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Liu Z.,China University of Petroleum - Beijing | Liu Z.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Ji Z.-L.,China University of Petroleum - Beijing | Ji Z.-L.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 4 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2016

Particulate matter such as dust and free water is often entrained into coalbed methane (CBM),which affects the safety of the operation in gathering system.The on-line detection method for particulate matter was used to find out the distribution characteristic of the impurity in gas gathering system.Dust concentration and particle size distribution,free water and water vapor concentration can be obtained at the gathering nodes,including wellhead,manifold,gas gathering station and central treatment plant.It was found that the content of liquid impurities was large,and the impurities deposition phenomenon was obtained.The impurities were also captured for chemical composition analysis,which could affect the composition of solid impurities and the property of liquid impurities.Particulate matters were obvious different before and after the compressor.To deal with the problems of separation equipment,the improvement measure of existing filter element was proposed.The test in the laboratory and field proved that the improved element had lower resistance and higher efficiency.The improved filter element could effectively reduce the operation cost and is suitable for the CBM system with a low pressure characteristic. © 2016, Editorial Office of Journal of China Coal Society. All right reserved.


Zhang J.,China University of Petroleum - Beijing | Zhang J.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Xu C.,China University of Petroleum - Beijing | Zhang Y.,China University of Petroleum - Beijing | And 2 more authors.
Journal of Natural Gas Science and Engineering | Year: 2016

Liquefied natural gas (LNG) cryogenic submerged pumps are important transmission devices in LNG terminals and filling stations. In this study, the impeller of a two-stage LNG submerged pump was designed by the quasi-3D hydraulic design method based on the S1 and S2 relative stream surfaces theory. In the design procedure, the finite element method (FEM) with a quadrilateral nine-node element was adopted for the S1 stream surfaces calculation, and the quasi-orthogonal method was used for the average S2 stream surface calculation. The flow field was obtained by the iterative computations of S1 and S2 stream surfaces. Given a reasonable velocity moment distribution along streamlines considered cavitation, the blade drawing was realized by iterating the camber lines and circulation equations on an average S2 stream surface. Moreover, a steady numerical simulation of the designed pump was conducted. The simulation result showed that the head of the designed pump was 260.15 m and the efficiency was 62.82% at the designed flow rate condition. The net positive suction head required (NPSHr) at the conditions with 0.9 Q0, 1.0 Q0 and 1.1 Q0 were, respectively, 1.69 m, 2.54 m and 3.12 m, which met the industrial needs. Furthermore, both the cavitation and hydraulic performance of an impeller designed by the method presented in this study were better than those of an impeller which was designed by the two-dimensional method. © 2015 Elsevier B.V.


Zhao H.,China University of Petroleum - Beijing | Zhao H.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Jiang T.,China University of Petroleum - Beijing | Jiang T.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 2 more authors.
Energy | Year: 2015

The CCHP (combined cooling, heating, and power) system, especially combined with the SOFC (solid oxide fuel cell), has great potential for improving energy utilization efficiency. Therefore an integrated SOFC-CCHP system, fueled by COG (coke oven gas) which contains large amount of hydrogen, has been designed and proposed in this paper. The flue gas exhausted from the HRSG (heat recovery steam generator) is used for heating and the latent heat of water exhausted from the ST (steam turbine) is used for cooling achieved by a single-effect lithium bromide absorption chiller. Based on the corresponding models, the evaluations of the system performance are carried out aided by Aspen Plus process simulator. The calculation results indicate that the electrical efficiency of the SOFC can reach over 60% while the total power efficiency and the overall system efficiency of SOFC-CCHP system are about 70% and 90% respectively. Furthermore, the effect of several operating parameters including fuel flow rate, hydrogen content of COG, fuel utilization factor and operating pressure are investigated and analyzed on the proposed system performance. This research lays a good foundation for the designing of the proposed integrated SOFC-CCHP system, which would be an efficient utilization option of COG. © 2015 Elsevier Ltd.


Yang J.,Taiyuan University of Technology | Sun G.,China University of Petroleum - Beijing | Sun G.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Zhan M.,China University of Petroleum - Beijing | Zhan M.,Beijing Key Laboratory of Process Fluid Filtration and Separation
Powder Technology | Year: 2015

The separation efficiency of cyclones is closely related to the inlet velocity, and the maximum-efficiency inlet velocity (MEIV) maximizes the separation efficiency. In current separation models, particles centrifuged on the wall are considered captured, and their further motions are no longer considered. We propose that particles centrifuged on the wall impact the wall and then rebound. If the energy in these particles is sufficient, they will rebound into the upward gas flow. Within the fast upward gas flow, particles quickly move into the vortex finder and escape from the cyclone. A faster inlet velocity imparts more energy to the particles. Therefore, an excessive inlet velocity causes rebounded particles to escape, decreasing efficiency. The particle motion discussed above is the reason for the MEIV phenomenon, which is different from previous explanations. Newton's law and the hard sphere model were used to describe the particles' motion. Taken together, a new approach to forecast MEIV was established. The effects of various particle characteristics on the MEIV of cyclones, which have not been considered by previous models to forecast the MEIV, are taken into account in this new approach. We observed good consistency between the prediction of the new model and experimental data. © 2015 Elsevier B.V.


