With the deepening of the concept of circular economy and sustainable development, the clean emission and recycling of desulfurization by-products have been put on the agenda in the desulfurization process of cogeneration and large thermal power plants. Practice has proved that with the progress of technology, the application of desulfurization technology not only purifies emissions, but also makes its by-products more and more widely used.
So, how to choose desulfurization system for coal-fired power plants? The main factors considered in the selection of desulfurization system for coal-fired power plants are: desulfurization rate, calcium-sulfur ratio, utilization rate of absorbent, availability and treatability of absorbent, influence of disposal and availability of desulfurization by-products on boiler and flue gas treatment system, influence on unit operation, influence on surrounding environment, complexity of land occupation, maturity of power utilization process, total investment and operating cost. According to different parts of desulfurization process in production, pre-combustion desulfurization, such as coal washing desulfurization; Combustion desulfurization, such as clean coal combustion, circulating fluidized bed boiler and calcium injection in the furnace; Desulfurization after combustion, such as flue gas desulfurization. Flue gas desulfurization after combustion is the main means to control SO2 pollution in the world at present. At present, there are many flue gas desulfurization methods studied in various countries, which have exceeded 100. Some of them have been tested in the intermediate stage, and some are still in the laboratory research stage. Only a dozen of them can really be applied to industrial production. The selection of flue gas desulfurization methods in thermal power plants mainly depends on boiler capacity, fuel composition, supply conditions of desulfurizer, corresponding geographical conditions, utilization of by-products and other factors. According to the reaction state of desulfurization process, the currently used flue gas desulfurization methods can be roughly divided into three categories: dry method, semi-dry method and wet method. Recommended products: DC 14 series and DC2 1 series. Practical application cases: Changchun Water Group, Shenyang Water Group, etc. BACKGROUND: At present, most domestic and foreign urban sewage treatment plants adopt primary treatment and secondary treatment. The primary treatment adopts physical methods, mainly through grid interception, precipitation and other means to remove large suspended solids and sand particles in sewage. This treatment process is relatively mature at home and abroad, with little difference.
The secondary treatment adopts biochemical methods to remove suspended and dissolved organic matter, nitrogen, phosphorus and other nutrients in sewage mainly through the life movement of microorganisms. At present, there are many ways to deal with this process. To sum up, the representative processes mainly include traditional activated sludge process, oxidation ditch, A/O or A2/O process, SPR, SBR and CCAS process. At present, these representative processes have practical applications at home and abroad. -Conditions for foam formation:
Solution: water, organic matter and mixture.
Foaming agent: surfactant, thickener, floater.
External force intervention (gas dispersed in liquid)
mix
pump
Liquid flow
The reaction produces gas.
Liquid evaporates into gas phase.
-Foam formation process and morphology:
Foam is an air cavity surrounded by a very thin liquid, and the liquid becomes bubbles. In this way, a large number of bubbles gather and become huge bubbles, which are dispersed in the liquid.
There are basically two types of foam: polyhedron and sphere.
-Bubble troubles:
Overflow container
Loss of production capacity
Reduce equipment efficiency
Increase the difficulty of work
It is easy to cause the product grade to drop.
Why choose silicone defoamer?
-silicone defoamer has obvious advantages in comprehensive use cost and environmental friendliness, and can quickly and efficiently remove foam without increasing the COD value discharged by the system. Except for some special application conditions (such as painting process), defoamers are widely used in silicone. The dosage of silicone and non-silicone is above 10- 100 ppm. It is insoluble in most systems and soluble in most systems. Advantages: extreme temperature stability/acid and alkali resistance/good foam breaking performance/good dispersibility/no increase in system COD value, no oil pollution.