Numerical Simulation Of Internal Flow In Direct-Fired Coal-Fired Hot Gas Furnace

Direct-fired coal-fired hot gas furnace is a kind of heat source device which relies on the hot flue gas produced by coal combustion and mixed with natural air to output the mixed hot gas which is clean and can reach the required temperature,which has wide adaptability,high combustion efficiency,stable output heat load and easy adjustment of hot air temperature,etc.It is widely used in chemical industry,building material and environmental protection field.In this paper,the research object is Direct-fired coal-fired hot gas furnace and mainly studied from two aspects:gas-phase simulation and gas-solid two-phase simulation.The re-sults of gas-phase simulation are analyzed and discussed,which provide theoretical basis for gas-solid two-phase simulation.Firstly,the three-dimensional model of the simplified hot gas furnace was established in Solidworks software.Then,it is introduced into the ICEM software to modify appropriately and to divide the grid,set the boundary conditions,etc.Finally,in FLUENT software,the simulation calculation and the corresponding post-treatment are car-ried out.The results of the gas-solid two-phase simulation are as follows:Through the ob-tained temperature distribution cloud,velocity distribution cloud,pressure distribution cloud and its associated turbulence reaction rate distribution cloud,C02 content distribution cloud,etc.It can be seen that the high-temperature zone in the hot gas furnace occurs mainly in the combustion area of the combustion chamber,where there is a large amount of volatiles,the rapid combustion consumes large amounts of oxygen and releases large amounts of carbon dioxide and heat;In the first-level settlement,the windshield wall by the radiation tempera-ture is high,the more particles to be burned down.The hot flue gas flow in the whole hot gas furnace is in the negative pressure state,the flow is very smooth,and the flow in the furnace is very gentle.In the two turn flow velocity and turbulent kinetic energy is larger.After the second level of settlement,the temperature gradually decreased,hot smoke is basically clean.Influence of the Structure of Reflected Arch and Settling Chamber on the Performance of Hot Gas.The results of the structural changes after the analysis,and compared with the pre-vious conclusions are as follows:the extension of reflected arch in the hot fume furnace is helpful to increase the temperature of the hot flue gas in the outlet.However,the temperature in the high-temperature combustion area of the combustion chamber is apt to cause the prob-lem of coking and slagging in the combustion chamber.The velocity around the settling chamber is increased,which is not conducive to the deposition of impurity and ash in the hot flue gas.The shortening of the reflection arch in the hot gas furnace contributes to the im-provement of the temperature of the hot flue gas,and the temperature of the high-temperature combustion region in the combustion chamber decreases.The velocity around the settling chamber is increased,which is not conducive to the deposition of impurity and ash in the hot flue gas.The prolongation of the windshield wall in the deposition chamber of the hot flue gas helps to raise the temperature of the high temperature combustion zone in the combustion chamber,but the temperature of the hot flue gas at the outlet does not change;Decreasing the velocity around the settling chamber helps to improve the cleanliness of the hot exhaust gas.Decreasing the wind-wall in the deposition chamber of hot gas furnace can help to improve the temperature of hot flue gas,but it is not conducive to the deposition of impurity and ash in hot flue gas.