I. Technical Principles and Core System Composition

As a large-scale industrial thermal energy equipment, the 150T hydrogen boiler's core principle is the conversion of chemical energy into thermal energy through a vigorous oxidation reaction between hydrogen and oxygen in the burner, thereby heating water to produce steam. Its system composition comprises four main modules:
1. Combustion System
Utilizing diffusion combustion technology, hydrogen is injected into the furnace in a cone shape through a dedicated annular burner, forming a stable flame with premixed air. The system is equipped with a proportional regulating valve group, which can adjust the hydrogen to air flow ratio in real time (typically 1:3.5-4.2) to ensure a combustion efficiency of over 98%. The case study from Shanghai Chlor-Alkali Chemical Co., Ltd. shows that its 150T boiler uses a symmetrical dual-burner layout, with each burner handling a hydrogen capacity of 75,000 Nm³/h, and the flame temperature controlled within the 1800-2000℃ range.
2. Safety Control System A three-level protection mechanism is implemented:
Ignition Safety: A two-stage ignition procedure is adopted. The auxiliary burner is first ignited with liquefied petroleum gas (LPG). After the flame monitor confirms stability, the main hydrogen burner is automatically switched on.
Pressure Management: The hydrogen supply pressure is strictly controlled between 0.8-1.2 MPa. A three-valve-one-port system (double shut-off valve + nitrogen replacement valve + exhaust valve) ensures rapid isolation in case of pressure abnormalities.
Explosion-proof Design: The furnace is equipped with eight explosion-proof doors, with a total explosion relief area of ​​12 m², meeting NFPA standards. The burner is equipped with a water-sealed check valve, capable of withstanding a 100 mm water column backflow pressure.
3. Heat Recovery System
Employs a four-section heating surface layout:
Radiant Section: Water-cooled walls absorb radiant heat from combustion, achieving an efficiency of 65%.
Convection Section: Serpentine tube bundles enhance convective heat transfer in flue gas.
Economizer: Annular coil structure reduces exhaust gas temperature to below 150℃.
Steam-Water Separator: Dual design of cyclone separation and wire mesh demister, achieving a steam quality of 99.8%.
4. Automated Monitoring System
Based on a PLC-based DCS control system:
Multi-parameter linkage control: Real-time monitoring of over 20 parameters including steam pressure (1.0-3.8MPa), water level (±50mm), and hydrogen flow rate (0-560m³/h).
Intelligent protection functions: Overpressure interlock (automatic shutdown when pressure ≥4.0MPa), low water level protection (emergency water replenishment triggered when water level ≤-100mm), hydrogen leak detection (alarm when combustible gas concentration ≥4%).
Remote operation and maintenance module: Supports real-time viewing of operating data via mobile APP; historical curve storage period up to 3 years.

II. Safety Features and Risk Control

1. Explosion Limit Control
The explosion limits of hydrogen are 4%-75% (volume concentration). The 150T boiler mitigates risk through three main measures:
* **Inert Gas Replacement:** Nitrogen purging is used during start-up and shutdown to ensure furnace oxygen content ≤2%.
* **Pressure Balance Control:** A pressure regulating valve is installed in the hydrogen buffer tank to maintain system pressure fluctuations ≤±0.05MPa.
* **Area Isolation Design:** The boiler body and auxiliary equipment are located outdoors; the control room uses an explosion-proof structure; and electrical wiring is laid in steel conduits.
2. Backfire Prevention Technology
To address the rapid combustion speed of hydrogen (flame propagation speed reaches 3m/s), the following measures are adopted:
* **Minimum Pressure Maintenance:** A pressure regulating valve is installed at the burner inlet to ensure that the hydrogen pressure is always 0.02MPa higher than the air pressure.
* **Flame Stabilizer:** A cyclone separator is installed at the burner outlet to form a stable backflow zone.
* **Rapid Cut-off Device:** The hydrogen pipeline is equipped with a pneumatic emergency cut-off valve with an action time ≤0.3 seconds.
3. Material Selection Standards
Key components use special materials:
Burner nozzles: Hastelloy C-276, temperature resistance 1200℃
Furnace lining: Lightweight insulating brick + aluminum silicate fiber felt composite structure, surface temperature ≤60℃
Hydrogen pipeline: 316L stainless steel, wall thickness ≥8mm, welded joints undergo 100% radiographic inspection

III. Engineering Application Case Analysis

Case 1: Shandong Aluminum Group Chlor-Alkali Plant
Project Scale: 150T/h hydrogen boiler (commissioned in 2004)
Operating Data:
Annual hydrogen consumption: 21 million Nm³
Steam output: 1.2 million tons/year
Thermal efficiency: 91.5%
Economic benefits: Annual savings of 84,000 tons of standard coal, reduction of CO₂ emissions 220,000 tons
Technical Highlights:
* Innovative use of a combined hydrogen and electrolytic alkaline waste heat recovery system, reducing flue gas temperature from 220℃ to 130℃.
* Development of a hydrogen pressure fluctuation compensation algorithm; when the electrolyzer load fluctuates by ±20%, the steam pressure fluctuation is ≤±0.1MPa.
Case 2: Xinpu Chemical (Jiangsu Taixing) Co., Ltd.
Project Scale: 150T/h hydrogen boiler (commissioned in 2012)
Safety Improvements:
* Added an online hydrogen purity analyzer; automatically shuts down the boiler when the oxygen content is ≥0.5%.
* Modified the burner to a split structure, physically isolating the ignition system from the main burner.
* Established a three-dimensional flow field simulation model to optimize the boiler. The furnace structure reduces CO emission concentration to below 50 mg/m³.

IV. Technological Development Trends

Intelligent Upgrade: Introducing AI visual detection technology to achieve real-time flame morphology recognition and combustion state prediction.
Material Innovation: Developing ceramic matrix composite burners, extending service life to 50,000 hours.
System Integration: Constructing a combined hydrogen-steam-power generation system, improving overall energy efficiency to 95%.
Modular Design: Developing standardized boiler modules, with single-unit processing capacities covering the 50-300 T/h range.
This technology has formed a complete industrial chain, with over 20 domestic companies mastering core manufacturing technologies, and the equipment localization rate exceeding 90%. With the decreasing cost of green hydrogen production (expected to drop to 15 yuan/kg by 2030), the promotion and application of hydrogen boilers in industries such as chemical, metallurgy, and building materials will enter a period of explosive growth.