The technology used here at GREE, to help us achieve our great results is known as Thermoselect.

THERMOSELECT produces from waste of all kinds:

  • synthesis gas for flexible utilisation
  • mineral and metallic raw materials
  • THERMOSELECT emissions values are drastically below the limiting values
  • THERMOSELECT completely destroys dioxins and furans
  • THERMOSELECT facilities are compact, modular and economic

and thus meet the standards and satisfy the claims of sustainable waste disposal:

  • complete feedback of products in the raw materials cycle
  • prevention of toxic residues requiring dumping
  • protection of the landscape and natural resources


The THERMOSELECT process recovers a synthesis gas, utilisable glass-like minerals, metals rich in iron and sulphur from municipal solid waste, commercial waste, industrial waste and hazardous waste in a continuous recycling process by means of high temperature gasification of the organic waste constituents and direct fusion of the inorganic components. Pure water, salt and zinc concentrate are produced as usable raw materials during the process water treatment. Unlike other thermal processes, there are no ashes, slag or filter dusts to be expensively landfilled or passed through secondary treatment.

During the first process step the waste is delivered, without pre-treatment, to a press in which it is compacted, liquids are distributed and residual air is pressed out (removal of the nitrogen ballast). A high compressive force is applied to form gastight plugs from the waste and to press it into a degassing duct.

With increasing heat, the waste is dried, organic constituents are degassed and enter the high temperature reactor. The carbon and carbon compounds produced are gasified under controlled addition of oxygen at temperatures up to 2000°C in an environment rich in water vapour. The following exothermic reactions lead to the formation of carbon monoxide and carbon dioxide.

C + ½ O2 ==> CO C + O2 ==> CO2
2CxHy + (2X+Y/2) O2 ==> 2X CO2 + Y H20

The endothermic Boudouard reaction takes place simultaneously

C + CO2 ==> 2CO

as well as endothermic hydrogen reactions, e.g.

C + H2O ==> H2 + CO
CxHy + X H2O ==> (X+Y/2) H2 + X CO

During a residence time of at least 2 seconds and gas temperatures above 1200°C, chlorinated hydrocarbons, dioxins and furans as well as other organic compounds are reliably destroyed. The main components of the synthesis gas produced are the smallest possible molecules (H2, CO, CO2, H2O). Subsequent shock cooling of the synthesis gas from 1200°C to below 90°C with water prevents reformation of chlorinated hydrocarbons. The synthesis gas passes through multi-stage cleaning, in which the contaminants are absorbed or condensed. The clean synthesis gas is then available as an energy carrier or as a raw material – for example for the synthesis of primary chemical materials such as methanol.

The inorganic metallic and mineral constituents are melted in the high temperature reactor at temperatures up to 2000°C. The molten material is homogenised in a duct connected to the high temperature reactor. Two stable high temperature phases (minerals, metal) are produced at approx. 1600°C. The homogenised molten mass is subsequently shock cooled with water, the metals and minerals separate and are extracted out of the gas sealing water basin as granulate. The separation of the mineral and the metallic granulate takes place outside the system by means of magnetic separation. The quality of the glass-like minerals is equivalent to that of natural products. The metals can be used in metallurgy.

Process water - originating from the waste moisture and the gasification reactions - is treated and then used in the plant as cooling water. Salt, zinc concentrate and sulphur can be reused by industry. All intermediate products produced during the cleaning phases are fed back into the thermal process.