METHOD AND SYSTEM FOR DRYING PARTICULATE MATERIAL

摘要

A system for drying moist, particulate material includes a steam dryer having a container containing superheated steam. Upper and lower heat exchangers, with a channel extending through them, are located in the container. An impeller generates a flow of steam upward in the container outside the heat exchangers and downward through the channel. Guide plates around the heat exchangers guide the moist, particulate material from an inlet in the lower part of the container around the heat exchangers, subjecting the material to the flow of the steam, thereby drying the material. A steam conduit supplies a primary steam flow to the lower heat exchanger, which condenses the primary steam flow into a flow of hot water that is directed to a flow generator that generates a fluid flow from the hot water flow. A fluid conduit leads the fluid flow to the upper heat exchanger.

主权项

1. A method of drying moist particulate material, said method comprising:
(a) providing a supplier of pressurized steam, and a steam dryer for drying said moist particulate material, said steam dryer comprising:
(i) a closed container maintaining an atmosphere comprising superheated steam at an elevated pressure, said closed container comprising a lower part and an upper part;(ii) a heat exchanger assembly located inside said closed container and comprising a channel for allowing said superheated steam to be transported from inside said upper part to inside said lower part, said heat exchanger assembly comprising a first heat exchanger and a second heat exchanger for heating said superheated steam, said first heat exchanger being positioned above said second heat exchanger and said channel going through said first and second heat exchangers; and(iii) a plurality of guide plates positioned upright and circumferentially around said heat exchanger assembly; (b) supplying a primary flow of steam from said supplier to said second heat exchanger for heating said second heat exchanger and condensing said primary flow of steam within said second heat exchanger into a flow of condensed hot water; (c) discharging said flow of condensed hot water from said second heat exchanger; (d) generating a first flow of fluid from said flow of condensed hot water; (e) leading said first flow of fluid to said first heat exchanger for heating said first heat exchanger; (f) generating a flow of said superheated steam going upward on the outside of said heat exchanger assembly to the inside of said upper part and downward through said channel; (g) feeding said moist particulate material into said lower part of said closed container; (h) guiding said moist particulate material by means of said plurality of guide plates along a path around said heat exchanger assembly carried by said flow of said superheated steam, thereby subjecting said moist particulate material to said flow of said superheated steam for converting said moist particulate material into dry particulate material; and (i) removing said dry particulate material from said closed container.