Pellet Line: From Sand to Floor and Hall: How FEED is Building a Wet Sawdust Pellet Plant
Introduction: A pellet factory starts in the sand, not in an assembly hall
Before the first ton of pellets leaves the pellet mill (or, even better, 4 tons per hour), the project goes through a rather uninspiring phase: foundations, process ducts, cable conduits, and a floor with planned recesses for machinery. It's during this time that decisions are made that can't be cheaply changed after the concrete is poured.
In photos from the construction site, we show what this stage looks like in practice—from the sand-filled foundation outline, through the assembly of the steel structure and sandwich panel cladding, to the finished floor with utilities installed. Every culvert, every channel, and every "island" of sand left in the floor stem from a single document: the FEED project, prepared jointly by the investor and Nawrocki.
Nawrocki has been designing and manufacturing granulators and complete turnkey granulation lines since 1996. We know from experience that the timing and cost of a line's launch are largely determined by what happens on site long before the first machine arrives.
What is FEED and why does it determine the foundations of a pellet factory and the method of processing sawdust and producing pellets?
FEED (Front-End Engineering Design) is the basic project design that translates granulation technology into specific construction requirements. It is developed after the concept and before the detailed design. It answers questions such as where each machine will be located, how much it weighs, how it operates, and what it requires from the building.
This is especially important for granulation lines. The dryer, hammer mill, granulator, conditioner, cooler, screen, conveyors, and bucket elevators transfer static and dynamic loads to the ground, requiring power, controls, and utilities, and often recesses in the floor. If this information isn't provided to the construction designer in time, the contractor will pour the floor "smoothly"—and then have to chisel it out.
What FEED determines | As you can see on the construction site |
Machine layout (line layout) | The axes of the foundations and islands for machines marked out with a laser level |
Machine loads and vibrations | Machine foundations made separately, separated from the floor |
Elements below floor level | Technological channels and recesses left in the slab |
Power and control cable routes | Casing pipes led out precisely at the locations of future receivers |
Utility points (water, air, sewage) | Installation approaches to walls and floors |
Dimensions and communication | Hall height, gates and transport routes for machine deliveries |
Pellet line: What you can see in the photos: step-by-step construction of the production hall for the pellet line
The photos show four stages: foundations with underground utilities, hall structure and enclosure, slab with machinery reserves, and finished floor with utilities installed. Everything seen here originates from FEED drawings.
Stage 1: foundations, backfill and underground utilities
Photo 1. The new building's outline is defined by concrete foundation walls with protruding reinforcing bars that will connect them to subsequent structural elements. The interior is filled with compacted sand backfill—the substrate for the future floor slab. Inside, an elongated concrete service pit with starter bars is visible. Blue corrugated casing pipes protrude from the sand at precisely defined points: these are the future cable outlets for the machines. In the background are the investor's existing plant halls.
Photo 2. A wider shot of the same stage. Visible are orange PVC sewer pipes, a concrete manhole, and bundles of conduit and cables threaded through the foundation wall. Track and wheel tracks indicate extensive earthworks. At this stage, each culvert relocation costs little—once concreted, it costs many times more.
Stage 2: steel structure and sandwich panel cladding
Photo 3. The hall now has a galvanized steel structure and sandwich panel walls on a concrete base. The openings for the window strips that illuminate the interior and the gate opening are visible. A telehandler and a basket lift are operating on the building, and the surrounding area has been paved with aggregate.
Photo 4. Interior of the drying hall casing under construction. The roof is not yet covered—purlins and bracing are visible. The installer is working from the basket of an articulated boom lift. This is a stage where safety at height and coordination of panel deliveries are crucial.
Stage 3: plate with reserves for machines
Photo 5. The slab has already been poured inside, but a rectangular "island" of sand with casing pipes and a channel with starting reinforcement have been intentionally left inside. These are the locations for the machine foundations and line elements, which will be concreted in a separate stage, after confirming the dimensions from the machine documentation. A galvanized frame structure for the control room and restroom stands against the wall, and next to it, a laser level on a tripod—a sign that the elevations are constantly monitored.
Photo 6. Close-up of the reserve. The outlets of the protective pipes (corrugated arota) were sealed with tape to prevent sand or concrete from getting into them. This small measure of protection later saves hours of pulling cables through clogged pipes.
Photo 7. A patch with a laser receiver lies on the floor. The contractor checks the level of the channel edges and reserves before commencing the next concreting. In the background, the casing is being installed.
Photo 8. View along the service pit. Rainwater is standing at the bottom—the roof hasn't been sealed yet. Before concreting, it needs to be removed and the bottom cleaned to ensure the new concrete bonds well with the existing concrete.
Photo 9. Corner with frame structure for the control room and technological switchboards, sewage pipe outlets, and protective pipes at the base. It is clear that the underground utilities exit exactly where the room layout requires them.
Stage 4: ready floor and utilities for the internal equipment of the wet sawdust pellet production line
Photo 10. Pellet line: The hall from the outside: closed enclosure, open gate, and poured concrete driveway. Through the gate, the smooth floor of the belt dryer hall interior is visible. The wide entrance facilitates the delivery of large line units.
Photo 11. Cable entry into the building. Black power cables run in blue conduits, and split cable conduits are installed along the foundation wall. This is the route that will lead power to the distribution boards and line control cabinets.
