Straw Wood Board Pellet Making Plant in Bulgaria

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Project Concept Seen from the First Conversation

This 3.5–4t/h straw wood board pellet making plant in Bulgaria didn’t start with a fixed design. The first inquiry was actually quite open-ended. The client sent a few photos of stacked straw bales and leftover wood boards from a dismantling operation, and asked a very direct question: “Can these be processed together without building two separate lines?”

That question already told us a lot.

In regions like Bulgaria, raw materials are often fragmented—straw from agriculture, and wood residues from small-scale board processing or demolition. Transporting these materials long distances doesn’t make economic sense, so combining them into one flexible pelletizing system becomes the practical approach.

The final idea was not just a machine purchase. It became a small-scale biomass fuel plant with a stable output target, designed around mixed feedstock behavior rather than a single uniform material.

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Raw Materials

During the early technical review, raw material characteristics were discussed in detail. The moisture content difference between straw and wood board residues was one of the key design considerations.

Below is a simplified breakdown of the main raw materials used in this straw wood board pellet making plant in Bulgaria:

In practice, the material is not always perfectly clean. During unloading, workers manually remove visible impurities such as metal wires or plastic fragments. This step may look simple, but it helps protect downstream equipment significantly.

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Equipment Configuration

Instead of listing everything as isolated machines, the system is better understood as interconnected functional sections.

1. Raw Material Handling & Pre-treatment

• Manual unloading and initial sorting
• Belt conveyors for continuous transfer
• Feeding bins for temporary storage
• Preliminary impurity removal

This stage is less about automation and more about stabilizing feedstock before mechanical processing.

2. Size Reduction Section

• Straw and wood board materials are first processed through a hammer-type crusher system
• Oversized pieces are reduced to manageable particle sizes
• Material is then directed into fine grinding if needed

Dust generation at this stage is noticeable. In practice, the airflow design and suction points make a big difference in keeping the workshop environment acceptable.

3. Fine Grinding Section

• Secondary grinding ensures uniform particle size
• Material is prepared for pelletizing
• Pneumatic or enclosed conveying reduces dust leakage

This stage directly impacts pellet quality. If particle size is inconsistent, pellet density and durability will fluctuate.

4. Pelletizing Section

• Multiple wood pellet mills operate in parallel
• Continuous feeding system ensures stable input
• Ring die extrusion compresses biomass into dense pellets

Operators usually spend time adjusting:

• Feed rate
• Moisture balance
• Die temperature

Small adjustments here often show immediate effects on pellet hardness.

5. Cooling and Screening

• Fresh pellets exit at elevated temperature
• Natural or forced cooling reduces temperature before storage
• Vibrating screen removes fines and reintroduces them into the system

This closed-loop approach helps reduce material waste.

6. Packaging and Storage

• Finished pellets are transported to storage area
• Bagging system used depending on customer requirements
• Warehouse designed to avoid moisture exposure

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Main Equipment List

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Production Workflow

The actual operation sequence of this straw wood board pellet making plant in Bulgaria can be summarized as:

1. Raw materials are unloaded and roughly sorted
2. Straw and wood residues are conveyed into the crushing system
3. Materials are reduced in size through primary and secondary grinding
4. Fine particles are temporarily stored and buffered
5. Controlled feeding sends material into pellet mills
6. Pellets are formed through mechanical compression
7. Hot pellets are cooled to stable condition
8. Screening removes fines and recycles them
9. Final pellets are packaged or stored in bulk

During trial runs, operators often adjust the balance between straw and wood input. Too much straw can reduce pellet durability; too much wood board material may increase density but affect flowability. Finding the right ratio is part of normal operation tuning.

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Installed Capacity and Operating Conditions

• Designed capacity: 3.5–4 t/h
• Annual production: ~30,000 tons
• Working days: ~330 days/year
• Operation mode: 2 shifts per day
• Total workforce: 8 personnel

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Utilities and Consumption

Water usage remains low and is mainly for domestic purposes. No significant process wastewater is generated.

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Site Layout Considerations

The biomass pellet project was installed within an existing facility, so layout planning focused heavily on material flow efficiency rather than new construction.

A practical observation during design was airflow direction. Pellet production generates fine dust, especially during crushing and screening. Positioning the office area on the side opposite to prevailing airflow helps reduce dust exposure for staff.

The general layout follows:

• Raw material zone → processing zone → pelletizing zone → finished product warehouse
• Straight-line flow to minimize material handling distance
• Separation between dusty areas and administrative areas

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Environmental Handling

Instead of complex systems, the project uses straightforward but effective measures:

• Bag filter systems at key dust generation points
• Enclosed conveyors to limit dust escape
• Local exhaust ventilation near crushers and grinders
• Proper collection and reuse of captured dust back into the process

Solid residues such as impurities and rejected particles are collected and handled separately.

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Equipment Investment Reference

For this straw wood board pellet making plant in Bulgaria, the equipment investment was approximately:

• USD 180,000 (equipment only)

This includes crushing, grinding, pelletizing, cooling, conveying, and dust control systems. The final cost varies depending on automation level and configuration details.

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Shipping Arrangement

All main equipment for this biomass pellet plant project was shipped from China via sea freight.

• Departure port: Qingdao Port
• Destination port: Port of Varna (Bulgaria)

Varna is commonly used for industrial imports entering Bulgaria due to its access to inland transport routes.

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Practical Notes from Installation and Commissioning

During commissioning, the first few batches of pellets required adjustment. Straw content was slightly higher than expected at the beginning, which resulted in pellets that were lighter and less compact.

After adjusting:

• Raw material mixing ratio
• Moisture conditioning
• Feed consistency into pellet mills

The system stabilized and reached continuous output within a short period.

One small but important lesson from this straw wood board pellet making plant in Bulgaria project: mixed raw material systems require operators to “feel” the process rather than rely only on fixed parameters.

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Market Potential in Bulgaria

Biomass pellet demand in Bulgaria is supported by:

• Growing interest in renewable heating
• Availability of agricultural residues
• Small-scale industrial energy users
• Cost pressure from traditional fuels

Projects like this straw wood board pellet making plant in Bulgaria fit well into the local energy structure because they rely on readily available materials and relatively low operating complexity.

For investors, the advantage lies in:

• Stable raw material supply
• Moderate equipment investment
• Localized demand without heavy export dependency

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A Note from the Engineering Side

Projects of this scale tend to succeed not because of any single machine, but because the system matches the raw material reality. Straw behaves differently from wood, and wood board residues can vary depending on their origin.

When both are combined thoughtfully, the production line becomes more resilient. That’s usually the point where clients start to see consistent output rather than intermittent operation.

RICHI Machinery’s role in such projects typically goes beyond supplying equipment—we often stay involved in layout planning, process matching, installation guidance, and operator training. In mixed-material pellet projects especially, this kind of support tends to make a noticeable difference during startup and stabilization phases.