Study Of Fluid Flow,Heat Transfer And Thermal Stress Of The Waste Heat Boiler Tube Sheet Cooling Chamber

The waste heat boiler(WHB)is a core equipment in the gaseous hydrocarbon non-catalytic partial oxidation process,and used to recover the waste heat of the high temperature syngas.The stable condition of it is essential for the safe,stable,long-periodic,and high-efficiency process operation.Temperature of the inlet syngas throungh the boiler's cooling chamber is up to 1250?1350?,which leads to serious thermal stress and threats system security.Numerical model has been established for the chamber in this thesis.Computational fluid dynamics and thermal stress analysis are coupled to investigate the effect of syngas inlet temperature,speed,cooling water inlet mode and temperature on the flow distribution and heat transfer of it.Therefore,a suitable chamber structure is determined.And the result shows that decreasing the syngas inlet temperature and increasing the cooling water inlet temperature can reduce the thermal stress,which is significant for maintaining the safe and stable operation of the device.The cold experimental equipment is designed based on the industrial device.The residence time method has been adopted to determine the flow of cooling water around the tube and outlet.Result shows that the cooling water around the tube has little back-mixing and strong jet effect.The residence time distribution of the outlets is similar and smooth,which means the flow field is uniform.Particle deposition experiment shows the good flow condition near the tube and no stagnation zone in there.The WHB syngas inlet temperature is reduced from 1250? to 1000? through an reformed heat recovery process.And materials and energy balances are calculated.Thermal stress analysis is used to evaluate the effect of the corundum tubes and the inlet temperature.Industrial operation can achieve stable operation by appropriately reducing the inlet temperature and attaching the corundum tube inside the syngas tube of the WHB.