A new alternating copolymerized derivative as a cold flow improver for diesel fuel

Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.

Analysis on A Cold Flow Snowstorm in Yantai

On December 3-5,2008,a cold flow snowfall happened in Shandong Peninsula.The basic weather situation and environmental field were analyzed.The results showed that the terrain condition,water vapor's latent heat-exchange in Bo Sea,temperature differences between sea and land were very important elements in this process.

Cold Flow Experiments and Acoustic Investigation on Pressure Oscillation Induced by Flow Instability

Pressure oscillation in solid rocket motor is believed to be the results of the interaction between the flow instability and the acoustics of combustion chamber.Several reasonable and necessary hypothesizes are given to establish an equation to describe this coupling.A cold flow motor called CVS60D(corner vortex shedding 60°)was designed to study the flow-acoustic coupling based on theoretical analysis.Experimental investigations were carried out to determine the acoustics of CVS60D.Corner vortex shedding is generated at the backward facing step which is designed similar to the geometry of the motor with finocyl propellant after the burnout of its fins.A pintle was used to modify the velocity in the duct to change the frequency of vortex shedding.It is found that large amplitude pressure oscillation occurs when the pintle moves to a range of specific position,which indicates that the frequency of vortex shedding is close to one order of acoustic modes of combustion chamber.The amplitude of pressure oscillation changes as the pintle moves.

Full Cycle Cold Flow Analysis of the Effect of Twin Swirl Combustion Chamber Design in a Diesel Engine

New designs and adaptation methods are experimented to ensure compliance to ever increasing emissions and efficiency requirements of modern diesel engines. Piston head structure which influences the mixing rate and timing of the fuel within in the combustion chamber is known to enable increase in combustion efficiency and thus lower emission rates. In this paper, computation analysis of flow within a diesel engine cylinder with a twin swirl combustion chamber design throughout a full cycle is presented. The results obtained indicate that the effect of the twin swirl combustion chamber on the cold flow conditions is noteworthy and further analysis together with experiments may reveal information that may prove to be useful in further new designs.

Numerical Feasibility Study of a Wax Cold Flow Approach for Subsea Tie-In Flowlines Using a 1D Mechanistic Multiphase Flow Simulator

This work is a thermo-fluid numerical case study to investigate the size and performance of a system that eliminates needs for insulating, heating and inhibiting chemically the deposition of wax in subsea tie-in flowlines. For short, we call this type of systems “Cold Flow”. The particular system analyzed in this study consists of a reactor unit at the inlet to the flowline, where the thermal solubility of the wax-creating molecules is reduced by cooling. Subsequently, solid wax is deposited in the reactor piping and wax free crude is entering the flowline. The reactor is regenerated periodically. The reactor-pipeline system was modelled using a commercial flowline simulator, with transient, thermal, multiphase and deposition capabilities. The basic layout used was a transportation pipeline of 8 km and 6.69 in ID with a mass flow rate of 17.51 kg/s, a water cut (WC) of zero and an inlet temperature of 70°C. The wax appearance temperature (cloud point) of the crude is 22°C and the seabed temperature is 4°C. Three types of reactors have been simulated: a non-insulated pipe section, a passive cooler with a bundle of parallel pipes and an active cooler. Sensitivity analyses have been performed for all three cases varying the external convective coefficient, the reactor pipeline diameter and the WC. For a non-insulated pipeline section cooler, the required length is of the same order of magnitude as the main flowline, implying that such a solution is impractical for short flowline distances or when a compact deployment is desired. For the passive cooler case, the required length was half of that in the previous case;thus it is still significant. For the active cooler reactor, the required cooling duty was 2.2 MW. In all three cases, the pipe-flow dynamics were analyzed, and the pigging arrangement complexity has been qualitatively addressed. However, the detailed design falls out of the scope of this study.

