About Salman Zafar

Salman Zafar is the CEO of BioEnergy Consult, and an international consultant, advisor and trainer with expertise in waste management, biomass energy, waste-to-energy, environment protection and resource conservation. His geographical areas of focus include Asia, Africa and the Middle East. Salman has successfully accomplished a wide range of projects in the areas of biogas technology, biomass energy, waste-to-energy, recycling and waste management. Salman has participated in numerous national and international conferences all over the world. He is a prolific environmental journalist, and has authored more than 300 articles in reputed journals, magazines and websites. In addition, he is proactively engaged in creating mass awareness on renewable energy, waste management and environmental sustainability through his blogs and portals. Salman can be reached at salman@bioenergyconsult.com or salman@cleantechloops.com.

Biomass Energy in Vietnam

Vietnam is one of the few countries having a low level of energy consumption in the developing world with an estimated amount of 210 kg of oil equivalent per capita/year. Over half of the Vietnamese population does not have access to electricity. Vietnam is facing the difficult challenge of maintaining this growth in a sustainable manner, with no or minimal adverse impacts on society and the environment.

Being an agricultural country, Vietnam has very good biomass energy potential. Agricultural wastes are most abundant in the Mekong Delta region with approximately 50% of the amount of the whole country and Red River Delta with 15%. Major biomass resources includes rice husk from paddy milling stations, bagasse from sugar factories, coffee husk from coffee processing plants in the Central Highlands and wood chip from wood processing industries. Vietnam has set a target of having a combined capacity of 500 MW of biomass power by 2020, which is raised to 2,000 MW in 2030.

Rice husk and bagasse are the biomass resources with the greatest economic potential, estimated at 50 MW and 150 MW respectively. Biomass fuels sources that can also be developed include forest wood, rubber wood, logging residues, saw mill residues, sugar cane residues, bagasse, coffee husk and coconut residues. Currently biomass is generally treated as a non-commercial energy source, and collected and used locally. Nearly 40 bagasse-based biomass power plants have been developed with a total designed capacity of 150 MW but they are still unable to connect with the national grid due to current low power prices. Five cogeneration systems selling extra electricity to national grid at average price of 4UScents/kWh.

Biogas energy potential is approximately 10 billion m3/year, which can be collected from landfills, animal excrements, agricultural residues, industrial wastewater etc. The biogas potential in the country is large due to livestock population of more than 30 million, mostly pigs, cattle, and water buffalo. Although most livestock dung already is used in feeding fish and fertilizing fields and gardens, there is potential for higher-value utilization through biogas production. It is estimated that more than 25,000 household biogas digesters with 1 to 50 m3, have been installed in rural areas. The Dutch-funded Biogas Program operated by SNV Vietnam constructed some 18,000 biogas facilities in 12 provinces between 2003 and 2005, with a second phase (2007-2010) target of 150,000 biogas tanks in both rural and semi-urban settings.

Municipal solid waste is also a good biomass resource as the amount of solid waste generated in Vietnam has been increasing steadily over the last few decades. In 1996, the average amount of waste produced per year was 5.9 million tons per annum which rose to 28 million tons per in 2008 and expected to reach 44 million tons per year by 2015.

Overview of Biomass Energy Systems

Biomass is a versatile energy source that can be used for production of heat, power, transport fuels and biomaterials, apart from making a significant contribution to climate change mitigation. Currently, biomass-driven combined heat and power, co-firing, and combustion plants provide reliable, efficient, and clean power and heat. Feedstock for biomass energy plants can include residues from agriculture, forestry, wood processing, and food processing industries, municipal solid wastes, industrial wastes and biomass produced from degraded and marginal lands.

The terms biomass energy, bioenergy and biofuels cover any energy products derived from plant or animal or organic material. The increasing interest in biomass energy and biofuels has been the result of the following associated benefits:

  • Potential to reduce GHG emissions.
  • Energy security benefits.
  • Substitution for diminishing global oil supplies.
  • Potential impacts on waste management strategy.
  • Capacity to convert a wide variety of wastes into clean energy.
  • Technological advancement in thermal and biochemical processes for waste-to-energy transformation.

