酮麝香、二甲苯麝香和1,3-二甲基-2,4-二硝基-5-叔丁基苯固-液相平衡研究

The solid-liquid equilibria of musk ketone musk xylene, musk xylene 1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are measured by differential scanning calorimeter (DSC), these systems are proved to be simple eutectics. Moreover the melting points and the fusion enthalpies of musk ketone, musk xylene and 1,3-dimethyl-2,4-dinitro-5-tert-butyl benzene are also measured by the DSC. These solid-liquid equilibrium data and the heats of fusion are reported for the first time. Then UNIFAC model is used to correlate the solid-liquid equilibrium data.It is shown that the solid-liquid equilibria of musk systems can be predicted bv the UNIFAC model.     

酮麝香-二甲苯麝香双液相萃取结晶

To evaluate the effect of two liquid phase on the separation of musks mixture, the phase equilibria of musk ketone musk xylene dimethyl sulfoxide heptane system were studied for the first time. The whole and every part of the phase equilibrium for the quaternary system were shown by three-dimensional phase diagrams, the liquid-liquid equilibria, solid-liquid equilibria and solid-liquid-liquid equilibria of the quaternary system were also shown. As a result, the compositions of musks in the equilibrium liquid phases were different from those in the feed, that is, musk ketone was enriched in dimethyl sulfoxide phase while musk xylene was enriched in heptane phase. So these equilibrium liquid phases were useful in separating musk ketone and musk xylene. On the basis of these results, a new process “two liquid phase extractive crystallization” was proposed to separate the eutectics of musk ketone and musk xylene.     

Separation of As and Bi and enrichment of As,Cu, and Zn from copper dust using an oxidation-leaching approach

Copper dust with high arsenic content is a hazardous waste that should be treated properly. Herein, the copper dust is oxidized, leached, and separated at room temperature and atmospheric pressure. To separate As and Bi, part of As(Ⅲ) in copper dust is oxidized to As(V), so that most of the As, Cu, and Zn elements enter the solution and the Bi remains in the leaching residue. Also, the influence of several factors,such as H_2 SO_4 dosage, H_2 O_2 dosage, liquid–solid ratio, leaching temperature and leaching time, on the leaching percentage of As, Bi, Cu, and Zn is systematically investigated. The optimal conditions are obtained as follows: liquid–solid ratio of 3:1, H_2 O_2 dosage of 10 ml/50 g(dust), H_2 SO_4 dosage of4.5 ml/50 g(dust), leaching temperature of 85 °C, and leaching time of 3 h. Under these conditions,the leaching percentage of As, Cu, Zn, and Bi is found to be 97.39%, 96.11%, 97.32%, and 2.40%, respectively. For further recovery of As from the leaching solution, the one-step recycle leaching of the leaching solution is performed to increase the concentration of As in the recycled leaching solution. The concentration of arsenic in the recycling leaching solution is found to be 79.63 g·L~(–1), which is beneficial for the study on further recovery of As_2 O_3.     

Mathematical model of absorption and hybrid heat pump

Recovering waste heat from industrial processes is beneficial in order to reduce the primary energy demands and heat pumps can be used to this purpose.Absorption heat pumps are energy-saving and environment-friendly because use working fluids that do not cause ozone depletion and can reduce the global warming emissions.The hybrid heat pump processes combine the conventional vapor-compression and the absorption heat pump cycles.Studies about the simulations and modeling of hybrid heat pumps are few in literature.In this research a mathematical model for single effect absorption and hybrid heat pump is carried out with ChemCad(R) 6.0.1.LiBr-H2O is used as working fluid while electrolytic NRTL and electrolytes latent heat are used as thermodynamic model due to the better results.Binary parameters of activity coefficients are regressed from experimental vapor pressure data while default constants are used for the solubility expressions.A design of heat pumps is developed and a new modeling of generator is analyzed.The coefficient of performance of absorption heat pump and hybrid heat pump is equal to 0.7 and 0.83 respectively.For absorption heat pump a sensitivity analysis is carried out to evaluate the effect of temperature and pressure generator,the concentration of Li-Br solution on coefficient of performance,cooling capacity and working fluid temperature.For hybrid heat pump,the different coefficients of performance,the primary energy ratio,the generator heat,and the compressor power are analyzed for different values of compressor proportion.Results show that comparing the two systems the hybrid pump allows to save more primary energy,costs and carbon dioxide emissions with respect to absorption heat pump with the increasing of compressor proportion parameter.Future researches should focus on the construction of this heat pumps integrated in chemical processes as a biogas plant or trigeneration systems.     

