Mazut 100 & 180 CST Fuel Oil: Specs, Uses & Export Markets

Mazut 100 and Mazut 180 CST remain the workhorse heavy fuel oil grades for shore based power generation and industrial boilers across Asia the Middle East and the Mediterranean. The two grades share high sulfur content and similar density ranges but diverge sharply on viscosity pour point and the heating infrastructure they demand. Choosing the wrong grade forces expensive retrofits or leaves burners running outside their design envelope increasing emissions and maintenance costs.

This guide breaks down the specification sheets heating calculations burner compatibility and regulatory frameworks that govern trade in these fuels. You will learn how to size preheat systems for each grade navigate the IMO 2020 sulfur cap and GCC GSO 2195 requirements classify shipments under HS 2710.19.06 and secure the certificates of conformity that customs authorities in Saudi Arabia the UAE and India require before cargo discharge.

Mazut 100 vs 180 CST Fuel Oil Quick Comparison

Viscosity and Density Parameters

Mazut 100 exhibits a kinematic viscosity of 100 centistokes at 50 degrees Celsius while Mazut 180 CST measures 180 centistokes at the same reference temperature. The higher viscosity of the 180 grade demands more aggressive preheating to reach the 15 to 20 centistokes target required for pressure jet atomization. Density for both grades typically falls between 0.96 and 0.99 kilograms per liter at 15 degrees Celsius though the 180 grade often trends toward the upper end of this range. Buyers specifying burner capacity must match the fuel viscosity to the pump and heater design limits to avoid incomplete combustion.

Sulfur Content and Environmental Limits

Both Mazut 100 and Mazut 180 CST generally contain sulfur levels between 2.5 and 3.5 percent by mass classifying them as high sulfur fuel oil under ISO 8217 RMK categories. This sulfur content exceeds the 0.50 percent global cap enforced by IMO (2020 (in force)) for ships without scrubbers restricting marine use to vessels fitted with exhaust gas cleaning systems. Power plants and industrial boilers operating ashore remain the primary legal consumers provided local emission regulations permit high sulfur heavy fuel oil.

Flash Point and Pour Point Values

The flash point for both grades typically exceeds 60 degrees Celsius meeting the minimum SOLAS requirement for safe storage and handling aboard ships. Pour point differences are more pronounced with Mazut 100 often recording a maximum pour point of 24 degrees Celsius while Mazut 180 CST can reach 30 degrees Celsius. This higher pour point means the 180 grade requires heated storage tanks and trace heated piping in cooler climates to maintain pumpability. Terminal operators must verify tank heating coil capacity before accepting a cargo of the higher viscosity grade.

Parameter	Mazut 100	Mazut 180 CST	Test Method	Typical Limit
Kinematic Viscosity at 50°C	100 cSt	180 cSt	ISO 3104	Max
Density at 15°C	0.96, 0.99 kg/L	0.97, 0.99 kg/L	ISO 3675	Max
Sulfur Content			ISO 8754	Max
Flash Point	Min 60°C	Min 60°C	ISO 2719	Min 60°C
Pour Point	Max 24°C	Max 30°C	ISO 3016	Max

The table above summarizes the critical specification boundaries that separate Mazut 100 from Mazut 180 CST. Procurement teams should note that viscosity is the primary pricing differentiator while sulfur content remains identical across both grades. Flash point compliance is standard but pour point divergence dictates distinct storage infrastructure requirements. Always confirm the exact test certificate values against the sales contract annex before loading.

Viscosity-Temperature Relationship and Heating Requirements

ASTM D341 Walther Equation Application

The ASTM D341 Walther equation calculates the temperature required to reduce Mazut 180 CST to a target viscosity by plotting the double logarithm of kinematic viscosity against the inverse of absolute temperature. For a typical 180 cSt at 50°C fuel the constants A and B derived from two known viscosity temperature points yield a heating target of approximately 125°C to reach 20 cSt at the burner tip. Engineers use this calculation to size steam or electric heaters and to set the temperature controller setpoints on the fuel oil service module. Accurate viscosity temperature data from the certificate of quality is essential because small errors in the B constant produce large temperature deviations at the burner.

