This paper presents five typical design types ofleanrichcarbonate exchanger for EO/EG plant covering segmental baffle fixed tubesheet exchanger, segmental bafflefloating head exchanger, segmental baffle Utube exchanger, rod baffle exchanger and allwelded plate exchanger. It analyzes and compares the performance characteristics of each type of heat exchanger, the characteristics of applicable process fluids, and the differences in plant's occupation of land, equipment cleaning and cost and so forth. Then, according to the merits and demerits of each type selection scheme, the paper presents the sequence of recommended selection schemes, which provides reference for the selection of leanrich carbonate exchangers of similar devices.

The fluid flow characteristics in the plate of plate-shell heat exchanger was calculated and studied by adopting Computational Fluid Dynamics (CFD) and three-dimensional numerical simulation method. The performance of different heat exchanger plates under the same working conditions was analyzed. The performance comparison in the tubes between the plate-shell heat exchanger and the ordinary heat exchanger were studied. The results show that, by taking the heat transfer coefficient α(i.e. comprehensive performance index, α=K/ΔP) of the unit pressure drop as the standard to measure the comprehensive performance of the fluid in the tube side of the heat exchanger, the comprehensive performanceis the bestwhen the oblique angle of the narrow channel of the plate-shell heat exchangeris 20° under the same tube-side flow conditionswith the advantages of small pressure loss and being not easy to scale; and the comprehensive performance index of plate-shell heat exchanger is better than that of the traditional tubular heat exchanger by 9%~26.9%. The heat transfer process isenhanced to a large extent. And this has very wide prospects for industrial application.

Taking the principles in API 521 as the guiding principles and based on engineering experience, this paper analyzes various working conditions that may cause overpressure in the ethylene-propylene-diene monomer (EPDM) polymerization reactor, such as fire, blocked outlet, control valve failure, chemical reaction, hydraulic expansion, and utilities failure. It focuses on the discussion of overpressure caused by thermal expansion of the liquid under external fire conditions and overpressure caused by reaction heat when chemical reaction is out of control. The paper calculates the required discharge capacityof safety valve under each working condition. The results show that the discharge capacity of safety valve is the largest under the condition of chemical reaction, 〖JP2〗reaching 47 520 kg/h, and the required discharge area of the〖JP〗 safety valve calculated according to the maximum discharge capacityis 415 mm2.

This paper describes and summarizes the requirements of ASME Ⅷ-1 code and different project documents on hydrostatic pressure test for pressure vessels. It also explains the relevant inputs and settings in the calculation software PV Elite. These can provide reference for the correct determination of the maximum allowable working pressure and maximum working pressure, and then the determination of the hydrostatic test values required by clause UG-99 in the code. Finally, different hydrostatic test values obtained under different project requirements are shown through calculation examples.

In a chemical plant, a fixed tube-sheet heat exchanger with a shell diameter of 4 000 mm has higher pressure, higher temperature and low-temperature operation requirements, larger diameter, and larger temperature differences in accident conditions. So, there are certain difficulties in material selection, tube sheet structure design and manufacturing plan. This paper introduces the design process of the heat exchanger in detail from such design links as material selection of the tube side and shell side cylinder, strength calculation, tube sheet forging scheme, material and manufacturing technical requirements, non-destructive testing and so forth. In order to meet the requirements of higher pressure and low temperature, 09MnNiD forge pieces plus surfacing material were selected as the tube box material, the tube sheet selected tube side and shell side ends with shoulder bolts made of 09MnNiD forge pieces and solid forging was chosen in the manufacturing plan; meanwhile, detailed test and inspection technical requirements were put forward for the entire manufacturing process.

Nitrogen oxides (NOx) are atmo-spheric pollutants which are extremely harmful to human health and ecological environment. And it's difficult to treat NOx. The nitrogen oxide emissions of a chemical furnace in a factoryexceed the standardseriously and must berevamped. This paperstudies the formation mechanism of nitrogen oxides (NOx) of furnace and the technical measures to reduce its emissions. According to the practical engineering project experience and the analysis on the specific conditions of furnace in-service, the paper proposes a feasible revamp scheme. On the basis of achieving compliance with nitrogen oxide emission standards, the scheme can ensure long-term stable operation of the equipment.

