Hydrogen Generation from Food Waste

TABLE OF CONTENTS

1. PROJECT TITLE

2. INTRODUCTION

3. AIM

4. METODOLOGY

5. CONCLUSION

REFERENCES

PROJECT TITLE

Programmed Process Control for Stable Bio-Hythane Generation in Two-Stage Thermophilic Anaerobic Assimilation of Domestic Waste.

1. INTRODUCTION

There is expanding global enthusiasm for growing low carbon innovations to give hydrogen sustainability. Hydrogen can be created through dim anaerobic maturation utilizing sugar rich substrates, and methane can be delivered in methanogenic second stage. A stage forward for the common anaerobic assimilation procedure of bio-waste, which gained enthusiasm among the analysts, is said to be the two-stage approach which concluded to the generation of hydrogen in the first phase reactor and methane in the subsequent one. (Martínez-Pérez et al., 2007)

At present, the hydrogen generation by fermentative procedures of starch rich substrates such as bio-waste and food-waste, called as Dark Fermentation (DF) is one of the most encouraging advancements for high return hydrogen creation. A few investigations demonstrated that Dark Fermentation could be combined with Anaerobic Digestion so as to acquire a blend of gases to be utilized independently or combined. (Graham, Rideout, Rosenblatt, & Hendren, 2008)

Talking about this, in recent years a perceptive practice has been developing as a less expensive alternative to the use of chemicals for external control of the pH in the phase of dark fermentation to maintain the pH within the optimal range for the hydrogenase catalysed 0reactions. Therefore, also from an economical point of view, it is convenient to develop a pH control system which allows to manage and optimize the process in a sustainable approach, because neither chemical addition nor high costs devices would have to be used to reach the target. Therefore, this research will deal with the optimization of a two-phase anaerobic digestion process that treats food waste for bio-hythane production without additional external chemicals.

2. AIM

The paper will report the after effects of a long haul pilot scale preliminary where the domestic waste as a sole substrate is to be treated in a two-stage thermophilic anaerobic assimilation process. As the first stage, the hydrogen creation was obtained by recycling the effluent originating from the methanogenic stage without expansion of synthetic substance.

Alkali distribution into the principal stage reactor is a disadvantage of this approach. (Micolucci, Gottardo, Bolzonella, & Pavan, 2014)

This examination will be centered around the improvement of a control protocol dependent on ammonia concentration. The initial segment of this paper will show hoe the utilization of a variable recirculation flow prevents the ammonia inhibition by controlling the entire procedure. So as to set out the foundation for a programmed control of the procedure, in the second piece of the examination a preliminary statistical study is presented. (Micolucci et al., 2014) During the unfaltering state conditions, oversaw by a variable recirculation stream, the framework will deliver a blend of gas that will satisfy the guidelines for the bio-hythane blend in with a normal structure scope of 7% H2, 58% CH4 and 35% CO2. Normal explicit gas creation arrived at 0.69m3/kgTVS and the gas generation rate of 2.78m3/m3rd. (Micolucci et al., 2014)

3. METHODOLOGY

The effluents of the reactor is to be monitored 2 to 3 times per week in terms of total and volatile solids content, chemical oxygen demand, TKN and total phosphorus. The remaining parameters, namely pH, conductivity, volatile fatty acids content and speciation, total and partial alkalinity and ammonia, should be checked daily. All the analyses, except for VFAs, will be carried out in accordance with the Standard Methods. The analysis of the volatile fatty acids has to be carried out with a Carlo Erba™ gas chromatograph equipped with a flame ionization detector (T ¼ 200 ?C), a fused silica capillary column Supelco NUKOL™(15m? 0.53mm? 0.5 mm thickness of the film), while hydrogen is used as carrier gas. The analysis will be conducted using a temperature ramp from 80 ?C to 200 ?C (10 ?C/min). The samples must be analysed before being centrifuged and filtered with a 0.45 mm filter. The production of gas for both reactors will be monitored by two flow meters (Ritter Company™, drum-type wet-test volumetric gas meters). The percentages of methane, carbon dioxide and oxygen will be determined by an infrared gas analyzer portable GA2000™ (Geotechnical Instruments™). The percentage of hydrogen and methane is to be determined by a gas chromatograph GC Agilent Technology 6890N™ equipped with a column HP-PLOT MOLESIEVE™ (30 m x 0.53 m x ID x 25mm thickness of the film), using a thermal conductivity detector (TCD) and Argon as gas carrier. (APHA, 2011)

4. CONCLUSION

This pilot scale study will show that it will be possible to obtain a stable hydrogen production by dark fermentation without physical or chemicals pre-treatments when bio-waste is used as sole substrate

The optimization will be reached with only partial recycle of digested sludge from second reactor (methanogenesis) after a mild solid separation, which will allow to maintain the pH at an optimal level (5-6) for hydrogen evolution in the first reactor (dark fermentation)

A stable Bio-hythane production should be obtained with GPR around 2.78 m3/m3 rd and SGP around 0.69 m3/KgTVSfed

By comparing the predictive capabilities of the models (SDEP) and the economic feasibility, the best model could be found out.

REFERENCES

APHA, A. (2011). WEF, 2011. Standard Methods Online.

Graham, L. A., Rideout, G., Rosenblatt, D., & Hendren, J. (2008). Greenhouse gas emissions from heavy-duty vehicles. Atmospheric Environment, 42(19), 4665–4681. https://doi.org/10.1016/j.atmosenv.2008.01.049

Martínez-Pérez, N., Cherryman, S. J., Premier, G. C., Dinsdale, R. M., Hawkes, D. L., Hawkes, F. R., … Guwy, A. J. (2007). The potential for hydrogen-enriched biogas production from crops: Scenarios in the UK. Biomass and Bioenergy, 31(2–3), 95–104. https://doi.org/10.1016/j.biombioe.2006.07.003

Micolucci, F., Gottardo, M., Bolzonella, D., & Pavan, P. (2014). Automatic process control for stable bio-hythane production in two-phase thermophilic anaerobic digestion of food waste. International Journal of Hydrogen Energy, 39(31), 17563–17572. https://doi.org/10.1016/j.ijhydene.2014.08.136