BTU Flowmeters for Gaseous Fuels

Sensors Required
Conventional head-type flowmeter, calorimeter, or wobble index detector plus pressure
and temperature measurements
Process Fluids
Gaseous fuels
Applications
Combustion processes are optimized by measuring and controlling fuel gas flow on
the basis of the heat flow (BTU/h) requirement of the process
BTU Flow Range
From 100 BTU/min to very large heat flow rates; limited only by pipe sizes
Inaccuracy
±1.0 to± 2.0% of full scale, depending on the accuracy of the head type flowmeter used
Costs
for the costs of the different types of calorimeters. The cost of
a general-purpose wobble index detector is $10,000 to $12,000. Explosion-proof
designs cost $5000 to $6000 more. For flow, temperature, and pressure transmitter
costs, refer to Chapters 2, 4, and
5.
Partial List of Suppliers
ABB Process Automation—Analytical Div. (www.abb.com/us)
The Foxboro Co. (www.foxboro.com)
Honeywell Industrial Control (www.honeywell.com/acs/cp)
ICS (www.icsadvent.com)
Thermo Onix Process Analyzers (formerly Fluid Data/Amscor) (www.thermoonix.com).



The heat flow rate provided by the burning of a fuel gas can
be measured by detecting its mass flow rate and multiplying
it by its heating value, which can be detected by wobble index
sensors or calorimeters . The burning
of waste gases from a variety of process sources .
and the accurate control of regular fuel gases made it necessary
to measure their heat flows on line and continuously.
In the past, only the volumetric flow of the fuel gas was
measured, and the heating value and the specific gravity of
the gas were assumed to be constants. This approach is not
acceptable for applications involving the burning of waste
gases, because both their composition and heating values are
variable.
In the past, in hazardous areas, the heating value of fuel
gases could not be continuously measured, so specific gravity
measurements were used to estimate their heating value and
to control the combustion process. Today, continuous and
explosion-proof calorimeters are available for
the measurement of the heating value of any fuel gas. These
optimized combustion controls are automatically adjusted for
variations in either the specific gravity or the heating value
of the fuel gas.


The heat flow rate provided by the burning of a fuel gas can
be measured by detecting its mass flow rate and multiplying
it by its heating value, which can be detected by wobble index
sensors or calorimeters. The burning
of waste gases from a variety of process sources
and the accurate control of regular fuel gases made it necessary
to measure their heat flows on line and continuously.
In the past, only the volumetric flow of the fuel gas was
measured, and the heating value and the specific gravity of
the gas were assumed to be constants. This approach is not
acceptable for applications involving the burning of waste
gases, because both their composition and heating values are
variable.
In the past, in hazardous areas, the heating value of fuel
gases could not be continuously measured, so specific gravity
measurements were used to estimate their heating value and
to control the combustion process. Today, continuous and
explosion-proof calorimeters are availablefor
the measurement of the heating value of any fuel gas. These
optimized combustion controls are automatically adjusted for
variations in either the specific gravity or the heating value
of the fuel gas.