乙炔发生温度控制改造

在电石法生产PVC工艺中,乙炔生产最主要的工艺控制指标是乙炔发生温度,为稳定发生温度,将乙炔发生温度由手控改为自控,不但温度稳定,降低工人的劳动强度,而且取得了显著的经济效益。     

Detonation temperature of an emulsion explosive with a polymer sensitizer

Dependences of the brightness temperatures of the detonation front and detonation products on detonation pressure were determined in the range of 0.7–9.4 GPa by a pyrometric method. The pressure was varied by changing the initial density of the emulsion explosive in the range of 0.43–1.2 g/cm³. Polymer microballoons were used as sensitizer. The dependence of the brightness temperature in the Chapman–Jouguet plane on detonation pressure was found to be nonmonotonic. In the investigated pressure range, the measured temperature values varied from 2250 to 1830 K. A comparative analysis of the application of polymer and glass microballoons as sensitizers was performed. The obtained experimental data were compared with the calculation results available in the literature.     

A Detonation Model of High/Low Velocity Detonation

A new detonation model that can simulate both high and low velocity detonations is established using the least action principle. The least action principle is valid for mechanics and thermodynamics associated with a detonation process. Therefore, the least action principle is valid in detonation science. In this model, thermodynamic equilibrium state is taken as the known final point of the detonation process. Thermodynamic potentials are analogous to mechanical ones, and the Lagrangian function in the detonation process is L=T−V. Under certain assumptions, the variation calculus of the Lagrangian function gives two solutions: the first one is a constant temperature solution, and the second one is the solution of an ordinary differential equation. A special solution of the ordinary differential equation is given.     

乙炔与氯化氢在低温下混合的安全性研究

乙炔与氯化氢混合气体中含有由游离氯与乙炔反应生成的氯乙炔和二氯乙炔组分时,存在着易燃、易爆的安全隐患,这两种组分的产生原因主要是混合温度高。笔者提出了将乙炔和氯化氯气体先分别在-14℃下进行除水后再混合的预防措施,可使气体混合工段生产的安全性在原来的基础上提高70%。     

煤制乙炔裂解气的降温工艺

介绍了煤制乙炔工艺中裂解气降温工艺流程并对关键设备的选型进行了详细计算。     

乙炔废酸高温裂解再生制酸生产实践

介绍了中国石化长城能源化工(宁夏)有限公司230 kt/a乙炔配套42 kt/a废酸再生装置的工艺流程和运行状况。该套废酸生产装置采用二转二吸干法制酸工艺,包括裂解、净化、干吸、转化、尾气吸收等工序。投入运行后存在冬天补废酸困难、运行负荷低、产品酸浓度不合格、SO2主风机回流管道腐蚀、裂解炉与主燃烧器连接处烧穿等问题。经过生产调优和技术改造后,装置运行稳定,各项指标达到设计值,处理废硫酸2.5 m3/h、酸性气250 m3/h,消耗天然气约400 m3/h。     

乙炔发生器上加料斗排空乙炔气的回收

研究了电石法乙炔发生器上加料斗置换排空乙炔气的回收方法,阐述了3种回收方法的设计思路和工艺流程,并对回收的乙炔气进行了经济效益测算。     

Detonation Velocity Deficits and Curvature Radius of Mild Detonation Cords

In order to study the detonation velocity deficits of wound mild detonation cords, a physical model and a theoretical mathematical equation for detonation velocity deficits of wound mild detonation cords were established based on the detonation wave’s corner effects and delay time phenomenon by using non‐dimensional analysis method. Besides, a semi‐empirical formula for detonation velocity deficit of wound mild detonation cords in the same charge size was obtained through experiments and curve fitting. Both the theoretical mathematical equation and the semi‐empirical formula show that the detonation velocity deficit of wound mild detonation cords and the reciprocal of the curvature radius have an exponential relationship.     

Direct conversion of methane to acetylene or syngas at room temperature using non-equilibrium pulsed discharge

Non-catalytic direct conversion of methane to valuable products was studied using non-equilibrium pulsed discharge under the conditions of ambient temperature and atmospheric pressure. Acetylene was produced with 95% selectivity and 52% methane conversion. An addition of oxygen, carbon dioxide and steam contributed significantly to suppress the carbon deposition and produced carbon monoxide as well as acetylene. Methane conversion increased with an increase in the pulse frequency while the product selectivity remained almost constant. The selectivity depended on the composition of the feed gas. The effect of the partial pressure of oxygen was examined, and it was found that the pulsed discharge would be able to produce synthesis gas by partial oxidation of methane. Carbon monoxide selectivity of 79% with methane conversion of 76% was obtained under the conditions of CH₄/O₂=25/25 cm³ min⁻¹, gap distance of 10 mm and the frequency of 45 Hz.     