Influence of drag laws on pressure and bed material recirculation rate in a cold flow model of an 8 MW dual fluidized bed system by means of CPFD

A cold flow model of an 8 MW dual fluidized bed （DFB） system is simulated using the commercial compu- tational particle fluid dynamics （CPFD） software package Barracuda. The DFB system comprises a bubbling bed connected to a fast fluidized bed with the bed material circulating between them. As the hydrodynam- ics in hot DFB plants are complex because of high temperatures and many chemical reaction processes, cold flow models are used. Performing numerical simulations of cold flows enables a focus on the hydro- dynamics as the chemistry and heat and mass transfer processes can be put aside. The drag law has a major influence on the hydrodynamics, and therefore its influence on pressure, particle distribution, and bed material recirculation rate is calculated using Barracuda and its results are compared with experimental results. The drag laws used were energy-minimization multiscale （EMMS）, Ganser, Turton-Levenspiel, and a combination of Wen-Yu]Ergun. Eleven operating points were chosen for that study and each was calculated with the aforementioned drag laws. The EMMS drag law best predicted the pressure and dis- tribution of the bed material in the different parts of the DFB system. For predicting the bed material recirculation rate, the Ganser drag law showed the best results. However, the drag laws often were not able to predict the experimentally found trends of the bed material recirculation rate. Indeed, the drag law significantly influences the hydrodynamic outcomes in a DFB system and must be chosen carefully to obtain meaningful simulation results. More research may enable recommendations as to which drag law is useful in simulations ofa DFB system with CPFD.

Effect of nanocomposite as pour point depressant on the cold flow properties and crystallization behavior of diesel fuel

The high effective nano-hybrid pour point depressant(PPD)has attracted extensive attention for its po-tential application in improving the cold flow properties of diesel fuel.In this paper,the nano-hybrid PPD was prepared by melt-blending method using three different alkyl chain lengths(i.e.,tetradecyl,hexade-cyl,and octodecyl)of n-alkyl methacrylate-maleic anhydride copolymers(R 1 MC-MA,R 1=C_(14),C_(16),C_(18))and SiO_(2)nanoparticles.The effect of those nano-hybrid PPDs on the cold filter plugging point(CFPP)and solidifying point(SP)depressing of diesel fuel were studied.Results indicated that nano-hybrid PPD showed much better performance on diesel fuel.The diesel fuel treated with 0.2 wt%C_(14)MC-MA/SiO_(2)nano-hybrid PPD exhibited the best depression in CFPP and SP by 6℃ and 18℃,respectively,which higher than that of single C 14 MC-MA.Viscosity-temperature curves and polarized optical microscopy were conducted to explore the performance mechanism;and results presented that nano-hybrid PPD of C_(14)MC-MA/SiO_(2)could effectively lower the low-temperature viscosity,and modify the crystallization behavior and crystal morphology of diesel.Therefore,the cold flow properties of diesel were significantly improved.

Improving cold flow properties of palm fatty acid distillate biodiesel through vacuum distillation

Palm fatty acid distillate(PFAD),a by-product of refining process of crude palm oil can be used as a potential feedstock for biodiesel production.However,the application of palm oil-based biodiesel is often hinder by its poor cold flow properties(CFP).Biodiesel fuel with poor CFP may crystallize and result in clogging of fuel lines,filters and injectors that cause engine operability problems.For that,a vacuum distillation method was designed and its feasibility and efficiency in improving the CFP was examined.A total of 13.60wt%of total saturated fatty acid methyl esters were successfully removed from the PFAD biodiesel,resulting in the improvement of the cloud point(CP),cold filter plugging point(CFPP)and pour point(PP)of PFAD biodiesel from 20℃,19℃,and 15℃to 13℃,11℃,and 9℃,respectively.It is remarkable that the improved CFPP satisfied the requirements for grade C summer biodiesel for temperate climates in EN 14212 standard.Additionally,Sarin(U FAME)empirical correlation was evaluated and it was found to have a good prediction of CFP for PFAD biodiesel,with lower than 2℃deviation.

