MARPOL waste consists of heavy fuel oil sludge, oil
sludge, used engine lubricating oil, spillages of fuel oil and Diesel fuel,
water used to clean filtration systems, waste from cleaning tanks and
drains, the contents of the bilge tank and sludge tank, etc., which are
produced in ships during sea crossings. Upon reaching port, this waste is
consigned to authorised waste management and treatment companies for its
recovery.
These authorised companies also manage and
treat other hydrocarbons produced by other industrial activities, such as
all types of lubrication oil, contaminated fuel oil and Diesel fuel,
petroleum spirits and their derivatives, and other types of flammable
products that are mixed with MARPOL waste.
Some of the waste is characterised by
containing over 50% water, which must be separated by several processes of
decantation and centrifugation, so that the MARPOL waste
may later be used as a fuel (possibly mixed with fresh heavy fuel oil), in
Diesel engines or in boilers, furnaces, etc.
One of the main problems created
by its use in Diesel engines or in boilers is the high presence solid waste
in the combustion gases produced. These waste products largely arise from fuel oil sludge and oil
sludge from engines. Thus, MARPOL fuel usually contains,
in comparison with heavy fuel oil, high quantities of Calcium
(1,000 – 2,000 ppm, as opposed to 5-10 ppm in heavy fuel oil from a
refinery), Iron (100 - 250 ppm, as opposed to max. 10 ppm
in fuel oil), Ash (0.4 – 0.7%, as opposed to max 0.1%. in
heavy fuel oil), so that these compounds produce incrusted residues to
abnormally high levels in the circuit of gases from combustion
(turbo-compressors, heat exchangers, economisers, etc.) as well as in the
combustion chambers of engine cylinders. In practice, this situation causes
numerous stoppages for cleaning, a low Service
Factor of the installations and increased maintenance
costs.
Tests of additive treatments have
been performed over several
months (more than one year) with additives from "rb bertomeu"
in an installation with Diesel engines running on heavy
Fuel oil derived from recovered MARPOL waste, in an attempt to
reduce, on the one hand, the exceptionally high level of incrusted residues
produced, especially in the gas sections of turbo-compressors and combustion
chambers in cylinders, which entail continual cleaning and overhauls; and
on the other hand, to reduce the frequent and arduous cleaning operations
on fuel separators and fuel filters. The additive employed was of the type "rb
bertomeu" beco F1/ASF and the results obtained,
as reported to us by PORT ECOREL, the Plant consuming MARPOL
, after several months in operation, are described below.
-Reduction in the frequency of
cleaning turbo-compressors: The frequency of cleaning the turbo
has been reduced, using the water injection method, from 5 times per week
to 3 times per week (Reduction of 40%) and in addition the
cleaning operation is more effective because the incrusted residue
is more easily removed. Thus, the time spent on cleaning has also been
reduced.
-Reduction in the time required to
clean fuel Separators: There has been a most noticeable
improvement in the frequency and the time spent on the arduous task of
cleaning the fuel oil separators. The frequency of cleaning had reached an
average of once every ten days, whereas now it has been reduced to
once every thirty days (triple of cleaning TBO).
The time spent on cleaning the separator has been cut down, and the
cleaning operation is easier to carry out, requiring much less
effort. This has led to a significant reduction in maintenance
costs, both for replacement components for the separator and costs
incurred for labour.
-Reduction in the labour required
for cylinder head maintenance: Less time is spent on
reconditioning the injectors, especially in cleaning incrustations off the
injectors and the sleeve to which they adhere. Similarly, it is now easier
to clean the cylinder head.
-Prolonged life for injection
nozzles: There is clear evidence of a significantly prolonged
operational life for injection nozzles, which leads to a reduction in
maintenance costs (yet to be quantified).
-Increased production of
electrical energy and a reduction in costs: All the above factors
mean that annual energy production increases, as fewer maintenance
stoppages are required, and maintenance costs are reduced, thereby
increasing the profitability of the cogeneration plant.
Given that MARPOL waste
also contains Vanadium and Sodium, there
is also a reduction in corrosion at high temperatures caused by sodium
vanadates, in line with the reduction in corrosion obtained when using fuel
oil treated with the same additive. In this case, as the tests are
short-term, and intended merely to verify differences in the accumulation
of residues, measurements were not made of the reduction in corrosion,
which will undoubtedly become apparent in the medium and long term.
For further information on this subject,
please consult the following documents from rb bertomeu
(click on the chosen title):