This article is a continuation of our series about various topics in renewable energy. Gasification is the thermal decomposition of organic materials at high temperatures in a limited oxygen environment. The process requires an initial heat supply to produce a combination of combustible gases like methane, hydrocarbons, hydrogen and carbon monoxide. This combination of gases is called ‘syngas’ which can be stored or combusted as it is produced. It is through gasification that biomass to be converted effectively. The most advanced form of gasification can provide for carbon capture which is one way of reducing carbon emissions in successfully combating climate change. Characteristics of Landfill gas: Landfill gas (LFG) is generated in landfills through the decomposition of organic waste materials normally disposed in landfills. LFG is produced when micro organisms in a landfill break down biodegradable waste like paper and food waste. The main components are methane (50%) and carbon dioxide (48%). It is the methane content makes it a prized fuel source. Methane is a greenhouse gas more than 20 times as powerful as carbon dioxide in trapping heat in the atmosphere. LFG’s composition varies with the age of the landfill, weather conditions, characteristics of the waste and other factors. Dangers of Landfill gas: LFG is a grave threat to security, to human health and to global warming. It is dangerous for three reasons: (1) LFG becomes explosive when it escapes from the landfill and it mixed with oxygen, (2) It can replace oxygen in the air in closed spaces, enough to case asphyxiation, and (3) LFG is dangerous if the methane level reaches high enough concentrations to cause a fire or an explosion. Opportunities of Landfill gas: LFG can be an inexpensive resource if local environment regulations necessitate the gas to be extracted and flared away. LFG can help lower the costs of green power when it is combined with solar and wind energy. Electricity from LFG is expected to provide the largest portion of its green power after wind and hydro power. Utilizing Landfill gas: One way to produce energy from rubbish is to utilize landfill gas. Compressed solid wastes create methane gas. This gas can be trapped, piped to a small plant and combusted to turn a turbine and generate electricity. LFG is a low pollutant fuel with regards to emissions of nitrogen oxides, carbon monoxide, unburned hydro carbons and volatile organic emissions. Landfill gas process: Landfill gas is fired in a plant’s boilers creating super heated steam. The super heated steam is used to drive the steam turbine or generator to produce electric power. LFG is collected or extracted from landfills by drilling wells into the landfills and collect the gases through pipes. Once the LFG has been processed, it can now be combined with other natural gases to fuel conventional combustion turbines. In the United States, LFG users are one of the top users of renewable energy in the manufacturing industry sector. Landfill gas opportunities: For many applications, landfill gas can be used as an alternate for natural gas either as a direct source or energy or as a fuel for electric production. Municipalities and other companies have realized the great potential for energy within their reach through the LFG. Landfill trash and garbage generates a naturally occurring gas that can be utilized to displace the conventional fossil fuels.
Plasma gasification is today’s modern technology in eliminating garbage and landfill problems. The process involves the use of a high tech plasma torch to burn waste in a closed, controlled environment with no hazardous emissions. It is said that the process is 2/10th of 1% away from zero waste. One of the byproducts of gasification is hydrogen which can be a separate source of power. Waste disposal continues to be a pressing challenge as population grows, along with numerous industrial developments in many countries around the world. Long ago, residents’ trash was brought and dumped in an isolated place, far enough from the city or village. Today, instead of the open dumping, trash is collected and transported to landfills to be buried. Today, methods such as plasma gasification, incineration, recycling and ocean dumping offer better alternatives. Some of the methods of disposing waste include the following:
- Landfill. This is the most practiced method in the world. More often, landfills are old mining areas and abandoned quarries. It is considered to be the most cost effective way of disposing waste. The wastes are layered into thin spreads, compacted then covered with a layer of earth and more layers are added over time.
- Integrated disposal. Primarily used for municipal waste. The process involves the minimizing of the materials, separating and collecting, then reusing and recycling non organic segment. Organic materials are used for energy and fertilizer.
- Incineration. Sometimes referred to as ‘thermal treatment’, this method involves burning of the trash. This method is used to transform waste into gas, steam, heat and ash.
- Water decomposition. The process involves the removal of the organic materials and decomposes them at high temperature and pressure.
- Recycling. This means taking some of the waste materials and transforming them into new useful products.
- Plasma gasification. This consists of heating the disposed waste to over 10,000 degrees converting these wastes into