Study On Surfactants Used For Black Smoke Wet Purification

At present, China is the largest producer and consumer of coal in the world, and also is one of those rare countries which take coal as fundamental resource. Imperfect combustion of coal produces black smoke made of submicron particles (the aerodynamic diameter is less than10μm), harmful to the people’s health. In this paper proprietary technology umbrella plate desulfurized dust scrubber is applied to purify and remove the waste gas simulated by the producer of black smoke (Patent No. CN200420069314.9). And also it discusses the influences of hydrophile-lipophile balance (HLB) value, critical micelle concentration (CMC), Gibbs free energy (△Gmf0) of surface active agent and different compositional proportions on the removing black smoke efficiency (η).Based on the research data in this study, the calculation formula of HLB, CMC and△Gmf0of mixing surface active agent are selected. By the comparison between the mathematical model results and experimental results, it verifies the reliability of mathematical model, providing the reference for the industry application of surface active agent to remove black smoke.The attribute test is done for the black smoke particles from china plant using coal in Liling, Hunan, and the physicochemical property of black smoke particle is investigated and also the energy spectrum analysis is conducted, which provides the reference for the selection of surface active agent. By the experiment of adding surface active agent into dust removing desulfurized installment, the performance of removing black smoke particle of umbrella plate dust scrubber is investigated and the result shows that the removing efficiency have strong relationship with the types of surface active agent, different proportion and CMC.Under the condition of inlet wind speed uin=14m/s, liquid-gas ratio0.8L/m3, inlet smoke concentration3000mg/m3, the black smoke removing efficiency is increased with the increase of concentration of surface active agent, and the increase change tendency is from rapid to slow.It can be obtained by the surface tension gauge under normal temperature that CMC of AEO-9is lmmol/L, CMC of SDBS is1.5mmol/L, CMC of CTAB is9.5mmol/L, CMC of SDS isl lmmol/L, and CMC of OP-10is0.4mmol/L.By the comparison between theoretical result of CMC and experimental result, it is found that the CMC value calculated by mathematical model conforms to the experimental result, and the relative error is less than10%. The experimental result verifies the predicted result of mathematical model well.When the concentration ratios between AEO-9and SDBS are1:0.5,1:1,1:1.5,1:2and1:10, CMC values are0.15mmol/L,0.22mmol/L,0.24mmol/L,0.32mmol/L and0.65mmol/L, respectively. When the concentration ratios between AEO-9and CTAB are1:0.5,1:1,1:1.5,1:2and1:10, the surface tensions are measured and CMC values are0.6mmol/L,1.0mmol/L,1.2mmol/L,1.3mmol/L and1.6mmol/L, respectively. When the concentration ratios between SDBS and CTAB are1:0.5,1:1,1:1.5,1:2and1:10, the surface tensions are measured and CMC values are0.83mmol/L,0.94mmol/L,0.99mmol/L,1.05mmol/L and1.20mmol/L, respectively.The compositional solutions are made of two of AEO-9, SDBS and CTAB surface active agents. When the ratio is above1:1, the dust removing efficiencies are good. When the concentration ratios are all the same, the black smoke removing efficiency are from high to low:AEO-9—SDBS, SDBS—CTAB, AEO-9—CTAB.The relationship among HLB, CMC,η and△Gmf0of tree compositional surface active agents can be presented in mathematical models. The logarithm and secondary linear relation exist in AEO-9and SDBS, that is, HLB=-1.7631n(CMC)+9.2863, η=0.0008(△Gmf0)2—0.0283(△Gmf0)+1.2174. The secondary linear relationship exists between AEO-9and CTAB, that is, HLB=-0.0907(CMC)2—0.0687(CMC)+12.636, η=-0.0017(△Gmf0)2+0.0669(△Gmf0)+0.3188. SDBS and CTAB have good relevant mathematical model: HLB=-0.0046(CMC)2+0.0132CMC+9.3616, η=-0.0122(△Gmf0)2+0.4313(△Gmf0)—2.835.CMC value can be estimated based on HLB value, and related to CMC与△Gmf0, the black smoke particle removing efficiency of surface active agent can be predicted, which is of great practical significance in development of surface active agent used for the purification of gas particles from coal combustion or integration of removing dust and desulfurization.