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Henan Hongke Heavy Machinery Co., Ltd. is pleased to report that our Φ3.5×75m rotary kiln production line — designed for 400 tons per day of high-reactivity active lime — has entered the site construction phase in Ningxia, China. This project underscores our engineering capability in delivering large-scale, thermally efficient lime calcination systems for demanding industrial applications.
Project Context: Strategic Lime Production in Northwestern China
The Ningxia Hui Autonomous Region, a prominent industrial corridor in northwestern China, hosts significant steelmaking, calcium carbide, and coal chemical operations — all of which depend on a consistent supply of high-quality active lime (CaO) for fluxing, chemical synthesis, and environmental abatement.
Our client, a major regional industrial operator, identified a critical supply gap: existing lime production assets could not meet the reactivity, purity, or volume specifications required by downstream users. They commissioned Henan Hongke Machinery to engineer a complete rotary kiln-based calcination line with the following performance targets:
| Parameter | Target |
|---|---|
| Daily capacity | 400 metric tons of active lime |
| Product reactivity (ASTM C110) | ≥ 340 ml (4N HCl method) |
| Residual CO₂ in product | ≤ 2.0% |
| Fuel types | Pulverized coal or natural gas (dual-fuel capable) |
| Stack particulate emission | ≤ 30 mg/Nm³ |
| Annual uptime | ≥ 92% (scheduled maintenance excluded) |
System Engineering: Φ3.5×75m Rotary Kiln Line
The centerpiece of this production line is a Φ3.5m diameter × 75m length rotary kiln — a well-established configuration in the lime industry for medium-to-large capacity applications. Henan Hongke Machinery performed full process engineering, including mass and heat balance calculations, refractory selection, and mechanical design, to ensure optimal performance across the operating envelope.
Rotary Kiln – Technical Specifications
| Parameter | Specification |
|---|---|
| Shell inner diameter | 3.5 m |
| Shell length (overall) | 75 m |
| L/D ratio | ~21.4 : 1 |
| Kiln slope | 3.5–4.0% (adjustable) |
| Rotational speed | 0.5–3.5 rpm (variable-frequency drive) |
| Burning zone temperature | 1,200–1,250°C (controlled) |
| Shell material | Q345R (pressure vessel grade) |
| Refractory system | 230 mm high-alumina (Al₂O₃ ≥ 70%) working lining + 80 mm insulation layer |
| Drive configuration | Dual-drive (main + auxiliary) with torque-limiting coupling |
| Girth gear | Split-type, cast steel (ZG310-570), precision machined |
Complete System Architecture
Henan Hongke Machinery supplied a fully integrated production train — not merely the kiln itself. The scope includes:
1. Vertical Preheater (PFR-type)The preheater recovers thermal energy from kiln exhaust gases (typically 900–1,050°C at the inlet) to preheat limestone feed from ambient to approximately 900°C. This achieves 25–35% pre-calcination of the feed material before it enters the kiln, reducing the specific fuel consumption by up to 40% compared to non-preheater configurations.
2. Φ3.5×75m Rotary KilnThe primary calcination vessel, where limestone (CaCO₃) undergoes endothermic decomposition to quicklime (CaO) and CO₂. The 75m length provides a residence time of approximately 2.5–3.5 hours, ensuring complete conversion with minimal dead-burned or under-burned product.
3. Vertical Cooler (sleeve-type)The cooler reduces product temperature from ~1,100°C to <100°C in a counter-current air flow arrangement, quenching the lime to preserve its microporous structure and high reactivity. Preheated secondary combustion air (350–400°C) recovered from the cooler is recirculated to the kiln, improving overall thermal efficiency.
4. Multi-channel BurnerThe burner provides adjustable flame shaping and temperature profiling. It is designed for dual-fuel operation with automated fuel switching between pulverized coal and natural gas, allowing the client to optimize fuel costs based on market availability.
5. Dedusting SystemA two-stage particulate control train — primary cyclone separator followed by a pulse-jet bag filter — achieves outlet dust concentrations consistently below 30 mg/Nm³, complying with GB 4915-2013 emission standards.
