Biofuels and e-fuels as a boost for many engines

Biofuels and e-fuels are important building blocks in the global quest for a sustainable energy future. They are renewable and also promising alternatives to fossil fuels, as they reduce CO₂ emissions by up to 95 percent in comparison. WIKA has been supporting projects in the field of biofuels and e-fuels for many years with customised instrumentation solutions.

The differences between the fuels relate primarily to the individual production processes:

These two reactor types are used to produce biofuels and e-fuels. The model TC96-R Flex-R^® multipoint thermocouple is the first choice for temperature monitoring in fixed-bed reactors (left diagram). Its safety transition (secondary containment) between the reactor and junction box is monitored, depending on the requirements, by pressure gauges, pressure gauges with wireless signal, process transmitters or pressure gauges with electrical output signal (from top to bottom). For use in the catalyst tubes of the Fischer-Tropsch tubesheet reactors (right diagram), the model TC97 miniature multipoint is the ideal solution. In both cases the actual number of measuring points is usually much higher than shown in the diagram.

HVO, HEFA and biomass to liquids (BtL)

The industry distinguishes between biodiesel (FAME = “fatty acid methyl esters”) and renewable diesel such as HVO (“hydrotreated vegetable oil”) and HEFA (“hydroprocessed esters and fatty acids”). In contrast to biodiesel, HVO and HEFA can be used as “drop-in” fuels due to their superior quality, which means directly without having to adapt the engines. Furthermore, the combustion quality is better due to the higher cetane content, as are the cold-flow properties.

HEFA and HVO are typically based on vegetable and used cooking oils, animal fats and tall oil from pulp production. Production includes processes such as hydrotreatment and hydroisomerisation in fixed-bed reactors.

Advanced biofuels can also be produced by gasifying biomass. The resulting syngas is then converted into liquid fuel using the Fischer-Tropsch process. This method, known as “biomass to liquids” (BtL), usually utilises forestry and agricultural waste and residues. Municipal waste can also be used as a feedstock.

E-fuels from CO₂ and hydrogen

E-fuels (or RFNBO = “renewable fuels of non-biological origin”) offer the potential to decarbonise sectors that are difficult to electrify, such as aviation and shipping. Usually, they are also produced using the Fischer-Tropsch process. The input materials in this case are CO₂ from carbon capture processes and hydrogen produced by electrolysis using electricity from solar, wind or hydro energy.

Fischer-Tropsch reactors for e-fuels contain catalyst-filled tubes in which syngas is converted into paraffinic hydrocarbons. After hydrocracking, these enter the distillation process, where they are processed into aviation fuel, for example.

Biofuels and e-fuels: Broad range of instrumentation for the production

A team from WIKA-Gayesco’s field service prepares the installation of model TC96-R Flex-R® multipoint thermocouples in a reactor.

The production of biofuels and e-fuels requires sophisticated measurement instrumentation for process monitoring. This applies in particular to temperature control during exothermic reactions.

In the plants for HVO and HEFA diesel, the high-precision model TC96-R Flex-R^® multipoint thermocouples (multipoints) come into play. There they provide a precise temperature profile in the reactor beds. The choice of material is also decisive for their use. This is because there is a high risk of corrosion in the processes due to the possible presence of free fatty acids, carbon dioxide, water and chlorine in the process media.

The catalyst-filled pipes in the Fischer-Tropsch tubesheet reactors present a technical challenge during installation. The model TC97 multipoint thermocouple sensor in miniature design is ideal for this task. Customers can also take advantage of an installation service for the temperature sensors in the processes mentioned, ensuring optimum installation of the instruments.

Solutions for all measurands

It goes without saying that plant operators can also draw on WIKA’s extensive expertise in additional instrumentation solutions. An example for the know-how regarding processes for biofuels and e-fuels are the bypass level indicators with titanium floats coated with diamond-like carbon (DLC). In addition, there are specific pressure, flow and further temperature measuring instruments and also diaphragm seals, thermowells / protection tubes and valves.

Note
WIKA has also compiled a white paper containing useful information on biofuels and the measuring instruments used for their production. On the WIKA website you will find further information on the mentioned instrument models TC96-R Flex-R^® and TC97. There you can also learn more about WIKA’s sustainability strategy and download a copy of the sustainability report. Should you have any further questions, your contact will gladly help you.

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