139
1.4.1 C 4 Alkylation
The commercialization of solid acid-based catalysts for C 4 alkylation has revolutionized the process for alkylate production. It has altogether eliminated the safety
and environmental concerns associated with the conventional mineral acid-based
processes. However, another technology that is coming up as a greener alternative
is the ionic liquid (IL)-based C 4 alkylation. Recently, mega oil firms M/s Chevron
and M/s UOP-Honeywell have collaborated and replaced one of their existing alkylation plants using HF as the catalyst with ionic liquid-based catalysts. This is the
best example of retrofitting the new technology with the conventional one. Therefore,
it can be said that the ionic liquid-based technology can be best suited for retrofitting with the conventional C 4 alkylation technologies and easily adapted by companies who want to shift to greener alternatives with minimal capital expenditure.
However, the issues associated with the use of ionic liquids are their cost, recyclability, and handling problems as the most active ionic liquids are moisture sensitive, which leads to the formation of HCl and finally the deactivation of the ionic
liquids. Unless these issues are addressed, the use of ionic liquid-based technology
will lead to high operating costs. Nevertheless, one way for use of the IL-based
technology is retrofitting with the existing HF/H 2 SO 4 -based plants while incurring
minimal capital expenditure. On the other hand, the solid acid-based C4 alkylation
technologies can be adapted by companies which are proposing to set up new plants
for the production of alkylate. The solid acid catalyst-based C 4 alkylation processes
are economically feasible with lower operations cost as compared to the conventional mineral acid and the new ionic liquid-based processes due to the excellent
recyclability of the solid acid catalyst. In future, we can see both the solid acid and
the ionic liquid-based C 4 alkylation technology being adapted by companies, which
eventually will lead to the phasing out of the conventional mineral acid-based
technologies.
Fig. 14 Toluene alkylation with methanol to styrene: Exelus process
Emerging Trends in Solid Acid Catalyst Alkylation Processes
1.4.1 C 4 Alkylation
The commercialization of solid acid-based catalysts for C 4 alkylation has revolutionized the process for alkylate production. It has altogether eliminated the safety
and environmental concerns associated with the conventional mineral acid-based
processes. However, another technology that is coming up as a greener alternative
is the ionic liquid (IL)-based C 4 alkylation. Recently, mega oil firms M/s Chevron
and M/s UOP-Honeywell have collaborated and replaced one of their existing alkylation plants using HF as the catalyst with ionic liquid-based catalysts. This is the
best example of retrofitting the new technology with the conventional one. Therefore,
it can be said that the ionic liquid-based technology can be best suited for retrofitting with the conventional C 4 alkylation technologies and easily adapted by companies who want to shift to greener alternatives with minimal capital expenditure.
However, the issues associated with the use of ionic liquids are their cost, recyclability, and handling problems as the most active ionic liquids are moisture sensitive, which leads to the formation of HCl and finally the deactivation of the ionic
liquids. Unless these issues are addressed, the use of ionic liquid-based technology
will lead to high operating costs. Nevertheless, one way for use of the IL-based
technology is retrofitting with the existing HF/H 2 SO 4 -based plants while incurring
minimal capital expenditure. On the other hand, the solid acid-based C4 alkylation
technologies can be adapted by companies which are proposing to set up new plants
for the production of alkylate. The solid acid catalyst-based C 4 alkylation processes
are economically feasible with lower operations cost as compared to the conventional mineral acid and the new ionic liquid-based processes due to the excellent
recyclability of the solid acid catalyst. In future, we can see both the solid acid and
the ionic liquid-based C 4 alkylation technology being adapted by companies, which
eventually will lead to the phasing out of the conventional mineral acid-based
technologies.
Fig. 14 Toluene alkylation with methanol to styrene: Exelus process
Emerging Trends in Solid Acid Catalyst Alkylation Processes