NHCs梯度代谢模型及其在固定床煤气化废水“零排放”过程综合中的作用机理

Coal to SNG is an effective way to relieve the shortage of nature gas in China and has broad application prospects. However, the development of coal to SNG is hindered by the requirement of wastewater zero liquid discharge (ZLD). How to allot the treatment efficiency of nitrogen heterocyclic compounds (NHCs) for different units in a high efficiency and low cost way is key to realize fixed-bed coal gasification wastewater treatment process.. The migration, transformation, circulation, accumulation of the characteristic pollutants NHCs in the unit and system are studied to determine the key nodes and control units of NHCs treatment in fixed-bed coal gasification wastewater ZLD process and reveal the rules of gradient metabolism of NHCs. The functional relationship between economic performance and metabolic rate and metabolic limit of NHCs is established. A multi-objective optimization model of technical indicators, treatment costs and carbon emissions is established to realize low-carbon and high-efficiency process synthesis of coal gasification wastewater treatment process. In this project, the nitrogen transport and transformation of fixed-bed coal gasification wastewater are studied from the perspective of NHCs degradation rate (kinetics) and conversion limit (thermodynamics). It is expected to reveal the metabolism regularity of nitrogen in the ZLD process and to establish a multi-objective regulation mechanism for wastewater ZLD process.

煤制天然气是缓解我国天然气短缺的有效途径，应用前景广阔，然而受到废水“零排放”的制约，难以快速发展。在固定床煤气化废水处理过程中如何高效、低成本的统筹系统中各处理单元间含氮杂环化合物（NHCs）的处理效能是煤气化废水“零排放”的关键。. 项目通过对废水的特征污染物NHCs在单元与系统中迁移、转化、循环、累积的研究，确定固定床煤气化废水“零排放”过程中NHCs处理的关键节点和控制单元，揭示NHCs的梯度代谢规律；通过确定NHCs代谢速率、代谢限度与经济性能的函数关系，建立技术指标、处理成本、碳排放的多目标优化模型，实现低碳高效的煤气化废水“零排放”过程综合。从NHCs降解代谢速率（动力学）与转化极限（热力学）角度对固定床煤气化废水的氮元素迁移与转化进行研究，有利于建立废水“零排放”过程多目标调控机制，对废水“零排放”的过程综合具有一定的借鉴意义。

煤制天然气是缓解我国天然气短缺的有效途径，但由于受到废水“零排放”的制约难以快速发展。项目重点探究了煤气化过程中如何实现废水的“零排放”，并对相关工艺流程的节能降耗、提质增效进行了研究，主要内容包括：（1）揭示固定床煤气化废水“零排放”中NHCs的梯度代谢规律。实现“零排放”过程综合中技术、经济、环境的多目标优化；（2）提出一种利用煤化工低品位余热的新型串级吸收式热泵系统。综合热力学性能和经济性，采用多目标优化方法对系统进行优化；（3）使用混合萃取剂研究了混合溶剂萃取精馏工艺与部分热耦合技术的经济和环境表现。探讨了混合溶剂萃取精馏工艺与热泵技术相结合的经济性和环保性；（4）模拟有机朗肯循环、吸收式制冷循环和煤制合成气净化相结合的一体化工艺将余热转化为电能、冷能等可用能源。从能源、㶲、经济等方面对该过程进行分析；（5）利用Aspen Plus模拟软件，构建煤制氢和生物质制氢工艺的过程模拟。根据模拟结果，评价两种制氢工艺的经济技术性能。基于生命周期评估（LCA）概念，分析制氢工艺的环境和水资源消耗情况。