In order to solve the erosive wear problem of the straight pipe section of the sonicnozzle and the main flue gas pipe caused by the discharge gas (containing dust) from the three-stage cyclone separator, the paper simulates and studies the gas-solid flow characteristics in the sonic nozzle system based on CFD technology, using the k-ε model and the DPM discrete-phase model. The two-phase flow simulation results show that by optimizing the length of the straight pipe section and the nozzle installation angle, particle-wall collision results from sub-particles (1~10 μm) can be reduced, and the jet flow can be kept away from the main flue gas pipe, which is helpful to alleviate the wear problem of the system. The research conclusions can provide direction and guidance for the engineering design and optimization of the three-cyclone degassing system.

Plug leakage of air cooler is the most common and most likely problem in the operation of air coolers. Through comprehensive and systematic analysis on the plug leakage examples of air coolers, the causes of leakage are identified and the factors related to leakage such as plug materials, machining, structural design and installation methods are studied in depth. The effects of welding and structural optimization of air cooler tube box on plug sealing are discussed, and measures to solve air cooler plug leakage are proposed to reduce the hidden danger of leakage.

The structure of the oil inlet diffuser of storage tank can effectively reduce the oil flow rate, thereby reducing static electricity and the effect of water hammer load. In this paper, the standard k-ε model is adopted to numerically simulate the internal flow process of the oil storage tank based on the Fluent software, and the flow field characteristics of the oil inlet diffuser of the storage tank are analyzed. Studies have shown that the direct diffusion porous tube has high energy consumption, poor separation and diversion accompanied by the phenomenon of reverse flow; the curved diffuser has a good separation and diversion effect, and the liquid flow movement speed is relatively large, and it can drive the longitudinal development of the medium movement in the tank. The flow field is evenly distributed, which has a good stabilizing effect on the storage tank. It is recommended that curved diffusershould be chosen for the oil inlet pipe of the storage tank.

Themechanical impurity of lubricating oil, oil mud and varnishmay lead to abnormal working of the turbine speed control system and cause large fluctuations in turbine speed.The electro-hydraulic converter has poor adaptability to oil and its own stability is not good, which may cause frequent faults of speed regulation system as well. This paper analyzes the specific hazards caused by such factors as mechanical impurity of lubricating oil to the electro-hydraulic converter, the pilot valve and the oil relay. It also lists the frequent fluctuation cases of steam turbine speed. Based on the analysis results, it is confirmed that main reasons for the fluctuation of steam turbine speed of the TM-25LP electrohydraulic converter was the deterioration of lubricating oil and the generation of varnish.In order to detect this problem in time, the laboratory index of lubricating oil was increased. Meanwhile, the dual filter was added to the control oil pipe to prevent the influence of mechanical impurity and oil mud on electro-hydraulic converter.Aiming at the problems of the TM-25LP electro-hydraulic converter, upgrading and transformation of the electro-hydraulic converter was carried out. In addition, corresponding targeted measures were proposed to improve the quality of the lubricating oil.

White viscous materials were found in the washing tank at the outlet of the feed gas compressor of Yakela Gas Collection and Treatment Station. The liquid level gauge and blowdown valve of the washing tank were blocked by the viscous materials, which induced the shutdown of compressor at high level of washing tank. The natural gas was forced to vent and the light hydrocarbon yield reduced, which resulted in the serious damage to the economic benefits. This paper analyzes the reasons for the shutdown of the feed gas compressor at Yakela station from such aspects as the operation of the feed gas compressor, the dissolution experiment of white viscous materials and the operation mode. It is preliminarily determined that the whiteviscous materials are long-chain polymer substance contained in feed gas or wax and heavy hydrocarbon in natural gas, which is produced after compression and heating by compressor. Grounded in this, the paper proposes the countermeasures for reducing or avoiding the shutdown of compressors.

The main air blower set of catalytic unit is affected by operating conditions; the operation failure rate is relatively high; the duration of unit vibration degradation is long; and the level of Prognostics and Health Management (PHM) needs to be improved. Taking the maintenance of a petrochemical main air blower set as an example, this paper establishes a training prediction model based on the long short-term memory networks which collects and trains the data in the abnormal stage of unit vibration, predicts and fits the vibration trend of the unit. Then it puts forward optimization suggestions on the fault handling action and the timing of inspection and maintenance, and makes an attempt at predictive maintenance. These help torealize the improvement of unit health management.

