Lignite Briquetting Press
Lignite, or brown coal, presents unique challenges in fuel processing due to its high moisture content and friable structure. Our Lignite Briquetting Press utilizes high-pressure double-roller technology to compress raw lignite fines into high-density briquettes (ball, pillow, or oval shapes). This process significantly reduces the specific surface area of the coal, improving its thermal stability, increasing its calorific value per unit volume, and making it suitable for long-distance transport and industrial boiler feed.
Unlike bituminous coal, lignite requires specific mechanical handling to achieve a durable bond:
Force-Feeding System: Since lignite is often “fluffy” and low-density, our press features a vertical screw pre-compression feeder. This degasses the material and ensures the roller cavities are consistently filled, preventing “half-balls” or weak structures.
Hydraulic Tonnage Control: The briquetting force is managed by a heavy-duty hydraulic station, allowing operators to adjust the pressure based on the moisture level and binder ratio of the brown coal feedstock.
High-Durability Rollers: To withstand the constant friction of coal fines, our rollers are manufactured from 9Cr2Mo or 65Mn alloy steel, treated for surface hardness and core toughness to prevent fracturing under load.
A briquetting press is the forming core, but for lignite, its performance is dependent on moisture management and material preparation:
Upstream: Crushing & Moisture Adjustment: Raw lignite must be crushed to < 3mm. Because lignite moisture often exceeds 30%, the material is frequently passed through our Rotary Drum Dryers or mixed with dry additives in our double-shaft mixers to reach the optimal pressing moisture (12%–15%).
Downstream: Structural Hardening: Freshly pressed lignite balls are susceptible to breakage if handled immediately. Transitioning them through a Mesh Belt Drying System is essential to reach a stable moisture content of ≤5%, locking in the structural density and reducing the risk of spontaneous combustion during storage.
Briquette Geometry: Standard 30mm–60mm sizes in pillow or round shapes. Custom molds are available for specific gasifier or boiler grate requirements.
Cold Pressing Technology: Operates without the need for high-temperature additives, preserving the fixed carbon content of the lignite.
High Output Consistency: Precision-aligned roller dies ensure a qualification rate of over 95%, minimizing the need for fines recirculation.
Q1: How do you handle the high moisture content typical of raw lignite?
A: Lignite briquetting is a balance of moisture and pressure. If the moisture is too high (above 20%), the “ball” will be soft and fail the drop test. We provide integrated drying solutions to pre-condition the coal before it enters the press, ensuring a high-strength bond.
Q2: What is the maintenance cycle for the rollers in a coal plant?
A: For lignite processing, the alloy rollers typically require maintenance or surfacing after 1,500–2,000 tons of production, depending on the silica content in the coal. Our “quick-change” roller design allows for replacement with minimal line downtime.
Q3: Does the briquetting process increase the risk of spontaneous combustion?
A: Actually, it reduces it. By compressing the lignite into a dense briquette, the internal surface area exposed to oxygen is drastically reduced. When followed by professional drying, the resulting fuel is much safer for storage and transport than loose brown coal fines.
