基于超声波技术优选最佳油田管道除垢参数

目前,我国仍有八成以上的原油需要管道来输送,而管道长期运行过程中难免会有蜡晶析出,蜡晶析出后如不及时清理就会变成污垢附着在管道内壁。油田管道的结垢问题已经严重影响到输油工作的正常进行,超声波除垢技术作为一种新型的绿色环保技术越来越受到青睐。为了优选对比出超声波对油田管道除垢效果达到最佳的频率,设计了一套模拟超声波对输油管道的除垢装置,模拟不同频率以及不同时间下的超声波除垢效果实验。通过实验数据的对比分析,发现超声波频率在48kHz,作用时间为5min时除垢效果最佳。     

超声波防、除垢技术在石化企业上的应用

介绍了几种不同的除垢方法,比较了各种防、除垢方法的利弊,重点介绍了超声波防、除垢机理。通过在石化企业换热器上的使用案例资料,有效地证实了超声波防、除垢技术的防、除垢效果明显,解决了换热设备的结垢问题,同时节能效果显著。     

磁化除垢影响因素作用规律及其数学模型研究

在交变磁场作用下对碳酸钙进行除垢的影响因素较多，为研究磁场条件下不同工艺因素对碳酸钙结垢的影响规律，研究采用正交方法对饱和碳酸钙溶液进行了磁化试验处理，结果表明：磁化时间和初始钙离子浓度为影响磁化除垢的最显著因素，当磁化时间为0.5 h、电流频率为0.6 kHz、线圈匝数为100圈、c₀（Ca²⁺）为1 000 mg/L、波形为方波时，该条件下磁化溶液的电导率平均值为1.474 mS/cm，与未磁化碳酸钙溶液相比，其电导率增加了0.147 mS/cm，电导率可增加11.45个百分点，除垢效果良好。研究通过回归分析方法建立的磁化除垢作用规律数学模型，可为提高管路的磁化除垢效率提供一定的理论依据，也对工业冷却水系统的除垢问题有重要的参考意义。     

静态实验研究超声波对碳酸钙结垢影响规律

随着油田的开采,结垢问题已经严重影响到油田的正常生产秩序,增加了油田的生产成本。超声波除垢是利用超声波强声场处理流体,使流体中成垢物质分散、粉碎、松散、松脱而不易附着管壁形成积垢。用静态实验法研究管壁材质、超声波功率、超声波频率、溶液p H值对碳酸钙结垢影响规律发现:超声波对铜管的抑垢效果比对不锈钢管要好;一定范围内提高声强,除垢效果变好;不同频率的超声波对碳酸钙结晶形貌的影响不同; p H会影响超声波抑垢率,偏酸偏碱溶液都会促进垢的形成,降低超声波的作用。     

超声波除碳酸钙垢的实验研究

目前,超声波是一种在工业中广泛应用的技术,可以用于油田管道的污垢清理。为了更加深入研究超声波除碳酸钙垢的效果,有必要探究超声波的参数对除垢率的影响。在实验室条件下,组装了一套超声波除垢设备,通过改变超声波的频率、辐照时间和辐照温度,分别处理Q235钢制挂片上的碳酸钙垢,采用处理前和处理后挂片质量差的方法来评价除垢效果。实验结果表明在频率为28 kHz、辐照时间为10 min和辐照温度为40℃的条件下,超声波除碳酸钙垢能力强、效果好。因此,优选出超声波不同参数之间的组合对提高除碳酸钙垢率至关重要。     

基于正交试验的交变磁场除垢影响因素作用规律

为优化磁化除垢条件,进而提高磁化除垢效果,采用正交试验方法对饱和碳酸钙溶液进行磁化试验,并对磁化除垢效果进行表征。结果表明:初始钙离子浓度和电流频率为影响磁化效果的显著因素,磁化时间、线圈匝数和波形为不显著因素。磁化除垢的最优条件:初始钙离子为1 000 mg/L,频率为0.9 kHz,磁化时间为0.5 h,线圈匝数为150圈,波形为方波。     

环己酮装置超声波防除垢节能技术开发及应用

针对环己烷液相氧化法生产环己酮工艺过程中环己烷精馏塔再沸器易结垢的问题,分析了环己烷精馏塔再沸器的结垢原因和结垢对环己烷精馏塔再沸器的影响。为解决传统的化学和物理除垢技术的缺点,开发了超声波防除垢节能技术。该技术在60 kt/a环己酮装置进行了应用,结果表明:环己烷精馏系统运行周期由3个月延长至9个月以上,烷塔再沸器传热效率提高13.32%,每吨环己酮产品原料苯的消耗降低5 kg以上。该技术的开发和应用有效解决了环己烷精馏塔再沸器易结垢的问题,节能降耗效果显著,并且减少了装置停车损失和频繁开停车带来的安全环保风险。     

