Water Hyacinth Pellet or Briquette Production?

 

Biomass Briquette

 

Wood pellet

Market absorption or the existence of buyers of the products produced is very important for a production. Certain products are needed because it can be said that they are basic needs such as food, energy and so on. Biomass fuel is a renewable fuel or energy source that is increasingly sought after and needed, especially by industry. Pellets and briquettes are products of biomass densification with use primarily as fuel or energy sources. With this compaction, handling, storage, transportation and use becomes easier, cheaper and safer. As we all know, water hyacinth is an aquatic weed that harms the environment a lot, but how to use this waste so that it is beneficial or minimizes its environmental impact? Is compacting into a pellet or briquette an effective solution? And which is the best made pellet or briquette?

 Water hyacinth is arguably the most invasive aquatic weed in the world today. A number of disadvantages associated with the rampant water hyacinth are real and have a major impact and have been experienced by many countries in the world. In general, the losses of water hyacinth weeds have a major impact on the environmental, health, transportation, energy and economic sectors. More details include:

a. Siltation of water areas namely rivers, lakes, lakes and so on. Silting causes the volume and flow of water to decrease. The reduced volume and flow will certainly have a serious impact on those who use these waters as a source of agricultural irrigation, hydroelectric power, drinking water, industrial processing water and transportation facilities.

b. The dense roots of water hyacinth will not only obstruct the flow of water so that a number of garbage or organic waste collects at the location. In addition, the roots of water hyacinth that absorb nitrogen in the atmosphere will disturb the fish and a number of aquatic biota, because the oxygen supply is disrupted. The source of protein in the form of fish will also be drastically reduced. The location is also a source of disease such as mosquito breeding grounds and is also a home for poisonous snakes.

c. The waters that have been covered by water hyacinth also cannot be used as a means of transportation and a medium for aquaculture. The tourism sector which utilizes the water areas also will decline and stop.

d. With normal volume and flow, these water areas should also be able to control water and flood control which may come at any time, but with the shallower, even water flows become clogged and the surface of the water hyacinth covered waters, the volume and discharge that can be controlled is getting smaller, consequently causing the impact of flooding in a number of places.

e. Water evaporation due to closed water surfaces is also getting higher (evapotranspiration). A number of studies stated that water hyacinth plants resulted in high water evaporation, which is about 3 times normal open water. Lakes or reservoirs as water sources will also be affected due to the decrease in water volume due to high evaporation. In addition, it will also reduce the amount of light in the waters which causes low levels of oxygen solubility. This affects the life of the creatures (aquatic biota or biodiversity) in the water.

Water hyacinth has become a global problem that occurs in five continents with more than 50 countries experiencing it. Africa and Southeast Asia have been particularly hard hit. Egypt, Ghana, Nigeria, Ethiopia, Uganda, Senegal are some of the countries in Africa experiencing the worst water hyacinth problem. Like the second largest lake in Africa, Lake Victoria in Uganda, East Africa has also been filled with water hyacinth. Meanwhile in North Africa the most serious problem in Egypt is in the Nile basins. Likewise in Europe, namely the Guadiana river valley in Spain. Likewise in the Godavari delta and the Brahmaputra river in India. This includes large countries such as the United States and China.

Map of the distribution of water hyacinth attacks globally

Map of distribution of water hyacinth attacks in the United States

 

Map of distribution of water hyacinth attacks in the Hawaiian Islands, United States

 

 

Map of distribution of water hyacinth attacks in China. Black is the worst.

At first, water hyacinth originating from the Amazon river, Brazil was popularized in the mid-19th century as an ornamental plant with beautiful flowers. But not long after that it turned out that water hyacinth had become the fiercest aquatic weed ever. The 80s were the years when a number of countries began to realize the problem of water hyacinth. A similar case as in the golden snail, this animal was originally also similar to ornamental fish in aquariums. But after the leak, the golden snail eggs hatched in the waters and now the golden snail is also a disturbing water pest. Indeed, at first this happened unconsciously or anticipated beforehand, until when the impact of the problem grew bigger and even dangerous, the awareness began to grow. The cases mentioned above should be able to become valuable lessons so that they are not repeated in the future.

