As a clean and effective new energy, fuel cell is regarded as one of the most important energy technologies. Proton conduction in solids has attracted much interest because of its potential application in fuel cells. Metal⁃oxalate compounds constructed by metal ions and oxalate are a sense of inorganic⁃organic hybrid compounds, which have emerged as a new class of proton conductors because of their controllable structures and high chemical variety. We summarized the proton conduction properties of main group⁃oxalate compounds, transition metal⁃oxalate compounds and lanthanide metal⁃oxalate compounds, and their future development was prospected.
Using CO as the probe molecule, infrared diffuse reflectance spectroscopy was used to study the adsorption of Pd⁃Ag/Al2O3 catalysts prepared by impregnation method and the carbon monoxide adsorption on the support and a series of changes in the surface species of the catalyst. The results showed that in the Pd⁃Ag/Al2O3 catalytic system, due to the different order of silver addition, the active center of the catalyst was affected by the electronic effect and the geometric effect, which caused the surface species adsorption morphology of the catalyst after CO adsorption. It was found that there was no bridge adsorption of CO on Pd⁃Ag/Al2O3⁃LM⁃2 catalyst when CO was adsorbed and desorbed before and after heating. The characteristic peak intensity of HCO〖_3^-〗 was found decreased with the increase of CO adsorption and desorption temperature. At the same time, the adsorption characteristic peak of HCOO- was relatively enhanced, and the consistent growth and decline relationship between the two indicated that HCO〖_3^-〗 was converted to HCOO- during the heating process.
Chemical precipitation method was applied in for separation and recovery of valuable metals molybdenum, vanadium and aluminum from alkaline V⁃Mo⁃Al solution. By the theoretical calculation and conditional experiments, the effects of precipitating agent dosage, temperature, pH value and deposition time on the precipitation separation of molybdenum and vanadium in alkaline solution were investigated detailedly. The results showed that when CaCl2 was used for vanadium precipitation, the reaction temperature was 80 ℃, the addition of CaCl2 was 1.1 times of the theoretical addition, the time was 1 h, and the pH was 12.9,over 95.3% of vanadium was precipitation recovered. When molybdenum was recovered by Ba(OH)2, under the optimum conditions of temperature 80 ℃, Ba(OH)2 dosage 1.1 times the stoichiometric amount, reaction time 60 min,the precipitation rate of molybdenum was up to 99.6%.
S⁃Zorb reaction adsorption desulfurization technology has become one of the important gasoline deep desulfurization technologies because of its high efficiency desulfurization effect and mild process conditions. S⁃Zorb desulfurization technology was developed by Phillips company and has been widely promoted in China since it was exclusively acquired by Sinopec. However, the composition of its adsorbent has not been fully published. Therefore,the focus of the S⁃Zorb process research is on the localization of the adsorbent at present, and the activity and stability of the desulfurizer are continuously improved through in⁃depth research on the reaction adsorption mechanism. The process development and existing problems of S⁃Zorb reaction adsorption desulfurization technology and the latest progress of research and development of S⁃Zorb reaction adsorption desulfurization agent were reviewed, and the mechanism of reaction adsorption desulfurization was discussed.
In recent years, horizontal well fracturing water injection huff and puff technology has become the main development technology of tight oil.In the initial stage of water injection huff and puff, higher production was achieved,however,with the increase of huff and puff times,the production decreased rapidly and the oil⁃water replacement efficiency was low.Based on the compact oil data of Jimusaer Oilfield in Xinjiang,through laboratory core water injection huff and puff experiment and single well water injection huff and puff numerical simulation research,the effects of injection volume,time of water injection huff and puff,injection speed, huff and puff times,soaking time and production speed on water injection huff and puff recovery are analyzed.The single well geological model is established,and the influencing factors of water injection huff and puff are fitted by multi⁃nonlinear function.The empirical formulas of five parameters and three parameters of water injection huff and puff are deduced for the first time. The prediction error is within 8%, which provides important reference for the development of water injection huff and puff in the study area and similar tight reservoirs.
