Feb-2021

A case for renewable hydrogen (TIA)

Processing renewable feedstocks is more complex than processing non-renewables.

Mie Bjørn-Rosager
Haldor Topsoe

Article Summary

For one thing, it requires extra hydrogen which, if produced traditionally from natural gas, can have a significant impact on greenhouse gas (GHG) emissions from the whole process. However, by switching to renewable hydrogen, refiners can significantly reduce their greenhouse gas emissions and expand the range of renewable feedstocks to choose from, and several customers have chosen to do that already.

Legislation and choice of feedstock
The trend to apply legislation to reduce emissions is advancing globally, with potentially far-reaching repercussions for the refinery industry. In the US, the Renewable Fuel Standard 2 requires refineries to blend 36 billion gallons of renewable fuel into the country’s total transportation fuels consumption by 2022. In the European Union, new units producing biofuels will have 65% GHG emission savings targets on biofuels from 2021.

To significantly reduce the emissions and meet the renewable fuels standards, refineries need to look at the whole value chain of the feedstocks they process. Even before the hydrotreating process, the renewable feedstock will already have a CO2 footprint connected to the use of fertiliser, harvesting, extraction, and transportation.

This means that many renewable feedstocks carry too large a CO2 footprint to meet the renewable fuels standards, leaving refiners with smaller selection of feedstocks that grow increasingly expensive due to the higher demand (see Figure 1). A way to mitigate the situation is to incorporate the use of renewable hydrogen in the process.
 
Renewable hydrogen
Hydrotreating renewable feedstocks containing oxygen and unsaturated compounds requires significant consumption of hydrogen. Traditionally, fossil feedstocks such as natural gas have been used to produce this hydrogen, having a significant impact on GHG emissions from the whole process. But Haldor Topsoe’s H2bridge may eliminate that need as it enables the production of hydrogen from renewable LPG and/or naphtha. It does so by recycling the off-gases from the hydrotreating process thereby producing hydrogen from renewable off-gasses. In other words, H2bridge provides a circular system that fully integrates hydrogen and hydrotreatment. By switching to renewable hydrogen, refiners can thus reduce substantial amounts of GHG emissions, depending on the feedstocks, the hydrogen requirement, and the off-gas production. Several refineries have already chosen this solution in order to meet the Low Carbon Fuel Standard (LCFS), or RED II. One refiner, for example, realised that integrating a HydroFlex unit with an H2bridge unit enabled it to choose from a broader feedstock slate, which improved the economic feasibility of the project (see Figure 2). Whatever the case, renewable hydrogen will have an impact on profitability, as refiners will be able to surpass the minimum GHG savings requirements.

Renewable hydrogen is a natural step on the way towards green hydrogen. It can make a significant difference here and now.

This short case study originally appeared in PTQ's Technology In Action feature - Q1 2021 issue.

For more information: MBJR@topsoe.com