What is a Pomace Dryer?

A pomace dryer is an industrial machine specifically designed to reduce the moisture content of fruit, vegetable, or other organic processing residues (pomace) using thermal energy and mechanical handling.

Think of it as a system engineered to handle the specific challenges of pomace. Unlike drying simple materials like sand, pomace requires careful consideration of several factors.

Core Function

The main goal is evaporation. Heat is applied to turn the water within the pomace into vapor, which is then carried away, usually by a stream of air. However, the way heat is applied and how the pomace is moved through the dryer is critical.

Key Considerations for Pomace

• High Initial Moisture: Pomace (from apples, grapes, olives, citrus, vegetables, etc.) is often very wet, sometimes over 80% moisture.
• Fibrous Nature: The material is often stringy and doesn’t flow easily, requiring robust handling systems.
• Stickiness/Sugar Content: Many pomaces, especially from fruits, are high in sugars, which can cause stickiness and burning issues during drying.
• Heat Sensitivity: Nutritional components (for feed) or valuable compounds (for extraction) can be damaged by excessive heat.

ZONEDING designs pomace dryers considering these factors to ensure efficient and effective moisture removal while preserving product quality.

Application of pomace dryer

The fruit residues dryer is widely used for drying apple pomace, pineapple residues, citrus pomace, tangerine peel and other fruit pomace. It can also be used to dry distiller’s grains, bagasse, cassava residues, olive pomace, bean dregs, etc.

Why Should You Dry Pomace and What Can Do With It?

Drying pomace dramatically reduces its volume and weight, stops spoilage, and transforms it into valuable products like animal feed, biofuel, fertilizer, or extraction feedstock.

Reasons to Dry Pomace

1. Volume & Weight Reduction: Drying can reduce pomace volume and weight by 70-80% or more. This drastically cuts down on transportation and disposal costs.
2. Stabilization & Preservation: Wet pomace decays rapidly. Drying removes the water that microbes need to grow, making the pomace stable for long-term storage and transport without spoilage or odor issues.
3. Value Creation: Instead of paying to dispose of waste, you create a potentially marketable product.

Value-Added Uses

• Animal Feed: Dried fruit and vegetable pomace can be a nutritious supplement for livestock, rich in fiber and sometimes residual sugars/proteins. Drying must preserve these nutrients.
• Biofuel: Dried pomace has significant energy content and can be burned directly or pelletized for use as a renewable fuel source. Maximizing dryness is key here.
• Fertilizer / Soil Amendment: Dried pomace adds organic matter back to the soil. Drying makes it easier to handle, store, and spread.
• Extraction Feedstock: Some pomaces contain valuable compounds like pectin (apples, citrus), polyphenols (grapes), or oils (olives). Drying is often the first step before extraction, requiring careful temperature control.

How Does a Pomace Dryer Work?

A pomace dryer works by continuously moving the wet material through a heated environment. Hot air or heated surfaces transfer energy to the pomace, evaporating water, which is then carried away by an airflow.

The core principle is heat and mass transfer, but the implementation varies depending on the dryer type and the pomace characteristics.

Key Operational Elements

1. Material Feeding: Wet pomace is fed into the dryer at a controlled rate. Consistent feeding is important for stable operation.
2. Heat Source: Energy is supplied, usually by burning fuel (natural gas, LPG, biomass), using steam, or utilizing waste heat. This heats air or a surface that contacts the pomace.
3. Heat Transfer: Heat moves from the hot air/surface into the wet pomace. This provides the energy needed for water to evaporate (turn into vapor). Common methods include:
   • Convection: Hot air flows directly through or over the pomace.
   • Conduction: Pomace contacts hot surfaces (like in a paddle dryer).
   • Radiation: Heat radiates from hot surfaces (less common as primary method).
4. Material Conveyance: The pomace is moved through the dryer (e.g., tumbling in a drum, carried on a belt, pushed by paddles) to expose new surfaces to the heat and ensure even drying.
5. Moisture Removal (Mass Transfer): An airflow (natural or forced by fans) passes through the dryer, picks up the evaporated water vapor, and carries it out of the system, usually to a dust collector or odor control unit .
6. Discharge: The dried pomace exits the dryer and is often cooled before storage.

