| 污水管道增强通风作用下氧气气液传质特性 |
| 摘要点击 1580 全文点击 525 投稿时间：2021-07-09 修订日期：2021-09-19 |
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| 中文关键词 污水管道 增强通风 污水流速 气相风速 氧气传质 |
| 英文关键词 sewage pipelines enhanced ventilation sewage flow rate wind speed oxygen mass transfer |
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| 中文摘要 |
| 污水管道的厌氧环境是诱发H2S和CH4等有毒有害气体产生的主要原因，结合我国污水收集系统内建筑排水立管与市政污水管道之间设置化粪池加剧了污水管道通风不畅的现状，提出将建筑排水立管与污水管道直连形成的增强通风系统能够有效提高污水管道通风量，来改善管道气相空间环境.在此基础上，结合实验和计算流体动力学（CFD）仿真方法，以污水管道内污水流速和气相风速为出发点，对污水管道内不同污水流速和不同气相风速条件下氧气气液传质规律进行探究，旨在寻求增强管道内氧气传质的方法，实现长期抑制管道内厌氧环境，达到长久控制污水管道有害气体的目的.结果表明，增强气液两相流速均能强化氧气气液传质的能力，气液流速平均每增加0.1 m·s-1，氧体积传质系数KLa增加3.5×10-4 min-1；而较快的污水流速会降低水力停留时间，既而缩短氧气的两相传质时间，整体促进效果不如增强管道内气相风速.同时，以抑制H2S产生的污水溶解氧浓度为评价指标，气相风速平均每增加0.1 m·s-1，有效控制H2S的溶解氧管段长度增加25 m. |
| 英文摘要 |
| The anaerobic environment of sewers is the main cause of the production of toxic and harmful gases such as hydrogen sulfide and methane. The installation of septic-tanks between the drainage standpipes and municipal sewage pipes has aggravated the current situation of poor ventilation in sewage pipes. A system of enhanced ventilation has been formed. By connecting the drainage standpipes and sewage pipes, the system of enhanced ventilation can ameliorate the ventilation of sewage pipes and improve the gas-phase space environment. The experimental and computational fluid dynamics (CFD) simulation methods were established to explore the law of oxygen gas-liquid mass transfer under the different sewage flow rates or wind speeds. This study aimed to seek a method to enhance the oxygen mass transfer, suppress the anaerobic environment, and achieve the purpose of long-term control of harmful gases. The results showed that increasing the gas-liquid flow rates can accelerate the oxygen mass transfer, and the volumetric mass transfer coefficient increased by 3.5×10-4 min-1 for every increase of 0.1 m·s-1. However, the faster sewage reduced hydraulic retention time. The mass transfer time of oxygen was also shortened, and the promotion effect was not as good as that by enhancing the gas velocity in the pipelines. At the same time, when the average gas velocity increased by 0.1 m·s-1, the lengths of pipes where dissolved oxygen could effectively inhibit H2S increased by 25 m. |
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