Apr-2022

The role of biofuels in the energy transition

Overcoming the challenges of coprocessing renewables.

MARCIO WAGNER DA SILVA
Petrobras

Article Summary

The increasing need to reduce the environmental impact of fossil fuels has led to a trend of decarbonisation of the energy matrix at a global level, creating a new challenge for the crude oil production and processing chain.

In this scenario, one of the available alternatives is raising the participation of renewable fuels and higher use of renewable raw materials in the feed of crude oil to refineries. This has led some refining technology licensors to dedicate efforts to develop processes for this purpose.

The adoption of synergies between fossil fuels and renewables in the downstream industry depends on the refiner’s market, the availability of renewable raw materials as well as the capacity of the installed refining hardware to process renewable streams.
Despite these limitations, it is important to remember that renewables are already contributing to the reduction of demand for fossil raw material. According to data from the International Energy Agency (IEA), the COVID-19 pandemic caused the first contraction in the biofuels market in two decades (see Figure 1).

Despite this contraction in 2020, stricter regulations and policy pressure will drive a fast recovery and expansion in biofuels demand (see Figure 2).

Considering these trends, it is possible to estimate the impact of biofuels in the crude oil refining industry; the coprocessing of renewable raw material in traditional crude oil refineries can be an attractive decarbonisation strategy. After the pandemic, some refiners decided to convert refining assets to process renewable raw material, reinforcing this trend in the new scenario of the downstream industry.

Biofuels production in Brazil
Brazil has a long tradition in biofuels production. In 1975, due to the petroleum crisis, the Brazilian authorities launched an alternative fuel programme called Proálcool, where the main intention was to support the development of ethanol from sugar cane as an automobile fuel substitute for gasoline, to reduce external dependence in the Brazilian energy matrix.

Brazil has a long tradition in biofuels production. In 1975, due to the petroleum crisis, the Brazilian authorities launched an alternative fuel programme called Proálcool, where the main intention was to support the development of ethanol from sugar cane as an automobile fuel substitute for gasoline, to reduce external dependence in the Brazilian energy matrix.

According to the Brazilian Petroleum Agency (ANP), in 2019 Brazilian ethanol production reached 35.3 million m3 as volumes of anhydrous and hydrated ethanol. This production reveals consistent growth in production over the years. Figure 3 shows the ethanol production profile over recent years in the Brazilian market.

Based on data from Figure 3, ethanol production grew at an average annual rate of 2.3%. Considering only anhydrous ethanol, annual growth is even more impressive at 2.60% in the 2010-2019 period. By law, gasoline sold in Brazil must contain 27% by volume anhydrous ethanol which is applied to improve gasoline quality (octane boosting) and to ensure the participation of renewable fuels in the energy matrix. Hydrated ethanol is sold in gas stations as fuel for automobiles. According to data from ANP, in 2019 Brazilian production of hydrated ethanol reached 24.9 million m3 with average annual growth of 2.1% over the 2010-2019 period.

Brazil is a great consumer of transportation fuels. The main driver of the economy is diesel because of the country’s dimensions and the transport infrastructure which relies on roads. Total production of diesel in the Brazilian market reached close to 41 million m3 in 2019. By law, diesel commercialised in Brazil territory must contain 12% by volume biodiesel and the intention of the government is to raise this to 15% in 2023. Figure 4 shows the evolution of Brazilian biodiesel production between 2010 and 2019 in million m3.

The main raw material used to produce biodiesel in Brazil is soybean oil with close to 68% of total production, followed by animal fat at 11%.

While the blending of anhydrous ethanol with gasoline and biodiesel with diesel represents a strategy to produce cleaner fuels, it is not the only strategy being applied by refiners aiming to reduce the environmental footprint of transportation fuels.

An important trend in the downstream energy transition is the coprocessing of renewable raw material in crude oil refineries. This strategy involves feeding the renewable raw material directly to the refining process, which is a more challenging decarbonisation strategy.

Renewables coprocessing in crude oil refineries
The adoption of synergies between fossil fuels and renewables in the downstream industry depends on the refiner’s market, in particular the availability of renewable raw materials as well as the capacity of the installed refining hardware to process renewable streams.

The adoption of synergies between fossil fuels and renewables in the downstream industry depends on the refiner’s market, in particular the availability of renewable raw materials as well as the capacity of the installed refining hardware to process renewable streams.

One of the most common processing routes is the utilisation of vegetable or animal oils in the feedstock of conversion or treating units to produce high quality fuels and petrochemicals. The renewable raw material can be directly processed together with fossil streams in units including fluid catalytic cracking (FCC) to produce transportation fuels and olefins.

Renewable streams also can be applied as feed to hydrotreating units, to produce high quality diesel and jet fuel.

In the petrochemical sector, the production of intermediates has adopted renewable processing routes such as ethanol to ethylene.

Some companies have applied ethylene production via ethanol dehydration since 2010 and some technology licensors have developed processing routes also dedicated to producing ethylene from ethanol.

Despite its advantages, renewables coprocessing presents some technological challenges. Renewable streams contain high levels of unsaturation and oxygen, resulting in high exotherms and hydrogen consumption. This requires higher capacity for heat removal from hydrotreating reactors to avoid damage to catalysts. The main chemical reactions associated with renewable streams in hydrotreating are:

R-CH=CH2 + H2 à R-CH2-CH3 (olefins saturation)
R-OH + H2 à R-H + H2O (hydrodeoxygenation)