Chen J.,China University of Petroleum - Beijing | Chen J.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Gao R.,China University of Petroleum - Beijing | Liu X.,China University of Petroleum - Beijing | Li Z.,China University of Petroleum - Beijing
Huagong Xuebao/CIESC Journal | Year: 2016

Three different cyclone separators with diameter of 300 mm, PV-1, PV-2 and PV-3, were designed by changing either the direction of rotation or the diameter of vortex finder. PV-1 differed from PV-2 in the direction of rotation, while PV-3 differed from PV-1 in the diameter of vortex finder. These cyclone separators were assembled center-symmetrically in three paralleled arrangements as assembly of same cyclones (Parallel-I), assembly of various rotation (Parallel-II) and assembly of various vortex finder (Parallel-III). Parallel-I was consisted of four PV-1 cell cyclones; Parallel-II was consisted of two PV-1 cyclones and two PV-2 cyclones; Parallel-III was consisted of two PV-1 cyclones and two PV-3 cyclones. Separation performances of single cyclone and cyclone assemblies were studied in a cold state experimental setup under a condition of solid loading at 5 g·m-3 and inlet velocities ranging from 14-26 m·s-1. The flow fields in these paralleled cyclones were simulated with FLUENT software. The results show that paralleled cyclones had higher efficiency than single one with no hump in the curve of efficiency versus inlet velocity. Compared to Parallel-I, Parallel-II was lower in both total pressure drop and efficiency due to weaker swirl flow. Gas throughput was evenly distributed among each cell cyclone and no cross flow was observed in the common dust bin of either Parallel-I or Parallel-II. However, Parallel-III had higher total pressure drop than Parallel-I. Because Parallel-III was composed of cell cyclones with different vortex finder, gas throughput in Parallel-III was no longer evenly distributed and an average deviation of about 6.0% was observed between the inlet and outlet of each cell cyclone. A cross flow in the common dust bin was also happened from PV-3 to PV-1, which forced some collected particles back to the inner flow, weakened the stability of vortex flow and decreased separation efficiency. Therefore, the same type of cyclone separators should be assembled center-symmetrically in parallel in order to ensure high separation efficiency of paralleled cyclones. © All Right Reserved.


Gu X.,China University of Petroleum - Beijing | Gu X.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Song J.,China University of Petroleum - Beijing | Song J.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Wei Y.,China University of Petroleum - Beijing
Powder Technology | Year: 2016

In order to get further insight into the dynamic property of the vortex, pressure signals at various axial, radial and circumferential positions in a gas-solid cyclone were measured by multi-input dynamic pressure transducer. By adopting probability density function, standard deviation, and power spectral density methods, the characteristics of the pressure signals were analyzed and discussed. Experimental results show that there are two dominant frequencies (about 71 Hz and 179 Hz) of the pressure fluctuation in the gas flow: the former (about 71 Hz) is related to the quasi-forced vortex rotation; the latter (about 179 Hz) is related to the swing of the quasi-forced vortex core. The particle strands motion in the gas-solid flow reduces the dispersion of pressure fluctuation, mitigates the off-axis phenomenon of the core to some extent, and adds a dominant low frequency (0.31 Hz-0.86 Hz) which gets higher with the increase of inlet solids loading. The experimental results can provide insight into the pressure fluctuation in a gas-solid cyclone separator. © 2016 Elsevier B.V.


Zhang H.,China University of Petroleum - Beijing | Zhang H.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Li Z.,China University of Petroleum - Beijing | Li Z.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 2 more authors.
Energy Conversion and Management | Year: 2015

A novel electricity-heating cogeneration system (EHCS) which is equipped with an absorption heat pump (AHP) system to recover waste heat from exhaust steam of the steam turbines in coal-fired thermal power plants is proposed to reduce heating energy consumption and improve the utilization of the fossil fuels in existing CHP (Combined Heat and Power) systems. According to the first and second thermodynamic law, the changes of the performance evaluation indicators are analyzed, and exergy analyses for key components of the system are carried out as well as changes of exergy indexes focusing on 135 MW direct air cooling units before and after modification. Compared with the conventional heating system, the output power increases by about 3.58 MW, gross coal consumption rate and total exergy loss respectively reduces by 11.50 g/kW h and 4.649 MW, while the total thermal and exergy efficiency increases by 1.26% and 1.45% in the EHCS when the heating load is 99,918 kJ at 75% THA condition. Meanwhile, the decrement of total exergy loss and increment of total exergy efficiency increase with the increasing of the heating load. The scheme cannot only bring great economic benefits but also save fossil resources, which has a promising market application potential. © 2015 Elsevier Ltd. All rights reserved.


