초록 ▼

A method and apparatus for drying of low-rank coals, such as lignite, where the coal is passed through a sealed vessel in a plurality of heated fluidized beds with fluidization effected by superheated steam flowing counter-current to the flow of coal. A composite steam is exhausted from the sealed v

A method and apparatus for drying of low-rank coals, such as lignite, where the coal is passed through a sealed vessel in a plurality of heated fluidized beds with fluidization effected by superheated steam flowing counter-current to the flow of coal. A composite steam is exhausted from the sealed vessel, partially condensed, to remove an amount of water about equal to that removed from the coal, and the steam reheated and recycled to the sealed vessel. The heating of the fluidized beds is by means of heat exchange tubes passing through the beds, with a fluid, such as methanol, heated for flow through the tubes, collected and in a cooled state used in the partial condenser, and then compressed to reheat the same for reuse in the heat exchange tubes.

대표청구항 ▼

An apparatus for drying low-rank coals containing interstitial water, comprising: a sealed vessel containing means for forming a plurality of successive fluidized beds of solids therein, having means for passing low-rank coal solids thereto at one end and means for removing said low-rank coal solids

An apparatus for drying low-rank coals containing interstitial water, comprising: a sealed vessel containing means for forming a plurality of successive fluidized beds of solids therein, having means for passing low-rank coal solids thereto at one end and means for removing said low-rank coal solids therefrom at the other end after passage therethrough; heat exchange tubes extending into said sealed vessel at the location of each of said fluidized beds; steam injector means at said other end of the sealed vessel for charging steam into said vessel for passage therethrough countercurrent to the flow of low-rank coal solids to fluidize the same in each of said plurality of successive fluidized beds, and remove interstitial water therefrom to form a composite steam flow; means for exhausting said composite steam flow from said one end of the sealed vessel; means for partially condensing said composite steam flow, to which said composite steam flow is passed after exhaustion from said vessel, so as to remove a supply of condensed water therefrom substantially equal to the water removed from the low-rank coal in said sealed vessel; means for heating said steam flow after removal of said condensed water and returning the heated steam to the sealed vessel through said steam injector means; means for passing a secondary heated fluid through said heat exchange tubes, to effect heat exchange between said fluid and said low-rank coal, whereby the low-rank coal is heated and the fluid cooled and condensed; means for passing said cooled fluid, after said heat exchange, to said means for partially condensing said composite steam flow to partially condense the same; and means for compressing said cooled fluid, after passage through the means for partially condensing said composite steam, to heat the same and return the heated fluid to said heat exchange tubes.