How Does a Hydraulic Sawdust Briquette Press Work?
The Two Main Types of Briquette Presses
Charcoal briquette presses are broadly divided into two categories according to their processing principle: screw extrusion briquette machines and hydraulic extrusion briquette machines. Screw extrusion machines are the mainstream type because of their high efficiency and wide compatibility with different raw materials, while hydraulic machines are preferred for specific feedstocks and small-batch production. Understanding the difference between the two helps a buyer choose the right equipment for the material available on site.
Based on raw material compatibility, briquette machines can also be grouped into wood chip briquette machines, straw briquette machines, and multi-functional biomass briquette machines. Multi-functional models accept several raw materials, offer better cost-effectiveness, and are the most common choice in the market.
Working Principle of the Hydraulic Briquette Press
A hydraulic sawdust briquette press uses an intermittent hydraulic press principle. A hydraulic system generates high pressure and forces the prepared raw material into a molding die, where it is compressed into a dense block. Unlike screw extrusion machines, the hydraulic press does not require continuous heating, and it is suitable for processing raw materials with a slightly higher moisture content of 10 to 14 percent or with a low fiber content, such as peanut shells and rice husks.
The main advantages of the hydraulic press are low equipment wear and a uniform finished product density, because the compression force is applied evenly over the whole cross-section of the block. Its main disadvantage is low production efficiency: a single machine typically produces between 50 and 200 kilograms per hour, which makes it suitable for small-batch processing rather than continuous high-volume production.
Comparison with Screw Extrusion Machines
In a screw extrusion briquette machine, the core working principle is screw pushing, heating softening, and high-pressure molding. Pre-treated raw material enters the feed inlet and is pushed into a narrow molding cavity by the rotating screw shaft. An external heating device controls the temperature at 160 to 200 degrees Celsius, softening and melting the lignin in the material to form a natural binder. The screw shaft applies continuous pressure, extruding the material into a dense rod, which is cut into finished products of a set length. The whole process is continuous, and a single machine can produce 50 to 500 kilograms per hour.
The choice between the two types depends on the raw material and the production volume. Screw machines suit dry, fibrous wood and straw materials and continuous operation. Hydraulic machines suit wetter or low-fiber materials such as peanut shells and rice husks, and they fit small workshops where output requirements are modest.
Raw Material Preparation Requirements
The operating points of a hydraulic briquette maker are similar to those of a wood pellet machine, but the briquette maker has a higher operating threshold, and raw material preparation is the first critical step. The particle size must be 2 to 5 millimeters and the moisture content 8 to 12 percent. This preparation is normally done with a combination of a crusher, a dryer, and a screen.
If the moisture content is too high, the material must be dried; if it is too low, a small amount of water must be sprayed onto the material to adjust it. Otherwise, the operator faces molding difficulties or cracking of the finished product. Checking the moisture regularly during a shift is essential, because the moisture of stored material changes with the weather and the season.
Equipment Debugging and Temperature Control
Before starting the machine, check the gap between the auger shaft and the forming sleeve to make sure there is no jamming, and preheat the heating device to the set temperature of 160 to 200 degrees Celsius before feeding. During production, monitor the condition of the finished product in real time. If the surface is rough, adjust the heating temperature or the raw material moisture content. If jamming occurs, stop the machine immediately and clean it to prevent equipment damage.
Compared with wood pellet mills, briquette presses require stricter temperature control. Excessive heating temperature causes carbonization of the raw material, while insufficient heating means the lignin does not soften enough and the finished product forms poorly. Wood pellet mills do not require forced heating and focus more on adjusting the gap between the pressure roller and the die, which makes them easier to operate in comparison.
Frequently Asked Questions
Q1: What is the working principle of a hydraulic briquette press?
It uses an intermittent hydraulic press principle: a hydraulic system generates high pressure that forces the raw material into a molding die, forming a dense block without continuous heating.
Q2: Which raw materials suit a hydraulic briquette press?
Materials with a slightly higher moisture content of 10 to 14 percent or a low fiber content, such as peanut shells and rice husks, are well suited to hydraulic pressing.
Q3: What is the output of a typical hydraulic briquette press?
A single machine usually produces 50 to 200 kilograms per hour, which makes it suitable for small-batch processing.
Q4: What particle size and moisture content are required for the raw material?
The particle size should be 2 to 5 millimeters and the moisture content 8 to 12 percent, adjusted with a crusher, a dryer, and a screen.
Q5: What temperature is needed for screw extrusion briquetting?
The heating device is usually set to 160 to 200 degrees Celsius to soften the lignin, which acts as the natural binder of the material.
Q6: What should I do if the finished briquettes have a rough surface?
Adjust the heating temperature or the raw material moisture content. Rough surfaces usually mean the lignin is not softening evenly or the material is too dry.
