Machines and Apparatuses of Chemical Plants. Machines and Apparatuses of Oil and Gas Industry
This article is devoted to the study of fluid flow in the shellside of shell-and-tube heat exchanger.
Heat transfer in shell-and-tube heat exchangers is a complex process depending on many factors: the fluid properties, the geometric parameters of the flow region, the quality of the heat transfer surface caused by physical properties, surface roughness and fouling rate
Selection of the optimum ratio of geometrical parameters in order to achieve maximum energy efficiency of the heat exchanger must be based on the study of thermal and hydraulic characteristics of the flow.
The most effective method for studying hydrodynamic and heat transfer processes is now the method of computational fluid dynamics implemented in finite element analysis systems. Advantages of CFD is the high speed of calculation, the accuracy and completeness of the result data, which gives an understanding of distribution and flow rates in the apparatus, pressure drop of the interior space as a whole and its individual regions.
The article describes a finite element model of the heat exchanger. Model consists of three domains (tubeside, metal pipe, shell-side) and the domain interfaces.
The simulation results give a complete picture of the distribution of of thermal and hydraulic parameters. Of particular interest is the flow in the shell-side, that has a more complex configuration. Simulation allowed us to estimate the distribution of the fluid flow, to determine the qualitative and quantitative characteristics of the influence of gaps and baffle spacing.
The efficiency of heat transfer in STHE can be increased by restricting dead zones formed near the cross baffles. For this purpose, еру use of the additional baffles, promoting more uniform flow distribution is offered. The results of investigations of the additional baffles influence on efficiency of heat transfer in shellside were carried out in this article.
An analysis of technological peculiarities of execution repair-welding under internal pressure pumped Wednesday for manual arc and semi-automatic welding in protective gas Wednesday.
It is shown that when repair-regenerative welding metal pipeline wall various injuries under internal pressure working Wednesday formed favorable conditions for the formation of high-quality and reliable welds.
Found that when repairing welding electrodes austenite intense pipes from heat-resistant steel 15X5M martensite class comes increased resistance to brittle fracture, the values of which are almost at the level of indicators of base metal and substantially higher than when performing welding operations without pressure.
Metal welding seam under internal pressure in the vessel, has a more homogeneous austenitic-dispersed ferrite structure compared to the seam, made without pressure.
About suture structure of zones is fine-grained equilibrium bejnit structure with distributed relatively evenly dispersed source carbides.
There are virtually no plots overheating martensite acicular nature, hardening and decreases the level of residual welding stresses in dissimilar repair welded connection.
Marked changes in structural-mechanical heterogeneity at welded up intense damage pipes under internal pressure had a beneficial effect on strength and plastic properties have led to increased resistance to cold cracks and brittle fracture after repair-regenerative welding.
With, is technologically very complex and energy-intensive subsequent high temperature heat treatment of welded joints made of the apparatus. It is shown that the developed technology of welding with RTTS in automatic welding in shielding gases, welding wires austenitic heat-resistant steel 15H5M martensitic structural class allows to provide in the heat-affected zones (WJZ) obtaining bainite instead of martensite structure with high fracture toughness and at the same time homogeneous dispersion structure of austenitic weld metal. Due to the hardening of the austenite, avoiding excessive heating reduces the probability of formation of hot cracks austenit the seam, increases the corrosion resistance cracking, as when welding in layers,and the concomitant forced cooling adjustable. Thus by providing a compressed thermal cycles of welding, there occurs a reduction in the width of the active zones with a corresponding decrease in the values of residual welding stresses in the welded connection. Achieved greater generality of the grain boundaries of fine-grained bainitic ordered structure in the heat-affected areas of overheating of welded steel and the dispersed structure of the austenitic weld metal in the zone of fusion with minimal distortion of the microstructure in the fusion zone of the dissimilar joints. The introduction of the received results allows to improve technological and structural strength of welded joints, welding is used on the forced modes and to expand the scope of welding technology sabaliauskas heat-resistant steels without the use of heat treatment in the production of petrochemical equipment and pipelines, reduce the cost of welded equipment.(The purpose of developing resource-saving of technological process of manufacture of welded southwest of shielding gases in austenitic welding wires with high-temperature steel 15H5M regulation with the use of automatic welding thermal cycles (RTC). Technical and economic efficiency of the developed technological process of welding is ensured by eliminating preliminary and accompanying heating during welding to 250-350.
APPLICATION OF SENSORS-SIGNALER SAND AND DRIP MOISTURE TO THE MONITORING MODE OF THE WELLS UNDERGROUND GAS STORAGE
The article shows the relevance of monitoring the removal of particulate matter and condensed moisture in the product UGS wells, gas and gas condensate fields. Comparative characteristics of used domestic and foreign acoustic control in the gas flow phases is given. Particular attention is paid to the simultaneous control of the content of sand and condensed moisture alarms sensors that do not require expensive verification schemes and allow reliable assessment of the dynamics of the processes at the wellhead and gas gathering points. The results of operation of the combined alarm sensor DSS-AKE-2 on the two largest domestic UGS. The necessity of a direct calibration of acoustic sensors on the technological objects of different configurations is set. It is shown that the currently used in advanced devices such as DSS-A modification and the production of “Sigma-Optic” in performance is not inferior to foreign analogues in the implementation of operational monitoring wells operating parameters. The devices allow a timely manner to prevent flooding, the formation of clay-sand plugs, as well as reduce the risks of abrasive destruction of gas production equipment. The analysis of existing designs of detectors and alarms sensors showed that the sensor performance DSP-AKE-2 is not inferior to any domestic or foreign analogues, and for the simultaneous control of sand and condensed moisture superior to them and may be subject to import substitution. They can be used to predict the destruction of the reservoir, the formation of clay-sand plugs, reduce erosion-corrosion wear of gas production equipment and to minimize the costs of cleaning and preparation to transport gas.
Pilot and settlement studies whenever possible of use of the tubular turbulent device the design diffuser-konfuzornoy are conducted at an obessolivaniye of gas condensate. It is revealed that, from the point of view of small pressure difference on the ends of the device and efficiency of hashing, the relation of diameter of the diffuser to diameter of a confusor equal 2.0 is optimum. On the example of gas condensate of the Tolkyn field of the West of Kazakhstan it is shown that mixture of gas condensate with a small amount of fresh water (0.5 … 2% about.) in the tubular turbulent device allows to reduce the general content of salts from 95 g/m3 to 15 … 20 g/m3.
One of effective ways of target use of the high-boiling hydrocarbons of associated oil gas is their partial extraction by single absorption by stable oil. Distinctive feature in this process is prevalence of a gas phase. The conducted pilot and settlement studies have shown that at the relation of diameters equal 3.0 turbulization of mix on all length of the device with pressure difference less than 0.02 MPas is carried out. On installation of preparation of oil of the Rumayla field of the South of Iraq at a trailer step of separation at a temperature of 55 оC and pressure of 0.18 MPas about 0.84 t/hour of the associated oil gas directed to a torch are allocated. Use of the five-section tubular turbulent device and cooling of gas-liquid mix from 55 to 25 оC allows to reduce losses of hydrocarbons up to 40% of masses. Taking into account scaling it is recommended to use the five-section tubular turbulent device with diffuser-confusor design with a diameter of the diffuser of equal 240 mm, diameter of a confusor – 80 mm.