Researchers regenerate deactivated catalyst in methanol-to-olefins process

January 04, 2021

MTO process, which was first commercialized in 2010, is a catalytic process converting methanol, which is typically made from coal, natural gas, biomass, and CO2, over SAPO-34 zeolite catalyst. It's becoming one of the main streams for producing light olefins, including ethylene and propylene, from non-oil resources.

One of the major challenges in MTO is the rapid deactivation of zeolite catalyst due to the coke deposition.

In industrial practices, a fluidized bed reactor-regenerator configuration is normally used in order to maintain the continuous operation, in which air or oxygen is usually input to burn off the deposited coke to restore the catalyst activity in the regenerator. This involves the transformation of coke species to CO2, with a substantial fraction of carbon resource being converted to low-value greenhouse gas.

A research group led by Prof. YE Mao and Prof. LIU Zhongmin from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences regenerated deactivated catalyst in industrially important methanol-to-olefins (MTO) process by directly transforming the coke deposited on the zeolite catalyst to active intermediates rather than burning off to carbon oxide.

This work was published in Nature Communications on Jan. 4.

It was previously shown that MTO follows the hydrocarbon pool mechanism, i.e. the light olefins are favorably formed with the participation of active intermediate species, or called hydrocarbon pool species (HCPs), during the reaction. The HCPs will evolve into coke species that deactivate catalyst.

By using the density functional theory (DFT) calculations and multiple spectroscopy techniques, this team showed that naphthalenic cations, amongst HCPs, were highly stable within SAPO-34 zeolites at high temperature, and steam cracking could directionally transform the coke species in SAPO-34 zeolites to naphthalenic species at high temperature.

This technology not only recovers the catalyst activity but also promotes the formation of light olefins owing to the synergic effect imposed by naphthalenic species.

Furthermore, the researchers verified this technology in the fluidized bed reactor-regenerator pilot plant in DICP with industrial-alike continuous operations, achieving an unexpectedly high light olefins selectivity of 85% in MTO reaction and 88% valuable CO and H2 with negligible CO2 in regeneration.

This technology opens a new venue to control the selectivity of products via regeneration in industrial catalytic processes.
-end-


Dalian Institute of Chemical Physics, Chinese Academy Sciences

Related Carbon Articles from Brightsurf:

The biggest trees capture the most carbon: Large trees dominate carbon storage in forests
A recent study examining carbon storage in Pacific Northwest forests demonstrated that although large-diameter trees (21 inches) only comprised 3% of total stems, they accounted for 42% of the total aboveground carbon storage.

Carbon storage from the lab
Researchers at the University of Freiburg established the world's largest collection of moss species for the peat industry and science

Carbon-carbon covalent bonds far more flexible than presumed
A Hokkaido University research group has successfully demonstrated that carbon-carbon (C-C) covalent bonds expand and contract flexibly in response to light and heat.

Metal wires of carbon complete toolbox for carbon-based computers
Carbon-based computers have the potential to be a lot faster and much more energy efficient than silicon-based computers, but 2D graphene and carbon nanotubes have proved challenging to turn into the elements needed to construct transistor circuits.

Cascades with carbon dioxide
Carbon dioxide (CO(2)) is not just an undesirable greenhouse gas, it is also an interesting source of raw materials that are valuable and can be recycled sustainably.

Two-dimensional carbon networks
Lithium-ion batteries usually contain graphitic carbons as anode materials. Scientists have investigated the carbonic nanoweb graphdiyne as a novel two-dimensional carbon network for its suitability in battery applications.

Can wood construction transform cities from carbon source to carbon vault?
A new study by researchers and architects at Yale and the Potsdam Institute for Climate Impact Research predicts that a transition to timber-based wood products in the construction of new housing, buildings, and infrastructure would not only offset enormous amounts of carbon emissions related to concrete and steel production -- it could turn the world's cities into a vast carbon sink.

Investigation of oceanic 'black carbon' uncovers mystery in global carbon cycle
An unexpected finding published today in Nature Communications challenges a long-held assumption about the origin of oceanic black coal, and introduces a tantalizing new mystery: If oceanic black carbon is significantly different from the black carbon found in rivers, where did it come from?

First fully rechargeable carbon dioxide battery with carbon neutrality
Researchers at the University of Illinois at Chicago are the first to show that lithium-carbon dioxide batteries can be designed to operate in a fully rechargeable manner, and they have successfully tested a lithium-carbon dioxide battery prototype running up to 500 consecutive cycles of charge/recharge processes.

How and when was carbon distributed in the Earth?
A magma ocean existing during the core formation is thought to have been highly depleted in carbon due to its high-siderophile (iron loving) behavior.

Read More: Carbon News and Carbon Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.