Study on Possible Mechanism of Terrain Influence on Cold-flow Snowstorm

[Objective] The research aimed to study the possible mechanism of terrain effect on cold-flow snowstorm.[Method] By using the meso-scale numerical model(WRF),a cold-flow snowstorm weather process in Shandong Peninsula was carried out numerical simulation and terrain sensitivity contrast test.The possible reason of terrain effect on falling zone and strength of snowstorm was deeply analyzed from water vapor,thermodynamic field and so on.[Result] The mountain terrain in Shandong Peninsula had great influences on falling zone and strength of cold-flow snowstorm.The strength of snowstorm obviously increased,and the snowfall center obviously moved northward.The main reason was that terrain caused the low-level wind field convergence and vertical movement in the troposphere strengthened.Then,the spatial distribution of water vapor and snow water content in the cold-flow snowstorm process obviously changed.So,the whole snowstorm process was affected.[Conclusion] The mountain terrain in Shandong Peninsula was the important element which needed to be focused on considering in the forecast analysis of cold-flow snowstorm weather process.

Effects of a Traditional Japanese Medicine Goshajinkigan, Tokishigyakukagoshuyushokyoto on the Warm and Cold Sense Threshold and Peripheral Blood Flow

The purpose of this study was to investigate the effects of a traditional Japanese medicine Goshajinkigan (TJ-107) and Tokishigyakukagoshuyushokyoto (TJ-38) on warm sense threshold, cold sense threshold and the peripheral blood flow. 31 healthy volunteers (control group: 9people, TJ-107 group: 12 people, TJ-38group:10 people) were examined. Drugs administered 2.5 g a dose. Analysis was before and after 1 hour dosage. The warm and cold sense threshold in the thenar of the non-handedness site of these subjects was measured using a thermostimulator (Intercross-200, Intercross Co., Tokyo, Japan). The peripheral blood flow in the finger of the non-handedness site of these subjects was measured using a full-field laser perfusion imager (FLPI, Moor Instruments Ltd., England). Control: The vehicle had no significant effect on the warm sense threshold, cold sense threshold and the peripheral blood flow. TJ-107: The warm sense threshold and cold sense threshold were significantly decreased, and the reaction latency of cold sense was significantly shortening. The peripheral blood flow was significantly increased second and third finger at 115.6%, 119.3%, respectively. TJ-38: The cold sense threshold and the reaction latency of cold sense were significantly increased. The peripheral blood flow was significantly increased second and third finger with 114.3%, 112.8%, respectively. These results suggest that TJ-107 and TJ-38 have effects on the changed warm sense threshold, cold sense threshold and increased peripheral blood flow.

Cold-state Experimental Study on Flow Characteristics of Multi-nozzle in Natural Gas Reburning Burner

Based on the prototypes of a 130 t/h boiler, constant proportional cold-state test bench is established, flow characteristics of multi-nozzle in natural gas reburning burner and its influence on the covering effect for the upflow in the furnace are researched. Numerical simulations of this process are also made with standard ?turbulence model. The results show that air flow fullness in furnace is better in the case of the reburning zone with 8 nozzles compared to 4 nozzles and also coverage effect of the reburning flow for the updraft gas in the furnace is better. In the condition each nozzle airflow velocity is constant, the effect of reburning flow on coverage of up-secondary air is best when the incident angle for four corners is 14.17?, while Center of the furnace wall is 84.57. And while the best incident angle is invariable, the effect of reburning flow on coverage of up-secondary air is best when the speed of reburning gas in the corners of furnace is 51 m/s, the same to the center of the furnace wall’s.

Effects of Bacillus subtilis Var. Natto Products on Capillary Blood Flow in Healthy Subjects with Peripheral Coldness: A Double-Blind, Placebo-Controlled, Randomized Parallel Study

