Based on the conversion and retrofitting project of a certain ethylene oxide/ ethylene glycol (EO/EG) unit, over 80% of the reactor's ethylene oxide equivalent (EOE) capacity was utilized to produce purified ethylene oxide (PEO) for the first time by adding an EO purification system operated in series, thereby converting ethylene glycol production to ethylene oxide production. The new EO purification tower employs novel composite sieve plates to meet the capacity expansion requirements. An optimized heating control system was used to accommodate broader feed compositions, while an integrated aldehyde removal system was developed to control the aldehyde content in the product of the new EO purification tower.

The Dow Chemical Fire and Explosion Index method was applied to study the consequences of fire and explosion accidents in ethylene storage tanks at a company in Nantong. The results indicate that the fire and explosion risk consequences of the ethylene storage tanks were severe, with an exposure radius of 49.15 m and an exposure area of 7 585.37 m2 before implementing safety compensation measures. After implementing targeted process controls, material isolation and fire prevention measures, the post-safety compensation consequences of fire and explosion accidents were reduced to a lower risk level, with an exposure radius of 20.64 m and an exposure area of 1 337.67 m2. These results demonstrate that safety compensation measures can effectively reduce the severity of risks and the impact scope of fire and explosion accidents in ethylene storage tanks. However, during actual operations, the exposure radius and hazardous coverage area still exceeded the protective range of the tank dike system. Therefore, additional measures are required to further reduce safety risks. 

Intergraph's Smart Plant P&ID (SPP&ID) is taken as the research subject. Through an analysis of the software's functionalities and validation through engineering practice, this paper focuses on introducing SPP&ID's core technical advantages, such as ensuring design data consistency through rule validation mechanisms, and systematically explores its integrated design capabilities and potential for secondary development. Current research has indicated that engineering designers can enhance the efficiency and quality of intelligent design work by optimizing the automatic export process for piping schedule and adding an automatic calculation module for insulation thickness through secondary development of SPP&ID. This research further validates the core value of intelligent tools in digital collaborative design.

Coil system is the core component of a tubular heating furnace, and bends are critical connecting elements within it. This paper uses Fluent to study the flow resistance characteristics of sharp bends and reducing bends in vacuum furnaces to obtain the velocity distribution, pressure distribution and streamline pattern along the flow path and at each cross-section inside the bends, and summarizes the influence laws of vaporization rate, inlet flow velocity, diameter ratio and bend diameter ratio on pressure drop. Results show that sharp bends outperform reducing bends in terms of pressure drop. The flow inside the bends presents characteristics of helical flow, double-vortex secondary flow, and even four-vortex secondary flow. The flow inside the bends has a significant influence on the downstream affected area, and the pressure drop of the bends shows a parabolic variation trend with the increase of vaporization rate and flow velocity. 

Taking the start-up and shutdown processes of the 220 t/a ethylene plant of a petrochemical company for overhaul in 2024 as the research object, this paper systematically analyzes the application effect of technical measures for start-up and shutdown. Through optimization measures such as discharging materials from each cracking furnace one by one, reheating the cryogenic separation zone, and putting the shut-down material recovery line into operation, all suitable materials have been recovered, and the emission reduction control of the ethylene plant has reached the best level in history. It has effectively reduced the material loss during start-up and shutdown, and improved the energy utilization efficiency. Meanwhile, this paper conducts a systematic analysis of the equipment problems and operational deficiencies exposed during the start-up and shutdown, and puts forward some improvement suggestions.

At present, the newly built ethylene plants in China show an increasingly prominent trend of large-scale development. The design capacity of single-set ethylene plants generally exceeds 1.2 Mt/a, and ultra-large ethylene plants with a capacity of 1.5 Mt/a and above have gradually become the mainstream configuration in the industry. As a core high-energy-consumption equipment of ethylene plants, cracking gas compressor can effectively reduce the carbon emissions of ethylene plants by replacing the traditional steam turbine drive with electric motor drive. Taking the cracking gas compressor of a 1.6 Mt/a ethylene plant as the research object, this paper analyzes the impacts of compressor electrification on equipment and piping layout, and summarizes a complete set of layout design schemes. The research results can provide a sound engineering reference for the electrification renovation of cracking gas compressors in ethylene plants of the same scale, and promote the popularization of electrification and high-quality low-carbon development of the refining and chemical industry.

