Trough-Type Compost Turners: Mechanized Core for Efficient Aerobic Composting

In the era of emphasizing circular economy and sustainable waste management, trough-type compost turners have emerged as indispensable mechanized equipment in large-scale organic waste treatment systems. These specialized machines operate by traversing along fixed rails positioned above elongated fermentation troughs, leveraging rotating drums equipped with robust teeth or paddles to perform a suite of critical functions—lifting, breaking, mixing, and aerating diverse organic materials such as livestock manure, municipal sludge, crop residues, and even agricultural by-products like oil palm empty fruit bunches. By optimizing aerobic decomposition conditions, they enable the rapid and consistent conversion of organic wastes into stable, nutrient-rich compost, making them a cornerstone in organic fertilizer production, environmental waste treatment, and sustainable agriculture sectors.

The working principle of trough-type compost turners is a sophisticated integration of mechanical motion and biological decomposition, with each functional step meticulously designed to enhance composting efficiency. Aeration, the fundamental prerequisite for successful aerobic composting, is achieved through the machine’s rotating drum. Equipped with sharp, wear-resistant teeth or curved paddles, the drum penetrates deep into the compost pile—often reaching 1 to 1.8 meters in depth—lifting and turning over bottom-layer materials that are prone to oxygen depletion. This process fully exposes the organic matter to atmospheric oxygen, which is essential for fueling the metabolic activities of aerobic microbes (such as bacteria and fungi). By maintaining sufficient oxygen levels (typically 15-20% within the pile), the turners effectively prevent the formation of anaerobic environments that produce foul-smelling gases like hydrogen sulfide and methane, ensuring a odor-controlled composting process.

Mixing and breaking are equally crucial functions that guarantee uniform compost quality. During operation, the high-speed rotation of the drum (usually 25-40 revolutions per minute) shatters dense clumps and hard lumps in the compost pile, which are common in materials like fresh manure or dewatered sludge. Simultaneously, the turning action thoroughly blends different sections of the pile, eliminating uneven distribution of moisture (wet and dry spots) and temperature (hot and cool zones). This uniform mixing ensures that all organic particles are exposed to the optimal composting environment, avoiding incomplete decomposition caused by local deficiencies in oxygen, moisture, or nutrients. For instance, when processing a mixture of high-carbon crop straw and high-nitrogen poultry droppings, the turner ensures the carbon-to-nitrogen ratio (C/N) is evenly maintained at the ideal range of 25:1 to 30:1, a key factor in accelerating microbial decomposition.

Material movement and process control further enhance the continuity and efficiency of the composting process. As the trough-type turner travels along the rails at an adjustable speed (0.5-1.5 meters per minute), the rotating drum pushes the compost material backward slightly, ensuring that every particle in the long trough is sequentially turned and mixed. This continuous material circulation, combined with aeration and mixing, creates a stable composting environment where temperature is regulated between 55-65°C—a range that effectively kills pathogens, weed seeds, and insect eggs while promoting the decomposition of organic matter into humus. Moreover, many advanced models are equipped with intelligent monitoring systems that track real-time temperature and moisture levels in the pile. When moisture content deviates from the optimal 55-60%, the integrated sprinkler system automatically supplements water, further refining process control. Thanks to these optimized mechanisms, trough-type turners can shorten the composting cycle significantly, reducing the traditional 45-60 day process to just 7-10 days for mature compost production.

The applications of trough-type compost turners are diverse and far-reaching, addressing critical needs across multiple industries. In organic fertilizer production plants, they are widely used to convert livestock manure (cow dung, pig manure), poultry droppings, and crop residues (wheat straw, corn stover) into high-quality organic fertilizers, which enhance soil fertility and reduce reliance on chemical fertilizers. In environmental protection, they play a vital role in treating municipal sludge and food waste—processing these potentially polluting wastes into usable compost, thereby reducing landfill pressure and mitigating environmental pollution. In horticulture and landscaping, the compost produced with their assistance is used to improve soil structure in gardens, green belts, and horticultural fields, promoting healthy plant growth. Additionally, they find applications in biomass energy production, where they prepare organic materials for subsequent energy conversion processes, and in mushroom cultivation, facilitating the fermentation of substrate for agaricus growth.

With their efficient performance, odor control capabilities, and versatile applications, trough-type compost turners have become an essential tool in advancing sustainable waste management practices. By bridging the gap between organic waste and valuable compost, they not only contribute to environmental protection but also support the development of a circular economy, making them indispensable in the global pursuit of green and sustainable development.

The Critical First Step in a Value-Adding Chain

The trough-type compost turner is a foundational piece of equipment that embodies advanced fermentation composting turning technology. It is specifically designed to execute trough-type aerobic fermentation composting technology, providing the controlled environment necessary for rapid and uniform decomposition. As a highly efficient agriculture waste compost fermentation machine, it accelerates the organic fertilizer fermentation process, transforming raw waste into stable, mature compost.

This machine is a core component within the broader suite of equipments required for biofertilizer production. While a hydraulic trough compost turner excels in this controlled trench system, other site layouts may utilize a self propelled compost production machine or a windrow compost turning machine for open windrows. The high-quality compost produced by these systems serves as the primary organic feedstock. To create a market-ready product, this compost is often further processed—it can be blended with other nutrients and shaped into uniform granules using equipment like a rotary drum granulator in subsequent processing stages. Thus, the turner’s role is to create the essential raw material that feeds the entire organic fertilizer manufacturing value chain.Ultimately, by ensuring efficient and hygienic decomposition, trough-type turners are not just waste processors; they are the vital first-stage enablers of a sustainable industry that converts organic waste into valuable soil amendments and biofertilizers.

