Energy uses of plants : reasons and scenarios
Never before has a use as old as that of plants , which begins in prehistoric times with the discovery of fire , it has become so modern . A world with a population still growing at a rapid pace , according to UN projections at least until 2050 , not only in need of food, but also energy , and agricultural plants will have to make their contribution to meet both needs .
The main motivation of the need for the plants to produce energy is the renewable nature of the energy that it yields . The concept of renewability is one of the pillars of ecology, and indicates the possibility of producing each year a good or a process without affecting the reserves of the planet, thus entering into a logic loop production systems for energy and consumer goods .
The great advantage of the use of energy plants is that , for each process of energy production that requires a combustion , their contribution , as well as renewable , is also carbon neutral .
Other renewable sources such as wind , for example for the production of electricity , does not require combustion of carbon . The concept of carbon neutrality concerns , in fact , the impact on the rise in global greenhouse gas carbon dioxide ( CO2), which in turn could have an impact on the increase in average temperature of the atmosphere, known as global warming or global warming .
The plants do nothing but return to the atmosphere, as a result of combustion , the CO2 taken from them at the same atmosphere through photosynthesis and stored in the biosphere.
Biofuels are defined as all those derived from biomass obtained while using different methods for this are considered in the context of renewable energy.
The main biofuels are:
biodiesel to be used in place of diesel fuel , made from oilseeds for crushing or extraction followed by solvent extraction and , in general, by a process of purification industries ( esterification ) .
Bio-ethanol as a substitute for gasoline , produced by fermentation of biomass rich in starch or sugar , natural gas and heat produced by the anaerobic fermentation of biomass plants and animals.
Currently the locations of the sources of renewable energy are three:
- Production of electricity;
- Production of thermal energy for heating ;
- Production of biofuels for transport .
Energy uses of potato
The destinations of the potato are two main energy : conversion into bioethanol and transformation into biogas. The two transformations , both biochemical and employees of micro-organisms , performed in a matrix suitable for fermentation .
To produce bioethanol , potato starch is hydrolyzed by enzymes and is then fermented by yeast into ethanol.
The production of biogas occurs , instead , in the environment by anaerobic methane bacteria . The process is carried out starting from different mixtures based biomass , generally consisting of manure and vegetable masses , which can contain both whole potatoes is waste from industrial processing of the tuber .
Use of scraps
The chain of cold storage and distribution of the potato, as well as the potato processing industry , with the target food or non -food waste produces a type of relatively large :
- Tuber entire unsold ;
- Whole tuber size does not fit ;
- Tubers broken and failures;
- Skins (PPP Potato Peel Pulp) ;
- Pulp exhausted (PP, Potato Pulp) ;
- Water and liquid wastes (PFW , Potato Fruit Water) ;
- Other wastes (for example by the chips)
The amount of waste, if you add up the different types, may constitute a substantial part of the production. The destination of this waste is either that of as waste treatment , composting or energy use.
Scraps of potatoes and biogas production
The tubers discarded during the manufacturing process for the product presentation on the horticultural market are represented by two fractions:
- deteriorated in the course of collection;
- below or sopracalibro.
Other waste potatoes are produced in the course of industrial processing for the preparation of frozen or ready to fry
Additional waste from the food preparations you can have " expired "
At the Laboratory for the study of the biomass of the Department of Plant Production , University of Milan numerous analyzes were performed . The highest yield , as expected, it has with potato chips and this because in addition to starch is also present a residual oil , as the rest , although to a lesser extent , in the sample of frozen potatoes ready for frying .
The global importance of the increased production of energy from biomass to replace fossil fuels , the exploitation of energy waste is a goal to strive definitely in the potato , and not only in that culture , because , beyond the energy benefits , it is not going to affect land areas in pataticoltura . For energy uses should be considered in both the ethanol fermentation is the conversion to biogas.
The destination of the potato and its waste to ethanol production is not a new industrial process , since by the time the potato is known in North Europe as one of the most used raw materials for the production of ethyl alcohol on an industrial scale . As in the case of other starches and cellulosic biomass , to produce bioethanol potato starch is first hydrolysed by enzymes , in a stage of the process known as saccharification and then fermented by yeasts Saccharomyces cerevisiae yeast) in ethanol .
A fermentation has ended is the phase separation of the ethanol from the water for double distillation . Bioethanol can then be used as fuel as it is or mixed with gasoline from 15 to 85% . It can also be transformed into ETBE ( ethyl tertiary butyl ether ) , used as an anti-knock of origin for renewable gasoline engines , replacing such a function for the MTBE (methyl tertiary butyl ether ), obtained from coal . The theoretical yield into bioethanol , dependent on the starch content , is 7-8 g of ethyl alcohol per 100 g of potatoes.