Under the strategic framework of "reducing oil output while increasing chemical production," the refining and petrochemical industry is progressively shifting toward high-end new-material manufacturing. This transition generates highly viscous polymer melts which give rise to thick thermal boundary layers and a high tendency for wall fouling, thereby posing severe challenges to conventional heat-transfer technologies. As an active heat transfer enhancement technique, ultrasonic heat transfer enhancement intensifies heat transfer via acoustic cavitation and acoustic streaming effects. This paper presents a systematic review of the underlying mechanisms of ultrasonic-enhanced heat transfer, along with recent experimental and numerical advances in double-pipe, coiled-tube, shell-and-tube, plate and microchannel heat exchangers. Meanwhile, to address the energy-efficiency bottleneck of standalone ultrasonic enhancement, the electro-thermal coupling concept is introduced. A strategy for comprehensively trading off ultrasonic power consumption against system-level benefits including heat transfer improvement, pump power saving and extended operating cycle is proposed. On this basis, critical issues such as equipment scale-up and industrial reliability are discussed, which can serve as a reference for developing process packages of ultrasonic heat transfer enhancement.

As refining, petrochemical, coal-chemical and other facilities continue to develop toward large-scale capacity, tower vessels, their core process equipment, are also trending toward larger size and heavier weight. This trend poses significant challenges for tower design, manufacturing, transportation, lifting, and internal component installation, further underscoring the critical need and significance for lightweight design in large-scale tower vessels. This paper focuses on the key objectives of lightweight design for large-scale tower vessels. Based on extensive engineering practice data, research is carried out from three dimensions: optimization of tower structure, selection of high-performance materials and application of appropriate design methods. It is concluded that the adoption of high-efficiency tower internals, high-strength materials and refined design methods can significantly reduce the overall mass of towers and effectively overcome engineering challenges such as manufacturing, transportation, and hoisting arising from excessive vessel weight. Meanwhile, corresponding strategies are proposed for the lightweight design of large-scale towers, which are of great significance for improving the economic efficiency and market competitiveness of plants, breaking through bottlenecks in the engineering capacity of large-scale equipment, shortening project construction cycles, enhancing HSE standards and promoting the achievement of low-carbon emission reduction targets.

Hydrogenation reactors serve as core equipment in refining and chemical enterprises, and the installation quality of their large-scale internals directly affects production safety and economic benefits. To address problems including monotonous conventional installation training modes and non-standard personnel operations, a research and development center adopts the jointly-developed internals technology of LYHC-Ⅲ hydrogenation reactors with relevant design institutes as the core. It builds a digital display system for internals of LYHC-series hydrogenation reactors by means of 3DS MAX modeling, VRay rendering and Unity3D software development. The system realizes three-dimensional dynamic visualization of installation procedures for each internal component. This system has been applied in a newly-built 2.6 Mt/a hydrocracking unit project of a large-scale refining-chemical enterprise. It cuts the training cycle by 50% and shortens the construction period by 20%, giving full play to the performance advantages of the LYHC-Ⅲ hydrogenation reactor internals technology. Meanwhile, with the adoption of this system, the radial temperature difference at each bed inlet of the two 5.4 m-diameter large hydrogenation reactors in the unit can be kept below 3.0 ℃.

During periodic operation, the coke drum is repeatedly subjected to alternating heating and cooling cycles. Influenced by the characteristics of the feed inlet structure, poor uniformity of material distribution in the feed inlet region can induce significant thermal stress in the drum shell. Under the long-term action of such thermal stress, structural damage such as shell cracking and deformation is prone to occur, directly threatening the operational safety of the equipment. To address this issue, this paper investigates the material distribution patterns and wall temperature field distribution characteristics within the coke drum shell under three common feed inlet structural schemes. The study reveals the influence mechanisms of feed inlet structure differences on the structural stability and service life of the coke drum, which can provide theoretical support for subsequent optimization design.

