I. Application Background: New Blue Ocean in the Carbon Neutrality Era

With the acceleration of global carbon neutrality, carbon capture, utilization, and storage (CCUS) technology is widely recognized as a key path to achieve low-carbon transformation of fossil energy. Under the guidance of China's "Dual Carbon" strategic goals, CCUS has moved from the technical preparation stage into a new cycle of large-scale demonstration and commercial promotion.

In 2022, the annual injection volume of the four major CCUS engineering demonstration zones and six pilot experimental areas under Sinopec reached over 1 million tons. China's first 1 million ton, 109 km high-pressure, ambient temperature dense-phase CO₂ transportation pipeline — the "Qilu Petrochemical - Shengli Oilfield" 1 million ton CCUS project — has been completed and put into operation, transporting over 1 million tons of CO₂ annually from industrial emission sources to oilfield storage points through a 109 km pipeline. In this grand industrial chain, every link from capture, transportation to injection and storage relies on a core supporting equipment — CO₂ Injection and Monitoring System.

This system undertakes two critical missions: first, it pressurizes low-pressure CO₂ (gaseous or liquid) to the required process pressure for efficient transportation and injection; second, it collects flow data and monitors pressure in real time during injection, ensuring accurate measurement and controllable processes. Whether in supercritical CO₂ reaction research in laboratories, pressure station operations for hundreds of kilometers of pipelines, or oil field gas injection and storage operations, the CO₂ injection and monitoring system serves as an "invisible central hub" that ensures the safety, efficiency, and traceability of the entire chain.

II. Current Main Difficulties and Technical Challenges

Although the CCUS industry has broad prospects, the CO₂ injection and monitoring field still faces multiple technical obstacles, becoming a key bottleneck restricting industry scaling.

1. Pressure Challenges Caused by Complex Phase States

Carbon dioxide can be liquefied by pressurization at normal temperature, and further pressurization leads it into a supercritical state (critical temperature 31.1°C, critical pressure 7.38 MPa). In practical applications, CO₂ may exist in gaseous, liquid, or supercritical states, with significant differences in density, viscosity, and compressibility among different phase states. Traditional pressure boosting equipment struggles to adapt to these multi-phase conditions, often leading to issues such as cavitation, large flow pulsation, and seal failure.

2. Measurement Challenges in Ultra-High Pressure and Wide Range

The wellhead pressure of CCUS injection wells typically reaches 15-40 MPa, while some supercritical experimental platforms require pump outlet pressure ≥25 MPa. Under such high pressure, traditional mass flow meters and pressure sensors face problems such as reduced accuracy, zero drift, and insufficient pressure resistance. Meanwhile, the injection process involves conflicting demands between "precise small flow measurement" and "rapid large flow injection," making it difficult for a single instrument to achieve high-precision measurement across a wide range.

3. Reliability Risks Under Low-Temperature and Corrosive Conditions

Liquid CO₂ can reach temperatures as low as -24°C (as seen in the Qilu Petrochemical-Shengli Oilfield project), while in supercritical state, it needs to be heated above 15°C. Severe temperature changes impose strict requirements on pipeline sealing materials and sensor temperature resistance. More seriously, CO₂ dissolving in water forms carbonic acid, which corrodes metal components in humid environments. CCUS well corrosion monitoring data shows that under complex conditions like gas-water alternation and supercritical states, the corrosion rate of CO₂ can reach 5-10 times that of conventional environments.

4. Insufficient Level of Automation and Intelligence

Currently, some injection stations still rely on manual valve adjustment and meter reading, resulting in high labor intensity and low efficiency, with difficulty in accurately controlling the injection volume per well. Practical experience from Shengli Oilfield shows that in traditional manual operation mode, the issue of "unbalanced injection" is prominent, affecting the effectiveness of CO₂ storage and oil displacement efficiency.

