Patent GB-381291-A (GB)
Title: Improvements relating to the treatment of liquids
IPC: B01D11/04
Filed: 1931-08-24
Abstract: <PICT:0381291/IV/1> <PICT:0381291/IV/2> An apparatus suitable for the counter-current treatment of liquids such as may be employed for nitration extraction and washing processes such as the manufacture of trinitrotoluene from mononitrotoluene comprises in combination a number of reaction vessels on one level completely isolated from one another during normal operation of the process and a number of separation vessels all at a higher level with means for lifting the liquid from a reaction vessel to a separation vessel, characterized by the feature that the channels connecting the separation and reaction vessels and along which the liquid flows by gravity are open so that the flow of liquid is visible and cleaning is facilitated. The reaction vessels may be connected together, near the tops thereof by means of channels arranged so that any surplus fluid will flow to adjacent reaction vessels.  The separating vessels may be provided with a weir over which the separated liquids pass, the separating vessels being preferably of shallow construction. In the nitration of mononitrotoluene to trinitrotoluene interaction between the liquids takes place in a number of stages each stage comprising a reaction vessel a and a separating vessel b; the reaction vessels may be fitted with a stirring gear c means being provided for heating and cooling.  In withdrawing the separated liquids from the separating vessels the lighter liquid is caused to flow over an extended edge or weir d and after flowing over the weir it is conducted along an open channel e which may be fitted with a measuring device to an adjacent reaction vessel.  The heavier liquid flows under a downwardly extending diaphragm f, then upward and over a weir g and along a channel h to the appropriate reaction vessel.  A passage i is arranged to carry if desired some of the liquid from the separating vessel back to the reaction vessel from which it came and the reaction vessels are connected together by shallow p  channels k as a safeguard against overflow.  The means for raising the liquid from the reaction vessel to the separation vessel may comprise an air lift or a mechanical impeller either vertical or at a suitable angle and the mechanical impeller may be combined with a stirrer.  The mixture is lifted to a channel m from which it flows into the separating vessel to a point as remote as possible from where the liquid flows out.  In a nitration plant nitric acid is added in small portions at the various stages.ALSO:<PICT:0381291/III/1> <PICT:0381291/III/2> An apparatus suitable for the countercurrent treatment of liquids such as the manufacture of trinitrotoluene from mononitrotoluene comprises in combination a number of reaction vessels on one level completely isolated from one another during normal operation of the process and a number of separation vessels all at a higher level with means for lifting the liquid from a reaction vessel to a separation vessel, characterized by the feature that the channels connecting the separation and reaction vessels and along which the liquid flows by gravity are open so that the flow of liquid is visible and cleaning is facilitated.  The reaction vessels may be connected together near the tops thereof by means of channels arranged so that any surplus fluid will flow to adjacent reaction vessels.  The separating vessels may be provided with a weir over which the separated liquids pass, the separating vessels being preferably of shallow construction.  In the nitration of mononitrotoluene to trinitrotoluene interaction between the liquids takes place in a number of stages, each stage comprising a reaction vessel a and a separating vessel b; the reaction vessels may be fitted with a stirring gear c, means being provided for heating and cooling.  In withdrawing the separated liquids from the separating vessels the lighter liquid is caused to flow over an extended edge or weir d and after flowing over the weir it is conducted along an open channel e which may be fitted with a measuring device to an adjacent reaction vessel.  The heavier liquid flows under a downwardly-extending diaphragm f, then upward and over a weir g and along a channel h to the appropriate reaction vessel.  A passage i is arranged to carry if desired, some of the liquid from the separating vessel back to the reaction vessel from which it came and the reaction vessels are connected together by shallow channels k as a safeguard against overflow.  The means for raising the liquid from the reaction vessel to the separation vessel may comprise an air lift or a mechanical impeller either vertical or at a suitable angle and the p  mechanical impeller may be combined with a stirrer.  The mixture is lifted to a channel m from which it flows into the separating vessel to a point as remote as possible from where the liquid flows out.