等温或非等温颗粒吸附动力学模型:应用于吸附热泵(英文)

Understanding the interaction between a fluid and a solid phase is of fundamental importance to the design of an adsorption process.Because the heat effects associated with adsorption are comparatively large,the as-sumption of isothermal behavior is a valid approximation only when uptake rates are relatively slow.In this article,we propose to determine when it is needed to choose the isothermal or non-isothermal assumption according to two physical parametersα(ratio convection/capacity) andβ(quantity of energy/capacity) .The proposed problem is solved by a mathematical method in the Laplace domain.Whenα→∞(infinitely high heat transfer coefficient) or β→0(infinitely large heat capacity) ,the limiting case is isothermal.When the diffusion is rapid(α10) the kinetics of sorption is controlled entirely by heat transfer.If the adsorption process is to be used as a heat pump,it shall be represented by an isotherm model withαandβas high as possible.     

Optimization of volume to point conduction problem based on a novel thermal conductivity discretization algorithm

A conduction heat transfer process is enhanced by filling prescribed quantity and optimized-shaped high thermal conductivity materials to the substrate. Numerical simulations and analyses are performed on a volume to point conduction problem based on the principle of minimum entropy generation. In the optimization, the arrange-ment of high thermal conductivity materials is variable, the quantity of high thermal-conductivity material is constrained, and the objective is to obtain the maximum heat conduction rate as the entropy is the minimum. A novel algorithm of thermal conductivity discretization is proposed based on large quantity of calculations. Compared with other algorithms in literature, the average temperature in the substrate by the new algorithm is lower, while the highest temperature in the substrate is in a reasonable range. Thus the new algorithm is fea-sible. The optimization of volume to point heat conduction is carried out in a rectangular model with radiation boundary condition and constant surface temperature boundary condition. The results demonstrate that the al-gorithm of thermal conductivity discretization is applicable for volume to point heat conduction problems.     

基于红外测温的对流换热系数反识别算法研究

The heat transfer coefficient in a multidimensional heat conduction problem is obtained from the solution of the inverse heat conduction problem based on the thermographic temperature measurement. The modified one-dimensional correction method （MODCM）, along with the finite volume method, is employed for both two- and three-dimensional inverse problems. A series of numerical experiments are conducted in order to verify the effectiveness of the method. In addition, the effect of the temperature measurement error, the ending criterion of the iteration, etc. on the result of the inverse problem is investigated. It is proved that the method is a simple, stable and accurate one that can solve successfully the inverse heat conduction problem.     

Heat Transfer between Immersed Horizontal Tubes and Aerated Vibrated Fluidized Beds

Heat transfer coeffients between an immersed horizontal tube and an aerated vibrated fluldlzed bed are measured. There is a maximum value in the h-Г experlmental curve. The heat trander coefllcient increases with decreases in particle diameter in the fully fluidized region. The particle density has less effect on the heat transfer coetftclents. High smplltude and low frequency, or low amplitude and high frequency are favorable to heat transit. Exceedingly high gas veloclty is unfavorable to the surface-bed heat transfer. A model based on the ‘pocket‘ theory was proposed for predicting the surface-to-bed heat trausfer coefllclents in fully fluldlzed region. The predlctlons from the model were compared with observed data The reasonable fit suggests the adequacy of the model.     

Performance enhancement of water bath heater at natural gas city gate station using twisted tubes

Natural gas is transported from producing regions to consumption regions by using transmission pipelines at high pressures. At consumption regions, the pressure of natural gas is reduced in city gate stations(CGSs). Before the pressure reduction process, the temperature of natural gas is increased usually by using a water bath heater,which burns natural gas as fuel, to protect against freezing of natural gas. These types of heat exchangers have a low efficiency and consume a lot of fuel to generate the required heat. In the current study, the twisted configuration of the heating coil is proposed and investigated to enhance the heat transfer through a water bath heater with a nominal capacity of 1000 m~3·h~(-1). Firstly, the implementation procedure is validated with data collected from the CGS of Qaleh-Jiq(located in Golestan province of Iran). A very good agreement is achieved between the obtained results and the real data. Then, three different twist ratios are considered to examine the twisting effects. The proposed technique is evaluated in the terms of velocity, temperature, and pressure variations, and the results are compared with the conventional case, i.e. straight configuration. It is found that both the heat transfer rate and the pressure drop augment as the twist ratio is raised. Finally, it is concluded that the twisted tubes can reduce the length of the gas coil by about 12.5% for the model with low twist ratio, 18.75% for the model with medium twist ratio, and 25% for the model with high twist ratio as compared to the straight configuration.     

