ejector performance simulation for impurity separation of trinitrotoluene (tnt)

Trinitrotoluene (tnt) is one of the most widely used compounds in civilian industries like mining, dyes, and photographic chemicals, etc. during the tnt production, some undesired nitrotoluenes are present. the use of vacuum technology has been effective in separating and purifying nitrotoluene impurities. one of the effective methods in purifying tnt compounds is the use of an ejector, which, by creating a vacuum as well as ultrasonic conditions, makes it possible to separate the impurities. thus, the objective of the present research is to use a special design obtained from coding and optimization of the device geometry to remove and purify nitrotoluene compounds. the effect of different parameters (primary pressure on mass flow rate of primary and secondary flows, isentropic efficiency coefficients on mass flow rate of fluids, constant area section to throat cross section, exit diameter of primary nozzle to throat diameter, and primary fluid temperature) on ejector  performance was investigated. the cfd tool and comsol multiphysics software 5.6 were used to simulate the ejector and to validate the data. in the second part of the simulation, dwsim software was used to ensure that the use of these operating conditions is applied to purify nitrotoluene compounds. the results showed that the ejector at very low pressures and high temperatures could concentrate tnt in crude tnt (84 wt%) to 98.45 wt% in the final product.