High-Flux Triple Bed Circulating Fluidized Bed (TBCFB) Gasifier for Exergy Recuperative IGCC/IGFC

The flow behavior of silica sand, of average particle size 128 μm, was investigated using a large-scale triple-bed combined circulating fluidized bed (TBCFB) cold model, which was composed of a 0.1 m I.D. ×16.6 m tall riser, a solids distributor, a 0.1m I.D. × 6.5 m long downer, a gas-solids separator, a 0.75 m × 0.27 m × 3.4 m bubbling fluidized bed and a 0.158 m I.D. × 5.0 m tall gas-sealing bed (GSB) with a high solids mass flux. The main focus of this study is to determine effect of riser secondary air injection on solids mass flux (Gs) and solid holdup. Gs slightly increased by secondary air injection when the riser gas velocity (Ugr) was less than 10 m/s. This was caused by the increase in the pressure difference between the GSB and the riser. Secondary air injection had little influence on the solid holdup in the riser. The mixing between silica sand and coal particles was investigated for two different coal feeding arrangements by coupling Computational Fluid Dynamics (CFD) with the Discrete Element Method (DEM). The results show a tangential arrangement provided better mixing than a normal arrangement except near the entrance

FLOW BEHAVIORS IN A HIGH SOLID FLUX CIRCULATING FLUIDIZED BED COMPOSED OF A RISER, A DOWNER AND A BUBBLING FLUIDIZED BED

A circulating fluidized bed coal gasifier cold model which consists of an acrylic riser, a downer, and a bubbling fluidized bed were set up. Flow behaviors were investigated using silica sand with the solid mass flux up to 336 kg/m2•s. The effects of the solid inventory and the seals between the three reaction zones on the solid mass flux were investigated and discussed

Advanced Energy Saving and its Applications in Industry

The conventional approach for energy saving in a process system is to maximize heat recovery without changing any process conditions by using pinch technology. “Self-heat recuperation technology” was developed to achieve further energy saving in the process system by eliminating the necessity for any external heat input, such as firing or imported steam. Advanced Energy Saving and its Applications in Industry introduces the concept of self-heat recuperation and the application of such technology to a wide range of processes from heavy chemical complexes to other processes such as drying and gas separation processes, which require heating and cooling during operation.   Conventional energy saving items in a utility system are applied and implemented based on a single site approach, however, when looking at heavy chemical complexes, it was apparent that the low-grade heat discharged as waste from a refinery could also be used in an adjacent petrochemical plant. There could therefore be a large energy saving potential by utilizing the surplus heat across the sites. Advanced Energy Saving and its Applications in Industry assesses conventional approaches to industrial energy saving and explains and outlines new methods to provide even greater energy saving potential.   Advanced Energy Saving and its Applications in Industry provides a key resource and research tool for all those involved in developing the energy efficiency of industrial processes. Researchers, industry professionals and even students with an interest in green engineering will find the summaries of the conventional and suggested new methods useful when attempting to advance further development within this field