Biomass can play the pivotal role in production of carbon-neutral fuels of high quality as well as providing feedstocks for various industries. This is a unique property of biomass compared to other renewable energies and which makes biomass a prime alternative to the use of fossil fuels. Performance of biomass-based systems for heat and power generation has been already proved in many situations on commercial as well as domestic scales.

Biomass energy systems have the potential to address many environmental issues, especially global warming and greenhouse gases emissions, and foster sustainable development among poor communities. Biomass fuel sources are readily available in rural and urban areas of all countries. Biomass-based industries can provide appreciable employment opportunities and promote biomass re-growth through sustainable land management practices.

The negative aspects of traditional biomass utilization in developing countries can be mitigated by promotion of modern waste-to-energy technologies which provide solid, liquid and gaseous fuels as well as electricity as shown. Biomass wastes can be transformed into clean and efficient energy by biochemical as well as thermochemical technologies.

The most common technique for producing both heat and electrical energy from biomass wastes is direct combustion. Thermal efficiencies as high as 80 – 90% can be achieved by advanced gasification technology with greatly reduced atmospheric emissions. Combined heat and power (CHP) systems, ranging from small-scale technology to large grid-connected facilities, provide significantly higher efficiencies than systems that only generate electricity.  Biochemical processes, like anaerobic digestion and sanitary landfills, can also produce clean energy in the form of biogas and producer gas which can be converted to power and heat using a gas engine.

In addition, biomass wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels. Cellulosic ethanol can be produced from grasses, wood chips and agricultural residues by biochemical route using heat, pressure, chemicals and enzymes to unlock the sugars in cellulosic biomass. Algal biomass is also emerging as a good source of energy because it can serve as natural source of oil, which conventional refineries can transform into jet fuel or diesel fuel.

Biological Cleanup of Biogas

The most valuable component of biogas is methane (CH4) which typically makes up 60%, with the balance being carbon dioxide (CO2) and small percentages of other gases. However, biogas also contain significant amount of hydrogen sulfide (H2S) gas which needs to be stripped off due to its highly corrosive nature. Hydrogen sulfide is oxidized into sulfur dioxide which dissolves as sulfuric acid. Sulphuric acid, even in trace amounts, can make a solution extremely acidic. Extremely acidic electrolytes dissolve metals rapidly and speed up the corrosion process.

The corrosive nature of H2S has the potential to destroy expensive biogas processing equipment. Even if there is no oxygen present, biogas can corrode metal. Hydrogen sulphide can become its own electrolyte and absorb directly onto the metal to form corrosion. If the hydrogen sulphide concentration is very low, the corrosion will be slow but will still occur due to the presence of carbon dioxide.

The obvious solution is the use of a biogas cleanup process whereby contaminants in the raw biogas stream are absorbed or scrubbed. Desulphurization of biogas can be performed by biological as well as chemical methods. Biological treatment of hydrogen sulphide typically involves passing the biogas through biologically active media. These treatments may include open bed soil filters, biofilters, fixed film bioscrubbers, suspended growth bioscrubbers and fluidized bed bioreactors.

Biological Desulphurization

The simplest method of desulphurization is the addition of oxygen or air directly into the digester or in a storage tank serving at the same time as gas holder. Thiobacilli are ubiquitous and thus systems do not require inoculation. They grow on the surface of the digestate, which offers the necessary micro-aerophilic surface and at the same time the necessary nutrients. They form yellow clusters of sulphur. Depending on the temperature, the reaction time, the amount and place of the air added the hydrogen sulphide concentration can be reduced by 95 % to less than 50 ppm.

Most of the sulphide oxidising micro-organisms belong to the family of Thiobacillus. For the microbiological oxidation of sulphide it is essential to add stoichiometric amounts of oxygen to the biogas. Depending on the concentration of hydrogen sulphide this corresponds to 2 to 6 % air in biogas. Measures of safety have to be taken to avoid overdosing of air in case of pump failures.