换热器防垢除垢实验研究

考察了二甲基甲酰胺中的盐在换热器换热冷却过程中的结垢行为,分别采用内置弹簧和液固流态化以及两者结合的方法对换热器在线防垢除垢进行研究.采用测定总传热系数法研究污垢热阻随时间的变化规律,并用污垢称重法测定不同条件的总污垢量.研究了流体流速、传热温差、弹簧结构、惰性固体颗粒数量和大小等诸因素对结垢的影响,结果表明:直径与管内径比为0.8,螺距和管内径比为1.5的弹簧在0.6～1.0 m-s-1的流速范围内防垢除垢效果最佳,随着颗粒数量的增加和粒径的增大,污垢生成速率降低,结垢量减少,相比同条件下单纯颗粒流态化除垢,内置弹簧和颗粒流态化结合法可以使污垢量减少20%～50%.实验研究结果对实际的工业过程具有一定的参考意义和指导价值.     

超声波防除垢技术在乙烯装置上的应用

茂名石化乙烯装置低压脱丙烷塔再沸器结垢问题严重,污垢成分以管程聚合物为主,长期以来缺乏有效的防垢技术措施,制约装置的经济运行。分析了茂名石化乙烯装置低压脱丙烷塔再沸器结垢原因,采用超声波防除垢技术对该设备进行了技术改造,运行结果表明超声波防除垢技术有效延长了再沸器的运行周期,节省了其蒸汽用量,达到了节能增效的目的。     

超声波辅助法在输油管道除垢、防垢中的应用

以输油管道垢块、金属铁片为研究对象,利用化学试剂、化学试剂与超声波相结合的方法分别对其进行除垢、防垢实验。结果表明,选用10%Na2CO3,10%盐酸,0.5%NaF组成的除垢剂,除垢量可达0.013 1 g/m2,和超声协同作用除垢量可达0.075 9 g/m2;选用0.01%NaOH、0.01%Na3PO4组成的防垢剂防垢,经过1 h,结垢量为6.83 g/m2,而与超声配合使用,经过同样的时间,结垢量为0.25 g/m2,防垢率可达96.3%。该研究说明了超声波对输油管道具有较强的除垢、防垢能力。     

Determination of the effect of the ultrasonic frequency on the cooling crystallization of paracetamol

This paper presents a study on the effect of ultrasonic frequency on both the nucleation and the degradation of paracetamol under sonication. The effect of ultrasonic irradiation was investigated for frequencies ranging from 41 to 1140 kHz. The results obtained in this paper show that the lower ultrasonic frequencies are preferable, both to enhance the nucleation rate and to limit degradation. A reduction of the metastable zone width was observed in all experiments when applying ultrasound. The highest reduction was achieved at a frequency of 41 kHz and a decrease of the reduction was observed with increasing ultrasonic frequencies. Degradation was limited at a frequency of 41 kHz, while significantly higher levels of degradation are observed at higher frequencies. Radical formation seems to be the main degradation mechanism for all frequencies.     

Intermittent ultrasound-assisted ceramic membrane fouling control in ultrafiltration

In this study, remediation of ceramic membrane fouling by an in-line intermittent ultrasound system was investigated. A piezoelectric ultrasonic transducer was integrated into a membrane unit that provided ultrafiltration (UF) of a diluted skim milk solution containing 0.10 wt% of protein. The effects of ultrasound at varied frequencies (20, 28, and 40 kHz) and power intensities (1.44, 2.88, and 5.76 W/cm²) under continuous operation and intermittent mode at various intervals (0.50, 1.0, 1.5, 2.0, 2.5, and 3.0 minutes) on membrane fouling were studied. The quality and flow rate of the permeate stream were monitored for the evaluation of the UF process performance. Optimal conditions of continuous ultrasound were found at 28 kHz and 2.88 W/cm². Moreover, at optimal ultrasonic conditions, the optimal intermittent time was found at 0.50 minute. At optimal ultrasonic conditions, the permeate amount increased by 79.8% and 94.2% for 0.50 minute intermittent ultrasound and continuous ultrasound, respectively, as compared with that of the UF process without ultrasound. Also, intermittent ultrasound induced better fouling control at a lower protein concentration of 0.05% by weight. The cleaning effect of ultrasound could be attributed to the cavitation bubbles generated by the rarefaction and pressure cycles of the applied ultrasound.     

Single-layer graphene sound-emitting devices: experiments and modeling

Single-layer graphene (SLG) was demonstrated to emit sound. The sound emission from SLG had a significant flat frequency response in the wide ultrasound range from 20 kHz to 50 kHz. SLG can produce a sound pressure level (SPL) as high as 95 dB at a distance of 5 cm with a sound frequency of 20 kHz. The SPL value is among the highest reported to date for sound-emitting devices (SEDs) based on the thermoacoustic effect. A theoretical model was established to analyze the sound emission from SLG. The theoretical results are in good agreement with the experimental results. Conventional acoustic devices with a large size can be reduced to the nano-scale by using this novel SLG-SED material. It has the potential to be widely used in speakers, buzzers, earphones, ultrasonic transducer, etc.     

