Flex refineries could help in the transition to a low-carbon economy

In an event held at FAPESP headquarters, researchers defended the use of the Brazilian refinery park to co-process raw materials of fossil and biomass origin.

By Karina Toledo

Agência FAPESP – Utilization of the Brazilian refinery park to simultaneously process raw materials of fossil and biomass origin – transforming the units into flex refinery units – could lead to a smooth transition to a low-carbon economy and, at the same time, help to meet Brazil’s growing energy demand.

Professor Ofélia de Queiroz Fernandes Araújo, a faculty member at Universidade Federal do Rio de Janeiro’s School of Chemistry (UFRJ –EQ), defended the proposal during the 2nd Finnish-Brazilian Workshop on Biomass Conversion. The Network of Excellence in Biomass and Renewable Energy (NOBRE) held the event on October 31 at FAPESP’s headquarters.

According to Araújo, who along with José Luiz de Medeiros coordinates the Laboratory of Hydrorefining, Process Engineering and Applied Thermodynamics (H2CIN) at UFRJ, the concept of a flex refinery is being introduced to NOBRE. The group is also currently simulating hybrid stages such as the biomass gasification process.

“Oil is a liquid with millions of different molecules that are fractured and converted in refineries to create gasoline, diesel and a series of other derivatives. Nothing is thrown away in refineries because processes have been developed to deal with even the heaviest and most recalcitrant residues (the bottom of the barrel). Therefore, there are also conditions to deal with another nonconventional raw material, which is biomass,” says Araújo.

Because they are abundant in Brazil and are not competing with food production, agroindustrial residues are the ideal raw material for supplying to hybrid refineries, according to Araújo’s evaluation.

Through a chemical process known as gasification, it would be possible to transform this material into synthesis gas – a mixture of gases used in several synthesis reactions of the products of the chemical industry. This mixture is composed principally of hydrogen and carbon monoxide and can be directly burned to generate energy and vapor (cogeneration) or serve as a raw material to obtain methanol, urea, ammonia (fertilizer) and olefins (used in the manufacture of some types of plastic and synthetic rubber).

“With the help of catalyzers and the ideal pressure and temperature conditions inside a reactor, it is possible to transform gas synthesis into several chemical products of economic interest. Through a process known as Fischer-Tropsch, it is even possible to obtain diesel and gasoline, transforming what was residue into gold,” affirmed Araújo.

The equipment necessary to process biomass – the gasifier – exists in several oil refineries in the world and is currently considered a mature technology. According to Araújo, for approximately 20 years, the use of gasifiers has been restricted to the realm of research, but there are currently experiments being conducted on an industrial scale.

“Bolstered by the approval of the largest oil and natural gas reserves in the pre-salt layer of the Brazilian maritime platform, the federal government made heavy investments in the expansion of the refinery park. What we are proposing is to use this infrastructure to co-process raw material of fossil origin and biomass. Sharing the installed infrastructure would reduce the cost of processing represented by refineries exclusively dedicated to biomass, making a smooth transition to an environmentally sustainable economy,” she opined.

This measure would be necessary, according to Araújo, because no truly low-carbon technology would manage to penetrate the mass market in the short term. Although several studies are underway in Brazil, principally with sugarcane bagasse, biomass still has relatively low economic competitiveness as a raw material compared to petroleum and natural gas.

“Biomass is increasingly distributed geographically and is perishable. You cannot accumulate the raw material over three or four weeks and then transport it to a hub for processing. This creates a large logistical problem. Natural gas, on the other hand, can be compressed and distributed through pipelines,” commented Araújo.

Although exploration of oil and natural gas in the pre-salt layer involves several challenges – such as the high extraction cost at more than 5,000 meters of depth and transportation to the continent – working with biomass is currently even more expensive.

“Natural gas in the pre-salt layer has a high level of CO2 – it reaches 80% in the case of the Jupiter well, according to National Petroleum Agency data. This is an impurity that must be processed. Petrobras does not consider emitting this CO2, but this makes the process more expensive. Therefore, this natural gas will not have the same cost as gas sold in the United States,” Araújo assessed.

In this already discouraging scenario, adds the researcher, a new competitor that will tend be a stronger rival than biomass emerges: shale gas – a type of natural gas extracted from rocky formations that has begun to be explored in Brazil.

Extraction of shale gas requires fracturing of rocks through the injection of large quantities of water, sand and chemical products into the subsoil, which raises major questions about its environmental impacts. “It is a new competitor that comes at a very low cost. It is not environmentally sustainable and will not have a green seal. But will society stop buying it?” she pondered. “I don’t think so.”

Although she recognizes a direct relationship between economic development, increased energy consumption and carbon dioxide emissions, Araújo said it is necessary to identify “cutting edge technology” that will allow some time gains so that scientific research can change the productive paradigms and so that Brazil can definitively adopt a green economy without foregoing the generation of wealth.

“We don’t want a cold economy, but we also don’t want to heat up the planet any further. We need to find shortcuts to the new pathways that are being built,” she affirmed.

NOBRE

At the beginning of 2012, FAPESP and the Academy of Finland (AKA) signed a research cooperation agreement.

Later the same year, a Finnish delegation led by Prime Minister Jyrki Kataine visited Brazil and announced the creation of NOBRE, bringing together researchers from the two countries with the mission of funding partnerships and projects in the area of biomass and renewable energy.

“It is an excellence network and, in addition to researchers, we are involving companies and governmental sectors. We got leaders in the area from the two countries and put all of them together to debate in a neutral environment and create projects,” explained Pedro Fardim, a faculty member at Abo Akademi University and coordinator of NOBRE in Finland.

The first initiative proposed by the group is the creation of an international doctoral program focused on biomass and renewable energy, which will be coordinated by NOBRE and conducted in partnership with leading Brazilian and Finnish universities. The course, which is still in the planning stages, will be offered to 10 students from each country who will spend half their time in Brazil and half in Finland.

“This will have a very large multiplying effect on the number of joint research projects,” commented Universidade de São Paulo professor Cláudio Augusto Oller do Nascimento, coordinator of NOBRE in Brazil.