Purpose: NKCP®, a natto-derived dietary food supplement whose main component is bacillopeptidase F produced by Bacillus subtilis var. natto, has antithrombotic, fibrinolytic, and pressure-lowering effects, and also is suggested to improve peripheral coldness. However, existing data are based on subjective evaluations with no scientific basis about the effects on peripheral coldness. Therefore, we aimed to investigate the effectiveness of NKCP®for peripheral coldness by measuring changes in blood flow using a laser doppler rheometer and biochemical indices. Patients and Methods: This was a double-blind, randomized, controlled study of individuals aged 30 - 70 years who complained of subjective symptoms of cold hands and feet. They were randomly divided into the NKCP®group and the placebo group to receive NKCP®250 mg once daily and dextrin 250 mg as placebo once daily, respectively. The experiment lasted 8 weeks, with an intervention period of 4 weeks and a washout period of 4 weeks. Results: One-month intake of NKCP®significantly increased blood flow rate for 1 min between 4 and 5 minutes after the end of cold loading compared to that before feeding (p = 0.038). Also, analysis of the 5-minute blood flow rate before and after 4 weeks of feeding showed a significant improvement in the NKCP®group (p = 0.007), although there was no significant difference in the placebo group (p = 0.215). Furthermore, the 5-minute blood flow at 4 weeks after the end of feeding was significantly improved compared to that before feeding in the NKCP®group (p = 0.049). Therefore, the effect continued for at least 1 month after discontinuation of administration. Conclusions: It is possible that NKCP®intake effectively improves blood flow in subjects with peripheral coldness. Therefore, continuous intake of NKCP®is expected to reduce the symptoms of peripheral coldness. In the future, it needs to investigate whether the effect of increasing blood flow after ingestion of NKCP®is effective in improving the symptoms of peripheral coldness.

基于冷流推力的变微过载控制方法研究

针对地面微重力环境下的变微过载控制方法,以不同冷流压力以及二次流入射位置等因素,开展了基于冷流推力的流场仿真,分析了二次射流对主流流场影响。并研制了冷流推力系统,通过测试验证了冷流推力与总压的相互关系。并通过微重力落舱开展了1s微重力环境下的变微过载试验,结果表明通过冷流流场型面设计,以及主流、二次流压力的控制可以控制作用于内舱的推力,从而改变内舱微重力环境下的微重力水平,满足在微重力环境下的变微过载控制能力。

寒冷地区电液制动器的油液黏度-时间模型及制动特性研究

针对寒冷地区电液制动器制动力和制动力矩不足等导致水闸制动系统发生溜车问题,基于液压油Vogel黏温模型以及当地温度变化数据,构建了油液黏度随时间变化的黏度-时间模型,并基于该模型对电液制动器制动过程中油液流动特性进行了研究,然后对电液制动器制动性能进行了定量分析。结果表明:在制动过程中,电液制动器液压油压力主要分布在活塞底腔,且随着黏度增大而逐渐增大,当油液黏度为662.4 Pa·s时,压力达到1.455×10^(-3)MPa,电液制动器液压油在叶轮中心轴部位会出现涡流循环,其循环强度随着油液黏度的增加而逐渐增加;在给定工况下,该电液制动器的最小制动力为1098 N,最小制动力矩为274 N·m。而这一制动力矩已低于该电液制动器工作力矩范围,此时可以通过更换该月份黏度更小的液压油或增设预加热系统等措施来提高其制动力和制动力矩,从而实现正常制动。

Poly-Acrylic Acid Derivatives as Diesel Flow Improver for Paraffin-Based Daqing Diesel

Since the diesel products from paraffin-based Daqing crude oil showed low sensitivity to certain commercial diesel pour point depressant （PPDs） that resulted from the high content of paraffin, certain poly-acrylic acid derivatives （PADE） with-COOR, -COOH,-CONHR, and -COO-NH3^＋R groups by molecular design on the mechanics of diesel; PPDs were synthesized and evaluated as cold flow improver for Daqing 0^# diesel in this paper. The pure PADE was superior to the commercial PPDs and displayed a substantial ability of wax crystals dispersion. There was a synergistic effect among the PADE and T1804 and secondary amine. The synergism clearly improved the low temperature performance of Daqing diesel products and could reduce the cold filter plugging point of 0^# diesel by 6-7 ℃.

