Labs and Facilities for biomass

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1 BIOMASS TECHNOLOGY 1 Italian Agency for new Technologies,Energy, RESEARCH CENTER OF TRISAIA In Italy, the recent acknowledgement of the European directive 30/2003/CE about the mandatory blending of biofuels to the fossil fuels for transportation has stimulated various industrial investments in this sector. Nevertheless, the framework of the Italian agriculture does not give wide-ranging perspectives for the development of a bioethanol industry only based on dedicated crops. A reliable production of biofuels in Italy needs to lean on both dedicated crops and lignocellulosic residues. Since several years, ENEA works on bioethanol production from lignocellulosic biomass through steam explosion pretreatment and enzymatic hydrolysis. Labs and Facilities for biomass

2 BIOMASS TECHNOLOGY 2 Italian Agency for new Technologies,Energy, STEAM EXPLOSION PROCESS The Steam Explosion process is based upon the use of high pressure and temperature saturated steam: the operating pressure ranges from 15 to 30 kg/cm 2 and the corresponding temperature ranges between 180 and 230 C. The comparatively high temperature determines the breaking of the chemical bonds between lignin, cellulose and hemicellulose. After the steam treatment is completed, the biomass is discharged through a narrow orifice; at this stage, intercellular liquids evaporate instantaneously, thus bringing an extensive destructuring. The effects of chemical hydrolysis and mechanical stress on lignocellulosic material are determined by the process severity parameters. The severity parameter indicate as Ro is quantified by a semi empirical relation that is a function of retention time and saturated steam temperature, as shown below: R 0 = t * exp[(t-100)/14.75] Where: T is temperature in C t is the time in minutes. Generally speaking, materials exploded in hot water and in alkaline solutions are more soluble than they were in their original state. This property is exploited in order to separate lignin, hemicellulose and cellulose using aqueous extractions, that can be easily used as secondary raw materials. In fact: Lignin is a complex phenylpropane polymer and is thus an aromatic which can be used to produce asphalt, carbon fibers, vanillin, etc. Hemicellulose is a polymer consisting of sugars with 5 or 6 carbon atoms. It is used to produce non cariogenic sweeteners (xylithol) or solvents. Cellulose is a glucose polymer. It is used to manufacture paper and textile fibers, or as a fermentation substrate for alcohol production. The figure 1 shows the scheme of steam explosion process. fig 1. Steam explosion process scheme.

3 BIOMASS TECHNOLOGY 3 Italian Agency for new Technologies,Energy, The Batch Plant This non-continuous plant is used to make feasibility studies and initial screening on the vegetable to be treated in order to determine the optimum operational conditions. The plant is an independent unit, especially suitable for research activities. It is completely encased in a steel framework allowing easy access to the various components, as well as providing a protective screen for personnel. The reactor is a pressure vessel made of stainless steel having a capacity of 10 liters and can contain 1 kg of biomass per cycle. The reactor chamber is surrounded by a steam jacket so that, when it is working, the internal and external temperature are the same and the vapor condensation is minimized. Biomass is introduced in the reactor through a pneumatic loading valve and then soaked with saturated steam. After the elapsed time, the blow valve is opened, pressure decreases dramatically in a very short time and the cotton stalk is discharged in a storage tank (150 liters volume). A water condenser is connected with the storage tank in order to recover and remove as a liquid waste the volatile organic compounds produced during the process. The necessary saturated steam used during the process is supplied by an external 16 kw boiler. The figure 2 shows a scheme of SE batch plant, while the figure 3 shows a photo of the batch plant present at CR ENEA Trisaia. fig 2. Scheme of steam explosion batch plant

