New invention by Sea Marconi for the conversion of carbonaceous matrices into biomaterials and bioenergy with “CO2 Negative – CO2N”

The last 2010 invention by Sea Marconi refers to a modular plant for the integrated conversion of carbonaceous matrices with the scope of obtaining and/or valorising derivative products, “energetic or bioenergetic vectors”, “energy or bioenergy” with low environmental impact or CO₂ neutral – CO₂ n or CO₂ negative – CO₂ N and/or “Zero emissions – ZE”.

This invention, for which Sea Marconi has applied for an international patent, is mainly based upon the plant configuration of multi-function reactors arranged in series or parallel among them, able to realise the required conversion processes. The idea by Sea Marconi is the result of an intense and continuous multi-discipline activity of research and development at Italian, European and international level.

This invention, for which Sea Marconi has applied for an international patent, is mainly based upon the plant configuration of multi-function reactors arranged in series or parallel among them, able to realise the required conversion processes. The idea by Sea Marconi is the result of an intense and continuous multi-discipline activity of research and development at Italian, European and international level.

Such approach has given positive results in terms of results such to develop into a new European project, Haloclean Application (n° G1RD-2002-03014) of which Sea Marconi was coordinator. These positive experiences at European level triggered a continuous enhancement process to finalise a modular and flexible plant in its applications solving what have been critical factors surfaced up to 2010.

Already in 2011 it is programmed the realisation of a technical scale and a mobile pilot scale plant to perform ad hoc on-site campaign at international level.

Within this invention and its field of application the following main terms are defined hereafter.

Critical factor I – “Explosion and/or fire” – his criticality is induced by the explosive atmosphere that can be triggered when presenting abnormal concentrations of oxygen and/or air in one or more sub-systems of the plant. In the pyrolysis and/or pyrogasification plants, this condition is typically determined by lack of sealing and/or inefficient compartmenting of the reaction ambients with respect to the external ambient. The triggering can be correlated to uncontrolled exothermal reactions, reversible or permanent seizing (i.e. screw – heating body – external fixed cylinder) of mechanical organs that present moving interfaces that could generate localised overheating at very high temperatures and/or deformation with wear and/or damaging of transmission shafts and/or revolving or fixed seals. This criticality potentially develops also during the periodic starting, cutting-off and emergency phases, since the plant goes through the lower (LEL) and upper (UEL) explosivity limits conditions. The limit concentration of oxygen depends upon the composition of the gas produced, humidity, temperature and pressure. For H₂and CO at ambient temperature and pressure, the limit concentration is 4%.

Critical factor II – “Irreversible seizing with blocking of the plant” – This criticality is characterised by the seizing between the transportation organ (i.e. screw) and the inner surface of the reactor/s when relative movements among contiguous parts are present. This criticality can trigger in case thermally conductive bodies made of hard materials are present. These bodies, for example if metal spheres are employed, could penetrate into the interspaces between contiguous moving organs.

Critical factor III – “Wear, friction corrosion” – his criticality is characterised by wears, scratching and/or reversible seizing, that in practical operations, can be correlated to the transportation of the material by the screw and cylinder of the fixed or rotating reactor, i.e. when relative motions between the two organs are present. They show the same effects indicated for Critical Factor II, but with a lower intensity. Irreversible corrosive phenomena of the metals can occur in presence of atmospheres rich in CO, CO₂and other gaseous compounds containing Carbon when operating in a range of temperatures from 350°C up to 800 °C. These phenomena, designated as “metal dusting” cause the pulverisation of steels to the point of determining the progressive deterioration of structural parts eventually causing their collapse.

Critical factor IV – “Thermal exchange inefficiency” – This criticality is characterised by eating inefficiencies due to low surfaces available for the transfer of heath between the heating parts and the matrices to be converted. Also, thermal inefficiency can be amplified by inefficient recoveries of energy inside the plant itself.

Critical factor V – “Insufficient revolving and/or static gas sealings” – In the patents listed here above, the extraction of air/oxygen potentially present in the pyrolysis reactor has been claimed, without providing precise technical indications on how the compartmenting of the reactor itself is occurring. Also, the type and the number of levels of compartmenting implemented by appropriate and reliable solutions capable of guaranteeing the absence of oxygen and the sealing of gases inside the reactor toward the external ambient are not mentioned

Critical factor VI – “Lack of mixing” – The thermal profile can result lacking or inhomogeneous for the lack of the energetic mixing action of the metal heating bodies with the carbonaceous matrix present in the reactor. In effect, for the technologies currently available at international level employing transportation organs (i.e. screws) with or without metallic heating bodies (i.e. metal spheres), under an operational point of view, the contribution given to the mixing of the material to be treated by the metal heating bodies by the movement of the screw results marginal. Consequently, for the abovementioned technologies the transportation function is predominant, with the material that, under the effect of gravity, remains resting on the bottom of the reactor for the entire duration of the reaction process.

Critical factor VII – “Lack of milling”– The thermo chemical conversion results lacking or inhomogeneous for the lack of the energetic milling action of the material to be treated capable of increasing the exchange surface and an intimate contact such to reduce the times, the homogeneity of conversion and the capability to promote reactions triggered by properly formulated additives. The importance of such requisite in terms of minimal particle dimensions is well-known at scientific level, but the technologies currently available worldwide do not address any “milling” function embedded in the process. The operation practice demonstrates that a rotary furnace and a simple screw do not provide the dynamic conditions required to reach such fragmentation. In fact, under the effect of gravity the material and the metal heating bodies remain resting on the bottom of the reactor.

Critical factor VIII – “Lack of catalytic effect“ – Within the technologies currently available at international level, the significant catalytic action that can be performed through the thermally conductive bodies themselves, employing specific metals or additives, results absent. The catalytic actions would make the conversion process more efficient and safe at a lower temperature, in shorter times and with an efficient conversion of undesired by-products.

Critical factor IX – “Lack of operational flexibility, compactness and modulability” – The technologies currently available at international level show not to address the flexibility in terms of feedstock that can be handled. It is well-known that in the typical pyrolysis and/or pyro gasification reactors process discontinuities are created by the lack of feeding that do not guarantee the conditions of homogeneity of the chemical-physical characteristics (i.e. humidity, granulometry etc.) of the carbonaceous matrices to be converted. To process heterogeneous carbonaceous matrices, the conversion processes must also provide the synergic combination of the operational parameters focalised toward a better valorisation of solid matrices (i.e. production of torrefacted, biochar etc.) liquid matrices (pyrolysis liquid) and gaseous matrices (syngas).

Critical factor X – “Lack or inefficient conversion and abatement of POPs and/or TARs, neutralisation of gases and/or minimisation of greenhouse effect – GWP” – Within the production of synthesis gases (syngas) one of the main critical factors for the applications is represented by the formation of TARs (by-product of the pyrogasification processes including a large spectrum of organic compounds, generally constituted by several aromatic rings – PCA etc.). The physical chemical characteristics of viscous and insoluble TARs clogging the ducts represent a true “Achilles tendon” in these plants and cogeneration systems (i.e. gas engines, turbines etc.). Another typical critical compound present in syngas produced by biomasses, besides NO_xs, is ammonia NH₃