Reducing emissions to protect our environment
Bag Filters & Sorbent Injection
The installation of Emission bag filter and sorbent injection neutralises pollutants in the gas stream, the bag filter is predominately filtering Dioxins and Furans, Sulphur Dioxide and total particular matter. We condition the gas stream to a perfect gas velocity downstream of the bag filter, this promotes perfect mixing of 2 separate lines of hydrated lime and activated carbon for chemical reactions to take place before entering the bag house.
The CTEC system controls the emissions during and after the advanced conversion chamber. Advanced conversion is controlled by Exhaust Gas Recirculation (EGR) providing a specific flame position control, using tertiary air fed in at the primary stage in order to cool the main grate frame, then at the end for final stage, through 2 perforated side plates located at the first half of the grate. This controls the; Gasification, Partial advanced conversion, total advanced conversion & Ash final conversion.
The tertiary air is also used as a partial start of burn of the VOC's and CO, just before the use of main secondary air ramps located at the start of main flue gas to cyclone. High temperature cyclone & cooling chamber changes the gas temperatures from 900°C down to 600°C, this temperature drop changes the state of sticky salt tars into ash which can then be recovered up to 85% in the cyclone.
High Temperature Cyclone & Cooling chamber
Exhaust gas recirculation enters upstream of the cooling chamber changing gas temperatures from 900°C down to 600°C. Temperature drop changes the state of sticky salt tars into ash which can then be recovered up to 85% in the cyclone.
The cyclone design follows a basic principle that the height of the unit is considerably greater than the unit diameter. This induces the swirling air or gases to follow a long spiral path, subjecting any particles to centrifugal separating forces for a maximum period of time. The gas inlets and outlets are proportioned and positioned in such a way as to present a smooth, uninterrupted flow without undue turbulence which would otherwise interfere with good dust separation.
NOx Control Summary
In order to control the NOX emissions according to EU regulations CTEC proposes the following solution, taking into account the special requirements for catalytic installation. The solution is to take the clean gas back stream from the polishing ( carbon trap) stage, at 170°C temperature in order to re-heat it up to 250°C through a special heat exchanger located between the cyclone and superheated exchanger.
Designed to remove dioxins that may pass through gas clean up bag filter. Requirement dependant on dioxins levels in waste.
With the addition of a water scrubber system this will further greatly reduce the emissions to virtually zero. Also particulate emissions of heavy metals are significantly reduced, further contributing to improvements in air quality. The separation is via water filtration membranes