WO2015111992A1 - Quick-lighting and slow-burning coal - Google Patents

Abstract

The ignition and safety of charcoal has always been problematic as it is slow to ignite and presents various safety hazards on ignition. The invention relates to a treatment for producing charcoal, followed by the application of a sudden temperature change, including a step of immersion in biodiesel and drying. This produces charcoal which is quick-lighting and slow-burning with controlled flames and without any risk of explosion.

Description

 FAST COAL ON AND SLOW COMBUSTION

TECHNICAL FIELD OF THE INVENTION The product obtained belongs to the area of improved vegetable fuels. After obtaining the charcoal, a treatment is applied on which sudden temperature changes are included and followed by an impregnation in biodiesel and drying. Thus obtaining a product with properties of rapid ignition, controlled flame and slow combustion without risk of explosions.

BACKGROUND OF THE INVENTION

It has long been observed that to light a coal fire is not an easy task. This is because the carbon has a fairly high flash point.

Over time, several methods have been proposed for the ignition of coal and even enough facilitators or liquids have been produced to help ignite a coal. These facilitators are usually harmful and toxic substances to greeting, whether they are derived from petroleum or chemicals such as methanol. When coal is used to prepare some food, these substances can contaminate the food we are going to prepare and we can ingest them, causing damage to our health. Even not only when we prepare food, when these substances are used, we run the risk of ingesting them or having any contact that could cause us health damage. These fire starters, apart from their toxicity, are also quite dangerous because when they are lit they produce a very large or uncontrolled flame and can burn us.

Most of the time when working with burning coal, it is very dangerous because the coal explodes and small pieces of burning coal are fired that can burn someone or even cause a fire. It has been seen in the laboratory that this is because the coal has air and / or moisture trapped inside the coal and when the coal is ignited, this causes the air or moisture to expand aggressively, causing the coal to explode.

DETAILED DESCRIPTION OF THE INVENTION

Brief description of the figures:

 Figure 1 is a flow chart of the process applied to obtain the charcoal impregnated with biodiesel.

Figure 2 is a diagram of the process with all the equipment used to obtain the charcoal impregnated with biodiesel.

Charcoal is a solid, fragile and porous combustible material with a high carbon content (of the order of .80%). It is produced by heating wood and plant residues, up to temperatures ranging between 400 and 700 ° C, in the absence of air.

The calorific value of charcoal ranges between 29,000 and 35,000 kJ / kg, and is much higher than that of wood, which ranges between 12,000 and 21,000 kJ / kg.

The wood is heated to high temperatures to obtain charcoal without moisture and little or no air inside, then it is treated with a process of sudden change of temperatures. This sudden change in temperature concludes with the cooling of the carbon by immersion in biodiesel and then it is put to rest.

The first step, in carbonization in the oven, is to dry the wood at 100 ° C to a zero moisture content. The temperature of the oven-dried wood is increased to around 280 ° G. The energy for these stages comes from the partial combustion of part of the wood loaded in the oven or in the pit, and is a reaction that absorbs energy or endothermic. When the wood is dry and heated to around 280 ° C, it begins spontaneously to fractionate, producing coal plus water vapor, mornings, acetic acid and more complex chemical compounds, mainly in the form of tars and non-condensable gases, which consist mainly in hydrogen, monoxide and carbon dioxide. Air is allowed to enter the oven so that part of the wood burns, and the nitrogen in this air will also be present in the gas. The oxygen in the air will be spent burning part of the wood, above the temperature of 280 ° C releases energy, so it is said that this reaction is exothermic.