Biofiltration

Biofiltration is one of the most promising clean technologies for reducing emissions of malodorous gases and other pollutants into the atmosphere. In a biofiltration system, the gas stream is passed through a packed bed on which pollutant-degrading microbes are immobilized as biofilm. A biological filter combines water scrubbing and biological desulfurization. Biogas and the separated digestate meet in a counter-current flow in a filter bed. The biogas is mixed with 4% to 6% air before entry into the filter bed. The filter media offer the required surface area for scrubbing, as well as for the attachment of the desulphurizing microorganisms. Microorganisms in the biofilm convert the absorbed H2S into elemental sulphur by metabolic activity. Oxygen is the key parameter that controls the level of oxidation.

The capital costs for biological treatment of biogas are moderate and operational costs are low. This technology is widely available worldwide. However, it may be noted that the biological system is capable to remove even very high amounts of hydrogen sulphide from the biogas but its adaptability to fluctuating hydrogen sulphide contents is not yet proven.

The Ultimate Guide To Convert Your Home Into A Smart Home

Smartphones are fast becoming a reality these days. With more and more brands and companies launching a variety of different smart lighting systems, speakers, sensors, it is easier than ever to convert your home into a smart home. If you have no prior experience in creating a smart home, it can be a confusing task to choose the right kind of devices. Moreover, you might not even know the solutions available to convert your home into a smart home. That is why it is vital to first understand how to transform your home into a smart home.

If you’re worried about the expenses, there are many ways in which you can create a smart home within your budget. It will allow you to control the various aspects of your home without having to spend a significant amount of money.

Moreover, the products available these days are becoming more and more affordable. As a result, it is easier to build a smart home. We will today list a step-by-step guide which will allow you to convert your home into a smart home.

  1. Smart lighting

Lighting systems are the best way to control the appearance of your home. Moreover, when you opt for a smart lighting system, you can easily control the ambiance of the house with the help of a Wi-Fi connection. Most of them offer a mobile application through which, you can efficiently manage the entire lighting system. Every light on the lighting system connects to the central hub.

Therefore, controlling it is easier than ever. When you’re looking at the individual bulbs which you can buy and integrate with the Wi-Fi connection at home, you can opt for the ones from TP-Link and LIFX. These products are not only compatible with the Wi-Fi connection, but many of them work along with Bluetooth as well.

Some of the other well-known companies who sell such smart bulbs include Philips Hue, Sengled Element. These, however, can be controlled by Zigbee signals which in turn work along with the Wi-Fi signal. Ultimately, A router can control them. You can manage these with the help of the app on your smartphone. The app will work on any Android-based device. As a result, programming the light according to the theme selected in the app is not a problem at all.

In case, you want to automate your existing lighting system you can change the switches and replaced them with smart switches and cameras. You can use smartphone applications to control them. Some of the companies which sell the smart switches are TP-LINK, Ecobee, Leviton, etc. these switches are directly controllable through Wi-Fi. It will not require a central hub. That is why; you can save a significant amount of money by going for the switches. If you want a centralized system, you can go with Noon Home’s system. It is comparatively expensive, but it allows you to have complete control over the lighting system. Thus, when it comes to smart lighting, there are a wide variety of options available.

  1. Smart speakers

Smart speakers play a significant role in a smart-home. You can control the various functions of the house using the voice commands. As a result, they work as an assistant to control every aspect of your home. You can go with the Google home speaker or the Amazon Echo speaker. The choice is entirely up to you. If you want a single speaker to control the various options, you can go with Amazon Echo speaker.

On the other hand, if you’re going to create a series of such points in your home, you can go with the Google home series. Google series works on the fact that you can install multiple speakers throughout your home and one in each room to control every aspect of your home. That is why, if you want to create a network of smart devices, Google home is the perfect option for you.

Google home is controlled using Google assistant. Amazon Echo devices are controlled using Amazon Alexa. Even Lenovo sells quick display series which work using Google home.

