Hot wastewater concentrate fluidizing, crystallizing, and drying system and method of hot air pressure variable circulation

Abstract

The invention discloses a hot wastewater concentrate fluidizing, crystallizing, and drying system and method of hot air pressure variable circulation. According to the system and method, air is introduced into the system through an air inlet unit and heated by a first heat exchanger to obtain hot air; hot air is taken as carrier gas and is introduced into a fluidizing, crystallizing, and drying tower through the air inlet of the tower; a spherical filler, which is between the inner cylinder and outer cylinder of a rotation roller is blown into a micro-floating fluidized state; hot wastewater concentrate, which is preheated by a preheater and heated by a second heat exchanger, is distributed to an atomizer arranged on the inner cylinder of the rotation roller, the wastewater concentrate isatomized and sprayed on the surface of the spherical filler so that the wastewater concentrate can exchange heat with the hot air, water is taken away by hot air, wet saturated air is obtained, salt in concentrate is dried and cured on the surface of the fluidized spherical filler; along with the rotation of the inner cylinder and the flowing of hot air, due to the grinding and collision between the spherical fillers, salt falls into a crystal collection conical bucket arranged in the bottom of the tower after going through the mesh screen of the outer cylinder; compressed wet saturated air isphase-changed and heat-exchanged in a preheater and then condensed to form dehumidified air, and the dehumidified air is introduced into the pressure variable circulation of the air inlet unit aftergoing through an air expanding unit.

Description

technical field [0001] The invention relates to the field of waste water treatment, relates to the terminal solidification of waste water, and in particular to a system and method for fluidized crystallization and drying of hot waste water concentrated liquid in a hot air pressure swing cycle. The waste water concentrated liquid can be desulfurized waste water concentrated liquid. Background technique [0002] The desulfurization wastewater zero discharge system generally includes three parts: a pretreatment unit, a concentration reduction unit, and a terminal solidification unit. [0003] At present, the terminal curing technologies adopted at home and abroad mainly include: evaporative crystallization drying, direct injection flue crystallization drying, bypass flue crystallization drying, and hot air crystallization drying. [0004] Evaporation and crystallization drying: The evaporative crystallization process consumes a lot of steam and / or electricity, occupies a large ...

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Problems solved by technology

[0006] (1) After the desulfurization wastewater evaporates, highly corrosive chlorides cannot be completely collected by the electrostatic precipitator, causing them to accumulate on the desulfurization tower and subsequent equipment, causing severe corrosion, and significantly increasing the frequency and cost of equipment maintenance;

[0007] (2) Materials such as heavy metals in desulfurization wastewater are enriched in fly ash, which greatly affects the reuse of fly ash and the safety of users

[0008] (3) After the wastewater is atomized, it will cause severe corrosion and scaling to the flue, electrostatic precipitator and downstream equipment, which will affect the long-term stable operation of the equipment. For example, the fouling of the electrode plate of the electrostatic precipitator will reduce the dust removal efficiency and even affect the electrostatic precipitator. normal operation

[0009] (4) The atomizing nozzle and the flue are severely worn, coupled with the corrosion of high-concentration chloride, the equipment fails quickly

[0010] (5) The process mainly relies on the electrostatic precipitator to remove the evaporation crystallization products. The substances that the electrostatic precipitator cannot remove will return to the desulfurization tower with the flue gas, and will be enriched continuously, increasing the load of the desulfurization tower, and causing PM2.5 and mercury Emissions are easy to exceed the standard

[0012] Hot air crystallization drying: requires a lot of steam, high energy consumption, unusable products, difficult to handle

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