Matthew Stone, Renovare Fuels: Next Generation Renewables

Renewable fuels are playing an ever-increasing role in the UK transport industry. Driven by the UK Government’s efforts to reduce Greenhouse Gas (GHG) emissions, the Renewable Transport Fuel Obligation (RTFO) stipulates that, from January 2021, fuel suppliers will be required to increase the proportion of renewables within their total sales.

Led by a management team of experienced professionals that includes Business Development Director Duncan Clark, Renovare Fuels could play a pivotal role in helping UK fuel companies meet the strict new criteria being imposed.

renewable-diesel

Biofuels are increasingly being used to power vehicles around the world

The UK transport industry generated 28% of total UK pollution in 2019, making it the country’s most polluting sector. The robust RTFO scheme was implemented to drive sustainability in the industry through the reduction of GHG emissions.

Under the scheme, transport fuel providers who provide more than 450,000 litres of petrol, gas oil or diesel must incorporate a prescribed amount of renewable fuels within their overall fuel sales, or forfeit a per-litre penalty.

Under the terms of the RTFO, the amount of renewables fuel suppliers must include in their products rises every year. The strategy forms an integral part of UK Government efforts to reduce the amount of carbon produced by the transport sector – a vital element of bringing total GHG emissions to net zero by 2050. Fuel suppliers will be required to increase development of renewable fuel components to at least 10.68% of their total supply levels in 2021.

Introduced in the 1980s, standard renewables like biodiesel and bioethanol produce similar levels of carbon dioxide emissions to fossil fuels when they are burned. However, rather than being produced from finite resources, they are derived from biomass feedstocks. These are typically grown specifically for the production of fuel or produced using waste products from other industries, such as agriculture and food. Although biomass produces CO2 when burned, this is offset by carbon dioxide absorbed by feedstock during the production process, effectively creating a closed loop process.

biofuel-powered-vehicle

Lower GHG emissions and empowerment of rural economy are major benefits associated with bioethanol

In 2019, advanced development fuels were added to the terms of the RTFO, enabling fuel companies to integrate next generation biofuels into market supplies in addition to standard renewables.

With the exception of segregated fats and oils and renewable fuels of non-biological origin (RFNBOs), development fuels are synthesised from residual feedstock or sustainable waste. To qualify under the scheme, a development fuel must have a GHG saving of at least 60% more than that offset by fossil fuels. Renewable diesel must be blendable at a rate of at least 25% with conventional diesel, while still meeting the EN590 fuel specification. Fuels which possess these superior carbon neutrality credentials are eligible for double the amount of Renewable Transport Fuel Certificates per kilo or litre compared with standard renewable fuels.

As Matthew Stone – Renovare Fuels’ Chairman – explains, development biofuels overcome many limitations associated with first-generation biofuels. From a physical and chemical perspective, Renovare Fuels’ next generation biofuels are closer to conventional fossil fuels, particularly in terms of performance and end product quality, while producing just three grams of CO2 per megajoule of biomass – which is just 3% of that generated by fossil fuels.

Standard biofuels have a limited impact in reducing GHG emissions, chiefly due to the type of feedstock used and low fuel quality. In contrast, development fuels are much more efficient, since they are specifically designed to eliminate emissions throughout the production process, as well as radically reducing those produced when used as an end fuel. As Matthew Stone points out, next generation development fuels show vast potential, supporting the UK Government’s GHG reduction goals.

Biofuels from Syngas

An attractive approach to converting biomass into liquid or gaseous fuels is direct gasification, followed by conversion of the syngas to final fuel. Ethanol can be produced this way, but other fuels can be produced more easily and potentially at lower cost, though none of the approaches is currently inexpensive.

The choice of which process to use is influenced by the fact that lignin cannot easily be converted into a gas through biochemical conversion. Lignin can, however, be gasified through a heat process. The lignin components of plants can range from near 0% to 35%. For those plants at the lower end of this range, the chemical conversion approach is better suited. For plants that have more lignin, the heat-dominated approach is more effective.

Gasification_Process

Layout of a Typical Biomass Gasification Plant

Once the gasification of biomass is complete, the resulting syngas or synthetic gas can be used in a variety of ways to produce liquid fuels as mentioned below

Fischer-Tropsch (F-T) fuels

The Fischer-Tropsch process converts “syngas” (mainly carbon monoxide and hydrogen) into diesel fuel and naphtha (basic gasoline) by building polymer chains out of these basic building blocks. Typically a variety of co-products (various chemicals) are also produced.