6. DCS-based Process ControlThe line operates under a distributed control system (DCS) with continuous monitoring of:
Kiln shell temperature (pyrometer scans, 8 zones)
Burning zone temperature and flame profile
Preheater and cooler temperature gradients
Gas flow, draft pressure, and O₂/CO concentration
Feed rate and product discharge rate
All process data is logged for performance analysis and optimization.
Construction Status: Site Assembly Underway
As of the current reporting period, the Ningxia project has advanced to the on-site construction and assembly phase. Milestones achieved include:
Fabrication complete — All major components manufactured at Henan Hongke's 50,000m² production facility, with full NDT inspection (UT/MT) and dimensional verification.
Site civil works — Foundations, anchor bolt settings, and utility connections substantially complete.
Mechanical installation — Kiln support rollers, thrust roller assembly, and base frames positioned; shell alignment and circumferential welding in progress.
Engineering supervision — Henan Hongke has deployed a field installation team including mechanical, refractory, and electrical specialists to supervise assembly, alignment, and pre-commissioning checks.
Performance Projections and Client Value
Once commissioned and stabilized, the Ningxia lime kiln line is expected to deliver the following quantified benefits:
| Performance Metric | Projected Value |
|---|---|
| Specific heat consumption | ≤ 1,100 kcal/kg of active lime (with preheater) |
| Specific fuel consumption | ≤ 155 kg coal equivalent / ton lime |
| Product reactivity (activity) | ≥ 340 ml (meeting YB/T 042-2014 standard) |
| CaO content (available) | ≥ 90% |
| Ignition loss (LOI) | ≤ 2.5% |
| Annual CO₂ reduction (vs. non-preheater) | ~6,500 metric tons (estimated) |
For the client, this translates to:
Lower operating costs — energy recovery systems reduce fuel consumption and associated costs
Premium product positioning — high-reactivity lime commands price premiums in steelmaking and chemical markets
Regulatory security — dust emissions well below statutory limits
Supply chain stability — in-region production eliminates long-haul logistics and price volatility
About Henan Hongke Heavy Machinery Co., Ltd.
Henan Hongke Heavy Machinery Co., Ltd. (Henan Hongke Machinery) is a vertically integrated engineering and manufacturing company specializing in thermal processing equipment. Established in 2006, our core product range includes:
Rotary Kilns — lime, cement, metallurgical, and mineral calcination applications
Rotary Dryers — sludge, biomass, ore, and chemical drying
Ball Mills — wet and dry grinding for minerals, cement, and ceramics
Crushers — jaw, impact, cone, and hammer crusher designs
Our engineering capabilities span process design, mechanical detail engineering, manufacturing, site installation supervision, and commissioning. We hold ISO 9001 certification and serve clients across China, Southeast Asia, South Asia, the Middle East, and Africa.
Path to Commissioning
Following the current site construction phase, the project will proceed through:
| Phase | Activities |
|---|---|
| Mechanical completion | All equipment installed and aligned; torque checks completed |
| Refractory installation | Kiln lining, preheater brickwork, and burner block installation |
| System integration | Ducting, piping, electrical, and control system interconnect |
| Cold commissioning | No-load testing of drives, conveyors, fans, and control logic |
| Hot commissioning | Lining dry-out, burner light-off, and initial limestone feed |
| Performance testing | 72-hour continuous run at full capacity; verification of all KPIs |
Henan Hongke will maintain an on-site presence through to final acceptance, ensuring the system achieves or exceeds all design specifications.
Engineering Inquiry
For lime, cement, or mineral calcination projects requiring a custom-engineered rotary kiln system — sized and specced to your feed material, fuel availability, and production targets — please direct inquiries to Henan Hongke Heavy Machinery Co., Ltd.
We provide engineered solutions, not commoditized equipment.
Henan Hongke Heavy Machinery Co., Ltd.
Rotary Kilns | Dryers | Ball Mills | Crushers – Precision Engineering for Thermal Processing