Water hyacinth pellet produced in Indonesia, photo taken from here

Ethiopian Ambassador to Indonesia Admasu Tsegaye when meeting with Director Sido Muncul Irwan Hidayat, Photo from here

A number of leading experts and specialists in aquatic weeds around the world have also discussed and tried various countermeasures. A number of frameworks and action plans have been formulated and implemented in these locations. However, the water hyacinth problem cannot be solved completely and permanently. Water hyacinth can also be an indicator of the level of water contamination or eutrophication activity, which is an indication of contamination of aquatic land, by detergents and the like, under normal conditions the growth of water hyacinth takes about 52 days while in polluted water conditions it becomes less than half, which is 22 days only. . The characteristics of plants that can reproduce very easily and whose seeds last for decades are indeed very difficult to eradicate completely, even if it is said to be impossible.

But maximizing the effort so that the water hyacinth is controlled seems more realistic. The speed of eradicating water hyacinth must also be faster than the breeding rate. And it could be that the eradication is done by several combination methods so that the results are effective. Combination of physical / mechanical methods (long arm / short arm excavator, multi-function dredger / dredger, truxor, harvester berky, dump truck, amphibious Long Arm, tugboat, and pontoon), biology (water hyacinth predators and pests) and even chemistry ( such as the use of 2,4-Dimethyl Amine 58% - dose 4 kg / ha) can be done for this effort.

Based on the strategic functions of waters, especially lakes, which are widely available in Indonesia, the prevention of water hyacinth is a national priority, especially since most water hyacinth attacks have even reached 70% of the surface of the water. Among the priority lakes are Lake Toba, Maninjau, Kerinci, Jampang, Rawa Pening, Limboto, Tondano, Tempe, Poso, and Sentani. An indication of the criticality and urgency of these lakes is that some of them can turn into land if not treated immediately. In addition to that in Indonesia, the problem of water hyacinth is also a joint problem across departments or ministries such as the Ministery of Environment, Ministery of Public Works and Human Settlements(subordinat : River, Lake Sector, Directorate General of Water Resources), Fisheries and Marine, Agriculture, and Health, while for the global level Food and The Agriculture Organization (FAO) is one of the institutions that also deals with this problem. This indicates that the water hyacinth problem is not a simple problem and easy to handle.

With the productivity of water hyacinth reaching 300 tons / hectare / year, high speed is needed to reduce the spread of weeds in these waters. For example, with a water hyacinth cleaning speed of 8 hectares / day with a lake area of ​​2000 hectares, 2,400 tons of wet water hyacinth are produced every day, and every month 200 hectares of water hyacinth are cleaned or 2400 hectares per year, which means that periodically the growth of water hyacinth continues to be controlled well. With water hyacinth moisture content reaching 80%, when it is compacted by means of briquettes or pellets, it needs to be dried to about 10% moisture content. Each ton wet of water hyacinth will produce approximately 300 kg of water hyacinth or that means that with the cleaning speed above 720 tons / day of dry water hyacinth or with a moisture content of 10% is obtained. The remaining water that is separated or disposed of per ton of water hyacinth reaches 700 kg per ton or 1,680 tonnes / day. Liquid waste, which is likely to contain a lot or is rich in organic substances, also has the potential to be developed into biogas. The need for energy is indeed very large, plus the use of renewable energy, especially biomass-based, continues to be encouraged. With the production of biomass briquettes as above, namely 720 tonnes per day or 18,000 tonnes / month or 216,000 tonnes / year, of course this is a large enough amount to replace the use of fossil fuels such as coal, oil and gas.

Industrial briquette, puck shape

Although both types of fuel products, both pellets and briquettes, can be produced from water hyacinth waste, which can also depend on the demands of the product users. But technically, briquette production is easier and cheaper than pellets. The density of the briquettes can also be adjusted according to the needs as well as the size of the briquettes. Particle size and moisture content in briquette are also looser than in pellets, for more details can be read here. Even organic waste in the form of sediment (sludge) from the roots and leaves of water hyacinth at the bottom of the water can be taken for briquettes. The sludge briquettes containing humic acid can later be used as organic fertilizer. The preparations for the production of pellets and briquettes can actually be said to be almost the same, such as size reduction / down sizing, mechanical extraction to separate water, drying to 10% moisture content and finally the compaction (biomass densification).