This process of spontaneous fractionation or carbonization continues until only the carbonized residue called charcoal remains. The temperature reaches a maximum of approximately 400 ° C. However, this coal still contains appreciable amounts of tarry waste, along with the ashes of the original wood. The ash content in coal is about 30% by weight, and the balance is fixed carbon, about 67-70%. An increase in heating will continue to increase the fixed carbon content, eliminating and further decomposing the tars. A temperature of 500 ° C gives a typical fixed carbon content of about 85% and a volatile matter content of about 10%. At this temperature, the coal yield is approximately 33% of the weight of charred kiln-dried wood, not counting the wood that has been burned to carbonize the remainder. The temperature will rise to 700 ° C to reach 92% fixed carbon with 7% volatile material. After being at a temperature of 700 ° C for about 20-30 minutes, the cooling stage will begin. ^m

The cooling stage is carried out in another type of homo but without heating, which is isolated from the outside. When a temperature of 100 ° C is reached in the cooling stage, the treatment of charcoal begins.

The second stage consists of the immersion / cooling of coal (which is at a temperature of 100 ° C) in biodiesel, which will be maintained in a temperature range between 25 ° C-60 ° C. Little by little the hot coal of the first stage is submerged in the biodiesel to cool it. Biodiesel has the main objective of cooling hot coal abruptly, due to the temperature gradient. The cooling stage of charcoal should be done in a time range of 15 to 30 seconds. The cooling biodiesel is recirculated to a heat exchanger in order to maintain the temperature between a range of 25 ° C-60 ° C.

The third stage consists in spreading the coal cooled in biodiesel, over a dry area without air flow, where the bastard has time to rest in order to stabilize its entire structure and the biodiesel is trapped in the porosities of the coal. The coal is left standing for 1 to 2 hours.

With Figure 2, we can explain the process as follows: The wood to be subjected to the carbonization process is taken and introduced into the oven (1). The oven temperature is raised to 100 ° C and maintained until the humidity of the wood is zero. The oven temperature is increased to 700 ° C and maintained for 20-30 minutes. Temperature and control changes are being monitored by the temperature sensor (a). The wood is transported through the belt (e) to introduce it to the cooling room (2), oven type but without heating. When the room temperature reaches 100 ° C (monitored by the temperature sensor h) the coal will be transported through the belt (f) to the biodiesel immersion tank (3). The biodiesel in this tank should be controlled in a temperature range between 20 ° C and a maximum of 60 ° C, which is being monitored by the temperature sensors (b) and (c). This is adapted at the top with an extractor (d) to be able to remove the vapors that are released in this part of the process. Since the coal was left immersing between 15 and 30 seconds in the biodiesel, it is transported with the band (g) to a resting tank (4) where the coal is allowed to stand between a period of 1 and hours. The biodiesel of the immersion tank (3) is recycled, together with the drained biodiesel and collected in the resting stage of the tank (4), in a heat exchanger (5) to be able to keep the biodiesel of the tank (3) between rank of temperature of 20-60 ° C. The recirculation is driven with a diaphragm pump (6).

Apart from the fact that the first stage of the process is carried out in order to obtain the charcoal, it is also important to be able to expel all the air and eliminate all the moisture that is in the pores of the coal, so that later these pores can be replaced with steam of biodiesel and thus eliminate the possible explosions that occur in untreated coal. The second stage is the most important for obtaining the final product. When we are heating the charcoal in the first stage, we cause the air that is trapped in the pores to expand and so the coal has less air inside. When we submerge the heated charcoal in the biodiesel, what we cause is a drastic change in temperature which will cause the little expanded air left inside or pores of the coal to compress. With this compression of the air we achieve that a pressure differential is generated. This pressure differential (generating a vacuum inside and pores of the charcoal) causes the biodiesel that is cooling the coal, mainly on the outside, to be pulled or transferred to the inner part and porosity of the charcoal. At the moment the biodiesel is sucked into the coal, the temperature gradient causes the coal to cool and the liquid biodiesel to heat up and change to steam. What is obtained as a result is that the pores of the vegetable carbon (internal part) have biodiesel in the form of trapped steam. This part of the process is carried out in 15 to 30 seconds in order to prevent the inside of the coal from being saturated with trapped liquid biodiesel. At the end of the process, the internal walls of the carbon pores end up as a fine spray of biodiesel.