Target Atomization Viscosity for Burners

Pressure jet burners require a fuel viscosity between 15 and 20 centistokes at the nozzle to achieve a Sauter mean diameter below 100 microns for stable combustion. Rotary cup burners tolerate slightly higher viscosities up to 50 centistokes but most modern industrial boilers use pressure jet atomization. If the fuel arrives at the burner above 20 centistokes the spray cone angle narrows causing poor air fuel mixing and increased carbon monoxide and particulate emissions. The fuel oil heater must therefore deliver the calculated temperature consistently under maximum load conditions with a safety margin of at least 5 degrees Celsius.

Steam and Electric Heater Duty Calculations

Heater duty in kilowatts equals the mass flow rate in kilograms per hour multiplied by the specific heat capacity of the fuel oil (typically 2.1 kJ/kg·K) multiplied by the temperature rise divided by 3600. For a boiler burning 2000 kg/h of Mazut 180 CST heated from 50°C storage temperature to 125°C burner temperature the duty is approximately 87.5 kW. Steam heaters are sized on the same thermal load using the latent heat of condensation at the available steam pressure. Electric heaters offer simpler control but higher operating cost while steam heaters integrate with existing plant steam systems. Both heater types require low fuel oil flow interlocks to prevent coking on the heating elements.

Burner Compatibility and Atomization Targets

Rotary Cup Burner 40 cSt Target

Rotary cup burners achieve reliable atomization when Mazut viscosity reaches 40 centistokes at the burner tip. This viscosity target allows the spinning cup to form a stable fuel film that breaks into uniform droplets across the typical 300 to 1 turndown range. Operators heating Mazut 180 CST from 50 degrees Celsius storage temperature must raise fuel temperature to approximately 115 degrees Celsius to hit the 40 centistoke mark while Mazut 100 CST requires only about 95 degrees Celsius. Exceeding 45 centistokes causes the fuel film to thicken and produce larger droplets that increase carbon monoxide emissions and soot deposits on boiler tubes. Falling below 35 centistokes reduces the centrifugal force needed to overcome surface tension leading to poor spray pattern and flame instability.

Pressure Jet Burner Viscosity Limits

Pressure jet burners demand tighter viscosity control between 15 and 20 centistokes for effective atomization through the nozzle orifice. Mazut 100 CST reaches this window near 125 degrees Celsius while Mazut 180 CST requires approximately 140 degrees Celsius creating higher thermal stress on heater elements and piping. Nozzle selection must match the calculated flow rate at the target viscosity because a 10 percent viscosity deviation changes the spray angle by up to 15 degrees altering combustion chamber heat flux distribution. Modern pressure jet systems incorporate viscosity compensating valves that adjust fuel pressure to maintain constant mass flow but these cannot correct spray quality if viscosity drifts outside the 15 to 20 centistoke band. Dual fuel burners switching between gas and Mazut require separate nozzle lines or quick change nozzles to avoid cross contamination.

Preheat System Design Considerations

Preheat systems must deliver the target burner temperature under maximum load with a 5 degree Celsius safety margin to absorb ambient temperature swings and heater fouling. Steam heaters sized for Mazut 180 CST duty typically use 7 bar saturated steam providing 170 degrees Celsius heating medium temperature while electric heaters use sheathed elements limited to 200 degrees Celsius surface temperature to prevent coking. Temperature control loops use cascade architecture with the fuel outlet temperature controller setting the steam valve or electric power setpoint. Low flow interlocks trip the heater at 30 percent of design flow to protect elements from overheating during burner modulation. Insulation on preheat piping and the burner front header reduces heat loss and prevents cold spots where heavy fractions can plate out during startup and shutdown cycles.

ISO 8217 RMK Specifications and IMO 2020 Compliance

ISO 8217 RMK Grade Mapping

ISO 8217 RMK grade mapping aligns Russian GOST 10585 Mazut grades with international residual marine categories based on kinematic viscosity at 50 degrees Celsius. Mazut 100 CST corresponds to ISO 8217 RMK 100 with a maximum viscosity of 100 centistokes while Mazut 180 CST maps to RMK 180 with a maximum of 180 centistokes. Both grades share identical limits for density at 991 kilograms per cubic meter maximum, pour point at 30 degrees Celsius maximum, and carbon residue maximum on the distillation residue. The flash point minimum remains 60 degrees Celsius for all RMK grades. Vanadium limits differ with RMK 100 allowing 150 milligrams per kilogram and RMK 180 permitting 300 milligrams per kilogram reflecting typical crude slate variations. Sodium content is capped at 50 milligrams per kilogram for both grades to minimize hot corrosion in turbine blades.

