Abstract
Biomass can be considered as a strategic resource because it is not only renewable, but also available everywhere. It can provide products of vital interest to sectors of strong external dependence (i.e. transportation fuel, electricity, chemicals etc.), and also may raise benefits for the environment and for socio-economic development, particularly in rural areas.
Fuels derived from biomass are renewable and are sufficiently similar to fossil fuels to provide direct replacement. The primary ways of converting biomass into biofuels/energy are combustion, gasification, liquefaction, and biochemical processes. Biochemical processes convert biomass to liquid fuel (bioethanol, biodiesel) through a fermentation process.
One of the most tempting energy crops is the sweet sorghum, which can be grown in different climatic conditions, has been identified as the first promising crop having the potential to provide a wide spectrum of energy and industrial commodities that can match local market situations.
Sweet sorghum produces a very high yield in terms of grains, sugar, lignocellulosic biomass (on average a total of 30 dry t/ha per year) in low-quality soils, with much lower inputs of fertilizers and irrigation water than other crops (200 t water/dry t of crop, representing half of the water amount required by sugar beet and a third of the requirement for sugar cane or corn). The total yield ofbioethanol can reach 5 m3/ha per year. Plantations need less seed than for other crops: 15 kg/ha compared with 40 kg/ha for corn or 150 kg/ha for wheat.
It is expected that bioethanol from sweet sorghum can be co-produced in the EU (central and south- east regions) at a marginal cost of about 250 USD/m3. The selling value of bioethanol produced in integrated complexes with sweet-sorghum plantations will depend on the market value of the other co-products (heat, electricity, etc.) and possible support from investments that are sometimes available (e.g. structural funds, etc.) to create permanent jobs.
The paper presents a study of the technical and economic feasibility of an integrated plant using sweet sorghum as feedstock in Romania.
The integrated concept aims at producing bioethanol from sweet sorghum crops, green biomass (sweet sorghum), carbon dioxide, fertilizers, and power (heat and electricity), by combining agricultural activities, with biochemical and power generation activities.
