Filtration and Monitoring Systems

The ceramic filter consists of a series of pollution control systems for specifically dealing with the off gas from an incinerator. Typically installed on a high capacity incinerator plant, this pollution control system will capture all the gases, soot, and entrained solids emitted to meet the European regulations which are set out in directive 2000/76/EC. Such a filtration system typically has a high removal rate of 97% for particulates.

This dry filtration system operates by passing the exhaust gasses through a series of chambers and processes, these are:

Heat Exchanger
A heat exchanger cools down gasses to between 400°C-420°C. This rapid temperature collapse from 1100°C helps reduce dioxin and furan reformation. It also sets up the flue gas stream for the optimum temperature for the (following) acid scrubber function.

Acid Scrubber
Lime is fed into the system via a hopper. This material is then steadily injected into the gas stream to neutralise the acidic gasses such as HCL, HF, and SO2. Spent lime is then removed by the final stage of the gas scrubbing process that is the particulates filtration system.

Ceramic Filtration System
Gas is pulled through vacuum-formed ceramic filter tubes. These filters remove the heavy particulates and used lime in an extremely efficient manner. The gas is drawn through the system with a draught fan and the resulting clean and safe gases are vented to atmosphere.

Cleaning System
Once the cycle is complete, an automatic cleaning cycle can be initiated. This cycle reverse pulses compressed air through the ceramic filters, dislodging trapped particulates to clean them. Once complete, the resulting material can be removed via the inspection hatch.

The Addfield Wet Scrubber system is primarily designed as particle suppressant system, ideally suited to high capacity incineration machines. Heavy particulates are removed from the exhaust gas using water injected from the roof of the scrubber system.

This bolt on system can be added to any incineration machine in the Addfield range and is scaled according to the specific application. Constructed from a stainless steel, the vessel encapsulates multiple water spraying nozzles.

The primary function in which the wet scrubbers operate is to cause dust particles to attach to the water droplets. This contact occurs in three phases, these are:

Inertial Impact
The direct impact of a particle with a water droplet, thus removing it from the emission gas stream. When the velocity between the two objects is relative this typically occurs.

Interception
If a faster particle is not large enough to impact as water droplets, this gas particle may attempt to go around a slower or stationary object. As it does, its inertial energy will slow subsequently it is likely to impact a following water droplet in a scrubber system thus removing it from a the emission gas stream.

Diffusion
Occurring in particles typically less than 0.3 micron, this process provides higher collection than would otherwise be expected due to the mixture of inertial impaction and Interception.

Acid Gas Removal
Calcium carbonate can also be added to water, with the resulting slurry sprayed into a flue gas scrubber. The process is found to be more efficient if a calcium hydroxide/water slurry is used, removing over 95% of Sulphur dioxide. The Sulphur dioxide is absorbed into the spray and precipitates as wet calcium sulphate. By re-circulating the slurry and injecting oxygen, calcium sulphate (gypsum) is formed which can be sold as a by-product. CaSO3 0.5H2O + 0.5O2 + 1.5H2O -> CaSO4 . 2H2O