Thermal waste disposal processes have become more important than ever.
The handling of hazardous substances has held a mirror up to our eyes, especially in times of pandemics.
The first plants with closed firing systems and grates were developed for waste incineration around 150 years ago.
The first waste incinerator was in the Paddington district of London in 1870.
Since then the combustion technology has been further developed.
In the field of grate furnaces there were several developments which are still in use today, as well as rotary kilns and fluidised bed furnaces.
Grate firing systems are used in almost all cases for the incineration of municipal waste and most hazardous materials, including for example hospital waste.
Already since 1 June 2005, untreated municipal waste may no longer be landfilled in Germany and in other the EU countries.
As there was insufficient capacity at waste incineration plants at that time, the high-calorific fractions were used as substitute or secondary fuels in industrial plants, such as cement factories and power stations.
In addition, organic and inorganic pollutants were destroyed and eliminated.
The ZANNI combustion grate
An extension of time can be reached with a minimum of effort.
The air swirl with a huge amount into the combustible materials and convey them along the grate.
The swirling combustion air turns over the combustible materials, cracks it up and assist the whole combustion process.
Therfore also a high throughput rate is achieved per unit area of grate.
The system allows the user to be flexible in the choice of load cases.
Either mass throughput or residence time can be selected, depending on the application and, above all, on demand.
That is a giant step in the combustion technology.
The grate can be described as
Multi-medium combustion grate,
suitable for solids and sludge, such as sewage sludge,
simple but clever,
rigid and strong,
no moving parts,
dynamic and efficient,
high throughput rates,
advantageous investment costs,
advantageous operating costs,
advantageous maintenance costs,
designed as a wear part for easy replacement.
A large potential is contrasted with a small investment!
Conversion or retrofitting of old plants
Especially in existing combustion plants, which have operation problems, an enormous advantage in operation conditions and environmental protection can be achieved with minimum effort for conversion or retrofitting.
Incineration in waste or coal-fired power plants is required as a sewage sludge disposal method.
In many places there are licensing problems for new incineration plants.
Incineration ashes still have to be disposed of and stored.
The ashes of sewage sludge contain a high proportion of phosphorus, which can be recycled and reused in industry.
In addition, the thermal process can also be used to generate energy.
On this simple but clever combustion grate, the sewage sludge can be burned out to a maximum at high temperatures.
The grate area is very big and the supply with combustion air inside the combustible materials is optimal.
The combustion air cools the grate, absorbs the energy and dries the sludge even faster on the first stages by preheating.
This also protects the grate.
But if necessary the hot air generated before the filter due to our Air/Air cooler can be used also as pre-heated combustion and circulation air.
In this way a heat cycle could be created.
This could also be support the combustion and reduce costs.
But this could only be a case by case decision.
The amount of sewage sludge is minimised to a maximum by combustion.
Phosphorus, as a valuable component of the sewage sludge, can be recovered from the remaining ash in a later recycling process.
This grate technology enables sustainable waste management through independent thermal utilisation of the sewage sludge and the recovery of residual substances from the ashes.
The incineration can be decentralised on site in close proximity to the producer of the sewage sludge, thus eliminating transport costs and associated emissions.
This is also an additional contribution to environmental protection.
The ZANNI combustion grate is flexible in design and can be adapted to the given boundary conditions.
It is therefore also very suitable for retrofitting existing plants.
Of course, sufficient ventilation of the grate surfaces must be ensured and if necessary appropriate adjustments of the ventilation system, like fans and pipes, should be made.
As a generally advatage we could figure out that the combustion can be excellently controlled by combustion air at the right places.
The steps of the grate are equipped with air openings like nozzles.
The picture shows a ventilated grate surfaces on a support frame for sewage sludge.
Via the combustion air fans the fuel is swirled by air pulses and enriched with sufficient oxygen from the combustion air supplied.
This results in maximum burnout of the sewage sludge.
The utilisation is carried out on the combustion grate according to a classical principle
ignition and burnout.
The capacity of the grate is not significantly influenced by the mass, but by the consistency of the sludge.
Working principle and advantages on a view
The sewage sludge is fed to the combustion grate through an opening on ceiling or via a front filling system depending on the local requirements.
On the first stages of the combustion grate system the sewage sludges fed will be dried.
Depending on consistency, the local requirements, the constructional condition and so on, it is also possible to built a system of multi-stage grate on various levels. It is a flexible solution.
After the drying area the dried sludge will be slowly transported further by the combustion air ventilation of the grate as well by air impulses, pyrolysed and ignited on the subsequent stages before it be burnt out at a maximum on the rear stages.
The residence time of the sewage sludge can thus be also increased and a maximum energy yield achieved.
In many cases, the combustion grate system can be adapted to the structural conditions of old plants and makes these plants a valuable investment again.
In many cases, modifications, also due to the circumstances mentioned on the previous pages, are a sensible measure and good for the environment.
In classic grate systems or other mechanical blade solutions, there are mechanically moving components in the combustion chamber which are damaged in a relatively short time and wear thermally and mechanically.
Maintenance is therefore necessary at relatively short intervals and is usually also very expensive, as entire systems usually have to be replaced.
With the ZANNI combustion grate all mechanical parts are located outside the combustion chamber.
Thus, there is only wear material in the combustion chamber, i.e. the grate surface.
The simple construction of the system leads to comparatively low investment and follow-up costs, as well as low installation and maintenance times.
The availability of the system is thus also increased, which also improves the economic efficiency of a plant.
The ZANNI combustion grate is a sustainable innovation for an environmental friendly incineration.
Example of a general layout for sewage sludge
Summary of example combustion plants
All information and sizes of plants are available as PDF download on our download page!
Technical data in detail
As an example for the:
SLUDGE AND SOLID INCINERATION
Overview of all SICF-S plants (200 - 1000 kg/h)
- SICF 200-S (200 kg/h)
- SICF 300-S (300 kg/h)
- SICF 400-S (400 kg/h)
- SICF 500-S (500 kg/h)
- SICF 600-S (600 kg/h)
- SICF 800-S (800 kg/h)
- SICF 1000-S (1000 kg/h)
SICF plants (400 - 2000 kg/h)
- SICF 400 (400 kg/h)
- SICF 600 (600 kg/h)
- SICF 800 (800 kg/h)
- SICF 1000 (1000 kg/h)
- SICF 1200 (1200 kg/h)
- SICF 1600 (1600 kg/h)
- SICF 2000 (2000 kg/h)
Subject to change.
However, these are to be planned individually, if necessary also locally available and therefore not part of a general presentation.
Let's talk about it.
These flyers and brochures might also be of interest to you:
ZANNI combustion grate for all types of waste
ZANNI-Verbrennungsrost für alle Abfallarten
ZANNI combustion grate fact sheets
ZANNI Verbrennungsrost Fakten
ZANNI combustion grate for sewage sludge incineration
ZANNI Verbrennungsrost für Klärschlammverbrennung
Summary of the download links sewage sludge incineration grate
SOLUTIONS FOR THE SEWAGE SLUDGE INCINERATION
Zusammenfassung der Download Links Klärschlamm Verbrennungsrost
LÖSUNGEN FÜR DIE KLÄRSCHLAMMVERBRENNUNG