Heavy-duty diesel engines in long-haul trucks, construction machinery, and mining equipment operate under higher acid loads than gasoline engines - higher fuel sulphur content, greater blow-by from higher cylinder pressures, and longer target drain intervals (50,000–100,000+ km in Euro VI OEM-approved programmes). High TBN Calcium Sulfonate provides the TBN reserve and detergency required by API CK-4/FA-4 and ACEA E6/E9 at economically optimised treat rates, delivering more TBN per kilogram of additive than any lower TBN grade at equivalent sulphated ash contribution.

Medium-speed marine trunk piston engines operating on distillate (MGO, MDO) or low-sulphur heavy fuel require finished oil BN 20–40 mgKOH/g for adequate acid neutralisation and corrosion protection in the marine salt-air environment. High TBN Ca sulfonate at TBN 300–400 provides the concentrated TBN delivery to reach these finished oil targets at commercially viable treat rates. Stationary large diesel generators at power stations and industrial facilities have similar requirements.

Gas engines and dual-fuel engines operating on CNG, LNG, or biogas generate nitric acid (from NOₓ blow-by) and formic/organic acids (from partial combustion of gas hydrocarbons) that require a moderate TBN reserve in the finished oil. High TBN Ca sulfonate provides the TBN delivery needed for gas engine oil formulations targeting BN 8–15 mgKOH/g at treat rates compatible with the lower ash tolerance of gas engine catalytic aftertreatment (where applicable). The aromatic sulfonate backbone also provides thermal stability under the high-temperature combustion environment of lean-burn gas engines.

Off-road diesel engines in mining, agriculture, forestry, and construction in many markets continue to operate on diesel fuel with sulphur content 500–5000 ppm (or higher in some developing-market off-road segments). Higher fuel sulphur generates proportionally more H₂SO₄ in the combustion chamber and blow-by gases, demanding a higher TBN reserve in the engine oil. High TBN Calcium Sulfonate at TBN 300–400 provides the concentrated neutralisation capacity required to maintain finished oil TBN above the critical minimum throughout the extended drain intervals typical of off-road equipment operating in remote locations.

Q: What is the difference between High TBN (300–400) and Overbased (>400) Calcium Sulfonate?

Both are highly overbased, but High TBN (300–400 mgKOH/g) is the standard grade for HDDEO and marine TPEO (distillate fuel) - it provides the concentrated TBN delivery needed for finished oils targeting BN 10–40 mgKOH/g at treat rates of 1.5–4 wt%. Overbased (>400 mgKOH/g) is a high-concentration TBN carrier used primarily as a blending component in marine cylinder oil concentrates (BN 40–100+ in the finished oil) or as a production intermediate. Overbased grades have even higher viscosity (often semi-solid at ambient) and density, requiring more intensive heating for handling. For most HDDEO formulations, High TBN at 300–400 provides the optimal balance of TBN delivery, processability, and cost.

Q: Can High TBN Calcium Sulfonate be used for calcium sulfonate grease production?

Yes - High TBN Ca sulfonate can be used as the base material for calcium sulfonate grease, and it provides a higher thickener yield per kilogram (more colloidal CaCO₃ per unit weight) than Medium TBN. However, the very high viscosity of High TBN grades (50–200 cSt @100°C) increases the complexity of the grease production process and may require higher process temperatures for homogenisation. Medium TBN (150–300 mgKOH/g) is more commonly used for calcium sulfonate grease production as it offers a better balance of thickener yield, processability, and base oil contribution to the finished grease viscosity. Contact our technical team to confirm which sub-grade is optimal for your grease production process and target NLGI grade.

Q: Why is High TBN Calcium Sulfonate so viscous, and how should I handle it in winter?

High viscosity (50–200 cSt @100°C; much higher at ambient) results from the extremely high colloidal CaCO₃ micelle loading - CaCO₃ particles at 10–16% calcium by weight increase the product's intrinsic viscosity far above any base oil alone. In cold weather (<15°C), the product may become difficult or impossible to pump without pre-heating. Recommended practice: heat drums or IBC to 60–80°C using a drum heater or hot room for 12–24 hours before use. For bulk ISO tank deliveries, request a tank with heating coils and maintain temperature throughout discharge. Never apply open flame directly to drums. Steam heating should not exceed 120°C.

Q: What finished oil TBN can I achieve with High TBN Calcium Sulfonate, and at what treat rate?

As a rough guide for the TBN 350 sub-grade (Ca ~13 wt%, density ~1.09 g/cm³): 1 wt% treat rate in finished oil ≈ 3.5 mgKOH/g TBN contribution. For a target finished oil TBN of 14 mgKOH/g (typical API CK-4 heavy-duty diesel), approximately 4 wt% of TBN 350 Ca sulfonate is required from the detergent component alone - in practice this is often split between High TBN Ca sulfonate (primary TBN delivery) and Medium TBN Ca sulfonate or overbased Mg sulfonate (supplementary detergency and ash efficiency optimisation). Exact treat rates depend on target finished oil TBN, drain interval, sulphated ash limit, and co-additive package. Sinolook's technical team provides formulation support including treat rate calculations on request.

Related: Low TBN Calcium Sulfonate · Medium TBN Calcium Sulfonate · Overbased Calcium Sulfonate · Overbased Magnesium Sulfonate · Primary ZDDP · PIB Bis-Succinimide Dispersant