Addressing challenges in the ethylene industry including complex processes, highly coupled control systems, and stringent safety and environmental requirements, Sinopec has established the world’s first digital twin-based intelligent ethylene plant at Zhongke Refining and Chemical by leveraging its proprietary megaton ethylene complete technology and industrial internet platform "Sinopec Smart Cloud" to deeply integrate technologies such as digital twins and intelligent control. By establishing a 3-layer architecture of "physical space - interaction layer - digital twin space", key technical barriers including high-fidelity hybrid modeling, multi-modal model fusion, and development of intelligent equipment have been overcome. This has resulted in a full-process intelligent operation system covering efficient resource utilization, production optimization, equipment health management, and safety and environmental protection. The achievement represents a dual breakthrough in both key technologies and operational models, providing a replicable systematic solution for the intelligent transformation of the ethylene industry.

This article briefly summarizes the overall situation of SINOPEC’s ethylene business in 2025 from the aspects of safety and environmental protection, optimization of feedstock and operation, energy conservation and consumption reduction, technological breakthroughs, long-term operation, and maintenance. The work objectives and key tasks for SINOPEC’s ethylene production in 2026 are proposed.

This paper provides a comprehensive overview of the operational status of PetroChina's ethylene business in 2025. It systematically reviews the performance achievements of various production facilities concerning core indicators such as ethylene output, yield, and energy consumption. Moreover, it conducts an in-depth analysis of the achievements made in areas such as feedstock optimization, extended operational cycles, turnaround management, and technological upgrades. Furthermore, it defines the key tasks and implementation arrangements for PetroChina's ethylene business in 2026.

The petrochemical industry is an important pillar industry in China, providing the society with abundant energy and chemical products. Petrochemical equipment is characterized by high temperature, high pressure and high corrosion. Through the inspection of equipment, production safety and operational efficiency of units can be guaranteed. Digital delivery builds an information organization centered on equipment tag numbers. Through the digital delivery platform, it associates data, documents, and 3D model information related to the equipment, enabling convenient query and browsing of equipment information. By establishing an interface between the digital delivery platform and the equipment inspection and maintenance system, not only can the rapid query of reference data be achieved, but also the three-dimensional visualization management of inspection can be realized, thereby enhancing the operation and maintenance efficiency of enterprises. This article systematically elaborates on the application path and technical implementation methods of digital delivery in equipment inspection and maintenance from aspects such as equipment classification configuration, engineering data information interaction, engineering documentation information interaction, and 3D model information interaction, providing theoretical reference and practical guidance for petrochemical enterprises to promote digital transformation.

As the core equipment of ethylene plant, quench water tower is mainly used to further reduce the temperature of cracking gas to near ambient temperature and achieve the separation of water, heavy aromatic hydrocarbons, and heavy tar. The continuous increase in packing pressure difference in quench water tower not only increases the energy consumption of cracking gas compressor, but also poses risks of tower internal collapse and tower flooding, which can lead to compressor interlock shutdown, severely restricting the long-term operation of ethylene plant. This article focuses on the problems of packing scaling and increased pressure difference in quench water tower. Online flushing is adopted for the lower packing to reduce the pressure difference from 8.0 kPa to 3.6 kPa. Reasons for packing scaling are analyzed, and reasonable measures are proposed to prevent the scaling in quench water tower.

In recent years, many ethylene plants have encountered the problem of dew point rise at the outlet of regeneration gas heater, and the causes of dew point rise have not been found through various on-site investigations. The dew point at the outlet of the regeneration gas heater in the 600 kt/a ethane-to-ethylene plant in Tarim was also detected, and the same phenomenon was found. In order to find the root cause, heat exchanger leakage investigation, comparison of similar plants, material composition changes, process parameter verification, and material investigation were carried out to find the causes of the final dew point rise, and some suggestions were put forward for the operation.

Pressure swing adsorption (PSA), as an effective gas separation and purification technology, has the advantages of flexible process operation and high degree of automation. However, the recovery of hydrogen through PSA will result in certain hydrogen losses, mainly in the regeneration stage of the adsorbent. The hydrogen loss rate of PSA can be reduced by extending the adsorption time or reducing the hydrogen loss during the regeneration stage. Under the premise of ensuring product quality, stabilizing and optimizing PSA operation parameters and setting the operating time within a reasonable range are necessary to fully utilize the role of the adsorbent and minimize the hydrogen loss rate of PSA while improving hydrogen yield.

During the overhaul of a butadiene unit of a petrochemical company in 2024, a large amount of black slag polymer was found in the first layer packing distributor at the top of post-wash tower for extractive distillation system, blocking the liquid distributor and affecting the separation effect of the extractive distillation system. Meanwhile, the bypass line on the tube side of solvent heat exchanger E-1130A was found to be completely filled with polymers. This paper analyzes the causes of polymer generation, and proposes some measures for preventing polymerization in the extractive distillation system combined with production practices and process control indicators, so as to extend the operation cycle of the unit.

