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Title: Ash bed level control system for a fixed-bed coal gasifier

Abstract

An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level. In order to avoid grate binding, the controller provides a short base operating duration timemore » each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.« less

Inventors:
 [1];  [2]
  1. (Morgantown, WV)
  2. (Fairmont, WV)
Issue Date:
Research Org.:
National Energy Technology Laboratory, Pittsburgh, PA, and Morgantown, WV
OSTI Identifier:
865043
Patent Number(s):
4453949
Assignee:
United States of America as represented by United States (Washington, DC) NETL
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
ash; bed; level; control; fixed-bed; coal; gasifier; provided; incorporates; meter; automatically; selected; signal; updated; cycle; stirrer; travels; extent; derived; temperature; measurements; thermocouples; carried; passes; fire; zone; immediately; compared; threshold; determine; below; counter; incremented; decremented; accordingly; registered; count; preset; counted; clock; rate; grate; drive; activated; rotate; assembly; supporting; period; equal; maintain; avoid; binding; controller; provides; base; operating; duration; time; drops; exceeds; means; notify; operator; fixed-bed coal; level control; level signal; threshold level; bed level; temperature measurements; coal gasifier; coal gas; ash bed; bed coal; temperature measurement; selected level; ash level; automatically control; assembly supporting; drops below; level meter; selected threshold; clock rate; grate assembly; controller provides; temperature measure; bed stirrer; /48/422/700/

Citation Formats

Fasching, George E., and Rotunda, John R. Ash bed level control system for a fixed-bed coal gasifier. United States: N. p., 1984. Web.
Fasching, George E., & Rotunda, John R. Ash bed level control system for a fixed-bed coal gasifier. United States.
Fasching, George E., and Rotunda, John R. Sun . "Ash bed level control system for a fixed-bed coal gasifier". United States. https://www.osti.gov/servlets/purl/865043.
@article{osti_865043,
title = {Ash bed level control system for a fixed-bed coal gasifier},
author = {Fasching, George E. and Rotunda, John R.},
abstractNote = {An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level. In order to avoid grate binding, the controller provides a short base operating duration time each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1984},
month = {1}
}

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