氯添加对燃煤过程中汞析出规律的影响

首先利用管式炉对燃煤及燃煤加氯后煤中汞排放进行研究,结果表明,对于神混煤而言,原煤燃烧后烟气中单质Hg^(0)和氧化态汞Hg^(2+)的比例分别为74.3%、25.7%。添加Cl后,烟气中Hg^(2+)的比例有所上升,当加氯量为0.015%、0.030%和0.045%时,烟气中Hg^(2+)的比例分别上升为32.7%、36.1%和40%,随加氯量的增加,其对汞的氧化作用也随之增强。在现场工程示范试验中,利用脱硫废水中的氯氧化烟气中的汞,以达到脱硫废水与烟气中的汞协同脱除的目的。结果表明,随着脱硫废水喷洒煤的量越大,进入SCR烟气中Hg^(2+)比例增大,经过SCR后Hg^(2+)的比例随之增大。由于飞灰对Hg^(2+)的吸附能力较Hg^(0)强,电除尘系统的脱汞效率提高,但脱硫废水喷洒煤对湿电除尘系统的脱汞效率影响不大。总之,脱硫废水喷洒量越大,燃煤机组烟气净化设备对汞协同去除效率也随之提高。

燃煤加氯影响烟气中汞形态转化规律及汞-氯反应机理的研究

为了解决燃煤加氯后汞形态转化规律不明的问题,采用了理论与实验研究相结合的方式进行研究。首先通过热力平衡方程研究了煤加不同质量分数氯在燃烧过程中汞形态随温度升高的变化,其次在管式炉中进行了燃煤加不同质量分数氯促进汞形态转化的实验,最后采用量子化学计算的方式,通过密度泛函模块B3LYP与赝势基组SDD组合研究3个汞-氯基元反应,获得各个基元反应反应物、过渡态与产物间的能垒,并在此基础上明确3个基元反应的反应过程,对5个温度点下各个反应的化学反应速率进行计算。结果表明:氯添加量的增加,不仅提高了氯化汞的含量,而且氯化汞作为稳定相的范围也随之增大。原煤在分别添加0.015%Cl、0.030%Cl和0.045%Cl后,烟气中氧化态汞比例由24.0%分别提高至25.6%、27.0%和27.7%,与热力学模拟结果实现了相互印证。通过化学反应速率计算,拟合得到各反应在298~1500 K温度范围内反应速率常数的表达式,可为后期工程应用提供较为精准的理论指导。

添加CaCl_(2)对烟气净化装置联合脱汞的规律分析

煤炭燃烧向大气中排放了大量汞。为了探究经济有效的汞排放控制方法,在管式炉中进行了CaCl_(2)晶体的水解实验,CaCl_(2)在一定温度和气氛下会水解产生HCl, HCl有利于烟气中Hg0的氧化。且随着反应温度的增加,水解率呈上升趋势。在流化床炉中进行了CaCl_(2)溶液蒸发协同脱汞实验。CaCl_(2)溶液喷洒在燃煤中可显著提高SCR脱销装置对Hg0的氧化率;煤中喷洒CaCl_(2)溶液可提高烟气中Hg^(2+)的浓度和占比,从而提高湿法烟气脱硫装置(WFGD)对气态Hg的脱除效果。相比于喷洒在原煤中,将CaCl_(2)溶液喷洒在布袋除尘器(FF)前的蒸发干燥塔中,可显著提高FF脱除Hg的效果。整体上看,当温度越高,氯添加比越高时,烟气净化装置协同脱汞的效率也越高。

Synergistic improvement of perovskite film quality for efficient solar cells via multiple chloride salt additives

Perovskite crystal film quality is critical for obtaining efficient perovskite solar cells. Anti-solvent processing was used for fast crystallization of perovskite precursor film, which can form dense perovskite film. However, the crystals from this method are usually small due to the fast crystal growth process, which could lead to grain boundary recombination. Here, element chloride is introduced to enhance the perovskite layer crystallinity via slowing down the perovskite crystallization process by simultaneous introduction of methylammounium chloride （MACI） and cesium chloride （CsCl） into precursor solution. As a result, we achieve high quality of pin-hole free perovskite film with large crystal size. A power conversion efficiency of 21.55% with free of hysteresis of the device is obtained, which is among the highest efficiency of planar structure perovskite solar cells.

Realizing over 10% efficiency in polymer solar cell by device optimization

The low band gap polymer based on benzodithiophene(BDT)-thieno[3,4-b]thiophene(TT)backbone,PBDT-TS1,was synthesized following our previous work and the bulk heterojunction(BHJ)material comprising PBDT-TS1/PC71BM was optimized and characterized.By processing the active layer with different additives i.e.1,8-diiodooctane(DIO),1-chloronaphthalene(CN)and 1,8-octanedithiol(ODT)and optimizing the ratio of each additive in the host solvent,a high PCE of 9.98%was obtained under the condition of utilizing 3%DIO as processing additive in CB.The effect of varied additives on photovoltaic performance was illustrated with atomic force microscopy(AFM)and transmission electron microscope(TEM)measurements that explained changes in photovoltaic parameters.These results provide valuable information of solvent additive choice in device optimization of PBDTTT polymers,and the systematic device optimization could be applied in other efficient photovoltaic polymers.Apparently,this work presents a great advance in single junction PSCs,especially in PSCs with conventional architecture.