Global Sulphuric Acid for Petroleum Refining Market Outlook, 2031

In refining, sulphuric acid's most important job is as the catalyst in alkylation units, which combine light olefins such as propylene and butylenes with isobutane to make alkylate, a clean, high-octane gasoline blending component with almost no sulphur, aromatics or olefins. Alkylate typically makes up around 10% to 15% of the US gasoline pool and has become more valuable as gasoline sulphur limits fell to 10 parts per million under US Tier 3 and Euro standards and as octane requirements rose. Roughly half of global alkylation capacity uses sulphuric acid, with the rest using hydrofluoric acid or newer ionic liquid and solid-acid technologies. Sulphuric acid alkylation consumes acid in large volumes because the catalyst is diluted by water and acid-soluble oils, with commonly cited consumption of around 15 to 20 pounds of acid per barrel of alkylate. Spent acid is sent to regeneration plants, where it is thermally decomposed and reconverted into fresh acid, creating a closed loop between refineries and regenerators. Smaller amounts of acid are used in refinery water treatment, neutralisation of caustic streams, treatment of lubricant base stocks and some specialty processes. Leading technology licensors include Elessent Clean Technologies with STRATCO and the MECS regeneration process, Exxon's stirred autorefrigerated process and Honeywell UOP, while regeneration services are provided by Veolia and refinery-integrated units.

Safety regulation is reshaping refinery acid choices. Hydrofluoric acid can form toxic ground-hugging clouds if released, and the June 2019 fire and explosion at the Philadelphia Energy Solutions refinery, which involved its HF alkylation unit, intensified scrutiny. In March 2024 the US EPA finalised its Safer Communities by Chemical Accident Prevention rule, requiring refineries with HF alkylation units to evaluate safer technology alternatives, and several refiners have converted or are considering converting to sulphuric acid or ionic liquid alkylation, such as Chevron's ISOALKY unit at Salt Lake City started in 2021. These shifts support sulphuric acid demand, since a conversion can add tens of thousands of tonnes of annual acid consumption. Refiners also face raw material risks: acid prices more than doubled in some regions in spring 2026 when the Strait of Hormuz closure disrupted sulphur exports and China banned acid exports from 1 May, although refiners with closed-loop regeneration contracts were partly protected because their spent acid is recycled. Refining itself is shifting, with closures in Europe and California, new capacity in India, the Middle East, China and Africa, and rising gasoline quality standards in emerging markets, all of which shape where alkylation and acid demand grow.

Drivers Demand for Clean, High-Octane Gasoline Stricter gasoline sulphur, aromatic, benzene and vapour pressure limits and higher octane requirements increase the value of alkylate, encouraging refiners to build or expand alkylation units. Emerging markets adopting Euro 5 and Euro 6 equivalent fuel standards are adding alkylation capacity.
Safety-Driven Shift from Hydrofluoric Acid Concerns about the toxicity of hydrofluoric acid, highlighted by incidents such as the 2019 Philadelphia refinery explosion and the EPA's 2024 safer technology requirements, encourage conversions from HF alkylation to sulphuric acid or other technologies, adding acid demand.

Challenges Gasoline Demand Outlook and Refinery Closures Electric vehicles, efficiency gains and refinery closures in Europe, California and Australia may reduce long-term gasoline demand, limiting alkylation growth in mature markets. Refinery margins fluctuate, affecting investment.
Acid Consumption Costs and Logistics Sulphuric acid alkylation consumes large volumes of acid that must be delivered fresh and returned as spent acid, requiring reliable regeneration capacity and safe transport. Acid and sulphur price spikes, as in 2026, raise operating costs, and regeneration plants are capital intensive.

Trends Alkylation Unit Conversions and New Technologies Refiners are evaluating conversions of HF units to sulphuric acid, ionic liquid or solid-acid alkylation, and licensors offer process improvements that reduce acid consumption per barrel, such as better mixing and contactor designs.
On-Site and Regional Acid Regeneration Refiners and service providers are building on-site or nearby spent acid regeneration plants to reduce transport, secure supply and improve emissions performance, often integrated with sulphur recovery units that provide SO₂ feed.




