Prospects for the application of the “pyrolysis” process In the aim to obtain heat and electrical energy or “True pyrolysis cauldron”.
This article will focus on the “pyrolysis cauldron” that has become widespread in recent years, which is applying for processing solid fuel of plant origin, including pellets, briquettes, etc.
Let’s start with the origins of the name “pyrolysis cauldron”. The essence of the “pyrolysis” reaction is disclosed in Wikipedia, in short, as a result of biomass pyrolysis, two main products are obtained:
- Carbon residue (charcoal)
- Vapor-gas mixture (combustible pyrolysis gas), which in turns can be separated into condensable (liquid pyrolysis products) and non-condensable products (gaseous pyrolysis products)
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The main question is that the so-called “pyrolysis cauldrons”, in essence, are cauldrons with “two-stage combustion”, which are inherently use a fundamentally different reaction, in comparison with “pyrolysis”, this reaction is called “Gasification”, (the nature of the reaction is disclosed in Wikipedia), as a result of biomass gasification, two main products are obtained:
- Ash residue (ash)
- Synthesis gas (combustible generator gas), which in turns cannot actually be condensed at a natural temperatures (+ 10-40 ° C)
As a result, a fair question arises for the manufacturers of the so-called “pyrolysis cauldrons”: “Where is the carbon residue that should be obtained as a result of the pyrolysis reaction”, if they answer: “The carbon residue burned out as a result of the reaction”, then this means that their reaction “not pyrolysis”, but “gasification”!
The saddest thing is that in the result of rejection of fossil fuels, in order to switch to the usage of renewable energy sources, a lot of so-called “kulibins” are appeared on the market, who do not understand the essence of the reactions, but only operate the trendy word “pyrolysis” – calling their cauldrons of two-stage combustion the “pyrolysis cauldrons”.
What is a “real pyrolysis cauldron”? “Pyrolysis cauldron” can be called a pyrolysis installation, that can process any carbonaceous materials to obtain a carbonaceous residue and gaseous pyrolysis products. A classic example that is known by many is a charcoal or carbon residue from wood pyrolysis, obtained using a pyrolysis installation or charcoal kiln.
Liquid products of wood pyrolysis in ancient times were used for lubrication, in the roofs` construction, nowadays they are used to get heat energy, which in turns, is used for different stages of the pyrolysis in the environmentally friendly charcoal kilns.
The theory of the process defines the classical operation of the pyrolysis process (or pyrogenetic processing of biomass) as drying the biomass and heating it without air access to the temperature of thermal decomposition. As a result of this process obtained the solid residue (wood charcoal) and gaseous (condensable and non-condensable) pyrolysis products.
In contrast to the process of “pyrolysis”, the process of “gasification” is a biomass combustion with a lack of air. The final products of that process are solid residue (ash) and gaseous products of incomplete combustion (generator gas) are formed.
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The temperature of exhaust gases during pyrolysis in real pyrolysis boilers is more than 1000 ° C, which makes it possible to use them for various thermal processes: preliminary extraction of raw materials, heating of premises, drying of bricks, overheating of steam for activation, etc. So gaseous pyrolysis products in such a pyrolysis furnace do not escape into the atmosphere and do not pollute the environment, but can be used to supply power to the pyrolysis process itself, which makes the process itself much more efficient and less costly, or for the needs of the enterprise itself.