Sludge briquette

Apart from a number of detrimental factors above, there are a number of environmental benefits that can also be obtained from the water hyacinth plant, namely cleaning polluted water (phytoremediation) such as reducing COD, increasing pH, absorbing nitrogen and phosphorus from wastewater. Maximizing benefits and minimizing losses is an approach in overcoming the water hyacinth. With this pattern, the population of water hyacinths must be continuously limited so that there is a good environmental balance. With a comprehensive and accurate statistical analysis, it can be studied in depth the use of water hyacinth as fuel for both briquettes and pellets. Several things that can be compared are fish production before and after water hyacinth infestation, as well as the capacity of electricity generation, tourism and so on. Compensation for economic benefits that are worth it can be a driving force for efforts to use the water hyacinth so that the main mission of saving the environment due to water hyacinth weeds can actually be achieved according to the expected goals. The balance of economic and environmental factors with the production of sustainable briquettes or pellets is expected to be an attractive and effective solution to control the development of water hyacinth.

Increasing Biogas Production With Biomass Briquettes

For example, activated carbon which has much more pores than ordinary charcoal, or one spoon of activated charcoal is estimated to have a surface area like the area of ​​a football field. With this surface area, activated carbon can adsorb much more molecules than ordinary charcoal. That is what makes activated carbon used by many industries, for more details, you can read it here. The activation process is the process of creating or opening the pores of charcoal so that it has a large surface area. Likewise with the biomass briquetting process, due to the strong pressure and high temperature of the briquetting process with a mechanical press, the micro pores of the biomass will open. The opening of the biomass pores will increase its absorption power. It turns out that according to research at Aarhus University Denmark, the use of biomass briquettes, especially straw briquettes, has been able to significantly increase biogas production. Every 1 tonne of straw briquettes added has increased the biogas production by an average of 400 cubic meters. With a biogas caloric value of around 4500 kcal / m3, each tonne of addition of straw briquettes will increase calories by 1,800,000 kcal in the form of biogas. Meanwhile, every 1 m3 of POME will produce about 25 m3 of biogas.

The research was conducted on a continous stirred tank reactor (CSTR) biogas type so that the effort to maximize the substrate mixture of biogas was carried out mechanically. CSTR for biogas production is still rare in Indonesia and the Southeast Asia region today, but is common in Europe. The addition of briquettes to the biogas reactor also means adding organic material as raw material for biogas production. But with this form of briquette which has the ability to absorb much more water or 10 times that of bulk straw without be briquetted, which causes microbes to penetrate far more through the micro pores of the straw briquettes, as a result the fermentation process is more perfect. Based on these experiments, the biogas production reached the optimum level at the addition of 10% straw briquettes to the reactor volume. The addition of straw briquettes of up to 10% apparently did not interfere with the performance of the stirrer motor and the straw briquettes because the micro pores absorbed water optimally and did not create floating material that covered the surface of the reactor. 

For biogas factories in Indonesia, especially Southeast Asia in general, especially those that use CSTR for biogas production, of course the above can be a reference and guide for trials to increase biogas production by adding biomass briquettes. In the above case, the straw used in Denmark uses straw from the wheat plant because it is abundantly available there, while in Indonesia and Southeast Asia, rice straw is widely available. The properties of wheat straw and rice straw are so similar that it is also predicted that they will produce almost the same volume of biogas. But if the biogas unit is for example in palm oil mills, biomass sources such as mesocarp fiber, empty bunches and palm leaves can be used as raw material for the briquettes. The biogas unit commonly used in palm oil mills in Indonesia and Southeast Asia using palm oil mill effluent as raw material is a covered lagoon which is not equipped with a mixer. For this type of reactor, one of the efforts to increase biogas production is by making the operating conditions thermophilic. The heat from the biogas power plant can be used to reach this temperature. Can biomass briquettes increase biogas production in covered lagoon reactors? The answer still needs further research.

Why Produce Electricity From Biogas Using Gas Engine Generators? Not With Gas Turbine Generators Or Steam Turbine Generators

  

The need for this type of power plant is always related to capacity, a number of technical factors and the investment costs required. Turbine with generator is a type of generator which is commonly used in industry, especially steam turbine and gas turbine. The grouping of turbine types above is based on the principle of operation and the fluid that moves them. At a palm oil mill, almost all of the electricity is generated from a steam turbine generator. In addition to electricity production, the steam generated from the boiler is also used to process fresh fruit bunches (FFB) to produce crude palm oil or CPO.

