半再生催化重整装置热载体系统优化与节能分析

为充分挖掘中国石化青岛石油化工有限责任公司催化重整装置的节能降耗减排潜力,对该公司250 kt/a半再生催化重整装置热载体系统的热量平衡进行分析,并优化热载体系统的换热流程和蒸发塔、分馏塔、稳定塔的操作参数。结果表明,该催化重整装置的热载体系统可以停用热载体炉,停用后可以节约用电321.14 (MW.h)/a,节省瓦斯消耗621.96 t/a,减少CO₂排放约1 750 t/a,节能增效约273.22 万元/a。     

Axial uniformity diagnosis of coaxial surface wave linear plasma by optical emission spectroscopy

The coaxial surface wave linear plasma with preeminent axial uniformity is developed with the 2.45 GHz microwave generator. By optical emission spectroscopy, parameters of the argon linear plasma with a length over 600 mm are diagnosed under gas pressure of 30 and 50 Pa and different microwave powers. The spectral lines of argon and Hβ (486.1 nm) atoms in excited state are observed for estimating electron excitation temperature and electron density. Spectrum bands in 305–310 nm of diatomic OH (${{\rm{A}}}^{2}{{\rm{\Sigma }}}^{+}-{{\rm{X}}}^{2}{{\rm{\Pi }}}_{{\rm{i}}}$) radicals are used to determine the molecule rotational temperature. Finally, the axial uniformity of electron density and electron excitation temperature are analyzed emphatically under various conditions. The results prove the distinct optimization of compensation from dual powers input, which can narrow the uniform coefficient of electron density and electron excitation temperature by around 40% and 22% respectively. With the microwave power increasing, the axial uniformity of both electron density and electron excitation temperature performs better. Nevertheless, the fluctuation of electron density along the axial direction appeared with higher gas pressure. The axial uniformity of coaxial surface wave linear plasma could be controlled by pressure and power for a better utilization in material processing.     

A novel double dielectric barrier discharge reactor with high field emission and secondary electron emission for toluene abatement

Dielectric barrier discharge (DBD) has been extensively investigated in the fields of environment and energy, whereas its practical implementation is still limited due to its unsatisfactory energy efficiency. In order to improve the energy efficiency of DBD, a novel double dielectric barrier discharge (NDDBD) reactor with high field emission and secondary electron emission was developed and compared with traditional DDBD (TDDBD) configuration. Firstly, the discharge characteristics of the two DDBD reactors were analyzed. Compared to TDDBD, the NDDBD reactor exhibited much stronger discharge intensity, higher transferred charge, dissipated power and gas temperature due to the effective utilization of cathode field emission and secondary electron emission. Subsequently, toluene abatement performance of the two reactors was evaluated. The toluene decomposition efficiency and mineralization rate of NDDBD were much higher than that of TDDBD, which were 86.44%–100% versus 28.17%–80.48% and 17.16%–43.42% versus 7.17%–16.44% at 2.17–15.12 W and 1.24–4.90 W respectively. NDDBD also exhibited higher energy yield than TDDBD, whereas the overall energy constant ${k}_{{\rm{overall}}}$ of the two reactors were similar. Finally, plausible toluene decomposition pathway in TDDBD and NDDBD was suggested based on organic intermediates that generated from toluene degradation. The finding of this study is expected to provide reference for the design and optimization of DBD reactor for volatile organic compounds control and other applications.     

Argon plume transition from a hollow swell to a diffuse swell with increasing amplitude of a trapezoidal voltage

Atmospheric pressure plasma jets can generate a remote plasma plume, which usually presents a conical or cylindrical morphology. Despite a few morphologies being observed, efforts should be made to obtain more plume structures because streamer dynamics may be revealed from them. For this purpose, an argon plasma plume excited by a trapezoidal voltage is investigated, which presents two kinds of swells (a hollow swell and a diffuse swell) with increasing voltage amplitude (V_p). The results indicate that there are two positive discharges (D_p1 and D_p2) and one negative discharge (D_n) per voltage cycle for both of the swells. With increasing Vp, the inception voltage and discharge intensity increase for every positive discharge, while they decrease for the negative discharge. Fast photography reveals that the positive streamer (D_p2) leaves different tracks in the two swells, which are curved in the hollow swell and randomly branched in the diffuse swell. The different tracks of D_p2 are explained with the consideration of applied field strength and residual positive ions of D_p1. The existence of residual positive ions is finally verified from optical emission spectra.     