ZONEDING selects and designs the specific combination of these elements best suited for your pomace type and drying goals.

Which Dryer Technology (Rotary, Belt, Paddle) Best Suits High-Moisture, Perishable, Sticky Pomace?

Belt dryers are often preferred for sticky, high-sugar pomace due to better temperature control. Rotary dryers need careful design for pomace, while paddle dryers excel at handling stickiness but are less common for pomace.

The unique properties of pomace significantly influence the choice of dryer technology. Here’s a breakdown:

Dryer Type Considerations for Pomace

Dryer Type	Suitability for Sticky/Sugary Pomace (Insight #2)	Temperature Control	Handling Fibrous Material	Common Use for Pomace
Rotary Dryer	Lower (Risk of sticking/burning without special design)	Moderate	Good (Tumbling action)	Common, needs care
Belt Dryer	Higher (Lower temps, zoned control possible)	Good to Excellent	Fair (Needs even feed)	Increasingly common
Paddle Dryer	Excellent (Self-cleaning paddles)	Excellent	Good (Mixing action)	Less common

Detailed Comparison

• Rotary Dryers:
  • Pros: Robust, high throughput, good mixing for fibrous material.
  • Cons: Direct high heat can easily burn sugary pomace. Stickiness can cause buildup on lifters without special designs. Requires careful temperature and airflow control.
• Belt Dryers:
  • Pros: Gentler drying at lower temperatures, ideal for heat-sensitive or sugary pomace. Zoned temperature control allows optimizing the drying profile. Good for achieving uniform drying if fed evenly.
  • Cons: Requires consistent, well-distributed feed. Less tolerant of large clumps than rotary dryers. Can have a larger footprint.
• Paddle Dryers (Indirect Heat):
  • Pros: Excellent for extremely sticky materials due to paddle action. Precise temperature control. Often more thermally efficient.
  • Cons: Higher initial cost. Less common specifically for pomace compared to sludge or chemicals, but potentially viable for very difficult cases.

ZONEDING helps analyze your specific pomace and recommends the most suitable and cost-effective dryer technology. Often, for high-sugar fruit pomace, a well-designed belt dryer offers the best balance of control and efficiency.

What are the Advantages of Using a Pomace Dryer?

Using a pomace dryer significantly reduces disposal costs, creates valuable byproducts, improves storage and handling, and helps meet environmental regulations by minimizing waste.

Key Benefits

• Reduced Disposal Costs: This is often the primary driver. Wet pomace is heavy and bulky, leading to high landfill or disposal fees. Drying dramatically cuts down on this weight and volume, saving significant money.
• Value Creation / Revenue Stream: Transforms a waste liability into an asset. Selling dried pomace as animal feed, biofuel, or other products can generate income, offsetting operational costs and potentially creating profit.
• Improved Storage & Handling: Wet pomace spoils quickly, creates odors, and is difficult to handle. Dried pomace is stable, can be stored for long periods, flows better, and is easier to transport and integrate into other processes.
• Environmental Compliance: Reduces the amount of organic waste sent to landfills, helping meet environmental regulations and promoting sustainability. Capturing and treating dryer emissions (odor/dust) further improves environmental performance.
• Process Efficiency: For businesses extracting compounds from pomace, drying is often a necessary preparatory step, enabling efficient extraction processes.

By implementing a ZONEDING pomace drying solution, you can turn a problematic waste stream into a manageable and potentially profitable part of your operation.

What Problems Are Commonly Encountered During Pomace Drying?

Common pomace drying problems include material sticking and fouling dryer surfaces, uneven drying leading to wet/burnt spots, problematic odors, fire or dust explosion risks, and difficulties with material feeding and discharge.

