Li Xin Wei

Heat Loss Test and Estimate for the Large-scale Floating Roof Tank

The heat loss and surface temperature of the top surface and sidewall of large-scale floating roof tank is tested by the heat flow meter and surface temperature method. Based on the test data, the heat loss from the top surface is about twice more than that of the sidewall which means the top surface is the weakest insulation part of the floating roof tank. On the surface, the heat loss profile is in accord with the surface temperature distribution. Special attention is given on the calculation of thermal conductivity for the top surface and sidewall which finally deduced the total heat transfer coeffi- cient of large floating roof tank. Moreover, the heat loss of floating roof tank in different working conditions is predicted. According to the calculation results, the level of 6m is regarded as a critical level determining the heat loss. And the cen- tralization storage of oil is a more energy conservation storage pattern. Nowadays, in order to avoid the energy crisis, an increas- ing attention is given on the energy storage in many coun- tries. As one of the most important primary energy, the stor- age of crude oil always dominates in the existing energy sys- tem. With the increasing storage scale of crude oil, the heat dissipation during the storage course draws many peoples attention. Especially in the cold region, for the storage of waxy crude oil, the heat loss is considerable. For many large crude oil depot, the floating roof tank has become the pre- ferred facility to store oil. But due to the specific construc- tion, the heat loss from the different part of the tank is diffi- cult to ascertain. Normally, the theoretical calculation based on the heat transfer theory is induced to investigate the heat loss, Busson and miniscloux (1) developed a simple model to predict the steady state heat losses from a fuel oil tank based on the as- sumption of a well-mixed core of fluid. Kumana and Kothari (2) proposed empirical correlations for heat transfer coeffi- cients of the tank and published a model to predict the cool- ing rate of oil. Venart (3) solved the governing natural con- vection equations to investigate the steady state heat losses from a fuel oil tank. Cotter and Michael (4-6) presented a simplified heat loss model based on the numerical calcula- tion of heat transfer in the oil tank. Moreover, the effect of heat transfer coefficient, aspect ratio and temperature de- pendent viscosity on the fluid flow and heat transfer was examined. In general, most research takes the dome roof tank as the research object, the heat loss rule of which is very different from the float roof tank due to the different roof construction. Together with the complex heat transfer course which is difficult to characterized, the actual measurement is still regarded as the most effective method. As mentioned above, the actual measurement of heat loss from floating roof tank has not been reported in the litera- ture. The aim of this work is to investigate the heat loss from the different part of the floating roof tank, and special atten- tion is given on the heat flux from the top surface and the calculation of thermal conductivity for air layer in the top surface. The surface temperature of the tank is also tested to estimate the inner temperature profile of oil. Moreover, the total heat transfer coefficient of large floating roof tank is proposed to predict the heat loss in different working condi- tion which is significant for the management of the oil depot, in the meantime provides the basis for the energy-saving and efficient storage of crude oil.

Third-Party Damage Factors Analysis and Control Measures of Daqing-Harbin Oil Pipeline

The third-party damage is the main factor of Daqing-Harbin oil pipeline failure. This paper analyzes a variety of factors causing the third-party damage, and establishes the fault tree model. By analyzing the minimal cut set and structures importance degree of fault tree, the main factors of the third-party damage that caused pipeline failure are determined. The main factors are as follows: Lack of pipeline conditions, human vandalism, the frequency of line patrol and management systems, lack of public education and the legal concept, and construction operation injury. On the basis of analyzing the factors, the precautions of the third-party interference are proposed.

Deformation Characteristic Evaluation of Large Oil Storage Tanks under the Planar Inclined Foundation

Oil storage tank plays an important role in modern oil industry. The development of large-scale oil storage tanks has resulted in the complexity of stress distribution and deformation situation of tank wall and tank bottom. Especially in soft foundations, the tank structure is susceptible to various types of settlement deflections. The most common type is planar inclined foundation. In this paper, the finite element model of large-scale oil storage tank was built according to the pattern of design and the deformation characteristic and stress distribution of large storage tank under the planar inclined foundation was obtained. Considering the floating roof, the ultimate value of large storage tank under the planar inclined foundation is determined.