Parameter	ISO 8217 RMK 100 Limit	ISO 8217 RMK 180 Limit	Mazut 100 CST Typical	Mazut 180 CST Typical	Test Method
Kinematic Viscosity at 50°C (cSt)	Max 100	Max 180	95-100	170-180	ISO 3104
Density at 15°C (kg/m³)	Max 991	Max 991	970-985	980-990	ISO 3675
Sulfur Content (mass %)	Max 3.50	Max 3.50	2.5-3.0	2.8-3.3	ISO 8754
Pour Point (°C)	Max 30	Max 30	18-24	22-28	ISO 3016
Carbon Residue (mass %)	Max 15	Max 15	10-13	12-14	ISO 10370
Vanadium (mg/kg)	Max 150	Max 300	80-120	150-250	IP 501

The table shows that Mazut 100 CST and 180 CST typically meet ISO 8217 RMK 100 and RMK 180 viscosity and density limits with comfortable margins on pour point and carbon residue. Sulfur content in both grades exceeds the 0.50 percent IMO 2020 limit requiring either blending with very low sulfur fuel oil or installation of exhaust gas cleaning systems for marine use. Vanadium levels in Mazut 180 CST approach the RMK 180 ceiling making fuel treatment additives necessary for gas turbine applications. Buyers should verify each cargo certificate of quality against these parameters before committing to term contracts.

IMO 2020 Sulfur Cap Strategies

Compliance with the IMO 2020 0.50 percent sulfur cap requires Mazut 100 CST and 180 CST to be either blended down or burned in scrubber equipped vessels per IMO (2020 in force). Blending calculations show that mixing one part Mazut 180 CST at 3.0 percent sulfur with three parts 0.10 percent sulfur VLSFO yields a compliant 0.83 percent blend still above the limit so a four to one ratio is the practical minimum. This dilutes the energy content and increases bunker cost depending on the VLSFO spread. Singapore's biofuel blend bunker sales grew to about 880,000 tons in 2024 according to MPA Singapore indicating growing acceptance of alternative compliance routes. Refiners also offer straight run VLSFO produced from low sulfur crude blends that meet RMK 100 viscosity without Mazut component.

Scrubber and Blending Options

Open loop scrubbers allow vessels to burn high sulfur Mazut 100 CST and 180 CST while meeting the 0.50 percent equivalent emission limit by washing exhaust with seawater per IMO (2020 in force). Closed loop systems use fresh water with caustic soda additive for operation in discharge restricted ports and inland waterways. Hybrid scrubbers switch between modes providing operational flexibility. Capital cost for a 20 MW scrubber system ranges from 2 to 4 million US dollars with payback periods of 12 to 24 months depending on the HSFO VLSFO price spread. Blending Mazut with low sulfur cutter stock at the terminal avoids onboard segregation but requires accurate in line blending systems and continuous sulfur monitoring. Terminals in Rotterdam, Fujairah and Houston offer certified blending services with quantity and quality guarantees backed by independent surveyors. Ship operators must declare the compliance method in the bunker delivery note and retain samples for port state control verification.

GSO 2195:2011 Gulf Standard Requirements

GCC Viscosity and Sulfur Limits

GSO 2195:2011 sets mandatory fuel oil specifications for all Gulf Cooperation Council member states including Saudi Arabia, UAE, Qatar, Kuwait, Bahrain and Oman. The standard defines two primary viscosity grades aligned with international norms: a 180 mm2/s at 50 °C grade and a 380 mm2/s at 50 °C grade. Maximum sulfur content is capped at 3.5 percent by mass for both grades which exceeds the IMO global limit but applies to domestic power generation and industrial boilers not engaged in international voyages. Density must not exceed 991 kg/m3 at 15 °C for the 180 grade and 1010 kg/m3 for the 380 grade. Flash point minimum is 60 °C for both grades ensuring safe handling in the region's high ambient temperatures.