Highly Efficient Slow-Release! 15T/Hour Sulfur-Coated Urea Production Line

The sulfur-coated urea production line focuses on the slow-release modification needs of conventional urea. Through a closed-loop process of “urea pretreatment – melt sulfur coating – cooling and solidification – finished product grading,” it achieves large-scale production of 15 tons/hour of sulfur-coated urea. The finished granules use urea as the core and sulfur as the slow-release coating layer, combining the advantages of long-term nutrient release and environmental protection and energy saving. It is suitable for large-scale planting scenarios such as grain crops and cash crops, significantly improving fertilizer utilization.

Production Line Configuration and Core Details

I. Urea Pretreatment Unit: Laying the Foundation for Sulfur Coating

(I) Raw Material Storage and Quantitative Feeding

Urea Raw Material Silo: Equipped with two 50m³ conical raw material silos (total volume 100m³), made of carbon steel with an anti-corrosion coating. The silo cone angle is 65°, and a vibrator and star-shaped unloader are installed at the bottom to prevent urea granule bridging and blockage. The raw material silo is equipped with a pulse dust collector at the top to collect feed dust. The dust emission concentration is ≤10mg/m³, meeting environmental protection standards.

Precision Feeding System: Two frequency-controlled belt feeders (model DTⅡ-500) are used, each with a feeding capacity of 7.5-8 tons/hour. Combined operation meets the production capacity requirement of 15 tons/hour. The feeders are equipped with weight sensors to provide real-time feedback on the feed amount. The speed is adjusted via a PLC system, with a batching error ≤±0.5%.

(II) Urea Screening and Preheating

Grading and Screening Machine: One Φ1.8×6.0 meter drum screen is used, employing a single-layer screen (pore size 2.5-4.5mm) to screen out uniformly sized urea particles (removing <2.5mm fragments and >4.5mm large pieces), ensuring uniform sulfur coating. Non-conforming particles are conveyed to a crusher via a return conveyor belt for crushing and recirculation, achieving a material utilization rate of 99% and a screening efficiency of 18 tons/hour.

Low-temperature preheater: A Φ1.5×12 meter drum preheater is used, employing indirect steam heating to raise the temperature of urea particles from room temperature to 40-50℃. Preheating reduces the surface tension of the urea particles, facilitating the adhesion of the sulfur coating layer, while preventing rapid solidification of sulfur due to low-temperature urea, which would affect the continuity of the coating. The preheater is equipped with a temperature sensor, ensuring precise temperature control with an error ≤±2℃.

II. Core Sulfur Coating Unit: Key to Slow-Release Layer Formation

(I) Sulfur Melting System

Melting Tanks: Three 10m³ stainless steel melting tanks are configured (2 in use, 1 as standby), using electric heating + circulating heat transfer oil to heat solid sulfur (particle size ≤5mm) to 125-135℃, melting it into liquid sulfur (viscosity ≤0.02Pa・s). The melting tank is equipped with a level sensor and an automatic replenishment device to maintain a stable liquid level. A single tank has a melting capacity of 6 tons/hour, meeting coating requirements.

Sulfur transfer pumps: Three gear-type insulated transfer pumps (temperature resistance ≥150℃) are used to pressurize and transfer liquid sulfur to the coating machine. The transfer pressure is controlled at 0.3-0.5MPa, and the flow rate is adjustable from 300-500kg/hour (sulfur addition accounts for 8%-12% of the total urea content, adapting to different slow-release cycle requirements). The transfer pipeline adopts a double-layer insulation design, with the outer layer wrapped in rock wool to prevent sulfur from cooling, solidifying, and clogging the pipeline.

(II) High-efficiency coating machine

Core equipment selection: Two Φ2.2×8.0 meter roller-type coating machines (7.5 tons/hour per machine) operate in parallel, with a total capacity of 15 tons/hour. The inner wall of the coating machine’s drum is lined with high-temperature and wear-resistant plates, and a spiral layout with lifting plates drives the material in a “tumbling-spraying-rolling” motion, ensuring that each urea granule is evenly contacted with liquid sulfur.

Coating process details: Liquid sulfur is evenly sprayed onto the surface of the urea granules inside the drum through atomizing nozzles (0.8mm orifice diameter), with an atomization pressure of 0.4MPa, forming a uniform sulfur film layer with a thickness of 0.1-0.3mm. The coating machine is equipped with a variable frequency speed control system, allowing the drum speed to be adjusted within the range of 8-15 r/min, controlling the material residence time to 3-5 minutes to ensure a dense, gap-free coating layer.

Auxiliary coating optimization: Depending on requirements, 0.5%-1% paraffin wax or asphalt can be added as a sealant, sprayed synchronously with the sulfur through an independent atomization system to fill the pores in the sulfur film layer, further enhancing the slow-release effect and extending the nutrient release period to 3-6 months.

III. Post-processing and Curing Unit: Ensuring Finished Product Quality

(I) Cooling and Curing

Counter-flow Cooler: Equipped with two Φ1.8×15 meter drum coolers (each with a processing capacity of 8 tons/hour), using counter-flow cooling with ambient temperature air to rapidly reduce the temperature of the coated particles from 100-110℃ to below 30℃. The cooler has a built-in air guide device to enhance heat exchange efficiency. The cooling time is controlled within 10 minutes to ensure complete curing of the sulfur coating layer, achieving a hardness of over 2.0MPa and preventing damage.