4 BIOMASS TECHNOLOGY 4 Italian Agency for new Technologies,Energy, fig 3. steam explosion batch plant at ENEA Center.

5 BIOMASS TECHNOLOGY 5 Italian Agency for new Technologies,Energy, The Steam Explosion continuous Plant Stele is a pilot station where continuous processing is carried out on a significant scale. It is possible to process up to 300 kg/h of vegetal matter and obtain three separated products: lignin, hemicellulose and cellulose. A waste treatment section completes the process. The biomass is stored inside a trench; it is reduced to the suitable size (2x1x0.2 cm) by a straw chopper and then transported to a storage bin by a pneumatic conveyor. In this stage, a suitable device (cyclone) prevents the release of any dust into the atmosphere. The biomass chips are conveyed from the tank by means of a screw device and conveyor belts, automatically weighed and humidified up to 50%. Finally, the biomass is conveyed to a feeder, where it is compressed into a dense plug, forming a cap which seals the reactor. The reactor (fig 4) is tubular, 30 cm. in diameter and 3 m high. It is made of steel and is designed to resist pressure up to 30 kg/cm. It has external insulation and internal probes to monitor temperature and pressure levels. A 200 kw boiler provides high pressure saturated steam for hydrothermal treatment. A system of internal screws determines the movement of the biomass and the time of treatment. Release at atmospheric pressure (explosion) is controlled by an expansion valve which opens at regular intervals and for a preset length of time. Figure 5 displays the overall plant scheme. The exploded biomass, mixed with steam expelled by the reactor, is conveyed to an 8 m 3 expansion tank where separation takes place. The steam containing the organic components derived from the decomposition of lignin and pentosans is condensed in a scrubber through cold water splashes. The solid part can be either used as animal feed and raw material for the production of panels, or reprocessed in the extraction area of the plant. The extraction of hemicellulose is carried out with C water inside a 3 m 3 extractor; the suspension (5-10% solid) is then filtered with a counter current multistage belt filter 1 m large and 2.5 m long. The filtrate is concentrated to a syrup-like liquid (50% water) in a falling film evaporator. Lignin extraction from the residual solid part of the first belt filter is carried out by similar equipments, with a temperature of approximately 90 C and with a sodium hydroxide alkaline solution. The remaining part of the hemicellulose and lignin extraction is enriched in the cellulose fraction, which is neutralized and, possibly, dried. The liquid waste from scrubber and belt filters are processed in 2 m 3 /h plant. The solid and syruplike waste is burned in a diesel- powered rotating drum incinerator. In principle, any lignocellulosic material can undergo steam explosion process: algae, wood, annual plants, urban solid waste and recycling paper. The availability of semi-industrial equipment in the technology hall of the Stele plant also enables researchers to undertake various types of processing on a significant scale, such as the bleaching of cellulose paste. Preliminary testing is carried out by means of the Batch Reactor for every kind of biomass or for a different use of the same biomass, so as to establish the following elements: macro elements separation degree, carbohydrate decomposition, yields, product quality and environmental impact. If the results are good from both the technological and economic point of view, the process is repeated in the main plant. If the Steam Explosion plant is used in paper production, the biomass has to undergo a relatively mild processing to free the cellulose fibers without dramatic polymerization reduction. Heavier treatment leads to greater solubility of hemicellulose and lignin. This obviously increases decomposition phenomena such as the lignin browning and furfural production. The Steam Explosion experimental station is equipped with a laboratory for analyses of the lignocellulosic input products and of the output waste materials. Advanced techniques are used such as gas chromatography, high pressure ionic chromatography, FTIR and UV spectroscopy, atomic absorption, calorimetry, thermal analysis, etc.

6 BIOMASS TECHNOLOGY 6 Italian Agency for new Technologies,Energy, The laboratory is also equipped for research on chemical and physical changes induced in lignocellulosic materials by thermal processing (pyrolysis, gasification, combustion). The most commonly performed types of chemical analysis include the testing of carbohydrates (sugars and polysaccharides), lignin and inorganic components in vegetables. The total amounts of organic material, suspended solids and volatile organic compounds in the waste material are also analyzed. fig 4. scheme of continuous steam reactor. fig 5. scheme of STELE plant.

7 BIOMASS TECHNOLOGY 7 Italian Agency for new Technologies,Energy, Figure 6 is a photo of the steam explosion plant. fig 6. steam explosion continuous plant (STELE) at ENEA Center.

8 BIOMASS TECHNOLOGY 8 Italian Agency for new Technologies,Energy, BIOTECHNOLOGICAL LABORATORIES Figure 7-8display some bioreactors used for the production of bioethanol and some labs equipments used for the chemical characterization 1.5 L 10 L 50 L Fig7: Photos of the biotechnological labs

9 BIOMASS TECHNOLOGY 9 Italian Agency for new Technologies,Energy, GC-MS & TDS/DIP ICP-OES ICP-MS HPIC-PED HPIC-RI HPLC-UV UV-Vis FTIR AAS Fig. 8 Photos of the instrumental equipments for the chemical characterizations The labs are equipped for complete characterizations of the raw materials used and of the process streams. More in details the following analysis can be carried out: Proximate & Ultimate Analysis Thermogravimetric Analysis (TGA) Spectrophotometry (FTIR, UV-Vis, AAS, ICP-OES) and spectrometry (ICP-MS) Liquid and gaseous, process streams characterisation ( HPLC, HPIC, GC-TCD, GC-MS) Sample preparation Sampling on-site & on-line In the following, a list of routine procedures for steams sampling and analysis is given: CEN, ISO, ASTM & DIN for raw material characterisation CEN/TS 15439: Biomass gasification - Tar and particles in product gases Sampling and analysis