Biogas compression and storage system for culinary applications in rural homes

Abstract-

A project is undertaken by the College of Engineering, Bhubaneswar, Odisha, India, to design and develop a biogas production, purification, compression and storage system suitable for use as cooking gas in rural households. Biogas is produced in a floating drum digester by anaerobic digestion of kitchen waste and collected by elastic balloon. A foot lever compressor has been designed, which allows users to stand and compress using a foot lever and valve system. The final prototype is capable of compressing biogas to approximately 4bar in a 0.5m3 tank. In addition to the compressor, a container with silica gel is used to remove water vapor from the Biogas and there is also a fiber container with steel wool to act as a hydrogen sulfide purifier in line with the biogas entering the compression system. . . The result showed that the system could compress biogas in a container, with a pressure of 4 bar and an operating time of 30 min.

Introduction

Biogas is becoming an increasingly important energy source for rural areas in developing countries due to easily available organic waste such as kitchen waste. Biogas has an advantage in terms of low-cost sustainable energy. Biogas is a suitable alternative to traditional solid and gaseous cooking fuels used in developing rural communities. Biogas digester is used to collect kitchen waste and convert it into biogas through anaerobic digestion processes. Biogas is a clean-burning, renewable fuel that contains 50-60% methane and can be used in home cooking applications. Without a suitable compression method, the gas remains in large volume and is difficult to transport and store.
The aim of the project is to design a system to compress and store biogas in a way that is suitable for cooking gas in rural communities. For compressing biogas, we designed a piston and cylinder system, i.e. a modified bicycle pump which is the best compression method due to its low cost and can reach the required pressure in a short time. We take an air tank which is the suitable storage container for biogas.

Biogas compression and storage system for culinary applications

Need for compression and storage of Biogas
Large quantities of kitchen waste are available in rural households. But no effort has been made to utilize these wastes for energy production purposes. An effort has been made to utilize this Biogas as a cooking source with the help of biodigesters. Due to the smaller size of the plants and inadequate management, gas output was limited and irregular. It was always considered only as an alternative stand by agreement. Therefore, a compression and storage system was proposed to use biogas from digesters. Biogas is purified, compressed and stored in LPG cylinders, which makes it easier to transport for use.

Compression mechanism
The design is established as an inclined “foot pump” mechanism using bicycle pumps

foot compressor
Our project aims at a high-pressure gas storage system in a pressure vessel for storing compressed gas as low-cost energy. A stand-up compressor is built for portable service and is different from the common type of reciprocating compressor. This compressor has its smallest single stage capacity size to deliver 0.015m3/min and the delivery pressure is up to 4bar.

Working principle
The pedal compressor design includes two cylinders that are supported by a simple structure, based on the pedal-operated design (Fig.5). With this design, the container is kept stationary, stable and the cylinders move with the lever. The lever arm acts to give mechanical advantage and moves the two pistons through the cylinder body. The two cylinders are used with on-off valves to compress the biogas alternately. The valve system connects the two cylinders and allows variable operation of the system. The cylinders are connected in parallel and each has two valves. One of these valves controls the flow from the storage balloon, the other controls the flow of biogas to the inlet of the storage tank. Once the tank contains enough compressed gas, compression will become difficult and some of the cylinders may be disengaged to facilitate pumping. To disengage a cylinder, the biogas valve must be placed in the “off” position so that the biogas is not drawn into that branch of the system.

Conclusion
Our research work proves that the biogas production, compression and storage system is a profitable venture for rural households where large quantities of kitchen waste are available. It has been proven that biogas can be compressed, stored in LPG cylinders and transported. To make biogas suitable for culinary applications, it is compressed to 4 bar after purification, moisture removal and filled into LPG cylinder. In addition to energy production, the biogas plant also provides organic fertilizer and is useful in dealing with the problems of waste disposal and pollution-free environment. We have determined that the most viable compression method is a bicycle pump. We also determined that a standard air tank is ideal for this application because it is readily available, less expensive, portable, with standard accessories, and resists biogas corrosion. Our final design was manufactured using very simple and conventional construction processes. It was built in a very short time of 2 to 3 days. Furthermore, the cost of our final prototype is around Rs.3,000/when assembled without the biogas digester.

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Biogas compression and storage system for culinary applications in rural homes