Client Location: De'an County, Jiujiang City, Jiangxi Province, China
Project Type: Active Lime Rotary Kiln Production Line
Annual Production Capacity: 8,000 tons/year
Equipment Supplier: Henan Hongke Heavy Machinery Co., Ltd.
Commissioned: 2025
Henan Hongke Heavy Machinery Co., Ltd. (hereinafter "Henan Hongke Machinery") successfully designed, manufactured, and commissioned a complete active lime rotary kiln production line in De'an County, Jiujiang City, Jiangxi Province, China . This turnkey project delivers an annual output of 8,000 tons of high-quality active lime, meeting the client's stringent requirements for product purity, energy efficiency, and environmental compliance .
De'an County is situated in northern Jiangxi Province, a region with abundant limestone reserves and a growing demand for construction-grade and metallurgical lime . The area's well-developed industrial infrastructure and convenient transportation networks make it an ideal location for lime manufacturing operations. This project exemplifies Henan Hongke Machinery's capability to deliver customized, cost-effective lime production solutions in diverse geographic settings across China and worldwide .
Production Line Configuration and Equipment
The De'an County lime rotary kiln production line adopts the proven vertical preheater + rotary kiln + vertical cooler system architecture, which is widely recognized as the most energy-efficient and environmentally responsible configuration for active lime production . Below is a detailed breakdown of each major equipment component.
1. Raw Material Handling and Feeding System
Limestone blocks in the size range of 20–50 mm are first delivered to the plant site and stored in a covered raw material yard . The material undergoes screening to remove fines and oversized particles, ensuring only properly sized limestone enters the production process . A vibrating feeder and bucket elevator transport the qualified limestone to the top feed bin of the vertical preheater .
The feed bin is equipped with upper and lower level indicators to maintain consistent material flow and prevent overfeeding or underfeeding . The automated control system ensures uniform distribution of limestone across all preheating chambers, optimizing thermal exchange efficiency .
2. Vertical Preheater
The vertical preheater is a critical component that dramatically improves system thermal efficiency by utilizing waste heat from the rotary kiln exhaust gases . In this configuration, hot flue gases at approximately 1,000–1,150°C from the kiln tail enter the preheater and pass upward through the descending limestone bed in the annular channel .
Through this counter-current heat exchange process, the limestone is preheated to approximately 900°C, achieving a pre-decomposition rate of 20–30% before entering the rotary kiln . This preheating stage significantly reduces the residence time required in the rotary kiln and lowers overall fuel consumption by up to 40% compared to systems without preheaters .
The preheater features multiple hydraulic push rod assemblies that sequentially discharge preheated material into the rotary kiln at precisely controlled intervals . Each push rod operates independently via dedicated hydraulic cylinders, and the push interval timing can be adjusted through the PLC control system to optimize feed rate and product quality .
The preheater body is constructed with refractory-lined steel shells, and all critical high-temperature components are manufactured from heat-resistant alloy steel, ensuring reliable operation at temperatures exceeding 1,000°C .
3. Rotary Kiln
The heart of the production line is the rotary kiln — a slightly inclined, slowly rotating cylindrical furnace . The kiln shell is fabricated from high-quality carbon steel plate with precision-welded seams and internally lined with refractory bricks for thermal insulation and structural protection .
Key technical specifications of the rotary kiln include:
The kiln operates on the principle of combined rotational and gravitational movement. As the cylinder rotates, limestone particles tumble circumferentially while simultaneously advancing axially from the high end (kiln tail) toward the low end (kiln head) . This dual-motion ensures thorough and uniform heating of all material particles.
The calcination process inside the rotary kiln completes the thermal decomposition of calcium carbonate (CaCO₃) into calcium oxide (CaO) and carbon dioxide (CO₂) at temperatures between 1,100°C and 1,350°C . The entire decomposition reaction is carefully controlled through variable-frequency motor drive, which allows operators to adjust kiln rotation speed in real time based on preheater decomposition rates and product quality requirements .
