A Case Study in Efficient Waste Heat Recovery

 Xi'an Yurcent's Coal Mine Gas Comprehensive Utilization Project is equipped with two 7.2 t/h vertical L-type natural circulation medium-temperature medium-pressure waste heat boilers, designed explicitly for high-temperature waste gas heat recovery from RTO systems. The project integrates intelligent systems such as thermal deaeration and boiler feedwater optimization, establishing a highly efficient, low-carbon energy cycle. This technology maximizes waste heat utilization from gas treatment and contributes to the vision of a "zero-carbon mine."

The success of the Coal Mine waste heat boiler selection exemplifies comprehensive considerations, from technical adaptability and system integration to lifecycle benefits. Below is an in-depth analysis and key takeaways from the project:

Technical Highlights: Why Choose Vertical Natural Circulation Boilers?

During boiler selection, Xi'an Yurcent analyzed layout structures and circulation principles based on the client's steam quality requirements. A multidimensional comparison between vertical vs. horizontal layouts and natural vs. forced circulation led to the adoption of vertical natural circulation boilers, offering three core advantages:

1. High-Efficiency Heat Transfer, Energy & Cost Savings

• Vertical flue design aligns with natural circulation, where gas and tube flow directions are consistent.
• Driven by steam-water density differences, heat transfer efficiency improves significantly—no extra circulation pumps or electricity costs.
• Boiler thermal efficiency exceeds 89%.

2. Compact Layout, Superior Adaptability

• Space-saving: Ideal for confined mining areas; two vertical boilers occupy just 60 m², 30–50% less than horizontal models.

3. Reliability & Smart Control

• Near-zero failure rates due to density-driven circulation.
• AI-powered monitoring of drum water levels and steam pressure ensures 24/7 stable operation.
• Innovations: Intelligent, Industry-Wide Synergy. Yurcent's team collaborated with suppliers to optimize the system for zero energy waste:
• Material Upgrade: High/low-temperature superheaters use 12Cr1MoVG alloy steel, while evaporators employ 20G steel, extending equipment lifespan.
• Smart Control:

• • Dual-redundant drum water monitoring prevents shutdowns from single-point failures.
  • PID algorithms dynamically adjust feedwater pumps and blowdown systems to match steam load fluctuations, maintaining peak efficiency.

• Modular Maintenance: Horizontal access channels and vertical tube bundles cut downtime by 40%.

Operational Results: From Theory to Practice

Since commissioning, the system has delivered exceptional performance through a full heating season:

• Waste gas temperature reduced from 950°C to <100°C through graded recovery.
• Steam output reliably meets dual needs:
  • Power generation: 3.82 MPa, 450°C
  • Heating: 1.0 MPa, 185°C (fluctuation <±3%)
• Supports mine-wide applications: cooking, bathing, space heating, and shaft insulation.