The Fisher-Tropsch process is an established technology and has been proven on a large scale but adoption has been limited by high capital and O&M costs. According to Choren Industries, a German based developer of the technology, it takes 5 tons of biomass to produce 1 ton of biodiesel, and 1 hectare generates 4 tons of biodiesel.

Methanol

Syngas can also be converted into methanol through dehydration or other techniques, and in fact methanol is an intermediate product of the F-T process (and is therefore cheaper to produce than F-T gasoline and diesel).

Methanol is somewhat out of favour as a transportation fuel due to its relatively low energy content and high toxicity, but might be a preferred fuel if fuel cell vehicles are developed with on-board reforming of hydrogen.

Dimethyl ether

DME also can be produced from syngas, in a manner similar to methanol. It is a promising fuel for diesel engines, due to its good combustion and emissions properties. However, like LPG, it requires special fuel handling and storage equipment and some modifications of diesel engines, and is still at an experimental phase.

If diesel vehicles were designed and produced to run on DME, they would become inherently very low pollutant emitting vehicles; with DME produced from biomass, they would also become very low GHG vehicles.

Torrified PKS: An Attractive Biomass Commodity in West Africa

Even though palm kernel shell has many similarities with wood pellets, it is not easy to reduce its size which makes it difficult for its optimum cofiring with coal in power plants and industries. Few years ago, Indonesia had exported PKS to Poland for cofiring purposes but because PKS was difficult to make powder (low grindability) it made cofiring performance poor, so the use of PKS for cofiring is currently discontinued.

palm-kernel-shells

 

To improve the quality of PKS, especially for the use of cofiring, PKS must be processed with torrefaction (mild pyrolysis). With the torrefaction process, it becomes easier to make powder from PKS, so that the desired particle size for cofiring is easier to obtain. Another advantage of the torrefaction process is that the caloric value of PKS will also increase by about 20%, Torrified biomass is hygroscopic which means ease in indoor as well as outdoor storage.

During the torrefaction process, PKS is heated at a temperature of around 230 to 300 °C in the absence of oxygen. With continuous pyrolysis technology, torrified PKS production can be carried out at large capacities. The need for biomass fuel for electricity generation is also large, usually requiring 10 thousand tons for each shipment. PKS torrified producers must be able to reach this capacity. The production of 10 thousand tons of PKS that are burned can be done per month or several months, for example, to reach 10 thousand tons it takes 2 months because the factory capacity is 5000 tons per month.

PKS-torrefaction

In general, the advantages of the PKS torrefaction process are as follows:

  • It increases the O/C ratio of the biomass, which improves its thermal process
  • It reduces power requirements for size reduction, and improves handling.
  • It offers cleaner-burning fuel with little acid in the smoke.
  • Torrefied PKS absorbs less moisture when stored.
  • One can produce superior-quality PKS pellets with higher volumetric energy density.

Pelletizing of torrefied PKS can be an option to increase the energy density in volume basis. The pelletizing process resolves some typical problems of biomass fuels: transport and storing costs are minimized, handling is improved, and the volumetric calorific value is increased. Pelletization may not increase the energy density on a mass basis, but it can increase the energy content of the fuel on a volume basis.

Africa, especially West Africa, which has many palm oil plantations and also the location where the palm oil trees originate, can supply torrified PKS to Europe to meet its rapidly-increasing biomass fuel demand.

In Africa, palm kernel shell is generally produced from PKO mills. CPO production is generally carried out on a small scale and only processes the fiber portion of the palm oil fruit. This palm oil mesocarp fibre is processed to produce CPO, while the nut that consist kernels and shells are processed elsewhere to produce the main product of PKO (palm kernel oil). PKO mills are usually quite large by collecting nuts from these small scale CPO producers. PKS is produced from this PKO mills.

nut-cracker-machine-palm-mill

The nut cracker machine separates kernel and shell

The distance between Africa and Europe is also closer than Europe to Malaysia and Indonesia. Currently, even though Europe has produced wood pellets for their renewable energy program to mitigate climate change and the environment, the numbers are still insufficient and they are importing wood pellets from the United States and Canada in large quantities. European wood pellet imports are estimated to reach more than 1.5 million tons per year. Torrified PKS from West Africa can help in meeting the biomass fuel demands for power plants across Europe.

