Desulfurization wastewater zero discharge treatment system and process

The invention relates to the technical field of desulfurization waste water treatment, and discloses a desulfurization waste water zero discharge treatment system and process, a desulfurization waste water preheater can realize condensate (low in starting temperature and gradually increased later) generated in the previous evaporative crystallization operation, and preheat and heat the next desulfurization waste water at the same time; firstly, the sensible heat of the condensate can be utilized to the maximum extent, so that the temperature of a condensate discharge system is maintained at a lower constant value (only one heat transfer temperature difference higher than that of the desulfurization wastewater stock solution) in batch operation; secondly, the heat exchange area of preheater equipment is small, and the cost is reduced; in addition, chemical softening is not needed, the cost of chemical softening is saved, and the system is integrally arranged and occupies a small area; in addition, the steam co