Howden incinerators are designed for the thermal destruction of a number of different waste streams, such as general waste, medical and hazardous waste, veterinary waste including animal carcasses, liquid waste, and gaseous waste.
The Howden incineration plant generally consists of the following components:
Primary chamber; wherein solid waste is loaded and sterile ash is removed from.
Secondary chamber/thermal oxidiser; wherein the complete oxidisation of the gas takes place, and the high temperature destruction of VOC’s takes place thereby eliminating foul odours and smoke.
Flue gas cooler; whereby the flue gas is suddenly cooled below the temperature (<200°C) where the formation of dioxins is favoured. It is possible to recover the waste heat from the flue gas cooler in order to make the process more thermally efficient. The waste heat can be used within the plant, or for any other desired application.
Flue gas conditioning; whereby the injection of an adsorbent removes environmentally harmful pollutants such as heavy metals, HCl and SO2.
Flue gas filtration; whereby the environmentally harmful particulate suspended in the flue gas is captured by passing the flue gas through a fabric filter.
Stack; whereby the cleaned and conditioned flue gas is emitted into the atmosphere at the correct temperature and velocity.
Depending on the waste to be processed, the final incinerator design will consist of a combination of some or all of the above mentioned pieces of equipment.
The flue gasses are extracted with the aid of an induced draught fan usually located between the fabric filter and stack. The heat source required for the primary and secondary chambers is supplied by burners that are typically fired on LPG to limit the amount of Sulphur introduced into the system; all burner systems are designed in compliance with the SANS 329 specification to insure the safety of the equipment and operators.
The primary and secondary chambers are well insulated to limit the amount of heat losses, thereby increasing the thermal efficiency of the process.
Varying degrees of automation exist, and the level of automation required is largely driven by the quantity of waste required to be processed. We can offer batch type operations where the waste is manually loaded into the chamber, and after burn down is complete, the sterile ash is manually removed. Continuous operations will include a combination automatic ram loader and de-ashing ram, hydraulically powered and used to both load the waste into the primary chamber and remove the ash from the primary chamber. The ash will typically be collected in a forklift bin and can be emptied into a larger skip bin as required.
The emissions from the stack of an incineration facility must be within certain limits and conditions in order to comply with most modern legislation. Continuous stack monitoring equipment located at the end of the process is used to measure and record the emissions in order to provide proof to the authorities that your plant is operating within the legal framework.