When sourcing Cashew Shell Pellets (CNSP) for industrial boiler combustion, international buyers and plant engineers must review a crucial document before placing an order: the Certificate of Analysis (COA) or lab test report.
Issued by independent laboratory testing bodies like SGS, Bureau Veritas, or Eurofins, a COA verifies the physical characteristics, chemical composition, and thermal performance of the biomass fuel.
If you are a first-time buyer exploring cashew shell biomass, this guide breaks down every key specification listed on a standard COA, explaining what each parameter means, why it matters for your boiler, and what ideal benchmark numbers to look for.
Table of Contents
Standard Specifications (COA) Benchmark for Export-Grade CNSP
| Specification Parameter | Standard Industry Range | Premium Grade Benchmark | Impact on Boiler Performance |
| Gross Calorific Value (GCV) | 4,500 – 4,800 kcal/kg | $> 4,800\text{ kcal/kg}$ | Determines heat yield and steam generation speed |
| Net Calorific Value (NCV) | 4,200 – 4,500 kcal/kg | $> 4,500\text{ kcal/kg}$ | Actual usable thermal energy in real furnace operations |
| Moisture Content | $\le 10\%$ | $\le 8\%$ | Affects ignition speed, heat loss, and shelf life |
| Ash Content | $3.0\% – 5.0\%$ | $\le 3.5\%$ | Dictates ash removal frequency and grate slagging risk |
| Volatile Matter | $65\% – 72\%$ | $68\% – 72\%$ | Influences flame stability and combustion ease |
| Fixed Carbon | $16\% – 20\%$ | $18\% – 20\%$ | Determines heat retention and long ember combustion |
| Total Sulfur (S) | $\le 0.08\%$ | $\le 0.05\%$ | Controls acidic corrosion and $\text{SO}_2$ emissions |
| Pellet Diameter & Length | $8\text{ mm} – 10\text{ mm} \times 20-40\text{ mm}$ | Uniform $8\text{ mm}$ / $10\text{ mm}$ | Ensures smooth automated feeding without jam risks |
Key COA Parameters Explained for First-Time Buyers
1. Gross Calorific Value (GCV) vs. Net Calorific Value (NCV)
Calorific value measures the total thermal energy released when $1\text{ kg}$ of fuel burns completely.
- Gross Calorific Value (GCV / High Heating Value): The potential energy content under laboratory conditions, including the latent heat of water vaporized during combustion. Premium cashew shell pellets reach $4,600 – 4,900\text{ kcal/kg}$.
- Net Calorific Value (NCV / Low Heating Value): The actual usable heat delivered inside your boiler furnace after subtracting the energy required to evaporate moisture.
- Buyer Tip: Always evaluate pricing against NCV, as this directly reflects real-world steam production per dollar spent.
2. Moisture Content ($\le 8\% – 10\%$)
Moisture represents the percentage of water trapped inside the compressed pellet matrix.
- Why low moisture matters: Water absorbs energy during evaporation, lowering effective furnace temperatures. Pellets with high moisture ($> 12\%$) ignite poorly, produce dark smoke, and degrade faster in storage hoppers.
- The Benchmark: High-grade CNSP undergoes heavy thermal drying during extrusion, keeping final moisture content tightly controlled at $\le 8\%$.
3. Ash Content ($3.0\% – 5.0\%$)
Ash is the non-combustible inorganic residue left behind after the organic biomass burns completely.
- Impact on Machinery: High ash content leads to clinkering (slag formation on grate bars) and requires more frequent tube cleaning.
- Understanding CNSP Ash: While wood pellets average $1–2\%$ ash, cashew shell pellets naturally contain $3–4\%$ ash due to mineral absorption in the shell wall. Modern chain-grate and reciprocating-grate boilers process $3–4\%$ ash effortlessly with automated de-ashing systems.
4. Volatile Matter vs. Fixed Carbon
These two parameters dictate how fuel behaves across different burning zones inside the boiler furnace:
- Volatile Matter ($65\% – 72\%$): The gases released when biomass is exposed to heat. High volatile content ensures quick ignition and low ignition energy requirements.
- Fixed Carbon ($16\% – 20\%$): The solid carbon framework that remains after volatile gases burn off. Higher fixed carbon yields sustained ember heat, keeping thermal output steady between feeding cycles.
5. Total Sulfur (S) and Chlorine (Cl) Limits
Industrial emission regulations impose strict limits on sulfur and chlorine levels in boiler fuels.
- Sulfur ($\le 0.05\%$): Low sulfur content prevents sulfur dioxide ($\text{SO}_2$) emissions and protects boiler heat exchangers from acidic gas corrosion.
- Chlorine ($\le 0.05\%$): Low chlorine levels prevent severe high-temperature corrosion on boiler tubes and reduce slag formation.
6. Physical Dimensions & Bulk Density
Mechanical specifications ensure smooth physical handling throughout your automated fuel feeding line:
- Diameter: Standardized at $8\text{ mm}$ or $10\text{ mm}$ to match automatic screw feeders and conveyor belts.
- Bulk Density ($1,100 – 1,300\text{ kg/m}^3$): High density prevents pellets from crumbling into dust (fines) during sea transit and pneumatic loading, ensuring clean, dust-free fuel handling at your plant site.
How to Verify COA Authenticity Before Placing a Bulk Order
- Request a Recent Lab Report: Ensure the COA was issued within the last 3–6 months by an accredited international testing laboratory (SGS, Bureau Veritas, Eurofins, or Quatest).
- Order Pre-Shipment Inspection (PSI): For full container load (FCL) shipments, instruct an independent inspection firm to sample directly from factory bags or container loading ports.
- Test Factory Samples: Request a $2–5\text{ kg}$ physical sample from your supplier to run a trial burn in your laboratory or pilot furnace.
Source Verified High-Spec Cashew Shell Pellets with The One General Trader
At The One General Trader, transparency and strict quality control drive every shipment. We provide full, verifiable lab testing certificates (COA) with every export batch, ensuring that our Vietnamese Cashew Nut Shell Pellets consistently deliver:
- Calorific Heat Output: $> 4,600\text{ kcal/kg}$
- Moisture Content: $\le 8\%$
- Ash Content: $< 4.0\%$
- Zero Foreign Impurities or Chemical Binders
Need a verified COA lab report or sample package for your technical team?
Contact The One General Trader today to receive technical specification sheets, lab testing documentation, and competitive FOB/CIF price quotes!