Zenergy PWR waste to energy

The Plasma Waste Recycling (PWR) process uses high-temperature thermal plasma to convert municipal solid waste (MSW) to syngas, molten metal and vitreous slag - there is no ash. Air emissions are said to be lower than the combustion of natural gas and are within US EPA standards.

The syngas is then used to generate renewable electricity which is sold to the power grid. The molten metal is cast as scrap steel and the slag is cast as building material aggregate or spun into mineral wool. All by-products can be sold to generate additional revenue.

MSW is moved directly from the tipping floor pit into a hopper which gravity feeds PWR’s feeder. The reaction is controlled by the feed rate of the MSW into the reactor. The reaction is continuously monitored by sensing the temperature and composition of the syngas exiting the reactor, and the level of molten metal and slag in the reactor.

Because the process involves extremely high temperatures in a sealed vessel under negative pressure, the process is non-combustive and there is no ash residue.

The reactor itself is a refractory-lined steel vessel. The plasma creates the extremely high temperature that converts the organic molecules of the entering MSW by dissociation into syngas composed mainly of carbon monoxide (CO) and hydrogen (H₂) through endothermic reactions. The reactor interior is under negative pressure, which prevents hot gases from escaping to the atmosphere. Since the atmosphere in the reactor is reducing, metals in their metallic state are tapped into ingots as in a foundry. The slag is tapped separately.

The hot syngas exits the reactor and passes through a heat recovery boiler to lower its temperature producing steam for use in generating electricity. The gas is kept at a sufficient temperature to prevent the formation of dioxins or furans. From there it passes through a scrubbing process. The syngas may then be used to generate electricity in a gas turbine combined cycle, a boiler and steam turbine, or a reciprocating engine. The renewable green electricity can be sold to the grid and powers the entire plasma gasification plant.