3results about How to "Same dwell time" patented technology

This invention provides a method and system for purifying a cyclic ester stream. The method includes the step of continuously evaporating a solution stream containing cyclic esters, thereby converting all or part of the cyclic esters into a solid state. Specifically, it includes the following steps: (a) introducing the solution stream containing cyclic esters into a continuous evaporation concentration unit, thereby converting all or part of the cyclic esters into a solid state, to obtain a gaseous solvent and a stream A containing purified solid cyclic esters; (b) introducing the stream A containing purified solid cyclic esters obtained in step (a) into a particle size control unit, to obtain a stream B containing purified solid cyclic esters; optionally, (c) introducing the stream B containing purified solid cyclic esters obtained in step (b) into a solid-liquid separation unit, to obtain a filtrate and a stream C containing purified solid cyclic esters; (d) drying the stream B containing purified solid cyclic esters obtained in step (b) or the stream C containing purified solid cyclic esters obtained in step (c), to obtain dried glycolide particles. This invention solves the technical problems of high difficulty in particle size control, insufficient chemical purity of the product, and inability to operate continuously in existing glycolide purification technologies.

The invention relates to the technical field of catalysts, and discloses a heteropolyacid catalyst as well as a preparation method and application thereof. The roundness P of the heteropolyacid catalyst is more than or equal to 0 and less than or equal to 0.8, meanwhile, the stacking density rho of the heteropolyacid catalyst is limited, and the relationship between the roundness P and the average radius Ravg is more than or equal to 0 and less than or equal to 0.95, namely (2 * rho * P) / Ravg; the catalyst can be efficiently stacked and arranged in the tube nest of the reactor, so that the catalyst is arranged more tightly, channeling and reverse mixing of feed gas among catalyst particles are effectively reduced, the utilization rate of methylacrolein can be increased in the reaction of producing methacrylic acid by oxidizing methylacrolein, and meanwhile, the occurrence of excessive reaction is reduced; therefore, the catalyst can keep high methylacrolein conversion rate and methacrylic acid selectivity at the same time. Meanwhile, the specific structure of the outer surface of the catalyst can enable the catalyst to obtain good mechanical strength, the cracking and crushing conditions of the catalyst are reduced, and the service life of the catalyst is prolonged.

The utility model relates to packing technical field, and disclose a kind of square bottom valve mouth bag efficient hot laminating device, it include: base, the top of base is fixedly connected with support seat, the top of support seat is fixedly connected with workstation, the top of base is fixedly connected with support leg, the top of support leg is fixedly connected with transmission workstation, transmission workstation top is fixedly connected with support frame;Transmission hot covering mechanism, transmission hot covering mechanism includes rotating assembly and working assembly, rotating assembly is located in the side of transmission workstation and is used for transmission work, and working assembly is located in the inner cavity of support frame and is used for hot covering work.The utility model is through the transmission chain and gear engagement transmission of rotating assembly, cooperate the inner cavity positioning structure of transmission workstation, ensure that there is no deviation, no shaking in the transmission process of bag;And transmission chain pitch is matched with bag width design, so that the residence time of each bag in hot covering area is consistent, further guarantee the consistency of laminating effect.