冷端管径对高压节流型涡流管性能影响分析

冷端管径(D_(c))是影响涡流管性能的重要因素之一,基于12 MPa的高压节流工况,以CH_(4)为计算工质,建立物理模型,改变D_(c)为36、38、40、42和44 mm。对比发现:随着D_(c)增大,冷端内旋气体温度逐渐下降,制冷效果提升;热端外旋气体温度先增加后下降,D_(c)=40 mm时制热效果最佳。反映出D_(c)与制冷效果呈正相关,但对制热效果存在最佳值。当D_(c)增大时,内旋气体总压下降幅度逐渐平缓,利于节流;在D_(c)≥40 mm时,外旋气体总压下降幅度变大,且变化不规律,节流时有损调节阀使用寿命。另外D_(c)=44 mm时,外旋气体速度变化规律异常。所以根据工况需求,可控制D_(c)尺寸来调节涡流管制冷制热效果。

山东半岛一次典型冷流暴雪的粒子谱特征分析

为深入研究山东半岛冷流暴雪微物理特征及变化,利用激光降水现象仪(OTT Parsivel)、多普勒天气雷达和常规气象观测资料,对2020年初冬山东半岛一次东北冷涡后强冷空气造成的暴雪过程的雪粒子谱特征进行了分析。结果表明:(1)本次暴雪过程中,渤海上空850 hPa温度为-16℃,大连到山东半岛为北风与偏西风的辐合,强降雪发生在对流不稳定的大气层结中。(2)降雪粒子谱呈多峰分布,强降雪过程的初始发展、稳定和消散阶段,及一个强降雪对流系统的生成发展、成熟和消散阶段,雪粒子谱均有不同。雪粒子Gamma谱三参数特征:形状因子μ在零线附近波动,斜率参数λ小于1.0 mm^(-1),lgN0为3 m-3·mm^(-1-μ)左右。(3)强降雪时,多个数浓度中心对应的雪粒子下落末速度均在1.0 m·s^(-1)以下,最大雪粒子数浓度的峰值下落末速度为0.55 m·s^(-1)。在直径1.0 mm左右时,浓度大的雪粒子的下落末速度存在峰值,其贴近未结霜雪粒子速度曲线,说明冷流降雪的多数雪粒子不易结霜,以干雪为主。雪粒子以密凇附的枝状和聚并的板状两种类型为主,两种类型雪粒子下落末速度V和粒子直径D的关系系数和指数分别为0.62和0.33及0.69和0.41,拟合关系分别为V=0.62D^(0.33)和V=0.69D^(0.41)。

基于GO-FLOW法的苹果冷链物流系统安全性评价

应用系统可靠性理论,利用GO-FLOW方法对苹果冷链物流系统进行安全性分析和风险评价,进行GO-FLOW程序运算,分析系统各环节的可靠性和故障率,找出了影响系统安全性的关键环节并提出了解决思路.

基于GO-FLOW法的荔枝冷链物流安全评价

借鉴系统可靠性工程理论,采用GO-FLOW法分析技术,建立一种评价荔枝及其他鲜活农产品物流安全风险的定量分析方法。在对荔枝冷链物流系统进行分析的基础上,建立荔枝物流系统的GO-FLOW图,并分析了其信号流、操作符和运算规则;以具体荔枝物流过程为例,进行GO运算,求出各信号流的故障率和可靠性,找出影响物流安全的关键环节和提出解决方法;指出GO-FLOW法是物流安全评价的一个有效和方便的方法。

基于冷链工艺流程的生鲜农产品供应链风险评价

为了有效控制生鲜农产品供应链风险,降低生鲜农产品安全事件发生概率和影响程度,在冷链工艺流程基础上,文章提出了一种基于三维风险分析模型的生鲜农产品供应链风险评价模型。首先,在分析现有生鲜农产品供应链风险的基础上,从冷链工艺流程视角分析生鲜农产品供应链各环节的风险,并构建生鲜农产品供应链风险评价指标体系。然后,确定生鲜农产品冷链供应链的关键风险因素。最后,结合关键风险因素,给出对应的风险控制措施,为生鲜农产品供应链风险管控提供参考。