optimização da hidrogenação de MAPD no steam cracker da

petroquímica
optimização da hidrogenação
de MAPD no steam cracker
da Repsol Polímeros, Lda.
André A.Vilelas1, José P. Braga2
Process Team, Olefins Plant, Repsol Steam Cracker.
1
[email protected], [email protected]
Abstract
The Repsol Steam Cracker, in Sines, is modelled with the AspenTech PIMS and it was found that the
propylene production was not optimized, i.e. losses of near 18 ton/day.
The C3 hydrogenation reactors were one of the systems to be studied, since typical steam cracker C3 cuts
contain 92% propylene and 4% to 6% methyl acetylene and propadiene (MAPD) which must be removed to
meet propylene and propane product specifications. This hydrogenation gas reaction consists of four adiabatic catalyst beds, in series, of which three beds are used in normal operation. The palladium (0.03% to
0.04%) base catalyst must be selective to the hydrogenation of C3H4 to C3H6.
On this study, it was concluded that the C3 reactors had been operated with a very low selectivity (45%).
Repsol Polímeros Lda has designed and developed a new DMC controller in order to optimize MAPD
reaction conversion and minimize the losses of propylene to propane, due to over hydrogenation. This
controller manipulates the total hydrogen flow rate to the reactors maximizing the propadiene concentration
at the outlet.
The results achieved are outstanding since the propylene production has increased about 5.5 kta, corresponding to 1.3 M€ gain in the plant operation profit.
INTRODUÇÃO
O Complexo Petroquímico de Sines, Repsol
Polímeros, Lda., possui 6 fábricas. São elas
o Steam Cracker, o Butadieno, o ETBE, o
Polietileno de Alta e Baixa Densidade e a
Central Térmica, que produz vapor para os
diferentes consumidores.
No Steam Cracker são produzidos etileno
e propileno polymer grade por cracking
térmico (pirólise) de vários hidrocarbonetos como etano, propano, butano e nafta
num processo licenciado pela Linde AG.
Os rendimentos de cracking destas duas
olefinas, etileno e propileno, rondam os
30-35% e 15-20%, respectivamente. Os
co-produtos são uma corrente C4 rica em
1,3-butadieno, uma gasolina C6-C8 rica
em aromáticos e fuelóleo.
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