摘要
沼气的主要成分是CH4和CO2,将CO2从混合气中分离得到的高纯度甲烷气被称为生物天然气。生物天然气可以直接作为石化天然气的替代燃料。人类对天然气需求量的增加推动了生物天然气技术的发展。该文分析了沼气与天然气特性的差别及沼气提纯后替代天然气的可能性,综述了沼气提纯的方法进展,这些方法包括加压水洗、化学吸收法、变压吸附法(pressure swing adsorption,PSA)、膜分离法、低温分离法和甲烷原位富集等技术,其中加压水洗法和PSA法由于在技术和经济方面的综合优势成为目前商业化利用率最高的两项技术,膜分离技术在降低提纯成本和简化提纯系统方面的性能使其成为具备良好发展前景的技术,甲烷原位富集技术在利用高固含率原料生产生物天然气方面具有优势。该文对中国生物天然气技术的发展能够提供有价值的参考。
Biogas can be upgraded to biomethane, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. Upgrading of biogas has gained increased attention due to rising oil and natural gas prices and increasing targets for renewable fuel quotes in many countries. This paper analyzes the possibility of the substitution of natural gas by biogas according to the characteristics and components of biogas and natural gas, and reviewed the biogas upgrading technologies including water scrubbing, organic physical scrubbing, chemical scrubbing, pressure swing adsorption （PSA）, membrane separation, cryogenic upgrading, and the in situ methane enrichment processes. Among these upgrading technologies, water scrubbing and PSA are the main two processes from the point of view of commercialization, because of their comprehensive advantages in technical and economic aspects. Water scrubbing is a very simple process. In a scrubber, CO2 and H2S dissolve into the water, while CH4 does not because of their difference in solubility. PSA is the second most employed technique. In PSA processes, biogas is compressed to a vessel where it is put in contact with an adsorbent that will selectively retain CO2 . In a similar manner to water scrubbing, it is possible to use chemicals to absorb CO2 . However, chemical scrubbing may have higher energetic penalties since the CO2 removal in biogas is a bulk removal process. Membrane separation technology is an excellent technology with good prospects for separating CO2 and CH4. Owing to its superiority in upgrading cost and simplifying upgrading equipment, in situ methane enrichment technology is relatively simple, and there is no need for much auxiliary equipment. Therefore, it has a potential for a lower upgrading cost compared to other techniques, especially when it is used in a biogas plant with high concentration solids as materials. Furthermore, research and application of new materials on biogas upgrading technologies h
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2013年第17期1-8,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家公益性行业(农业)科研专项(201303099)
关键词
沼气
天然气
进展
提纯
biogas
methane
reviews
upgrading