Photo 12. The troweled floor in the longer section of the hall. The pipe outlet in the floor was protected with foil and tape until installation. The pipe will supply the belt dryer with warm water to dry wet sawdust from 45-50% humidity to 12-15%.
Photo 13. Floor with extended and secured casing pipes and a hole covered with wooden beams. The casing pipes are arranged along the axes of the future receivers: two GRB2 880.264 granulators (each with a capacity of up to 4 t/h) and a granulator buffer tank.
Photo 14. Water connection: galvanized steel pipe with a T-connector at the base and a pipe in a protective casing. Chalk lines on the floor indicate markings. Here, utilities await connection to the equipment: an external dry sawdust silo and the water system inside the production hall.
Investor – Nawrocki Company Cooperation: who is responsible for what during the construction of a pellet factory
The investor builds the facility, and Nawrocki provides the technology and data on which it is based. This principle sounds simple, but in practice it requires constant exchange of information throughout the construction period.
Area | The investor and his contractors | Nawrocki Company |
Production assumptions | Raw material, efficiency, target product, expansion plans | Selection of technologies and machines for the granulation line |
FEED | Providing access to land, buildings and existing utilities | Line layout, loads, requirements for foundations, cable routes and utilities |
Construction project | Designer of building structures and installations | Verification of compliance of drawings with machine requirements |
Execution | Foundations, hall, floor, connections | On-site consultations, answers to contractors' questions |
Staged acceptances | Construction manager, supervision inspector | Checking reserves, anchors and leads before concreting |
Installation and start-up | Access to the hall, utilities, staff for training | Mechanical and electrical installation, commissioning, operator training |
The touchpoints where you most often win or lose
Freezing the layout before designing the foundations. Any change in the machine's position after concreting means breaking up the floor.
A common list of connections. One table with each casing pipe, water connection, and sewer connection, verified by both parties.
Pre-concrete inspection. A short visit or video call with photos of the reserves and channels allows you to catch any errors before the concrete sets in.
Machine foundations in the second stage. The remaining space in the floor (as shown in photos 5–7) allows time to confirm the anchor dimensions from the specific machine documentation.
A single communication channel and change log. Every project change has a date, author, and confirmation from the other party.
That's why Nawrocki commits to the investment long before the first pellet mill is delivered. A well-executed construction phase is the shortest path to a quick and trouble-free line start-up.
Work plan: from FEED to first pellet
The work is divided into ten stages; the photos in this article cover stages 3–6. Each subsequent step begins only after the previous one has been accepted.
Assumptions and concept. The investor specifies the raw material, capacity, and product; Nawrocki Company proposes the line composition and preliminary layout.
FEED. Freezing the layout, calculating loads, and requirements for machine foundations, ducts, cable routes, and utility points.
Construction and detailed design. The Investor's designers transfer FEED requirements to drawings; Nawrocki Company verifies compliance.
Earthworks, foundations, and underground utilities. Foundation footings and walls, sewer systems, manholes, and cable conduits (photos 1–2).
Steel structure and hall cladding. Installation of frames, purlins, sandwich panels, gates, and window strips (photos 3–4).
Floor slab with reserves. Concreting the floor, leaving space for machinery foundations and channels; acceptance of elevations and outlets (photos 5–14).
Machine foundations and anchors. Concreting reserves according to machine documentation, setting anchors or markings, and checking geometry.
Hall installations. Power and switchboards, compressed air, water, dust extraction, lighting, and ventilation.
Granulation line assembly. Granulator, conditioner, cooler, screen, conveyor, and automation setup; electrical and control installation.
Commissioning, training, and acceptance. Cold tests, raw material tests, operator and maintenance training, acceptance protocol.
The most important checkpoints are the acceptance of the terminals before concreting the floor (step 6) and the acceptance of the machine foundations before assembly (step 7). Any error made in these areas is the most difficult to correct later.
FAQ – most frequently asked questions by investors
What is FEED in investing in a granulation line?
FEED (Front-End Engineering Design) is a basic design that defines the machine layout, their loads, and the requirements for foundations, ducts, cable routes, and utilities. Based on this, the structural engineer prepares drawings of the hall and floor.
When to include a granulation line manufacturer in a construction project?
Ideally, this should be done before the foundation and floor design begins. This way, the machine requirements are incorporated into the drawings immediately, rather than as changes made on-site.
Why are empty spaces left in the floor for machines?
Machine foundations are concreted in a separate step, once the exact dimensions of the anchors and the loads of the specific machines are known. This also allows for the separation of machine vibrations from the rest of the floor.
What are the blue pipes sticking out of the floor for?
These are protective pipes for power and control cables. They are routed precisely at the locations of future receivers, so that the floor does not need to be chiseled after pouring.
What should be checked before concreting the floor?
The location and number of casing pipes, the dimensions and elevations of channels and reserves, water and sewage connections, and protecting pipe outlets from contamination. This is best done in conjunction with the technology supplier.
How are the responsibilities divided between the Investor and the Nawrocki Company?
The investor and its contractors are responsible for the building, foundations, and connections. Nawrocki provides the technology and FEED data, verifies the construction documentation, and then installs and commissions the line.
What happened next? Watch the video.
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