EMPYRIO Compact mono-Incinerator

 

EMPYRIO inventors realized known principle of Fluidized Bed Combustion (FBC) in compact scale equipment to be able utilize small organic waste volumes. As a result, a set of unique equipment was developed, produced and succesfully tested. There are two main elements of the system: incinerator and dryer, which in tandem provides high-humidity sewage sludge drying and incineration without need of additional energy resources (gas, oil, etc), and without adding other raw materials (sawdust, woodchips, etc.) to increase the energy intensity of incinerated waste.

 

Simplified operation principle is the following: hot flue gases from the incinerator enter the dryer. There also comes wet organic waste. When they contact, occurs drying of waste for further burning in incinerator. Another words, thermal energy of waste incineration is used for drying next party of wet waste. Thus process is cyclic and does not require adding to the process additional energy or material sources except for initial startup.

 

One unit has variable capacities of 1-5 tons of dry solid (DS) per day (400-2000 DS t/year). Productivity can be more if several incinerators will work in parallel and scalability of equipment is also possible. Incinerator can fit in one container or even designed as portable.

 

INCINERATION PROCESS DESCRIPTION

 

Incineration of sewage sludge is based on the following principle. Fuel (gas, oil) is fed to the incinerator (1) for the initial start-up of the process of combustion. Hot flue gases from the incinerator pass through the afterburner (2) and fed to the dryer (3). There also is fed wet sludge (4). When they contact occurs drying of sludge. From the dryer, the mixture of flue gases, water vapor and dry sludge enters an outer cyclone (5), where dry sludge is separated from the flue gases and water vapor. Dry sludge (6) from the cyclone is fed to the incinerator and the gases are purified. From this moment the process becomes cyclical.

The combustion of the dried sewage sludge is conducted in a rotating fluidized bed incinerator (furnace) (1). The furnace consists of conical and cylindrical parts. There are several inlets of combustion air in the furnace, located at several levels and at different angles, mainly tangential. The first inlet is close to the bottom, but the last one – at the end of conical part. The dried sludge is fed to the incinerator with the combustion airflow. An internal cyclone (7) is located in the centre of the incinerator. The upper end of the cyclone located in a manner that the uprising rotating flow of combustion gases and ash passes it, and the ash is separated and transported down the cyclone. The lower part of the cyclone goes through the
bottom of the incinerator and ends with a gate to convey the separated ash to an ash container where it is collected for the further treatment. After passing of the upper part of the cyclone, the combustion gas flow is led through a short pipeline to the afterburning chamber (2) ensuring the retention time of the burning media at 850°C for at least 2 seconds.

When the afterburning is completed the hot flow of combustion gasses enters the next short pipeline to be fed to the sludge dryer (3). Wet sludge with a dry solids content around 25% is transported into dryer by a screw transporter or positive displacement pump. A mechanical macerator disintegrates the sludge mass to provide a large contact surface between the hot gasses and the sludge particles. As the sludge drying is provided by direct contact with the hot gasses, the composition and parameters of the flow media are changed substantially. The water vapour from the drying as well as the light particles of the dried sludge are added to the flow, but the average temperature decreases to 200°C. Thus, the main part of the energy yielded in combustion process is transferred to the wet sludge for drying. The process is energy-neutral, no additional fuel is required any more.

After the dryer, the flow media enters the next cyclone (5) where the dried sludge is separated and transported to the container to be ready for injection into combustion airflow and for burning. A portion of wet sludge mass (8) could be added at this stage to control the heat balance in the incinerator in order not to exceed the temperature high limits to avoid formation of nitrogen oxides. The combustion gasses (9) are treated to meet the legislation exhaust standards. Heat recovery is also included in this process. The recovered low-grade heat can be used for preheating of the wet sludge mass.