Page 107 - vol5_n2

237 IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 2
E. M. R. FAIRBAIRN | T. P. DE PAULA | G. C. CORDEIRO | B. B. AMERICANO | R. D. TOLEDO FILHO
the set of cement/ash municipalities with greater transport distance
between themselves, being, apparently, the less favorable scenario
for the emissions reduction. The greatest possible distances be-
tween the various pairs of cement/sugar cane municipalities in São
Paulo occur between Ribeirão Pires, east of the state, with a produc-
tion of 631 kt of cement and the cane producer municipalities of the
west region of São Paulo. Faraway 724 km of Ribeirão Pires, the
city of Teodoro Sampaio is the furthest from that town and presented
a production of 897.3 kt of sugar cane, followed by Andradina and
Pereira Barreto, with distances of 719 km and 711 km and produc-
tions of 2,200 and 1,300 kt of sugar cane, respectively.
The determination of the most favorable scenario for CDM de-
ployment within the State of São Paulo would involve all possible
combinations of additives producers and receivers as well as the
various combinations of quantity of ash transported. The most fa-
vorable set of combinations would be one that minimized the final
average distance of ash transportation. This analysis has been
addressed in recent studies of Fairbairn et al . [21], where the use
of computational algorithms for transport distance minimization
and for optimization of the ash distribution among the factories
was successful.
7. Results
7.1 Scenario 1: municipalities of greater
production of ash and cement
For this scenario, the calculation of emission reductions resulting
from the implementation of CDM is done between the two munici-
palities of greater production of the state of São Paulo: Jaboticabal
and Sorocaba.
The two cities are separated by a road distance of 318 km. Con-
sidering the share of ash on the total cement produced as 7.5%
(cement type A with 0% ash and cement type B with 15% ash) and
the cement production of Sorocaba, 209.475 kt of ash are required
for this scenario, which is easily supplied by the ash production
of Jaboticabal, estimated at 790.769 kt. Table 1 summarizes the
results obtained by applying the ACM 0005 methodology for emis-
sions calculating in scenario 1.
7.2 Scenario 2: most unfavorable ash transport
distances
The scenario 2 estimates the worst-case situation for CDM project
implementation regarding emissions from ash transport, the main
emission arising from the use of this additive. The cement produc-
tion of Ribeirão Pires requires, for the proposed ratio of replace-
ment, 47.3 kt of ash. Whereas Teodoro Sampaio produces 22.4
kt of additive, there is a deficit of -24.9 kt of ash to supply the total
production of cement. This way, was included the production of
55 kt of ash from Andradina, which presents the second largest
transport distance, keeping the analysis conservative and supply-
ing the project with surpluses of ash. It is worth to point out that
the economic and financial feasibility of ash transportation is not
part of the scope of this analysis, which is restricted to the criteria
defined by the ACM 0005 methodology.
For this scenario, the calculation of fugitive emissions for ash trans-
port, called Leakage, and the calculation of emission reductions
are separated into two equations: one for the transport of 22.4 kt of
ash from Teodoro Sampaio to Ribeirão Pires, and another to 24.9
kt transported from Andradina to the same municipality. The sum
of the emission reductions of both alternatives make up the final
emission reduction of the scenario 2. The results obtained for this
scenario are shown in table 2.
8. Discussion
In both scenarios analyzed was possible to obtain a positive bal-
ance of emissions reduction, revealing that there are real perspec-
tives of CDM project implementation. Even for the scenario 2, the
most unfavorable due to the largest transport distances, the aver-
age CO2 emissions per ton of ash (L add_trans) is almost 100 times
smaller than the CO2 emissions per ton of clinker ( 〖BE/PE〗clinker).
The results obtained for CO2 emissions per ton of cement on the
Baseline of both scenarios are lower than the world average, es-
timated at 1.0 tons of CO2 per ton of cement [2]. This low rate of
emissions is due to the fact that the energy matrix that underlies
the Brazilian power grid is hydroelectric in nature, which emission
factors are considerably smaller than those of other energy sourc-
es more common in other countries. This fact is demonstrated by
the low values of the terms 〖BE〗ele_grid_clnk and 〖PE〗ele_grid_clnk.
Emissions relating to calcination reaction and the burning of fossil
fuels represent almost all emissions of Baseline for both scenarios.
However, among the factories considered in this study, there is a
considerable discrepancy in relation to the use of fossil fuels in the
production, denoting sensitive technological differences. Factories
in the municipality of Ribeirão Pires did not register emissions re-
lating to the combustion of fuels, unlike factories of Sorocaba.
In both scenarios, the total amount of SCBA generated was able
to supply the demand of factories, generating surpluses of ash.
It is possible to imagine a series of alternatives for destination of
this surplus as: (1) involve more cement factories and sugar cane
mills in the project; (2) increase the fraction of ash on cement in
the analyzed scenarios through technological improvements in the
ash preparation and (3) increase the production of cement in the
analyzed scenarios. All these alternatives raised could promote
greater emission reductions.
A more detailed study of the feasibility of implementing this type of
CDM project should consider a financial and economic analysis,
incorporating ash staging and obtaining costs, transport costs, the
revenue obtained by selling the CER, besides several variables of
the local market, but that are outside of the purposes of this work.
However, it is noteworthy that, in the case of a residue to be dis-
posed, the ash has a obtaining cost virtually nil, although its cost
tends to increase with the increasing in demand. In relation to the
revenue obtained by selling the CER, the amount paid per ton of
CO2 has historically varied between € 15 and € 35.
9. Conclusions
Initiatives to reduce environmental impacts in the industry as
the reduction of greenhouse gas emission and re-use of waste
generated are strategic, both politically and economically, and
configure themselves as issues of great relevance in the cur-
rent international scenario. In this sense, the use of SCBA as
an additive in the manufacture of cement goes towards the
global yearning for environmentally correct production technolo-
gies. The capacity of improvement in mechanical performance