What is waste gasification?

What is waste gasification?

Waste gasification uses domestic waste as fuel to produce electricity, heat and other consumer goods.The waste used in the waste gasification process is municipal solid waste (MSW). MSW includes solid waste from apartment buildings, households, commercial establishments and educational institutions collected by various local authorities. The waste-to-energy process is a form of energy recovery and there are two main methods.

1.incineration by direct combustion of MSW using large amounts of air.

2.gasification by thermal treatment (usually at temperatures above 700c) to convert the MSW into syngas (synthetic gas).

What is the process of waste gasification?

The gasification process begins with the collection of municipal solid waste (MSW). Garbage trucks transport the MSW to the gasification plant where it is disposed of in a waste storage area, waiting to be used as fuel. The waste is transferred from the waste storage to the area where the thermal treatment will take place. At the heat exchange point, the process generates two types of energy: steam and syngas. The syngas is then processed. Finally, the clean syngas is transferred to a gas turbine to generate electricity.

What are the advantages of waste gasification?

1.waste gasification reduces landfill volumes, fees and disposal costs: Landfills are still the most common way to dispose of municipal and industrial waste. While the recycling rate of waste is steadily increasing, the overall volume of waste is also steadily increasing. The cost of disposing of waste is high – in the United States, the average cost of landfilling is $50/ton, a cost that has steadily increased from $8/ton in 1985 and shows no sign of decreasing. This means that corporate and municipal budgets are increasing, and landfills are getting higher and higher.  Waste gasification offers an opportunity to divert waste from landfills and use it for clean energy production, preventing landfill growth and reducing landfill costs.

2.Syngas combustion for power generation: As organic materials such as MSW and Biomass are gasified, the chemical process produces clean syngas, a fuel that can be used like natural gas. In contrast to other renewable energy methods such as combustion or incineration, the gasification process allows the syngas to remove pollutants before use. Incineration plants do attempt to clean their emissions, but it is done “after combustion, so it is more difficult to capture and sequester harmful emissions.

3.Reducing CO2 and greenhouse gas emissions: waste gasification can be one of the tools we need to shift to a low carbon economy. In particular, the gasification process does not release greenhouse gases as landfills and incineration do. When waste enters a landfill, it releases large amounts of methane as it decomposes. If this methane is not captured, it enters the air 30 times – 3,000 percent – as a more efficient heat-absorbing gas. The landfill process also requires large numbers of trucks to transport waste, which also contributes to its greenhouse gas emissions. If gasification plants can use waste that is readily available nearby, they can also reduce trucking emissions.

4.Prohibition of combustion or incineration: In gasification, the input waste is not a fuel but a feedstock for a high-temperature chemical conversion process.  Gasification has several advantages over traditional combustion processes used for waste treatment, including the fact that it occurs in a low-oxygen environment, limiting the formation of dioxins and significant amounts of SOx and NOx. Gasification is preferred over incineration because there is no combustion in the process and toxic emissions are significantly reduced.

5.The by-product is a valuable high carbon biochar: Another benefit of gasification is that it can output two usable materials. The first, the clean syngas mentioned earlier. The second, “biochar”. In downdraft gasification, 85% of the input waste is converted to syngas. 15% is turned into biochar, which can be used again.

6.Energy efficiency: Gasification allows for an upgrade of renewable energy methods. On average, a conventional renewable energy plant using mass incineration burning can convert one ton of waste into about 550 kWh of electricity.  With gasification, a ton of waste can be used to produce up to 1,000 kWh of electricity. If this waste were to be thrown into a landfill, we would certainly lose a lot of the energy it contains.

How does gasification compare to conventional incineration?

Gasification is considered a cleaner alternative to incineration because the latter uses air to burn municipal solid waste (MSW), which creates pollutants that must be cleaned up to avoid release into the environment. In addition, the ash left behind after incineration must be handled with care because it can be toxic. Gasification does not burn MSW, but rather breaks down its molecules through heat to produce syngas, which is similar to natural gas and can be burned to produce electricity (syngas combustion is a cleaner energy option than fossil fuel combustion).

Gasification gives us huge energy benefits – we can recover more energy while powering a cleaner world.