Lenovo is not alone, which is integrating these devices along with its offerings. Various other device manufacturers are doing the same. That is why, when you want to incorporate the smart speakers in your home, it is easier to do so. You can create the entire ecosystem of smart devices and control TVs, lights, thermostats, and a variety of other functions of your home with the help of these speakers.

  1. Smart thermostats

Climate control systems in our home consume the maximum amount of energy. Moreover, when the weather is at extremes, they make sure that the ambiance in your home is entirely comfortable. These days, people are using Usave.co.uk for energy comparison and choosing the right energy supplier. You can go a step further and save even more energy with the help of smart thermostats. These ensure that you can easily control the ambiance of your home. These thermostats have a predictive system which means that they can set the temperature of the house conveniently and on their own.

When you look at the basic working of these thermostats, they require you to set up sensors everywhere in your home. They control the temperature precisely in the part of the house where you are present. They also keep the rest of the home like the passageways at a comfortable temperature. However, precise control is in the area in which the individuals are present. Hence, there is a significant amount of energy saving. Thus, when you want to control the temperature of your home efficiently, smart thermostats are the perfect option.

  1. Home Security Cameras

When converting your home into a smart one, it is also essential to make it more secure. The smart-homes are easy to secure as they rely on sensors and devices rather than individuals. It is even more affordable as compared to hiring security guards. The best tool which you have got to handle the security of your home in a smarter way is the smart camera. With the help of the smart-camera, it is easier to monitor your home.

Moreover, when there is any unusual activity in your home, you can get alert easily. Also, the smart cameras which we are speaking about are not just helpful for detecting intrusions or burglary, but also can help you in monitoring your children and pets. They are multipurpose which means that you can use them for the application which you prefer.

Some of the options which you have when it comes to smart cameras are:

  • Ring
  • Netatmo
  • Maximum

The advantage of smart cameras is that they incorporate lights and a variety of different motion sensors into the security system. They also integrate the doorbell so that you can easily monitor the entry and exit points of your home. You can communicate with the individuals at the entrance and exit points without having to open the door at all. You can do so remotely as well. As a result, you can control the access to your home remotely or from your smartphone without any problem.

The motion sensors ensure that you get an alert whenever there is unusual activity in the monitored area. As a result, you always get alerts about any intrusion or unfriendly individuals even before they enter your home. The smart cameras are easy to install and do not require any unique fixtures which ensures that you can make the security of your home smarter by merely installing these cameras and connecting them with the Wi-Fi system.

  1. Smart audio systems

The multi-room audio systems ensure that you can get that you get entertainment in every room. There are options to choose from like:

  • Sonos
  • Yamaha
  • HEOS

These are self-contained speakers. You can keep them in every room and connect them with the Wi-Fi. They will help you to stream the music. Moreover, they can stream music from a variety of different services like Spotify. You can also select the tracks through your smartphone.

The difference between the speakers and something like Amazon Echo or Google home systems is that these speakers have a much better audio quality. They are not just for listening to commands, but actually up the entertainment quotient. Moreover, they can be integrated with TV and enhance your music watching experience. You can control them with the help of the tablet or the smartphone without any problem.

When speaking about something like Sonos, it works with the help of Amazon Alexa digital assistant. As a result, you can integrate it into your smartphone without any problem. Thus, when looking up the entertainment question and make your entertainment devices smarter, these are the speakers which you should choose.

  1. Smart sensors

The sensors play the role of eyes and ears in any smart-home system. Without sensors, it will be challenging to control the functions of a smart-home. The smart sensors ensure that they detect motion inside and outside the home. Inside the house, they correct the climate control system to make the ambiance more habitable. Also, they can switch on and off the lights depending on whether a room is vacant or not. Hence, it becomes easier for you to automate the climate control system.

