Knowledge Hub on Industrial Pelleting

Standard equipment of GR pellet mills — what do you get in the package?

The standard equipment of GR pellet mills includes all the components needed to start up the production line immediately. Every pellet mill in the GR series — from the compact GR 420 to the industrial giant GR 880 — leaves the Nawrocki factory as a complete, ready-to-run unit.

What is included as standard?

Every GR pellet mill is fitted as standard with: an IE3-class 6-pole electric motor (980 rpm), a bevel-helical gearbox integrated with the granulating chamber, an automatic CALS lubrication system with a progressive valve, an overload clutch protecting the die and rollers, a magnetic separator removing ferromagnetic particles from the raw material, a fan cooling the drive motor, temperature and vibration sensors on the gearbox bearings, and a full control panel with the AIAC system.

Die and rollers — the heart of the system

The standard price includes a ring die made of X46Cr13 steel, vacuum-hardened, machined on CNC centres with a precision of up to 0.01 mm. Complete rollers with induction hardening up to 62 HRc provide a service life of 2500–4000 operating hours. Both of these parts determine the quality and repeatability of pellet production.

Safety and communication

The ASAFE (Automatic Safety System) is also standard, with vibration, temperature and steam-pressure sensors that protect the machine from operating under fault conditions. Ethernet and PROFIBUS communication interfaces ensure integration with the higher-level production management system.

FAQ — frequently asked questions

Optional equipment of GR pellet mills — tailoring the machine to the needs of the line

The modularity of GR pellet mills allows the machine to be precisely matched to the specifics of the pellet being produced — poultry feed, biomass pellets, fish feed, fertilizer granulate or wood pellets. Nawrocki offers a range of proven optional modules that integrate seamlessly with every model in the GR series.

Key technological options

• ARGAS (patent P-405199) — automatic remote adjustment of the gap between the rollers and the die without stopping the machine; increases line throughput by a minimum of 2–4% per year.
• AOBP (Automatic Overload By-Pass) — a pneumatic bypass valve protecting the pellet mill from load spikes.
• PQPC — an automatic sampler for ongoing pellet quality control without operator intervention.
• FFFU (Force Feed Feeder Unit) — a force-feed feeder for raw materials with low bulk density, e.g. straw, hay or sawdust.
• QDES.60 — a quick die-change system in under 60 minutes, reducing downtime by more than 70%.

Sanitary and anti-corrosion options

For the fish and food industries, a stainless steel package is available (granulating chamber, feed screw, conditioner), and the ATEX option enables operation in dust explosion hazard zones (Directive 2014/34/EU). Each option can be ordered from the factory or retrofitted by Nawrocki service.

FAQ — frequently asked questions

How to reduce energy consumption in biomass pelleting?

In biomass pelleting, the cost of electricity is one of the largest items in a line's operating budget. That is why a real cost advantage is built not by increasing motor power, but by lowering the unit energy consumption — the number of kilowatt-hours needed to produce one tonne of finished pellet.

What does kWh/t really depend on?

• Raw material moisture — deviations from the optimal range increase pelleting resistance and reduce pellet durability.
• Die selection — the right ratio of thickness to hole diameter (compression) determines the extrusion resistance.
• Even feeding — surging feed causes operation away from the nominal point and energy losses.
• Process automation — the AIAC system keeps the machine at optimal load, limiting overheating and downtime.

Measurement instead of estimation

Without an energy meter and a flow scale, cost cannot be managed. Measuring kWh/t makes it possible to compare recipes, dies and settings objectively, and to catch wearing components before they show up on the bill.

The role of the motor and gearbox

An IE3-class motor and a precise bevel-helical gearbox reduce mechanical losses, but their potential only shows under stable, continuous load. GR series pellet mills are designed precisely for continuous operation at the nominal point.

FAQ — frequently asked questions

2 or 3 rollers? Differences in pellet mill design

The number of rollers is one of the key design parameters of a ring-die pellet mill. It determines how often each part of the die is pressed in a single revolution, and therefore the evenness of operation and the maximum throughput.

Two-roller layout

It works well in small and medium machines and with raw materials that are easy to pelletise. It is simpler to service and cheaper to run, and at moderate throughputs it provides fully stable operation.

