An innovative idea of extracting kinetic energy from man-made wind resources using ducted turbine system for on-site power generation is introduced in this paper. A horizontal axis ducted turbine is attached to the to...An innovative idea of extracting kinetic energy from man-made wind resources using ducted turbine system for on-site power generation is introduced in this paper. A horizontal axis ducted turbine is attached to the top of the chimney to harness the kinetic energy of flue gases for producing electricity. The turbine system is positioned beyond the chimney outlet, to avoid any negative impact on the chimney performance. The convergentdivergent duct causes increase in the flue gas velocity and hence enhances the performance of the turbine. It also acts as a safety cover to the energy recovery system. The results from the CFD based simulation analysis indicate that sig- nificant power 34 kW can be harnessed from the chimney exhaust. The effect of airfoils NACA4412 and NACA4416 and the diffuser angle on the power extraction by the energy recovery system using a 6-bladed ducted turbine has been studied with the CFD simulation. It is observed that the average flue gas velocity in the duct section at the throat is approximately twice that of the inlet velocity, whereas maximum velocity achieved is 2.6 times the inlet velocity. The simulated results show that about power may be extracted from the chimney flue gases of 660 MW power plant. The system can be retrofitted to existing chimneys of thermal power plants, refineries and other industries.展开更多
Coal combustion technologies are changing in order to burn coal more cleanly.Many 'clean combustion' and post-combustion technologies are developed to remove SO_2 and NO_xgases, particulate matter during combu...Coal combustion technologies are changing in order to burn coal more cleanly.Many 'clean combustion' and post-combustion technologies are developed to remove SO_2 and NO_xgases, particulate matter during combustion, or from the flue gases leaving the furnace. This paperfocuses on three types of fly ash (flue gas desulfurization (FGD) residuals, atmospheric fluidizedbed combustion (AFBC) residuals and sorbent duct injection (SDI) residuals) which produced by 'theclean combustion' and post-combustion technologies. The residuals formed by FGD are PCFA (pulverizedcoal fly ash) grains entrained with reacted and unre-acted sorbent and have lower bulk densitiesthan PCFA grains because it contains higher concentrations of calcium and sulfur, and lowerconcentrations of silicon, aluminum and iron than PCFAs. AFBC residuals consist of spent bed whichis a heterogeneous mixture of coarse-grained bed material and irregularly shaped, unfused, sphericalPCFAs. The main crystalline phases in AFBC residuals are anhydrite (reacted sorbent), quartz andlime (unreacted sobent), calcite, hematite, periclase, magnetite and feldspars. The residualsproduced by SDI contained 65 percent-70 percent PCFA with the larger sizes material beingirregularly shaped, fused or rough-edged. The reaction products of sorbent (portlandite and lime)included calcium sulfate (anhydrite) and calcium sulfate. The chemical properties of these residualsare similar to those of high calcium PCFAs because of the high alkalinity and high pH of theseresiduals.展开更多
文摘An innovative idea of extracting kinetic energy from man-made wind resources using ducted turbine system for on-site power generation is introduced in this paper. A horizontal axis ducted turbine is attached to the top of the chimney to harness the kinetic energy of flue gases for producing electricity. The turbine system is positioned beyond the chimney outlet, to avoid any negative impact on the chimney performance. The convergentdivergent duct causes increase in the flue gas velocity and hence enhances the performance of the turbine. It also acts as a safety cover to the energy recovery system. The results from the CFD based simulation analysis indicate that sig- nificant power 34 kW can be harnessed from the chimney exhaust. The effect of airfoils NACA4412 and NACA4416 and the diffuser angle on the power extraction by the energy recovery system using a 6-bladed ducted turbine has been studied with the CFD simulation. It is observed that the average flue gas velocity in the duct section at the throat is approximately twice that of the inlet velocity, whereas maximum velocity achieved is 2.6 times the inlet velocity. The simulated results show that about power may be extracted from the chimney flue gases of 660 MW power plant. The system can be retrofitted to existing chimneys of thermal power plants, refineries and other industries.
文摘Coal combustion technologies are changing in order to burn coal more cleanly.Many 'clean combustion' and post-combustion technologies are developed to remove SO_2 and NO_xgases, particulate matter during combustion, or from the flue gases leaving the furnace. This paperfocuses on three types of fly ash (flue gas desulfurization (FGD) residuals, atmospheric fluidizedbed combustion (AFBC) residuals and sorbent duct injection (SDI) residuals) which produced by 'theclean combustion' and post-combustion technologies. The residuals formed by FGD are PCFA (pulverizedcoal fly ash) grains entrained with reacted and unre-acted sorbent and have lower bulk densitiesthan PCFA grains because it contains higher concentrations of calcium and sulfur, and lowerconcentrations of silicon, aluminum and iron than PCFAs. AFBC residuals consist of spent bed whichis a heterogeneous mixture of coarse-grained bed material and irregularly shaped, unfused, sphericalPCFAs. The main crystalline phases in AFBC residuals are anhydrite (reacted sorbent), quartz andlime (unreacted sobent), calcite, hematite, periclase, magnetite and feldspars. The residualsproduced by SDI contained 65 percent-70 percent PCFA with the larger sizes material beingirregularly shaped, fused or rough-edged. The reaction products of sorbent (portlandite and lime)included calcium sulfate (anhydrite) and calcium sulfate. The chemical properties of these residualsare similar to those of high calcium PCFAs because of the high alkalinity and high pH of theseresiduals.
