Meva’s technology is a biomass gasification system of entrained flow gasifier type. The gasification reactions take place in a dense cloud of biomass particles that is blown into the preheated gasification reactor where it forms a vortex (whirl) spinning down the reactor and allowing the particles to be gasified to syngas.
Meanwhile the resulting ash is separated from the syngas due to the centrifugal forces of the cyclone. When reaching the bottom walls the almost particle free syngas changes direction and flows back up where it exits in a centrally located pipe. The separated ash is however forced down towards the bottom where it is collected. Contrasting to most gasifiers of entrained flow type, the Meva technology is fed with air and not oxygen, thereby constituting a far less expensive solution. Meva Energy has filed several patent applications covering key functionality of the technology.
The Meva process
Meva Energy´s technology is a complete system from gasifier to syngas cleaning for production of renewable fuel gas which is fed to a power engine genset for distributed production of power and heat. Alternatively the resulting renewable gas can be used to replace fossil gases such as natural gas or propane in e.g. an industrial drying process.
The system is designed as a closed loop leaving no residues other than ash. Also, the entire system is fully automized and is designed to be remotely and continuously operated.
The most important feature of the technology is its ability to produce true high quality gas. It all started with the fundamental engineering insight that in order to achieve a defined result you need to define the starting point.
For the Meva technology that is manifested by specifying the feedstock particle size to a maximum of 1 mm. If it is larger, it needs to be grinded. But the output of that extra effort is just great, the system produces gas with extraordinarily even quality. This is due to the inherent continuous character of cyclone gasification of small fraction feedstocks and the avoidance all sorts of batch-like injecting and ejecting resulting in sudden changes of process conditions. Thanks to this, we are able to use our syngas with highly effective lean burn combustion engines – a unique ability within the gasification industry.
Maximising power output
High efficiency due to lean burn combustion
Maximized fuel efficiency in fixed installations of combustion engines is generally achieved by applying the concept of lean burn. Due to this principle, the engine can use a higher compression ratio and thus a higher level of efficiency and more efficient fuel use. However, lean burn engines demand stable fuel supply conditions and they cannot tolerate a quickly changed heating value or flow rate.
To the knowledge of Meva Energy, Meva’s technology is the only gasification system in the world being able to use lean burn CHP engines. The reason is simple; the incomparably continuos and stable character of the process ensures that the gas supply exhibits extremely small level of variation.
Engine installation at Hortlax. The Hortlax plant is located in Piteå, Sweden.
Brochure: Cummins about Hortlax plant (PDF)