Method of heating fine-grained solids

• US 4,345,914 A
• Filed: 09/16/1980
• Issued: 08/24/1982
• Est. Priority Date: 08/20/1976
• Status: Expired due to Term

• Current Assignee: Metallgesellschaft AG (GEA Group AG)
• Original Assignee: Metallgesellschaft AG (GEA Group AG)
• Inventors: Rammler, Roland
• Primary Examiner(s): Dees, Carl F.
• Application Number:
  US06/187,856
• Time in Patent Office: 707 Days
• Field of Search: 432/14-16, 432/58, 432/106, 34/10, 34/57 A, 34/57 R, 44/10 H, 44/10 C, 44/10 E, 44/10 J, 44/10 K
• US Class Current: 44/599
• CPC Class Codes: C10B 49/08 in dispersed form
• CPC Class Codes: C10B 57/08 Non-mechanical pretreatment of the charge C10L9/00 takes precedence, e.g. desulfurization
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Abstract

A process for heating fine-grained solids, especially carbonaceous solids such as coke or oil shale, by a process wherein solids are heated to 500° to 920° C. in direct contact with hot gases in a plurality of heating stages, the last of which is a fluidized bed heating process.

Claims

1. A process for heating a fine-grained coal or coke in direct contact with hot combustion gases which comprises feeding said coal or coke and oxygen containing hot gas to a vertical conveyor zone, heating and simultaneously partially combusting said coal or coke and effecting a considerable temperature rise of the coal or coke by the hot combustion gases and pneumatically transporting said coal or coke in said conveyor zone to a collecting zone, the coal or coke being thus heated to a temperature of 400°

-800°

C., causing said coal or coke to flow from said collecting zone to a final heating stage comprising a fluidized bed zone where the coal or coke is partially combusted in contact with oxygen-containing hot fluidization gases and being thus heated to a temperature of 500°

-900°

C., the coal or coke being thus heated in only two heating stages, and using the so-heated coal or coke in a mixture to produce briquettes or pellets.

2. A process according to claim 1 wherein the solids which are heated contain combustible components which are released from said solids as they are heated, the released gases containing combustible components being employed as a fuel for at least one of the heating stages.

3. A process according to claim 1 wherein the gases for the heating stages are fed to said stages from a common combustion chamber wherein said gases are heated.

4. A process according to claim 1 wherein a secondary gas which is air is preheated and is fed to said vertical conveyor line.

5. A process according to claim 1 wherein the fluidized bed process is effected in a fluidized bed furnace into which secondary air is added in the upper half of the height of the fluidized bed but below the upper surface of the components thereof.

6. A process according to claim 1 wherein the lower portion of said collecting vessel comprises a fluidized bed furnace wherein the solids are heated to the final temperature.

7. A process according to claim 1 wherein the fine-grained solids are entrained by the fluidizing gas, and the same are subsequently used with the solids withdrawn therewith from the fluidized bed process.

8. A process according to claim 1 wherein fine-grained solids are entrained by the fluidizing gas and thereafter said gas is separated from the solids which it has entrained and said gas is employed after separation of the withdrawn solids.

9. A process according to claim 1 wherein said fluidized bed process is performed in a fluidized bed furnace comprising a plurality of conduits through which the solids are passed with the fluidizing gas, at least one of the conduits thereof containing a baffle to at least partially retard the flow of the solids in the fluidizing gas.

10. A process according to claim 9 wherein the flow of solids is retarded by a baffle in the shape of a disc, said baffle being spaced a distance from the end point of a feed conduit through which the solids heated in a previous heating stage pass en route to said fluidized bed furnace.