Cooling Air Treatment: A small amount of sulfur dust carried by the cooling air is collected by a pulse dust collector with a collection efficiency of 99.5%, avoiding environmental pollution. The collected sulfur dust can be recycled back to the melting tank for reuse.

(II) Grading and Anti-caking Treatment

Finished Product Screening: Two Φ1.5×4.0 meter vibrating screens are used, employing a double-layer screen design. The upper screen (5.0mm aperture) separates oversized agglomerated particles, while the lower screen (2.0mm aperture) screens qualified finished products, achieving a qualified particle pass rate of 98%. Unqualified particles are crushed and returned to the pretreatment stage, resulting in a material utilization rate of 99%.

Anti-caking Spraying: A small spraying device is added after screening to spray 0.1%-0.2% of an anti-caking agent (such as talc suspension) onto the surface of the finished particles. Through natural mixing during the belt conveyor process, the agent adheres evenly to the particle surface, preventing agglomeration during storage.

IV. Finished Product Storage and Packaging Unit: High-Efficiency Output

Finished Product Warehouse: Equipped with 3 x 100m³ finished product warehouses (total volume 300m³), featuring a sealed design and equipped with dehumidification and ventilation devices to maintain relative humidity ≤60% and prevent finished products from absorbing moisture. A quantitative unloading device is installed at the bottom of the warehouse for continuous and stable discharge.

Automated Packaging: Utilizes 4 dual-station automatic packaging scales (120 bags/hour per scale), supporting rapid switching between 25kg and 50kg specifications, with a measurement error ≤±0.2kg. The packaging machine is equipped with a dust cover and automatic sewing device to reduce dust emissions. Packaged finished products are transferred to the finished product stacking area via belt conveyor. The entire process is automated, minimizing manual intervention.

V. Environmental Protection and Intelligent Control Unit: Stable and Environmentally Friendly Operation

(I) Environmental Treatment System

Waste Gas Treatment: The small amount of sulfur vapor generated by the melting tank and coating machine is recovered by a condensation recovery device. Uncondensed waste gas is purified by an activated carbon adsorption tower before being discharged. The waste gas emission concentration complies with the “Integrated Emission Standard for Air Pollutants”. Wastewater Treatment: Wastewater from the production line cleaning process is treated in an oil separator and sedimentation tank before being recycled for equipment cleaning, achieving zero wastewater discharge.

(II) Intelligent Control System: An integrated PLC central control system with a touchscreen interface monitors the operating parameters of each piece of equipment in real time (sulfur melting temperature, coating machine speed, cooling temperature, feed rate, etc.), supporting automatic fault alarms and data recording (storage period ≥ 90 days). The system supports remote monitoring and operation, facilitating real-time monitoring of production status by management personnel.

Key equipment (melting tank, coating machine, cooler) is equipped with safety interlock devices, such as automatic power-off for overheating of the melting tank and automatic shutdown for overload of the coating machine, ensuring production safety.

Core Advantages and Application Value of the Production Line: High and Stable Production Capacity: The dual-machine parallel configuration achieves an hourly output of 15 tons and an annual capacity of 120,000 tons (calculated based on 300 days of operation per year and 8 hours per day), meeting the needs of large-scale production. Excellent slow-release effect: The dense and uniform sulfur coating allows for flexible adjustment of the nutrient release cycle (3-6 months), increasing fertilizer utilization by 30%-40% compared to conventional urea, while reducing nutrient loss and environmental pollution.

Environmentally friendly and energy-saving: A fully sealed design and dust recovery system result in low pollutant emissions; the preheater and melting tank utilize energy-saving heating technology, reducing energy consumption by 10% compared to conventional production lines.

Enabling Enhanced-Efficiency Fertilizers Through Specialized Production

This sulfur-coated urea production line represents a highly specialized segment within the broader fertilizer manufacturing industry. It focuses on creating a value-added, controlled-release product from a single nutrient source, demonstrating the sophistication possible with modern npk fertilizer production technology.

While this line produces a specialized single-nutrient product, it shares its industrial ecosystem with the equipment used for the manufacturing of npk fertilizer. The production of traditional compound fertilizers often relies on a complete npk fertilizer manufacturing process that begins with precise blending using an npk blending machine or a bulk blending fertilizer machine. The blended mixture is then shaped using an npk fertilizer granulator machine employing advanced npk granulation machine technology as part of a suite of npk fertilizer granulator machine equipment. The scale and efficiency of such integrated systems determine a plant’s overall NPK compound fertilizer production capacity. Therefore, a sulfur-coating line is a complementary technology, adding a specific functionality that works alongside, rather than replaces, conventional bulk blending and granulation systems.Ultimately, the ability to offer both conventional NPK blends and advanced coated products allows manufacturers to serve a wider market, from basic nutrient supplementation to precision, efficiency-focused agriculture.

We warmly welcome people from all walks of life to visit, guide, and discuss business with us, and work together to create a new future for green agricultural development!

Steel structure enables efficient granulation

A dedicated extrusion granulation production line has been successfully put into operation in Colombia, enabling high-efficiency granulation through steel structures!

In May 2025, Zhengzhou Huaqiang Heavy Industry Technology Co., Ltd. completed the installation and commissioning of a steel-structured extrusion granulation production line tailored for a Colombian client, officially entering the stage of large-scale production. This production line, with its steel structure plant layout as its core adaptation, integrates the entire chain of processes including mixing, lifting, feeding, granulation, screening, and packaging. With its robust configuration of two 3.0-type extrusion granulators, compact and efficient space utilization, and stable and reliable operation, it has become another benchmark project for Chinese granulation equipment in the South American market, providing local fertilizer producers with a highly adaptable and cost-effective mass production solution.

