The Study Of Desulfurization Characteristics And Application Of Solid Waste In Circulating Fluidized Bed Boiler

The technology of coal which fixed sulfur in the Circulating Fluidized Bed is in order to meet environmental requirements and to develop advanced coal combustion technology, but because of the by-products of Circulating Fluidized Bed coal combustion, which named Circulating Fluidized Bed Coal Combustion slag containing solid sulfur minerals are in the process of hydration in significant volume expansion and other reasons. To limit the use of desulfurization slag, and even affect the promotion of this large-scale coal-fired technology. This paper selects the ashes of FBC to study the expansion law and the expansion mechanism different fineness desulfurization residues, the ashes which is prepared by using different grinding fineness CFBF.In this paper, scanning electron microscopy（SEM） on the ground desulfurization slag and desulfurization slag undisturbed morphology be studied, and the influence of the fineness of ground slag desulfurization performance also be studied; by macroeconomic indicators, such as strength, volume the stability of the ground desulfurization slag as a cement admixture as well as ground desulfurization slagclinker system for the concrete cementitious materials has been studied by X-ray diffraction（XRD） to contain glue residue desulfurization system hydration products hardening materials were analyzed. The results show:Sulfur ground slag particle size distribution is narrowed, the original porous granular structure has been improved; the ash fineness of desulfurization become more thinner and the hydration reaction become more rapid, when the phase in the same age, the degree of fineness the of hydration desulfurization ash have high compressive, and flexural strength of mortar in the same age will be greater; the XRD patterns which comes from 1d age FBCF were free of the CaO absorption peak; from 1d to 28 d, the content of ettringite has grow trends; the anhydrite peak at 28 d decreased significantly.The SO₃ of FBCF is existed by the form of II-CaSO₄. in the form of dissolved IICaSO₄ CaSO₄ · 2H2 O crystals generated when solid volume expansion, and the dissolved SO₃ reactive with the active Al2O₃, the f-CaO, the AFt solid volume would be expansion. Because of f-CaO is wrapped of II-CaSO₄, it has a greater impact on the expansion of FBCF.FBC ashes in SO₃ is II-CaSO₄ exists in the form of hydration products crystallize the resulting product was dissolved CaSO₄·2H2O, ettringite is causing a major component of FBC ashes hardening system volume expansion, in addition, is II- CaSO₄ package f-CaO also have some impact on the system. CFBC ash of CaO content is less than that required for the hydration process SO₃, or the active Al2O₃ content less than the needed hydration process SO₃, SO₃ content relative surplus that FBC ashes expansion is due to the hydration products of calcium alum stone and gypsum common cause. FBC ashes of CaO content than the required amount of SO₃ hydration process, or activity Al2O₃ content of more than the amount needed to SO₃ than the hydration process, the relative lack of SO₃ content, then the expansion of FBC ashes only cause ettringite. Although the system of excess SO₃ content, volume expansion occurs due at least in the gypsum hydration age 14 d later, that II-CaSO₄ dissolution reached saturation solubility crystallized gypsum hydration occurred in late. If the system SO₃ content in excess of free calcium oxide reaction with water to precipitate Ca（OH）2 only occurred in the early hydration, hydration does not exist in the late Ca（OH）2 due to the volume expansion; if the system less SO₃ content of free calcium oxide content relative surplus, which requires completely depleted, the free lime hydration reaction occurs with water II-CaSO₄ precipitated Ca（OH）2, in the late hydration caused by volume expansion.