5. Dual Pressures of Safety Explosion Protection and Leak Monitoring

Although CO₂ is not flammable or explosive, high concentration exposure poses toxic risks to humans. Studies show that CO₂ can reach toxic levels before oxygen is significantly displaced. The injection system operates under high-pressure conditions, and once a leak occurs, it can cause personnel injury or even serious safety accidents. Therefore, the equipment must have complete overpressure protection, leak early warning, and emergency shut-off functions.

III. Technical Development Directions

Facing the above challenges, CO₂ injection and monitoring technology is accelerating its evolution in the following directions:

1. Wide Adaptability Pressure Boosting Technology

Developing multi-condition pressure boost pumps capable of handling gaseous, liquid, and supercritical CO₂. Using non-electric solutions such as pneumatic gas boosters to eliminate the risk of electrical sparks at the source, while achieving stable output under low inlet pressure.

2. Intelligent Closed-loop Control

Learning from the successful experience of the "Multi-branch Flow Automatic Regulation System" in Shengli Oilfield, integrating the CO₂ injection and monitoring system deeply with the station control system. Through closed-loop linkage between pressure sensors and pressure boosters, achieving automatic constant pressure control and multi-channel balanced injection, transitioning from "manual rough" to "intelligent precision."

3. High-Precision Wide-Range Measurement

Using high-precision instruments such as Coriolis mass flow meters, combined with temperature and pressure compensation algorithms, maintaining a measurement accuracy of ≤±0.5% across the full range (from milliliters per minute to kilograms per minute). At the same time, configuring redundant pressure monitoring to ensure safe operation of the system when sensors fail.

4. Cold-Resistant and Corrosion-Resistant Design

Key pressure-bearing components are made of 316L stainless steel or higher-grade corrosion-resistant alloys. Sealing parts use special materials resistant to low temperatures and CO₂ swelling (such as PTFE, PCTFE). For low-temperature conditions, configure heating or heat exchange units to ensure CO₂ reaches the appropriate temperature before entering the injection system.

5. Digitalization and Traceability

Injection process data (pressure, flow, temperature, cumulative injection volume) is stored locally and synchronized to the cloud, meeting the MRV (Monitoring, Reporting, Verification) requirements of CCUS projects. Data is traceable and tamper-proof, providing credible evidence for carbon trading and policy subsidies (such as the 45Q tax credit).

IV. Core Technology: Deep Integration of Pneumatic Gas Boosting and Intelligent Control

An advanced CO₂ injection and monitoring system demonstrates its core competitiveness through the following four technical modules:

1. Pneumatic Gas Boosting Unit

Using a pneumatic gas booster as the core power component, driven by compressed air (0.4-0.8 MPa), it outputs high-pressure CO₂ according to a certain pressure ratio. The advantages of this technical route include:

• Inherent Safety: No electric drive, no risk of spark generation
• Self-adaptive Start/Stop: Automatically stops when the set pressure is reached, and automatically repressurizes when the pressure drops
• Broad Pressure Range: By replacing the booster or using a dual-stage series configuration, output pressure can reach more than 2 MPa to 50 MPa

2. High-Precision Flow Acquisition and Pressure Monitoring Unit

• Flow Meter: Using a mass flow meter to directly measure mass flow, unaffected by temperature and pressure changes
• Pressure Sensor: Configuring redundant pressure transmitters (e.g., WIKA brand, accuracy 0.25% FS) to monitor pressure at key points before and after the pump and along the pipeline in real time
• Data Fusion: Real-time collection of flow, pressure, and temperature data through PLC or embedded systems, performing temperature and pressure compensation and cumulative calculation

3. Intelligent Control System

• Pressure Setting and Closed-loop Control: After the operator sets the target pressure, the control system automatically adjusts the driving air pressure or on/off frequency of the booster to achieve precise pressure stabilization
• Multi-parameter Interlocking Protection: Equipped with three-level alarms and emergency shutdown functions for overpressure, overheating, and leakage
• Human-Machine Interaction: A touch screen interface intuitively displays key parameters such as instantaneous flow, cumulative flow, current pressure, and set pressure