Contaminant Thresholds Aluminum Silicon

GSO 2195:2011 imposes strict limits on catalytic fines measured as aluminum plus silicon with a maximum of 60 mg/kg for both viscosity grades. This threshold is tighter than the ISO 8217 RMK limit of 80 mg/kg reflecting the prevalence of gas turbine and high efficiency boiler installations across GCC power sectors. Sodium content is limited to 50 mg/kg maximum to control high temperature corrosion in turbines. Vanadium is capped at 300 mg/kg with a sodium to vanadium ratio requirement of less than 0.4 to minimize slag formation.

Certificate of Conformity Process

Every fuel oil shipment entering GCC ports requires a Certificate of Conformity issued by an approved notified body such as SASO in Saudi Arabia or ESMA in the UAE. The certificate references test reports from ISO 17025 accredited laboratories covering all GSO 2195:2011 parameters. Exporters must register the product in the Gulf Conformity Marking system before the first shipment. The process typically takes five to ten working days once complete documentation including the bill of lading, commercial invoice, packing list and full quality certificate are submitted. Non-compliant cargoes face rejection at port with re-export costs borne by the shipper. Importers should verify the notified body scope covers petroleum products before engaging.

HS Code 2710.19.06 Classification and Import Duties

HS Code 2710.19.06 Structure

HS Code 2710.19.06 covers petroleum oils and oils obtained from bituminous minerals other than crude preparations not elsewhere specified or included containing by weight 70 percent or more of petroleum oils or of oils obtained from bituminous minerals these oils being the basic constituents of the preparations waste oils excluded. The subheading specifically captures heavy fuel oil grades including Mazut 100 CST and 180 CST when viscosity exceeds the light oil threshold. The first six digits 2710.19 are harmonized globally while the final two digits 06 represent national subdivisions that vary by importing country. Accurate classification requires the certificate of quality showing kinematic viscosity at 50 °C and sulfur content to distinguish from gas oil or lighter fractions.

Major Market Duty Rates China India UAE

Import duty rates for HS 2710.19.06 differ significantly across major Mazut destinations. China applies a Most Favored Nation rate of 6 percent with zero duty under the Asia Pacific Trade Agreement for qualifying origins. India levies a basic customs duty of 5 percent plus 10 percent social welfare surcharge and applicable IGST bringing the effective rate to approximately 16.5 percent. The UAE applies a 5 percent GCC common external tariff with exemption for intra-GCC trade accompanied by a valid certificate of origin. Saudi Arabia maintains the same 5 percent GCC rate. South Korea applies 3 percent under its MFN schedule. Importers should verify current rates through national customs portals as temporary reductions or anti-dumping measures can alter effective costs.

Import Market	MFN Duty Rate	Preferential Rate Availability	Key Documentation
China	6%	APTA zero duty for qualifying origins	Certificate of Origin
India	5% + 10% SWS + IGST	SAFTA/ISFTA reduced rates	Certificate of Origin, IEC code
UAE	5% GCC CET	Zero for GCC origin	GCC Certificate of Origin
Saudi Arabia	5% GCC CET	Zero for GCC origin	GCC Certificate of Origin
South Korea	3%	AKFTA zero duty	Certificate of Origin Form AK

The table summarizes applied duty rates and preferential access conditions for five major Mazut import markets. The GCC countries apply a unified 5 percent common external tariff with duty-free treatment for intra-GCC movements when supported by a valid GCC Certificate of Origin. Preferential rates under free trade agreements require strict rule of origin compliance typically requiring the crude oil to originate in the FTA partner country. Importers should confirm current tariff schedules through official customs databases before contracting as rates can change with little notice.

Preferential Tariff Documentation

Claiming preferential duty rates requires a valid certificate of origin issued by an authorized chamber of commerce or government agency in the exporting country. For China under APTA the certificate of origin must be presented at customs clearance. For India under SAFTA or the India-Singapore FTA the respective certificate of origin forms are mandatory. GCC intra-trade relies on the unified GCC Certificate of Origin. South Korea under AKFTA accepts Form AK issued by authorized bodies. All certificates must match the commercial invoice description HS code and quantity exactly. Discrepancies trigger customs queries delaying clearance by seven to fourteen days. Exporters should prepare certificates concurrently with shipping documents to avoid demurrage at discharge ports.