Production Line Configuration and Core Equipment Analysis

The entire steel-structured extrusion granulation production line is built around a closed-loop logic of “precise pretreatment – efficient granulation – quality control – finished product output.” Equipment selection is closely matched to the load-bearing capacity and spatial layout of the steel-structured plant, with each unit seamlessly integrated. This ensures production efficiency while maximizing plant space utilization, fully meeting the large-scale production needs of Columbia’s clients.

Raw Material Pretreatment and Conveying Unit: Laying a Solid Foundation for Uniform Granulation

Efficient Mixing Process: The production line uses a 2000-type disc mixer as the core of raw material pretreatment. This equipment features a large-diameter disc design with a mixing diameter of 2.0 meters, providing ample volume for batch mixing of multi-component raw materials. The mixing blades adopt a spiral layout, coupled with a variable frequency speed control system (speed range 10-25 r/min), which can flexibly adjust the mixing intensity according to the raw material moisture and ratio, ensuring sufficient convection and shearing of nitrogen, phosphorus, and potassium main raw materials and trace elements. The mixing uniformity error is ≤2%, providing a uniform raw material foundation for subsequent granulation. The equipment features wear-resistant lining plates to extend its service life and is equipped with an automatic unloading device to ensure continuous production.

Stable Lifting and Feeding: The mixed raw materials are vertically conveyed to subsequent stages via a 315-type bucket elevator (10 meters). This elevator is optimized for the vertical space of steel structure plants, with a small footprint and high load-bearing capacity. It uses a plate chain drive structure, ensuring smooth and noiseless operation, with a conveying efficiency of 6 tons/hour. Its excellent sealing effectively prevents the raw materials from becoming damp, contaminated, or generating dust during lifting. The lifted raw materials then enter a 2000-type disc feeder. The feeder uses frequency conversion control and automatic material level monitoring technology to precisely regulate the feed rate, ensuring uniform feeding to the two extrusion granulators. This avoids fluctuations in granulation quality or equipment overload caused by uneven feeding, achieving precise matching between raw material supply and granulation rhythm.

Core Granulation Unit: Dual-Machine Parallel Operation Enhances Efficiency

The core equipment of the production line consists of two 3.0-type extrusion granulators. This model is a mature product developed by Huaqiang Heavy Industry for medium to large-scale production capacity needs. It is specifically optimized for the load-bearing standards of steel-structured plants, featuring a compact structure and reasonable weight distribution, perfectly adapting to the load-bearing limitations of the plant. The granulator adopts a high-strength double-roller extrusion design with a roll diameter of 300mm and a roll width of 250mm. The extrusion pressure (6-18MPa) is precisely controlled through a hydraulic pressurization system, adapting to the granulation needs of organic fertilizer and compound fertilizer raw materials with different moisture content (28%-35%) and different compositions.

The granulator rollers are made of high-chromium alloy, with a hardness exceeding HRC62 after quenching. This results in three times the wear resistance compared to ordinary materials, extending the service life to over 10,000 hours. The roller surface features a customized anti-slip texture design, enhancing material gripping force and effectively preventing slippage. The granulation rate remains consistently above 93%, with uniform particle size controlled at 3-5mm and a compressive strength of 2.7MPa. The granules are not prone to pulverization, fully meeting the needs of Colombian agriculture for fertilization and long-distance transportation. Two granulators can operate in parallel, each with a capacity of 2.5 tons per hour. Combined operation achieves a total capacity of 5 tons per hour and a daily capacity of 120 tons, significantly improving customer production efficiency.

Grading and Finished Product Output Unit: Strict Quality Control and Efficient Delivery

Precise Screening and Recycled Material Utilization: Granulated particles are transported via a conveyor system to a 1.2×4.0 meter drum screen. This equipment is optimized for the lateral space of steel structure plants, maximizing floor space and screening efficiency. The screen uses a single-layer high-precision screen design, with screen apertures customizable to customer needs. Grading and screening are achieved through uniform drum rotation (18 r/min). Qualified particles (3-5 mm diameter) achieve a 98% pass rate, while substandard particles (too coarse or too fine) are returned to the raw material mixing front end via a 5-meter return conveyor belt, re-entering the granulation process. Material utilization reaches 99%, effectively reducing production costs. The screen is equipped with an automatic screen cleaning device, which cleans material adhering to the screen surface in real time, preventing screen blockage and ensuring stable screening efficiency. The equipment features a sealed enclosure design, reducing dust pollution and meeting local environmental protection requirements.

Finished Product Storage and Automated Packaging: Qualified granules are conveyed to the finished product warehouse via a 7-meter belt conveyor for temporary storage. The warehouse is a custom-designed steel-structure plant with a sealed structure and a dehumidification and ventilation system to effectively prevent fertilizer from absorbing moisture and clumping, ensuring product storage stability. The warehouse capacity can meet the storage needs of 5 consecutive hours of full-load production. Material level sensors are installed inside the warehouse to provide real-time inventory feedback, facilitating customers to rationally plan their shipments. The packaging process utilizes an automatic packaging scale that supports rapid switching between various packaging sizes such as 25kg and 50kg. Employing gravity-based metering principles and high-precision sensors, the metering error is ≤±0.2kg, with a packaging speed of up to 80 bags/hour. This enables rapid, quantitative packaging of finished products, and, in conjunction with the subsequent transfer system, efficiently completes finished product warehousing and shipping.

