不含卤素的低燃性弹性体混料

开发高阻燃性和对火焰扩展稳定性的电缆制品,是近年来摆在电子工业面前的一个重要任务。含橡胶绝缘层的电线、电缆即属于这类制品,要求在着火条件下长时间保持工作能力。这一问题的解决,对无线电工业、航空工业。

低燃聚合纤维材料

防火的成纤聚合物和纺织材料领域的研究包括下述三方面: 一开发新颖阻燃剂(FR)或阻燃体系(FRS),这对成纤聚合物具有高效防火效果,并且有可能对化纤或纺织业企业中聚合物材料进行实用性改性; 一在各种组分的阻燃剂存在下,研究成纤聚合物的热氧化分解作用;

Combustion characteristics of semicokes derived from pyrolysis of low rank bituminous coal

Various semicokes were obtained from medium-low temperature pyrolysis of Dongrong long flame coal.The proximate analysis,calorific value and Hardgrove grindability index(HGI) of semicokes were determined,and the ignition temperature,burnout temperature,ignition index,burnout index,burnout ratio,combustion characteristic index of semicokes were measured and analyzed using thermogravimetry analysis(TGA).The effects of pyrolysis temperature,heating rate,and pyrolysis time on yield,composition and calorific value of long flame coal derived semicokes were investigated,especially the influence of pyrolysis temperature on combustion characteristics and grindability of the semicokes was studied combined with X-ray diffraction(XRD) analysis of semicokes.The results show that the volatile content,ash content and calorific value of semicokes pyrolyzed at all process parameters studied meet the technical specifications of the pulverized coal-fired furnaces(PCFF) referring to China Standards GB/T 7562-1998.The pyrolysis temperature is the most influential factor among pyrolysis process parameters.As pyrolysis temperature increases,the yield,ignition index,combustion reactivity and burnout index of semicokes show a decreasing tend,but the ash content increases.In the range of 400 and 450 °C,the grindability of semicokes is rational,especially the grindability of semicokes pyrolyzed at 450 °C is suitable.Except for the decrease of volatile content and increase of ash content,the decrease of combustion performance of semicokes pyrolyzed at higher temperature should be attributed to the improvement of the degree of structural ordering and the increase of aromaticity and average crystallite size of char.It is concluded that the semicokes pyrolyzed at the temperature of 450 °C is the proper fuel for PCFF.

Structural and Magnetic Properties of Chemically Synthesized Pd-Modified NiFe2O4 Nanoparticles

Magnetic nanoparticles of NiFe2O4-Pd composites have been synthesized using a simple, low cost, sol-gel auto-combustion method. As-prepared samples were sintered at 800℃ for 6 h in order to develop the crystalline phase. X-ray diffraction confirmed the spinel structure of the ferrite samples. Structural morphology and size of the nanoparticles were evaluated using a field emission scanning electron microscope. Magnetic hysteresis loops were obtained at 300 and 100 K using a physical properties measurement system. The value of saturation magnetization was observed to decrease at the temperatures with the increase of Pd contents up to 5% but then a sudden rise in saturation magnetization was observed for the addition of 10% Pd in NiFe2O4.

Lowest Temperature Miniature Fuel Cell with Modified PS PEM Membrane and Fueled with Nitrogen, Sulfur and Oxygen Containing Fuels

Polymer exchange membrane fuel cells （PEMFC） are objects of the current engineering technology and these are versatile generators for electrical energy. There are various kinds from them, but all of them are going on work at highest temperature. There isn＇t a PEMFC which can run at room temperature, like 20 ℃. In this study there is a aim for constructing such one for alternative fuels utilisation. PS and many electroconducting polymer formulations were proved by different researchers for PEM benefications, but here PS was synthesized without containing metalic contaminants and after converted to the PEM membrane.

Type Selection of Burning Equipment for Low Volatile Coal Boilers

When designing and selecting burning equipment for low volatile coal fired boilers,the primary concerns are about coal ignition and burnout.The characteristics of ignition and burnout are analyzed for low volatile coal and the technical measures are discussed for enhancing the combustion and burnout.The adaptability of tangential firing,wall firing and double-arch firing for low volatile coal is studied.Based on the statistic analysis for the main design parameters of domestic low volatile coal fired boilers with tangential firing,wall firing or double-arch W flame firing,the thermal performance for various boiler furnaces is recommended.The combustion systems for different types of boilers are also put forward for coals with different volatiles.

Combustion characteristics of low concentration coal mine methane in divergent porous media burner

Low-concentration methane(LCM) has been one of the biggest difficulties in using coal mine methane.And previous studies found that premixed combustion in porous media is an effective method of low calorific gas utilization. This paper studied the combustion of LCM in a divergent porous medium burner(DPMB) by using computational fluid dynamics(CFD), and investigated the effect of gas initial temperature on combustion characteristic, the distribution of temperature and pollutant at different equivalence ratios in detail. Besides, the comparison of divergent and cylindrical burners was also performed in this paper. The results show that: the peak temperature in DPMB increases as the increasing of equivalence ratio, which is also suitable for the outlet NO discharge; the linear correlation is also discovered between peak temperature and equivalence ratios; NO emission at the initial temperature of 525 K is 5.64 times,larger than NO emission at the initial temperature of 300 K. Thus, it is preferable to balance the effect of thermal efficiency and environment simultaneously when determining the optimal initial temperature range. The working parameter limits of divergent burner are wider than that of cylindrical one which contributes to reducing the influence of LCM concentration and volume fluctuation on combustion.

Experimental simulation of the relative contribution of volatile-N and char-N to NO_X formation from a low-capacity bituminous coal-fired industrial boiler

The conversion of fuel-N to NOx is the main contribution of modelling problem arising from coal combustion. This paper NOx from coal-fired industrial boilers and is the least-studied summarises the current understanding of the mechanisms that account for the formation of NOx from fuel-N during coal combustion. Further experimentation on NOx emissions during bi- tuminous coal combustion was simulated with attention focused on the contribution of char-N and votatile-N to fuel-NOx through the Coal/Char combustion method. The critical analysis of this issue allowed for the identification of uncertainties and produced well-founded conclusions. The results indicated that fuel-NOx formation was a very complex physical-chemical pro- cess involving many competing mechanisms. These mechanisms included chemical reactions, convective mass transfer, heat transfer, adsorption and desorption. The contribution of char-N in this experiment varied between 30% and 70%. There may be a slight question as to the exact identity of the main contributor to fuel-NOx, and no definitive conclusion can be made as of yet This uncertainty is because the contribution of char-N to fuel-NOx was heavily affected by the combustion conditions and the contribution of char-N increased monotonically as temperature increased. There was a critical point in the relationship between particle size, air flow, 02 concentration and the contribution of char-N. The contribution of char-N increased with the increase of particle size and air flow initially when less than the critical value, and decreased when more than thecritical value. The contribution of char-N initially decreased when the 02 concentration was increased from 10% to 15% and increased more with the further increase in 02 concentration.