我国油田伴生气回收与利用技术状况分析

在介绍我国伴生气资源量等情况基础上,重点评述井站套管气回收和联合站轻烃回收的主要工艺和方式,包括多种集气技术、燃烧利用、发电、冷油吸收、低温法、膜法等,分析了多种技术的适用条件和局限性。指出国内当前伴生气利用存在的主要问题,如气量计量和预测问题、边远小气量伴生气利用难度大问题等。提倡遵循"因地制宜"、"分级利用"的原则,避免伴生气资源的浪费,避免造成优质能源的低级利用;着力解决我国伴生气利用领域密闭集输不完全、经济性较差、高质低用等欠佳状况。最后介绍了国内塔里木油田、长庆油田伴生气利用方面的新进展和案例,并提出亟待进一步提高伴生气商品率、降低设备能耗、建立相应测量规范与标准等建议。

Determination of volatile components in cut tobacco with gas chromatography-mass spectrometry and chemometric resolution

Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation and extraction method,the volatile components in cut tobacco were detected by GC-MS.Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms.The qualitative analysis was performed by similarity searches in the national institute of standards and technology(NIST)mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response.The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra.107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified,accounting for about 88.01% of the total content.The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.

Calculation of stratosphere–troposphere exchange in East Asia cut-off lows:cases from the Lagrangian perspective

In this study,the authors focus on the cut-off low pressure systems（COLs）lingering over East Asia in late spring and early summer and quantify the two-way stratosphere–troposphere exchange（STE）by 3D trajectory integrations,achieved using a revised version of the UK Universities Global Atmospheric Modelling Programme Offline Trajectory Code（Version 3）.By selecting 10 typical COLs and calculating the cross-tropopause air mass fluxes,it is found that stratosphere-to-troposphere transport（STT）fluxes exist in the center of COLs;and in the periphery of the COL center,troposphereto-stratosphere transport（TST）fluxes and STT fluxes are distributed alternately.Net transport fluxes in COLs are from stratosphere to troposphere,and the magnitude is about 10-4 kg m-2 s-1.The ratio between the area-averaged STT and TST fluxes increases with increasing strength of the COLs.By adopting appropriate residence time,the spurious transports are effectively excluded.Finally,the authors compare the results with previous studies,and find that the cross-tropopause fluxes（CTFs）induced by COLs are about one to two orders of magnitude larger than global CTFs.COLs play a significant role in local,rapid air mass exchanges,although they may only be responsible for a fraction of the total STE.

Assessment of the Influence of Torrefied Biomass Physical Characteristics, Design and Operating Variables on Gasification Efficiency

Gasification efficiency is an important factor that determines the actual technical operation as well as the economic viability of using a gasifier system for energy production. In this study, the impact of the physical properties of torrefied bagasse and the influence of gasifier design and operating variables were investigated in a computer simulated downdraft gasification system. Results obtained from the study indicated an interrelationship between feedstock characteristics, especially with regard to feed size, design variables such as throat angle and throat diameter as well as gasifier operating conditions such as temperature of input air and feed input. These variables influenced the efficiency of the gasification process of sugarcane bagasse because of increased enhancement of combustion zone reactions, which liberated huge amount of heat that led to a rise in the temperature of the gasification process. This condition also created increased tar cracking within the gasification system, contributing to reduction in the overall yield of tar.

Constructal design for a steam generator based on entransy dissipation extremum principle

Steam generator is optimized by applying entransy dissipation extremum principle and constructal theory and adopting analyti-cal method.The obtained results show that the optimal spacing between adjacent tubes,the mass flow rate of gas and the maximum entransy dissipation rate all depend on the dimensionless diameter of one tube,the dimensionless pressure difference number and the dimensionless length of flow channel of gas.Besides the three dimensionless groups,the optimal numbers of riser tubes and downcomer tubes and their summation all depend on the dimensionless height of one tube.The maximum entransy dissipation rate increases as the pressure difference that drives the gas flowing increases,and as the diameter of one tube and the length of flow channel both decrease.The mean heat flux in the heat transfer process of hot gas grows greatly,and the performance of the system is improved.Compared with the optimal construct with heat transfer rate maximization,the optimal construct with entransy dissipation rate maximization can improved the heat transfer effect of the steam generator more.

低压油田气集输及轻烃回收工艺探讨

迈入21世纪以来,随着国内经济和科学技术的快速发展,国家对能源的利用需求也不断增加,根据相关统计数据显示,国家对进口油气的消费量占总量的一半还多,针对此类情况,国家对国内各大石油公司进行大规模的管理创新,要求石油公司依靠先进的科学技术自立和持续创新,以此增加勘探开发的投资力度,使国内油气总量得以持续稳定增长。因此,加强对低压油田气集输和轻烃回收工艺的利用,可以进一步降低国家对不可再生能源的损耗,从而提高国家经济健康、稳定的持续发展。