Gas Turbine SCR DeNOx System Successfully Commissioned for Distributed Energy Project

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Recently, a gas turbine flue gas DeNOx system engineered by Hebei Hanlan Environmental Technology Co., Ltd. was successfully commissioned and has now entered stable long-term operation in a natural gas distributed energy (CCHP) project.

Unlike standard turnkey deployments, this project required a high level of on-site adaptation due to the flexible operating mode of the gas turbine and heat recovery system.

 

From Site Investigation to Final Design: Engineering Based on Real Conditions

At the early stage, our engineering team conducted multiple on-site inspections rather than relying solely on design assumptions.

Key challenges identified included:

Fluctuating turbine load conditions

Variable exhaust temperature (especially in winter operation)

Limited reserved space in the HRSG for SCR installation

Strict internal emission control targets beyond regulatory requirements

Based on these findings, we iteratively optimized the system design over several rounds.

Instead of a conventional one-to-one configuration, we implemented a 3-unit shared scr system, significantly reducing footprint and investment while maintaining performance.

 

System Configuration and Integration

The final system includes:

Urea thermolysis and dosing system

SCR reactor and catalyst modules

Electrical & instrumentation control system

Complete auxiliary components (valves, pipelines, flanges, spare parts, etc.)

Hebei Hanlan delivered full-scope services, including design, manufacturing, commissioning, and operator training, ensuring that the system could be independently operated by the client team after handover.

 

Real Operating Performance (Verified Data)

After commissioning, the system has been operating under continuous real load conditions.

Measured performance shows:

NOx outlet concentration: ≤ 30 mg/Nm³

DeNOx efficiency: ≥ 90%

Ammonia slip: ≤ 3 ppm

System availability: ≥ 98%

 

More importantly, during actual operation:

Even when the gas turbine load fluctuates between 30%–95% BMCR, the scr system can be switched on instantly without affecting boiler operation.

This was a key concern raised by the client before implementation — and has now been fully resolved in practice.

 

Handling Temperature Fluctuations: A Practical Challenge Solved

One of the most critical issues in this project was the wide temperature range of the exhaust gas:

Winter conditions: ~360°C

Normal operation: ~400°C

Peak conditions: up to 450°C

Instead of designing for a narrow optimal window, the system was engineered to maintain stable performance across the full 360–450°C range.

During trial operation, the system successfully handled short-term high-temperature exposure (near 450°C) without:

Catalyst deformation

Performance degradation

System instability

Why Urea-Based SCR Was Selected (Instead of Ammonia)

From a purely technical perspective, both ammonia and urea could achieve similar NOx removal efficiency.

However, based on client safety requirements and site logistics, we selected a urea-based SCR solution:

Safer storage and transportation

No need for hazardous ammonia handling infrastructure

Easier compliance with site safety regulations

This decision significantly reduced operational risk for the client — a factor often underestimated in early-stage planning.

 

Catalyst Design: Focus on Long-Term Reliability

In previous similar projects, we observed that catalyst performance degradation is often caused by:

Dust accumulation

Surface fouling

Thermal stress

To address these real-world issues, this project adopted:

High-durability, anti-poisoning catalyst materials

Smooth surface design to prevent ash deposition

Modular structure for easy replacement and maintenance

The catalyst is designed for:

Continuous operation at 300–420°C

Service life ≥ 24,000 hours after initial ammonia injection

Additionally, it can withstand short-term exposure to 450°C for up to 5 hours without structural or performance damage.

 

Adaptation to Site Constraints

Another practical constraint was the limited reserved space in the HRSG:

Available SCR section: 2000 × 2400 × 2900 mm

Instead of requiring structural modification, the SCR reactor was custom-designed to fit exactly within this space, avoiding additional construction work and reducing project downtime.

 

Project Outcome: Stable, Compliant, and Operator-Friendly

After extended operation, the system has demonstrated:

Stable emission compliance with both national and internal standards

Minimal impact on existing turbine and boiler operation

High reliability with low maintenance demand

From the client’s feedback:

“The system runs smoothly even during load changes. What we value most is that it doesn’t interfere with our normal operation.”

 

Conclusion

This project demonstrates that an effective SCR DeNOx system is not just about achieving emission targets on paper.

It requires:

Deep understanding of real operating conditions

Flexible engineering design

Reliable catalyst performance

And full lifecycle service capability

Hebei Hanlan’s approach — combining field experience with tailored engineering — ensured that the system not only met emission standards, but also performed reliably in long-term real-world operation.