Major Export Markets and Trade Flow Patterns

Primary Importing Nations Asia Middle East

China and India dominate Mazut 100 and 180 CST imports from Russia absorbing the largest share of Baltic and Black Sea export volumes. Chinese independent refineries in Shandong and Jiangsu process Mazut as a cost effective heavy feedstock for asphalt and fuel oil blending while Indian power plants and fertilizer units consume significant tonnage for baseload generation. Middle Eastern buyers including the UAE and Saudi Arabia import cargoes primarily for re export blending or domestic power generation during peak summer months. Turkey remains a consistent Mediterranean destination for smaller parcel sizes destined for industrial boilers and cement kilns.

Seasonal Power Generation Demand Cycles

Demand peaks sharply in the northern hemisphere winter from November through March when Russian domestic heating consumption reduces export availability and Asian buyers secure term contracts early. Summer demand shifts to the Middle East and South Asia where gas fired power plants switch to fuel oil during peak cooling loads or when LNG spot prices spike. Indian utilities typically tender for Mazut 180 CST in April ahead of the monsoon season when hydro output falls and thermal plants must compensate. Chinese teapot refineries increase run rates in the second half of the year to meet winter asphalt and heating oil requirements creating a predictable seasonal price premium over summer lows.

Baltic Black Sea and Pacific Load Ports

Baltic ports including Ust Luga Primorsk and Vysotsk handle the largest Suezmax and Aframax volumes destined for Europe Asia and the Mediterranean. Black Sea terminals at Novorossiysk and Tuapse serve Mediterranean and North African markets with shorter transit times. Pacific load ports Kozmino and De Kastri feed China Japan and South Korea directly via the Northern Sea Route in summer and via the Cape of Good Hope in winter. Ice class requirements and draft restrictions at Baltic ports limit winter loading to ice class 1A vessels while Black Sea operations continue year round. Exporters coordinate loading windows with icebreaker schedules published by Rosmorrechflot to avoid demurrage costs that can exceed 25000 dollars per day for delayed Suezmax vessels.

Blending Feedstock Value for Bunker Fuel Production

VLSFO Blending Component Economics

Mazut 100 CST serves as a primary heavy component in very low sulphur fuel oil production where its high density and residual carbon content allow blenders to meet the 0.50% m/m sulphur cap when combined with low sulphur cutter stocks such as marine gas oil or straight run diesel. Since 1 January 2020 the IMO limit on sulphur in ship fuel oil outside emission control areas was cut from 3.50% m/m to 0.50% m/m. Refiners target a final blend viscosity of 380 CST at 50 degrees Celsius requiring precise cutter stock ratios. The economic advantage lies in the price spread between high sulphur fuel oil and VLSFO. Blenders monitor the catalytic fines content of Mazut closely as levels above 60 mg per kg risk engine damage and limit the allowable blending ratio in premium bunker grades.

HSFO Blending for Scrubber Equipped Fleets

Mazut 180 CST remains the preferred feedstock for high sulphur fuel oil production targeting vessels equipped with exhaust gas cleaning systems. Its higher viscosity reduces cutter stock demand lowering blending costs compared to 100 CST grades. Bunker suppliers in Singapore, Rotterdam and Fujairah blend Mazut 180 CST with lighter cycle oils to achieve the ISO 8217 RMK 380 or 500 CST specifications required by scrubber fitted engines. The sustained demand from scrubber equipped fleets supports a structural price floor for Mazut 180 CST linked to the high sulphur fuel oil crack spread. Singapore's high-sulphur marine fuel sales totalled 20.15 million tons in 2024 according to MPA Singapore (via MarineLink) reflecting the continued relevance of this blending pathway.

