TBN 400 Lubricant additive
Time：
2025-10-11
TBN 400 for the Lubricant Industry: A Practical, Field-Ready Guide
Total Base Number (TBN) describes the alkaline reserve of an oil. It is one of the most important numbers for engine oils that face acidic by-products from fuel sulfur and blow-by, and for certain industrial oils that must manage acidic contamination. This guide explains what a high-reserve material like tbn 400 is in practice, where it fits, how to use a tbn booster safely, how to run the common tests, and how to troubleshoot real plant and vessel issues without guesswork. The goal is simple, useful guidance you can apply on a blending floor, in a lab, or beside a crankcase or sump.
1) What TBN Means in Day-to-Day Work
Total Base Number (TBN) is a measure of how much basic (alkaline) material an oil contains to neutralize acidic compounds. It is reported in milligrams of potassium hydroxide per gram of oil (mg KOH/g). In a fresh engine oil, TBN reflects the strength of the detergent and overbased components that are there to catch and neutralize the acids formed during combustion.
Two industry methods are commonly used to measure TBN: ASTM D2896 and ASTM D4739. D2896 uses a strong acid titrant and usually gives a higher number; D4739 is milder and often closer to what used oil analysis shows in service. When you compare data sheets or used oil results, match the method first before you draw conclusions.
2) What People Mean by “tbn 400”
In blending rooms and sourcing teams, the term tbn 400 usually points to a very high reserve, overbased detergent concentrate with a nominal TBN near 400 mg KOH/g. These are often calcium-based or magnesium-based sulfonate, phenate, or salicylate systems that contain a dispersed alkaline core (such as carbonate) stabilized by an organic surfactant. They are not finished oils. Instead, they are strong “reserve packages” used in small treat rates to boost a finished oil’s TBN or to build a high-TBN cylinder oil for large two-stroke engines.
Because tbn 400 materials are highly basic and often viscous, they change more than one property when you add them to a formula. Besides raising TBN, they may affect ash, viscosity, seal behavior, deposit tendency, and water handling. That means the “right dose” is decided by the full specification you must meet, not by TBN alone.
3) Where High-Reserve Detergents Fit (and Where They Do Not)
There is no one-size-fits-all answer for TBN. Think in terms of application and risk.
| Application | Why Alkaline Reserve Matters | Typical Practice | What to Watch |
|---|---|---|---|
| Large two-stroke marine cylinder lubrication | Neutralize strong acids from high sulfur fuel in the liner area | High-TBN cylinder oils built with strong overbased packages (including tbn 400) | Deposit control on ports and rings; feed rate control; matching fuel sulfur |
| Four-stroke marine and stationary diesels | Handle acids from fuel and blow-by; protect bearings and liners | Finished oils with TBN selected to match fuel sulfur and duty | Used oil TBN trend vs. TAN, oxidation, and wear metals |
| On-highway and light-duty diesels | Modern fuels have lower sulfur; aftertreatment is sensitive to ash | Moderate TBN oils per current specifications | Ash, SAPS limits, compatibility with DPF/SCR hardware |
| Industrial systems exposed to acidic ingress | Acidic contamination from process leaks or reactions | Targeted use; sometimes a controlled tbn booster during reclamation | Overtreatment risk; filter plugging; additive balance |
4) What Is Inside a High-Reserve Detergent
Most high-reserve detergents contain an organic “head” that keeps the package soluble and a dispersed alkaline “core” that supplies the reserve. The common organic heads are sulfonates, phenates, and salicylates. The core is often a carbonate-type structure. Calcium is the most frequent metal, with magnesium used in some packages.
Why this matters to you: the head type changes how the package behaves in soot control, deposit handling, and compatibility. If you are swapping one high-reserve source for another, check not only TBN but also metal type, head type, and any supplier handling notes, because they influence blending behavior and finished oil performance.
5) How TBN Is Measured and Reported
ASTM D2896 uses perchloric acid in acetic acid to titrate the base content. Fresh oils measured by D2896 can look “higher” than when measured by other methods. ASTM D4739 uses hydrochloric acid in a propan-2-ol medium and typically gives a lower, more service-representative number, especially for used oils.
Practical lab pointers
- Match the method (D2896 or D4739) when trending data. If you switch methods mid-trend, note the change.
- Report the method with the number for clarity on data sheets and blend records.
- When testing used oil, also watch TAN (Total Acid Number). A falling TBN and rising TAN together signal acid stress.
6) FAQs
Is tbn 400 a finished oil?
No. It usually refers to a high-reserve detergent concentrate used at low treat rates to raise the TBN of a finished oil or to build a high-TBN product.
Can I solve every acid problem by adding more reserve?
No. Reserve helps, but root causes like fuel sulfur, poor combustion, or acidic process ingress remain. Address the cause first, then size the reserve.
Which TBN method should I use for trending?
Use one method consistently. Many labs prefer D4739 for used oil because it tracks service depletion more closely for some oils. If you switch methods, note it clearly.
What is a safe way to try a tbn booster in service?
Run a pilot. Calculate a small treat rate by weighted average, blend a lab sample, verify full properties, then apply in steps with filter and deposit monitoring.
Does a higher TBN always mean better protection?
No. The “best” TBN is the one that matches the acid load and OEM targets without causing ash and deposit issues.
Why did my demulsibility get worse after a TBN correction?
Previous page
Next page
Previous page
Next page
PRODUCTS CENTER
MORE BLOG
2025-10-11
2025-09-29
2025-09-22
2025-09-17
2025-09-15
CheMost
CheMost Additives CO.,LTD
ADDRESS: CheMost Additives CO.,LTD, Jinzhou city, Liaoning provice, China
Copyright© 2025 CheMost Additives CO.,LTD
Website：300.cn jinzhou.300.cn | SEO | Privacy Policy