The relief rate of liquefied hydrocarbon spherical tanks for mixed components under external fire scenarios depends not only on the heat absorbed, but also on the relief time. Using static calculation methods to calculate the relief rate, the results tend to be conservative. In this research, a dynamic safety relief model of liquefied hydrocarbon spherical tank groups was constructed to calculate the safety relief load of liquefied hydrocarbon spherical tank groups under external fire scenarios. DYNSIM, a dynamic simulation software, was used to simulate the impact of external fire on the relief of liquefied hydrocarbon spherical tanks and tank groups with different compositions and volumes. The simulation results show that during the relief, the relief rate, relief temperature and molecular weight of relief medium vary with the relief time. Compared to static calculation methods, dynamic simulation considers the time factor, and the calculation results are more aligned with the actual relief conditions. Using dynamic simulation methods to calculate the relief parameters of spherical tank groups can reasonably optimize the relief network, providing guidance for the design of safety valves and flare systems.

GB/T4732 Pressure Vessels Design by Analysis has introduced the new methods for buckling analysis and evaluation in ASME Ⅷ-2-2021. The correct understanding of the new methods will be helpful for their rational use in engineering design in the future. Based on the theoretical principles of buckling, this paper takes typical combined structures in pressure vessels as an example, and carries out finite element numerical calculations using two buckling analysis methods based on elastic and elastic-plastic pre-stress. After comparative analysis, some conclusions were obtained for reference and further discussion. It is reasonable to calculate the buckling load with the first-order buckling mode and determine the allowable load accordingly in buckling analysis. For structures in elastic buckling state, the buckling load values calculated by elastic and elastic-plastic pre-stress analysis are almost the same. In practical engineering applications, elastic pre-stress buckling analysis can be directly used to reduce the calculation workload and improve the calculation efficiency, and the final allowable load value has a greater safety margin than that determined by elastic-plastic pre-stress buckling analysis.

Considering factors such as the management, heat dissipation and fire safety of centralized cable laying, cable interlayers are installed in the design of substations in petrochemical plants. Cables laid in cable interlayers generate heat when they are energized. Over high internal temperature of cable interlayers will cause damage to the insulation of the cables and related equipment. To obtain a more accurate calculation of the heat loss generated by the cables in cable interlayers and avoid the increase in cost caused by adding a large number of HVAC loads in cable interlayers, multiple methods are adopted in the design to calculate the heat loss of the cable interlayers, providing a basis for the calculation of heat generation in the cable interlayers of substations. This paper, taking a substation in a petrochemical plant project as an actual case, proposes a calculation formula for the heat generation in cable interlayers, aiming to ensure the safe operation of equipment while achieving energy conservation and environmental protection.

The emergency discharge system for combustible gas is an important component of safety facilities in petrochemical plants, and the correct calculation of pressure drop is a prerequisite for the rational design of the discharge system. To address the issue of pressure drop calculation method, this paper compares the calculation formulas adopted in SH 3009-2013 and API 521-2014, proves through theoretical derivation that the calculation formula for Mach number in SH 3009-2013 is incorrect, and further analyzes the impact of the incorrect calculation formula on the design of emergency discharge system for combustible gas. It is suggested that the calculation formula for Mach number is to be corrected during the revision of SH 3009-2013.

The separation process of acetonitrile-isopropanol binary azeotropic system was simulated by Aspen Plus simulation software, and ethylene glycol was selected as the best extractant. The separation process for recovering acetonitrile and isopropanol by ethylene glycol extractive distillation was optimized and analyzed, and the optimal operating parameters of the extractive distillation process were determined as follows: the extractive distillation process is operated under negative pressure, the optimum number of theoretical plates in the extraction column is 20, with the raw material and extractant fed into the 7th and 18th stages, respectively, the solvent ratio is 1.2, the reflux ratio is 1, the optimum number of theoretical plates in the recovery column is 7, the optimum number of feed stage is 4, and the reflux ratio is 0.35. After optimization, the mass fractions of acetonitrile and isopropanol are 99.25% and 99.39%, respectively. The reboiler duty requirements of the extraction column and the recovery column are 473.01 kW and 493.25 kW, respectively, and the condenser duty requirements of the extraction column and the recovery column are 395.11 kW and 298.22 kW, respectively. High purity acetonitrile and isopropanol products can be obtained by extractive distillation using ethylene glycol as the extractant. The ethylene glycol recovered can be recycled to the extractive distillation process.

The application and achievements of the seven principles and seven themes of PRINCE2 in construction management of joint venture mode of EPC for petrochemical projects are discussed, taking the construction management of an ethylene plant as an example. This will provide reference for similar projects to clarify the responsibilities of stakeholders, highlight management priorities and fully leverage the advantages of stakeholders.

This paper takes the design of steel structures in the radiation section of cracking furnace as an example, and introduces how to use Tekla Structures software to complete the detailed design drawings of the cracking furnace. During engineering design, the goal of linking the well-developed 3D model with 2D drawings and quickly and efficiently converting the 3D model into 2D drawings were achieved, simplifying the traditional 2D drawing mode and assisting in the prefabrication of cracking furnace steel structures in cracking furnace manufacturing plants and the smooth installation on project sites.