Processing of palm oil mill effluent (POME) into biogas and subsequently mostly used for power generation. Almost all of the electricity from biogas is used to meet the needs outside the palm oil mill and the surrounding community. With the potential for palm oil mills in Indonesia that are estimated at more than 1000 units supported by 15 million hectares of palm oil plantations, the potential for electricity generated will be more than 1.5 GW. Approximately 0.7 m3 of liquid waste is produced by the palm oil mill from each tonne of FFB processed. Biogas usually consists of 50-75% methane (CH4), 25-45% carbon dioxide (CO2), and a number of other gases. If wastewater management is not controlled, methane in biogas is released directly into the atmosphere. As a greenhouse gas (GHG) methane has a 21 times greater effect than CO2. The production of electricity from biogas from palm oil mill effluent (pome) is also an effort to reduce environmental hazards. The electricity production from the biogas all uses a gas engine generator and none of them uses a steam engine generator. This is because the production of electricity with steam turbines is not only more complex but also less efficient. The gas engine generator is a power plant that is most suitable for the conversion of biogas to electricity. Gas engines whose engines are similar to gasoline engines, with only the change of fuel into gas (biogas) or similar to vehicle engines such as public buses that run on gas fuel are also more familiar to most people. 

Gas turbine generators are generally used for large capacity power plants. Gas power plants in Indonesia generally use gas turbine generators. Gas turbines are equipment that uses high pressure combustion gases to turn a turbine that can be connected to a generator to generate electricity. Apart from generating power, gas turbines are also used in boats, racing cars and jet planes. The main parts of gas turbines include: compressor, combustion chamber, gas turbine and workload. Each part or segment has a number of critical components which are connected in one axis. During the operation of the gas turbine, some of the power generated by the turbine is used to drive the compressor. The large capacity and technical factors of gas turbine generators make the unit expensive and not used for the production of electricity from biogas. The electricity capacity of biogas from wastewater treatment like POME is not too large, that is, for a palm oil mill with a capacity of 30 tonnes / hour of FFB it will produce about 1 MW of electricity and its multiples. This is the reason why gas engine generators are used in biogas power plants, especially in the palm oil industry.

Rice Husk Pellets or Rice Husk Briquettes?

 

Rice husk truck, photo taken from here

Indonesia's rice production in 2008 is estimated to reach 59.9 million tons of milled dry unhulled rice with a composition of 25% husk, which means that the potential for husks reaches 15 million tons / year. Although the amount is abundant but generally the utilization is still not optimal, this is because the rice husks have low bulk density and low calorific value due to the high ash content. So that the rice husks can be utilized optimally, one solution is densification. With this compacted rice husks can be easier to use, economical in transportation and facilitate storage. A large pile of rice husks also has a strong tendency to burn. The dry husks easily fly like dust so that high concentrations in the room will be flammable and dangerous. Compaction of rice husks will make rice husks larger, denser and heavier so that they do not fly easily or in other words, reduce the risk of the fire.

The need for biomass fuel has increased recently. This encourages the use of agricultural and wood processing industrial wastes. These wastes were initially not utilized and tended to pollute the environment, but now they are being processed a lot for the production of biomass fuels. A positive effort, of course, because in addition to minimizing environmental problems caused by waste, it is also a profitable business activity. Production of biomass fuel can start from medium capacity to large capacity, from a capacity of several hundred tons or thousands of tons per month to hundreds of thousands of tons per month. Although the potential in Indonesia is large, generally the use of these wastes is not maximized so that commercial biomass fuel production is generally still low. 

 Briquettes and pellets are the products of the biomass densification technology. Basically, briquettes and pellets have their own characteristics, although physically they can be easily recognized by the size of the briquette that are bigger than the pellets. The briquette technology is also more diverse than pellets, so that is the case with the output in the form of the briquette product, for more details, please read here. For rice husks for use as industrial fuel, industrial production of briquette with a mechanical press is most suitable. This is because it is technically easier and economically cheaper. Although the rice husk can also be pelleted, it will cost more. This is because rice husks are very abrasive due to the large ash content with the main constituent component in the form of silica. The ring die and roller press on the pelletiser will wear out quickly due to the abrasive material. Production of rice husk briquettes with a screw extruder is also possible and possible, even a number of countries such as Pakistan, Nepal, Bangladesh, Vietnam and Thailand have also done so. But with these abrasive materials the production costs are also high. The briquettes produced by the screw extruder are also long so they usually need to be cut into pieces for use so that the use of the screw extruder also becomes less practical. With a mechanical press, the briquette size can be cut into small pieces easily, making it easier to use.