基于夹点分析技术的常减压装置换热网络优化

常减压装置是原油深度加工的基础,同时也是炼油企业用能大户。针对国内某企业的常减压装置,应用流程模拟软件Aspen HYSYS,建立装置的换热网络模型。以加工原油性质、初馏塔、常压塔、减压塔模拟过程参数及常减压装置对产品质量的要求作为换热网络调整的基础参数,利用Aspen Pinch软件,对装置原有换热网络进行夹点分析,根据原油常减压装置内部冷、热物流特点,分析装置用能瓶颈,得出换热网络初底原油的最高理论换热终温。按照消除原换热物流跨夹点传热、中高温位热源多次合理利用、调整换热效率偏低的设备、现有设备布置变动小、投资省的原则,对换热网络进行改造优化。通过换热流程优化调整,初底油进常压加热炉温度由原来的278℃提高到288℃;降低常压炉加热负荷及燃料消耗,可节省加热炉负荷约60×10~4kcal/h,装置能耗降低约0.7kg标油/t,折合每年创造效益约126万元。     

先进过程控制在平稳常减压装置操作的应用

青岛石化3.5Mt/a常减压装置主要加工进口高酸原油,包括达连、达混、杰诺、罕戈、瓦斯科尼亚、荣重、帕兹弗洛、马林、凯撒杰等品种,由于原油性质复杂,原油换罐频繁,对常减压装置平稳操作提出了更高要求。青岛石化常减压先进过程控制系统(APC)包括4个控制器,分别是常压炉控制器、常压塔控制器、减压炉控制器、减压塔控制器。各控制器投用后,装置关键被控变量的控制更为平稳,主要操作参数的标准偏差均降低30%以上,减轻了操作人员的劳动强度,装置能耗明显降低。先进过程控制系统投用后,装置总能耗比上年同期有所下降,其中燃料气及用电量耗能下降明显,加工1t原油,燃料气消耗平均减少1.4kg,用电量平均降低0.55k W·h,全年累计可节约3640t燃料气,节省用电1430000k W·h,有效压减装置运行成本。     

基于Aspen Plus的原油蒸馏装置流程模拟及优化

常减压蒸馏是原油加工过程中的第一道工序,常减压蒸馏装置运行的优化程度对炼厂的下游加工流程及经济效益产生重要影响。以荆门石化350×104t/a常减压装置为对象,采用Aspen Plus流程模拟软件,建立了与装置实际工况相符合的三塔全流程稳态模型,利用此模型,对常减压蒸馏装置的初馏塔、常压塔和减压塔进行灵敏度分析,以最佳轻油收率和减压渣油收率为优化目标,对加热炉出口温度、塔底汽提蒸汽量、各塔中段回流量、常压渣油350℃馏出量及减压渣油500℃馏出量,以及各参数之间的关系进行研究,并以计算数据为指导,对装置操作进行如下优化:将常压炉出口温度控制在360℃,将常压塔底汽提蒸汽量控制在2.7t/h,并对常压塔各中段回流量进行调整。经过调整优化,装置每年由于燃料油消耗下降而增加的直接经济效益达299.44万元。     

洛阳石化炼油装置节能潜力分析及优化措施

对洛阳石化炼油装置节能潜力进行了分析,并针对电、蒸汽和燃料气三项节能重点制定了优化措施。节约燃料气的措施为:优化常减压换热网络;连续重整扩能消缺改造,停运制氢装置;降低加热炉排烟温度,提高加热炉整体效率;更换高活性催化剂,降低加氢反应温度。节约电的措施为:对催化裂化装置烟机及再生器旋分器进行检修改造,提高烟机效率;负荷富裕的往复式压缩机增设无级气量调节系统;更换高能耗变压器,降低无功损耗;对部分能力过剩的机泵进行节能改造。节约蒸汽的措施为:气分装置取消蒸汽;焦化装置大吹汽改用凝结水;关闭蜡油加氢装置循环氢压缩机反飞动阀;整合乙醇胺溶剂系统;优化蒸汽管网运行,停用部分蒸汽线。措施实施后,洛阳石化每年可节约燃料13705t,节约用电21786MW·h,节约蒸汽150800t,综合能耗实现57.87kg标油/t原油的目标。     

