常见的沼气利用方式是提纯天然气。该方式是把沼气中CO2通过高压水洗、变压吸附、膜分离等技术进行去除,从而将沼气制成CH4纯度更高的生物天然气。制出的生物天然气可经过压力调节后接入城市输气网,也可以压缩后制成车用燃料(CNG),或者制成液化天然气(LNG)出售。
The common way to utilize biogas is to purify natural gas. This method is to remove CO2 from biogas through high-pressure water washing, pressure swing adsorption, membrane separation, and other technologies, thereby making biogas into biological natural gas with higher CH4 purity. The produced biological natural gas can be connected to the urban gas transmission network after pressure adjustment, and can also be compressed into vehicle fuel (CNG), or converted into liquefied natural gas (LNG) for sale.
由于厌氧项目肯定需要热量,所以项目一般还要配套沼气锅炉,一部分沼气用于锅炉,剩余沼气可全部用于沼气提纯。同时还应设置应急火炬,用于沼气净化系统或者沼气利用系统故障时,沼气的应急处理。
As anaerobic projects definitely require heat, projects generally need to be equipped with biogas boilers, with some of the biogas used for boilers, and the remaining biogas can be used entirely for biogas purification. At the same time, emergency flares should also be installed for emergency treatment of biogas when the biogas purification system or biogas utilization system fails.
随着我国双碳计划的提出,氢能变得越来越热,因此沼气重整制氢近几年也被越来越多的提出,同时也有部分项目开始实践。
With the proposal of the dual carbon plan in China, hydrogen energy has become increasingly hot. Therefore, biogas reforming for hydrogen production has been increasingly proposed in recent years, and some projects have also begun to be implemented.
沼气重整制氢,也有多种技术。目前用的多的还是先将沼气进行脱碳提纯,提纯后的气体再进行重整制氢,重整后的混合气体再进行提纯,终得到纯度较高的氢气。
There are also various technologies for reforming biogas to produce hydrogen. Currently, the most commonly used method is to decarbonize and purify biogas, and then conduct reforming of the purified gas to produce hydrogen. After reforming, the mixed gas is purified to ultimately obtain hydrogen with higher purity.
也有学者提出沼气直接重整制氢,即省去沼气脱碳提纯这一步,从技术层面说也是可以的。不过目前我国氢能的应用场景还未构建完全,直接用沼气重整制氢,具有一定的市场风险。从项目规划的角度看,如果是沼气提纯后再制氢,可以先预留制氢场地,后期等氢能有应用场景了再上。
Some scholars have proposed that direct reforming of biogas to produce hydrogen, which eliminates the step of decarbonization and purification of biogas, is also technically feasible. However, at present, the application scenario of hydrogen energy in China has not been fully constructed, and directly reforming biogas to produce hydrogen poses certain market risks. From the perspective of project planning, if biogas is purified before hydrogen production, a hydrogen production site can be reserved for later use when hydrogen energy has an application scenario.