WHAT IS GASIFICATION?
Gasification is a thermochemical process that takes place at high temperatures (around 1000 °C) in a low-oxygen environment, through which it is possible to transform a solid fuel into a synthetic fuel gas (syngas or bio-syngas in the case of biomass). The syngas produced is mostly a mixture of hydrogen (H2), methane (CH4), carbon monoxide (CO), carbon dioxide (CO2) and nitrogen (N): this unburned gas maintains the energy properties of the solid fuel from which it originates. The goal of gasification is to take control over the discrete thermal processes, usually mixed in combustion, and reorganize them: drying, pyrolysis, combustion, cracking and reduction. These processes are naturally present in the flame that we see in a fireplace where wood logs are burning, or the flame burning off a simple match, although they mix in such a way that the human eye cannot distinguish them. Through gasification we can isolate these processes and interrupt them before gas combustion happens, in order to pipe it away and burn elsewhere.
Gasification was originally introduced in the XIX century, when coal was gasified to produce town gas for public lightning and cooking stoves; gradually, natural gas and electricity distribution networks displaced it, but still gasification has been widely used from early XX century not only for making a combustible gas, but also in the production of synthetic chemicals such as ammonia, liquid fuels, tar, char, hydrogen… Wood gas and gasifiers were widely used in Europe also on vehicles during World War II, as gasoline and diesel were rationed or unavailable: in fact, the gasification of 3 kg of beechwood could replace the equivalent of 1 litre of gasoline. With the oil industry development and the spread of methane and its distribution networks, gasification systems have lost their importance, while remaining a standard technology on industrial plants powered by coal or waste.
RENEWABLE ENERGY AND GASIFICATION: BENEFITS
A gasification process using biomass as a fuel produces bio-syngas and therefore renewable energy. This energy is called “green” as it allows to avoid the increase in CO2 caused by the use of fossil sources (coal, oil and gas). Bioenergy is already one of the major sources of thermal energy in traditional uses of firewood and, more recently, pellets.
Thanks to RESET SyngaSmart technology it is possible to generate not only thermal energy but also electricity, through a single process and taking advantage of the energy contained in biomass. SyngaSmart plants are extremely safe because there is no on-board gas storage: the fuel is generated and immediately used, thus avoiding risks of fire, explosions or leaks.
With the use of biomass gasification plants, the dependence on fossil fuels is reduced and no new carbon dioxide is released into the atmosphere. SyngaSmart technology also allows to store in the biochar a part of the carbon dioxide originally absorbed by biomass (carbon sink), removing the excess from the natural CO2 cycle and offsetting the greenhouse gas emissions resulting from the combustion of fossil fuels. SyngaSmart is a carbon-negative technology.
BIOMASS GASIFICATION AND COGENERATION PLANTS OPERATION
Biomass is present in various forms: one of these is wood chips, a solid biofuel represented by chips of wood produced through standard machinery (chipper or shredder) from wood waste, prunings and forest residues. Wood is an abundant and often unused resource, occasionally disposed as waste, that shall be seriously taken into consideration for energy production, since it is renewable and widely available.
Woodchips can be used in specific gasification plants where this feedstock is transformed into bio-syngas, which can displace fossil gases such as methane or LPG for energy production.
When generating power by matching an internal combustion engine with an alternator, we have a simultaneous production of electricity and thermal energy that normally is not recovered: it is the case of cars, where the most of the fuel energy is lost and only a small part of it is transformed into mechanical energy that allows the car motion of the car. SyngaSmart technology is designed to recover thermal energy from both the engine coolant and exhaust fumes, thus minimizing losses and maximizing the availability of hot water.