DIMETILOVY AIR OF P-PHTHALIC ACID, DIMETHYL TEREPHTHALATE, P-PHTHALIC ACID, WAYS OF PRODUCTION, PARAXYLOL, RECTIFICATION, TARGET PRODUCT, BY-PRODUCTS, COST OF PRODUCTION, TECHNOLOGICAL SCHEME.
Due to the aggravation of competitive fight for sales markets producers of fibers, and also producers of monomers for them not only expand the productions, but improve and intensify technological processes. It is promoted by reorganization of periodic processes on continuous, and also cut in expenditure on initial raw materials to which share the main expenses fall. One of actions for improvement of processes - replacement of dimethyl terephthalate in production of polyair on a p-phthalic. It became possible after development of ways of receiving p-phthalic acid of high degree of purity.
Thanks to high resistance to a sminaniye and ability to keep a form, good appearance and rather low cost polyester fibers in pure form or in mix with other fibers use for production of the wide range of consumer goods: clothes and costume fabrics, the top jersey, curtains, bed linen, products from artificial suede and fur fabric.
Essential value in improvement of technical and economic indicators has fuller extraction of by-products and research of ways of their rational use. So, DMT fraction - DMI can apply to receiving polioksadiazol, and - as preservative.
1 — the oxidation reactor; 2 — a settler; 3 — the eterifikation reactor: 4, 5,6 — rectification columns; 7 — the device for dissolution; 8 — a crystallizer; 9 — the centrifuge; 10, 11 — columns; 1 — a plavilnik of DMT; 1Z — capacity. I \catalyst; II \p-xylol;;;;;;;;; III \air; IV \methanol; V \p-metiltoluilat;;;;;;;;; VI drains; VII \pure DMT;
One of the most important ways of increase of efficiency of process of oxidation of mix of a p-xylol and methyl air p-toluilovoy acids is use of large-capacity reactors of oxidation. Thus the special attention has to be paid to development of the knots of gas distribution providing the maximum surface of contact of phases, to effective hashing of an oksidat and heat removal of reaction. Creation in the reactor of necessary hydrodynamic conditions, increase warm and a mass exchange it is possible to increase significantly productivity of installations, to lower metal consumption of the equipment.
Further improvement of processes of receiving DMT has to go first of all on the way of creation of power technological schemes; decrease in account indicators on raw materials; regenerations of the catalyst; fuller extraction of target products from the remains; improvements of the equipment, systems of automation and management.
Excess of methyl alcohol is deleted from a reaction zone at the top of the reactor of an eterifikation 3, subjected to rectification in a column 4 and returned in a cycle. The vat rest from a rectifying column 4 and condensate of the easily boiling components which take away at the top the reactor of oxidation 1, send to a settler there is a mixture and division of two phases on organic and water Here. The organic layer comes back to oxidation, and water goes to drains.
The DMT-raw from an otparny column 3 comes to rectifying columns 5 - 7 in which drive away the easily boiling impurity and the heavy remains. The pure DMT leaving from top of a rectifying column 7 goes for casing.
Literary data on technical and economic indicators of the existing productions of synthetic fibers and monomers for DMT - are very limited. However on the basis of the available data on construction of plants it is possible to judge tendencies of development of some ways. receiving the specified product.
The analysis of capital investments in production of synthetic fibers and monomers for them in the developed countries shows, what much attention is paid to these productions in the USA, Germany, Japan and other countries now.