Between the two variants of fluidized bed combustion (FBC)
technology, the type of CFBC (circulating fluidized bed combustion) is more
widely used for power generation than BFBC (bubbling fluidized bed combustion).
That is because the level of efficiency is higher, the use of large capacity
and the amount of flue gas produced is less. Stoichiometric air requirements for
CFBC (1.1 - 1.2) are less than BFBC (1.2 - 1.3), this also results in less flue
gas produced at CFBC compared to BFBC. The main difference between CFBC and
BFBC is that there is a circulation of the use of bed material in CFBC and CFBC
using air velocity greater than BFBC.
The fuel used for CFBC has a smaller particle size compared
to BFBC so it will require higher preparation / pretreatment costs. This is one
of the drawbacks of CFBC. The usual preparation is foreign material control and
size reduction. Fuels used like coal must be cleaned of a number of impurities
such as metals. Magnetic separator is a equipment commonly used to separate the
impurities of these metals. The metals that pollute the coal apart from
damaging the screen on the crusher (if using a hammer mill type crusher) it is
also possible to cover the perforated plate at the bottom of the fluidized bed
furnace. The closure of these pores causes disruption of air circulation which
will certainly affect the output of the unit.
PKS or palm kernel shell is a biomass fuel that are widely
available in Indonesia and have characteristics close to wood pellets. The PKS
can be used for CFBC fuel both for cofiring and fullfiring (100% PKS).
Regarding the preparation or pre-treatment of fuel before it is fed or used in
CFBC, it also needs to be done for PKS. PKS measuring 2-5 cm need to be cleaned
from a number of impurities and size reduction before use. In cofiring, when
equipments for coal preparation can also be used for PKS, it means no new line
is needed for that. But if it can't, a new line needs to be made. Some power plants
in Japan even use 100% PKS as fuel with the CFBC technology and especially in
the framework of environmental and climate change solutions supported by the
government.
 |
| CFBC biomass power plants in Japan with 49 MW capacity which has been operating since 2015 with PKS |
The use of fluidized bed combustion (FBC) technology has
actually been carried out since the 1960s, which at that time was mainly used
to treat municipal and industrial waste. At present it is estimated that more
than 300 FBC units are installed and operating throughout the world. PKS as
palm oil mill solid waste (CPO mill) is available in abundance in Indonesia
which is estimated to reach more than 10 million tons / year and in Malaysia is
estimated to be more than 5 million tons / year. This is so that the use of PKS
on FBC is very possible because the volume and availability is sufficient.
Economic factors are especially limiting the use of the PKS, although in terms
of the environment and climate change, it is strongly supported. The location
of the palm oil mills which is in the middle of the plantation commonly in very
remote locations also makes logistical costs expensive so it affects the
selling price of the PKS.
No comments:
Post a Comment