Alkylation accounts for the overwhelming majority of sulphuric acid consumption in petroleum refining because sulphuric acid alkylation units consume large volumes of acid continuously as catalyst, with spent acid regenerated and returned in a closed loop. Alkylation is the dominant use of sulphuric acid in refineries. In a sulphuric acid alkylation unit, olefins and isobutane are mixed with concentrated acid of around 98% to 99% strength at low temperatures, typically between 4°C and 10°C, in contactors or autorefrigerated reactors, producing alkylate with research octane numbers commonly around 94 to 98. The acid gradually becomes diluted with water and acid-soluble oils and is withdrawn as spent acid at around 88% to 90% strength, requiring continuous fresh acid make-up. A typical unit producing 10,000 to 20,000 barrels of alkylate a day therefore consumes hundreds of tonnes of acid a day, making alkylation one of the largest single industrial users of acid. Spent acid regeneration, through thermal decomposition at around 1,000°C to SO₂ followed by conversion back to fresh acid, closes the loop, and many refineries contract with regeneration plants nearby or operate their own units. Water and wastewater treatment in refineries uses acid for pH control and cooling water treatment. Neutralisation of spent caustic from treating units uses acid. Treatment of lubricant base oils and waxes with acid, once common, has largely been replaced by hydrotreating but persists in some older refineries. Acid is used in some specialty processes, including production of petroleum sulphonates and certain chemical treatments. Sulphur recovery units in refineries produce elemental sulphur and, in some cases, feed captive acid plants or regeneration units with SO₂-rich gas, linking refinery sulphur management and acid supply. Overall acid intensity therefore depends mainly on alkylation unit size, feed quality and operating discipline at each refinery.

Sulphuric acid alkylation accounts for roughly half of global alkylation capacity because it avoids the toxic release risks of hydrofluoric acid and is well proven, while HF, ionic liquid and solid-acid technologies make up the rest. Sulphuric acid alkylation, using technologies such as Elessent's STRATCO effluent refrigerated process and ExxonMobil's stirred autorefrigerated process, accounts for roughly half of global alkylation capacity and is the preferred choice for new units in many regions because concentrated sulphuric acid does not form toxic vapour clouds when released. Its main drawbacks are high acid consumption and the need for regeneration infrastructure. Hydrofluoric acid alkylation, licensed historically by Phillips and UOP, uses far less acid because HF is regenerated within the unit, and it remains widespread in the United States and other markets, but safety concerns and regulation have stopped most new HF construction and are prompting conversions. Ionic liquid alkylation, such as Chevron and Honeywell UOP's ISOALKY technology commercialised at Salt Lake City in 2021, and composite ionic liquid technology used in China, offer reduced hazards and lower catalyst consumption. Solid-acid alkylation, including technologies such as K-SAAT and AlkyClean, eliminates liquid acid but has seen limited commercial adoption. When a refinery converts an HF unit to sulphuric acid, annual acid demand at the site can rise by tens of thousands of tonnes, requiring new regeneration and transport arrangements. Technology choice depends on safety regulations, local acid and regeneration availability, capital cost, community concerns and the refinery's existing configuration. Licensors also offer revamps that increase sulphuric acid units' capacity and reduce acid consumption per barrel through improved mixing, reactor design and feed pretreatment that removes contaminants such as dienes and oxygenates. Feed pretreatment that removes contaminants can cut acid consumption per barrel by a meaningful margin and extend unit run lengths.

Spent acid regeneration supplies most of the fresh acid used in refinery alkylation because closed-loop recycling reduces raw material needs and waste, while virgin acid from sulphur burners and smelters provides make-up volumes and backup supply. Spent acid regeneration plants, also called sulphuric acid regeneration units, receive spent acid from alkylation units, decompose it in a furnace to SO₂, water and carbon dioxide, clean the gas and convert the SO₂ back into fresh concentrated acid, which is returned to the refinery. In the United States, regeneration capacity is concentrated along the Gulf Coast, in California and in the Midwest near refining clusters, and services are offered under long-term tolling or supply contracts. Regeneration allows refiners to avoid disposing of spent acid, which is hazardous waste, and reduces the need to buy virgin acid, insulating them partly from merchant acid price swings such as the spike of 2026. Some refiners operate on-site regeneration units integrated with sulphur recovery, using hydrogen sulphide or sulphur from refinery gas as additional feed to make up losses. Virgin acid from sulphur-burning plants and smelters supplies make-up volumes, start-up fills and backup when regeneration plants are down, and its cost is influenced by sulphur prices and regional supply. Transport between refineries and regeneration plants is typically by rail tank car, truck or pipeline for adjacent sites, and the logistics chain must handle both fresh and spent acid safely. Regeneration plants must meet strict SO₂ and particulate emission limits and have invested in scrubbing and monitoring. The reliability of regeneration capacity is a key factor in refiners' decisions to choose or expand sulphuric acid alkylation, and new regeneration investments often accompany HF conversions or new alkylation units in emerging markets. Proximity between refineries and regenerators is therefore a key factor in acid logistics costs.

