Department of Automobile Engineering, Hindustan Institute of Technology and Science, Rajiv Gandhi Salai, Padur, Chennai, Tamil Nadu, 603103, India.
Department of Automobile Engineering, Madras Institute of Technology, Chennai, Tamil Nadu, 600044, India.
Environ Sci Pollut Res Int. 2020 Sep;27(26):32229-32238. doi: 10.1007/s11356-019-07327-9. Epub 2019 Dec 21.
Diesel engines are the most extensively used power source in automobiles and stationary power generation. The main drawback of using diesel engines is that it liberates a significant amount of NOx and PM emissions in the exhaust. NOx emission has a serious effect on the environment, and it has to be controlled effectively. SCR is the most widely used after-treatment technology to control NOx emission, but it has various disadvantages like ammonia slip and degradation of the catalyst. In this study, electrochemical decomposition of NOx is proposed for the simultaneous control of NOx, HC, and CO emissions in a diesel engine. In this work, ionically conducting ceramic electrochemical cells are investigated for control of diesel exhaust emissions. The electrochemical cell consisting of yttrium stabilized zirconia (YSZ) substrate plates as electrolyte and Ag-YSZ and NiO-YZS as an electrode material. The decomposition of NOx in an electrochemical cell is attained by passing electric current. A 2V supply of power was sufficient for effective operation of the electrochemical cell in all load conditions. All the experiments were conducted in a single-cylinder diesel engine. It is observed that the electrochemical cell shows high NOx decomposition rate of 80% at the exhaust temperatures between 350 and 400 °C. The HC reduction up to 65% and CO reduction up to 45% was observed with this technique. The power required to operate the electrochemical cell was low. The electrochemical NOx reduction is relatively simple technology with reduced complexity. From the experiment, it is observed that this concept works efficiently in the oxygen-rich diesel exhaust.
柴油机是汽车和固定式发电中应用最广泛的动力源。使用柴油机的主要缺点是它会在废气中释放大量的氮氧化物和颗粒物排放。氮氧化物排放对环境有严重影响，必须有效控制。SCR 是控制氮氧化物排放最广泛使用的后处理技术，但它存在氨泄漏和催化剂降解等各种缺点。在本研究中，提出了电化学分解 NOx 来同时控制柴油机中 NOx、HC 和 CO 的排放。在这项工作中，研究了离子导电陶瓷电化学电池来控制柴油机废气排放。该电化学电池由氧化钇稳定的氧化锆（YSZ）基板作为电解质，以及 Ag-YSZ 和 NiO-YZS 作为电极材料组成。通过电流通过来实现 NOx 在电化学电池中的分解。在所有负载条件下，2V 的电源供应足以使电化学电池有效运行。所有实验均在单缸柴油机上进行。结果表明，电化学电池在 350 至 400°C 的排气温度下表现出 80%的高 NOx 分解率。该技术可将 HC 减少 65%，CO 减少 45%。运行电化学电池所需的功率较低。电化学 NOx 还原是一种相对简单的技术，复杂性降低。从实验中可以看出，这个概念在富氧的柴油机废气中能有效工作。
