发电厂烟气开采天然气水合物过程能效模拟

发布时间：2018-09-07 13:48

【摘要】：利用发电厂烟道气(以下简称烟气,主要成分为CO_2与N_2)开采天然气水合物(以下简称水合物)是一种安全、环保的方法,但目前对于该开采方法的能耗及能效情况仍缺乏深入的研究。为此,建立了一种烟气开采水合物的流程:烟气通过增压注入到水合物储层,储层中的水合物一部分发生热分解,另一部分与烟气置换得到CH_4-CO_2-N_2混合气,再经膜组件分离除去N_2得到提浓后的CH_4-CO_2混合气,最后将CH_4-CO_2混合气输送至原发电厂发电。进而采用Aspen Plus软件对这一过程进行了模拟,分析了不同注入压力下烟气置换过程的采注比、置换采出CH_4的比例以及整个过程的能耗与能效。结果表明:(1)烟气开采水合物过程的主要能耗在增压注入阶段,注入压力的增加会导致增压阶段与膜分离阶段的能耗相应增加,但在一定程度上也可提高压力能回收率;(2)注入压力在5~16 MPa条件下,烟气置换过程的采注比为0.03~0.26,置换采出CH_4的比例为19.9%~56.2%,烟气开采水合物全过程的单位能耗为2.15~1.05(k W·h)/kgCH_4,能源投入回报值(EROI)介于7.2~14.7。结论认为:在5~10 MPa范围内增加注入压力可有效地提高烟气开采水合物过程的能效。
[Abstract]:It is a safe and environmentally friendly method to exploit natural gas hydrate (hereinafter referred to as hydrate) by using flue gas of power plant (hereinafter referred to as flue gas, mainly composed of CO_2 and NST2). However, the energy consumption and energy efficiency of the mining method are still lack of in-depth research. In this paper, a process of gas hydrate extraction is established: the gas is injected into the hydrate reservoir by pressurization, one part of the hydrate in the reservoir is decomposed, and the other part is replaced with the flue gas to get the CH_4-CO_2-N_2 mixture gas. Then the enhanced CH_4-CO_2 mixture is obtained by separating the N\ -2 from the membrane module, and finally the CH_4-CO_2 mixture is transported to the original power plant for power generation. Then the process is simulated by Aspen Plus software, and the ratio of gas injection to injection, the ratio of CH_4 produced by replacement, and the energy consumption and energy efficiency of the whole process are analyzed under different injection pressure. The results show that: (1) the main energy consumption in the gas hydrate extraction process is at the booster injection stage, and the increase of the injection pressure will result in a corresponding increase in the energy consumption in the pressurization stage and the membrane separation stage. However, to some extent, the recovery rate of pressure energy can also be increased. (2) the injection pressure is 5 ~ 16 MPa, In the process of flue gas replacement, the ratio of recovery and injection is 0.03 ~ 0.26, the ratio of CH_4 produced by replacement is 19.9 and 56.2, the energy consumption per unit of the whole process of gas hydrate mining is 2.15 ~ 1.05 (k W h) / kg Ch _ 4, and the return value of energy input (EROI) is between 7.2 ~ 14.7. It is concluded that increasing the injection pressure within the range of 5 ~ 10 MPa can effectively improve the energy efficiency of the gas hydrate extraction process.
【作者单位】：华南理工大学化学与化工学院·传热强化与过程节能教育部重点实验室;
【基金】：国家自然科学基金项目“快速可逆天然气水合物储存水凝胶体系构建及其过程强化研究”(编号:51576069) 国家重点研发计划项目“海洋天然气水合物试采技术和工艺”(编号:2016YFC0304006)
【分类号】：TE37

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