Gastifikasi biomass Boiler
Definition of Biomass
Biomass is a renewable energy source that refers to biological materials derived from organisms that have recently died (compared to fossil fuels). The most common sources of biomass are wood fuel, waste and alcohol. Biomass is a renewable energy source because plants can grow back on the same land. Wood is currently the most widely used source of biomass. In the United States, for example, almost 90% of biomass comes from wood as fuel. Biomass is considered carbon neutral, this means that biomass takes carbon from the atmosphere when plants grow, and returns it to the air when it is burned. That is why, at least according to the theory, there is a closed carbon cycle without increasing levels of carbon dioxide (CO2) in the atmosphere. A form of energy obtained directly from living things (plants). Examples: wood, agricultural waste, alcohol, garbage etc.
Biomass sources
Firewood, twigs, and agricultural or plantation waste, even household, municipal and industrial waste is a huge potential as a biomass energy source in Indonesia. These energy sources have the potential for electricity generation, both through direct energy conversion processes and between energy conversion.
Biomass is organic material that is produced through photosynthesis so that biomass also has a designation given for material left over from plants or animals such as wood from forests, agricultural waste material and organic human and animal waste. The energy contained in biomass comes from the sun. Through photosynthesis, carbon dioxide in the air is transformed into other carbon molecules (such as sugar and cellulose) in plants. Energy clams stored in plants and animals (due to eating plants and animals again) or in their feces are known as bio-energy. So that the energy contained in biomass is included in the renewable energy class. The types of biomass energy sources are wood originating from forests, forest waste in the form of parts of trees / plants left over from forest harvesting, plantation waste such as midribs,agricultural waste such as rice husk, livestock waste such as cow dung, paper mill waste where the raw material for making paper itself is wood, sewerage waste, kitchen waste such as leftover cooking ingredients, sugar and seeds planted to make alcohol planned for used as fuel such as making ethanol from durian seeds, sugar and seeds grown for biodiesel production such as jatropha seeds or avocados.
All types of biomass have different energy content. Some of them are green wood which has an energy content of 8 MJ / kg which is equivalent to 2.22 kwh (kilowatt hour), the material is dried using an oven 20 MJ / kg equivalent to 5.56 kwh (kilowatt hour), 55 MJ / methane gas kg equivalent to 15,277 kwh (kilowatt hour).
Biomass Conversion
The use of biomass boiler to produce heat simply has actually been done by our ancestors a few centuries ago. The application is still very simple, biomass is directly burned and produces heat. In modern times the heat from combustion will be converted into electrical energy through turbines and generators. Heat from the combustion of biomass will produce steam in the boiler. Steam will be transferred into the turbine so that it will turn and move the generator. The rotation of the turbine is converted into electrical energy through magnets in the generator. Direct combustion of biomass has a disadvantage, so that the current application starts to implement several technologies to increase the benefits of biomass as fuel, explained
Biomass conversion technology certainly requires differences in the tools used to convert biomass and produce differences in the fuel produced
Transesterification is a chemical process that exchanges alkoxy groups in esters with alcohol.
Easy practices for increasing the benefits of biomass are forming into briquettes or pellets. Briquettes or pellets will facilitate handling biomass. The aim is to increase density and facilitate storage and transportation. In general, densification (formation of briquettes or pellets) has several advantages (Bhattacharya et al., 1996)
namely: raising the calorific value per unit volume, easily stored and transported, having uniform size and quality.
Carbonization is a process for converting organic materials into charcoal. in the carbonization process will release combustible substances such as CO, CH4, H2, formaldehyde, methane, formic and acetil acid and substances that do not burn like like CO2, H2O and liquid tar. The gases released in this process have a high heating value and can be used to meet the heat requirements of the carbonization process.
Process
Anaerobic Digestion
that is the process by involving microorganisms without the presence of oxygen in a digester. This process produces product gas in the form of methane (CH4) and carbon dioxide (CO2) and some small amounts of gas, such as H2, N2, and H2S. This process can be classified into two types, dry and wet anaerobic digestion. The difference between the two anaerobic processes is the biomass content in the water mixture. on dry anaerobes has a biomass content of 25 – 30% while for wet types it has a biomass content of less than 15%(Sing and Misra, 2005).
Simply put, biomass gasification can be defined as the process of converting cellulose material in a gasification reactor ( gasifier) into fuel. The gas is used as a motor fuel to drive a power generator. Gasification is wrong
one alternative in the framework of energy saving and diversification programs. In addition gasification will help overcome the problem of handling and utilizing agricultural, plantation and forestry waste. There are three main parts of the gasification device, namely:
Another use of boiler biomass energy is by biochemical processes. Examples of processes included in biochemical processes are hydrolysis, fermentation and an-aerobic digestion. An-aerobic digestion is decomposition of organic matter or cellulose into CH4 and other gases through biochemical processes. The stages of the anaerobic digestion process are shown in Figure. In addition to anaerobic digestion, the process of making ethanol from biomass is classified as biochemical conversion. Biomass which is rich in carbohydrates or glucose can be fermented so it breaks down into ethanol and CO2. However, carbohydrates must be decomposed (hydrolyzed) first into glucose. Fermented ethanol generally has a high water content and is not suitable for its use as a gasoline substitute fuel. This ethanol must be distilled in such a way as to reach ethanol levels above 99.5%
