PDF Publication Title:
Text from PDF Page: 006
Table 4. Biogas and biomethane composition. Component Average concentration in the biogas Minimum and maximum concentration in the biogas Average concentration in biome thane Minimum and maximum concentration in the biome thane Figure 4. Composition of the biogas fed in the VSA unit (concentration % V/V). During all the experimental period (90 days), biomethane flow rate and composition were analysed every day once a day, for a period of 1 h. Additionally, a high time resolved analysis (1 measurement per minute for 1 h) was also per- formed, to investigate the effect of each VSA phase on bio- methane quality. Finally, the off-gas of the VSA system was also analyzed. RESULTS Biogas Production The average composition of biogas produced during the 3 months of the testing period is shown in Table 4. Daily variations in biogas composition are shown in Figure 4 for month 1, representative of the whole experimentation peri- od. Results show that biogas composition is very stable through all the experimental time, thanks to the ABR reactor structure. In fact the compartment separation protects the methanogenesis from any pH and feeding variation, or Vola- tile Fatty Acids accumulation in other compartments. Such a biogas source is an ideal stream for the validation of an upgrading system, since it is possible to monitor VSA per- formances in constant biogas feeding conditions. This is an important advantage, since it was recently demonstrated that variations in biogas composition can affect the upgrading efficiency [24]. Regeneration Optimization Table 3 reports the breakthrough times obtained with the different regeneration procedures. The procedure which leads to the higher breakthrough time is procedure D, where the regeneration conditions are pressure 3.00 3 104 Pa, flow rate 6.67 3 1025 Nm3 s21 and regeneration time 600 s. How- ever, procedure A was chosen as the optimal solution, since it leads to a faster regeneration (300 s) while breakthrough time is still acceptable (840 s). It can also be observed that the most important parameter is pressure, since using a vacu- um of 5.00 3 104 Pa instead of 3.00 3 104 Pa (procedure B) led to a significant decrease in regeneration efficiency. Others including nitrogen and hydrogen (1.7 6 0.8) % 0.9–3.5% (0.96 6 0.01) % 0.5–2.8% Methane (48 6 2) % 45.3–51.5% (98.45 6 0.02) % 95.4%–99.2% Carbon dioxide (49 6 2) % 46.7–53.2% (0.060 6 0.003) % <0.1–0.3% Oxygen (2.0 6 0.6) % 1.2–3.1% (0.53 6 0.06) % 0.2–1.5% Figure 5. Breakthrough curves through several adsorption/ desorption cycles, reported as concentration % V/V of carbon dioxide. Figure 6. Daily variations of biomethane purity espressed as concentration % V/V of methane. Figure 5 shows the saturation curves obtained after up to 10 regeneration cycles, using the regeneration procedure A. No significant differences among several cycles can be observed: hence, the possibility to perform a biogas upgrad- ing on these materials was demonstrated to be possible. Biomethane Production The performances of the VSA upgrading system are given in Table 4. Biomethane production rate ranged from 1.42 3 1025 to 1.83 3 1025 Nm3 s21. Methane recovery (defined as the amount of methane in the purified product divided by the total amount of methane fed to the system) was > 95%. A high biomethane purity was obtained (purity average > 98%), suitable for grid injection and use in vehicles, in compliance with most of National standards and legislation, which are resumed in Table 1. Figure 6 shows Environmental Progress & Sustainable Energy (Vol.00, No.00) DOI 10.1002/ep Month 2017 5PDF Image | Vacuum swing adsorption on natural zeolites
PDF Search Title:
Vacuum swing adsorption on natural zeolitesOriginal File Name Searched:
Vacuum_swing_adsorption_on_natural_zeolites.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)