Energy Technology &
Control’s ETC6009
combustion controller
enables bio and off gases
to be burnt independently
or blended with a base
fuel in proportion to the
amount available at a
given time. An external 4-20mA
signal determines the proportion of
bio or off gas that is used as part of
the modulation rate.

If there was 50% bio or off gas
available and heating demand was
75%, then 50% would be bio or off
gas and 25% base fuel. If demand for
heat was 40%, all of this would be
made up of the bio or off gas. ETC
says it is not possible to fire some bio
and off gases independently due to
their low calorific values. ETC6009
ensures that a minimum amount of
base fuel is always fired on profiles
when these gases are used.