At present, due to active edge water in BQ57 area of target oilfield, the reserve recovery is low. Therefore, it is necessary to study the remaining oil in BQ57 area to ensure good results in thermal recovery process. The distribution law of remaining oil in vertical and plane of layers III 1 and 3 in BQ57 area is studied. The total remaining oil is 43.22 ×104 t. In the vertical, the geologic reserve of layer Ⅲ11 is 17.76×104 t. The remaining geological reserves are 14.72×104 t. The degree of reserve recovery is 17.19%. The geological reserve of layer III12 is the smallest, which is 5.79×104 t. The remaining oil is also less, which is 4.86×104 t. The degree of reserve recovery is 16.09%. The remaining oil in layer III31 is the largest, which is 15.4×104 t. The degree of reserve recovery is 11.20%. The remaining oil in layer III32 is 8.26 ×104 t and the degree of reserve recovery is 6.17%. On the plane, the proportion of remaining geological reserves channel is 52.87% in underwater distributary. Because its distribution area is largest, the proportion of remaining oil is the highest and the value of reserves abundance is the highest. The proportion of remaining oil in front sand sheet is 44.98%. Its value of reserves abundance is also higher. The latter adjustment of well pattern needs to be combined with the productivity potential of a single well, the underwater distributary channel and front sand sheet should be given priority in the adjustment of well pattern.
Network fracturing is one of the key technologies to enhance the recovery of peripheral tight reservoir in Daqing. In order to explore and improve fracturing effect and economic benefit of fracture network fracturing, it is necessary to further study the influential factors of initial productivity. Aimed at the problem which the correlation degree between the initial production capacity and the influencing factors calculated by the method of traditional mathematical statistics is almost the same. The improved grey correlation analysis (IGCA) is applied to modifying the original model. To analyze the degree of correlation between initial production and effect factors after fracturing, determining the main influencing factors, and the correctness and practicability of this model was verified by examples. The research results show that，under the conditon that seepage field was not changed,it is necessary to improve the formation pressure and enlarge operation scale,so as to improve the network fracturing vertical well fracture network fracturing in tight oil reservoir. The method presents the reliable basis for fracturing design and result evaluation in tight oil reservoir.
The lattice Boltzmann method is widely used in the simulation of digital core porous media flow because it can handle complex geometric boundaries.The digital core section of the Dongying formation reservoir in the Bohai S oilfield is taken as the research object. Based on the image processing, the lattice Boltzmann method is used to carry out the two⁃dimensional pore flow simulation and velocity field characterization. By changing the simulation conditions, the different production pressure differences are analyzed. The effect of pore throat optimization on the slice seepage channel. The results show that the production pressure difference can only change the seepage strength of each channel. The rock pore size is the main factor affecting the distribution of the seepage channel. The pore throat optimization can effectively adjust the seepage channel and improve the microscopic pore wave degree.
Since 2016, Ansai oilfield has carried out polymer microsphere profile control and flooding, which has experienced three stages: pilot test, expand the scale of the test and promotion of three stages. The regional stage decline can be reduced about 5%, the overall effect is obvious, but the adaptability and application effect under different reservoir conditions are quite different, For the study of polymer microspheres in multiple media under the condition of mechanism, a group of 60 different particle size of polymer microspheres in different media under the condition of displacement test was carried out. Through the combination of experimental data and field application, the mechanism of microsphere oil displacement (percolation mechanism, change of flow direction mechanis) and the matching relationship between microsphere particle size and reservoir microfractures and pore throat are systematically summarized,which provides a basis for the optimization of construction parameters in the later stage.
The dispersion characteristics of droplets in swirling turbulent flow field is a difficult problem in the process of fluid mechanical design and optimization. A new concentric rotating cylinder is used to obtain uniformly distributed flow field. On the basis of Hinze's model, the influence of oil droplet viscosity on oil droplet dispersion characteristics is considered. The relationship between turbulent flow field and oil droplet dispersion characteristics is preliminarily discussed. The empirical relationship between flow field characteristics and oil droplet dispersion characteristics is obtained when Reynolds number is 5.5×104~2.4×105 and relative centrifugal force is 21.9~643.3.The research on dispersion characteristics of oil and water in swirling turbulent field is improved, which provides a new research idea for the liquid⁃liquid dispersion characteristics in swirling turbulent flow field.
The reserves of natural gas hydrate determine its potential commercial development value. Combining the composition of seabed sediments and the seabed environment, the experiments were conducted to study the effect of calcium carbonate as a porous medium and sodium dodecyl sulfate (SDS) on methane hydrate formation under the conditions of 2 ℃ and 6.08 MPa and its mechanism was analyzed. The results show that the gas storage effect and gas storage rate of the two synergistic systems are better than pure SDS solutions. Changes in the particle size of calcium carbonate could change the amount of hydrate formation and gas storage effect, of which 1 mm calcium carbonate has the best gas storage effect. The synergistic system greatly shortens the induction period of hydrates and accelerates the rate of hydrate nucleation. The promotion effect of the synergistic system is reflected in the promotion effect of SDS and the promotion effect of calcium carbonate surface characteristics and particle size changes and its adsorption characteristics. It breaks the micelle effect of SDS and the "solid sealing" effect of hydrates, increases the formation rate of hydrate in heterogeneous heterogeneous environment, and promotes hydrate formation. Therefore, the synergistic system of porous media and surfactant can significantly improve the hydrate generation rate and gas storage effect, and provide a theoretical basis and research direction for the rapid hydrate generation technology.