基于流股虚拟温度综合大规模多流股换热器网络

Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference contribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual temperature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network （MSHEN） is regarded as an objective function, and genetic/simulated annealing algorithm （GA/SA） is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the basis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy （T-H） diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calculation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in searching the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature difference contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construction material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network （HEN） with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort.     

合成硝基麝香溶液结晶分离研究

为了开发低共熔组成酮麝香、二甲苯麝香混合物溶液结晶新过程,计算得到酮麝香、二甲苯麝香、溶剂三元相图。在此基础上研究了麝香混合物溶液结晶分离方法,提出了轮流加入乙腈和庚烷从低共熔组成麝香混合物中,分级冷却结晶分离得到2种产品的过程。由三元相图得到理论产量并进行试验验证,结果表明加入乙腈一级结晶可得到纯度为97.5%的二甲苯麝香,加入庚烷二级结晶后酮麝香的纯度为98.1%。     

酮麝香、二甲苯麝香和双溶剂四元体系液液相平衡研究

本文计算并测定了酮麝香、二甲苯麝香、二甲基亚砜(或乙腈)和庚烷(或环己烷)四元体系的液液相平衡,试验结果与计算值基本吻合。平衡双液相中两种麝香的比例不同于原料,两液相中两种麝香分别得到了富集,其中二甲基亚砜(或乙腈)相中富含酮麝香、庚烷(或环己烷)相中富含二甲苯麝香,这种液相分相可用于分离麝香混合物。本文的研究为麝香混合物的分离提供了理论指导。此外,采用本文的方法还可以预测较难测定的多元固、液混合物的相平衡关系。     

含麝香体系多元溶液固液平衡研究

测定了酮麝香、二甲苯麝香在单一溶剂和混合溶剂中的溶解度以及酮麝香的中间体 2 ,6 二甲基 4 叔丁基苯乙酮在不同溶剂中的溶解度 ,并且测定了多溶质多溶剂体系的固液平衡 ,采用UNIFAC活度系数法进行以上体系的固液平衡计算 ,计算结果与实验测定结果吻合良好。采用文中提出的方法不仅可以预测多溶质体系在溶液中共同达到饱和时的溶解度 ,而且可以预测部分溶质达到饱和时的溶解度 ,这对于溶液结晶具有重要的指导意义     

长碳链二元酸在人工合成麝香酮方面的应用

人工合成已经成为麝香酮的主要来源,但由于原料供应和原料价格问题,许多合成途径都无法实现工业化生产。微生物法生产的长碳链二元酸为人工合成麝香提供了丰富廉价的原料资源,本文概述了以12-16碳二元酸为原料的麝香酮合成途径。     

用熔融结晶技术提纯人造麝香DDHI

用熔融结晶技术从DDHI混合物中分离提纯人造麝香DDHI,结晶的适宜条件为 :结晶时间2h ,降温速率 4℃ /h ,通氮气 ,发汗时升温速率为 6℃ /h ,发汗时间为 30min。经过二级结晶 ,w(DDHI) =99 2 % ,收率为 6 3 2 %。     

减压精馏-熔融结晶耦合装置提纯人造麝香的研究

通过减压精馏-熔融结晶耦合技术研究提高人造麝香(DDHI)含量的原理和工艺流程。实验结果表明,该技术可使人造麝香DDHI的纯度达到98%,总收率达到54%,比原工艺提高13%。     

人造麝香DDHI重结晶的研究

测定了人造麝香DDHI在不同质量分数的乙醇水溶液中的溶解度 ,并用重结晶的方法提纯DDHI,适宜的工艺条件为 :用质量分数为 80 %的乙醇水溶液作为溶剂 ,将液态DDHI溶于 6 0℃的溶剂中 ,缓慢冷却至 2 0℃进行重结晶 ,溶液的pH =7,乙醇水溶液与DDHI的质量比为 2 3～2 6 ,进行二至三次重结晶可得到质量分数大于 99 5 %的DDHI     

用降膜结晶法分离人造麝香的研究

用降膜结晶技术提纯人造麝香,考察了物料循环时间、油浴温度和料液的过热度对结晶过程的影响,分析了发汗温度和发汗升温速率与结晶过程中分配系数及结晶率的关系。综合考察产品质量及生产效率,得到用降膜结晶提纯麝香DDHI的适宜的生产条件。在适宜条件下,对DDHI的质量分数为75％左右的原料进行三级结晶,每级母液及发汗液循环回上一级使用,最后所得产品质量分数大于98％,结晶率达到53％以上。