Aiming at the problems of frequent leakage and short life of the cyclic propylene compressor valve in polypropylene plant, it was foundthrough analyzing the failure factors of the air valve that improper selection of the air valve types was the main reason for the frequent fatigue fracture and the short life of the valve.Then the compressor valve was optimized through optimal selection of the valve type and the improvement of valve sheet material. Hence, the service life of the valvewas prolonged; the shutdown number of the cyclic propylene compressor was reduced; the pollution caused by propylene emission to the environment was avoided and meanwhile these created certain economic benefits.

This paper presents the structural and technical features of spiral wounded heat exchanger(HE). For the first time, technical comparison and economic benefit analysis have been made between aviation kerosene hydro-treating units adopting spiral wounded HE and conventional HE. Spiral wounded HE has such features as compact structure andhigh heat transfer efficiency. It is resistant to high temperature and high pressure. Multiple media participate in heat transfer simultaneously and there's no limit to differential pressure in such exchangers. The heat transfer efficiency of spiral wounded HE is two to three times that of the shell-and-tube exchangers. To achieve the same heat transfer efficiency, the floor spacecan be saved by more than 50%. So, it's widely used in various industries andwill gradually replace some conventional HE with its absolute advantages. Therefore, application of such high-efficiency energy-saving HT is recommended in aviation kerosene hydro-treating unitto realize the concept of energy-saving and environmental protectionand improve the economic benefits of enterprises.

Based on the modern construction technology, resource situation and the development trend of informatization of today'ssociety, this paper puts forward some useful suggestions on the ways and methods of modular prefabrication and installation of steel structure, non-standard equipment and pipelines during the construction process; meanwhile, it has made some explorations for improving the quality and efficiency of the project effectively in terms of safety, quality, construction period management and control and economic benefits. The paper also proposes the idea of implementing overall modular construction of DMTO unit, which provides reference for the modular construction of petrochemical projects.

Aiming at the crack defects of Q345R hot-rolled steel plate welding ring (transverse) welding seam (hereinafter referred to as girth welding) in the reactor-settler of FCCU, this paper analyzes the cracks on the base metal of the steel plate and welding joint from such aspects as the metallographic structure of the base metal and the weld, the impacts of the steel plate rolling process on the end edge stress and "weld brittle resistance" caused by secondary processing. Through adopting welding process optimization measures, the welding quality of the product is guaranteed.

Cryogenic methane pump is important equipment in ethylene production plant using cryogenic separation technology. Taking frequent mechanical seal failure of cryogenic methane pump as the starting point, this paper expounds the sealing mechanism of cryogenic methane pump. Itdeterminedfrom the analysis of the sealing mechanism that there were two causes for the leakage of sealing fluid. First was the poor self-lubrication effect of theside sliding bearing of the pump impellerwhich could not form stable lubrication liquid film, resulting in dry friction between the bearing and the shaft sleeve. And this led to the vibration of the pump and intensified the separation of the rotor-stator ring. Second was the smallinner diameter pressureratio of the bellows ring surface and the insufficient pressure resistance of the static and dynamic ring, resulting in big sealing pressure difference of the sealing cavity. According to the analysis results, the optimized transformation scheme was adopted to reconstruct the bearing and improve the self-lubrication effect. The original L-shaped torus was replaced by a rectangular torus with a section to improve the pressure ratio of the inner diameter of the sealed bellows. More pressure-resistant PG rectangular section was used for the seal ring and the seal ring materialwas upgraded. Meanwhile, the pump operation monitoring means was optimized toprolong the pump operating life and reduce unnecessary maintenance work.

Thefracture causes of the regenerative sliding valve guide bolt (GH4033) were analyzed through chemical composition and mechanical performance analysis, tensile test, meta-llographic analysis, fracture morphology and energy spectrum analysis. The results show that the bolt fracture is a high temperature creep fracture. The main cause of the bolt fracture is material lattice defects (lattice vacancies caused by impurity silicon) and intergranular fractures due to carbide precipitation in high temperature environments.

According to the leakage failure of the head of waste heat boiler at the outlet of high temperature transformer of the synthetic ammonia plant, this paper analyzes the equipment from such aspects as the structure, function and the blade seal technical transformation due to the insufficient heat exchange efficiency when the equipment being put into use at the beginning. The measures of online fastening and temporary bolt replacement were taken respectively. And it was found that the poor flatness of the sealing surface of the head flange was the main cause of equipment leakage during the shutdown and maintenance of the equipment. By machining and repairing the sealing surface of the head flange, the flatness accuracy requirements of the sealing surface were restored. And corresponding measures were taken to dismantle the tube bundle smoothly and replace the leaf seal, which ultimately eliminated the problem of head leakage and ensured the safe and stable operation of the equipment.