Frequent Operational Issues

• Sticking and Fouling : High sugar or pectin content can make pomace very sticky at certain moisture levels, causing it to build up on dryer walls, belts, or lifters. This reduces heat transfer efficiency and can lead to blockages. Solution: Appropriate dryer type (e.g., belt, paddle), temperature control, potential use of anti-stick coatings or cleaning mechanisms.
• Uneven Drying : Non-uniform airflow or poor material distribution results in some pomace being too wet (risk of spoilage) while other parts are too dry or even burnt. Solution: Proper feed distribution, engineered airflow design, potentially turning/mixing mechanisms.
• Odor Emissions : Drying releases volatile organic compounds (VOCs), causing potentially strong odors. Solution: Integrating appropriate odor control systems (thermal oxidizer, biofilter, etc.) into the plant design.
• Fire and Explosion Risks : Organic dust is explosive. Sugary or oily residues can smolder or self-ignite. Solution: Rigorous cleaning, temperature monitoring, spark detection/suppression, explosion venting, proper cooling before storage.
• Material Handling Issues : Wet pomace can bridge in hoppers or stick to conveyors. Dry pomace can be dusty. Solution: Robust, well-designed feeders, conveyors, and discharge systems suitable for fibrous and potentially dusty materials.

ZONEDING’s experience helps anticipate these problems. We design systems with features to mitigate these risks and provide guidance on proper operation to minimize issues.

How Do You Properly Maintain a Pomace Dryer?

Proper pomace dryer maintenance involves regular cleaning to prevent buildup, inspecting and lubricating moving parts, checking airflow systems, and verifying safety device functionality.

Essential Maintenance Tasks

1. Cleaning: This is paramount for pomace dryers. Regularly remove any accumulated pomace buildup from internal surfaces, belts, lifters, seals, and discharge areas. Buildup reduces efficiency and significantly increases fire risk. Design for accessibility helps.
2. Mechanical Inspection: Regularly check belts (tension, condition), chains (tension, lubrication), bearings (noise, temperature, lubrication), gearboxes (oil level), seals (wear, leakage), and structural components for wear or damage.
3. Lubrication: Follow the manufacturer’s lubrication schedule for bearings, chains, drives, and other moving parts using the recommended lubricants.
4. Airflow System Checks: Inspect fans for vibration and damage. Ensure air ducts, plenums, and any filter screens are clear of obstructions to maintain uniform airflow. Check dust collection systems (cyclones, baghouses) are functioning correctly.
5. Heat Source Maintenance: Inspect burners, combustion chambers, or heat exchangers according to manufacturer guidelines.
6. Safety System Checks: Regularly test temperature sensors, interlocks, spark detection and suppression systems (if fitted), and emergency stops to ensure they are functional.
7. Control System Calibration: Periodically check the calibration of key sensors (temperature, moisture) for accurate process control.

What Equipment Makes Up a Complete Pomace Drying Line?

A complete pomace drying line typically includes material feeding equipment, potentially a dewatering press, the dryer unit, a heat source, air handling fans, a cooling system, dust collection, and a control system.

Understanding the full scope is crucial for planning and budgeting. Here are the common components:

Typical Production Line Equipment

1. Input Handling & Feeding :
   • Receiving Hopper: Where wet pomace is initially dumped.
   • Conveyor(s): Transport pomace to the next stage (e.g., belt, screw conveyor).
   • Feeder: Controls the rate pomace enters the system (e.g., variable speed screw feeder) for consistent operation.
2. Mechanical Dewatering Press (Optional but Recommended):
   • Screw Press or Belt Press: To mechanically remove a significant portion of water before thermal drying, saving energy.
3. Dryer Unit:
   • The core machine (e.g., Rotary, Belt, Paddle) where thermal drying occurs.
4. Heat Source:
   • Burner System (Gas, Oil, Biomass): Generates hot air directly or indirectly.
   • Steam Boiler / Thermal Oil Heater: Provides heat for indirect dryers or air heating coils.
5. Air Handling System:
   • Hot Air Fan(s): Move heated air into/through the dryer.
   • Exhaust Fan(s): Remove moist air from the dryer.
   • Ducting: Channels airflow.
6. Discharge & Cooling System :
   • Discharge Mechanism: Safely removes dried pomace (e.g., rotary valve).
   • Cooling Conveyor/Cooler: Reduces temperature before storage to prevent self-heating or degradation.
7. Dust Collection / Emission Control:
   • Cyclone(s): Removes coarse dust particles.
   • Baghouse / Wet Scrubber: Removes finer dust particles for environmental compliance and safety.
   • Odor Control System(If required): Thermal oxidizer, biofilter, etc.
8. Control System:
   • PLC (Programmable Logic Controller): Automates operation, monitors temperatures, speeds, moisture levels, and safety interlocks. Includes operator interface.