After the start of the heating furnace in the upstream station of the hot oil pipeline, the unsteady trend of the oil temperature in the downstream inlet station will affect the hot⁃washing operation of the pipeline before the pigging and the emergency treatment for abnormal shutdown. Accurate prediction of unsteady oil temperature trend changes can effectively improve the safe operation of pipelines and energy conservation and consumption reduction. A deep learning framework is adopted to take the unsteady process of upstream and downstream oil temperature as the mapping relationship from sequence to sequence, and the classical seq2seq algorithm of Recurrent Neural Network (RNN) was used to establish a predictive model of unsteady oil temperature. Through the correlation analysis, the parameters such as the unsteady oil temperature, pipeline flow and ground temperature in the upstream outbound station are selected as the model influence factors. In the SCADA system database of the HY hot oil pipeline, the relevant parameter historical data is downloaded as sample data, and after the data is preprocessed, the model is trained and tested. The error between the predicted value and the true value is ±0.2 °C, the correlation coefficient R and the root mean square difference RMSE are 0.96 and 0.99. At the same time, the verification model can effectively predict the unsteady oil temperature of the downstream station, which has high accuracy and good generalization.
When the traditional CFD method is used to solve the Navier⁃Stokes equation of incompressible flow, the pressure equation has an elliptical shape and cannot be solved, and the convergence is poor. Therefore, the traditional CFD method has certain limitations. In order to study the computational efficiency and accuracy of the lattice Boltzmann method compared with the traditional CFD method, taking the thermal diffusion problem of plates with constant temperature boundary as an example, the temperature field between the plates is solved by the finite element volume method, the finite difference method and the lattice Boltzmann method. By comparing the solution results and the number of normalized iteration steps, the feasibility, accuracy and efficiency of the lattice Boltzmann method are clarified. The results show that under the same physical model, the lattice Boltzmann method and the finite difference method are slightly better than the finite element volume method. The lattice Boltzmann method has the fastest solution speed and the least iteration steps, followed by the finite difference method, and the finite element volume method has slowest solution speed.
The computation fluid mechanics was used to simulate the fluidization characteristics in fluidized bed with tridimensional rotating sieve tray under different operation velocities (0.44~1.14 m/s) with using of Eulerian⁃Eulerian multiphase model. The progress of bubbles formation, growth and vanishing was studied by analyzing instantaneous solids volume fraction in the fluidized bed at different time under different velocity, velocity vector distribution map at different time, variation of solids volume fraction in the baffled bed at different position under different velocity and variation of solids volume fraction in the baffled bed at different time under different velocity. The simulation results showed that the calculated values were agreed well with experimental results，the average deviation between calculated data and the free bed data is 13.4%，that between calculated data and the sieve tray bed data is 7.59%. It indicated that the model can predict the fluidization characteristics of solid particles under different operating gas velocities and simulate the progress of bubbles formation, growth and vanishing. The spray phenomenon occurs in the upper region of the rotating sieve tray, forming a fountain with low solid volume fraction. The addition of rotating sieve tray can break big bubbles into small bubbles and strengthen gas⁃solid mixing.
Aviation kerosene uses jet fuel No.3 (JET A⁃1), which is a common source of danger in leaking fires.Based on theoretical analysis and PHAST software simulation, the influence of a tank leak in the aviation coal tank area on the surrounding storage tank was studied. The method for determining the safety distance between the tanks was introduced. The results show that the thermal radiation intensity increases with the increase of wind speed, and the thermal radiation value at the maximum wind speed increases by 65.7% compared with the average wind speed. As the distance increases, the radiation value becomes smaller, and as the height of the tank increases, the heat radiation value becomes larger, and the atmospheric humidity has less influence on the heat radiation. It is determined that the safety distance of the oil tank of the project is 17 m. The theoretical calculation is carried out by using MATLAB software and compared with the numerical simulation results. The maximum error is 18.7%, which has strong reliability. The research results have important theoretical and practical significance for tank tank design and guiding emergency disaster relief.
