Plasma Gasification

FAQ

What is Plasma?
Plasma can be described as a gas to which a specific amount of energy has been added to separate the gas component molecules into a collection of ions, electrons, charge-neutral gas molecules, and other species in varying degrees of excitation. Depending on the amount of energy added, the resulting plasma can be characterized as thermal or non-thermal.

What is Gasification?
Gasification is the process for conversion of carbonaceous material into synthesis gas or Syngas.

What is Syngas?
Syngas or synthesis gas comprises primarily of Carbon Monoxide (CO), Hydrogen (H2) and other trace gases. Its composition and calorific value depends on the feedstock characteristics.

What is Plasma Gasification?
Plasma Gasification is the process of using high energy plasma arc technology generated by plasma torches to gasify carbonaceous feedstock producing Syngas and molten inert slag.

Isn’t this Incineration?
The Plasma Gasification process occurs in a controlled low oxygen environment. Waste is gasified directly into Syngas, not burnt. By contrast, incineration occurs in an oxygen rich environment needed to support burning,and leaves harmful by-products such as CO2 and soot.

What other components are produced from the Plasma Gasification process?
The carbonaceous material is gasified into Syngas. Inert components such as ash, metals and other inorganic material forms a molten slag within the gasifier.

What type of waste can be processed with Plasma Gasification?
The Plasma Gasification process is able to handle many types of waste ranging from unsorted Municipal Solid Waste (MSW), industrial waste, medical and toxic waste and biomass.

What about Municipal Solid Waste?
Municipal Solid Waste, unsorted or sorted, can be processed by a Plasma Gasification Plant. To improve the efficiency of the process, MSW may be pre-sorted to remove inert material and dried to remove excessive moisture before it is fed into the Plasma Gasification reactor.

What about the acid gas and other toxic emissions from the destruction of plastics in MSW such as PVC etc.?
The Plasma Gasification process is the best solution for PVC & Plastics.  The extremely high temperature within the Plasma Gasification reactor breaks down the plastics to produce CO, H2, CO2 and HCl. Unlike incineration, this process does not produce free chlorine radicals which is main culprit in formation of dioxins and furans.

Is there any ash produced from Plasma Gasification?
There is no ash produced in the Plasma Gasification process. Inert and inorganic material including ash content of the feedstock forms the molten slag which is removed and vitrified. In addition, any suspended particles in the Syngas stream will be filtered in the gas cleaning process stream and returned to the Plasma Gasification reactor to be vitrified.

What about toxic by-products such dioxins and furans?
The extremely high temperature present within the Plasma Gasification reactor (5,000 to 10,000ºC) does not promote the formation of dioxins and furans. In fact, it destroys the dioxins and furans.

Is a Plasma Gasification plant more expensive compared to Incineration Plant?
The cost of a Plasma Gasification plant is comparable and can be cheaper than an incineration plant. In addition, the Plasma Gasification plant does not require supplementary fuel in the gasification process.
Incinerators may require supplementary fossil fuel or natural gas to sustain the burning process for feedstock with high moisture content. Overtime, this translates into a significant operation expense for the incineration plant.

What are the operational conditions of a Plasma Gasification plant?
The typical operational hours of a Plasma Gasification plant are around 7,500 hours per year based on 24 hour operation and 7 days per week. An operational maintenance shutdown is required to perform preventive maintenance on the Plasma Gasification plant systems.

What is the application for the Syngas?
The Syngas produced from the Plasma Gasification process is a low BTU gas, meaning it can be combusted in a gas turbine or gas engine in a power plant to generate electricity. In addition, Syngas can also be processed in widely used and established industrial chemical or biological processes to produce biofuels such as fuel oil and ethanol.

How is this considered Renewable Energy?
The Plasma Gasification plant processes and consumes waste which will otherwise be burnt or buried inside a landfill. Stored chemical energy within the waste is “unlocked” and converted  into Syngas, a form where this energy can be utilised more efficiently.

Don’t the plasma torches consume a high amount of electrical energy?
Depending on the feedstock characteristics, the Plasma Gasification plant is typically able to generate sufficient electrical power for its internal use as well as surplus power for export and sale to the grid.

Are there any operational Plasma Gasification plants?
There are several Plasma Gasification plants operating throughout the world processing waste. In Japan, since early 2000, 2 plants operated by Hitachi Metals have been processing up to 200 tonnes-per day of ASR (Auto Shredded Residue) and Municipal Solid Waste mixture. In India, 2 plants are currently operating with each processing 68 Tonnes per day of hazardous waste to energy.

How does using Plasma Gasification technology for generation of electrical power from MSW overcome the fossil fuel problem?
A Plasma Gasification plant processing 500 tonnes-per-day of Raw MSW with an input calorific value of 1,900kCal/kg is able to produce approximately 13 - 15 MWe electric power (depending on whether flue gas energy recovery is integrated) and an additional 6,000,000 kcal/hr of thermal energy from the enthalpy of the hot syngas exiting the plasma reactor.

What are the environmental benefits?
• Utilises waste which will otherwise be disposed of by conventional means such as landfilling.
• Produces renewable fuel that supplements or replacess rapidly depleting and polluting fossil fuel.
• Completely and efficiently destroys wastes and pollutants without leaving behind hazardous residues or harmful emissions.
• Reduces the emission of landfill gases (primarily methane) from decomposition of landfilled waste.