Noram International Limited

Sergio Berretta

Clive Brereton

Alfred A Guenkel

David Anthony Boyd

A method of safely vaporizing liquid chlorine containing high concentrations of nitrogen trichloride contaminant from a chloralkali plant. In a vertical plug-flow vaporizer having an upward flow direction, a stream of liquid chlorine containing nitrogen trichloride is received. A gas such as air, nitrogen or chlorine gas is introduced into the liquid stream upstream of the boiling zone of the vaporizer to induce a flow regime, for example annular flow or mist flow, that prevents a mass accumulation of nitrogen trichloride in the vaporizer. The liquid chlorine containing nitrogen trichloride is vaporized. The resulting gas stream may be processed to destroy the nitrogen trichloride and recycled to the chlorine production train.

Method and apparatus for vaporizing liquid chlorine containing nitrogen trichloride

A method and apparatus for removing non-aromatic impurities from non-nitrated aromatic reactant in a nitration production process, in which process an aromatic reactant is nitrated () to produce a nitrated aromatic product using a molar excess of the aromatic reactant, and non-nitrated aromatic reactant is recovered () from the produced nitrated aromatic product and is recycled () for use in the nitration production process. A portion of the removed excess non-nitrated aromatic reactant is diverted () and subjected to nitration (). The nitrated stream may be further processed by separating out the spent acids () and the non-aromatic impurities (). These streams may be sent () to a suitable location in the nitration production train.

Removal of non-aromatic impurities from a nitration process

A method of removing alkalinity and salt from a nitroaromatic product downstream of water washing to remove mineral acids and alkaline washing to remove salts of organic acids, comprises washing the product stream with an acidic aqueous solution, prior to the step of removing excess organic reactant, by steam stripping or distillation. Acid removed from the stripper or column is recycled back for use in the acidic washing. The acidic washing is done instead of the neutral washing step of the prior art. It removes residual salt and decreases the level of entrained colloidal water in the nitroaromatic product.

Washing system for nitroaromatic compounds

An adiabatic process for making mononitrobenzene by the nitration of benzene which minimizes the formation of nitrophenols and dinitrobenzene by-products. The process uses a mixed acid having less than 3 wt % nitric acid, 55 to 80 wt % sulfuric acid, and water. The initial temperature of the mixed acid is in the range of 60 to 96&#xb0; C. The nitration reaction is complete in about 300 seconds and produces less than 1,200 ppm nitrophenols and less than about 80 ppm dinitrobenzene. The reaction can be carried out in a plug-flow or a stirred pot reactor, or a combination of such reactors.

Adiabatic process for making mononitrobenzene

A method for making mononitrobenzene using a plug flow reactor train. Benzene, nitric acid and sulfuric acid are introduced into the reactor and produced mononitrobenzene is removed at an outlet end. All of the benzene and at least part of the sulfuric acid are introduced at the inlet end of the reactor. A first portion of the nitric acid is introduced by a first nitric acid feed into the inlet end and a second portion of the nitric acid is introduced at one or more additional feeds that are spaced between the inlet end and the outlet end. The method results in reduced formation of by-product dinitrobenzene, improving the reaction yield of mononitrobenzene while avoiding the need for a distillation step.

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Vancouver, Canada

Sergio Berretta