Additionally, some of the sensors are used for smoke detection as well. The smoke detection sensors alert the smartphone numbers which you input as well. You can authorize a contact to get an alert with the help of the smart sensors. As a result, whenever there is a problem at your home, the authorized contacts will get an instant alert as well. When those contacts get a warning, they can act accordingly and arrange for the emergency services to reach your home as well. The sensors are not just available for fire detection.

There are the sensors which monitor the air quality of your home as well. These sensors, especially monitor the carbon monoxide levels. Accordingly, it instructs the climate control system to filter the air or the air purifier to activate. The more the number of sensors the more precisely each smart device can operate.

Also, there are smart smoke alarms available. The Nest Protect is such a smoke alarm system. It has emergency lights as well to show you the way out. Moreover, it sends an alert to your contacts as well. When it comes to sensors, they can accomplish a wide variety of factors. It is wise to use such sensors in your home to make your home smarter and safer.

  1. Smart irrigation system

Technology is available to automate every system of your home. That is why, if you’re worried about manually doing the lawn and garden irrigation, you don’t need to worry anymore. The smart irrigation systems can automatically detect the moisture in your lawn or your garden. As a result, they can use the irrigation devices to ensure that you can water the garden or backyard. They also take into account the type of plants which you have.

Moreover, if you do not want to automate them, you can control them through your app. You can install duplicators or sprinkle indicators. When you manage them with the help of the app, they will start and stop according to your commands. As a result, without having to control the irrigation devices manually, you can efficiently manage your garden or your lawn. When you do that, you can be sure that the plants or the garden will always be in proper condition.

The advantage of smartphone app control is that even when traveling, you can water your lawn as well as your garden without any problem. It will ensure that you don’t need to hire anyone else to take care of the lawn or garden irrigation.

Final Words

So, when it comes to converting your home into a smart-home, these are the seven steps which you need to follow. Each of the above steps deals with a different system. With the help of these seven smart home systems, it is easier than ever to automate various aspects of your home.

You can control them from your mobile application as well which will ensure that you can customize each element of your home remotely. In the process, you can also save a significant amount of resources and utilities. With smart-systems becoming more and more affordable, now there is no reason why you should not convert your home into a smart-home.

A Primer on Biofuels

The term ‘Biofuel’ refers to liquid or gaseous fuels for the transport sector that are predominantly produced from biomass. A variety of fuels can be produced from biomass resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The biomass resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues.

The agricultural resources include grains used for biofuels production, animal manures and residues, and crop residues derived primarily from corn and small grains (e.g., wheat straw). A variety of regionally significant crops, such as cotton, sugarcane, rice, and fruit and nut orchards can also be a source of crop residues. The forest resources include residues produced during the harvesting of forest products, fuelwood extracted from forestlands, residues generated at primary forest product processing mills, and forest resources that could become available through initiatives to reduce fire hazards and improve forest health. Municipal and urban wood residues are widely available and include a variety of materials — yard and tree trimmings, land-clearing wood residues, wooden pallets, organic wastes, packaging materials, and construction and demolition debris.

Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking. Biofuel industries are expanding in Europe, Asia and the Americas. Biofuels are generally considered as offering many priorities, including sustainability, reduction of greenhouse gas emissions, regional development, social structure and agriculture, and security of supply.

First-generation biofuels are made from sugar, starch, vegetable oil, or animal fats using conventional technology. The basic feedstocks for the production of first-generation biofuels come from agriculture and food processing. The most common first-generation biofuels are:

  • Biodiesel: extraction with or without esterification of vegetable oils from seeds of plants like soybean, oil palm, oilseed rape and sunflower or residues including animal fats derived from rendering applied as fuel in diesel engines
  • Bioethanol: fermentation of simple sugars from sugar crops like sugarcane or from starch crops like maize and wheat applied as fuel in petrol engines
  • Bio-oil: thermo-chemical conversion of biomass. A process still in the development phase
  • Biogas: anaerobic fermentation or organic waste, animal manures, crop residues an energy crops applied as fuel in engines suitable for compressed natural gas.

