Air-flow regulation system for a coal gasifier

Patent · Sun Jan 01 00:00:00 EST 1984

OSTI ID:865042

Fasching, George E ^[1]

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1. Morgantown, WV

An improved air-flow regulator for a fixed-bed coal gasifier is provided which allows close air-flow regulation from a compressor source even though the pressure variations are too rapid for a single primary control loop to respond. The improved system includes a primary controller to control a valve in the main (large) air supply line to regulate large slow changes in flow. A secondary controller is used to control a smaller, faster acting valve in a secondary (small) air supply line parallel to the main line valve to regulate rapid cyclic deviations in air flow. A low-pass filter with a time constant of from 20 to 50 seconds couples the output of the secondary controller to the input of the primary controller so that the primary controller only responds to slow changes in the air-flow rate, the faster, cyclic deviations in flow rate sensed and corrected by the secondary controller loop do not reach the primary controller due to the high frequency rejection provided by the filter. This control arrangement provides at least a factor of 5 improvement in air-flow regulation for a coal gasifier in which air is supplied by a reciprocating compressor through a surge tank.

• Research Organization: National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV (United States)
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4453948
• OSTI ID: 865042
• Country of Publication: United States
• Language: English

Related Subjects

air-flow
regulation
coal
gasifier
improved
regulator
fixed-bed
provided
allows
close
compressor
source
pressure
variations
rapid
single
primary
control
loop
respond
controller
valve
main
air
supply
line
regulate
slow
changes
flow
secondary
faster
acting
parallel
cyclic
deviations
low-pass
filter
time
constant
20
50
couples
output
input
responds
rate
sensed
corrected
reach
due
frequency
rejection
arrangement
provides
factor
improvement
supplied
reciprocating
surge
tank
acting valve
fixed-bed coal
line parallel
control arrangement
control loop
arrangement provides
coal gasifier
flow rate
air flow
coal gas
supply line
bed coal
air supply
time constant
pass filter
reciprocating compressor
air-flow regulation
low-pass filter
pressure variations
flow regulator
/48/137/