For more information about PKS trading opportunities and our technical consulting services, please email on salman@bioenergyconsult.com or eko.sb.setyawan@gmail.com

Energy Potential of Bagasse

Sugarcane is one of the most promising agricultural sources of biomass energy in the world. Sugarcane produces mainly two types of biomass – sugarcane trash and bagasse. Sugarcane trash is the field residue remaining after harvesting the sugarcane stalk while bagasse is the fibrous residue left over after milling of the sugarcane, with 45-50% moisture content and consisting of a mixture of hard fibre, with soft and smooth parenchymatous (pith) tissue with high hygroscopic property.

Bagasse contains mainly cellulose, hemicellulose, pentosans, lignin, sugars, wax, and minerals. The quantity obtained varies from 22 to 36% on sugarcane and is mainly due to the fibre portion in the sugarcane and the cleanliness of sugarcane supplied, which, in turn, depends on harvesting practices.

The composition of bagasse depends on the variety and maturity of sugarcane as well as harvesting methods applied and efficiency of the sugar processing. Bagasse is usually combusted in furnaces to produce steam for power generation. Bagasse is also emerging as an attractive feedstock for bioethanol production.

It is also utilized as the raw material for production of paper and as feedstock for cattle. The value of Bagasse as a fuel depends largely on its calorific value, which in turn is affected by its composition, especially with respect to its water content and to the calorific value of the sugarcane crop, which depends mainly on its sucrose content.

Moisture contents is the main determinant of calorific value i.e. the lower the moisture content, the higher the calorific value. A good milling process will result in low moisture of 45% whereas 52% moisture would indicate poor milling efficiency. Most mills produce Bagasse of 48% moisture content, and most boilers are designed to burn Bagasse at around 50% moisture.

Bagasse also contains approximately equal proportion of fibre (cellulose), the components of which are carbon, hydrogen and oxygen, some sucrose (1-2 %), and ash originating from extraneous matter. Extraneous matter content is higher with mechanical harvesting and subsequently results in lower calorific value.

For every 100 tons of Sugarcane crushed, a Sugar factory produces nearly 30 tons of wet Bagasse. Bagasse is often used as a primary fuel source for Sugar mills; when burned in quantity, it produces sufficient heat and electrical energy to supply all the needs of a typical Sugar mill, with energy to spare. The resulting CO2 emissions are equal to the amount of CO2 that the Sugarcane plant absorbed from the atmosphere during its growing phase, which makes the process of cogeneration greenhouse gas-neutral.

35MW Bagasse and Coal CHP Plant in Mauritius

Cogeneration of bagasse is one of the most attractive and successful biomass energy projects that have already been demonstrated in many sugarcane producing countries such as Mauritius, Reunion Island, India and Brazil. Combined heat and power from sugarcane in the form of power generation offers renewable energy options that promote sustainable development, take advantage of domestic resources, increase profitability and competitiveness in the industry, and cost-effectively address climate mitigation and other environmental goals.

Torrefaction of Biomass: An Overview

To improve the quality of biomass, especially for cofiring purposes, biomass waste can be processed with torrefaction (also known as mild pyrolysis). With the torrefaction process, it becomes easier to make powder (high grindability) so that the desired particle size for cofiring of biomass is easier to obtain. Another advantage of the torrefaction process is that the caloric value of biomass increases by about 20%. Torrified biomass is essentially hydropobic which means ease in storage including outdoor storage. This condition also makes it easier to handle and use, in addition to reduction in transportation costs.

torrefaction-of-biomass

What is Torrefaction

Torrefaction, which is currently being considered for effective biomass utilization, is also a form of pyrolysis. In this process (named for the French word for roasting), the biomass is heated to 230 to 300 °C without contact with oxygen. For comparison, pyrolysis of biomass is typically carried out in a relatively low temperature range of 300 to 650 °C compared to 800 to 1000 °C for gasification. Torrefaction is a relatively new process that heats the biomass in the absence of air to improve its usefulness as a fuel.

Torrefaction, a process different from carbonization, is a mild pyrolysis process carried out in a temperature range of 230 to 300 °C in the absence of oxygen. During this process the biomass dries and partially devolatilizes, decreasing its mass while largely preserving its energy content. The torrefaction process removes H2O and CO2 from the biomass. As a result, both the O/C and the H/C ratios of the biomass decrease.

steps-in-biomass-torrefaction

Advantages of Biomass Torrefaction

Torrefaction of biomass improves its energy density, reduces its oxygen-to-carbon (O/C) ratio, and reduces its hygroscopic nature. Torrefaction also increases the relative carbon content of the biomass. The properties of a torrefied biomass depends on torrefaction temperature, time, and on the type of biomass feed.