This paper carries out relevant modifications for the large-scale imported compressor interstage cooler aiming at existing problems including damage and shedding of corrugated fins on the windward side of the hot-air passage, gap corrosion and blockage of corrugated fins, severe corrosion and leakage of tube bundles, significant bending deformation during integral hoisting, frequent fracture of tie rods between upper and lower side plates, as well as low heat-exchange efficiency. Modification measures are implemented as follows: installing perforated-plate anti-erosion baffles on the air-inlet side of the cooler; adding mist eliminators on the cold-air side; replacing the material of heat-exchange fins from aluminum alloy to red copper; changing the original 4 mm-thick downward-bent steel plates for upper and lower side plates to 12 mm-thick upward-bent steel plates, increasing the thickness of carbon-steel reinforcing plates in the middle of tube bundles from 2 mm to 4 mm, connecting the reinforcing plate assemblies to upper and lower side plates via bolts while removing the connecting screw rods between the original upper and lower side plates; retrofitting the roller structure of side bottom plates; installing automatic drain traps; installing low-potential zinc blocks to inhibit corrosion of copper alloys based on the principle of sacrificial-anode cathodic protection; and adjusting circulating water quality. Through this series of improvements, the problems existing in the compressor interstage cooler have been eliminated. The above-mentioned measures can provide references for fault treatment and energy-saving retrofitting of coolers of similar centrifugal air compressors.

The HRCS domestic stepless capacity control system has been applied to a catalytic dry gas compressor and a coking dry gas compressor, enabling stepless regulation of discharge capacity within the range of 0~100%. During actual operation, the regulation range is maintained between 30% and 100%. However, when the compressor units operate at loads below 50%, suction valve internal leakage tends to occur, resulting in elevated suction and discharge temperatures, frequent valve failures and significant increase in equipment maintenance frequency. By modifying the control curve of the stepless capacity control system, the control point is adjusted from 30% to 50%. That is, the trigger condition for opening the unit recycle line is changed from a load below 30% to a load below 50%. This measure can effectively reduce the gas-valve failure rate, extend the service life of gas valves, and lower the frequency and cost of equipment maintenance. Meanwhile, countermeasures including tapping tests before startup and gas-bag pressurization are proposed to address sticking of the electro-hydraulic converter and oil-pressure interlock faults. After implementing the above improvements, when Compressor A is put into service for the catalytic dry gas compressor and coking dry gas compressor, the annual electricity cost savings reach approximately 977 000 CNY and 3 688 000 CNY respectively, achieving the goals of energy conservation, power reduction, cost control and efficiency improvement.

During the operation of a 1.5 million tons/year residue hydrotreating unit in a refinery, corrosion leakage occurred in the tee of the high-pressure air cooler inlet of the secondary reaction product, which seriously affected the long-term safe and stable operation of the unit. Analysis indicates that the primary cause of corrosion is insufficient water injection, which results in excessively high concentrations of ammonium hydrosulfide and chloride ions in the reactor effluent system. This condition readily induces ammonium chloride crystallization and deposition, subsequently leading to erosion-corrosion caused by ammonium chloride solutions. Meanwhile, the abrupt changes in flow velocity and flow pattern at locations such as elbows and tees further accelerate the corrosion process. By adjusting the water injection scheme and upgrading the materials, the corrosion rate at susceptible locations has been significantly reduced, while the corrosion of the piping between the first-stage and second-stage high-pressure air coolers has also been effectively mitigated. In addition, the paper proposes several protective measures to address the corrosion issues in the residue hydrotreating unit including strengthening feedstock management, adjusting the water injection scheme, upgrading materials in critical areas, and enhancing corrosion monitoring and inspection.

During the operation of a 200 kt/a acetonitrile-based butadiene extraction unit, the reboilers in the extraction system frequently experienced tube bundle corrosion and leakage, which has seriously threatened the safe production of the unit. It was found through analysis that the corrosion mechanism involved the stepwise hydrolysis of hydrated acetonitrile under high-temperature conditions, generating acetamide, acetic acid and ammonia gas. The generated acetic acid may cause uniform corrosion and pitting on carbon steel equipment. Meanwhile, iron ions generated by corrosion possessed strong catalytic activity, accelerating the polymerization of butadiene and alkynes to form gums and deposits. The adhesion of deposits reduced the heat-transfer efficiency of the reboilers and caused a passive rise in the column bottom temperature, which further aggravated acetonitrile hydrolysis. Consequently, a vicious cycle of hydrolysis-corrosion-polymerization-enhanced hydrolysis was formed. The insufficient regeneration capacity of the original acetonitrile recovery column design resulted in low purity and excessive water content in the circulating solvent. Continuous accumulation of impurities, moisture and catalytic media in the circulating solvent created favorable conditions for acetonitrile hydrolysis, which constituted the root cause of the corrosion. Accordingly, modifications were carried out on the trays, cold source and supporting instrument valves of the acetonitrile recovery column. The solvent regeneration rate was increased from 1 t/h to 3 t/h, and supporting process control measures including temperature control, water content control, deoxygenation and passivation were implemented. After modification, the quality of circulating acetonitrile was significantly improved. Equipment corrosion and polymer formation were effectively restrained. Meanwhile, acetonitrile loss and steam consumption were greatly reduced, bringing remarkable annual economic benefits. This case can provide engineering references for anti-corrosion and solvent-system optimization of similar acetonitrile-based butadiene extraction units.

