| Fluid Catalytic Cracking (FCC) | Fluidized zeolite cracking catalyst | USY or REUSY zeolite dispersed in a silica–alumina matrix | Converts heavy gas oils into gasoline, liquefied petroleum gas, light olefins and other valuable products. | Vacuum gas oil, atmospheric residue blends, metals, nitrogen and elevated carbon residue. | High activityGood fluidizationAttrition resistanceSelective cracking | Matrix engineering, zeolite stabilization, bottoms-cracking formulations, metals-tolerant systems and additive packages for gasoline, propylene or dry-gas optimization. |
| FCC Additives | Propylene-selective additive | ZSM-5-type zeolite in a catalytic matrix | Increases light olefin production, particularly propylene, by selectively cracking gasoline-range molecules. | Refineries seeking higher propylene yield from FCC units or improved flexibility between gasoline and petrochemical products. | Olefin selectivityHydrothermal stabilityControlled activity | Standalone or co-injected additive systems, dosage optimization and compatibility with the base FCC catalyst inventory. |
| FCC Additives | SOx-reduction additive | Metal oxide-based oxygen-transfer chemistry, commonly containing cerium or related promoters | Transfers sulfur oxides from FCC regenerator flue gas back into the cracking cycle for removal in the reactor section. | High-sulfur feeds and environmental limits on sulfur oxide emissions. | SOx captureRegenerator compatibilityLow impact on cracking | Regenerator-focused formulation, sulfur-transfer optimization and integration with refinery emissions-control systems. |
| Hydrotreating | Distillate hydrodesulfurization catalyst | Cobalt–molybdenum or nickel–molybdenum sulfide phases on alumina | Removes sulfur, nitrogen and selected contaminants while hydrogenating olefins and improving product stability. | Naphtha, kerosene, diesel and other middle-distillate streams containing sulfur and nitrogen compounds. | High HDS activityLong cycle lifeLow pressure dropRegenerability | Pore-size tailoring, high-dispersion active metals, grading systems and catalyst loading designs for pressure-drop and heat-management control. |
| Residue Hydrotreating | High-metals residue hydrotreating catalyst | Nickel–molybdenum or cobalt–molybdenum sulfides on macroporous alumina or mixed-oxide supports | Reduces sulfur, nitrogen, metals and Conradson carbon while protecting downstream units. | Atmospheric residue, vacuum residue and heavy feeds containing nickel, vanadium, asphaltenes and high microcarbon residue. | Large pore volumeMetals uptakeGuard-bed protectionResistance to deactivation | Multi-bed grading, demetallization guard catalysts, pore architecture control and staged replacement strategies. |
| Hydrocracking | Dual-function hydrocracking catalyst | Nickel–tungsten or nickel–molybdenum hydrogenation metals combined with acidic zeolite or amorphous silica–alumina | Converts heavy feedstocks into high-quality diesel, kerosene, naphtha and lubricant-range products. | Vacuum gas oil and heavy distillates requiring deep conversion, sulfur removal and improved product quality. | High conversionHydrogenation activityProduct selectivityNitrogen tolerance | Single-stage and two-stage catalyst systems, acidity adjustment, conversion-selective formulations and catalyst grading for temperature control. |
| Naphtha Reforming | Reforming catalyst | Platinum with rhenium or other promoters on chlorided alumina | Raises octane by converting paraffins and naphthenes into aromatics and hydrogen. | Low-octane naphtha streams; feed contaminants such as sulfur, nitrogen and water must be tightly controlled. | High octane yieldHydrogen productionCoking resistanceStable dispersion | Continuous, semi-regenerative and cyclic reforming catalyst systems; optimized metal dispersion, chloride management and regeneration protocols. |
| Isomerization | Light naphtha isomerization catalyst | Chlorinated alumina with platinum, or sulfated zirconia-based systems | Converts normal paraffins into branched isomers to increase gasoline octane without forming significant aromatics. | C5/C6 light naphtha with strict requirements for sulfur, water and oxygenate removal. | High isomerate octaneLow benzene formationMild operating conditions | Feed-purification guidance, chloride-management systems, hydrogen-assisted operation and catalyst options for different refinery configurations. |
| Alkylation | Acid alkylation catalyst system | Hydrofluoric acid or sulfuric acid, depending on the process design | Combines isobutane with light olefins to produce high-octane, low-sulfur alkylate blending component. | Refinery C3/C4 olefin streams and isobutane; requires careful acid, water and contaminant management. | High octane alkylateLow vapor pressureLow sulfur | Acid-strength management, corrosion-control practices, contaminant removal and process-safety systems associated with acid handling. |
| Hydrogen Production | Steam methane reforming catalyst | Nickel supported on calcium-aluminate or related refractory materials | Converts natural gas or light hydrocarbons with steam into synthesis gas for hydrogen production. | Hydrogen demand from hydrotreating and hydrocracking units; feed sulfur must be removed upstream. | High reforming activityThermal stabilityCoking resistanceMechanical strength | Top-fired and side-fired reformer compatibility, shaped catalyst geometries, low pressure-drop designs and catalyst loading recommendations. |
| Hydrogen Purification | Water-gas shift catalyst | Iron–chromium oxide for high-temperature shift; copper–zinc oxide–alumina for low-temperature shift | Converts carbon monoxide and steam into additional hydrogen and carbon dioxide. | Synthesis gas from steam reforming or partial oxidation, with operating conditions selected by shift stage. | CO conversionThermal stabilitySulfur sensitivity control | High- and low-temperature shift configurations, guard-bed recommendations and optimized catalyst loading for heat and mass transfer. |
| Sulfur Recovery | Claus sulfur-recovery catalyst | Activated alumina or titanium dioxide-based catalyst | Converts hydrogen sulfide and sulfur-containing compounds into elemental sulfur. | Acid gas from amine treating and sour-water stripping units. | High sulfur conversionHydrolysis activityWater toleranceLong service life | Hydrolysis catalysts, titanium-enhanced formulations, guard catalysts for contaminants and staged Claus reactor catalyst systems. |
| Tail-Gas Treatment | Selective oxidation or tail-gas hydrogenation catalyst | Alumina-supported cobalt–molybdenum, nickel–molybdenum or oxidation-promoted metal systems | Improves sulfur recovery by converting residual sulfur compounds before final incineration or further treatment. | Claus tail gas containing hydrogen sulfide, sulfur vapor, sulfur dioxide and carbonyl sulfide. | Deep sulfur conversionLow-temperature activityPoison resistance | Tail-gas hydrogenation, selective oxidation, carbonyl sulfide hydrolysis and integrated sulfur-emissions reduction solutions. |