This paper introduces the process flow and functions of compression unit in ethylene plants, as well as the principles and harms of quench water emulsification. The correlation mechanism between the operation process fluctuations and operation condition changes of compression unit and the quench water emulsification is analyzed in detail. In order to reduce the adverse effect of compression unit on quench water emulsification and ensure the stable and efficient operation of ethylene plant, some measures are proposed to optimize the operation of compression unit and strengthen the process control.

During the switching of cracking gas dryer in the 220 kt/a ethylene plant of a petrochemical company, sometimes the cracking gas compressor may experience fluctuations in suction drum pressure and cracking gas flow, disrupting the inter-stage pressure balance. This may lead to fluctuations in the bearing temperature, vibration, and displacement of the cracking gas compressor, significantly impacting the long-term operation of the cracking gas compressor and the safe and smooth production of the entire plant. This article analyzes the causes of the above problems, and proposes some solutions to ensure the stable operation of the plant.

Critical flow Venturi nozzle (CFVN) is a standardized gas flow distribution device widely adopted in the petrochemical industry due to its simple structure and excellent stability. This article summarizes the critical applications of CFVN in the distribution of feedstock across the radiation section tubes of ethylene cracking furnaces, and elaborates on its importance in ensuring the uniform distribution of cracking feedstock, maintaining the stable operation of cracking furnace, and extending the operating cycle. The working principle of CFVN based on critical flow condition (where flow velocity reaches sonic speed) is introduced in detail, emphasizing that a back pressure ratio (outlet pressure / inlet pressure) below the critical value is the key condition for achieving uniform distribution. Utilizing a combination of industrial case studies with specialized software and Computational Fluid Dynamics (CFD) simulations, this article investigates the flow characteristics of compressible turbulent within the CFVN. The analysis focuses on the significant impact of throat diameter and diffuser length on the back pressure ratio and pressure drop. CFD results show good agreement with industrial operational data, validating the simulation approach. Key findings indicate that increasing the throat diameter elevates the back pressure ratio, potentially nearing its critical limit, while an optimal diffuser length minimizes pressure loss effectively. These insights provide essential theoretical foundations and practical references for the optimized design of CFVNs in ethylene cracking furnaces, balancing distribution uniformity with energy efficiency.

In response to the serious damage to the internal components and body of coke burning drum in the 1.1 Mt/a ethylene plant of a petrochemical company as well as the decrease in the settling and separation effect of coke particles, the existing equipment has been renovated. Drawing on the micro cyclone separation technology, this article analyzes the working principle of rotary jet separator. The internal flow field of the rotary jet separator is analyzed through CFD simulation, obtaining the internal flow field of the rotary jet separator and the microscopic liquid phase jet fragmentation and atomization. The dust removal efficiency and particle trajectory of the rotary jet separator under different conditions are compared using a DPM model, and the dust removal efficiency is analyzed. The research results indicate that rotary jet separator has good application prospects in the coke burning drum of ethylene plant.

Propylene refrigeration compressor is one of the critical equipment in ethylene plant and is driven by steam turbine. To solve the problem of sudden change in the axial position of propylene refrigeration compressor, this article uses the condition monitoring software to determine through the analysis of gap voltage trend and condition monitoring map that the root cause of the sudden change is the malfunction of fire sprinkler system of the compressor, which led to the deformation of bearing housing. The influence of the design defects of the fire sprinkler system on the stable operation of compressor unit is eliminated by upgrading the deluge valve structure and optimizing the spray nozzle layout.

In the 220 kt/a ethylene plant of a petrochemical company, there was a hidden danger of steam leakage from the high-pressure side of propylene refrigeration compressor turbine directly discharged into the atmosphere. In order to minimize the direct discharge of steam leakage into the atmosphere and control the vacuum degree of the turbine within design specifications, a leakage steam condenser was added. Zero leakage in the propylene refrigeration compressor turbine was achieved, and a safe, stable, long-term, full-load and optimum operation of the ethylene plant was ensured. 

This article systematically reviews the unplanned shutdown cases in ethylene plants in China from 1982 to 2023, focusing on a statistical analysis of 31 leakage-related events. Combined with typical cases of leakage that did not result in unplanned shutdown, key vulnerable points prone to leakage are identified, including hydrogen service locations, low-temperature flanges, and areas subject to two-phase flow erosion.? More targeted key protective measures are formulated for different risk characteristics, providing scientific and specific reference for leakage prevention and control management in ethylene plants.