Biochar to Increase Biogas Production

Charcoal (biochar) is the raw material for the production of activated carbon. The production of activated charcoal itself goes through two main processes, namely carbonization (pyrolysis) and activation. The surface area of charcoal (biochar) is also smaller than that of activated carbon, but larger than the raw biomass. The carbonization process increases the surface area of the raw biomass. The ratio of surface area between raw biomass, charcoal and activated charcoal is approximately 25 m2 / gram, 200 m2 / gram, 2000 m2 / gram. The larger the surface area of the biomass material that is inserted into the biogas reactor, the greater the penetration of bacteria into the substrate so that the fermentation process that occurs is more perfect so that biogas production will increase. Biochar itself does not participate in fermentation because the main component is stable carbon, while hemicellulose, cellulose and lignin have been decomposed during the carbonization process.

Another example is the addition of biomass briquettes to the biogas reactor, briquetting processs with high pressure and heat also open pores or expand the surface of the biomass, so that biogas production also increases, for more details, read here. The addition of biomass briquettes to the biogas reactor will also increase the C / N ratio, even biochar and activated charcoal have high carbon (C) content.

Charcoal (biochar) has been widely used in the agricultural world to repair damaged soil / soil amendment and thus increase fertility. Good soil fertility will also increase agricultural production. The biochar becomes a home for soil microbes, so that organic materials or compost will break down more completely and be absorbed by plants more as plant nutrients. The charcoal (biochar) pores are the home for these microbes. The more pores, the more microbes will inhabit the biochar as their “house”. The same principle applies to the biogas unit. Another bonus of using biochar is that it absorbs CO2 from the atmosphere, thereby contributing to lowering the greenhouse gases that cause climate change and global warming.

Research in Germany shows that adding 5% biochar to a biogas reactor increases methane production by 5% - based on the dry matter of biochar to the substrate. But when the amount of biochar became 10%, it turned out that no more methane was added. This shows that the optimum condition for adding biochar is the amount of 5%. The microbes in the biochar increase the volume of microbes in the reactor so that the production of biogas or especially methane also increases up to 5%. Biochar itself is not decomposed in the fermentation process. 

Meanwhile, the addition of biomass briquettes per 1 tonne of briquettes will increase biogas production by 400 Nm3. This is because in the biomass briquettes, both cellulose, hemicellulose and lignin have not been decomposed, thus adding to the substrate in the biogas reactor. Whereas in biochar, both cellulose, hemicellulose and lignin have been decomposed during the thermal carbonization process, so there is practically no additional substrate, but only microbial addition occurs in the biochar pores.

The important thing about the addition of biochar is that the compost or digestate produced is of better quality with the addition of the biochar. Biochar will make the compost which is produced as a slow release organic fertilizer. This further encourages biochar production, especially for palm oil companies that care about environmental issues and even strive for zero waste conditions.

 Palm oil mills have the potential to apply biogas and biochar units. Solid wastes such as empty bunches and mesocarp fiber can be used for biochar production. Palm oil mills can even replace the furnace in the boiler with a gasifier or pyrolyser. This becomes more profitable because in addition to heat energy being used for production of steam which is used for power generation and sterilization of fresh fruit, biochar will also be produced. The biochar produced is then used to increase biogas production and improve the quality of the compost, as well as a fertilizer mixture in palm oil plantations. And even the potential use of biochar to save fertilizer on large palm oil plantations, for more details can be read here.     

Modernization Charcoal Production with Continuous Pyrolysis

Charcoal production and charcoal marketing have not been treated by strict rules such as wood pellets. This is mainly due to the large number of charcoal producers, with a small average production and traditional production technology. In addition, the market or buyer also does not require large volumes and long-term contracts. The quality factor remains an important standard, especially for the export market. But it could be that more stringent rules will also apply to production and marketing, given the potential damage caused. The low conversion of traditional charcoal kiln, which is an average of 15%, makes the need for wood raw materials extra, so that to produce 1 million tons of raw materials is needed about 6.5 million tons of wood. The approach to using efficient technology is increasingly urgent especially to serve large and continuous needs. Pyrolysis or continuous carbonization is the solution to this, with a conversion rate to charcoal reaching 30% or almost one third. With this efficient technology, only 3 million tons of wood is needed, or only half that means saving about 3 million tons of wood raw material.

Another motivation for using continuous pyrolysis technology is the high efficiency of energy savings that can be obtained. In charcoal production traditionally more than 60% of energy is lost during the production process. This can be illustrated in making charcoal from coconut shells. Conversion from raw materials to charcoal is only 15-25% in the process of traditional carbonization / pyrolysis. For example, we take a conversion of 25% (the best estimate), with a raw material of 10 tons of coconut shell, then 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 a lot of energy waste.

Whereas in the continuous pyrolysis process almost all energy can be utilized. Syngas and biooil are two types of by-products from pyrolysis that can be used as energy sources. Based on this, not only is conversion increasing, resulting in a reduction in raw materials which are also used by side products that can be used as energy sources. At present there are very few people who are thinking of utilizing the energy lost during the carbonization / pyrolysis process, this is because most people only think about how to increase the conversion to the charcoal. The loss of energy during the carbonization process is unknown or not realized by mostly charcoal producers in particular.

