Research Article
Vehicular Quality Biomethane Production from Biogas by Using an Automated Water Scrubbing System
Table 1
Comparison of different methods of methane enrichment in biogas.
| | Sl. No. | Method | Advantages | Disadvantages |
| | (1) | Absorption in water | One of the easiest and cheapest methods for CO2 removal. Recommended for rural application. | Water pumping load is high and some loss of methane with washing water. | | (2) | Absorption by chemicals | The chemical absorbents are more efficient in low pressure and can remove CO2 to low partial pressures in treated gas. | Regeneration of the solvent requires a relatively high energy input. Disposal of by-product formed due to chemical reactions is a problem. | | (3) | Pressure swing adsorption | By proper choice of the adsorbent, this process can remove CO2, H2S, moisture and other impurities. | Adsorption is accomplished at high temperature and pressure. Regeneration is carried out by vacuum. It is a costly process. | | (4) | Membrane separation | Modular in nature and separate CO2 and CH4 effectively. | High pressure requirement. The processing cost is also high. | | (5) | Cryogenic separation | Allows recovery of pure component in the form of liquid, which can be transported conveniently | High cost involved makes it impractical for biogas applications. | | (6) | Chemical conversion | Extremely high purity in the product gas. | Process is extremely expensive and is not warranted in most cases of biogas applications. |
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