Taking the product upgrading and ethylene revamping project of an old inland petrochemical enterprise as an example, this paper analyzes the internal and external environmental factors influencing the project execution, makes researches from the aspects of large equipment transportation, out-of-gauge equipment classification, winter construction, key route of ethylene construction, construction problems in old plant area and safety risks, identifies the risks in project execution and gives some suggestions and measures.

The problems in the styrene extraction unit at SINOPEC-SK (Wuhan) Petrochemical Company Limited and the improvement measures are introduced. Serious blockage of packing below the feed nozzle of styrene refining tower occurred only 2.5 months after the first startup of the unit. The reasons for the short operation period of the refining tower were analyzed combined with various data of the actual operation, and the main shortcomings of organic acid decoloring process were summarized. In order to overcome the disadvantage of easy polymerization of maleic anhydride with styrene, some attempts were made, such as lowering the concentration of maleic anhydride, lowering the operating temperature, replacing the pure maleic anhydride with a new decolorant and modifying the equipment. The comparison of the actual operation results before and after the implementation showed that several improvement attempts have achieved certain results.

Whether a bid-winning notification issued has the legal effect of concluding a contract has long been debated, and there is no final conclusion at present. To judge whether a contract is concluded after the bid-winning notification is issued, specific analysis shall be made according to the contents of the contract and the actions taken by both parties. Only when the contents of the bid-winning notification meet the acceptance conditions stipulated in the Civil Code of the People’s Republic of China and the successful bidder has started work in accordance with the requirements of the bid-winning notification, an acceptance is constituted and the contract is concluded.

Three months after the cracking furnace of 800 kt/a steam cracking unit was built and put into operation, the furnace lining was inspected after the furnace was shut down for coke burning. It was found that the surface layer of some lining refractory bricks above the coke burning mouth of the furnace was cracked and peeled, which was purple red. Based on the analysis of the whole components of the peeled refractory brick, it is found that the abnormal components are added into the refractory brick. The source of the abnormal components is found from the process flow, and the countermeasures are put forward.

The ethylene plant at PetroChina Fushun Petrochemical Company resumed operation after 5 years of shutdown. The heat transfer effect of heat exchanger gradually decreased and the water quality of circulating water became worse, affecting the stable operation of the plant at high load. Based on analysis and research, some corresponding measures were taken to improve the water quality of circulating water. During the overhaul in 2021, the impurities in heat exchanger and circulating water pipeline were thoroughly removed, and the circulating water system was revamped to solve the bottleneck problem, thus achieving the stable and up-to-standard quality of circulating water and promoting the long-term operation of the plant at high load.

Butadiene is flammable, explosive and highly hazardous, and is easy to polymerize when stored at high temperature. Therefore, it is particularly important to maintain the storage of butadiene at low temperature to prevent its polymerization. In order to maintain the low-temperature storage of butadiene and reduce its cold loss, the storage tank usually adopts cold insulation method. The heat absorption calculation of storage tank should not only consider the convective heat transfer with the natural environment, but also the solar radiation heat transfer and the radiation heat transfer in the natural environment. The construction methods for cold insulation layer and external protective layer of spherical tank are not specified in the current specifications. This paper discusses the cold insulation design and heat absorption calculation of storage tank, analyzes the heat absorption calculation of storage tank through examples, and puts forward some methods for reference for the construction of cold insulation layer and protective layer of spherical tank.

Since the modification and capacity expansion of the ethylene cracker at Sinopec Guangzhou Company in 2003, the process water system was seriously blocked. After adding new coalescers and heat exchangers and adopting toluene extraction technology, the blockage problem in process water system was successfully solved, and the stable operation of process water system throughout one overhaul cycle, i.e. 4 to 5 years, can be guaranteed, thus eliminating the risk of unit shutdown due to the blockage in process water system,  laying a foundation for the long-term operation of the unit, and reducing the maintenance cost of process water system in one overhaul cycle by more than 600,000 yuan.

