煤的液化传输及稳定机理研究

发布时间：2018-05-12 17:56

本文选题：煤 + 液化传输　；参考：《西南石油大学》2017年硕士论文

【摘要】：在我国煤的短距离运输以公路运输为主,此类运输方式具有便捷、灵活、易于统筹安排等优点,自上世纪新中国成立以来延用至今。随着社会的发展和公众环境意识的提高,公路运输方式伴随的一系列缺陷也突显出来。运输中的固体废弃物和内燃机的废气排放为主要的环境污染问题,汽车作为移动的污染源具有难控制、不固定的特点,对污染的控制和治理造成了较高的技术困难。同时,以块状运输的粗犷运输方式,造成了煤大多采用固定床燃烧技术(fixed bed combustion technology)进行燃烧,而抑制了具有诸多环保和经济优点的流化床燃烧技术(fluidized bed combustion technology)的推广。因此,建立一种新型的传输技术,取代原有的公路运输具有社会必要性。研究采用水力压裂传输技术(hydraulic fracture transportation technology)相类似的方式,将煤块破碎为煤粉,与压裂用支撑剂(proppant)相似,借助具有一定粘弹性的流体对其进行输送,构建出煤的液化传输技术。为实现煤粉的流体运输,需对流体特性进行改变。根据斯托克斯重力沉降公式(Stokes sedimentation law),沉降速度受控于颗粒的粒径、流体粘度和颗粒与流体的密度差,由于煤粉密度不变,方案研究中对煤粉的粒径分布、流体的粘度和密度进行了研究,并在实验研究的基础上获得初步方案。运行方案确定了三个变量的变化范围,据此以经济成本为决策目标,煤粉悬浮性为约束条件,建立了煤液化传输技术的多目标规划数学研究方法,并借助MATLAB进行了最优化问题的求解,运行结果为:煤粉80-100目,流体密度p=1.15g/cm3,用于提升流体粘度的黄原胶质量分数ω=0.35%;煤粉100-120目,流体密度p=1.15g/cm3,用于提升流体粘度的黄原胶质量分数ω=0.25%;最佳液化传输方案为100-120目煤粉对应方案。正文中详细给出了编辑程序语言的代码和运行图。表面活性剂(surfactant)对煤粉在液相中稳定性影响研究结果显示,离子型表面活性剂能延长煤粉的沉降时间,其原因在于表面活性剂亲油基团吸附于煤粉表面,带电的亲水基团分布在煤粉表面而形成双电层结构,增强了煤粉的稳定性。实验结果显示以十二烷基苯磺酸钠(sodium dodecyl benzene sulfonate,SDBS)为代表的抗钙阴离子表面活性剂对煤粉稳定性具有增强作用,但在方案应用中不具有经济价值。温度对煤粉稳定性的影响原因在于对黄原胶溶液粘度的影响,黄原胶粘温曲线显示随着温度的升高,溶液粘度逐渐下降,因此较低的环境温度更利于煤的稳定和传输。液化传输的流体在经氧化降粘后体系内的煤粉迅速沉淀,实验研究的降粘剂及使用浓度为1000mg/L的过氧化氢(hydrogenperoxide,H2O2),氧化产出液粘度降低至2mPa·s,该产出液可重复用于配制传输煤粉的流体。本文以油田水力压裂支撑剂传输技术为思路,建立了液体传输煤粉的新型传输技术。实验研究中对该传输技术进行了方案的合计及优化,数学问题的计算机求解取得了更为精确的优化方案。该运输方案解决了过去公路传输方案中存在的环境问题,方案的特性将促进流化床燃烧的应用,对清洁生产具有重要意义。
[Abstract]:The short distance transportation of coal in our country is mainly by highway transportation. This kind of transportation has the advantages of convenient, flexible and easy to plan. Since the founding of new China in the last century, it has been used since the founding of new China in the last century. With the development of the society and the improvement of public awareness of the environment, a series of defects accompanied by the way of highway transportation are also highlighted. As the main environmental pollution problem, the vehicle as the main source of environmental pollution is difficult to control, and the unfixed characteristics of the vehicle have caused high technical difficulties for the control and control of pollution. At the same time, the rough transportation of lump transportation causes the coal to use the fixed bed combustion technology (fixed bed combustion Tech). Nology) burning, and restraining the popularization of fluidized bed combustion technology with many advantages of environmental protection and economy. Therefore, it is necessary to establish a new type of transmission technology to replace the social necessity of the original road transport. The study adopts the technology of hydraulic fracturing transmission (hydraulic fracture transportation TE). Chnology) in a similar manner, coal is broken into pulverized coal and similar to the fracturing proppant (proppant). With the aid of a fluid with a certain viscoelasticity, the coal liquefaction transmission technology is constructed. In order to realize the fluid transportation of coal powder, the fluid characteristics need to be changed. According to the Stokes gravity settlement formula (Stokes sedimentation) Law), the velocity of settlement is controlled by particle size, fluid viscosity and the density of particles and fluid. Due to the constant density of coal powder, the particle size distribution of pulverized coal, the viscosity and density of the fluid are studied in the scheme study, and a preliminary scheme is obtained on the basis of the experimental study. The operation scheme determines the range of change of the three variables. Accordingly, the variation range of the coal powder is determined. The economic cost is the decision target and the pulverized coal suspension is the constraint condition. The multi-objective programming mathematical research method of coal liquefaction transmission technology is established, and the optimization problem is solved with the help of MATLAB. The operation results are as follows: 80-100 mesh of coal powder and p=1.15g/cm3 of fluid density, used for the xanthan mass fraction =0.35% of the xanthan glue to lift the viscosity of the fluid, and 100-1 of the coal powder. 20 mesh, the fluid density p=1.15g/cm3, used to improve the fluid viscosity of the xanthan mass fraction of the mass fraction of Omega =0.25%; the best liquefaction transmission scheme is the 100-120 mesh pulverized coal corresponding scheme. In the text, the code and operation diagram of the editing program language are given in detail. The effect of the surface active agent (surfactant) on the stability of the pulverized coal in the liquid phase shows that the ionic type is an ionic type. The surface active agent can prolong the settling time of the pulverized coal. The reason is that the surface active agent is adsorbed on the surface of the coal powder. The charged hydrophilic group is distributed on the surface of the pulverized coal to form a double layer structure and enhances the stability of the pulverized coal. The experimental results show that the sodium dodecyl benzene sulfonate (SDBS) is the representative of the Sodium Alkylbenzene Sulfonic Acid (SDBS). The anti calcium anion surfactant has an enhanced effect on the stability of pulverized coal, but it is not of economic value in the application of the scheme. The influence of temperature on the stability of pulverized coal is the effect of the viscosity of the xanthan gum solution. The viscosity of the xanthan adhesive temperature curve shows that the viscosity of the solution decreases gradually with the increase of temperature, so the lower environmental temperature is more beneficial. The coal powder is stable and transmitted. The liquid of liquefied transport is precipitated rapidly in the system of oxidation and viscosity reduction. The viscosity reducer and the hydrogen peroxide (hydrogenperoxide, H2O2) used in the experimental study are 1000mg/L, and the viscosity of the oxidized output liquid is reduced to 2mPa. S. The liquid can be reused to prepare the fluid for transporting pulverized coal. The new transmission technology of liquid pulverized coal is established. In the experimental study, the scheme of the transmission technology is combined and optimized. The computer solution of mathematical problems is more accurate. The transportation scheme solves the environmental problems in the highway transmission scheme. The characteristics of the case will promote the application of fluidized bed combustion, which is of great significance for cleaner production.

【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD56

【参考文献】