Ash level meter for a fixed-bed coal gasifier

Patent · Sun Jan 01 00:00:00 EST 1984

OSTI ID:865138

Fasching, George E ^[1]

---

1. Morgantown, WV

An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by an appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500.degree. F.), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage.

• 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 4466747
• OSTI ID: 865138
• Country of Publication: United States
• Language: English

Related Subjects

ash
level
meter
fixed-bed
coal
gasifier
provided
utilizes
temperature
profile
monitor
bed
stirrer
travels
extent
modified
installing
thermocouples
measure
stirring
cycle
measurement
signals
transmitted
electronic
signal
process
fm
telemetry
processing
analog
position
transducer
disposed
compute
vertical
location
zone
upper
boundary
circuit
determines
fraction
total
time
stirrer-derived
below
selected
set
multiplies
average
result
appropriate
constant
adds
volt
processor
corresponds
30
inch
span
individual
counters
store
clock
counts
representative
500
degree
duration
corresponding
travel
inputs
disconnected
period
stopped
eliminating
corruption
stoppage
signal level
bed temperature
fixed-bed coal
measurement signals
temperature profile
bed level
coal gasifier
coal gas
time duration
ash bed
bed coal
temperature measurement
vertical position
ash level
electronic signal
circuit determines
temperature signal
level meter
position signal
signal process
cycle time
vertical location
measurement signal
temperature measure
bed stirrer
/374/48/73/