In the running process of the reactor in an MTO plant, cracks appeared in the top seal head welds, resulting in product gas leakage. During the subsequent downtime overhaul, the reactor was inspected andanother non-through crack flaw was found nearby the same leakage crack welding seam. By taking a sample from the non-through crack, a professional inspection company was entrusted to conduct macroscopic inspection of cracks and microscopic analysis of chemical composition, ferrite content, hardness, metallurgy, fracture, radiographic energy spectrum and so forth. The causes of cracks were analyzed and discussed in terms of reactor design, manufacturing, installation, and service conditions. The results indicated that the cracks had the characteristics of intergranular cracking; the high temperature creep generated by the features of austenitic stainless steel welding and high temperature conditions and the structure instability in the hemi-ellipsoid head stress distribution were the internal causes of the cracking. The temperature difference stress instantaneous peak due to insulation failure of the top seal head was the external cause of the cracking.

In order to realize the delivery of fuel cell hydrogen in advance, a liquid driven compressor is used in the hydrogen filling station to boost the high-purity hydrogen into vehicles. The application comparison and analysis with the diaphragm compressor commonly used in hydrogen filling stations show that the liquid driven compressor has the advantages of structurally preventing hydrogen from being polluted, starting and stopping at any time, ready to use, low wear and low noise, etc. Compared with diaphragm compressors, the application of liquid driven compressors can reduce investment by about 20% and reduce filling energy consumption by 10%~30%. It has the advantages of site adaptability and strong competitiveness. This paper puts forward some suggestions for model improvement and development potential which can be used for the development of 2 000 m³/h (normal condition) large displacement model and the flow control of start-up conditions and can improve the technology in further energy saving and consumption reduction.

The corrosion of water cooler is a common challenge for petrochemical plants, which is related to the safe and stable operation of the plants. This paper summarizes the corrosion mechanism of water coolers, introduces the coating anti-corrosion system of water cooler established by SINOPEC grounded in the industry standard SH/T 3540, and discusses several related hot issues covering the influence of coating anti-corrosion on heat transfer efficiency, the application of coating anticorrosion in petrochemical plants, and the application of coating anticorrosion on the oil & gas side of heat exchangers. Coating anti-corrosion is still the main anticorrosion means of water coolers in petrochemical plants, and the goal of more environmental protection and longer service life should be pursued.

The service life of air preheaters is often affected by the occurrence of dew point corrosion. This paper introduces the mechanism of low temperature dew point corrosion and the improvement method for preventing the corrosion of air preheaters. The use of corrosion-resistant materials and coating technologies can slow down corrosion. Flue gas desulfurization and controlling the cold-end metal surface temperature of the preheaters above the dew point temperature can prevent corrosion. The measured dewpoint temperature of sulphuric acid in a gas flame heater is 78 ℃ which is used for pre-heater cold-end temperature control. The company applied two new technologies including "95+ high-efficiency industrial furnace technology" and "composite phase change heat transformer waste heat recovery technology" to prevent dew point corrosion, which achieved good results.

In order to meet the process requirements of low pressure drop, furnace tube in the radiation section of Continuous Catalytic Reforming (CCR) furnace adopts the "U" type or inverted "U" type furnace tube configuration which is different from the heating furnace of general oil refining units. Based on its special furnace tube configuration, the convection section of CCR furnace cannot recover the waste heat of high-temperature flue gas in the radiation section by means of flue gas heat extraction of preheating process. This paper discusses and analyzes the waste heat recovery schemes for flue gas from CCR furnace, which has been applied in petrochemical industry. By comparing the influence of economic and social effects under different flue gas middle temperature conditions, the concept of "mid-section temperature of economical flue gas" is proposed, and the method of selecting "economic flue gas middle temperature" is obtained through summary. The conclusion of this paper provides a necessary theoretical basis for optimizing the scheme of recovering high-temperature flue gas waste heat in the radiation section of the CCR furnace of the CCR unit and further improving the overall economy of CCR furnace.

Aiming at the problem of high position design of the pump oil gauge, which may easily cause the operator to misjudge the lubricating oil level in the bearing box, a siphon lubricating oil level indicator is selected for replacement. A siphon is added at the joint between the oil gauge and the bearing box, which can truly reflect the liquid level of lubricating oil in the bearing box. This paper introduces the whole research and development process of the new oil level indicator. The application of such new oil level indicator fundamentally solves the problem of oil rejection caused by excessive lubricating oil in the bearing box of the pump, and this provides guarantee for the smooth operation of the pump.