Nitrochlorobenzene Ring Nitration Numerical Simulation And Engineering Applications

Based on analysis on the technology of chlorobenzene nitrating, the fluid field in an annular nitrating pot is simulated, including several flow regimes, velocity and hydrostatic pressure distributions, by 2 softwares both GAMBIT and FLUENT.The annular nitrating pot is a two-phase reactor for nitration of chlorobenzene, in which the mixture of nitric acid and sulfuric acid reacts with chlorobenzene under the conditions of a certain temperature and agitation strength. Resulting from a strong agitation of axial-flow agitator and a fast heat remove of tubular heat exchanger, the annular nitrating pot with large mass circulation has such advantages as high reactive rate of chlorobenzene, small volume of equipment, convenient adjustment and control, wide working range and continuous operation. In practice, different mixing rate of nitric acid and sulfuric acid, various operational efficiencies of the annular nitrating pot and varied reactive rate of chlorobenzene appear very frequently, in view of changed agitators and geometrical sizes of annular nitrating pots.Through numerical simulation on the inner fluid field of annular nitrating pot, observation on its fluid field distribution and change on the geometrical sizes of annular nitrating pot and agitator, the optimum fluid field distribution is obtained, with the method of computational fluid mechanics, application of GAMBIT software on drawing physical model, dividing meshes and determining boundary condition, and the treatment of FLUENT software on finding solution.An improved scheme is presented to raise the heat exchange effect of annular nitrating pot, based on the simulation values of the fluid field in the current annular nitrating pot. With a real direction to production, the fluid field distribution is modified obviously by use of fluid flap.