Thriving in the era of decarbonisation
Published by Poppy Clements,
Editorial Assistant
Hydrocarbon Engineering,
As the world looks towards meeting ambitious carbon-neutrality goals, major energy players are working to replace crude oil with renewable feedstock within refineries. This article will look at the role that Howden plays in enabling initiatives such as this, and will detail a specific case study whereby the company worked with Shell on a major clean fuels project, providing compression solutions for hydrotreatment and sulfur recovery processes.
Case study
In 2021, Howden secured a contract to work on the Shell Energy and Chemicals Park in Rotterdam, the Netherlands. This project holds strategic importance for Shell as it strives to become a net zero emissions entity by 2050. Additionally, European directives mandate increased use of renewable energy in transportation fuels, including sustainable aviation fuels (SAFs) and renewable diesel. As such, the company is aiming to transform its refineries to process renewable feedstock, such as vegetable oils – namely soybean, rapeseed and palm – as well as non-edible waste oils used in cooking.
Howden’s role was to provide equipment for both the hydrotreatment process of the feedstock, utilising reciprocating compressor products, and the sulfur recovery process, utilising SG Turbo compressors. The two companies collaborated closely from the early stages of the project in order to optimise the equipment design and ensure its successful integration into the site.
Compressor in the renewable fuel process
Processing biofeeds for hydrotreated vegetable oil (HVO) presents a new set of challenges for reciprocating compressors. The renewable organic material reacts with hydrogen at an elevated temperature and pressure in a catalytic reactor, making the role of the compressor paramount.
The HVO production process typically consists of two key steps: hydrotreating and hydroisomerisation. The first stage requires a reciprocating compressor for acid gas recirculation (pressure swing adsorption [PSA] discharge back to reactor inlet). This compressor faces a highly corrosive duty due to the acid gas composition of the discharge, which includes hydrogen, sulfur, carbon dioxide and water.
Hydrogen make-up gas is typically introduced in the second processing step of hydroisomerisation, which operates at a higher pressure. Within this process, there is also a requirement for a second compressor to handle the high recycle gas flow rate.
These two very different compression duties were combined into a single reciprocating compressor from Howden, integrating multiple dedicated cylinders and controls. This new solution optimises premium space, reduces total cost of ownership (TCO), and increases energy efficiency.
Expectations related to process variations (pressure, temperature, capacity flow control), fluctuations (suction/ discharge) and compressor operations (operating hours per year/number of starts and stops per day) were validated by the engineering team at an early stage so that the final design stage of the compressor was reached faster. Based on the compressor design and duty, a mean time between maintenance (MTBM) was defined so that the available time was guaranteed.
The sulfur recovery process − whether via the traditional Claus reaction or alternative bioreaction method − is an important part of the refining process. The acidic hydrogen sulfide (H2S) content of the gas stream is removed and recovered to its valuable elemental form: sulfur.
This article was originally published in the October 2023 issue of Hydrocarbon Engineering magazine. To read the full article, sign in or register for a free subscription.
Written by Oliver MacSorley, Howden, a Chart industries company.
Read the article online at: https://www.hydrocarbonengineering.com/special-reports/11102023/thriving-in-the-era-of-decarbonisation/
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