Torrefaction also modifies the structure of the biomass, making it more friable or brittle. This is caused by the depolymerization of hemicellulose. As a result, the process of size reduction becomes easier, lowering its energy consumption and the cost of handling. This makes it easier to cofire biomass in a pulverized coal-fired boiler or gasify it in an entrained-flow reactor.

Another special feature of torrefaction is that it reduces the hygroscopic property of biomass; therefore, when torrefied biomass is stored, it absorbs less moisture than that absorbed by fresh biomass. For example, while raw bagasse absorbed 186% moisture when immersed in water for two hours, it absorbed only 7.6% moisture under this condition after torrefying the bagasse for 60 minutes at 250 °C (Pimchua et al., 2009). The reduced hygroscopic (or enhanced hydrophobic) nature of torrefied biomass mitigates one of the major shortcomings for energy use of biomass.

In biomass, hemicellulose is like the cement in reinforced concrete, and cellulose is like the steel rods. The strands of microfibrils (cellulose) are supported by the hemicellulose. Decomposition of hemicellulose during torrefaction is like the melting away of the cement from the reinforced concrete. Thus, the size reduction of biomass consumes less energy after torrefaction. During torrefaction the weight loss of biomass comes primarily from the decomposition of its hemicellulose constituents. Hemicellulose decomposes mostly within the temperature range 150 to 280 °C, which is the temperature window of torrefaction.

torrified-biomass

As we can see from figure above, the hemicellulose component undergoes the greatest amount of degradation within the 200 to 300 °C temperature window. Thus, hemicellulose decomposition is the primary mechanism of torrefaction. At lower temperatures (< 160 °C), as biomass dries it releases H2O and CO2. Water and carbon dioxide, which make no contribution to the energy in the product gas, constitute a dominant portion of the weight loss during torrefaction.

Above 180 °C, the reaction becomes exothermic, releasing gas with small heating values. The initial stage (< 250 °C) involves hemicellulose depolymerization, leading to an altered and rearranged polysugar structures. At higher temperatures (250–300 °C) these form chars, CO, CO2, and H2O. The hygroscopic property of biomass is partly lost in torrefaction because of the destruction of OH groups through dehydration, which prevents the formation of hydrogen bonds.

Biorefinery Prospects in India

India has a tremendous biomass potential which could easily be relied upon to fulfil most of our energy needs. An estimated 50 MMT (million metric tonnes) of liquid fuels are consumed annually in India, but with the actual biomass potential and its full utilization, India is capable of generating almost double that amount per annum. These biomass estimates only constitute the crop residues available in the country and essentially the second-generation fuels since the use of first-generation crop bases fuels in such food-starved nations is a criminal thought.

Biomass-India

Existing Technologies

Currently, there are various technologies available to process such crop residues and generate value products from them. However, essentially, they all revolve around two main kinds of processes, either biochemical or thermal.

The biochemical process involves application of aerobic/anaerobic digestion for the production of biogas; or fermentation, which results in the generation of ethanol. Both these products could be subsequently treated chemically and through trans-esterification process, leading to production of biodiesel.

Alternatively, the thermochemical processes involve either the combustion, gasification or pyrolysis techniques, which produces heat, energy-rich gas and liquid fuels respectively. These products can be used as such, or could be further processed to generate high quality biofuels or chemicals.

The Need

The estimated organized energy breakup for India is 40 percent each for domestic and transport sectors and 20 percent for the industrial sectors. The current share of crude oil and gases is nearly 90 percent for the primary and transport sectors and the remaining 10 percent for the generation of industrial chemicals.

The fluctuating prices of crude oil in the international market and the resulting concern over energy security, has lead developing nations to explore alternative and cheap sources of energy to meet the growing energy demand. One of the promising solution for agrarian economies is Biorefinery.

The Concept

Biorefinery is analogous to the traditional petroleum refineries employing fractional distillation process for obtaining different fractions or components from the same raw material, i.e. the crude oil. Biorefinery involve the integration of different biomass treatment and processing methods into one system, which results in the production of different components from the same biomass.  This makes the entire chain more viable economically and also reduces the waste generated.