Study on Technical Limits of Single-Pipe Concatenation Gathering Process during High Water-Cut Stage

In order to optimize the gathering system and reduce the energy consumption in the production, single-pipe concatenation process has been widely used after the tertiary oil recovery technique is applied and development enters into high water cut stage in the oilfield. Aiming at condensate oil in gathering pipeline and obvious increase of the high circle pressure wells in the operation of the process, the adaption relationship between oil gathering pipeline size and flow, as well as the temperature limit of the gathering system start are studied, through the hydraulic and thermodynamic calculations of oil-gas-water multiphase flow. It has directive function for making effective schemes to solve the production problems caused by the high back pressure of wells.

Research on Petrochemical Industry with Analysis of Floating Roof Tanks under the Planar Inclined Foundation

Floating roof tanks constructed in soft foundations are susceptible to settlement deflections. The most common settlement type is planar inclination. In this paper, the FEM is used for the study of deformation shape and stress distribution of floating roof tanks which have different diameter under the planar inclined foundation. The allowable settlement values were determined. And they were compared with the current national standard. The result indicated that the finite element analysis results were greater than the allowable values set in the current national standard. The allowable values set in current national standard for floating roof tanks under the condition of planar inclined foundation are conservative. Reasonable criteria should take into account the effects of structural response to the foundation displacements.

Stress Analysis for Safety Evaluation of Subsea Pipeline Based on Material Properties

Subsea pipeline has been wildly used in the offshore oil exploitation, and its operational safety has profound significance to the subsea oil industry. In this paper, an actual operating subsea pipeline, which is a typical structure of pipe-in-pipe system, is selected as the object of study. Based on finite element method, the stress analysis is carried out. Results show that the residual ultimate strength of the current damaged pipeline is founded and the damage greatly increased the stress state of dented region of the pipeline.

Structure Analysis of Large Steel Crude Oil Tank under the Planar Inclined Foundation

Large steel crude oil tanks constructed in soft foundations are susceptible to various types of settlement deflections. The most common type is planar inclined foundation. In this paper, the FEM is used for the study of deformation characteristic and stress distribution of large steel crude oil tank under the planar inclined foundation approaching to critical value. Results show that deformation characteristic of tank is unevenness; max stress in tank shell occurs in middle-low part of floating roof tank; the ultimate value of large steel crude oil tank under the planar inclined foundation is 0.89m.

Energy Consumption Analysis and Comprehensive Optimization in Oil Pipeline System

By three-link modal, the energy consumption pattern of oil pipeline system was divided into the energy conversion process, transmission process and technological utilization process. The mathematical model of energy consumption analysis and scheme optimization of pipeline system were established. And on the basis of .Net platform, with the OLE DB database connection technology, The software of energy consumption analysis and comprehensive optimization of oil pipeline system was developed which can be used as a tool to help the pipeline manager to manage the pipeline more effectively.

A Case Study in Oil-Gas Transportation through Subsea Pipeline in Liaohe Tanhai Oilfield

The crude oil in Kuidong region of Liaohe Tanhai Oilfield is characterized by high oil viscosity, high density, high content of colloid asphalt, low content of wax and low freezing point. In the shallow region, the large current, high content of silt, long-distance subsea buried pipeline and drift ice in winter have brought great challenge to offshore construction and oil-gas transportation. In this paper, the investigations of offshore construction project and platform process are shown. Based on the well production rate, gas-oil ratio, water cut, wellhead back pressure and outlet temperature, the range of daily transportation volume was acquired, as well as the maximum inlet pressure and pressure difference of the pump. The paper also selected technically and economically feasible pumps, then designed the public projects, corresponding electric power and self-control facilities. The selected skidded twin screw multiphase pump system can smoothly transport produced liquid to the terminal systems onshore without any effect on the daily output.

Hydraulic Calculation Method Study of Branch Shape Water-Injection Pipe Network Based on Binary Tree

On the basis of analyzing process and structure characteristics of branch shape water-injection pipe network, this paper established a hydraulic calculation method of branch shape water-injection pipe network based on binary tree. This method has many advantages, such as calculation speed is fast, occupying less memory, having high calculation accuracy, and so on. According to it, this paper compiled a computer program and presented an actual example.