Abstract: In order to provide the technological references and guides for the evaporator system design for concentration of the strong liquor from absorption reaction in simultaneous desulfurization and denitrification of flue gas with urea solute, the following studies based on the practical engineering of flue gas treatment in a large-scale brewer were carried out. First, the relative evaporative concentration properties of the strong liquor were measured. Second, a mathematical model for simulation of multiple-effect outward-heater evaporator system feed from forward was set up and the corresponding computer program was established. Third, a multiple-effect evaporator system for a flowing rate of 4.934 t/h of strong liquor was simulated and optimum number of effects according to the simulation results was selected and analyzed from an economic balance. Fourth, the scaling layer substance deposited on heat transfer surface was analyzed by X-ray diffraction analysis(XRD), Fourier transform infrared spectroscopy(FTIR) and X-ray fluorescence spectrometry (XRF). The results showed that (1) a decrease of 0.92 percent in the specific heat occurred for each percent increase in the solid content of the strong liquor, the boiling point of the strong liquor was fitted to D hring's rule; (2)from the results of simulating computation and economic analysis, the four-effect outward-heater evaporator system feed from forward for a flowing rate of 4.934 t/h of strong liquor was the best choice for operation. (3) the pickling solution can be used to clear out the scaling layer substance easily.