Typical Model of a Biorefinery

The outcome ranges from high-volume, low-energy content liquid fuels, which could serve the transportation industry needs, to the low-volume but high-value chemicals, which could add to the feasibility of such a project.

Steam and heat generated in the process could be utilized for meeting process heat requirements. By-products like chemicals, fertilizers, pharmaceuticals, polymers etc are also obtained which provide additional revenue streams.

Benefits

Biorefineries can help in utilizing the optimum energy potential of organic wastes and may also resolve the problems of waste management and GHGs emissions. Wastes can be converted, through appropriate enzymatic/chemical treatment, into either gaseous or liquid fuels.

The pre-treatment processes involved in biorefining generate products like paper-pulp, HFCS, solvents, acetate, resins, laminates, adhesives, flavour chemicals, activated carbon, fuel enhancers, undigested sugars etc. which generally remain untapped in the traditional processes. The suitability of this process is further enhanced from the fact that it can utilize a variety of biomass resources, whether plant-derived or animal-derived.

Applicability

The concept of biorefinery is still in early stages at most places in the world. Problems like raw material availability, feasibility in product supply chain, scalability of the model are hampering its development at commercial-scales. The National Renewable Energy Laboratory (NREL) of USA is leading the front in biorefinery research with path-breaking discoveries and inventions.

Although the technology is still in nascent stages, but it holds the key to the optimum utilization of wastes and natural resources that humans have always tried to achieve. The onus now lies on governments and corporate to incentivize or finance the research and development in this field.

Prospects of Algae Biofuels in Middle East

Algae biofuels have the potential to become a renewable, cost-effective alternative for fossil fuels with reduced impact on the environment. Algae hold tremendous potential to provide a non-food, high-yield, non-arable land use source of renewable fuels like biodiesel, bioethanol, hydrogen etc. Microalgae are considered as a potential oleo-feedstock, as they produce lipids through photosynthesis, i.e. using only CO2, water, sunlight, phosphates, nitrates and other (oligo) elements that can be found in residual waters.

algae-middle-east

Algae also produce proteins, isoprenoids and polysaccharides. Some strains of algae ferment sugars to produce alcohols, under the right growing conditions. Their biomass can be processed to different sorts of chemicals and polymers (Polysaccharides, enzymes, pigments and minerals), biofuels (e.g. biodiesel, alkanes and alcohols), food and animal feed (PUFA, vitamins, etc.) as well as bioactive compounds (antibiotics, antioxidant and metabolites) through down-processing technology such as transesterification, pyrolysis and continuous catalysis using microspheres.

Microalgae are the fastest growing photosynthesizing organism capable of completing an entire growing cycle every few days. Up to 50% of algae’s weight is comprised of oil, compared with, for example, oil palm which yields just about 20% of its weight in oil. Algae can be grown on non-arable land (including deserts), most of them do not require fresh water, and their nutritional value is high. Extensive R&D efforts are underway worldwide, especially in North America and Europe, with a high number of start-up companies developing different options for commercializing algae farming.

Prospects of Algae Biofuels in the Middle East

The demand for fossil fuels is growing continuously all around the world and the Middle East is not an exception. The domestic consumption of energy in the Middle East is increasing at an astonishing rate, e.g. Saudi Arabia’s consumption of oil and gas rose by about 5.9 percent over the past five years while electricity demand is witnessing annual growth rate of 8 percent. Although Middle Eastern countries are world’s leading producers of fossil fuels, several cleantech initiatives have been launched in last few years which shows the commitment of regional countries in exploiting renewable sources of energy.

Algae biofuels is an attractive proposition for Middle East countries to offset the environmental impact of the oil and gas industry. The region is highly suitable for mass production of algae because of the following reasons:

  • Presence of large tracts of non-arable lands and extensive coastline.
  • Presence of numerous oil refineries and power plants (as points of CO2 capture) and desalination plants (for salt reuse).
  • Extremely favorable climatic conditions (highest annual solar irradiance).
  • Presence of a large number of sewage and wastewater treatment plants.
  • Existence of highly lipid productive microalgae species in coastal waters.

These factors makes it imperative on Middle East nations to develop a robust Research, Development and Market Deployment plan for a comprehensive microalgal biomass-based biorefinery approach for bio-product synthesis. An integrated and gradual appreciation of technical, economic, social and environmental issues should be considered for a successful implementation of the microalgae-based oleo-feedstock (MBOFs) industry in the region.