延迟焦化装置能耗分析及优化措施

克拉玛依石化公司1.5Mt/a延迟焦化装置加工原料为稠油,于2004年建成投产。装置包括电脱盐和脱钙系统、焦化系统、富气压缩吸收稳定系统三大部分,设计能耗为1798.02MJ/t原油,但2005年装置实际能耗为1967.70MJ/t原油,远超出设计值。该装置能耗构成中,燃料气占55%以上,蒸汽占34%,耗电占10%以上。减少燃料气、电耗和蒸汽消耗是降低装置能耗的关键。为此,实施如下改造措施:①对加热炉余热回收系统进行水热媒技术改造,以高压脱氧水为传热介质,实现热烟气和冷空气之间的热量交换,保证热管表面温度均匀,改造后加热炉排烟温度降至166℃,热空气入炉温度升至267℃,热效率超过90%的设计值。②优化装置操作,减少3.5MPa和1.0MPa蒸汽消耗;降低吸收稳定系统压力和解析塔底、稳定塔底温度,增加自产蒸汽量。③优化除焦操作,缩短除焦时间,为空冷器电机安装变频系统,以降低电耗。④降低焦化装置新水和循环水消耗。节能措施实施后,2009年装置能耗为1067.31MJ/t原油,比设计值降低730.71MJ/t原油,折合燃料油为21.44kg标油/t原油。     

基于运行安全的原油库存经济性分析

中国海油H炼油厂拥有2200.0×104t/a原油加工能力、260× 104m3原油储存能力,可以接卸载货量(5～28)×104t油轮的30×104t原油码头,月度加工原油品种达到10余种,所有原油通过油轮运输到港,并经过原油码头接转输至厂内罐区,不同原油品种在常减压装置实现混合加工.由于炼油厂具有连续生产,并要维持较...     

低温热在气体分馏装置上的应用

中国石化洛阳分公司气体分馏装置原设计规模为30×104t/a,采用五塔流程,2008年扩能改造后,加工能力达到65×104t/a,实际采用四塔流程,由脱丙烷塔(T501)、脱乙烷塔(T502)、丙烯塔(T503AB/CD)、脱异丁烷塔(T504)组成。装置设计能耗为56.53kg标油/t原料,2009年装置实际能耗为51.77kg标油/t原料,但与同期中国石化先进装置能耗(37.34kg标油/t原料)相比,在蒸汽和电的单耗上,尚有差距。对此,提出实施催化装置低温热与气体分馏装置深度热联合,以及气体分馏装置内部低温优化,可取消气体分馏装置能级高的蒸汽热源,用低温热替代蒸汽伴热,蒸汽作为装置备用热源,可以节约0.3MPa蒸汽10t/h,降低装置综合能耗0.9个单位。     

延迟焦化装置的能耗分析及节能优化实践

中国海油惠州炼油分公司420× 104t/a延迟焦化装置通过停用解吸塔上重沸器3.5MPa蒸汽、停用柴油汽提塔1.0MPa汽提蒸汽、降低循环比、采用先进控制(APC)提高加热炉热效率、降低高压水泵和罐区减渣原料泵电耗、提高水的回用率、加大装置处理量等工艺优化措施,装置综合能耗比设计能耗39.03kg标油/t原料降低3kg标油/t原料.为了进一步降低装置能耗,达到国内其他先进装置的能耗水平,该装置在2011年利用检修时机,通过加热炉节能改造降低排烟温度、利用柴油低温热发生0.45MPa蒸汽、焦化富气压缩机叶轮更换、焦炭塔区特阀汽封线改造等节能改造措施.加热炉热效率由89％提高至91.5％,节约3.5MPa蒸汽用量约6.5t/h,同时减少了燃料气、蒸汽和电的消耗,使装置能耗总体降低3.16kg标油/t原料.装置节能改造每年可增加4000万元的经济效益.     

流程模拟技术在镇海炼化2号常减压装置上的应用

镇海炼化600×104t/a常减压装置为研究对象,采用Aspen Plus流程模拟软件,建立了与实际工况相吻合的常减压装置稳态流程模拟模型,通过对初馏塔、常压塔、一级减压塔和二级减压塔的模拟,了解各操作参数对装置性能的影响;通过蒸馏塔模型中的气液相负荷分布和温度梯度的分布情况,加深对蒸馏操作的理解。随着重油加工工艺技术的发展,炼厂能够加工更加劣质的渣油,因此常减压装置轻油收率和总拔出率的提高,对提高原油的利用率及炼厂的经济效益极为重要。为此,重点对影响常减压装置轻油收率的关键操作参数进行灵敏度分析,优化操作,实现提高常减压装置轻油收率的目的。经过流程模拟优化后,常减压装置一级减三线蜡油350℃馏出量降低2.3mL/100mL,以一级减三线平均流量为90t/h,以及柴油和蜡油差价300元/t计算,全年可增加装置效益536.544万元。     