Core Advantages of the Production Line and its Compatibility with Steel Structures

Exclusive Optimized Design for Steel Structures: All equipment in the production line is customized and optimized for the spatial dimensions, load-bearing standards, and ventilation conditions of steel structure workshops. The equipment layout is compact and rational, requiring only 450 square meters of space, saving 25% compared to traditional production lines. Simultaneously, optimized equipment maintenance access adapts to the maintenance needs of steel structure workshops, ensuring convenient and efficient operation and maintenance.

Stable, Reliable, and Highly Adaptable: Core equipment uses high-temperature, wear-resistant, and corrosion-resistant materials, adapting to the tropical climate of Colombia and effectively resisting the impact of high temperature and humidity. The 3.0-type extrusion granulator can flexibly adapt to various materials such as organic fertilizer, compound fertilizer, and bio-organic fertilizer, supporting rapid switching between different formulations to meet the diverse agricultural fertilization needs of the region.

High Efficiency, Energy Saving, and Cost-Effectiveness: The entire production line uses energy-saving motors and optimized process design, reducing energy consumption by 13% compared to conventional production lines with the same capacity. The equipment has a high degree of modularity, short installation cycle, and standardized design for key components. Wear parts are highly interchangeable. The company provides comprehensive spare parts supply and overseas technical guidance services, significantly reducing customers’ subsequent operation and maintenance costs. The successful commissioning of the Colombian steel extrusion pelletizing production line not only demonstrates Huaqiang Heavy Industry’s comprehensive strength in high-end pelletizing equipment R&D, customized steel structure design, and overseas project implementation, but also provides efficient and stable equipment support for the modernization of agriculture in South America. In the future, Huaqiang Heavy Industry will continue to focus on the production conditions and needs of different regions, optimize product performance and service solutions, and provide global customers with more competitive customized solutions, allowing “Made in China” to shine even brighter in the international market.

Expert Application of Dry Granulation Technology

This successful Colombian project showcases the practical application of a specialized extrusion granulation line, expertly engineered for a steel structure environment. It is a prime example of a specific fertilizer granulation technology being deployed to meet localized production needs efficiently.

The core of this line is the fertilizer compactor performing fertilizer granules compaction, which falls under the category of dry granulation processes. This method is one of several fertilizer granulation processes available to manufacturers. In the broader context of the npk manufacturing process, producers can choose between different types of fertilizer processing machine technologies. For dry compaction, a roller press granulator production line is typically used. For wet granulation, a rotary drum granulator would be the appropriate choice. Each technology represents a different pathway within the overall suite of fertilizer granulation technology, allowing producers to select the optimal method based on raw material properties and final product requirements. this project underscores the importance of matching the right granulation technology to the specific physical, chemical, and economic constraints of the production site, ensuring both operational efficiency and product quality.

We warmly welcome people from all walks of life to visit, guide, and discuss business with us, and work together to create a new future for green agricultural development!

Why does wet granulation dominate the production of high-quality organic fertilizers?

In the field of high-quality organic fertilizer production, wet granulation has become the dominant choice due to its precise adaptation to raw material characteristics and stable assurance of finished product quality. Compared to dry granulation, it effectively addresses the core needs of organic fertilizer raw materials, which are complex and require a balance between nutrient retention and molding effect. This is the key to its dominant position.

Organic fertilizer raw materials are mostly animal manure and fermented crop residues, with significant fluctuations in moisture content and composition. In organic fertilizer production lines, wet granulation can precisely control moisture to create suitable viscosity in the raw materials, allowing for efficient molding without excessive binders. Both rotary drum granulators and disc granulators operate based on this principle. This reduces costs and avoids the impact of external additives on the purity of organic fertilizers, ensuring the natural safety of the product.

High-quality organic fertilizers require uniform particle size, moderate strength, and good water solubility. Wet granulation, through a continuous process of mixing, crushing, and granulation, ensures thorough mixing of raw materials and even distribution of nutrients; the formed granules have a dense structure, making them easy to store and transport without breaking; and the appropriate moisture content also improves the water solubility of the granules, accelerating nutrient release and better meeting the absorption needs of crops.

From a production feasibility perspective, wet granulation technology is mature and suitable for large-scale organic fertilizer production lines. Wet granulation lines composed of rotary drum granulators and disc granulators can adapt to different raw materials by adjusting moisture and rotation speed, offering strong flexibility; and the granulation process produces less dust, and when combined with subsequent drying and screening steps, it can achieve clean production, meeting environmental protection requirements.

Large wheel compost turning machine: The high-efficiency engine of organic fertilizer production lines

In modern organic fertilizer production, a complete production line is transforming traditional composting with its systematic operation. Each link in this line has its specific function, and the large wheel compost turning machine, with its unique working method, is a crucial guarantee for the efficient operation of the entire system.

In open windrow fermentation fields, the large wheel compost turning machine demonstrates excellent adaptability. Its unique large-diameter turning discs can penetrate deep into the material, achieving thorough turning and mixing. Compared to traditional equipment, it has a larger processing capacity and more uniform turning, creating ideal conditions for aerobic fermentation.

Once the initially composted material enters the processing area, the new type organic fertilizer granulator begins to play a key role. Through unique molding technology, it transforms powdery organic raw materials into uniform and plump granules. This transformation not only improves the marketability of the product but also solves the dust problem during organic fertilizer application, facilitating subsequent mechanized fertilization.

