Pellet wood mill

Types of pellet wood mills

A pellet wood mill is a critical piece of equipment used to manufacture wood pellets. Various wood pellet mills have been developed with different capabilities and applications. Here are the main types.

• Ring die pellet mill: The ring die pellet mills are large-scale machines often used for commercial wood pellet production. They have a vertically or horizontally positioned pelletizing die, with rollers that exert pressure from the outside. Ring die pellet mills have high productivity and stability for continuous operation. Their efficient compression increases the density of the wood pellets. The machines have a geared drive that offers high-torque output, which is ideal for processing hard wood materials. Also, they have die-cooling systems that prevent overheating during the pelletizing process.
• Flat die pellet mill: The flat die pellet mills are used for smaller wood pellet production. They have a horizontally positioned pelletizing die with press rollers mounted on the flat die. Although they produce fewer wood pellets than the ring die pellet mills, flat die mills are popular for their simplicity and ease of use. Also, the pellet mills are cost-effective solutions for wood pellet manufacturers with small production facilities. The pelletizing die can be changed to adjust the size and diameter of the wood pellets.
• Diesel pellet mills: Diesel wood pellet mills use diesel generators as their main power source. They are an ideal wood pellet manufacturing solution for areas with no electric power or unreliable electricity. Diesel wood pellet mills are suitable for processing agricultural and forest residues.
• Flood die pellet mill: Flood die pellet mills are similar to flat die pellet mills, but they have a different die arrangement. The die is cast in a circular flood, and the roller presses the wood material into the die. Flood die pellet mills are used in small-scale wood pellet production.
• Combined pellet mill and briquette press: This type of wood pellet mill can produce wood pellets and briquettes. It has two presses that can be used separately or together to create solid wood fuels. Combined pellet mill and briquette presses are very flexible and suitable for processing several types of wood materials, like hardwood, softwood, and biomass.cleaning.

Specifications and maintenance of pellet wood mills

Specifications

• Power

  The wood pellet mill's power is typically measured in kilowatts (kW) or horsepower (HP). Small-scale mills may have powers ranging from 5.5 kW to 22 kW. Meanwhile, larger industrial mills usually have greater power, around 75 kW to 150 kW or more.

• Die diameter

  The die diameter refers to the circular size of the flat die or ring die used in the wood pellet mill. Various pellet mills produce dies with different sizes. Small machines usually have a die diameter of 100mm to 150mm. Mid-sized pellet mills produce pellets with die diameters of 200mm to 400mm. Larger industrial-scale mills have die diameters up to 1,000mm or even more.

• Pellet size

  The size of wood pellets produced by the wood pellet mill is typically measured by diameter and length. Wood pellets generally have a diameter ranging from 6mm to 12mm, with 8mm as the most common size. Their length can vary from 1.5 times to 3 times the diameter.

• Pellet mill dimensions

  Dimensions of the pellet mill, such as width, depth, and height, are crucial, especially for stand-alone or integrated pellet production units. For example, a small portable pellet mill may measure 1,200mm in width, 1,200mm in depth, and 1,800mm in height. An integrated wood pellet mill may have dimensions of 1,500mm × 2,000mm × 3,500mm.

• Pellet mill weight

  The weight of the wood pellet mill indicates the equipment's construction materials and design. A small wood pellet mill weighs approximately 400kg. Large industrial-scale wood pellet mills are considerably heavier and usually weigh over 1,000kg.

Maintenance

It is critical to regularly maintain the wood pellet mill to ensure stable operation, efficient production, and a longer service lifespan. Here are some routine maintenance tips:

• Clean up timely

  Users need to clean the wood pellet mill as well as its peripheral equipment in a timely manner during pelletizing production. It is necessary to remove residues like wood powder as well as raw material debris. Regularly cleaning can prevent blockage and pollution, ensuring product quality and equipment smoothness.

• Lubricate and refuel frequently

  Users should regularly lubricate the wood pellet mill and its components. Add oil to key parts such as bearings and shafts according to the lubrication requirements. Besides, users should ensure the equipment refueled well, keeping up with the lubrication and fueling maintenance manuals.

