactic acid; (iii) synthesizing a polymer-grade lactide by using the lactic acid as a raw material; (iv) subjecting the polymer-grade lactide to a polymerization reaction in a polymerization reaction device to obtain a polylactic acid. Through the above technical solution, the polylactic acid can be efficiently produced in the present disclosure.

Abstract: The present invention relates to the technical field of polylactic acid preparation, and discloses polylactic acid polymerization reaction apparatus and system. The polylactic acid polymerization reaction apparatus comprises a polymerization reactor and an agitating assembly arranged in a flow channel of the polymerization reactor, wherein the agitating assembly comprises an electromagnetic winding mechanism and a magnetic induction element, the electromagnetic winding mechanism is arranged along the inner wall of the polymerization reactor around the magnetic induction element, with clearance formed between the electromagnetic winding mechanism and the magnetic induction element, so that the magnetic induction element and the electromagnetic winding mechanism can induce electromagnetic induction, and thereby the magnetic induction element can rotate around its own axis; a threaded groove is formed on the magnetic induction element.

Abstract: The present invention relates to the field of devolatilization, and discloses a polylactic acid devolatilization evaporator, which comprises: a container comprising a cylinder; an agitating shaft coaxial with the cylinder; an agitating belt connected to the agitating shaft and arranged in a spiral shape around the central axis of the cylinder, comprising an outer belt surface facing the inner circumferential surface of the cylinder and spaced apart from the inner circumferential surface of the cylinder. With the above technical scheme, the agitating belt makes the materials distributed more uniformly on the inner circumferential surface of the cylinder and form a thin layer in uniform thickness, thereby avoids agglomeration of the materials, facilitates uniform heating of the materials, avoids deterioration (e.g., darkened color) of the materials owing to non-uniform heating of the materials and excessive retention time in a high-temperature environment, and improves product quality.