Estimating Heats of Detonation and Detonation Velocities of Aromatic Energetic Compounds

A new method is introduced to predict reliable estimation of heats of detonation of aromatic energetic compounds. At first step, this procedure assumes that the heat of detonation of an explosive compound of composition C_aH_bN_cO_d can be approximated as the difference between the heat of formation of all H₂O CO₂ arbitrary (H₂O, CO₂, N₂) detonation products and that of the explosive, divided by the formula weight of the explosive. Overestimated results based on (H₂O CO₂ arbitrary) can be corrected in the next step. Predicted heats of detonation of pure energetic compounds with the product H₂O in the liquid state for 31 aromatic energetic compounds have a root mean square (rms) deviation of 2.08 and 0.34 kJ g⁻¹ from experiment for (H₂O CO₂ arbitrary) and new method, respectively. The new method also gives good results as compared to the second sets of decomposition products, which consider H₂, N₂, H₂O, CO, and CO₂ as major gaseous products. It is shown here how the predicted heats of detonation by the new method can be used to obtain reliable estimation of detonation velocity over a wide range of loading densities.     

Titania Nanocrystalline Prepared by Detonation Method and Calculation of Detonation Parameters

As a promising method for synthesizing nanosized materials, detonation method was used to prepare TiO₂ nanoparticles. A new method for predicting the Chapman‐Jouguet (C‐J) detonation parameters of C_aH_bO_cN_dTi_e explosives, such as detonation heat, detonation temperature, and detonation pressure, was introduced according to the approximate reaction equations of detonation. The coefficient of oxygen balance of explosive was also calculated according to the specific detonation synthesis experiment. The calculation method was more useful in predicting the formation processes of detonation products and optimizing the experimental procedure. It could also support theory foundation for further experiments to some extent.     

乙炔加氢串联反应器全周期乙炔转化率最优分配研究

在乙炔加氢反应器的实际生产运行过程中,乙炔加氢反应大部分在第一床层,加氢反应放出的大量热量使得床层内温度高于最佳反应温度范围,致使乙烯选择性降低,乙烯产量下降,而在进行全周期操作优化时并未考虑到此问题。因此,首先考虑温度对绿油累积的影响,修正了催化剂失活动力学方程;其次,为保证反应器各床层内温度都在最佳反应温度范围,从化学反应工程理论和实际生产过程中的安全性两个角度出发,给出两种反应器各床层乙炔转化率分配方案;最后,在常规全周期操作优化模型中添加乙炔转化率约束,建立全周期乙炔转化率分配操作优化模型,并对两种乙炔转化率分配方案进行全周期操作优化。优化结果表明,两种乙炔转化率分配方案操作优化的乙烯产量要远远高于常规操作优化,且乙炔转化率方案为33∶33∶33时,乙烯产量最高,而考虑实际生产过程中的安全性,乙炔转化率分配方案为43∶47∶10时具有更好的效果。     

The effect of changes in synthesis temperature and acetylene supply on the morphology of carbon nanocoils

Carbon nanocoils (CNCs) with controlled shape, coil diameter and coil pitch have been synthesized in a chemical vapor deposition (CVD) system by changing the reaction temperature and acetylene flow rate. It is found that three-dimensional CNCs are produced at a lower temperature (700–770 °C), while a higher temperature (810 °C) leads to the growth of straight carbon nanofibers (CNFs). CNC–CNF hybrid structures are produced by increasing growth temperature from 750 to 810 °C during a single synthesis run, while CNF–CNC hybrid structures are produced by decreasing the temperature from 810 to 750 °C. Similarly, by changing growth temperature from 750 to 810 °C and then back to 750 °C during a single run, CNC–CNF–CNC complex hybrid structures can be obtained. During the CVD process, the pulsing of acetylene and the changing of acetylene flow rate are also found to be effective in controlling the structure of CNCs. CNCs with periodic helical structures can be produced by interrupting the acetylene flow or changing its flow rate periodically. It is found that the higher the flow rate of acetylene, the smaller the coil pitch and diameter of the grown CNCs.     

Dependence of the Shape of a Detonation Wave Front on the Detonation Wave Velocity upon Detonation of a Cylindrical Charge

The transition of a system of partial differential equations which describe the stationary flow behind the shock–wave front of a detonation complex upon detonation of a cylindrical charge to a system of ordinary differential equations is performed by means of the series expansion in terms of the radial variable. The necessary equations for determination of the derivatives of solutions with respect to the parameters and the initial conditions for them are formulated. Imposing the condition of continuous extendibility of the solutions leads to equations that allow one to determine the shape of a shock–wave front as a function of wave velocity.     

Detonation logic elements

We consider the classification of detonation logic elements (DLE), that is, devices in which logical operations are effected by means of explosive signals. The technical implementation of the DLE studied is based on the physical principle of the “corner effect.” Methods of describing the functional properties of DLE using Boolean functions are analyzed. Examples are given of the application of Boolean functions to detonation elements of single-step and two-step logic. Institute of Specialized Mechanical Engineering, N. é. Bauman Moscow State Technical University, Moscow 107005. Translated from Fizika Goreniya i Vzryva. Vol. 30, No. 5, pp. 123–126, September–October, 1994.