First-generation biofuels can be used in low-percentage blends with conventional fuels in most vehicles and can be distributed through existing infrastructure. Some diesel vehicles can run on 100 % biodiesel, and ‘flex-fuel’ vehicles are already available in many countries around the world.

Second-generation biofuels are derived from non-food feedstock including lignocellulosic biomass like crop residues or wood. Two transformative technologies are under development.

  • Biochemical: modification of the bio-ethanol fermentation process including a pre-treatment procedure
  • Thermochemical: modification of the bio-oil process to produce syngas and methanol, Fisher-Tropsch diesel or dimethyl ether (DME).

Advanced conversion technologies are needed for a second generation of biofuels. The second generation technologies use a wider range of biomass resources – agriculture, forestry and waste materials. One of the most promising second-generation biofuel technologies – ligno-cellulosic processing (e. g. from forest materials) – is already well advanced. Pilot plants have been established in the EU, in Denmark, Spain and Sweden.

Third-generation biofuels may include production of bio-based hydrogen for use in fuel cell vehicles, e.g. Algae fuel, also called oilgae. Algae are low-input, high-yield feedstocks to produce biofuels.

Gasification of Municipal Wastes

utishinai-gasification-plantGasification of municipal wastes involves the reaction of carbonaceous feedstock with an oxygen-containing reagent, usually oxygen, air, steam or carbon dioxide, generally at temperatures above 800°C. The process is largely exothermic but some heat may be required to initialise and sustain the gasification process. The main product of the gasification process is syngas, which contains carbon monoxide, hydrogen and methane. Typically, the gas generated from gasification has a low heating value (LHV) of 3 – 6 MJ/Nm3.The other main product produced by gasification is a solid residue of non-combustible materials (ash) which contains a relatively low level of carbon. Syngas can be used in a number of ways, including:

  • Syngas can be burned in a boiler to generate steam for power generation or industrial heating.
  • Syngas can be used as a fuel in a dedicated gas engine.
  • Syngas, after reforming, can be used in a gas turbine
  • Syngas can also be used as a chemical feedstock.

Gasification has been used worldwide on a commercial scale for several decades by the chemical, refining, fertilizer and electric power industries. MSW gasification plants are relatively small-scale, flexible to different inputs and modular development. The quantity of power produced per tonne of waste by gasification process is larger than when applying the incineration method. The most important reason for the growing popularity of gasification of municipal wastes has been the increasing technical, environmental and public dissatisfaction with the performance of conventional incinerators.

Plasma Gasification

Plasma gasification uses extremely high temperatures in an oxygen-starved environment to completely decompose input waste material into very simple molecules in a process similar to pyrolysis. The heat source is a plasma discharge torch, a device that produces a very high temperature plasma gas. It is carried out under oxygen-starved conditions and the main products are vitrified slag, syngas and molten metal.

plasma-gasification

Vitrified slag may be used as an aggregate in construction; the syngas may be used in energy recovery systems or as a chemical feedstock; and the molten metal may have a commercial value depending on quality and market availability. The technology has been in use for steel-making and is used to melt ash to meet limits on dioxin/furan content. There are several commercial-scale plants already in operation in Japan for treating MSW and auto shredder residue.

Advantages of Gasification

There are numerous solid waste gasification facilities operating or under construction around the world. Gasification of solid wastes has several advantages over traditional combustion processes for MSW treatment. It takes place in a low oxygen environment that limits the formation of dioxins and of large quantities of SOx and NOx. Furthermore, it requires just a fraction of the stoichiometric amount of oxygen necessary for combustion. As a result, the volume of process gas is low, requiring smaller and less expensive gas cleaning equipment.

The lower gas volume also means a higher partial pressure of contaminants in the off-gas, which favours more complete adsorption and particulate capture. Finally, gasification generates a fuel gas that can be integrated with combined cycle turbines, reciprocating engines and, potentially, with fuel cells that convert fuel energy to electricity more efficiently than conventional steam boilers.

