微波加热技术在非常规油资源中的研究现状与展望

稠油、油页岩、油砂都需要通过加热的方式来开采或者提高油的品质,而微波加热则是一种高效、快速、洁净的新型加热方式,对实现非常规油资源低成本、高效率的开发具有重要意义。本文详细介绍和评述了微波加热技术在开采和处理上述三类非常规油资源中的应用。分析表明微波加热具有能量利用率高,对环境友好等特点,不仅能快速均匀地加热整个油层,而且在催化剂的作用下,可以使原油裂解和脱硫,从而提高原油的品质。总结得出研制大功率微波发生器与模拟更真实地层条件下的室内实验评价装置、开发纳米型微波添加剂、将微波加热技术与其他开采技术结合,是未来高效利用微波加热技术的发展方向。最后建议有关部门给予支持,先进行小区块的微波采油试验。     

天然气水合物微波辅助开采模拟研究

为了提高天然气水合物开采效率及能量利用率,本文采用微波加热辅助开采,并根据南海神狐海域的水合物储层物性特征,建立了天然气水合物微波加热开采数值模型,模拟分析了不同微波加热方式下天然气水合物分解速率和能量利用率的变化情况。模拟结果表明：在使用纯微波加热开采水合物时,持续微波加热能够有效提升储层平均产气速率,而缩短微波加热时间能够有效提高能量利用率;在相同加热时间下,单循环加热的平均产气速率和能量利用率都要高于双循环加热。     

微波加热技术在催化反应中的应用

本文概括了微波加热的机理,阐述了微波与碳材料的耦合效应的作用原理,综述了微波加热技术在催化反应中应用的研究进展,指出了微波技术在催化反应中的应用所面临的主要问题,并对其发展方向进行了展望,为微波加热技术在催化反应中的研究与应用提供参考。     

仿真模拟技术在微波裂解技术上的应用研究

微波加热具有加热速度快、选择性加热等优点,而电磁场分布不均会导致加热不均,这一问题制约了微波加热技术在工业中的应用。仿真模拟技术是研究微波场分布的最佳方法。综述了微波仿真的基本原理及方法,以及国内外采用仿真模拟技术对微波加热均匀性及效率进行的研究。     

微波加热技术在橡胶硫化中的应用研究

本文针对橡胶微波加热硫化所存在的问题,应用ANSYS有限元分析软件,在分析比较了传统加热硫化和微波加热硫化胶料温升特点的基础上,提出了微波间歇加热的方法。根据硫化历程,设计了间歇加热的流程图,并模拟分析了微波间歇加热硫化胶料的温度变化趋势,模拟结果显示：采用微波间歇加热硫化能有效的解决微波连续加热硫化升温过快、焦烧时间不足、胶料不能很好充满模型,以及胶料内外温差逐渐加大的问题,对实际工程具有一定的实用价值。     

微波技术在陶瓷工业中的应用展望

简要阐述了微波加热的基本原理,论述了微波加热的特点以及微波加热技术在陶瓷工业中的应用及前景。     

农产品微波干燥均匀性研究

微波干燥技术具有脱水速度快、热效率高、易于控制等特点,并且能很好地保持物料中的营养成分,兼具杀菌作用。但在农产品微波干燥过程中,干燥均匀性一直是难以解决的瓶颈问题。微波对于农产品加热具有选择性,过度加热,易出现物料边缘或尖角部分焦化、产品表面硬化和内部糊化等现象。本文以解决农产品微波干燥均匀性的问题为切入点,对目前国内外相关研究进行了较为全面的分析和归纳,为微波技术在农产品干燥中的应用提供参考。     

微波作用下天然气水合物分解的研究及应用

介绍了微波和天然气水合物的作用的国内外实验研究进展，说明了微波对天然气水合物的分解有很大的促进作用，分析了用微波加热开采天然气水合物资源、解除天然气输送、开采过程中天然气形成水合物而造成的堵塞等应用的可行性，最后展望了微波在天然气工业中的广泛应用前景。     