The combustion system employs a multi-channel burner capable of firing coal powder, natural gas, or mixed fuels . The burner design enables independent adjustment of each air channel's exit velocity, allowing operators to create the optimal flame shape for different operating conditions .
4. Vertical Cooler
Immediately downstream of the rotary kiln, the vertical cooler rapidly quenches the hot lime product (typically 1,000–1,200°C at kiln discharge) to below 100°C . This rapid cooling is essential for preserving the high reactivity (activity degree) of the lime product, as slow cooling can cause crystal growth and reduce the lime's hydration performance .
The vertical cooler operates without moving parts, relying instead on gravity flow and forced air cooling . Cold air is blown upward through the descending lime bed, achieving efficient heat exchange. The resulting hot air (approximately 600°C) is recovered and recycled back to the rotary kiln as secondary combustion air, further improving overall system thermal efficiency .
The cooled lime exits the cooler at a temperature approximately 40°C above ambient, making it safe for immediate handling, conveying, and storage .
5. Exhaust Gas Treatment System
Environmental compliance is a core design principle of the De'an County production line . The exhaust gas treatment system incorporates a multi-stage purification process:
- Multi-tube cooler: Reduces the kiln tail exhaust temperature from approximately 280°C to below 200°C .
- Pulse jet bag filter: Captures fine particulate matter using PTFE membrane-coated filter bags, achieving dust removal efficiency exceeding 99.9% .
- High-temperature induced draft fan: Maintains proper system negative pressure and drives exhaust through the treatment train .
The treated exhaust gas meets China's stringent emission standards, with outlet dust concentration consistently maintained below 30–50 mg/Nm³ . This ensures full compliance with national and local environmental regulations, a critical requirement for lime production facilities in Jiangxi Province and throughout China .
6. Finished Product Conveying and Storage System
Cooled lime exits the vertical cooler and is conveyed through a chain plate conveyor, bucket elevator, and belt conveyor system to the finished product screening station . A vibrating screen separates the lime into two fractions:
- Qualified product (>5 mm): Conveyed to the active lime storage silo for dispatch.
- Fine powder (<5 mm): Collected in a separate fines silo for alternative applications.
Both silos are equipped with electric discharge valves for controlled loading and dispatch .
7. Automation and Control System
The entire production line is managed by a DCS (Distributed Control System) integrated with PLC controllers, providing centralized monitoring and control from a single control room . The system monitors and regulates key parameters in real time, including:
- Kiln temperature and pressure profiles
- Preheater material levels and push rod timing
- Cooler discharge temperature
- Exhaust gas composition and flow rates
- Fuel and air supply ratios
The intelligent control system includes built-in expert algorithms that automatically adjust combustion air volume, feed rate, and kiln rotation speed based on raw material characteristics and production targets . This minimizes operator intervention, reduces human error, and ensures consistent product quality throughout each production cycle .
Technical Advantages of the De'an County Production Line
The Henan Hongke Machinery lime rotary kiln production line offers several significant advantages that directly benefit the client's operations and bottom line:
High Product Quality and Consistency
The rotary kiln's open calcination design allows sulfur-containing flue gases to exit the system promptly, preventing sulfur contamination of the lime product . The uniform tumbling motion ensures all limestone particles receive consistent heat treatment, resulting in a product with low over-burning and under-burning rates (typically <8%) and high activity degrees of 340–400 ml . This quality level meets the demanding requirements of steelmaking, metallurgy, and chemical processing industries.
Superior Raw Material Utilization
Unlike vertical shaft kilns that require carefully graded feedstock, the rotary kiln system can directly process limestone particles in the 10–50 mm size range . This capability allows the client to utilize finer limestone fractions (10–30 mm) that would otherwise be waste material in conventional kiln operations, significantly improving overall quarry yield and resource utilization .