Three-roller layout

At larger die diameters, the third roller shortens the interval between successive pressing cycles. The material is compacted more often and more evenly, which translates into higher and more stable throughput and smaller fluctuations in motor load.

What does this mean for the investor?

• Predictability — smaller throughput fluctuations in continuous operation.
• Die utilisation — more even wear of the working surface.
• Scaling — the three-roller layout copes better with the high throughputs of large models, e.g. the GR 880.

FAQ — frequently asked questions

Wood pellet market in the EU — trends and forecasts

The wood pellet market in the European Union is growing along with the decarbonisation policy for heating and distributed energy. At the same time, it is becoming increasingly demanding — buyers expect certified quality and stable supplies.

Key trends

• Certified quality — standards such as the ENplus A1 class are becoming a condition for entering the premium market.
• Energy cost pressure — volatile electricity prices reward lines with low kWh/t.
• Shorter supply chains — local raw material and production close to the buyer are gaining importance.
• Documenting efficiency — audits and certificates support investment financing.

How to maintain the margin?

An advantage is built through quality repeatability and low unit cost. A stable process — from raw material preparation to pelleting — reduces complaints and allows sales to be planned in the premium segment, which is less sensitive to price fluctuations.

The role of technology

GR series machines are designed for continuous operation and repeatable pellet quality, which translates directly into the producer's position in the demanding EU market environment.

FAQ — frequently asked questions

Step by step: how to apply for white certificates

White certificates (energy efficiency certificates) are issued by the Energy Regulatory Office. To obtain them, proper preparation of the application is crucial — and most of the work is done before purchasing a new line.

Order of actions

• 1. Baseline — gathering data on current energy consumption and process parameters.
• 2. Energy efficiency audit — comparing the current state with the planned investment and calculating annual savings.
• 3. Application to URE — submitting the documentation before carrying out the project.
• 4. Implementation and confirmation — implementing the investment and verifying the savings achieved.

Why does the order matter?

The application should be submitted before the project is carried out. Submitting it after the fact makes obtaining the certificate significantly harder or impossible, so it is worth combining certificate planning with the choice of technology supplier.

The role of the pellet mill's technical data

The machine's parameters — power, efficiency, unit energy consumption — become part of the justification of savings. The better documented they are, the stronger the application.

FAQ — frequently asked questions

Raw material moisture and pellet quality — what you need to know

Raw material moisture is one of the most important — and most often underestimated — parameters of the pelleting process. It affects pellet durability, energy consumption and the stability of machine operation all at once.

Too dry and too wet

• Raw material too dry — extrusion resistance through the die rises, the pellet can be brittle, and energy and parts consumption increases.
• Raw material too wet — the process loses stability, there is a risk of clogging and a need for more intensive drying.

Optimal moisture window

For most wood biomass, the optimal range lies within a narrow window that is worth establishing experimentally for the given raw material and recipe. Keeping to this window determines the repeatability of quality.

Measurement and control

Measuring moisture at the inlet, combined with a steam conditioner and process automation, makes it possible to react quickly to changes in raw material batches. This is the cheapest way to reduce energy losses and quality complaints.

FAQ — frequently asked questions

Simultaneity factor in industrial installations

The simultaneity factor describes what portion of the installed power actually operates at the same time. In industrial installations, all devices rarely reach their maximum at once — and that is precisely why installed power overstates the estimated energy consumption.

Why is this important?

• Real energy cost — what counts is the actual draw, not the sum of rated powers.
• Connection sizing — overestimation leads to overly expensive supply infrastructure.
• Credible ROI — a calculation based on the load profile is closer to reality.

What to include in the calculation

A reliable calculation must include the load of the main motor, running time under full feed, technological stoppages (die replacement, cleaning) and auxiliary equipment — feeders, the conditioner, the cooler and the dedusting system. Only their combined profile gives the energy cost per tonne of finished pellet.

How to translate this into an investment decision?

Instead of comparing machines by rated power, it is worth comparing them by energy cost per tonne under a real operating profile. Such a picture is provided by the ROI calculator, which accounts for the line's load and running time.

FAQ — frequently asked questions