Against the backdrop of advancing the 'Dual Carbon' goals and increasingly stringent environmental regulations, the emission control and resource recovery of waste gases such as high-value solvent vapors and volatile organic compounds (VOCs) from industrial production have become core demands for enterprises pursuing green transformation.

Traditional condensation technologies are limited by cooling temperature and struggle to meet ultra-low emission requirements. While incineration can meet discharge standards, it suffers from high carbon emissions and constraints on safety distances.

Building on its technological expertise in gas separation and refrigeration, Tianjin Tianchen Jijing Technology Co., Ltd. (hereinafter referred to as 'Tianchen Jijing') has launched a liquid nitrogen condensation recovery solution. Supported by its core -196°C cryogenic technology, the solution achieves both efficient waste gas purification and resource recycling, providing a compliant and economical environmental upgrade path for the chemical, petroleum, pharmaceutical and other industries.

Liquid Nitrogen Condensation & Recovery Solution

I. Core Positioning: Targeted Solution to Industrial Waste Gas Recovery Pain Points

TT‑EE’s liquid nitrogen condensation and recovery solution is positioned as “ultra-low temperature deep purification + high-value resource recovery”. It targets ultra-low boiling point and high-concentration waste gas treatment scenarios that cannot be covered by conventional technologies, achieving three major breakthroughs:

Breakthrough in temperature limit
Using liquid nitrogen as the cooling source, waste gas is cooled to -120°C ~ -170°C, enabling highly efficient condensation of low-boiling components such as acetone and methanol.
Breakthrough in efficiency bottleneck
Waste gas treatment efficiency reaches above 97%, with stable emission concentration below 25 mg/m³, far exceeding the Emission Standard of Air Pollutants for Oil Storage Terminals (GB 20950‑2020) and stricter local regulatory requirements.
Breakthrough in benefit dilemma
Through the recovery of oil, solvents and other resources, plus reuse of nitrogen gasified from liquid nitrogen, the solution achieves coordinated improvement of environmental governance and economic benefits.

This solution is widely applicable to ultra-high-concentration solvent vapor emissions from storage tanks, reactors, distillation columns, etc., as well as the recovery of evaporative gas, pressure relief gas and residual pressure gas from high-value liquid products such as natural gas, ethylene and liquid argon. It covers petrochemical, fine chemical, pharmaceutical manufacturing, coating and other industries, and is especially suitable for flammable and explosive waste gas treatment scenarios with high safety and purity requirements.

II. Core Architecture: Three-Stage Cryogenic Process + Intelligent Control System

Adopting a modular integrated design, the solution consists of seven core modules:

waste gas collection system, pretreatment system, multi-stage condensation system, gas-liquid separation system, resource recovery system, nitrogen reuse system and intelligent control system.

It forms a full-process treatment chain:

closed collection → step-by-step cooling → deep condensation → resource reuse → compliant discharge.

(1) Core Process: Three-Stage Cryogenic Condensation + Cold Energy Recovery

The solution uses an innovative three-stage condensation process:

primary cooling → intermediate cooling → deep cooling, combined with dual-channel frost-defrost alternating operation, to achieve high-efficiency cold energy utilization and optimized energy consumption.

Industrial waste gas is first sent to a gas-liquid separator to remove entrained liquid impurities.
Pre-treated waste gas enters the primary cooling stage, pre-cooled by low-temperature nitrogen from liquid nitrogen gasification to recover cold energy.
It then enters the intermediate cooling stage for further cooling, separating most medium and high-boiling components.
Finally, it enters the deep cooling stage. At -120°C ~ -170°C, low-boiling components are fully condensed into liquid for gas-liquid separation.

A cold energy recovery process recovers cold from the cryogenic tail gas, significantly reducing liquid nitrogen consumption.

Practical applications verify:

Only 2–6 kg of liquid nitrogen is consumed to recover 1 kg of oil;
Unit power consumption is as low as 0.05 kWh/m³ of waste gas;
Energy consumption is reduced by more than 30% compared with conventional cryogenic technologies.

High-purity nitrogen from liquid nitrogen gasification can be directly fed into the user’s nitrogen pipe network for nitrogen sealing, inerting and other production processes, realizing cascade energy utilization.

(2) Key Equipment: Modular Skid-Mounted Design + Corrosion-Resistant High-Efficiency Components

Core equipment adopts a skid-mounted integrated design, with heat exchangers, condensers, liquid nitrogen vessels and liquid collectors integrated in a cold box.

The cold box features a double-layer vacuum insulation structure:

Inner layer: 304 stainless steel
Outer layer: Q235 steel
Middle: pearlite insulation
Vacuum degree ≤ 5×10⁻³ Pa
Daily evaporation rate ≤ 0.5%

Heat exchangers are tubular, made of 316L stainless steel or PTFE coating, suitable for corrosive waste gas with high heat exchange efficiency and low pressure drop.