ZONEDING specializes in designing and supplying complete, integrated pomace drying lines, ensuring all components work seamlessly together for optimal performance and reliability.

Why Choose ZONEDING for Pomace Dryers?

Choose ZONEDING for our proven experience in robust dryer design, ability to customize solutions for challenging materials like pomace, focus on energy efficiency and safety, and capacity to deliver complete, integrated production lines.

While pomace differs from our traditional mining focus, our core engineering strengths in drying and handling difficult materials translate directly. Here’s what matters:

• Robust Design Experience: Our background in heavy industries means we build durable equipment designed for continuous operation, essential for handling fibrous or potentially abrasive pomace.
• Customization Expertise: We don’t offer one-size-fits-all solutions. We analyze your specific pomace characteristics (moisture, sugar, fiber) and tailor the dryer type, configuration, and materials accordingly.
• Focus on Process Efficiency: We understand the importance of energy savings. We emphasize optimizing mechanical dewatering and designing efficient airflow systems to minimize operating costs.
• Integrated Safety Approach: We incorporate safety features addressing pomace-specific risks like fire and dust explosions and can integrate necessary emission controls. Design for maintenance access is standard.
• Complete Line Solutions: We can design, manufacture, and supply the entire drying line – from feed handling to discharge, including critical components like dewatering, heat sources, and controls – ensuring seamless integration.
• Full-Service Support: We provide support throughout the project lifecycle, including design, manufacturing, installation supervision, commissioning, training, and after-sales service.
• Global Reach & Factory Direct: Our international experience and direct sales model allow us to offer competitive solutions worldwide.

Choosing ZONEDING means partnering with an experienced manufacturer committed to delivering a pomace drying solution that reliably meets your operational goals and turns your byproduct challenge into an opportunity.

Technical Parameters

Item/Unit/Model	Φ2.5×7m	Φ2.7×7m	Φ3.0×7.0m	Φ3.2×7.0m	Φ3.6×8m
Diameter of outer cylinder(m)	2.5	2.7	3.0	3.2	3.6
Length of outer cylinder(m)	7	7	7.0	7.0	8
Cylinder volume( m³ )	16.63	16.63	52.678	52.678	81.38
Rotating speed of cylinder(rpm)	4-10	4-10	4 -10	4 -10	4 -10
Initial moisture of slag(%)	10-12	10-12	10-12	10-12	10-12
Final moisture of slag(%)	1	1	1	1	1
Initial moisture of yellow ground(%)	8-10	8-10	8-10	8-10	8-10
Final moisture of yellow ground (%)	0.5-1	0.5-1	0.5-1	0.5-1	0.5-1
Highest intake air temperature(℃)	700-750℃	700-750℃	700-750℃	700-750℃	700-750℃
Production capacity(T/h)	Yellow sand:25-30 Slag: 20-25	Yellow sand:30-35 Slag:25-30	Yellow sand:35-40 Slag:30-35	Yellow sand:45-50 Slag:35-40	Yellow sand:65-70 Slag:60-65
Motor type	Y2-132m-4E	Y2-132m-4E	Y2-160m-4	Y2-160m-4	Y2-160m-4
Motor power(kw)	7.5×2	11×2	7.5×4	7.5×4	15×4
Reducer type	XWD7-23-11W	XWD7-23-11W	XWD6-23-7.5KW	XWD6-23-7.5KW	XWD8-23-15KW
Velocity ratio of reducer	29	29	29	29	29

Customer Cases