Study on the characteristics of non-Maxwellian magnetized sheath in Hall thruster acceleration region

The secondary electron emission (SEE) and inclined magnetic field are typical features at the channel wall of the Hall thruster acceleration region (AR), and the characteristics of the magnetized sheath have a significant effect on the radial potential distribution, ion radial acceleration and wall erosion. In this work, the magnetohydrodynamics model is used to study the characteristics of the magnetized sheath with SEE in the AR of Hall thruster. The electrons are assumed to obey non-extensive distribution, the ions and secondary electrons are magnetized. Based on the Sagdeev potential, the modified Bohm criterion is derived, and the influences of the non-extensive parameter and magnetic field on the AR sheath structure and parameters are discussed. Results show that, with the decrease of the parameter q, the high-energy electron leads to an increase of the potential drop in the sheath, and the sheath thickness expands accordingly, the kinetic energy rises when ions reach the wall, which can aggravate the wall erosion. Increasing the magnetic field inclination angle in the AR of the Hall thruster, the Lorenz force along the $x$ direction acting as a resistance decelerating ions becomes larger which can reduce the wall erosion, while the strength of magnetic field in the AR has little effect on Bohm criterion and wall potential. The propellant type also has a certain effect on the values of wall potential, secondary electron number density and sheath thickness.     

Integrated data analysis on the electron temperature profile of HL-2A with the Bayesian probability inference method

Data analysis on tokamak plasmas is mainly based on various diagnostic systems, which are usually modularized and independent of each other. This leads to a large amount of data not being fully and effectively exploited so that it is not conducive to revealing the deep physical mechanism. In this work, Bayesian probability inference with machine learning methods have been applied to the electron cyclotron emission and Thomson scattering diagnostic systems on HL-2A/2M, and the effects of integrated data analysis (IDA) on the electron temperature of HL-2A with Bayesian probability inference are demonstrated. A program is developed to infer the whole electron temperature profile with a confidence interval, and the program can be applied in online analysis. The IDA results show that the full profile of the electron temperature can be obtained and the diagnostic information is more comprehensive and abundant with IDA. The inference models for electron temperature analysis are established and the developed programs will serve as an experimental data analysis tool for HL-2A/2M in the near future.     

6110直喷式柴油机排放特性分析

测量了 6 110直喷式柴油机排气污染物 THC、CO、NOx 以及 PT的排放量 ,并分析了各种污染物的排放规律 ,对 THC排放与有效燃油消耗率 be、PT与 NOx 排放、SOF与 THC排放之间的关系做了研究。结果表明 6 110直喷式柴油机 THC和 CO的高排放区出现在小负荷工况 ;PT的高排放区出现在低负荷和高负荷工况 ;降低 NOx 排放的重点应放在小负荷工况和高速工况。柴油机的 be 与 THC排放随工况的变化表现出相似的变化规律。在较大的工况范围之内 ,PT和 NOx 排放之间存在折中关系 ;而在少数工况区域 ,PT和 NOx 排放之间存在一致性。 PT中的 DS与 NOx 排放之间始终存在着折中关系 ,而 SOF与 NOx 排放之间却存在着一定程度的一致性。在 THC的高排放工况 ,SOF也具有比较高的排放量     

水平强迫气流下木屑逆向阴燃过程的实验研究

在搭建的小型阴燃实验台上,对木屑的一维水平逆向阴燃过程进行实验研究,获得了稳定的逆向阴燃过程,并对各种因素对阴燃过程的影响进行了试验.结果表明,随着空气流速的增加,阴燃的传播速度随之增加,而材料含水量的增大会降低阴燃的传播速度.另外对阴燃过程中产生的CO2和CO进行分析,计算出这两种气体在不同空气流速下的平均排放速率.     

燃烧优化降低锅炉NOx排放的试验研究

对于已经采用低NOx燃烧技术的电站锅炉 ,燃烧优化仍然是降低NOx排放的首选方法。通过对某电厂 1 0 2 5t/h锅炉进行燃烧调整试验研究 ,确定了锅炉优化运行方式 ,分析锅炉效率和NOx排放量与电站锅炉运行参数的关系 ,以指导锅炉的高效低NOx的运行     

煤粉燃烧污染物排放特性的试验研究

由煤燃烧产生的NOx、SOx引起的污染受到世界各国的重视,降低污染物排放成为燃烧研究的重要课题.选择了某电厂常用的4种褐煤和3种烟煤,研究了单煤及其混煤的污染物排放特性.结果表明:氧浓度增加时,或煤粉较细时,NOx的排放增加;而水分能降低NOx的排放;SOx的排放规律不明显.