From the raw material processing by the large wheel compost turning machine to the finished product forming by the new type organic fertilizer granulator, the entire organic fertilizer production line demonstrates the systematic advantages of modern agricultural equipment. Each link is closely connected, jointly constructing an efficient conversion channel from organic waste to high-quality fertilizer.

This complete organic fertilizer production line not only improves production efficiency but also represents a modern direction for resource recycling. It transforms various organic wastes into valuable resources that nourish the land through systematic treatment, playing an increasingly important role in sustainable agricultural development.

Fertilizer granules compaction technology: The core optimization engine of bio-organic fertilizer production lines

In bio-organic fertilizer production lines, fertilizer granules compaction technology is not merely a single granulation step, but a core optimization process that runs through the entire process from raw material processing to finished product. Its precise integration with various bio-organic fertilizer equipment directly determines the efficiency, quality, and environmental performance of the production line, making it a critical technological support for bio-organic fertilizer production.

Adaptation in the pretreatment stage is fundamental to the successful implementation of the process. Fermented organic fertilizer raw materials need to be processed by crushing and screening equipment. The requirements of the fertilizer granules compaction technology regarding raw material particle size and moisture content drive the precise control of the pretreatment equipment—ensuring that the raw materials are refined to a particle size suitable for extrusion, and the moisture content is controlled within the optimal range of 30%-40%, avoiding problems such as roller sticking and uneven molding.

In the core granulation stage, this technology works efficiently with the fertilizer compaction machine. The fertilizer compaction machine receives the pre-treated raw materials and completes the molding process by setting parameters such as extrusion pressure and roller speed. Compared with other processes, it does not require the addition of extra binders, ensuring particle hardness and molding rate while maximizing the retention of nutrients in the raw materials. The resulting granules are also better suited for subsequent cooling and screening equipment.

In subsequent stages, the advantages of the process become even more apparent. The extruded granules have high uniformity, which improves the heat exchange efficiency of the cooling equipment, reduces the sorting load of the screening equipment, and ensures the smooth operation of the production line.

Efficient operation of bio-organic fertilizer equipment: The crucial role of the fertilizer mixer machine

The efficient operation of a complete set of bio-organic fertilizer equipment is key to producing high-quality organic fertilizer. The fertilizer mixer machine, as the core equipment connecting raw material pretreatment and subsequent processing, directly determines the efficiency of the entire system and the quality of the product. It is an indispensable basic guarantee in all stages of production.

In the raw material pretreatment stage, the fertilizer mixer machine undertakes the core mixing task. Bio-organic fertilizer raw materials have complex components, requiring the precise mixing of fermented materials, beneficial microbial agents, and conditioning additives. The mixer machine ensures thorough contact between various raw materials through stable mixing, guaranteeing the even dispersion of microbial agents and laying the foundation for subsequent complete fermentation.

Improving the adaptability of the fertilizer mixer machine can further optimize the overall system efficiency. A high-quality mixer can flexibly adjust the rotation speed and duration according to the moisture content and particle size of the raw materials, preventing material clumping or excessive pulverization, and producing uniformly conditioned materials. This directly improves the operating efficiency of subsequent granulation and drying equipment.

Therefore, the fertilizer mixer machine is not an isolated link in the bio-organic fertilizer equipment system, but a fundamental core component that ensures continuous production and improves product quality. Paying attention to its selection and operational control is essential for the complete set of equipment to fully utilize its potential and consistently produce high-quality bio-organic fertilizer.

Drying and cooling: The core of quality assurance in fertilizer granule post-processing

Fertilizer granules after granulation often suffer from problems such as high moisture content, high temperature, and low strength, making them unsuitable for direct storage and transportation. In the post-processing stage of organic fertilizer production lines, the coordinated operation of dryers and coolers is crucial to solving these problems. They form a complete chain of “dehydration and shaping – cooling and strengthening,” directly determining the final quality of the fertilizer granules.

The drum fertilizer dryer undertakes the core task of “dehydration and shaping.” Granules fresh from the fertilizer granulator usually have a moisture content of 20%-30%, and need to be sent to the dryer to complete the drying process through a hot air circulation system: high-temperature hot air (60-80℃, adapted to the characteristics of organic fertilizer) fully contacts the granules, and with the help of internal baffles, ensures that each granule is evenly dehydrated, ultimately controlling the moisture content within the safe range of 12%-14%.

The drum fertilizer cooler connects the critical “cooling and strengthening” stage. The temperature of the dried granules can reach 60-80℃. If directly piled up, they are prone to re-moisturizing and clumping, and may even break due to thermal expansion and contraction. The cooler uses the principle of cold air heat exchange to quickly cool the high-temperature granules to near ambient temperature (temperature difference ≤5℃), and at the same time further tightens the granule structure during the cooling process, significantly improving the strength and hardness of the granules.

The core advantage of their combined operation lies in “process+quality complementarity.” During operation, it is necessary to match the capacities of the two machines, adjust the drying temperature and cooling air speed according to the granule size and raw material characteristics, and regularly clean the accumulated material inside the equipment to ensure smooth ventilation. As the “golden partners” in the post-processing of organic fertilizer production lines, their coordinated operation can increase the qualified rate of fertilizer granules to over 95%.

Core Cooling Equipment for Multiple Industries: Rotary Drum Cooler

In numerous industrial sectors such as cement calcination, chemical synthesis, metallurgical smelting, and building materials processing, cooling high-temperature materials is a crucial step in ensuring smooth subsequent production processes. The rotary drum cooler (also known as a gyratory cooler), as a core piece of equipment specifically designed for cooling high-temperature materials, has become an indispensable cooling tool in industrial production due to its efficient heat exchange capacity, stable operating performance, and wide adaptability. Through scientific heat exchange principles, it precisely cools high-temperature materials to a suitable temperature for storage, transportation, or further processing, providing solid support for enterprises to improve production efficiency and ensure product quality.