Disadvantages of Gasification

The gas resulting from gasification of municipal wastes contains various tars, particulates, halogens, heavy metals and alkaline compounds depending on the fuel composition and the particular gasification process. This can result in agglomeration in the gasification vessel, which can lead to clogging of fluidised beds and increased tar formation. In general, no slagging occurs with fuels having ash content below 5%. MSW has a relatively high ash content of 10-12%.

Cofiring of Biomass

Cofiring of biomass with coal and other fossil fuels can provide a short-term, low-risk, low-cost option for producing renewable energy while simultaneously reducing the use of fossil fuels. Cofiring (or co-combustion) involves utilizing existing power generating plants that are fired with fossil fuel (generally coal), and displacing a small proportion of the fossil fuel with renewable biomass fuels.

Biomass can typically provide between 3 and 15 percent of the input energy into the power plant. Cofiring of biomass has the major advantage of avoiding the construction of new, dedicated, biomass power plant. An existing power station is modified to accept the biomass resource and utilize it to produce a minor proportion of its electricity.

Cofiring of biomass may be implemented using different types and percentages of biomass in a range of combustion and gasification technologies. Most forms of biomass are suitable for co-firing. These include dedicated energy crops, urban wood waste and agricultural residues such as rice straw and rice husk.

The fuel preparation requirements, issues associated with combustion such as corrosion and fouling of boiler tubes, and characteristics of residual ash dictate the co-firing configuration appropriate for a particular plant and biomass resource. These configurations may be categorized into direct, indirect and parallel firing.

Direct Co-Firing

This is the most common form of biomass co-firing involving direct co-firing of the biomass fuel and the primary fuel (generally coal) in the combustion chamber of the boiler. The cheapest and simplest form of direct co-firing for a pulverized coal power plant is through mixing prepared biomass and coal in the coal yard or on the coal conveyor belt, before the combined fuel is fed into the power station boiler.

Indirect Co-firing

If the biomass fuel has different attributes to the normal fossil fuel, then it may be prudent to partially segregate the biomass fuel rather than risk damage to the complete station.

For indirect co-firing, the ash of the biomass resource and the main fuel are kept separate from one another as the thermal conversion is partially carried out in separate processing plants. As indirect co-firing requires a separate biomass energy conversion plant, it has a relatively high investment cost compared with direct co-firing.

Parallel Firing

For parallel firing, totally separate combustion plants and boilers are used for the biomass resource and the coal- fired power plants. The steam produced is fed into the main power plant where it is upgraded to higher temperatures and pressures, to give resulting higher energy conversion efficiencies. This allows the use of problematic fuels with high alkali and chlorine contents (such as wheat straw) and the separation of the ashes.

Utilization of Date Palm Biomass

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.

date-wastes

Date palm biomass is found in large quantities across the Middle East

Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in dates-producing nations.

The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date palm residues an excellent biomass resource in date-palm producing nations.

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

A wide range of physico-chemical, thermal and biochemical technologies exists for sustainable utilization of date palm biomass. Apart from charcoal production and energy conversion (using technologies like combustion and gasification), below are few ways for utilization of date palm wastes:

Conversion into fuel pellets or briquettes

Biomass pellets are a popular type of alternative fuel (analogous to coal), generally made from wood wastes and agricultural biomass. The biomass pelletization process consists of multiple steps including pre-treatment, pelletization and post-treatment of biomass wastes. Biomass pellets can be used as a coal replacement in power plant, industries and other application.

Conversion into energy-rich products

Biomass pyrolysis is the thermal decomposition of date palm biomass occurring in the absence of oxygen. The products of biomass pyrolysis include biochar, bio-oil and gases including methane, hydrogen, carbon monoxide, and carbon dioxide.

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.

Bio-oil can be upgraded to either a special engine fuel or through gasification processes to a syngas which can then be processed into biofuels. Bio-oil is particularly attractive for co-firing because it can be more readily handled and burned than solid fuel and is cheaper to transport and store.

Conversion into biofertilizer

Composting is the most popular method for biological decomposition of organic wastes. Date palm waste has around 80% organic content which makes it very well-suited for the composting process. Commercial-scale composting of date palm wastes can be carried out by using the traditional windrow method or a more advanced method like vermicomposting.

