Biofuels Versus Fossil Fuels Use of biofuels over fossil fuels seems to be advantageous based on the effects influenced by the environment are taken into consideration. If more priority is given to the preservation of resources from greenhouse gases and fossil fuels, all biofuels favorably play an active role when compared with fossil fuels. Impacts brought out by environmental events like acidification, eutrophication, or ozone depletion result in the opposite effect. These disadvantages are connected to aggressive agricultural productions resulting in the emission of nitrogen compounds, which creates terrible impacts on the environment.
The advantages of biofuels vary with one another based on the analysis. Apart from the known sources utilized for biofuel production, accumulated local areas could be used in biofuel production as it has a high heat of combustion.
Between Fossil fuel and biomass fuel as coal to pellet both the lower bulk density (200–800 kg m− 3) and the lower calorific value (typically 15–20 MJ kg− one on a dry basis) compared to coal means that the volume to store as well as required transport capacity for biomass is significantly larger per gigajoule. One method to increase the bulk density is pelleting or briquetting, which also improves the bulk handling properties of the fuel, and the drier pellet/briquette will have a higher calorific value, thus reducing the costs for transport, but it is also more expensive to make
The ash content of many biomasses is lower than that of coal: < 5%, with the ash content of clean stem wood often well below 0.5%. There are also biomass types with very high ash content like rice husks that can have more than 15% ash. The composition of the ash in most biomass is more troublesome than coal ash from a slagging/fouling/bed agglomeration point of view with a high content of alkali like calcium (Ca) and potassium (K). Calcium- and potassium-containing ash deposits very quickly on surfaces forming fouling in the form of CaO, CaSO4, and K2SO4. These deposits harden on superheaters if not removed frequently by soot blowing. Some biomass fuels can have high chlorine concentrations, which increases the risk of fouling and particularly high-temperature corrosion in the superheaters. Still, most of them contain significantly less sulfur than the average coal.
The format of delivery for biomass fuels is different from coal as well and requires mixed reception and handling systems. The fuel handling system on a power station has to be designed for particular types of fuel as the handling characteristics vary widely. Take straw and coconut shell as two extreme examples: it is easy to see that the requirements and volumetric capacity for a plant delivering the same power output would be entirely different for these two fuels.
The chemical characteristics of the fuel in question have a substantial impact on combustion (carbon burnout, slagging, fouling) and environmental (NOx, SOx, dust) performance as well as fly ash saleability, load capability, and overall plant efficiency. Some of the critical factors here are calorific value, moisture, ash content, ash composition, trace element content, and ash fusion temperature.
The most critical domestic biomass fuel in the current wood. It comes in many forms like hardwood from the forest, recycled wood. That wood is usually delivered as sawdust, wood chips, or pellets. Dry basis has a calorific value in the order of 4300- 4500 cal kg− one and typically well below 2% ash. The moisture content varies, with wood pellets usually containing < 8% and recently felled wood up to 50%.