炼油联合装置节能减排优化措施

巴陵石化炼油联合装置以105× 104t/a MIP-CGP装置为核心,配套产品精制、气体分离及循环水、空压站等公用工程系统.该装置直接以200×104t/a常压装置的渣油为原料,具有多产高辛烷值汽油和气体烯烃的特点.针对重油催化装置高气体收率和大注汽量的工艺特点,从催化生焦理论人手,进一步分析了随着进料密度、残炭和重金属含量的增加,装置的能耗越显著,联合装置的用能优化越复杂.通过对再生器取热系统、烟气余热回收系统、蒸汽能量梯级利用、烟机系统、供风系统、加热炉燃烧器系统、高低温位热能回收以及循环水、酸性水、凝结水系统的用能分析及优化改造,充分综合利用了各类能源,减少了装置对水的消耗.炼油联合装置能耗由72.20kg标油/t原油降至61.74kg标油/t原油,吨原油取水南0,72t/t降至0.61t/t,吨原油排水由0.64t/t降至0.30t/t.     

Education and training in renewable energy sources in Serbia and Montenegro

This paper reports the status of Education and Training in Renewable Energy Sources (RES) in Serbia and Montenegro (SAM) at the end of May 2003. It was found that universities in SAM do not give diplomas in RES. RES subjects primarily solar and wind energy are taught at graduate levels. RES units are taught as a part of some classical engineering disciplines at undergraduate level especially in solar and biomass energy. Teaching is mainly at encyclopedic level and staff is mainly trained in general fields. This education may be regarded as unsatisfactory and should be expanded and intensified in future.     

石油化工节能设备及技术进展

"十二五"时期,我国工业化、城镇化进程将进一步加快,能源需求将继续快速增长。目前,我国总体能源利用效率为33%左右,比发达国家低约10个百分点。石油和化学工业总产值占全国规模工业总产值的12%,而能源消耗量则占全国能源消耗总量的15%,是节能减排的重点对象。2012年,我国原油进口量约为2.71×108t,比上年增长6.8%。在国家发改委公布的千家重点耗能企业中,石油和化工企业占1/3。做好石油化工行业的节能减排工作,一是要在新装置设计时,认真落实国家相关标准,实施节能设计,从工艺和设备上实现源头节能;二是要对现有装置,通过技术改造,实施设备更新和工艺优化,使老装置达到节能标准;三是要不断开发新技术、新工艺、新材料和新设备,不断更新节能标准,尤其是强制性标准,在新的高度上实现节能减排的良性循环。     

Unstable and stable flow boiling in parallel microchannels and in a single microchannel

A simultaneous visualization and measurement study have been carried out to investigate flow boiling instabilities of water in microchannels at various heat fluxes and mass fluxes. Two separate flow boiling experiments were conducted in eight parallel silicon microchannels (with flow interaction from neighboring channels at headers) and in a single microchannel (without flow interaction), respectively. These microchannels, at a length of 30 mm, had an identical trapezoidal cross-section with a hydraulic diameter of 186 μm. At a given heat flux and inlet water temperature, it was found that stable and unstable flow boiling regimes existed, depending on the mass flux. A flow boiling map, in terms of heat flux vs mass flux, showing stable flow boiling regime and unstable flow boiling regime is presented for parallel microchannels as well as for a single microchannel, respectively, at an inlet water temperature of 35 °C. In the stable flow boiling regime, isolated bubbles were generated and were pushed away by the incoming subcooled liquid. Two unstable flow boiling regimes, with long-period oscillation (more than 1 s) and short-period oscillation (less than 0.1 s) in temperature and pressure, were identified. The former was due to the expansion of vapor bubble from downstream while the latter was owing to the flow pattern transition from annular to mist flow. A comparison of results of flow boiling in parallel microchannels and in a single microchannel shows that flow interaction effects from neighboring channels at the headers are significant.     

