Water Hyacinth Pyrolysis For Electricity And Charcoal Production

 

Map of distribution of global water hyacinth infestation

Water hyacinth has become a global concern as the most disturbing and invasive aquatic weed. The impact of water hyacinth losses covers the environment, economy and even social conditions experienced by many countries as a result of the water hyacinth attack. Economically, the losses due to water hyacinth are also very large, reaching hundreds to thousands of millions of dollars. Pyrolysis of water hyacinth for electricity and charcoal production is one solution to overcome the water hyacinth attack. In this way, it is hoped that the growth of water hyacinth can be controlled and reduce the environmental impact significantly. This is because the speed of attack from the fast growth of water hyacinth can be balanced with the speed of the biomass requirement for the pyrolysis process that produces electricity and charcoal.

The electricity generated in addition to operate or running the pyrolysis unit can also be used for various needs of the surrounding community. Meanwhile, the charcoal produced can be used for energy and agricultural applications, or in general the motivation for charcoal (biochar) production is as shown in the scheme below. And to facilitate handling both storage, transportation and use, the charcoal can be compressed / densified into pellets or briquettes. The need for energy or fuel for the surrounding community for cooking and so on, can use the charcoal that has been compressed into the pellets or briquette. If the community previously used firewood obtained from the forest illegally, then the charcoal pellet or briquette is also a solution to the problem of forest destruction.

 

The use of water hyacinth as a bioenergy is the best option and is most recommended by prominent experts and researchers around the world. Pyrolysis is one way or method of bioenergy production. It is true that water hyacinth also provides environmental benefits, namely phytoremediation, but with uncontrolled development, the aspects of the losses incurred are far greater than the benefits obtained. This requires good management so as to produce optimal benefits. In a number of cases even the water hyacinth creates silting which causes the volume and discharge of water, even though the water is used for hydroelectric power plants. This causes the hydropower plant to have less water supply and disrupt its operation. So that the use of water hyacinth for electricity production with pyrolysis will again increase the supply of electricity produced and at the same time overcome the volume and discharge of water for the hydropower plant. Basically, maintaining a balance between the environment and economic aspects must be made in such a way as to become a sustainable activity so that it is in line with the bioeconomic era. Bioeconomics is defined as knowledge-based production and using biological resources or living things to produce products, processes and services in the economic sector within the framework of a sustainable economic system.

Modernization Charcoal Production with Continuous Pyrolysis

Charcoal production and charcoal marketing have not been treated by strict rules such as wood pellets. This is mainly due to the large number of charcoal producers, with a small average production and traditional production technology. In addition, the market or buyer also does not require large volumes and long-term contracts. The quality factor remains an important standard, especially for the export market. But it could be that more stringent rules will also apply to production and marketing, given the potential damage caused. The low conversion of traditional charcoal kiln, which is an average of 15%, makes the need for wood raw materials extra, so that to produce 1 million tons of raw materials is needed about 6.5 million tons of wood. The approach to using efficient technology is increasingly urgent especially to serve large and continuous needs. Pyrolysis or continuous carbonization is the solution to this, with a conversion rate to charcoal reaching 30% or almost one third. With this efficient technology, only 3 million tons of wood is needed, or only half that means saving about 3 million tons of wood raw material.

Another motivation for using continuous pyrolysis technology is the high efficiency of energy savings that can be obtained. In charcoal production traditionally more than 60% of energy is lost during the production process. This can be illustrated in making charcoal from coconut shells. Conversion from raw materials to charcoal is only 15-25% in the process of traditional carbonization / pyrolysis. For example, we take a conversion of 25% (the best estimate), with a raw material of 10 tons of coconut shell, then 2.5 tons of charcoal are produced. Coconut shell with a heating value of around 4,500 kcal / kg, meaning that 10 tons of raw material is 45,000,000 kcal. While coconut shell charcoal with a heating value of around 8,000 kcal / kg, then 2.5 tons of charcoal will have a heating value of 20,000,000 kcal / kg. Based on these calculations more than 50% of energy is lost or is only wasted, ie 25,000,000 kcal. If the conversion to charcoal is lower or 20%, the energy loss is even greater, namely 29,000,000 kcal or more than 60%. Of course it is very inefficient and a lot of energy waste.

Whereas in the continuous pyrolysis process almost all energy can be utilized. Syngas and biooil are two types of by-products from pyrolysis that can be used as energy sources. Based on this, not only is conversion increasing, resulting in a reduction in raw materials which are also used by side products that can be used as energy sources. At present there are very few people who are thinking of utilizing the energy lost during the carbonization / pyrolysis process, this is because most people only think about how to increase the conversion to the charcoal. The loss of energy during the carbonization process is unknown or not realized by mostly charcoal producers in particular.

The use of 'lost energy' when the carbonization / pyrolysis process becomes another form of energy is certainly very good and adds value to its benefits. Electricity and heat are the two most needed forms of energy, so the conversion of 'lost energy' or pyrolysis / carbonization byproducts to become electric and heat energy is the best use scenario today. A number of regions or regions in the world still have low levels of electricity access. Africa, for example, on average has a low level of access to electricity, which is less than 30%, whereas in this region is the largest charcoal producer in the world which reaches 50% of global global production. By using continuous pyrolysis, this area, in addition to being the largest charcoal producer and even with a higher conversion, will also have access to electricity with the construction of a power plant fueled by the pyrolysis / carbonization by-products.

Charcoal is an energy product from biomass processing, especially wood. Wood charcoal has been known for a long time and is produced in a number of places. The process of producing wood charcoal is generally traditional, takes a long time and the quality is not uniform. According to FAO, global wood charcoal production in 2015 was recorded at more than 50 million tons and about half of it was produced in Africa. That means with the assumption that the conversion rate of 15% requires biomass, especially wood as raw material, as much as 333 million tons every year with 167 million tons coming from Africa. If the conversion rate to charcoal can be increased to 30% or two times, then the need for raw materials will decrease drastically or only half, namely 167 million tons globally and 83.5 million tons from Africa. What a very significant savings effort.

Every year Europe imports 1 million tons of charcoal, as well as Saudi Arabia and Middle Eastern countries import more than 1 million tons of charcoal. Saudi Arabia and the Middle East mainly use charcoal to roast lamb, a favorite food there. The use of charcoal in general is mostly the household sector with retail distribution. In addition charcoal is also used for metallurgy, agriculture (biochar) and activated charcoal (activated carbon) raw materials.