Comprehensive emergy evaluation and optimization of corn straw power generation system: a case study

Biomass energy has become an important measure to alleviate ecological environment security and energy supply security in China. Emergy accounting method is used to analyze and evaluate economy, environment, and sustainability of corn straw generation system, which includes corn planting subsystem, collection and transportation subsystem, and corn straw power generation subsystem. The key substances that need to be optimized in the system are identified by using sensitivity analysis. Based on the position of key substances in the system, emergy accounting optimization methodology is conducted. Corresponding optimization design scheme is proposed based on the “3R” (reduce, reuse, and recycle) principle of circular economy. Current study shows that emergy yield ratio, emergy investment ratio, environmental loading ratio, and emergy sustainability index of the corn straw power generation system are 3.69, 2.68, 1.61, and 2.29, respectively, which are better than wind power generation system and thermal power generation system. In addition, it is proposed that the fertilizer alternative plan and the transportation redesign plan can replace 50,000 tons potash and reduce equipment resources by 20% and energy resources input by 30%. Economy and sustainable development of the system is significantly improved. The optimization design method based on the “3R“ principle proposed in this paper can provide a useful reference for the research in the field of resource recycling.     

泔脚的厌氧消化处理可行性研究

介绍了作者在泔脚厌氧消化处理方面的研究情况，作者通过新鲜泔脚的特性分析试验、脱水实验、最佳接种率，最佳含水率实验，最大有机负荷实验等一系列系统的实验。完成了工程小试，达到了实验目的，得到了一些对实际工程应用十分有用的数据。认为厌氧消化对泔脚的处理是生态上比较合理，经济上可行的处理方法。     

喷嘴角度对脱硫塔内气液两相流场的影响

提出了采用数值模拟的方法研究喷嘴角度对脱硫塔内部气液两相流场的影响。由于实际脱硫塔尺寸庞大,给实验研究带来困难且成本很高,在数值模拟平台上,分别模拟了45°、75°和-30°3种喷嘴角度布置下脱硫塔内部速度场、温度场变化以及湍流强度的分布情况。结果表明,在角度为-30°布置时速度场变化不是很剧烈,脱硫塔进出口温差比较理想,湍流强度在脱硫塔底部较大随着塔高的增加缓慢降低,这样有助于气液两相均匀混合,并控制出口烟温,有利于提高脱硫效率。     

活性染料K-2BP、KN-B和KN-R在椰壳活性炭上的脱色性能

开展椰壳活性炭对活性染料K-2BP、KN-B和KN-R的吸附脱色研究。发现K-2BP、KN-B和KN-R在该型活性炭上的吸附脱色率均随初始pH值的降低、温度的升高、染料初始浓度的降低、活性炭用量的增加以及NaCl盐度的增加而增加。在pH=7和T=25℃下,K-2BP、KN-B和KN-R在活性炭上的等温吸附规律符合Langmuir模型方程,最大饱和吸附量Qmax分别为263.15、256.41和250 mg/g,吸附自由能△G298 K分别为-10.632、-3.783和-2.805 kJ/mol;该条件下K-2BP、KN-B和KN-R的动力学吸附规律均符合准一级动力学吸附方程。等温吸附研究和吸附动力学研究均表明,相同条件下3种活性染料在该型活性炭上的吸附效果由高到低的顺序为:K-2BP>KN-B>KN-R。     

Evaluation of hazard range for the natural gas jet released from a high-pressure pipeline: A computational parametric study

In the present study, the hazard range of the natural gas (NG) jet released from a high-pressure pipeline was investigated. A one-dimensional integral model was combined with a release model to calculate the length and width (i.e., size), and the shape of NG jet release. The physical parameters affecting the jet release of NG were categorized into three types: source release, environmental and time parameters. The effects of each type of parameters on the gas jet release rate, size and shape were evaluated systematically. The results show that all of these parameters have important influence on the hazard range of NG jet release. The source release parameters, including the pipeline length, the operation pressure of the pipeline, the release hole diameter and the pipe diameter, dominate the gas release rate through a hole and therefore the length and width of gas jet release. The gas jet release rate and size are found to be highly correlative with these parameters in terms of power curve regression analysis. The environmental parameters including the atmospheric stability, the ambient wind speed and the source height, have no influence on the gas jet release rate but have influence on the hazard range of gas jet by the turbulent mixing and dilution of NG with air. The time parameters including the concentration averaged time and the valve closing time which are related to the unsteady state jet release of NG, also show the influence on the hazard range of gas jet release. The results show that the decreasing valve closing time and increasing gas concentration averaged time are in favor of reducing the length and width of gas jet release. In addition, these computational parametric studies indicate that the parameters of source release and time have no significant influence on the shape of gas jet release (i.e., jet length/width ratio, LWR) which can maintain the values between 7 and 8. However, the environmental parameters have influence on the shape of gas jet release. These comprehensive investigations provide useful database of evaluating the hazard range for NG jet released from a hole on a high-pressure pipeline and also provide the foundation of decision-making for further fire and/or explosion evaluation and people evacuation.     

Experimental study on leak detection and location for gas pipeline based on acoustic method

The leak of gas pipelines can be detected and located by the acoustic method. The technologies of recognizing and extracting wave characteristics are summarized in details in this paper, which is to distinguish leaking and disturbing signals from time and frequency domain. A high-pressure and long distance leak test loop is designed and established by similarity analysis with field transmission pipelines. The acoustic signals collected by sensors are de-noised by wavelet transform to eliminate the background noises, and time-frequency analysis is used to analyze the characteristics of frequency domain. The conclusion can be drawn that most acoustic signals are concentrated on the ranges of 0-100 Hz. The acoustic signal recognition and extraction methods are verified and compared with others and it proves that the disturbing signals can be efficiently removed by the analysis of time and frequency domain, while the new characteristics of the accumulative value difference, mean value difference and peak value difference of signals in adjacent intervals can detect the leak effectively and decrease the false alarm rate significantly. The formula for leak location is modified with consideration of the influences of temperature and pressure. The positioning accuracy can be significantly improved with relative error between 0.01% and 1.37%.     

石头口门水库藻类种群组成特征研究

2008年9月5日采集石头口门水库42份水样,制片,电子显微镜下观察,研究结果表明：藻类共有5门,7纲,15目,27科,47属。其中,绿藻门最多,2纲,4目,9科,20属;其次是硅藻门,2纲,5目。7科,11属;再次是蓝藻门,1纲,3目,8科,13属;黄藻门较少,1纲,2目,2科,2属;红藻门仅有1纲,1目,1科,1属。采用血球计数板计数法计算原始水样中的藻类的平均密度。得出石头口门水库藻类的平均密度为3．80×10^4个／L,变动范围在1．00×10^4～8．00×10^4个／L之间。绿藻门属的数量和密度分别占到了42,55％,88．39％,是石头口门水库的优势藻类种群。     

除尘系统粉尘和SO2排放在线监测系统

详细阐述了除尘系统粉尘和SO2排放在线监测系统的组成,各单元的结构及工作原理,介绍了系统各硬件设备的性能特点及设备选型,提出了完整的系统配置、构架及监测数据处理与网络传输的方法,实时监测软件的功能.