How the Biofuel Industry is Growing in the US

Biofuels were once forgotten in the United States, mainly when huge petroleum deposits kept fuel prices low.  With the increase in oil prices recently, the biofuel industry in the US is rising significantly.  Experts predict that this green energy efficient industry will continue to grow within the next 7 to 10 years.

drop-in-biofuels

The Source of Biofuels

Those who are concerned with the prospect of global warming love the potential use of biofuels. Produced either directly or indirectly from used cooking oil, animal waste and plant materials, biofuels are less costly than other types of fuel.  Already in the national and global market, the trend for this fuel is rising.

Online Reverse Auction Software

Due to the growth of the biofuel industry, online software for energy brokers and energy suppliers is an available market for entrepreneurs.  The software to efficiently sell energy services to purchasers is a must have for suppliers and brokers.  The reverse auction process effectively conducts online business for those in the biofuel industry.

Both regulated and deregulated gas and electricity markets are involved in the reverse auction process in which the buyer and seller roles are reversed.  The buyer is given the option of testing and evaluating multiple pricing parameters to find a good fit.  Commercial, industrial, and manufacturing facilities take advantage of this platform.

Reverse Auction Benefits

Reverse auctions in the biofuel industry have been said to cut costs tremendously.  Although the seller pays a fee to the service provider, the bidding process cuts costs all around for both buyer and seller.  A situation in which both sides win is seen as a huge benefit by all involved.

As a very lucrative market, the biofuel industry benefits from reverse auctions.  Market efficiency is increased, and the process of obtaining the goods and services is enhanced.  Proper software and other technical aspects of the process is essential thus the reason that the online reverse auction software market is critical.  Quality and professional relationships are enhanced rather than compromised as is often the case in other markets.

Biofuel Market Projections and Uses

According to market research, the biofuel industry is expected to reach approximately 218 billion dollars by 2022.  A 4.5% growth is expected by 2022 as well.  Investors see these projections as an open door of opportunity.  By the year 2025, the increase is predicted to be at approximately 240 billion dollars.

Biofuel is used for other purposes besides first-generation fuel.  It is used in vegetable oil and cosmetics, and it is used to treat Vitamin A deficiency and other health issues. Biofuel is predicted to aid the improvement of economic conditions due to its health benefits and appeal to green energy supporters.  These factors explain the reasons for the projected growth and profit for this industry.

With the continued growth of the biofuel industry, reverse auctions will be a much-needed process.  The efficient software to accompany reverse auctions will keep the market flowing which will further aid the growth of the industry for years to come.

Charcoal Briquette Production in the Middle East: Perspectives

There is a huge demand for charcoal briquettes in the Middle East, especially in Saudi Arabia, Egypt and UAE. However the production of charcoal in the Middle East is in nascent stages despite the availability of biomass resources, especially date palm biomass. The key reason for increasing demand of charcoal briquettes is the large consumption of meat in the region which uses charcoal briquettes as fuel for barbecue, outdoor grills and related activities.

The raw materials for charcoal briquette production are widely available across the Middle East in the form of date palm biomass, crop wastes and woody biomass. With a population of date palm trees of 84 million or 70% of the world’s population, the potential biomass waste from date palm trees is estimated at 730,000 tons / year (approximately 200,000 tons from Saudi Arabia and 300,000 tons from Egypt). Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits.

The fronds and trunks of date palm trees are potential raw materials for charcoal because of the potential to produce high calorific value and low ash content charcoal. Leaf waste will produce a low calorific value due to high ash content. In addition, woody biomass waste such as cotton stalks that are widely available in Egypt can also be a raw material for making charcoal. The contribution of the agricultural sector in Egypt is quite high at 13.4%.

Charcoal is compacted into briquettes for ease in handling, packaging, transportation and use. Briquettes can be made in different shapes such as oval, hexagonal, cube, cylinder or octagonal. An adhesive (called binder) is needed for the manufacture of the briquette. Two common binders are saw dust and corn starch.

Date palm biomass is an excellent resource for charcoal production in Middle East

Continuous pyrolysis is the best technology for charcoal production. Continuous pyrolysis has the ability to handle large biomass volumes, the process is fast and smoke production is negligible. When using conventional pyrolysis technology  (or batch carbonization), the process is lengthy, processing capacity is small and there are concerns related to harmful smoke emissions.