4. Safety and Structural Design

• Pipeline Connection: Using non-welded high-pressure rigid pipe connections (compression fitting or conical surface sealing) to eliminate the risk of leaks caused by welding defects
• Pressure Relief Valve and Burst Disk: Dual overpressure protection to ensure pressure release even if the control system fails
• Integrated Cabinet: Compact structure, convenient for mobile or fixed installation, meeting the protection requirements of explosion-proof areas

V. HOFUTECH Product Advantages: Defining Standards with Professionalism

In this emerging field of CO₂ injection and monitoring, HOFUTECH, with its deep technical accumulation and forward-looking product layout, has built a significant core competitive advantage:

1. Full-Condition Pressure Coverage Capability

HOFUTECH's CO₂ injection and monitoring system uses a specialized CO₂ pneumatic booster, optimized for the phase change characteristics of CO₂:

• Supports direct pressure boosting of gaseous CO₂ (inlet pressure ≥ 2 MPa) and pressure boosting of liquid CO₂ (inlet pressure at saturation vapor pressure)
• Maximum output pressure can reach 50 MPa, fully covering various scenarios including laboratory research, industrial pipeline transport, and oilfield injection
• Wide flow range: From micro-experimental level (ml/min) to industrial level (kg/min) can be configured

2. Measurement Accuracy and Data Credibility

The system integrates high-precision mass flow meters and redundant pressure sensors:

• Flow measurement accuracy: ≤ ±0.5% FS
• Pressure acquisition accuracy: ≤ ±0.25% FS
• All data supports real-time recording and historical traceability, meeting the strict MRV requirements of CCUS projects

3. Intelligent Closed-loop Control, Cost Reduction and Efficiency Improvement

Learning from the successful practice of "multi-branch flow automatic regulation" in Shengli Oilfield, HOFUTECH system is equipped with constant pressure and constant flow control algorithms, enabling automatic balancing of multiple injection ports. Operators only need to set target parameters, and the system can automatically complete the entire process of pressure boosting, pressure maintenance, and pressure replenishment, significantly reducing manual intervention and maintenance costs.

4. Safety Design Throughout

• All pipeline systems use 316L stainless steel and non-welded rigid pipe connections, eliminating the risk of leakage from the source
• Equipped with double overpressure protection with safety valves and bursting discs
• Optional CO₂ leak detection sensors for real-time monitoring of environmental CO₂ concentration,联动 ventilation and alarm
• All electrical components are selected according to explosion-proof area requirements

5. Modular and Customization Capabilities

HOFUTECH products adopt a modular design, allowing flexible combination of pressure boosting modules, measurement and control modules, and heat exchange modules according to user needs. Whether it is a small test platform for laboratories or a large injection skid equipment for oilfields, they can be delivered quickly.

6. Alignment with Industrial Upgrading Trends

As CCUS demonstration projects in Shengli Oilfield, Changqing Oilfield, and other areas undergo intelligent upgrades, unmanned operation and remote maintenance have become a trend. HOFUTECH systems support multiple communication interfaces such as 4-20 mA, RS485, and Ethernet, seamlessly integrating with station control systems or cloud platforms, providing a solid data foundation for the digital management of the entire CCUS chain.

Conclusion

From supercritical reaction research in laboratories, to the power heart of hundreds of kilometers of pipelines, and finally to the underground carbon storage injection in oil fields, the CO₂ injection and monitoring system spans each key node in the CCUS industrial chain. HOFUTECH, with its pneumatic gas boosting technology as the core, deeply integrates intelligent control and safety design, providing precise, reliable, and efficient core equipment support for this green industry. Under the grand narrative of carbon neutrality, HOFUTECH is leveraging its professionalism to ensure the safe journey of every ton of CO₂.