Combined ammonia recovery and solid oxide fuel cell use at wastewater treatment plants for energy and greenhouse gas emission improvements
Combined ammonia recovery and solid oxide fuel cell use at wastewater treatment plants for energy and greenhouse gas emission improvements
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DOI：
10.1016/j.apenergy.2019.02.029
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发表时间：
2019-04
期刊：
影响因子：
11.2
通讯作者：
Oliver Grasham;V. Dupont;M. Camargo-Valero;Pelayo García-Gutiérrez;T. Cockerill
中科院分区：
文献类型：
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作者：
Oliver Grasham;V. Dupont;M. Camargo-Valero;Pelayo García-Gutiérrez;T. Cockerill
目前污水处理厂(WWTP)的标准做法包括回收污泥厌氧消化产生的消化液，并将其返回处理过程。然而，需要大量的能量才能使酒中存在的氨得到生物分解。这种生物处理还会排放大量有害的温室气体，使白酒的改道和氨的回收成为改善废水处理可持续性的一个值得注意的选择。这项研究提出了一种新的工艺，从分流的废液中回收氨，用于固体氧化物燃料电池(SOFC)系统，用于污水处理厂。Aspen Plus V.8.8和数值稳态模型已经开发出来，使用来自西约克郡(英国)的一个污水处理厂的数据作为参考设施(750,000p.E.)。Aspen Plus模拟表明，能够回收污水处理厂生产的沼液中82%的氨态氮。回收过程使用一系列的汽提、吸收和闪蒸分离装置，在这些装置中，水与氨一起回收。这有助于在摩尔比为2.5的蒸汽：甲烷摩尔比的燃料电池中进行有效的内部蒸汽甲烷重整。将该工艺安装在污水处理厂作为研究案例，有可能对能源和环境产生重大影响；调查结果表明，处理设施可以从电力净消费国转变为净生产者。SOFC已被证明以48%的电效率运行，NH3贡献了4.6%的功率输出。还证明，污水处理厂每人每年可减少3.5kgCO2E的排放，这是由于生物处理过程中氨的分流所节省的排放量，以及与不依赖电网电力相关的生命周期排放。
Current standard practice at wastewater treatment plants (WWTPs) involves the recycling of digestate liquor, produced from the anaerobic digestion of sludge, back into the treatment process. However, a significant amount of energy is required to enable biological breakdown of ammonia present in the liquor. This biological processing also results in the emission of damaging quantities of greenhouse gases, making diversion of liquor and recovery of ammonia a noteworthy option for improving the sustainability of wastewater treatment. This study presents a novel process which combines ammonia recovery from diverted digestate liquor for use (alongside biomethane) in a solid oxide fuel cell (SOFC) system for implementation at WWTPs. Aspen Plus V.8.8 and numerical steady state models have been developed, using data from a WWTP in West Yorkshire (UK) as a reference facility (750,000p.e.). Aspen Plus simulations demonstrate an ability to recover 82% of ammoniacal nitrogen present in digestate liquor produced at the WWTP. The recovery process uses a series of stripping, absorption and flash separation units where water is recovered alongside ammonia. This facilitates effective internal steam methane reforming in the fuel cell with a molar steam:CH4ratio of 2.5. The installation of the process at the WWTP used as a case of study has the potential to make significant impacts energetically and environmentally; findings suggest the treatment facility could transform from a net consumer of electricity to a net producer. The SOFC has been demonstrated to run at an electrical efficiency of 48%, with NH3contributing 4.6% of its power output. It has also been demonstrated that 3.5 kg CO2e per person served by the WWTP could be mitigated a year due to a combination of emissions savings by diversion of ammonia from biological processing and lifecycle emissions associated with the lack of reliance on grid electricity.