2017年我国煤炭发展形势回顾及2018年展望与建议

2017年,煤炭去产能成效显著,但总体过剩态势并没有得到根本改变;全国煤炭生产和净进口均较大幅度增长,库存虽总体下降但仍较为充足,煤炭有效供给保障增强;煤炭消费也在3年连降后小幅回弹,但消费反弹的动力较弱;全年煤炭价格波澜不惊,煤炭市场基本稳定;煤炭企业经营形势进一步向好。但是,近两年煤炭企业兼并重组去产能步伐明显滞后。展望2018年,全国煤炭需求总体与2017年持平或有所下降,完成煤炭企业兼并重组去产能的目标不容乐观。建议密切跟踪市场变化,适时调整政策,创造兼并重组的机会,加快推动重点企业兼并重组,提高产业集中度和融合度,推进煤炭工业转型升级。     

Potentials and challenges in implementing feed-in tariff policy in Indonesia and the Philippines

Located in Southeast Asia, Indonesia and the Philippines are characterized by a tropical climate and high amounts of rainfall that render their high potential for hydro-power and wind energy deployment. The volcanic geography of both countries also indicates their high geothermal potential compared with that of other countries, and their high solar radiation level makes them suitable areas to establish power plants. The present study is an archival-statistical overview of the potential generation of renewable energy in Indonesia and the Philippines and the implementation of the Feed-in-tariff (FiT) policy. This research focuses on the challenges encountered by politicians and policymakers and confirms the insufficient production of energy from wind, solar, and bio-gas sources despite the potential and the attempts to deploy FiT. Results show that the role of the government in providing support to investors is not clear in both countries. In addition, inflation rates have not been calculated. However, FiT has benefitted both countries by preventing degression during the primary years.     

Thermal and water management in irrigating lands in the arid and semi-arid regions

Excess heat and scarcity of water are the two major problems, which are usually encountered in irrigating lands especially in the arid and semi-arid regions. This paper introduces a technical approach of managing agricultural lands in the arid and semi arid regions through determination of daily water requirement and amount of heat the land is being exposed at various meteorological conditions. Through setting up a mathematical model consisting of basic heat and mass transfer equations and fluid properties, daily rate of water evaporation, different modes of heat transfer such as radiation, convection and heat transfer by evaporation at a wide range relative humidities are determined. Furthermore, the analyses are performed at two different scenarios at average air velocities of 1 and 5 m/s. Our findings showed that the volume of water evaporation at relative humidity and air temperature of φ=50% and T_∞=20 °C is 22% higher than at φ=100% and T_∞=20 °C. Moreover, at a specified φ and T_∞, the total rate of heat transfer at air velocity of 5 m/s is at least 25% higher than the total rate of heat transfer at air velocity of 1 m/s.     

Numerical and experimental study of ethanol combustion and oxidation in laminar premixed flames and in jet-stirred reactor

The main objectives of this research consist in achieving both experimental and numerical studies of the combustion and oxidation of ethanol. Experimental mole fraction profiles of chemical species (stable, radical, and intermediates) were measured in three C₂H₅OH/O₂/Ar flat premixed flames stabilized at low pressure (50 mbar) and with equivalence ratios equal to 0.75, 1, and 1.25, respectively. The experimental setup used to determine the structure of one-dimensional laminar premixed flames consists of a molecular beam mass spectrometer system (MBMS) combined with electron impact ionization (EI). The oxidation of ethanol was also experimentally studied using a fused silica jet-stirred reactor (JSR). Experiments were performed in the temperature range 890–1250 K, at 1 atm, at four equivalence ratios equal to 0.25, 0.5, 1, and 2 and with an initial fuel concentration of 2000 ppm.A kinetic study was conducted in order to simulate all experimental data measured. It enabled building a kinetic mechanism by thoroughly reviewing the available literature and by taking into account specificities of the two kinds of experiments performed. Validity of the mechanism was also checked against experimental results previously published (ethanol oxidation in a JSR at 10 atm, ignition in a shock tube, combustion in premixed, partially-premixed, and non-premixed flames). This mechanism ensures a reasonably good modelling of the combustion and oxidation of ethanol over the wide range of experimental conditions investigated.     

Energy and environmental policies in China and Taiwan

Given the environmental problems, especially in developing countries, as well as new environmental laws limiting the use of fossil fuels, governments seek to replace fossil fuels with clean energies like renewable energies. The purpose of this study was to assess the development of renewable energy as well as reviewing the laws and policies of China and Taiwan in this regard. We also constructed different scenarios based on national sources, in consideration of a significant increase in the electrical power generation and a reduction in the CO₂ emission. Focus is placed on the renewable energy development and a significant reduction in the CO₂ emission. The results showed that the photovoltaic solar systems have the greatest benefits in energy production and CO₂ emission reduction in China and Taiwan. However, due to economic consideration and technical problems, there is still a long way to go.