Manufacture of solid fuel from water hyacinths
The present invention refers to a briquetting process with the aim of replacing charcoal and stopping the destruction of forests, as is the case in Madagascar. The method of the present invention provides an economical and high energy quality briquette that can be used on a daily basis in place of coal as a household fuel.
The briquette obtained is a 100% natural product and an alternative to conventional heating products, maintaining at least the same or even better performance. In addition, the process allows to exploit a raw material that is abundant in certain countries and that is in disuse and sometimes even inconvenient because the water hyacinth is an invasive plant that suffocates bodies of water and causes fish to disappear in favor of other pests such as rats that spread disease.
For an industrial harvest, hay harvesters are used to harvest the hyacinths. The hyacinths are then ejected from the back of the mower to form a kind of floating carpet. The barges are arranged along the floating mat to frame the hyacinth mat with a vertical net (including floats for the upper part and weights for the submerged part). Once the mower has passed the first strip, the nets are connected to a factory entrance and towed using a pulley system to bring the cut hyacinths directly into the factory.
The hyacinth enters the plant via a conveyor belt that first drives it through a grinder made of rotating blades. This step allows a kind of first cleaning to be carried out in order to eliminate a large part of the sand and earth contained in the roots of the hyacinth. The hyacinth thus crushed will pass through a screen that will carry out a sort of sieving finer than the mill. The plant thus cleaned can finally be taken to a storage tank. The crushed and screened hyacinth is then dried using a biogas-fed dryer. Once dry, the fibers are molded and compacted into briquettes. The briquettes are then packed into 20 kg bags which are then stored to be transported by trucks.
In this case, the method comprises an additional step consisting of toasting the briquette. The roasted briquette has a relative humidity equal to 7%, an ash content of the material of 23%, a dry PCS of 15% and a dry PCI of 15%. The roasted briquette has a nitrogen content of less than 1%, typically 0.95%.
The process of the present invention makes it possible to obtain a briquette of high energy and economic quality that can be used on a daily basis instead of coal as a domestic fuel and that also helps to preserve flora and fauna.