The ProcessThe ENERGOS process is a technically-advanced, well proven technology converting non-recyclable, non hazardous materials into renewable energy.
The process can treat a wide range of waste materials with different compositions e.g municipal solid waste (MSW), residual MSW, solid recovered fuel (SRF)/ refuse derived fuel (RDF) and commercial wastes.
Low and stable emissions
The technology operates with low and stable emission levels, a result of a highly controlled process. The thermal conversion is carried in two stages:
Stage one: Primary chamber where gasification of the waste takes place to produce a synthetic gas.
Stage two: Secondary chamber where the synthetic gas is oxidised at a high temperature.
This highly controlled two-stage process enables a simple dry flue gas treatment system to be employed and eliminates the need for a sophisticated and costly end of pipe flue-gas treatment system.
An ENERGOS plant system consists of the following process stages:
Waste utilised in an ENERGOS plant has to be pre-treated prior to use. This involves shredding the waste and magnetically separating ferrous materials which can be recycled. This pre-treatment can either be carried out at an ENERGOS plant operation or externally before arriving at the plant.
The pre-treated waste (fuel) is then stored in a fuel bunker. The gasification chamber is fed via a fuel-hopper with an automatic crane system. Air from the reception hall is used as process air for the gasification process. This creates a slight negative pressure in the reception hall and eliminates odour.
Thermal conversion (gasification and oxidation)
At each stage of the process a high degree of control is exerted to ensure that emissions to the atmosphere are minimised. As a by-product of the process, bottom ash is discharged from the primary chamber at the end of the grate.
Heat recovery (steam production)
Hot flue gas from the secondary chamber is recovered in the Heat Recovery Steam Generator (HRSG) section of the plant. The HRSG consists of a water-tube boiler, a smoke-tube boiler and an economiser. The HRSG is equipped with a shot-ball system for cleaning the heat transfer surfaces during operation and with a feed-water tank and feed-water pumps.
Air pollution control (Flue gas cleaning)
The ENERGOS process is equipped with a simple, dry, flue-gas cleaning system. This involves the injection of lime and activated carbon, downstream of the economiser. Used lime and activated carbon, together with fly ash, is separated from the flue-gas in a bag house filter. The lime and carbon are supplied from a storage silo and the filter residue is collected and stored in a filter dust silo. The lime adsorbs acid components in the flue-gas, while the activated carbon adsorbs dioxins, furans and heavy metals.
System control and monitoring
A proprietary control system ensures that both the operation of the plant and its environmental performance are optimised. Emissions are monitored continually and the data is collected and made available to the regulatory body. The system operates in automatic mode with minimal human intervention, freeing up personnel for tasks such as service and preventative maintenance. The control system also features a separate and independent automatic shutdown system.
Utilities (e.g. water and natural gas)
The ENERGOS plant is equipped with the following utilities:
- power distribution system
- emergency power generating unit
- process air system
- re-circulated flue-gas system
- compressed air system
- hydraulic system
- water cooling system
- oil cooling system.