Song J.,China University of Petroleum - Beijing | Song J.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Xu D.,China University of Petroleum - Beijing | Xu D.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 2 more authors.
Chemical Engineering Journal | Year: 2016

Unwanted build-up of carbonaceous deposits on RFCC equipment surface is a key process limitation to achieving the economic benefits of longer run length. This paper focuses on the carbonaceous deposition on the outer surface of vortex finder of secondary cyclone. Macroscopic features of industrial deposits are reported in detail. Extensive characterization studies such as elemental analysis, scanning electron microscopy, energy dispersive spectrometry, thermal behavior were conducted and size distribution of catalyst particles in deposits was measured. Computational fluid dynamics method was used to obtain the gas flow field around the vortex finder. The role of gas flow to the buildup of deposits was discussed. The results will provide comprehensive understanding of deposit formation and insight into the process and operation improvement. © 2016 Elsevier B.V.


Zhang H.,China University of Petroleum - Beijing | Zhang H.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Zhao H.,China University of Petroleum - Beijing | Zhao H.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 2 more authors.
Energy | Year: 2016

A new cogeneration system which integrates a solar-assisted absorption heat pump (SAAHP) into a coal-fired power plant for waste heat recovery of exhausted steam from a steam turbine is presented to improve utilization efficiency of fossil fuels. This study compares the performances of three cogeneration systems which differ in their driving heat source of AHP in the heating system. The following cogeneration systems are considered: conventional cogeneration system (CCS), cogeneration system with AHP driven by extracted steam (CSAES) and cogeneration system with AHP driven by solar (CSAS). Compared with the CCS and CSAES, output power respectively increases by about 11.43 and 6.48 MW; coal consumption rate reduces by 26.27 and 14.29 g/kWh in the CSAS with 11529 kJ heating capacity at 100% THA (Turbine heat acceptance) condition. The integral thermal and exergy efficiency of the CSAS are 58.32% and 36.26%. Meanwhile, reduced coal consumption rate and increased power both increase with increasing heating capacity. It is found that thermal efficiency and exergy efficiency for solar energy utilization both increase with the increasing load. © 2016 Elsevier Ltd


Liu Z.,China University of Petroleum - Beijing | Liu Z.,Beijing Key Laboratory of Process Fluid Filtration and Separation | Ji Z.,China University of Petroleum - Beijing | Ji Z.,Beijing Key Laboratory of Process Fluid Filtration and Separation | And 4 more authors.
Natural Gas Industry | Year: 2016

For avoiding the adverse impacts on natural gas purification process from solid particles and liquid impurities carried by wet acid gas during its transportation, a two-stage filtration unit consisting of a pre-filter and a coalescence filter is set at the front-end of de-sulfurization process. In a certain acid gas purification plant, the pressure drop of the coalescence filter cartridge did not rise so that the replacement time of the filter cartridge was impossible to be diagnosed on the basis of pressure drop. In view of this, different combinations of two-stage filter cartridges were compared by using a two-stage filtration performance evaluation system. As being revealed, the problem was induced by the fact that the capture ability of coalescence filter for sub-micron droplets was not as ideal as the expectation and both filters were not matched in the filtration performance. Thus, two improvement measures were put forward: to optimize the coalescence layers of coalescence filter cartridges and to set the hydrophobic drainage layers on the coalescing filter and adjust the structure parameters of the pre-filter cartridge to match with the improved coalescence filter cartridge. Experimental results show that the steady pressure drop of the improved coalescence filter cartridge is reduced by 75%, and the filtration efficiency reaches 99.99% for the droplets with diameter>0.3 μm. Furthermore, synchronous pressure drop evolution is also realized between the pre-filter and the coalescence filter. Field tests reveal that the liquid capturing capacity is doubled by means of the improved filtration unit and the safe operation of subsequent process can be guaranteed effectively. This study provides reference for the design of natural gas filter cartridges and the optimization of natural gas filtration systems. © 2016, Natural Gas Industry Journal Agency. All right reserved.

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