Method and apparatus for drying materials in fixed beds |
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| 申请号 | US43543374 | 申请日 | 1974-01-22 | 公开(公告)号 | US3894344A | 公开(公告)日 | 1975-07-15 |
| 申请人 | DRAVO CORP; | 发明人 | MALCOLM DONALD B; | ||||
| 摘要 | Condensation which occurs in a bed of ore on a traveling grate for sintering, or a bed of agglomerates, such as pellets, on a traveling grate in the process of heat-hardening them, which occurs when drying and preheating air first flows through the bed is reduced if not eliminated by conserving heat contained in the fines or imparted to the fines during their preparation, such as grinding, or from the drying of filter cake comprised of such fines, and even further augmenting this heat to increase the temperature of the fines or make up for loss which occurs before the fines or agglomerates are loaded onto the grate whereby the charge on the grate is already warm before the current of drying air flows through it. | ||||||
| 权利要求 | 1. In the process of drying a moist, heated particulate material in a fixed bed for further processing wherein the material becomes heated during the preparation of the material for such drying and processing, the step which comprises conserving the heat and moisture contained in the material, after its preparation until it is deposited in a fixed bed to be then dried by transferring the material from the apparatus in which it is prepared to the fixed bed through an enclosure which conserves heat in the material and also prevents adiabatic cooling resulting from evaporation of moisture therefrom through contact with a drying atmosphere during such transfer. 2. In the process defined in claim 1, the further step of supplying additional heat and moisture to the material while it is being so transferred through said enclosure. 3. The process defined in claim 2 wherein the additional heat so supplied is more than sufficient to offset loss of heat and moisture from the material which would otherwise occur but is also sufficient to increase the temperature thereof while avoiding drying of the material. 4. In the process defined in claim 1, the further step of forming the material into agglomerates while it is being so transferred through the enclosure. 5. In the process defined in claim 1, the further step of rolling the warm moisture particulate material into pellets in the course of being transferred through the enclosure. 6. The method defined in claim 1 in which the heat acquired in the preparation of the material results from grinding basic raw material into fines. 7. The method defined in claim 1 in which the heat is acquired in the preparation of the material by the removal of at least some of the moisture in the material in a heated dryer. 8. The method defined in claim 1 in which a heated moist atmosphere is maintained in the enclosure at above atmospheric pressure to prevent ingress of surrounding air. 9. In a mineral processing apparatus for drying heated moist particles wherein there is provided a means for preparing the particles to be processed, the operation of which discharges the particles in a heated moist condition and wherein there is a grate to which the moist particles are to be delivered and on which they are dried in a fixed bed with means for circulating heated air through the material on the grate, the invention comprising: a. a transfer system for continuously transferring the particles from said preparing means to the grate having a receiving end positioned to receive the moist heated particles from said preparing means and a discharge end arranged to discharge the material directly onto the grate, a heat-conserving enclosure for the transfer system extending from end to end of said system, and b. means for maintaining a controlled moist atmosphere in the enclosure to protect the material against adiabatic cooling during its transfer from the receiving end of the system to the discharge end. 10. The invention defined in claim 9 in which said transfer system particles into formed agglomerates which are then discharged onto the grate. 11. The invention defined in claim 10 in which said means for agglomerating the fines comprises a pelletiziing disk. 12. The invention defined in claim 9 wherein means is provided for introducing combined heated air and moisture into said enclosure. 13. The invention defined in claim 9 wherein said transfer system comprises within the enclosure between the inlet and discharge ends: a. a pelletizer; b. means for delivering heated moist particles from the receiving end to the pelletizer; c. a feeder at the discharge end of the enclosure for delivering pellets onto the grate; d. means for receiving pellets from the pelletizer and transferring them to the feeder, and e. means for supplying heat and moisture to the enclosure for heating the particles and the pellets and retarding evaporation of moisture. 14. The invention defined in claim 13 wherein said last-named means comprises means for maintaining the atmosphere in the enclosure above atmospheric pressure. |
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