Reactor and method for removing small molecules at low temperature

Abstract

The invention discloses a reactor and a method for removing small molecules at low temperature. A vertical two-section reactor is included, the upper section of the reactor is a cylinder, the lower section of the reactor is an inverted cone, the tail end of the inverted cone is a reactor outlet, and the outlet is connected with an external cooler. A feeding hole and a gas outlet are formed in the top of the reactor, and the reactor is also provided with a first gas inlet and a second gas inlet. The cylindrical section is divided into a first reaction area and a second reaction area. Through the design of a splitter plate, plug flow in the particle conveying process can be achieved, and backmixing is not likely to be caused. A hot nitrogen / air outlet pipe provides stable air flow for heat and mass transfer with spherical polyester particles, and the polyester particle micromolecule removal efficiency is greatly improved.

Description

technical field [0001] The invention relates to a reactor and method for removing small molecules at low temperature. Background technique [0002] Polyethylene terephthalate (PET) is a semi-crystalline thermoplastic polyester widely used in the manufacture of fibers, films, sheets as well as food trays and beverage containers. In the existing production technology, the preparation of high-viscosity polyester usually uses terephthalic acid (PTA) and ethylene glycol (EG) as the main raw materials, and the intrinsic viscosity is about 0.65dl / g and the degree of polymerization is about 100 low-viscosity polyester, and then through the solid-phase thickening process, the intrinsic viscosity is increased to 0.80dl / g, and the average degree of polymerization reaches 135 or more high-viscosity polyester, so that it can meet the requirements of subsequent processing. [0003] In polyester packaging products, in addition to intrinsic viscosity, small molecule content is another most...

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Problems solved by technology

[0004] At present, the existing reactors are all designed with conventional cylindrical polyester particle tower structure, which will lead to uneven falling speed of polyester chips depending on their own weight, low packing density of polyester particles, inability to effectively form plug flow, uneven heat exchange, It is easy to cause back-mixing. The shell-and-tube heat exchanger in the cooling section has a short cleaning cycle due to impurity precipitation, low removal efficiency of small molecules in slices, and the replacement cycle of the cooler’s dust bag is greatly affected by the outside world.

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