The spent caustic oxidation unit of ethylene plant plays an important role in environmental protection. The unsaturated sulfide including Na₂S in the spent caustic solution is mainly saturated by oxidation. Before entering the oxidation section, a stripper is generally designed to remove hydrocarbons such as the polymer of carbonyls and dienes carried in the spent caustic solution. This part of hydrocarbons is easy to polymerize at high temperature and block the stripper, affecting the smooth operation of the plant. After the stripper is blocked, it is often repaired by means of hydraulic cleaning, which produces a large amount of hazardous wastes including the polymer of carbonyls and dienes. The wastes are difficult to treat, the operating environment is harsh and the safety and environmental protection risks are high. By establishing the process of wash oil soaking and circulating cleaning in the stripper, the above-mentioned problems can be effectively solved after the project is put into operation smoothly.

Taking a HDPE plant using kettle type slurry process as the example, this paper introduces the process flow of polymerization section and the equipment arrangement of reaction structure, analyzes the process characteristics and key points of piping arrangement of raw material system, slurry system and jacket water system, and focuses on the optimization of piping design for slurry system. By summarizing the design experiences of similar plants, the future optimization of reaction structure is proposed.

Traceability analysis was carried out on the equipment damage caused by the unreasonable structure and the unsuitable sealing form of the filter with electric scraping brush in the quench oil system of ethylene plant. Through the in-depth analysis of the problems occurred in the past, a technical transformation plan was proposed combined with the mechanical principle, and the plan was implemented and verified. The problems in this type of filter such as damaged electric scraping brush and frequent leakage of mechanical seal were successfully solved, providing guarantee for the long-term, safe and stable operation of the ethylene plant.

A 150 kt/a ethylene plant resumed operation after 3 years of shutdown, and heat excursions and abnormal changes in material composition occurred in the quench water system. This article gradually identifies the causes of the abnormalities based on the parameter changes of each tower of the quench system and the analysis of material composition, takes the quench water emulsification phenomenon as an example to analyze in detail the quench water emulsification mechanism, and discusses the harm of quench water emulsification to the entire system as well as the corresponding measures and preventive measures taken.

The blockage of quench oil / dilution steam generator includes the polymer blockage of heat exchanger shell and the polymer blockage in process water pipeline of heat exchanger. This paper introduces the innovative treatment method for the blockage of quench oil / dilution steam generator in the SINOPEC-SK ethylene plant, discusses in detail the operation steps, and explains the effect.

This paper introduces the loading mode of ethylene glycol trucks on site. To improve the loading capacity of ethylene glycol, the container tank truck can be loaded temporarily when the number of tank truck is not sufficient, so as to improve the efficiency of loading and delivery. Through the analysis of the structure of container tank truck, some measures including transforming the loading port interface and changing the loading mode of container tank truck were taken to increase the total loading capacity and significantly improve the ethylene glycol delivery benefit.

The condensation effect of the overhead condenser in propylene rectification tower gradually decreased after the first start-up, resulting in the overpressure of the tower and the serious waste of propylene in the bottom of the tower, which brought great economic losses and potential safety risks to the plant. In order to solve this problem, the insufficient water supply of circulating water station and the biological fouling were ruled out one by one by analyzing the fouling of heat exchange equipment and taking a series of measures. It was judged that the main reason is the particulate fouling in circulating water of condenser, and a scheme was formulated to switch out the condensers one by one for hydraulic cleaning. Finally, the heat exchange efficiency was restored, the production bottleneck was eliminated, and the production demand was met. At the same time, the causes of particulate fouling in condenser were analyzed and relevant optimization measures were taken for the propylene rectification tower, so as to delay the fouling and impurity blockage and make preparations for the subsequent cleaning.

The connection between pipeline and rotating equipment, such as the connection between pipeline and pump and the connection between pipeline and compressor unit, is common in the piping installation of chemical plants. The suction / discharge pipeline of compressor has large diameter, high technical requirements for piping, and strict requirements for installation quality and internal cleanliness of pipeline. In order to avoid displacement or vibration of compressor during operation due to pipeline adhesion stress, which will affect the normal operation, stress-free piping must be carried out during the installation of its connecting pipeline, and this is particularly important for the compressor. In the piping construction of cracking gas compressor unit in the ethylene plant of PetroChina Dushanzi Petrochemical Company, the stress-free piping technology has been adopted successfully. Through practice, summary and refinement, this paper discusses the construction technology of stress-free piping and standardizes its construction method.