Patent IL-130546-A (IL)
Title: Oil shale fluidized bed
IPC: F22B31/00
Filed: 1999-06-18
Abstract: A fluidized bed combustion system having a thermodynamic steam cycle and a flue gas flow path acting in cooperative association therebetween for effecting the combustion of fuel therein including oil shale and the generation of steam thereby, said fluidized bed combustion system comprising: (a) a furnace volume defined by a plurality of waterwall tubes integral to the thermodynamic steam cycle and embodying therewithin a lower segment thereof for the combustion of oil shale therein generating upwardly mobile flue gases thereby and an upper segment thereof in fluid flow relation with said lower segment; (b) a fluidized bed ash cooler operative as a heat exchanger in fluid communication with said furnace volume; (c) fuel supply means in fluid communication with said furnace volume for delivering oil shale thereto for combustion therein; (d) a deentrainment zone disposed in said lower segment of the furnace volume for deentraining particulate matter generated from said combustion and entrained within said upwardly mobile flue gases such that subtantially all of said particulate matter is retained within the furnace volume, said furnace volume including a fluidized bed 1150 י" ב בסיון התשס" ב - May 23, 2002 composed of bed solids and underbed air inlet means connected to said lower segment of the furnace volume and operative to inject upwardly flowing fluidizing air thereinto at a velocity of at least 10 feet per second, and the deentrainment zone being disposed above said fludized bed in which some of said bed solids rise and subsequently return downwardly to said fluidized bed and said fluidized bed having a height below which said bed solids do not rise into said deentrainment zone; (e) a backpass volume defined by a plurality of backpass wall tubes integral to the thermodynamic steam cycle, said backpass volume connected in fluid flow relation with the furnace volume and said furnace volume being operated such that a fraction of said particulate matter does not exit furnace volume via said backpass volume and another fraction of said particulate matter exits said furnace volume via said backpass volume such that the percentage of the particulate matter which does not exit said furnace volume via said backpass volume is at least ninety-five percent of the total quantity of the particulate matter and the particulate matter which has exited said furnance volume via said backpass volume is subjected to electrostatically based separation before a selected one of additional separation by cyclonic based separation and no additional separation by cyclonic based separation, said backpass volume including means disposed therein for preheating air, said means having operatively connected thereto air inlet means and fluizing air outlet means, said fluidizing air outlet means in fluid flow relation with said underbed air inlet means; (f) a plurality of circulatory fluid flow paths integral to the thermodynamic steam cycle and operative to conduct the flow of steam or water therethrough, said plurality of circulatory fluid flow paths including a steam drum for separating steam from water, at least one circulatory fluid flow path integral to the thermodynamic steam cycle and operative as a water-evaporative steam loop including said waterwall tubes, means for conveying water from the steam drum thereto, means for conveying a mixture of water and steam therefrom to the steam drum, a circulatory fluid flow path integral to the thermodynamic steam cycle and operative as a water-superheated steam loop including at least one superheat heat exchange means, means for conveying steam from the steam drum thereto, a high pressure turbine, means for conveying steam from the at least one superheat heat exchange means thereto, a condenser, means for conveying steam from the high pressure turbine thereto, a fluid conveying means, means for conveying steam from the condenser thereto, at least one economizer heat exchange means, means for conve