The use of 'lost energy' when the carbonization / pyrolysis process becomes another form of energy is certainly very good and adds value to its benefits. Electricity and heat are the two most needed forms of energy, so the conversion of 'lost energy' or pyrolysis / carbonization byproducts to become electric and heat energy is the best use scenario today. A number of regions or regions in the world still have low levels of electricity access. Africa, for example, on average has a low level of access to electricity, which is less than 30%, whereas in this region is the largest charcoal producer in the world which reaches 50% of global global production. By using continuous pyrolysis, this area, in addition to being the largest charcoal producer and even with a higher conversion, will also have access to electricity with the construction of a power plant fueled by the pyrolysis / carbonization by-products.

Charcoal is an energy product from biomass processing, especially wood. Wood charcoal has been known for a long time and is produced in a number of places. The process of producing wood charcoal is generally traditional, takes a long time and the quality is not uniform. According to FAO, global wood charcoal production in 2015 was recorded at more than 50 million tons and about half of it was produced in Africa. That means with the assumption that the conversion rate of 15% requires biomass, especially wood as raw material, as much as 333 million tons every year with 167 million tons coming from Africa. If the conversion rate to charcoal can be increased to 30% or two times, then the need for raw materials will decrease drastically or only half, namely 167 million tons globally and 83.5 million tons from Africa. What a very significant savings effort.

Every year Europe imports 1 million tons of charcoal, as well as Saudi Arabia and Middle Eastern countries import more than 1 million tons of charcoal. Saudi Arabia and the Middle East mainly use charcoal to roast lamb, a favorite food there. The use of charcoal in general is mostly the household sector with retail distribution. In addition charcoal is also used for metallurgy, agriculture (biochar) and activated charcoal (activated carbon) raw materials.

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.

Syngas Cleaning And Operation Time For Private/Independent Power Providers (IPP)

The continuity and stability of the electricity supply to the buyer is the most important thing for the private power provider or the Independent Power Producer (IPP). Electrical buyers in general are government through PLN or industry. To be able to provide such a continuous and stable electricity supply, IPP strives in such a way in a variety of ways including its various process engineering and also the operational. Biomass is a renewable energy source for electricity production that has many advantages especially in Indonesia, for example when wind and water (hydro) power plants are severely affected by weather conditions, the biomass power plant is not affected. Even high rainfall and tropical climate will increase the production of biomass as a source of energy. Related to the use of gas from biomass there are two routes to produce gas that is biology route and thermochemical route. The biological route is by fermentation in the digester, while the thermal route with gasification and pyrolysis. The characteristics of the raw material will determine the choice of technology, whether by biological route or thermochemical. Liquid waste or high water content and easy rot, such as livestock manure and palm oil mill effluent (POME) will use biological route, whereas biomass which is not easy to decompose such as woody biomass thermochemical route becomes the choice.

Why need to extract gas from the biomass? This is in addition to improving efficiency, also facilitate the utilization. Even by extracting the gas will also produce a number of economic value-added byproducts, for example with pyrolysis technology in addition to generating electricity, by-products such as charcoal, biooil, and biomass vinegar (liquid smoke). The economic value of these byproducts are bigger than the electricity production. The gas composition of the various biomasses also varies, depending on the biomass and the technology used, for example in biogas of large methane gas composition (55-75%), gasification of methane gas composition 0.5-3% while in pyrolysis gas composition methane 4-11%. Gas engine is a equipment or device commonly used to convert the combustible gas into electricity. Gas turbine although efficiency is higher but rarely used because of operational and maintenance factors are more difficult. Steam turbine is also rarely used and commonly used in large capacity power plants (> 20 MW). While Stirling engine and ORC (Organic Rankine Cycle) technology can also use gas from the biomass, but it is not specific because both Stirling engine and ORC only require heat for its operation and it does not have to be from gas. Practically both technologies above are using a lot of combustion to obtain the required heat.

Stirling Engine

ORC Technology

Gas Turbine

Gas Engine

The problem of purity or cleanliness of the gas that resulted in the operation of private power plants (IPP) received serious attention. The cleaner the gas and the stable the gas supply so the more stable the operation of the power plant and the opposite. The purchaser or user of electricity also requires the amount of electricity supply and tolerance to the breaking or shutting down of electricity at a certain time which must be fulfilled by the provider or private power producer. Various gas cleaning technologies have been used to obtain clean and stable gas supply to the converting equipments used. Gas cleaning technology in addition must be cheap and also easy to use so that electricity providers remain profitable. In general, the gas cleaning technology is to clean the gas from its impurities including also reduce or eliminate the gases that potentially disrupt the operation of such conversion equipments. For example CO2 and H2S gases in biogas process or tar in gasification and pyrolysis. 