Condensers are equipped with precise temperature control modules that dynamically adjust cooling temperature according to waste gas composition.

For small-to-medium or mobile applications, a push-behind micro recovery unit is available, which can be moved directly to tanks or tank trucks for quick connection and operation, with small footprint, especially suitable for LNG refueling stations and small chemical plants.

(3) Intelligent Control: Full-Process Automation + Safety Interlock Protection

The solution is equipped with a DCS + PLC intelligent control system, integrated with a 7-inch touch screen and high-precision sensors, realizing full-process automatic operation.

The system monitors inlet flow, concentration, temperature, pressure and other key parameters in real time, and dynamically adjusts liquid nitrogen consumption.

When the liquid collector is full, the system automatically alerts and controls liquid output, and starts the air-boosted vaporizer for pressurized delivery.

For safety, the system has multiple interlock protection mechanisms:

Explosion-proof control cabinet (Ex dIIBT4)
On-line purity analyzer
Safety valves and helium leak detection system
Oxygen concentration monitoring to prevent hypoxia risk

The system automatically alarms and shuts down if nitrogen purity is below 99.999% or pressure is abnormal, ensuring full-range production safety.

III. Core Advantages: Triple Empowerment in Technology, Economy and Safety

(1) Technical Advantages: Cryogenic Core + Wide Adaptability

Supported by TT‑EE’s expertise in gas separation and low-temperature refrigeration, the solution uses -196°C ultra-low temperature technology to break through conventional condensation limits.

It can handle difficult-to-condense components with boiling points below -50°C, and has strong adaptability to high-concentration, complex-component waste gas.

Modular design ensures short installation cycle; capacity can be flexibly expanded according to user throughput.

(2) Economic Advantages: Resource Recovery + Energy Consumption Optimization

Dual resource recovery creates obvious economic benefits:

Recovered solvents and oils can be directly reused in production. For LNG recovery, gross profit can exceed 1.5 RMB per kg.
Reuse of high-purity nitrogen reduces external nitrogen purchase costs.

Comprehensive benefit can reach 0.5 RMB per m³ of oil and gas treated.

Most enterprises can recover investment within 1–3 years.

(3) Safety Advantages: Flameless Process + Fully Closed Control

Using physical condensation, the process is flameless, with no fire risk — ideal for flammable and explosive waste gas such as toluene and xylene.

Waste gas is treated in fully closed pipelines and equipment, with no secondary pollution.

Recovered materials have high purity and can be reused without secondary purification.

IV. Application Value: Supporting Green Transformation + Aligning with National Policies

“Liquid nitrogen cryogenic organic solvent recovery technology” is included in the CPCIF Green & Low-Carbon Process Catalogue (2021 Edition).

The solution strongly supports the national “Dual Carbon” goals and environmental policies, helping enterprises meet emission standards and avoid environmental penalties.

It improves raw material utilization, reduces production costs and enhances market competitiveness.

Modular and intelligent design drives industrial environmental protection equipment toward high efficiency, low carbon and intelligence.

Typical Case

A chemical enterprise applied the TT‑EE solution to treat acetone waste gas from reactors at 5000 m³/h:

Treatment efficiency: 98%
Outlet concentration: 18 mg/m³
Annual acetone recovery: 120 tons → direct benefit over 4 million RMB
Annual nitrogen reuse: 80,000 m³ → saving over 300,000 RMB

A win-win of environmental and economic benefits.

V. Service System: Full Lifecycle Support

TT‑EE provides full lifecycle services:

Pre-sales: On-site investigation, working condition analysis, customized solutions.
During sales: Equipment installation guidance, commissioning and optimization.
After-sales: 24-hour response, maintenance, spare parts, technical upgrades, operator training.

Relying on import & export and technical exchange advantages, TT‑EE can introduce international advanced cryogenic technologies and components to provide global technical support.

Conclusion

As green development becomes the core theme of industrial transformation, TT‑EE’s liquid nitrogen condensation and recovery solution, with the innovative model of “cryogenic technology + resource recycling”, breaks the “input-only no-output” dilemma of traditional environmental governance.

It provides enterprises with a compliant, efficient and economical green upgrade path.

Moving forward, TT‑EE will continue to deepen R&D in low-temperature condensation and gas separation, continuously optimize energy consumption and efficiency, and help more industries achieve coordinated progress in environmental governance and high-quality development.

Liquid Nitrogen Condensation Recovery Solution: Empowering Green Resource Utilization with Cryogenic Technology