正交表法测定微波脱水最佳功率和加热时间值

原油乳状液是十分复杂的分散体系,原油由于产地、开采方式、温度、压力的不同,性质也差别很大。原油含水对石油储运、加工以及产品质量造成了不利的影响,对设备造成较大的危害,因此原油破乳脱水成为石油开采及加工生产中最重要的环节之一。本实验就是在已有的试验条件下,运用正交表设计试验方案,分析了微波作用功率和加热时间对微波脱水率的影响规律,研究表明,乳状液脱水率受微波功率和加热时间的影响很大,微波加热功率和加热时间存在一个最佳值,在功率为400W,加热时间为7m in时脱水效果最好。     

微波辅助加热技术在无机材料中的应用

微波辅助加热是一种比微波加热更有优势、应用更广的新型加热技术,它可以弥补纯微波加热所产生的一些问题;本文简要介绍了微波辅助加热的基本原理、特点以及目前的设备工艺,分析了微波辅助加热在无机材料中应用所存在的不足以及解决的一些方法。     

微波场强化化工分离过程研究进展

优化化工分离技术、实现化工分离过程的节能减排,一直是化工分离过程研究的热门课题。近年来,微波场强化分离过程的研究非常活跃。本文阐述了微波对物质的作用机理以及微波加热较普通加热的优势与特点;系统介绍了微波场在萃取、精馏、干燥、脱附/吸附、蒸馏和反应精馏等分离过程的强化效果和应用进展,并分析总结了微波场在这些分离过程中的强化机理,分析表明将微波应用于化工分离过程具有加热速度快、产品质量高、耗能低和易于控制等特点;同时指出微波在分离过程特别是蒸馏/蒸发和反应精馏领域研究的欠缺,提出对于微波是否对蒸馏/蒸发或反应精馏过程具有强化作用还需要大量的实验验证和相应的理论支撑;最后本文对微波在分离领域的发展作了分析与展望。     

微波加热用于活性炭的制备、再生和改性

从微波加热的应用着手,阐述了微波辐照的热效应、微波在活性炭的制备、再生和改性过程中的作用机理;指出了微波加热处理活性炭有待进一步研究的问题。     

Analysis of catalytic reaction systems under microwaves to save energy

Effects of microwaves on catalytic reaction systems are analyzed theoretically in this work. Use of microwaves is encouraged to save energy. The effects of microwave heating are analyzed theoretically by assuming that the catalyst pellet is homogeneous. The temperature and concentration profiles within the catalyst pellet were obtained by numerical simulations for the cases of microwave heating and conventional heating. In the modeling the catalyst pellet is regarded as a continuum. When a chemical reaction was conducted in a heterogeneous medium with microwave heating, the reaction rate and the yield were found to be increased compared to conventional heating under the same reaction conditions. This is due to hot spots generated by selective heating of the catalyst pellet, resulting in an increased reaction rate.     

微波加热褐铁矿的脱水反应动力学

研究了微波加热褐铁矿的脱水过程,利用SEM和XRD分析了褐铁矿脱除结晶水前后矿相的转变. 根据升温和失重变化曲线,采用微分法和积分法计算褐铁矿结晶水热分解过程的动力学参数,确定了褐铁矿在微波加热条件下脱水的反应机制. 结果表明,该矿的化学式为2Fe2O3·3H2O;在脱去结晶水后转变为赤铁矿,Fe2O3和SiO2含量增加,晶粒尺寸减小,矿相相对变纯. 褐铁矿在470~650 K内脱水反应的表观活化能为17.39~19.33 kJ/mol,低于常规加热脱水反应的活化能,说明微波加热能降低反应的活化能;且其脱水反应机理符合Maple单行法则,属于随机成核和随后生长的化学反应控制.     

Energy efficiency of a scaled-up microwave-assisted transesterification for biodiesel production

We propose a scalable and energy-efficient microwave-assisted chemical reactor for biodiesel production, which is composed of a partially modified conventional 10-L stainless steel vessel and a microwave coupler to enable an optimized microwave injection of 99% power efficiency. The microwave power applied via a waveguide can be directly injected into the reaction vessel using a coupling rod clamped to a pressured microwave window, giving convenience of scale-up of the reactor volume because a conventional microwave transparent vessel like glass is not need. Microwave-assisted transesterification of triglycerides with potassium hydroxide catalyst achieved an accelerated conversion of 95% in 5 min. The precisely measured microwave energy consumption was only 87% of the calculated heat requirement for both the reactant and the vessel. Computer simulation studies indicated that the cause of the energy efficiency for microwave heating was the relatively low temperature of the vessel due to a reverse temperature gradient, in contrast to those done with conventional hot wall heating.     