Apart from charcoal, continuous pyrolysis also gives bio oil, wood vinegar and syngas. Syngas can be converted into electricity by using a gas engine or converted into a wide variety of biofuels through different processes. Bio oil can be used as boiler fuel and marine fuel. Wood vinegar can be used as biopesticide and liquid organic fertilizer. Low water content in date palm waste fronds and trunks make it very suitable for thermochemical conversion technologies, especially pyrolysis and gasification.

 

Charcoal can also be used for the production of activated charcoal/carbon. Activated carbon is used by a lot of industries for purification processes. In addition, a number of industries that are using petcoke as fuel can switch to charcoal due to its better combustion properties and eco-friendly nature.

For more information on how to set up charcoal production plant based on date palm biomass or other crop residues in the Middle East, please email salman@bioenergyconsult.com or eko.sb.setyawan@gmail.com

Overview of Biomass Pyrolysis Process

Biomass pyrolysis is the thermal decomposition of biomass occurring in the absence of oxygen. It is the fundamental chemical reaction that is the precursor of both the combustion and gasification processes and occurs naturally in the first two seconds. The products of biomass pyrolysis include biochar, bio-oil and gases including methane, hydrogen, carbon monoxide, and carbon dioxide.

The biomass pyrolysis process consists of both simultaneous and successive reactions when organic material is heated in a non-reactive atmosphere. Thermal decomposition of organic components in biomass starts at 350 °C–550 °C and goes up to 700 °C–800 °C in the absence of air/oxygen. The long chains of carbon, hydrogen and oxygen compounds in biomass break down into smaller molecules in the form of gases, condensable vapours (tars and oils) and solid charcoal under pyrolysis conditions. Rate and extent of decomposition of each of these components depends on the process parameters of the reactor temperature, biomass heating rate, pressure, reactor configuration, feedstock etc

Depending on the thermal environment and the final temperature, pyrolysis will yield mainly biochar at low temperatures, less than 450 0C, when the heating rate is quite slow, and mainly gases at high temperatures, greater than 800 0C, with rapid heating rates. At an intermediate temperature and under relatively high heating rates, the main product is bio-oil.

Slow and Fast Pyrolysis

Pyrolysis processes can be categorized as slow or fast. Slow pyrolysis takes several hours to complete and results in biochar as the main product. On the other hand, fast pyrolysis yields 60% bio-oil and takes seconds for complete pyrolysis. In addition, it gives 20% biochar and 20% syngas.  Fast pyrolysis is currently the most widely used pyrolysis system.

The essential features of a fast pyrolysis process are:

  • Very high heating and heat transfer rates, which require a finely ground feed.
  • Carefully controlled reaction temperature of around 500oC in the vapour phase
  •  Residence time of pyrolysis vapours in the reactor less than 1 sec
  • Quenching (rapid cooling) of the pyrolysis vapours to give the bio-oil product.

Advantages of Biomass Pyrolysis

Pyrolysis can be performed at relatively small scale and at remote locations which enhance energy density of the biomass resource and reduce transport and handling costs.  Heat transfer is a critical area in pyrolysis as the pyrolysis process is endothermic and sufficient heat transfer surface has to be provided to meet process heat needs. Biomass pyrolysis offers a flexible and attractive way of converting organic matter into energy products which can be successfully used for the production of heat, power and chemicals.

A wide range of biomass feedstock can be used in pyrolysis processes. The pyrolysis process is very dependent on the moisture content of the feedstock, which should be around 10%. At higher moisture contents, high levels of water are produced and at lower levels there is a risk that the process only produces dust instead of oil. High-moisture waste streams, such as sludge and meat processing wastes, require drying before subjecting to pyrolysis.

Furthermore, the bio-char produced can be used on the farm as an excellent soil amender as it is highly absorbent and therefore increases the soil’s ability to retain water, nutrients and agricultural chemicals, preventing water contamination and soil erosion. Soil application of bio-char may enhance both soil quality and be an effective means of sequestering large amounts of carbon, thereby helping to mitigate global climate change through carbon sequestration.  Use of bio-char as a soil amendment will offset many of the problems associated with removing crop residues from the land.

Biomass pyrolysis has been garnering much attention due to its high efficiency and good environmental performance characteristics. It also provides an opportunity for the processing of agricultural residues, wood wastes and municipal solid waste into clean energy. In addition, biochar sequestration could make a big difference in the fossil fuel emissions worldwide and act as a major player in the global carbon market with its robust, clean and simple production technology.