This paper introduces and analyzes the decrease of interstage outlet temperature, the abnormal operation of caustic washing and spent caustic treatment unit, the fluctuation of process parameters during washing oil injection, and other abnormal phenomenon caused by the insufficient separation efficiency and liquid entrainment of demister in the interstage tanks of cracking gas compressor during the full-load operation of the 1.1 Mt/a ethylene plant of a company. Through design modification, the demister in the interstage tanks was completely replaced during the major overhaul in 2024, and the operation of the cracking gas compressor system before and after the replacement of demister was compared. The results show that the upgraded demister can meet the full-load operation requirements of the ethylene plant, and all the abnormal situations existing before the modification have been resolved. 

This study investigates the leakage problems of forged aluminum shaft seals in cracking gas compressors under alkaline conditions (pH=10.5). Through chemical corrosion kinetics analysis and engineering practices, the corrosion-thermomechanical coupling failure mechanism was elucidated. Results indicate that the corrosion rate of aluminum in alkaline environments reaches 0.25 mm/month, while the thermal expansion coefficient mismatch between forged aluminum (2.4×10^-5/℃) and steel shaft (1.2×10^-5/℃) causes a fluctuation rate exceeding 30% in labyrinth clearance, leading to seal performance degradation. Polyetheretherketone (PEEK) was proposed to replace forged aluminum. Its superior corrosion resistance (<0.01 mm/a), low friction coefficient (0.2), and excellent thermal compatibility (2.2×10^-5/℃) can significantly enhance sealing reliability. Field applications confirmed that PEEK shaft seals reduce leakage rates by 98%, decrease annual maintenance costs by 82.4%, extend service life from 8 months to no less than 5 years, and eliminate unplanned downtime, providing practical basis for the optimization of industrial sealing systems.

Based on a 1 400 kt/a ethylene complex and 13 typical ethylene feedstocks, an ethylene complex model was developed using SPYRO cracking furnace simulation software and Petro-Sim process simulation software. This modeling yielded comprehensive product yield data for various ethylene feedstocks. By integrating actual production data and industry experience, the processing cost per ton of different ethylene feedstocks was determined, and a benefit evaluation model for different ethylene feedstocks was established. This evaluation model enables enterprises to quickly complete the benefit evaluation, optimization and ranking of ethylene feedstocks based on market dynamics, and provides a scientific basis for enterprises' production and operation decision-making.

This study analyzes the causes of leakage in the convection section coils of cracking furnaces in domestic ethylene plants. It is concluded that combined factors including thermal stress, internal medium effects, high-temperature oxidation corrosion, and flue gas dew point corrosion are the primary causes of the perforation leakage and cracking in convection section coils. Preventive measures to mitigate coil corrosion are also proposed. 

Four tests, including isothermal carburizing, high-temperature cyclic oxidation, simulated coking, and welding joint performance testing, were conducted to demonstrate the advantages of 30Cr45NiAl furnace tubes over ordinary nickel chromium alloy furnace tubes. The results show that the anti carburizing ability of 30Cr45NiAl furnace tubes at 1 000~1 100 ℃ is more than 40％ higher than that of ordinary furnace tubes. Its oxidation resistance and anti coking performance are also significantly ahead of ordinary furnace tubes. Welding with welding materials produced on a large scale in the market can also obtain joints with good mechanical properties. Finally, the prospects for the use of aluminum containing furnace tubes were discussed, and the factors that currently restricting their large-scale use were analyzed.

This paper elaborates on the process flow of the fuel gas system in a 220 kt/a ethylene plant of a petrochemical company. Variations in the composition and flow rate of VOCs tail gas from the atmospheric tank farm cause fluctuations in the pressure of fuel gas network, which in turn leads to the instability in the coil outlet temperature (COT) of cracking furnace and the discharge of surplus fuel gas to flare. Based on the existing process flow, the surplus fuel gas is sent to the olefin unit or integrated into the fuel gas system after being pressurized by a compressor. The delivery valve is a gate valve, which requires manual operation by operators on site. It is difficult to make timely on-site adjustments, resulting in the situation that the fuel gas is frequently flared to control the pressure of fuel gas system. Through operational optimization and technical modification, the problems of black smoke emission from cracking furnace and pressure fluctuations in fuel gas network have been solved.