In the butyl octanol production industry, the oxo synthesis agitator has long been plagued by vibration problems, which can easily lead to mechanical seal leakage, accelerated wear of the bottom bearing, and bending or even fracture of the agitator shaft. Investigations have shown that the service life of the mechanical seal and bottom bearing in such agitated vessels differ considerably, typically ranging from 1 to 5 years. According to the structural configuration of the gearbox, the agitator can be mainly classified into two types: vertical connection with spur gears and horizontal connection with bevel gears. Due to the long length of the agitator shaft, its straightness cannot be precisely controlled, and the resulting whipping often leads to overall vibration of the reactor frame, thereby affecting operational stability. Based on actual engineering case, this paper effectively addresses the vibration issues of large agitators by analyzing the causes and implementing corresponding measures, thereby ensuring the long-term safe and stable operation of the unit.

Petrochemical plants operate under complex working conditions, which impose high demands on equipment management. While ERP systems help petrochemical enterprises improve their operational management, they also increase the workload of maintaining ERP attribute data. In general, after the commissioning of a medium-scale petrochemical plant, it takes nearly 20 person-months for a single operation-maintenance staff to input and maintain EM (Equipment Lifecycle Management) data. A large-scale integrated refining-chemical complex project typically consists of 15 medium-sized process units, and the initialization of EM data after project commissioning is extremely labor-intensive. This paper presents an automatic attribute filling mechanism for ERP-EM of petrochemical plant equipment based on data governance. The mechanism collects static equipment information through digital delivery and performs data governance on structured data, after which an interface is established between the digital delivery platform and the ERP system to accomplish automatic attribute entry. Adoption of this mechanism can greatly improve work efficiency and information accuracy.

During the execution of petrochemical engineering EPC turnkey projects, inadequate management of equipment preservation can lead to increased costs for the general contractor or construction units, adversely impact the project schedule and even affect the final fulfillment of the contract as scheduled. Therefore, equipment preservation has received increasing attention during project execution. This paper elaborates on the key links, management essentials and corresponding suggestions for equipment preservation in petrochemical engineering EPC turnkey projects, offering valuable insights for equipment preservation in petrochemical engineering construction.

LNG carriers are internationally-recognized ship types featuring high-technology content, high-manufacturing difficulty and high added value, and they are playing an increasingly important role in the global energy market. To accurately grasp the research progress and frontier hotspots of China's high-end LNG ship sector and deeply analyze its development trends, relevant literature published from 2009 to 2024 was retrieved from the CNKI academic journal database with LNG, liquefied natural gas and ship as subject terms. Using the bibliometric tool CiteSpace, visual bibliometric analysis was conducted on 1315 cleaned literature samples from four perspectives: publication output, core authors, research institutions and key words. The study reveals that the overall number of Chinese research papers concerning LNG ships has shown an upward trend since 2009. Research teams have formed relatively mature cooperative relationships, and close collaborations exist among different institutions in geographically adjacent regions. Major research hotspots focus on fields such as cargo tank structural strength and dual-fuel power systems, while LNG bunkering vessels, hybrid propulsion systems, operational risk assessment and ship-wide energy efficiency management may represent future cutting-edge research directions.

In tank defect inspection, achieving automated detection holds significant practical importance. Currently, tank bottom plate inspections often require tank opening and cleaning followed by manual operations, which are labor-intensive and expose workers to hazardous internal environments that pose serious health risks. This study designed and developed a self-propelled inspection robot based on remote field eddy current (RFEC) detection technology that overcome interference from non-ferromagnetic impurities on tank bottom, thus achieving automated inspection of tank bottom plate. Simultaneously, to address insufficient data accuracy in remote field eddy current (RFEC) detection of tank bottom plate, an intelligent defect recognition model based on Gradient Boosting Decision Tree (GBDT) was constructed. The model forms a training dataset containing dimensions such as defect size and eddy current phase shift by utilizing geometric parameters of tank bottom plate defects (length, width, depth) and corresponding signal features from Remote Field Eddy Current (RFEC) sensor arrays. This enables the inversion of defect morphological characteristics using RFEC signals. This inspection technology provides an efficient and precise unmanned solution for petrochemical storage tank bottom plates, yielding substantial engineering merits in safeguarding industrial storage and transportation safety.