At the end of the process you get a coal that can be ignited very easily and very quickly, compared to charcoal without any treatment. It is capable of lighting the coal in approximately 5 seconds with a lighter. This treated coal also has the advantage of lasting on for 10 to 20 more minutes compared to untreated charcoal. This is due to to impregnated biodiesel on the surface and interior of coal. Coal absorbs 10 to 12% by weight of biodiesel.

The extended duration of combustion in treated coal is due to two things. First: the rapid ignition of coal is due to the biodiesel that was impregnated on the surface of the coal, and in order to fully consume this biodiesel from the surface it takes time. Second: as the surface biodiesel is consumed, the coal begins to heat and likewise the biodiesel trapped inside: This biodiesel begins to move outside the coal and begins to consume and support the combustion already presented abroad . Until the biodiesel outside and inside the coal is completely consumed, combustion begins to be carried out with the same coal. This is why the coal treated with the mentioned process lasts between 10 and 20 minutes longer than the untreated coal.

The heat exchanger used, to maintain the cooling biodiesel between a range of 25 ° C-60 ° C, you can use water at room temperature or an air flow (forced convection) to be able to carry out the cooling of the biodiesel. 60 ° C is a set safety temperature in order to keep the cooling biodiesel at a non-hazardous temperature, where it is outside the possibility of ignition.

The biodiesel cooling area will have an extractor that can remove any steam released by heating the biodiesel. These vapors are removed to remove the risk that they themselves may somehow burn and cause a fire.

In the wood carbonization stage, all temperatures are observed with a temperature sensor inside the oven.

The coal treated with the aforementioned process is capable of being used as a fire facilitator for any desired occasion in which you want to perform a combustion It can be used as a facilitator in the ignition of untreated coal and a fire starter.

There are currently some products for the ignition of coal on the market. .

Some of these are made from alcohol in the form of gel, fuel oil or petroleum-derived materials so that when they are ignited they release characteristic fumes. There are also carbons already impregnated with these products. However, none is made from biodiesel.

A disadvantage of some of them is that they ignite faster than required, so that coal is consumed quickly without grilling, which makes them unhelpful for some activities where coal consumption is required to be slow.

The proposed carbon treated with biodiesel does not release fumes or odors, apart from its toxic emissions at the time of combustion are very low. It lasts 10 to 20 minutes longer on compared to an untreated coal. It does not cause small explosions to be on because it has no air and moisture trapped inside. It is capable of lighting the coal in approximately 5 seconds with a lighter. When the coal is ignited, a controlled flame is produced and. moderate [ ^1] "Carbonization processes." FAO Document Repository.

Department of Montes. Web. 18 Jan 2014. <http://www.fao.org/docrep/x5328s/x5328s05.htm>.

Claims

one . The present invention calls for a novel process to manufacture natural coal of rapid ignition, slow combustion and free of burning ash microexplosions, comprising: a) Entry of a solid body with high cellulose content, greater than 60%, in a chamber of heating; b) exposure for at least 30 minutes of the body at 140 degrees Celsius; c) exposure of the same body for at least 30 minutes at 700 degrees Celsius in said heating chamber; d) temperature monitoring and control through a thermal sensor connected to a data processor; e) transport of the body by a band to a cooling chamber where it will remain until its temperature reaches 100 degrees Celsius for later transport to a container where it will be submerged for at least 15 seconds in a liquid body based on methyl esters derived from fatty acids of controlled temperature between 20 and 60 degrees Celsius; f) transport of the solid body by a drying and packaging band at 40 degrees Celsius. 2. A method as described in claim number 1 wherein the solid body reaches the temperature of 700 degrees Celsius by combustion at controlled air flow. 3. A method as described in claim number 1 where the body is impregnated with methane! before packing, after the process of cooling to 40 degrees Celsius.