The stable and efficient operation of the rotary drum cooler stems from its scientifically designed structure, with each core component working in tandem to form a complete cooling system. The drum itself, the core of the equipment, houses a cooling device and lifting plates. This design is key to improving cooling efficiency—the lifting plates repeatedly lift and drop the material as the drum rotates, significantly increasing the contact area between the material and the cooling medium. The transmission device, composed of a motor, reducer, gears, and rollers, provides stable rotational power to the drum, ensuring uniform drum operation. The inlet and outlet respectively handle the entry of high-temperature materials and the discharge of cooled materials, ensuring smooth material flow. The cooling medium supply system provides air, water, or refrigerant, providing the necessary conditions for heat exchange. The support device uses a combination of rollers and support wheels to firmly support the drum, reducing frictional losses during rotation and ensuring stable operation. The sealing device effectively prevents leakage of cooling medium and materials, avoiding resource waste and improving cooling efficiency. Furthermore, the control system ensures a stable and efficient cooling process through precise control of parameters such as temperature and speed.

The working principle of the drum cooler is based on efficient heat exchange, with a clear process and rigorous logic. When high-temperature materials enter the drum through the inlet, the transmission device drives the drum to rotate slowly. During rotation, the lifting plates inside the drum continuously lift the material to a certain height before scattering it, creating a uniform curtain of material in a tumbling state. Simultaneously, the cooling medium supply system continuously inputs cooling medium into the drum, allowing the material and cooling medium to come into full contact and undergo direct heat exchange—the heat of the material is rapidly carried away by the cooling medium, thus lowering the temperature. The cooled material is discharged from the outlet under the driving force of the rotating drum; the cooling medium (such as hot air) that has absorbed heat is discharged through the exhaust port. The entire process is continuous and efficient, meeting the cooling needs of large-scale high-temperature materials.

The unique structure and working principle of the drum cooler give it many significant advantages, making it adaptable to the complex needs of multiple industries. High cooling efficiency is its core competitiveness. Through direct heat exchange and the assistance of the lifting plates, the material is cooled evenly and quickly, while also having a large throughput, easily handling the cooling of large batches of high-temperature materials. It is highly adaptable, capable of handling various materials of different sizes and shapes, whether it be cement clinker, metallurgical slag, or chemical synthetic materials, achieving stable cooling. The equipment has a relatively simple structure, a reasonable layout of core components, is easy to operate, and has low maintenance costs, significantly reducing the operational and maintenance burden on enterprises. Compared with other cooling methods, the drum cooler consumes less energy, especially when processing large batches of materials, where the energy-saving effect is more significant. Furthermore, the equipment is highly flexible in operation; by adjusting parameters such as drum speed and cooling medium flow rate, the degree of cooling can be precisely controlled to adapt to the cooling needs of different materials. More importantly, the discharged heat medium has the potential for recycling and can be used to preheat other materials or for drying operations, further improving energy efficiency and aligning with the concept of green production.

From clinker cooling in the cement industry to slag cooling in the metallurgical industry, from synthetic material cooling in the chemical industry to finished product cooling in the building materials industry, the drum cooler, with its core advantages of high efficiency, stability, and energy saving, provides strong support for the smooth operation of production processes in various industries. Against the backdrop of industrial production transforming towards higher efficiency and greener practices, this multi-industry-compatible cooling core equipment not only improves enterprise production efficiency but also helps enterprises achieve energy conservation and emission reduction goals, becoming one of the important pieces of equipment driving high-quality industrial development.

Integrating Cooling into Modern Fertilizer Manufacturing

The rotary drum cooler exemplifies the importance of specialized thermal management in continuous industrial processes. Its role is equally critical within the fertilizer industry, where precise temperature control is essential for producing high-quality, stable products.

Specifically, in a complete npk fertilizer production line, the cooler is a vital piece of professional fertilizer manufacturing equipment. It is typically positioned after the granulation and drying stages within the npk fertilizer production process. For example, following disc granulation production line shaping by a disc granulator for shaping or compaction in a roller press granulator production line, the hot granules must be rapidly cooled to set their structure and prevent caking. This cooling stage works in synergy with upstream equipment like the npk blending machine and the fertilizer granulator. Similarly, in an organic fertilizer production line that begins with a windrow composting machine, a cooler ensures the stability of the final granulated product from a bio organic fertilizer production line. Thus, the drum cooler is an indispensable link that bridges high-temperature processing with final product packaging and storage.

Ultimately, by ensuring granules are cooled efficiently and uniformly, this equipment protects product quality and enables the reliable, large-scale output that defines modern fertilizer manufacturing.

Malaysian Oil Palm Biomass: Oil Palm Empty Fruit Bunch (OPEFB)

A highly promising sustainable biofuel feedstock and fertilizer resource in the context of global energy challenges

Over the past few decades, global energy demand has increased dramatically, while traditional fossil fuels such as coal, oil, and natural gas have become increasingly scarce. Furthermore, the burning of these fossil fuels is a major driver of climate change, making it imperative to conserve existing energy resources and explore sustainable alternatives. Converting renewable energy materials into biofuels has emerged as a viable solution, offering a pathway to address pressing issues such as solid waste management, environmental pollution, the greenhouse effect, and energy shortages. Notably, oil palm biomass, a byproduct of the oil palm industry, is not only a highly promising biofuel feedstock but also has widespread and important applications in the fertilizer industry. Among these, oil palm empty fruit bunches (OPEFB), with their unique physicochemical properties, have become a high-quality resource in the fertilizer sector.