Compatibility and Stability Testing

Every Mazut blend batch undergoes ASTM D4740 spot test and ASTM D7060 accelerated stability testing before release to ensure asphaltene precipitation does not occur during storage or co mingling with other fuels on board. A stability reserve number below 0.5 triggers rejection as the blend risks sludge formation in ship tanks and purifiers. Blenders also conduct compatibility testing against representative VLSFO and MGO grades using the ASTM D7157 method to simulate co mingling scenarios in vessel bunker tanks. Incompatible blends cause operational disputes and financial claims that can exceed the cargo value. Singapore's high-sulphur marine fuel sales rose 21% in 2024 from 2023 according to MPA Singapore (via MarineLink) increasing the volume of Mazut requiring rigorous pre delivery quality assurance protocols.

Power Generation and Industrial Boiler Applications

Utility Boiler Fuel Specifications

Utility boilers require Mazut 100 or 180 CST based on burner tip velocity and atomization pressure capabilities. Modern pulverized coal plants converted to heavy fuel oil typically specify Mazut 100 for its lower preheat temperature of 80 to 95 degrees Celsius which reduces steam tracing loads. Older tangential fired units with mechanical atomizers often mandate Mazut 180 CST because the higher viscosity at 50 degrees Celsius matches original design clearances. Sulphur limits in OECD nations frequently cap fuel oil at 1.0 percent by mass requiring flue gas desulphurisation or blending with low sulphur components. Ash content must remain below 0.1 percent to prevent fouling of superheater tubes and economisers. Vanadium and sodium ratios are monitored closely as high sodium accelerates high temperature corrosion on turbine blades.

Industrial Furnace and Kiln Requirements

Industrial furnaces and cement kilns select Mazut grades based on flame temperature stability and refractory life. Cement rotary kilns prefer Mazut 180 CST for its higher calorific density of approximately 40.5 MJ/kg which sustains the 1450 degree Celsius clinkering zone. Steel reheating furnaces often use Mazut 100 where rapid temperature cycling demands faster viscosity response during preheat cycles. Glass melting tanks require ash content below 0.05 percent and vanadium below 50 ppm to prevent crown corrosion and batch contamination. Ceramic tunnel kilns tolerate higher asphaltene content but demand consistent pour points below 24 degrees Celsius to ensure reliable pumping through ring mains. Fuel switching capability between gas and liquid fuel requires dual fuel burners with separate lances sized for the specific Mazut viscosity grade.

Fuel Handling and Storage Infrastructure

Fuel handling systems for Mazut require heated storage tanks maintained at 50 to 60 degrees Celsius for 180 CST and 40 to 50 degrees Celsius for 100 CST to keep viscosity below 500 cSt for centrifugal pumping. Trace heating on suction lines and discharge headers prevents cold slugs during winter startups. Settling tanks sized for 24 hour residence time allow water and sediment separation before centrifugal purifiers operating at 98 percent efficiency. Duplex filter arrangements with 25 micron absolute elements protect burner tips from catalyst fines and rust. Flow meters must be positive displacement or Coriolis type calibrated for viscosity ranges of 10 to 1000 cSt. Tank cleaning schedules follow API 653 inspection intervals with manual entry confined space protocols for sludge removal.

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Related reading: LPFO vs HFO: Specifications, Grades & Trading Differences.

Conclusion

What are the key takeaways for sourcing Mazut 100 and 180 CST fuel oil? Selecting the correct grade hinges on burner atomization capability and heating infrastructure. Mazut 100 CST suits installations with limited preheat capacity or smaller burner tips while Mazut 180 CST offers higher energy density and lower unit cost for facilities equipped to maintain 130 to 150 degrees Celsius at the burner. Both grades must meet ISO 8217 RMK category limits for sulfur, aluminum plus silicon, and used lubricating oil indicators to ensure combustion reliability and compliance with IMO 2020 regulations for non-marine applications. Gulf buyers must additionally verify GSO 2195:2011 pour point and flash point requirements before confirming orders. Trade flows remain concentrated on Black Sea and Baltic export terminals with pricing anchored to Argus FOB assessments and SPIMEX domestic netbacks. Logistics demand heated tankers with Class II or III chemical notation and robust SBLC or documentary credit structures aligned to FOB or CIF Incoterms 2020. Buyers should verify counterparty bank ratings, confirm quality certificates against loading port surveyor reports, and track viscosity-temperature curves to avoid operational disruptions during discharge and storage. For verified supplier listings and trade data on active importers, Global Trade Plaza and EximDataX offer practical starting points for due diligence.