Excellent Energy Efficiency
The combination of vertical preheater and vertical cooler creates a highly efficient thermal cycle . The preheater recovers waste heat from kiln exhaust to pre-decompose 20–30% of the limestone before it enters the kiln, while the cooler recovers sensible heat from the hot lime product to preheat combustion air . Together, these systems reduce specific heat consumption to approximately 5,000–5,225 kJ/kg CaO, well below industry averages for conventional lime kilns .
Environmental Compliance
The multi-stage exhaust gas treatment system ensures all emissions meet or exceed China's environmental protection standards . The fully enclosed process design minimizes fugitive dust emissions, while the advanced bag filtration system achieves outlet dust concentrations below 30 mg/Nm³ . These features are particularly important given the increasingly stringent environmental regulations governing lime production in Jiangxi Province .
High Automation and Low Labor Requirements
The DCS-based automation system enables centralized control of the entire production process with minimal operator involvement . This reduces labor costs, improves operational safety, and enables rapid response to changing production conditions or quality requirements .
Compact Footprint and Short Construction Period
The optimized system design, featuring the vertical preheater to shorten required kiln length, reduces the overall plant footprint . Henan Hongke Machinery's standardized engineering approach and modular equipment design enable fast construction and commissioning, with typical project timelines of 6–7 months from design to full production .
Project Delivery and Commissioning by Henan Hongke Machinery
Henan Hongke Heavy Machinery Co., Ltd. managed every phase of this project, from initial feasibility assessment through final production handover . The comprehensive service package included:
- 1.Engineering Design: Customized process flow design and plant layout optimized for the client's specific site conditions in De'an County .
- 2.Equipment Manufacturing: All major and auxiliary equipment manufactured at Henan Hongke Machinery's production facilities under strict quality control protocols .
- 3.Transportation and Logistics: Coordinated shipping of all equipment to the project site in Jiangxi Province.
- 4.Installation Supervision: Henan Hongke Machinery dispatched experienced engineers to the site to supervise equipment installation and ensure proper alignment and assembly .
- 5.Commissioning and Start-up: Full system testing, parameter optimization, and trial production to verify performance meets design specifications .
- 6.Operator Training: Comprehensive training for the client's operations team, covering normal operation, routine maintenance, troubleshooting, and safety procedures .
All equipment undergoes a 24-hour factory test run prior to shipment, with detailed inspection reports provided alongside the delivery .
Jiangxi Province: A Growing Market for Active Lime
The De'an County project reflects the broader industrial development trend in Jiangxi Province. The region has witnessed significant investment in limestone processing and calcium-based chemical industries in recent years . De'an County, in particular, has emerged as a hub for lime and calcium oxide production, with multiple projects demonstrating the area's strong limestone resource base and supportive industrial policy environment .
The successful commissioning of this 8,000 tons/year production line further strengthens Henan Hongke Machinery's presence in the Jiangxi market and demonstrates the company's ability to serve clients of all scales — from small and medium-sized operations to large industrial complexes .
About Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd. is a professional rotary kiln manufacturer and complete lime production line supplier based in Henan Province, China . The company specializes in the design, manufacture, and installation of active lime rotary kiln production lines with capacities ranging from 150 tons/day to over 1,500 tons/day .
With years of experience in the lime industry, Henan Hongke Machinery has delivered successful projects across China and in international markets including Southeast Asia, Africa, Central Asia, and the Middle East . The company's product portfolio includes:
- Active lime rotary kiln production lines
- Vertical preheaters and vertical coolers
- Coal powder preparation systems
- Exhaust gas treatment systems
- DCS automation control systems
- Complete turnkey project services
Henan Hongke Machinery is committed to delivering reliable, energy-efficient, and environmentally compliant lime production solutions that create lasting value for clients worldwide .
Contact Us
Interested in a lime rotary kiln production line for your project? Henan Hongke Heavy Machinery Co., Ltd. offers free consultation, customized process design, and competitive pricing for lime production systems of all scales.
Get in touch today to discuss your requirements and receive a detailed project proposal tailored to your specific needs.