Process for drying material and dryer for use in the process
AssigneePacific Edge Holdings Pty Ltd
InventorsRoderick Howard Carnegie, Brendon Gerrard Cooper, William John Stevens
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Abstract
A process of drying moisture containing material having a tendency to create dust when dried, said process including the steps of providing said material in a heated chamber having a steam containing atmosphere at a temperature above the dewpoint of the steam, recirculating a hot gas including a portion of the steam through said chamber in order to evaporate moisture from the material to a predetermined level of dryness.
Claims20
A dryer for use in drying moisture containing material comprising aggregates of brown coal having a tendency to create dust when dried, whereby the process minimizes generation of the dust, the process including the steps of:
- providing the material in a heated chamber having a steam containing atmosphere at a temperature above the dewpoint of the steam,
- recirculating a hot gas including a portion of the steam through said chamber in order to evaporate moisture from the material to a predetermined level of dryness, and
- controlling the relative humidity by venting excess steam from the chamber when the steam content exceeds a threshold value,
- wherein the chamber receives and continuously conveys the moisture containing material therethrough;
- the dryer further including
- a heater for heating the chamber to a temperature sufficient to evaporate moisture from the material and generate steam to maintain the steam above its dewpoint;
- an inlet and an outlet through which a recirculating stream of hot gas including a portion of the steam passes into and out of said chamber;
- recirculating means for recirculating the hot gas stream through the chamber;
- and
- a vent which is operable to control the relative humidity in the chamber by releasing a portion of the hot gas stream from the chamber when the concentration of steam in the chamber exceeds a threshold value.
A process for upgrading brown coal including the steps:
- attritioning the brown coal to enable water to be released from the microstructure of the brown coal and thereby producing an admixture of the brown coal and released water;
- forming aggregates of the admixture;
- drying the aggregates to a predetermined level of dryness while minimizing generation of dust by:
- providing said aggregates in a heated chamber having a steam containing atmosphere at a temperature above the dewpoint of the steam, and
- recirculating a hot gas including a portion of the steam through said chamber in order to evaporate moisture from the aggregates to the predetermined level of dryness;
- and
- controlling the relative humidity by venting excess steam from the chamber when the steam content exceeds a threshold value.
A process of drying moisture containing material comprising aggregates of brown coal having a tendency to create dust when dried, whereby said process minimises generation of said dust the process including the steps of:
- preheating a chamber by indirect transfer of heat form a heated fluid;
- introducing a portion of the aggregates of brown coal into the preheated chamber to evaporate moisture therefrom and produce steam;
- recirculating a portion of the steam with a hot gas stream through the chamber in order to attain a temperature above the dewpoint of steam;
- continuing to introduce the aggregates into the chamber having the stream containing atmosphere at a temperature above the dewpoint of the steam;
- continuing to recirculate the hot gas including a portion of the steam through said chamber in order to evaporate moisture from the material to a predetermined level of dryness;
- and
- controlling the relative humidity by venting excess steam from the chamber when the steam content exceeds a threshold value.
Dependencies are inferred from the claim text.