Comparison of technical solutions
(1), the existing traditional process to meet the basic environmental requirements, according to the three-phase phase diagram, the physical separation method, but the separation process is cumbersome and incomplete separation, the salt extraction products are thiocyanate, mixed salt (thio A mixture of sulphate, ammonium sulphate, thiocyanate), after the salt is extracted, the wastewater needs to be further processed or returned to the desulfurization system.
(2) The technology meets the high environmental protection requirements, and uses a combination of physical and chemical methods to convert the waste liquid from a three-salt to a two-salt liquid, and the separation waste liquid is further separated and purified by a reverse osmosis membrane. 70% meet the direct discharge standard or cooling circulating water requirements, and the remaining 30% return to the desulfurization system is used as supplemental water.
Salt extraction products are high quality thiocyanate, ammonium sulfate, sulphur-free sulphate products
The specific Technical index is as follows: (HPF method, ADA method directly extract salt)
| Technical index content | Traditional craftsmanship | Current technology | |
| Salt extraction rate (%) | ≥95.0 | ≥99.5 | |
| Thiocyanate extraction rate (%) | ≈60 | ≥95 | |
| Waste liquid after salt extraction | PH | 10-12 | 6-9 |
| Steam consumption (tons of steam / ton of waste) | ≥1.5 | ≤0.8 | |
| COD(mg/L) | 10000—30000 | Meet the 《Water Quality Standard for Recycled Water for Circulating Cooling Water》 HG/T 3923-2007 | |
| Ammonia nitrogen (mg/L) | ≥10000 | ||
| Going direction of waste liquid | Continue water treatment or return to the desulfurization system | ||
| Water balance of desulfurization system | Can not meet the water balance of the desulfurization system | Satisfy | |