Continuous Pyrolysis for the Activated Carbon Production Part 2

Activated carbon production can be done in two ways, namely physical and chemical activation. Both physical and chemical activation require pyrolysis (carbonization) in the activated carbon production process. The difference about the sequence, in the use of the pyrolysis unit (carbonization) in the activation process is the physical activation of the pyrolysis unit (carbonization) for charcoal production which is then activated using steam or CO2, while the chemical activation of the pyrolysis unit (carbonization) is used for charcoal production from raw materials previously chemically activated like with H3PO4, ZnCl2, KOH. Other differences in physical activation using temperature for activation are higher, namely the range of 800-1000 C while the chemical activation uses a lower temperature, which is around 150-200 C only. Activated carbon products or yield that are produced chemically are more than those produced physically, which are around 3: 1.

The advantage of using a continuous pyrolysis unit for activated carbon production primarily increases the efficiency of the production process and the quality of the products. Efficiency is very important for a production activity. The efficiency of the production process is derived from the use of pyrolysis by-products that can be used to produce heat and even electricity. As an example of physical activation that uses a high operating temperature, excess syngas can be used to reach that temperature. Biooil produced can produce steam. Charcoal products produced from a continuous pyrolysis (carbonization) unit also do not need to be cooled and can be activated directly, so that their energy needs can be minimized. So that the activated carbon production should be an integration between the pyrolysis unit (carbonization) and its activation unit.

While in the chemical activation process, pyrolysis (carbonization) byproducts can also be used for the production of activated carbon. The activation process that uses a temperature that is quite low at 150-200 C can use excess heat from the pyrolysis process for its heat source. While excess syngas can be used to produce electricity for the production of activated carbon or sold to other parties such as other industries or PLN. Biooil can also be used for burner fuel or purified again for the production of vehicle fuel and so on. Continuous use of pyrolysis (carbonization) will also produce high quality, standard and stable product quality, this is because the operating conditions in the unit can be easily and accurately controlled, such as heating rate, residence time and temperature.

While in charcoal production (carbonization) traditionally operating in batches, in addition to a lot of energy loss also produces a lot of smoke which causes air pollution. The loss of energy during the traditional process of carbonization (pyrolysis) can even reach more than 60% meaning that more than half of the energy is only wasted, for more details can be read here. Of course this is very unfortunate, the activated carbon plant which should be able to operate very efficiently and economically, becomes wasteful and expensive. The effect of this is of course on the depletion of the profits obtained by the business. Within a short time it is expected that activated carbon factories will use continuous pyrolysis (carbonization) to increase efficiency, environmental and economic aspects.

Continuous Pyrolysis for Palm Oil Mills

A number of regions have been over-supplied with electricity so it is not possible to add or build new power plants. Making a new plant will only be in vain because the electricity production cannot be utilized or absorbed by the user. Based on this, electricity production in a number of areas must be limited and diversified into other products needed. These other products are products whose needs are still not met. Another thing that can be done is to increase the efficiency of a production process. When the efficiency of a production process is improved and produces the products needed, of course the business benefits increase. Besides that, when all the waste can be processed, it becomes a production unit that is zero waste and environmentally friendly.

Palm oil mills are very numerous in Indonesia and Malaysia, the number reaches more than 1000 units, while Thailand also begins to follow the planting of oil palm. At present some of the palm oil mill effluents have not been processed such as empty palm bunches, palm shells and fronds. The palm oil mill that has been operating can be increased efficiency and the production of by-products that provide additional income. This can be done by using a continuous pyrolysis unit for both electrical and heat energy sources and the production of various by-products in the form of charcoal, biooil and biomass vinegar. The three by-products can be sold or marketed and become an additional income for the palm oil mill which is quite attractive.

Conventional Energy System in Palm Oil Mill

Improved Palm Oil Mill with Continous Pyrolysis System

Palm oil mills also do not need to be bothered with the problem of waste, especially solid waste if everything can be processed and very profitable. Meanwhile, from the environmental aspect of a palm oil mill that is zero waste and environmentally friendly, it is certainly the dream of all the palm oil mill owners. The community and the surrounding environment which is not disturbed by the palm oil mill that is because of its pollution is also a condition desired by the palm oil entrepreneurs. By using the continuous pyrolysis, the air pollution generated is very minimal or far from the required threshold, so that the environment and the surrounding community can be accepted. If the palm oil mills have used continuous pyrolysis, it will also be economically attractive.

Charcoal produced also has many benefits. Technically, charcoal is a stable fuel so it is easy to store and does not decay or is eaten by termites. Charcoal can be used for energy sources directly easily, or converted to other fuels, for example converted into liquid or gas fuel. The condition of fossil fuels, especially petroleum which is increasingly depleted, demands the diversification of energy, such as Indonesia which is predicted to run out of oil in 10 years or in 2028. Likewise, biooil can be used immediately, or upgraded to better fuels, such as vehicle fuel. While biomass vinegar can be used for fertilizer, biopesticides and upgraded to biophenol and wood adhesive.

Continuous Pyrolysis Unit for Activated Carbon Production

Production of activated carbon requires charcoal as raw material. Charcoal production will be more effective and efficient by continuous pyrolysis (carbonization). In addition to the high quality charcoal produced can also produce electricity and steam production for the activation process. Of course this makes high efficiency of the production process. Whereas in terms of environmental aspects, it is also very environmentally friendly because of smoke pollution during the process of pyrolysis (carbonisation) can be minimized below the threshold. Methane emissions that are very damaging to the ozone layer also did not occur.

The process of pyrolysis (carbonization) with a temperature of around 400 C with a product in the form of charcoal can immediately proceed with activation. Activation with 700-1000 C operating conditions can be done directly by raising the temperature. If the excess syngas is used for electricity production, then biooil from pyrolysis can be used to fuel in steam production. Excess electricity can also be sold to industries or to electricity companies. Whereas if all sources of energy are used for the production of activated charcoal (activated carbon), the consumption of heating oil can be minimized and even eliminated. Activated carbon production with all the energy can be supplied by itself is certainly very interesting and economical.

The problem with traditional charcoal production is the problem of smoke pollution and the amount of energy lost. Smoke pollution can be directly identified and can be easily felt, but the problem of energy loss is usually not noticed and generally do not know. Of course this is very unfortunate, let alone energy is one component of high costs in a production process. Is there really an energy loss? And how much energy is lost? Of course we need to look in detail at the carbonization process (pyrolysis) to answer these questions.

 Conversion from raw materials to charcoal is only 20-25% in the process of traditional carbonization / pyrolysis. For example, we take a conversion of 25%, with a raw material of 10 tons of coconut shell, 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 should be avoided. This can also happen for carbonization of various other raw materials for activated carbon, such as palm kernel shells, wood, and so on.

Continuous pyrolysis is the best solution for charcoal production and also the production of energy that can be used for the activated carbon production process itself. The activated carbon factories that have been established can upgrade the technology especially on the side of charcoal production and energy fulfillment. The more efficient of a production will be the more economical the business. While the pyrolysis or carbonization process is also still produced by-products namely biomass vinegar (pyroligneous acid / liquid smoke) which can be used as plant fertilizer, biopesticides to raw materials for chemicals, especially biophenol and wood adhesive.