2026/10/12
The first step takes place in the crusher, where the task is to break down the fermented, clumpy material into fine powder with a controlled particle size. Decomposed organic material typically has a moisture content of 25% to 50%, is highly viscous, and contains entangled fibers; when traditional screen-equipped crushers encounter such wet material, the screen mesh becomes clogged, preventing discharge and causing the motor to idle or even burn out. The solution offered by the half-wet material crusher is to eliminate the bottom screen and adopt a tandem dual-rotor structure: material is first coarsely crushed by high-speed impact from the upper rotor, then thrown into the lower rotor for further fine pulverization. This creates a dual crushing effect—"hammer pulverizing material" and "material pulverizing material"—resulting in an output particle size of 0.5 to 5 millimeters, which fully meets the requirements for subsequent granulation. While this step does not alter the material's chemical properties, it determines whether the downstream granulation equipment receives "uniform fine powder" or "clumps of varying sizes."
The second step takes place in the fermentation tank, where the task is to provide a continuous supply of oxygen to aerobic microorganisms. Once a compost pile becomes static, oxygen can only penetrate the surface layer; the interior gradually enters an anaerobic state, generating hydrogen sulfide and ammonia. Consequently, the pile temperature fails to rise sufficiently, leaving insect eggs and pathogens alive. The twin-screw turner operates using two parallel, counter-rotating screw rollers, achieving a turning depth of 1.8 to 2.5 meters—an increase of over 40% compared to standard single-screw turners. During the turning process, the twin-screw structure entrains large volumes of air into the material, creating dense aeration channels; this boosts oxygenation efficiency by more than 50% compared to single-screw equipment, maintaining oxygen levels within the optimal 18%–22% range and shortening the fermentation cycle from the traditional 20–25 days to just 12–15 days. Material decomposition uniformity exceeds 95%, providing consistent feedstock for subsequent extrusion granulation.
The third stage takes place in a fertilizer roller press machine, where the task is to impart a permanent physical form to the powder through pressure. Two high-strength, counter-rotating rollers compress the dry powder into dense sheets at ambient temperature, which are subsequently crushed and screened into granules. The entire process requires no added water and involves no temperature increase, with the raw material moisture content needing only to be maintained between 5% and 10%. This dry processing route eliminates the drying and cooling systems essential to wet granulation, reducing overall energy consumption by 30% to 50% compared to wet processes. The core challenge of double-roller press granulation technology lies not in the extrusion action itself, but in the prerequisite of consistently feeding homogeneous powder into the roller gap: if the feed moisture content falls outside the optimal window, wet material slips between the rollers; if particle size fluctuates excessively, the consistency of granule strength drops sharply. The complete configuration of a roller press granulation production line typically includes a metering feed system, a forced feeder, the main roller press unit, a crusher, a multi-stage screening machine, and a packaging machine; the screening stage routes oversized particles back for crushing and recycling while directing qualified granules to the finished product silo, thereby creating a closed-loop process.
