Decarbonisation Technology May 2026 Issue

was changed to heavy fuel oil. In 1973, naphtha became the main feedstock. The modern Tai Po Towngas plant commenced operation in 1986, producing hydrogen-rich town gas on four Catalytic Rich Gas (CRG) trains. Each train of the Tai Po Towngas facility has a CRG reactor (pre-reformer) and a tubular steam methane reformer at its heart. The reformate is rich in hydrogen and CO 2 and contains less than 3% carbon monoxide (CO). However, this CO 2 concentration is too high, so CO 2 is captured from the reformate and is vented to the atmosphere. This CO 2 could easily be dried and liquefied for utilisation as commercial CO2 . Singapore also runs on town gas. City Energy’s Senoko Gasworks supplies 0.9 million commercial and domestic offtakers who use town gas for heating and cooking. Like Hong Kong’s Tai Po facility, it is fuelled by a mixture of naphtha from local refineries and imported liquid natural gas (LNG).  Natural gas processing : Natural gas processing is like crude oil refining: it converts raw gas into a usable commercial product. When natural gas rises from the reservoir, the methane is laden with light hydrocarbons, known as natural gas liquids (NGLs) and CO 2 . Hydrogen sulphide is often present too. Removal of CO 2 is essential for operational reasons to generate natural gas, which is transmitted to industrial and commercial users by pipeline or liquefied to make LNG. The capital investment and operational costs of CO 2 removal are borne by the natural gas processing. However, in most cases, the CO 2 is vented to the atmosphere. Two notable exceptions are the Sleipner West and Snow White CCS schemes, which are owned and operated by Equinor in the North Sea. CO 2 from natural gas processing has also been identified as a low-cost source of merchant CO2 . In Australia, Air Liquide and BOC recover CO 2 from the Longford Gas Conditioning plant east of Melbourne. Air Liquide started up a 60,000 tpy liquefier to produce food and beverage- grade merchant CO 2 there in 2021. BOC followed with a tonne-per-year plant in 2024. The amount of CO 2 that is captured in the acid gas removal facility depends on the sweetness of the gas. Longford is designed to process sour

Maximum loading for various HPC-based solvents

Physical solvents, eg. methanol, follow Henry’s law

Maximum loading for various amine- based solvents

Henry’s law

HPC

Amine-based

Solvent loading, Mol CO/Mol solvent (logarithmic scale) * CO partial pressure = CO molar concentration x stream pressure

rich in CO 2 , with water vapour being the main additional component. The water vapour can be separated by cooling the gas stream to condense the moisture. The incondensable CO 2 gas can then be fed to a liquefier. In the Middle East, where the petrochemical industry is thriving due to low feedstock costs, ethylene oxide production is the most common source of low-cost CO 2 . Gulf Cryo, an industrial gases company in the Gulf Cooperation Council (GCC) region, obtains CO 2 from one of Equate Petrochemical Company’s EO plants in Kuwait’s Shuaiba Industrial Area. A pipeline of several hundred metres transfers raw CO 2 from the stripper column on the EO plant to the Gulf Cryo site, where it is dried, liquefied, and purified to produce 55,000 tonnes of commercial CO 2 per year. Gulf Cryo implemented a similar scheme at the EO plant operated by Petro Rabigh in Saudi Arabia. This plant came on stream in 2023 with an annual capacity of 100,000 tonnes of commercial CO 2 . Sourcing CO 2 as a byproduct from EO facilities avoids the use of a natural gas burner to generate commercial CO 2 and minimises fossil fuel consumption to support decarbonisation.  Town gas production : Hong Kong has been using town gas for heating, cooking, and industrial applications since 1864. At that time, coal gasification was the source of town gas. In 1967, the feedstock for town gas production Figure 3 CO 2 capture technology selection – rules of thumb for initial screening of liquid solvent systems