Agglomeration and demulsification of emulsions by ultrasound

以水为连续相、二氯乙烷为分散相,配制成稳定的乳状液,在超声驻波场条件下,对其进行凝聚破乳研究,重点考察超声声强、超声辐照时间、沉降时间、超声作用频率对乳状液破乳的影响。结果表明,超声声强的改变直接影响了乳状液分散相液滴的凝聚和发散,超声破乳的声强应在临界阈值以下;超声辐照时间存在一个最佳作用时间;超声频率对液滴凝聚有重要影响,根据体系黏度、密度、液滴粒径等性质计算了最佳超声凝聚频率,并通过了实验验证。设计了正交实验,综合考虑了能耗和破乳效率,得到该乳状液破乳最佳条件为：超声频率10 kHz、声强270 W•m^-2、辐照时间9 min、沉降温度40℃及沉降时间3 h。此条件下,其破乳率可达到91%。     

Experimental investigation on proper use of dual high-low frequency ultrasound waves—Advantage and disadvantage

An experimental study was conducted to investigate the proper use of dual frequency ultrasound irradiation in sonoreactors. For this purpose, two waves with frequencies of 1.7 MHz and 24 kHz were combined. A dual frequency rig was equipped with a high frequency 1.7 MHz ultrasound transducer and a low frequency one generating 24 kHz waves. Dushman competitive reactions were used to study micromixing, Weissler reaction for evaluating cavitation activity and ammonia degradation experiment to investigate the superposition effect of two coupling waves on decomposition strength. The results revealed that combining these waves has a positive effect on number of generating cavitation bubbles and micromixing performance. However, this combination reduced the strength of the low frequency wave and diminished the ammonia degradation process efficiency. The micromixing enhancement in terms of the segregation index in dual frequency irradiation mode is approximately 46.9% and 40.1% more than single low and high frequency irradiation, respectively. On the other hand, the ammonia removal efficiency is reduced by 10.3% in dual frequency irradiation compared to single low frequency layout.     

超声对合成乙酸正丁酯的影响因素研究

酯化反应是一种常见的有机化学反应,合成的有机酯类被广泛地用作香料,染料和溶剂等。本文在室温下,以浓硫酸为催化剂,考察了有无超声、超声频率、超声声强和氮气通气量等参数对催化合成乙酸正丁酯的影响。实验结果表明,超声在室温下辅助合成乙酸正丁酯也有很好的效果,一系列最优化参数如下:单频条件下,声频率10kHz,输出电压200V,空气通气量0.4L/min;混频条件下,声频率10kHz和30kHz正交辐照,输出电压200V,氮气通气量0.4L/min。     

Composite Polymers Transducers for Ultrasonic and Biological Applications

Ferrite polymer transducer and copolyesters are being used for ultrasonic generation to be used in technology and in biological applications like orthodontic treatment. The objectives of this study were to introduce a new piezoelectric composite polymers and to evaluate and compare their electric and mechanical properties with the widely used other materials. The resonance and antiresonance frequencies were measured for the materials in the radial mode. It is noticed that the resonance frequency decreased with increasing CoZn ferrite concentrations in polymers. The electromechanical coupling factor was determined to be of value 0.8 which is the highest value of the piezoelectric materials. It is very difficult to produce ceramic transducers in large sizes because they are fragile, thus the composite transducer could be an alternative. The ultrasonic wave velocity of the composite polymer is higher than that of other polymers and piezoelectric ceramics making them more attractive for many applications than ceramics. The Young's modulus of the composite polymer increased with increasing ferrite concentrations.     

超声协同交联β -环糊精处理苯酚废水

环糊精因其特殊的结构特点,尤其是经过交联剂改性的交联β-环糊精（MDI-β-CD）,可以处理与其空腔尺寸匹配的苯酚污染物,具有更好的处理苯酚废水的能力。为进一步提高MDI-β-CD处理苯酚废水的效果,研究其在超声协同条件下的废水处理能力和适合工况。通过对MDI-β-CD用量、废水pH值、废水浓度、超声声强和频率的研究,找到处理苯酚废水的适合工艺条件：超声频率20 kHz,超声声强0.2 W/cm2,苯酚初始浓度100 mg/L,pH值6.0,溶液体积100 mL,反应温度40 ℃,吸附时间120 min,MDI-β-CD用量40 g/L;在此条件下,MDI-β-CD与超声协同处理苯酚废水吸附效率可以达到94.1%。