With the strong advocacy and promotion of sponge cities by the government, industrial plants, as an important part of a city, should actively explore the application of sponge concept in the plants. With large footprint and high water consumption, refineries and petrochemical plants are typical objects that urgently need to apply the sponge concept. This article compares the differences between the design concept of rainwater pipe network in traditional refineries and petrochemical plants and the sponge concept. Based on the relevant characteristics of various underlying surfaces in refineries and petrochemical plants, the units and blocks in the plant area are classified, and the feasibility of sponge transformation is analyzed for each category. Taking an under-construction rainwater pipe network in a refinery in a coastal province in southern China as the example, corresponding sponge facilities are installed based on the comprehensive analysis of its underlying surface conditions, and SWMM software is used to simulate the drainage effect after sponge transformation. The simulation results show that the installation of sponge facilities in the plant area can effectively reduce rainwater runoff, reduce the pipe diameter of rainwater pipe network, and reduce the construction investment of rainwater pipe network.

The feasibility of producing 5# industrial white oil in a VGO hydrocracking unit was analyzed. The process was simulated by Aspen Plus. The viscosity and flash point of diesel product could be optimized by adjusting the operating parameters of the fractionation system without modifying the reaction section, and the product properties could meet the standard of 5# industrial white oil (I). It further improved the economic benefit of the unit, widened the range of product and improved the comprehensive competitiveness of the refinery.

The generation of polymers in butadiene plants is an inevitable challenge in operation. This paper proposes an optimization method to solve the problem of excessive polymers in the circulating solvent of butadiene plants, and proposes a corresponding anti-polymerization scheme for the blockage of reboiler during butadiene production and the expansion and cracking of the gland of reboiler outlet valve due to polymer aggregation. Firstly, the injection points of auxiliary polymerization inhibitor are repositioned to ensure a more uniform distribution of the auxiliary polymerization inhibitor in the circulating acetonitrile solvent, thus achieving the purpose of polymerization inhibition. Secondly, technical transformation is carried out for the valve form of the system by installing flow lines at the valve gland to reduce the dead zone, thus achieving the purposes of reducing polymer generation and ensuring long-term, safe and stable operation of butadiene plants.

In response to the ammonia recovery difficulties in ammonia refrigeration system in the recontacting section of continuous catalytic reforming units, this study proposes two new ammonia-free refrigeration processes, i.e., the recontacting absorber combined with lithium bromide refrigeration and the direct application of low-temperature lithium bromide refrigeration. The energy consumption, CO? emissions, investment and technical-economic performance of the two new processes were evaluated. The results show that, compared to the conventional process, both the two new processes can maintain the hydrogen purity after the recontacting while effectively utilizing the low-temperature waste heat from the unit. The electricity consumption and energy consumption of the unit can be reduced by around 40% and 2%, respectively. Remarkable saving energy and carbon reduction effect can be achieved. The static investment of project can be recovered in 1 to 3 years, indicating significant economic benefits.

Cracking and leakage of heat exchange tubes occurred during the operation of a spiral wound heat exchanger of a company. By means of macroscopic observation, chemical composition analysis, hardness test, metallographic and fracture analysis, the reasons for the cracking of TP304 heat exchange tubes were analyzed. The results showed that chloride stress corrosion cracking occurred in the heat exchange tubes. The shell side medium contained a certain amount of Cl-, which led to the rupture of passivation film on the surface of heat exchange tubes and the formation of corrosion pits. With the enrichment and concentration of Cl- in the corrosion pits, stress corrosion cracks began to initiate under the action of machining residual stress. With the passage of time, the cracks continued to expand, resulting in leakage through the heat exchange tubes.

 In large-scale PTA plants, the oxidation unit is usually designed as two parallel production lines due to the manufacturing limitation of equipment. Based on the PTA plant with the largest single production capacity of 3 million tons/year in the world, this paper introduces the design scheme of two oxidation reaction units and one crystallization unit, focusing on the equipment layout, the coupling design of equipment and structure, the nozzle layout of the slurry equipment and the design of key pipelines.

Taking engineering companies as the research object, this paper systematically expounds the construction logic, implementation pathways, and evaluation and improvement mechanisms of compliance management systems based on compliance management challenges faced by the companies according to ISO 37301 Compliance Management Systems - Requirements with Guidelines for use and the Rules for the Compliance Management of Central Enterprises. Compliance management requirements are integrated into the whole process management of projects by leveraging the characteristics of engineering construction enterprises,  providing theoretical and practical references for the construction of compliance management systems for engineering construction enterprises and helping them enhance their compliance governance capabilities.

This article introduces the definitions of digital design and full-element digital delivery, and analyzes the relationship between them. The four basic characteristics of digital design and the significance of modelling the full-element digital delivery are discussed. Their applications are analyzed from the aspects of engineering construction, production preparation, and operation and maintenance.