Frequently Asked Questions

What is the typical sulfur content of Russian Mazut 100?

Russian Mazut 100 typically contains sulfur between 2.5 and 3.5 percent by mass. This range classifies it as high sulfur fuel oil under ISO 8217 RMK categories and exceeds the IMO 2020 0.50 percent global cap for marine use without scrubbers.

How much preheat temperature does Mazut 180 CST need for pumping?

Mazut 180 CST generally requires heating to approximately 115 degrees Celsius to reach 40 centistokes for rotary cup burners or 140 degrees Celsius to reach 15 to 20 centistokes for pressure jet atomization. Storage tanks must stay above the pour point near 30 degrees Celsius to maintain pumpability.

Can Mazut 180 CST be used directly in marine engines without blending?

No, Mazut 180 CST cannot be used directly in marine engines without blending or exhaust gas cleaning systems because its sulfur content of 2.5 to 3.5 percent exceeds the IMO 2020 0.50 percent global sulfur cap. Only vessels fitted with scrubbers may legally burn it as bunkers.

What is the flash point minimum for Mazut 100 under GOST 10585-2013?

The flash point minimum for Mazut 100 under GOST 10585-2013 is 60 degrees Celsius. This aligns with the ISO 8217 RMK 100 minimum and the SOLAS requirement for safe storage and handling aboard ships.

Which HS code applies to Mazut fuel oil exports from Russia?

HS Code 2710.19.06 applies to both Mazut 100 and Mazut 180 CST exports from Russia. This classification covers heavy fuel oils derived from petroleum or bituminous minerals not elsewhere specified.

What are the main import ports for Mazut in China?

Major Chinese import ports for Mazut include Zhoushan, Qingdao, Rizhao, and Huanghua. These terminals handle bulk fuel oil deliveries for independent refineries and power plants along the eastern seaboard.

How does Mazut 100 compare to RMK 380 marine fuel?

Mazut 100 corresponds to ISO 8217 RMK 100 with a maximum viscosity of 100 centistokes at 50 degrees Celsius while RMK 380 allows up to 380 centistokes. Mazut 100 requires significantly less preheating and suits smaller industrial burners rather than large marine engines.

What is the pour point range for Mazut 180 CST winter grades?

Mazut 180 CST winter grades typically target a pour point below 15 degrees Celsius often achieved through depressant additives. Standard summer grades can reach a maximum pour point of 30 degrees Celsius requiring heated storage in cool weather.

Are there sanctions restrictions on buying Russian Mazut fuel oil?

Yes, EU, UK, and US sanctions restrict purchases of Russian petroleum products including Mazut with limited wind-down periods and price cap mechanisms. Buyers must verify current licensing requirements and payment channel restrictions before contracting cargoes.

What testing lab certificates do buyers require for Mazut cargoes?

Buyers typically require a Certificate of Quality from an independent inspector such as SGS, Intertek, or Saybolt covering ISO 3104 viscosity, ISO 8754 sulfur, ISO 2719 flash point, and ISO 3016 pour point. GCC destinations also mandate a Certificate of Conformity from SASO or ESMA.

How is Mazut 100 priced relative to Brent crude benchmarks?

Mazut 100 is typically priced at a discount to Brent crude on a per-barrel basis reflecting its high sulfur content and residual nature. The exact differential varies by region and freight economics with Platts FOB Med or Black Sea assessments serving as common markers.

What tanker cleaning requirements apply after carrying Mazut 180 CST?

Tankers carrying Mazut 180 CST require thorough hot washing with detergent solutions followed by freshwater rinsing and gas-freeing to remove heavy residue and hydrogen sulfide. The process must meet the next charterer's cleanliness standard often verified by a Wall Wash Test before loading clean products.

Sources

• MPA Singapore (via MarineLink) (2024): Singapore high-sulphur fuel oil bunker sales
• MPA Singapore (via gCaptain) (2024): Singapore biofuel blend bunker sales
• IMO (2020 (in force)): IMO global marine fuel sulphur limit