• Check and adjust periodically

  Users need to check the wood pellet mill periodically. For instance, they can inspect the fastening state of various components and adjust them as necessary if some parts are loose or need to be adjusted. Besides, users need to check the alignment of transmission parts and adjust the cohesive degree among die plates, blades, and rollers, ensuring appropriate clearances and alignments.

• Pay attention to the ambient

  Users should pay close attention to the surrounding environment of the wood pellet mill. Avoid placing flammable and explosive materials nearby. Besides, users should keep a proper distance between the equipment and external heat sources to reduce the risk of overheating. Furthermore, users can install ventilation and cooling devices for the equipment if necessary, thus ensuring suitable temperature and moisture levels.

Scenarios

The wood pellet mill machine has various applications in different industries. Here are some of the primary uses of wood pellets.

• Energy Production

  Wood pellets are used as a source of energy in biomass power plants. The plants use wood pellets as an alternative to coal. They may also be blended with other fuels to produce heat and electricity. Large-scale wood pellet production is mainly for use in power plants.

• Green Heating Systems

  Wood pellets are applied in residential heating through pellet stoves and boilers. Heating systems that use wood pellets as the main fuel are known as pellet central heating. Wood pellets are also used in underfloor heating and other heat distribution systems in homes and public buildings.

• Animal Bedding

  Pellets produced from compressed sawdust are used as animal bedding for various farm livestock, such as horses, poultry, swine, and ruminants. They have excellent moisture absorption, and their strong capacity reduces bedding costs.

• Transportation and Logistics

  Wood pellet mill suppliers produce pellets since they are easy to handle, transport, and store compared to raw wood. Their high energy density means they occupy less space and are cost-effective to transport.

• Industrial Applications

  Wood pellets are used in different industries as a primary raw material. For example, the paper and pulp industry uses wood pellets as a source of cellulose. The chemical industry uses wood pellets as feedstock for bio-refineries to extract chemicals like bio-oil, ethanol, and acetone.

How to choose pellet wood mills

When planning to purchase a wood pellet mill, buyers should consider the following:

• Correct raw material: Understand the characteristics of the raw material. Different raw materials have different fiber content, moisture content, and density, which affects the selection of the wood pellet mill. For example, agricultural waste such as straw and grass requires a wood pellet mill with high adaptability to fiber for processing.
• Output demand: Determine the production output required. There are small, medium, big, and industrial wood pellet mills. Select an appropriate machine according to the expected production capacity. A suitable wood pellet mill can meet production needs and avoid excessive energy consumption.
• Peleltizing techniques: There are ring die pellet mills and flat die pellet mills. The former is suitable for large-scale production, while the latter is more cost-effective for small-scale production. Choose a pelletizing device according to the business scale.
• Additional equipment: Depending on the needs of the production line, consider selecting additional equipment such as wood shredders, wood dehumidifiers, and wood pellet cooler. Choose suitable assistant machines according to the required processing capacity and technical requirements, and ensure that the assistant machines match the wood pellet mill.
• Quality and service: Products made with a good wood pellet mill will have fewer machine breakdowns and a high pelletizing rate. Consider the quality of the wood pellet mill and the reputation of the manufacturer. In addition, look at the supplier's after-sales service system, including installation support, technical training, and equipment maintenance. A reliable supplier can provide timely support and solutions.
• Budget constraints: Ultimately, buyers must understand their budget and consider the cost of energy, raw material processing, and labor involved in wood pellet processing. Calculate the overall investment and return, and make an informed decision.

Pellet wood mill FAQ:

Q1: What is the difference between a straw pellet mill and a wood pellet mill?

A1: The variable die and press roller are the core components of any pellet mill. Wood has a denser fiber than straw and other agricultural material fibers. Hence, wood requires more space between the die and roller to pass through, making straw pellet mills larger than wood pellet mills.

Q2: What are the two most common types of wood used for pellets?

A2: The softwood is found in evergreen trees, such as pines, firs, and spruces. Hardwoods come from trees that shed their leaves every year, such as oak, maple, and hickory.

Q3: What kind of wood should be avoided when making wood pellets?

A3: Try to avoid making pellets from low-quality, resinous, or high-lignin wood, such as pine or sweetgum. Such wood burns dirty and produces a large amount of ash, which is a burden for the stove and shaker.