Large integrated and independent refiners with gasoline-oriented configurations account for most sulphuric acid use in refining because they operate fluid catalytic crackers and alkylation units that turn light olefins into high-octane blending components. Gasoline-oriented refineries with fluid catalytic cracking units, which produce the propylene and butylenes used as alkylation feed, account for nearly all refinery sulphuric acid consumption. The United States has the world's largest alkylation capacity, reflecting its large gasoline market and FCC-heavy refining system, with refiners such as Marathon Petroleum, Valero, Phillips 66, ExxonMobil, Chevron, PBF Energy, HF Sinclair and Citgo operating sulphuric and HF alkylation units. Europe's refiners, more diesel-oriented, have less alkylation capacity, and several European refineries have closed or are converting to biofuels or terminals. China has expanded alkylation capacity rapidly to meet its China VI gasoline standards, using both sulphuric acid and ionic liquid technologies, and India's refiners, including Reliance, Indian Oil, Bharat Petroleum and Hindustan Petroleum, have added alkylation to produce cleaner gasoline. Middle Eastern refiners, including Saudi Aramco and ADNOC, have built alkylation units at new complexes. Latin American refiners in Mexico and Brazil and new African refineries such as Dangote in Nigeria include or plan alkylation capacity. Petrochemical complexes with olefin streams sometimes operate alkylation units. Refiners' acid consumption depends on unit size, feed quality and operating practices, and best-performing units consume significantly less acid per barrel than average. Refinery closures in California, Europe and Australia reduce acid demand locally, while new capacity in Asia, the Middle East and Africa shifts demand geographically. Safety regulators, insurers and local communities influence refiners' technology choices, especially near populated areas. Alkylation unit turnarounds, usually every four to six years, create periodic spikes in acid deliveries and regeneration activity at individual sites.

North America is the largest consumer of sulphuric acid in petroleum refining because the United States has the world's largest alkylation capacity and gasoline market, while Asia-Pacific and the Middle East are growing as new refineries add alkylation units. North America dominates, with US refineries operating the largest share of global alkylation capacity, extensive spent acid regeneration infrastructure along the Gulf Coast, in California and in the Midwest, and regulatory pressure from the EPA's March 2024 safer technology requirements encouraging HF-to-sulphuric acid conversions; acid prices on the US Gulf Coast more than doubled in spring 2026, though regeneration contracts limited the impact on many refiners. Asia-Pacific is a fast-growing region, as China expanded alkylation to meet China VI gasoline standards, India's refiners added alkylation and acid regeneration, and South Korea, Japan, Singapore and Southeast Asia operate alkylation units. Europe has smaller alkylation capacity and faces refinery closures and conversions. The Middle East has added alkylation at new refining complexes in Saudi Arabia, the UAE and Kuwait and is a major sulphur source, but the 2026 war disrupted operations and exports. Latin America, including Mexico, Brazil and Colombia, and Africa, including Nigeria's Dangote refinery, are adding cleaner fuel capacity that includes alkylation.


• March 2026 – Hormuz closure disrupts Gulf refining and sulphur exports: The closure of the Strait of Hormuz disrupted Gulf refineries and sulphur exports, affecting acid supply chains for refiners worldwide.
• May 2026 – China bans sulphuric acid exports: China's export ban, combined with the Hormuz disruption, pushed merchant acid prices sharply higher, raising make-up acid costs for refiners without full regeneration coverage.
• March 2024 – US EPA finalizes safer technology requirements for HF alkylation: The EPA's Safer Communities by Chemical Accident Prevention rule required refineries with HF alkylation units to conduct safer technology and alternatives analyses.


Considered in this report
• Historic Year: 2020
• Base Year: 2025
• Estimated Year: 2026
• Forecast Year: 2031

Aspects covered in this report
• Global Sulphuric Acid for Petroleum Refining Market with its value and forecast along with its segments
• Various drivers and challenges
• Ongoing trends and developments
• Top profiled companies
• Strategic recommendation

By Application
• Alkylation
• Water and Wastewater Treatment
• Spent Caustic Neutralisation
• Lubricant and Wax Treatment
• Other Refinery Uses

By Alkylation Technology
• Sulphuric Acid Alkylation
• HF Alkylation
• Ionic Liquid Alkylation
• Solid-Acid Alkylation

By Acid Source
• Spent Acid Regeneration
• Virgin Acid from Sulphur Burning
• Smelter Acid
• On-Site Regeneration Units

By Refinery Type
• Gasoline-Oriented FCC Refineries
• Integrated Refining and Petrochemical Complexes
• Independent Refiners
• National Oil Company Refineries