Optimization Of A Novel Liquid Slag-removal Burner And Study Of Particle Deposition Characteristics

Liquid slag-removal burner is a combustion technology with low investment, highsection burning capacity, high slag capture and low dust content in the flue gas, whichhas wide range of applications in our country. However, traditional cyclone burner withtuyere structure decorates in a single side, which makes a asymmetric flow field andcauses temperature field distortion, weakens the backflow phenomenon. At the sametime, it is easier to slag near the tuyere and make combustion instability. Therefore, theresearch and development of new liquid slag-removal burner has important academicsignificance and project value.On the basis of analyzing the advantages and disadvantages of liquid slag-removalburners, a novel liquid slag-removal burner is developed. The structure sizes of burnerare designed primarily. Meanwhile, by studying the flow, combustion and particledeposition characteristics, an optimal structure and the best running condition isobtained, which is beneficial to enhance the combustion performance and can realizeslag tapping.Taking the designed burner as physical model, the realizable k-ε model, DPMmodel and the non-premixed combustion model are used to study the influence on flowand combustion characteristics of the burner of different structure and operationparameters. The results show that:①Flow field is axisymmetric in this burner. Anobvious and stable center recirculation region is formed on the effect of the blunt bodyand vortex leaves, which can entrain enough high temperature flue gas to combustionand ignition.②A better flow field has obtained while the leaning angle (β1), therotating angle (β2) of secondary wind pipe, primary-air expansion angle (α) is20°,51°,60°respectively with optimizing the structure of burner. Meanwhile, the characteristicsof the temperature field can meet the requirements of high temperature slag tapping.③Good center recirculation region is organized while the primary air ratio is0.35and theexcess air coefficient is0.9. At the same time, high efficiency combustion and low NOxemission is achieved.Then, thermal state experiment is studied on three different heat load (50%,75%,100%) of the burner with optimal structure, the results show that: When running in threedifferent load, the combustion efficiency exceed80%and the central temperature ishigher than1780K, the burner can achieve slag tapping, which shows a high load adjust ability of the burner. The numerical simulation results tally with the experiment results.Finally, particle deposition is simulated on the influence of the particle size,structure and operation parameters of the burner. The results show that:①Smallerparticle is better for following the flow and not easy to deposit, a few deposit in frontburner. Particle larger than60μm has a deposition rate higher than98%, which leads tohigh slag capture.②The peak deposition velocity of particle increases with thedecreases of β1, the increases of β2and α and the increases of excess air coefficient,meanwhile, the peak position moves to the front burner. However, it is no good foruniform distribution and easy to cause pulverized coal jam in the low temperatureregion of the anterior burner with excessive deposition velocity and the peak positionmoves forward.