Malaysia is the world’s second-largest producer and exporter of palm oil, playing a crucial role in the global palm oil industry. In 2016, its production accounted for over 30% of the global total, and its exports accounted for 37% of global exports. This thriving industry generates a large amount of oil palm biomass annually—over 80 million tons of dry weight—a figure projected to increase by at least 40% by 2020. With the expansion of oil palm plantations, annual production is expected to increase by as much as 50 million tons by 2030. The main byproducts include palm kernel shells (PKS), oil palm empty fruit bunches (OPEFB), oil palm fronds (OPF), oil palm mesocarp fiber (OPMF), and palm oil mill effluent (POME). In 2017 alone, Malaysia generated 51.19 million tons of oil palm biomass residue from replanting, pruning, and processing activities, while the total amount of fresh fruit bunches processed during the same period was 101.02 million tons.

Unfortunately, due to the lack of effective utilization technologies, most of this biomass is discarded or burned, exacerbating waste problems, wasting cellulose-rich resources, and causing serious environmental problems such as air pollution. In fact, the value of oil palm biomass in the fertilizer industry is severely underestimated. Oil palm biomass is inherently rich in various essential plant nutrients such as nitrogen, phosphorus, potassium, calcium, and magnesium, and contains abundant organic matter, making it an ideal raw material for producing organic fertilizers. Oil palm empty fruit bunches (EFBs) are particularly noteworthy, as they have the lowest lignin content among all types of oil palm biomass (only about 14%), making them easier to decompose and mature, and allowing for faster release of nutrients into the soil.

In practical applications, oil palm biomass and EFBs can be converted into fertilizer through various methods. The most common is composting, where EFBs are mixed with manure, palm oil mill effluent, etc., and fermented to produce high-quality organic fertilizer. This process activates the nutrients and kills harmful bacteria and insect eggs. When applied to farmland, this organic fertilizer significantly increases soil organic matter content, improves soil structure, enhances soil water and nutrient retention capacity, and promotes the activity of soil microbial communities, reducing soil compaction and erosion. Furthermore, EFBs can be converted into biochar fertilizer through pyrolysis technology. Biochar has a porous structure that not only improves soil fertility but also adsorbs heavy metals and harmful substances from the soil, proving particularly effective in improving acidic and peat soils. Additionally, components such as potassium carbonate can be extracted from oil palm biomass ash for the preparation of liquid fertilizers, enabling the precise recovery and utilization of nutrients.

Beyond its value in the fertilizer sector, oil palm residue and other lignocellulosic biomass are among the most abundant renewable green carbon sources on Earth, with the potential to become substitutes for petroleum-based products. Their carbohydrate composition makes them suitable raw materials for renewable energy production, capable of producing biofuels such as bioethanol, biobutanol, and biomethane, as well as various value-added products. Currently, second-generation bioethanol extracted from lignocellulosic biomass is the most advanced of these products. Lignocellulosic biomass is mainly composed of lignin, cellulose, and hemicellulose. While cellulose and hemicellulose can be converted into ethanol, the high lignin content in oil palm biomass poses a significant challenge due to its complex and difficult-to-decompose structure. Therefore, pretreatment (delignification) is crucial before enzymatic hydrolysis, fermentation, and distillation to reduce the recalcitrance of the biomass. Effective pretreatment can alter the chemical composition, macrostructure, and microstructure of biomass, reducing cellulose crystallinity and increasing porosity. Ideal pretreatment techniques should be inexpensive, easy to operate, and yield high product recovery.

Notably, the lignin content of different types of oil palm biomass varies significantly (14% to 36%), with oil palm fruit residue having the highest lignin content and oil palm empty fruit bunches having the lowest. This characteristic not only facilitates its efficient utilization in the fertilizer industry but also guides the selection of appropriate pretreatment methods for biofuel conversion. With the growing global demand for alternatives to fossil fuels, food security concerns prioritizing non-edible biofuel sources, and the increasing demand for green organic fertilizers in agriculture, oil palm biomass has attracted widespread research attention. Its dual value in both the biofuel and fertilizer sectors makes it an important resource for promoting sustainable energy development and ecological agriculture, with broad application prospects.

Conclusion: A Sustainable Cycle from Waste to Resource

The Oil palm empty fruit bunch (OPEFB) exemplifies a perfect model of circular economy, transitioning from a major agricultural waste to a valuable resource. The primary uses of oil palm empty fruit bunch are realized through its integration into sustainable agricultural systems, most notably as a primary feedstock for organic fertilizer production.

To leverage OPEFB effectively, it is processed through a complete organic fertilizer manufacturing system. The journey begins with controlled organic fertilizer fermentation, optimized by advanced fermentation composting turning technology to accelerate decomposition and enhance quality. The resulting mature compost can then be processed through a bio organic fertilizer production line. For final product formation, the material undergoes organic fertilizer production granulation. Producers can choose specialized equipment like an organic fertilizer disc granulation production line or opt for a more versatile organic fertilizer combined granulation production line to shape the compost into uniform, market-ready fertilizer granules. This systematic approach transforms OPEFB waste into a high-value soil amendment, closing the nutrient loop sustainably.

Thus, by combining innovative biological treatment with modern mechanical processing, OPEFB is successfully converted from an environmental burden into a cornerstone of sustainable agriculture and green industry.