Study On Flow Gas Desulfurization (FGD) With Pyrolusite Slurry

Judging the gradually serious pollution of SO₂, the boiler with coal must be taken measurement to remove it. Row Gas Desulfurization (FGD) with Pyrolusite Slurry, with the high removal efficiency and wide use of its product in both industry and agriculture has been paid more and more attention to study and exploit especially for our country with abundant Pyrolusites.This article is based on mechanism of SO₂ and MnO₂ reaction. The effect of SO₂ removal and Mn amount with the different co-exist components of (SiO₂, Fe₂O₃, Al₂O₃, CaCO₃, MgO, CoCl₃, Ni) is studied. And the pilot-scale study on SO₂ removal with pyrolusite slurry (gas amount is 7000¹0000Nm3/h) using a jet bubble reactor (JBR) is carried out. The removal ratio of SO₂ and extraction rate of manganese under the conditions of simulated and actual dim, liquid-solid ratio, different purity of pyrolusite, temperature are studied. And the stability and reliability are studied under under 72h continuous run. At last, study of MnSO₄ production by the Mn solution created by the pilot-scale experiment is carried out.In the single component study, It found that the removal of SO₂ is most affected by Ca and Mg, which is over 15%, then, Ni and Co, the effect of Si and Al are not serious. While Fe, Ni and Co affects the Mn amounts most. During the extraction of Mn, other components created at the same time, but with low concentration, which is good for the purifying of MnSO₄.And in the experiment with the component react together, take CaCO₃, MgO, Fe₂O₃, SiO₂. CoCl₃ and Ni as six most important factors to change by orthogonalexperiment. It is indicated that the ratio of SO2 removal and the extration of Mn are related with the ratio between those compounds in the expeirmens and their content in the actual pyrolusite slurry. The optimum ratio is 1: 1, 1: 1, 2.5: 1, 3: 1, 1: 1, 1: 1 for the ratio of SO2 removal and 1: 1, 1.5: 1, 1: 1, 1: 1, h 1, 1: 1 for the extration of Mn.In the pilot-scale experiment, resistance of the whole system is 4300Pa, which mainly concentrated on the JBR reactor,and all devices ran steady and with no jam, no leak, which indicated the resonablility of pilot-scale process. Under the cold simulant fume, the SO2 removal efficiency can remain 90% with long time, while under the hot fume, remian 95%, higher than the former and with Mn extraction 75%. When the the pyrolusite powder granularity about 150 u m, it can not only reduce the power by grinding, but also can get high the SO2 removal efficiency. The JBR reactor can adopt well to the low liquid-solid ratio, from the result of pilot-scale experiment, the lower the ratio, the higher the SO2 removal efficiency and extraction of Mn. Althrough the SO2 removal efficiency do not change abviously under the MnC>2 content of 21% and 42%, the extration of Mn would be lower and residue be more with low pyrolusite slurry of Mn(>2. The quality of its by-product MnSO4 ? H2O after decontamination can meet the standard HG/T2962-1999.With the above-mentioned method treating a boiler with 25t/h, the ower can not noly save above 0.28 million yuan of dumping fee, but also benefit 5.47 million from the MnSO4 by the lixivium. Addionationally, it can integrate the environment, social and economy benefits well.