A fixed valve contact tray for use in a mass transfer or heat exchange column and having a plurality of fixed valves distributed across a tray deck of the contact tray. Each of the fixed valves has a valve cover that is wider than and extends outwardly beyond an underlying opening in the tray deck, a perimeter region of the valve cover that is beveled downwardly, and a boundary region of the opening that is raised above a plane of the tray deck.

The present invention relates to a mass transfer tray comprising a bottom plate, at least one gas transmission part and a liquid transmission part, wherein the mass transfer tray has at least one valve located in the liquid transmission part, relates to use of a mass transfer tray of the present invention in liquid separation process, relates to a column comprising the trays of the present invention, and relates to a thermal separation process, comprising performing thermal separation within the column of the present invention.

A production system, production method and application of general-purpose high-purity chemicals are disclosed. The production system includes a raw material tank, and an adsorption system, a crystallizer, a first light-impurity removal tower, a first heavy-impurity removal tower, a second light-impurity removal tower, a motorized tower, a second heavy-impurity removal tower, a vapor permeation device, a membrane separation system and a filling system connected with the raw material tank in sequence. The high-purity chemicals produced by the above system have high purity and excellent quality. Compared with the prior art, the system and method designed by the present disclosure have more pertinence, integrity, progressiveness, energy-saving, precision, high safety coefficient and great industrial promotion value. And the products produced are of excellent quality, which can meet the standards applied to the manufacturing of integrated circuit electronic components and meet the high-end needs of the semiconductor industry market.