Water scrubber (absorber) and stripper unit for biogas refinery

JF BioCarbon continuous pyrolysis technology is the best choice of electricity production from biomass with thermal route. This is in addition to generated electricity, also produced side products that are not less profitable, namely charcoal, biooil, and biomass vinegar. Then how about cleaning the gas so that the power supply electricity continuously? With a number of line cleaning units that work alternately, the continuity of the supply of clean gas can continue to run so also with the supply of electricity. A number of sensors are installed to ensure the cleanliness of the gas. Downtime or power outages will be reduced or even eliminated. Sufficient gas cleaning will ensure the continuous operation of the gas engine generator as a conversion unit from pyrolysis gas (chemical energy) to heat and mechanical energy (reciprocating engine in gas engine) and generate electricity. It is time for private power companies (IPP) to consider slowpyrolysis technology to continue as a wise and best choice for the production of electricity from biomass and a number of byproducts that are very profitable.

Palm Kernel Shell Continuous Pyrolysis For Multipurpose Production

Production of palm kernel shells (PKS) which is palm oil mill waste in Indonesia approximately 9 million tons. Current utilization of 20% (1.8 million tons) for export, 15% (1.35 million tons) for internal use, 10% (0.9 million tons) for domestic (local) use, and the remaining 55% (4.95 million tons) yet used or become waste. Meanwhile, Indonesia's CPO production currently reaches 35.2 million tons, or 20% of FFB (Fresh Fruit Bunch), so the number of FFB (Fresh Fruit Bunch) produced in Indonesia currently ranges from 176 million tons. With an average productivity of 20 tons / hectare of FFB, so the FFB is generated from 8.8 million hectares. While the total area of ​​oil palm plantations in Indonesia is currently estimated to have almost 12 million hectares including unfruitful and unproductive age or need to be replanting. Another influential factor is the low level of productivity of oil palm plantations. Palm kernel shells are only about 6% of the FFB produced, and after is used for the internal CPO production process in the mill  with mesocarp, only about 4.5% of the palm kernel shell is the waste of the palm factory. From there it can also be calculated that every hectare of oil palm plantation will produce 1.2 tons or three quarters namely 0.9 tons of waste. With the current expansion of oil palm plantations up to 12 million hectares, the potential of palm kernel shells that become waste in the palm oil plant around 10.8 million tons or the amount of 10.8 million tons that can be used for export, fuel and production of various other products or external use.

Currently, there are a number of parties who have utilized the palm kernel shells for electricity production and boilers of some industries that are estimated to be less than 10% of the total produced palm shells. Some converting technologies into heat and electricity are used for processing such palm kernel shells. Combustion and gasification are technologies commonly used to convert or extract palm kernel shells into heat and electricity. Combustion technology in the furnace then combined ORC (Organic Rankine Cycle) and Stirling engine to convert it into electricity. While the gas from gasification is then used as fuel in gas engine to generate electricity. Are there any other options for processing the palm kernel shell so that it has bigger added value or more profitable?

Palm kernel shells are not suitable for biogas production because the lignoselulose material or rich lignin content material making it difficult to biologically decompose. The choice is pyrolysis or thermal decomposition with absence of oxygen. Pyrolysis is a technology that can to produce charcoal, biooil, pyro acid and syngas. This is what makes it possible for multipurpose production. Palm kernel shells such as rice husks, sawdust and the like are bulk materials also so will be suitable for continuous pyrolysis. How come? The answer is because there are several options for using the continuous pyrolysis:

1. Production of electricity and charcoal 

2. Production of electricity and activated charcoal

3. Production of electricity and charcoal briquettes

4. Production of charcoal and bio-chemicals

5. Production of charcoal and biofuel

6. Production of Charcoal and heat

At the production of electricity and charcoal, the process of excess syngas is used for electricity production, and charcoal is also produced as a solid product of pyrolysis. The charcoal can also be made briquette so it will be efficient during transportation and its use. As for the production of electricity and activated carbon, then excess syngas is used for the process of activation of the charcoal produced, with a more detailed explanation can be read here. In addition to charcoal, bio-chemicals such as acetic acid, methanol and phenol can also be produced by processing further byproducts namely pyro acid and syngas. Biofuels namely, biooil and syngas can also be additional products besides charcoal. Syngas can also be packed in a tube for ease of distribution and usage. Meanwhile, if syngas and biooil are burned it will generate heat, so if the business of charcoal production in combination with agriculture such as the use of green house or also farms that require a warm certain temperature the continuous pyrolysis unit becomes also very effective to be used. 

Charcoal production from palm kernel shells can also be a solution to the high export tax of palm kernel shells. By processing it into finished product then the tax should be decreased even eliminated because there has been industrialization which also absorb labor and encourage economic growth. In private power producers or IPP (Independent Power Producer), the additional product namely of charcoal will provide an increase business revenue, so that their business becomes more attractive business. In addition to charcoal production, if you want the production of high quality solid fuel (solid biomass fuel) namely by upgrading or processing it with torrefaction, can be done also with pyrolysis technology.