Control of microwave-generated hot spots. Part IV. Control of hot spots on a heterogeneous microwave-absorber catalyst surface by a hybrid internal/external heating method

A problem with microwave-absorbing heterogeneous catalysts (MAHCs) in non-polar solvents is resolved with a novel approach that also uses an external heating bath in combination with microwave heating. In non-polar solvents, the microwave radiation dielectrically and selectively heats only the catalyst resulting in the frequent occurrence of hot spots under these conditions. However, such hot spots can be controlled through a combined (hybrid) internal/external heating methodology (MAHS). Moreover, high temperatures can be maintained with significant energy saving. The potential benefit of MAHS has been examined by carrying out the synthesis of 4-methylbiphenyl using the Suzuki–Miyaura coupling reaction in toluene solvent in the presence of palladium catalytic particles supported on activated carbon particulates (Pd/AC). The hybrid internal/external heating method saved 65% of microwave energy and increased the chemical yield of 4-methylbiphenyl nearly twofold in comparison with a conventional microwave heating method.     

Chemical recycling of polymer composites induced by selective variable frequency microwave heating

The application of variable frequency microwave (VFM) heating to achieve rapid thermal depolymerization of polymer composites is reported for the first time. The thermal and chemical influence of composite additives on polymer decomposition has been studied for a set of chemically recyclable polymers, including polyphthalaldehyde, polypropylene carbonate, two polyhydroxyalkanoates, and nylon 6. Carbon-based additives, specifically nanocarbon particles, were used as effective microwave absorbers to controllably degrade the surrounding polymer matrix into valuable, monomeric compounds. Depolymerization and byproduct confirmation were quantified by gel permeation chromatography and nuclear magnetic resonance spectroscopy. Synergistic effects can be leveraged from pre-treating composite samples to further reduce the total microwave energy required to depolymerize composite samples. This study establishes the use of VFM heating for chemical recycling of polymer composites that can be leveraged toward a plastic circular economy.     

Recent advances in microwave initiated synthesis of nanocarbon materials

This Feature Article focuses on the recent advances in synthesis of nanostructured carbon materials using microwave irradiation as the heating source. Although the microwave approach to chemical synthesis is relatively mature in organic synthesis, it is still in the early stage for nanomaterials synthesis, especially nanocarbons. Due to the energy efficient nature of microwave heating, there is a great opportunity to apply microwave irradiation to nanocarbon production, which normally requires high temperature, high vacuum or inert gas protections. Using microwave irradiation will give a green feature to the nanocarbon synthesis, since it offers high efficiency heating and fast carbonization. With our recent discovery, multi-walled carbon nanotubes can be synthesized through the microwave process even in air. Background about nanocarbons and microwave chemistry are introduced, the application of microwaves in synthesis of different types of nanocarbons is discussed and finally, the perspectives in the future research directions of microwave assisted nanocarbon synthesis are deliberated as well.     

微波合成纳米碳化钛粉体的动力学研究

以纳米二氧化钛和碳黑为原料，用微波加热合成纳米碳化钛粉体。对微波合成纳米碳化钛的反应过程进行动力学研究。用X-射线衍射法表征合成粉体的合成率及颗粒大小。结果表明，微波合成纳米碳化钛粉体的化学反应属零级反应，且确定了反应动力学方程及反应的活化能。     

微波加热在毛条烘干中的应用研究

介绍了应用微波加热烘干毛条的基本原理,研究了微波干燥设备的烘干效率、节能效果及烘干效果,结果表明,微波加热可以应用于纺织印染行业,为微波加热在纺织印染行业的推广应用提供了研究基础。通过生产应用,在计算微波加热毛条烘干工艺参数时,微波烘干机的干燥效率可取1.1kg/kW﹒h,微波干燥后,毛条含水率均匀,颜色前后色差无变化,纤维的强度和手感得到改善,微波干燥节能效果,比射频烘干节能约20%。