Environmental Considerations When Using Drum Heaters

For people in the colder parts of the world, temperatures can become an issue. Sometimes, you might need to keep your liquids, water or fuel at the normal room temperature. The main use of drum heaters is that they work as storages that keep their content at a certain temperature.

Barrel heaters are especially needed if their content loses its nature and benefits due to a drop or a rise in the temperature. It is a cheap solution for maintaining high energy without paying for its cost, in addition you are reducing the pollution since the energy is being recycled within the system. So, what do you need to consider when you are using drum heaters? That is what we are going to tackle.

Harsh weather

Harsh environmental conditions, especially the low temperature of the cold months, might push the need to use a heater for your drums to avoid causing them any damages to keep them in ultimate condition. Buying good drum heater jackets will keep you away from breaking the bank just to save your desired content. They don’t only keep your drums at the required temperature, they also save and lower the viscosity of the fluids so you wouldn’t need to replace them as often and more importantly, they protect them from freezing in harsh cold environment conditions.

Energy saving

Electrical insulated heating jackets offer more protection from cold or freezing due to the extra layer of insulation they have. With heat loss kept at minimum, the heating jackets offer more energy saving options which make their power consumption drop automatically, this also translates to cost of operation drop. What’s even more positive about these jackets is that they are normally designed to cover the whole containers, thus you are more likely to be saved from any energy loss.

Using some types of barrel heaters that do not cover the whole drum might waste energy as they naturally get hot. Due to thermodynamics basics, the heat will start dissipating from the higher-temperature surface to the cold atmosphere. That is why when using the right type of heater for your needs, make sure that it will cover the whole container you have so you don’t waste any energy.

Saving space = saving energy

An extra step to save money and time is to place your drums in a closed space. Open spaces make it harder to maintain your drums at desired temperatures. Putting your drums and barrels in an enclosed space will ensure that no energy is wasted to the atmosphere and manage heat escape.

Choose the one that works best for you

When you are first buying the heater, it is always a good step to buy one that is flexible. Drum heaters are really simple on the design side, however, using one that does not fit may create more of a problem than it solves. Buying a good drum heater that is adjustable or can fit any type of container you have, is always a smart idea to save you from the headache and wasting your money.

Different Strategies in Composting

Composting can be categorized into different categories depending on the nature of decomposition process. The three major segments of composting are anaerobic composting, aerobic composting, and vermicomposting. In anaerobic composting, the organic matter is decomposed in the absence of air. Organic matter may be collected in pits and covered with a thick layer of soil and left undisturbed six to eight months. Anaerobic microorganisms dominate and develop intermediate compounds including methane, organic acids, hydrogen sulphide and other substances. The process is low-temperature, slow and the compost formed may not be completely converted and may include aggregated masses and phytotoxic compounds.

Aerobic Composting

Aerobic composting is the process by which organic wastes are converted into compost or manure in presence of air. In this process, aerobic microorganisms break down organic matter and produce carbon dioxide, ammonia, water, heat and humus, the relatively stable organic end-product. Although aerobic composting may produce intermediate compounds such as organic acids, aerobic microorganisms decompose them further. The resultant compost, with its relatively unstable form of organic matter, has little risk of phytotoxicity. The heat generated accelerates the breakdown of proteins, fats and complex carbohydrates such as cellulose and hemicellulose. Hence, the processing time is shorter. Moreover, this process destroys many micro-organisms that are human or plant pathogens, as well as weed seeds, provided it undergoes sufficiently high temperature. Although more nutrients are lost from the materials by aerobic composting, it is considered more efficient and useful than anaerobic composting for agricultural production.

There are a variety of methods for aerobic composting, the most common being the Heap Method, where organic matter needs to be divided into three different types and to be placed in a heap one over the other, covered by a thin layer of soil or dry leaves. This heap needs to be mixed every week, and it takes about three weeks for conversion to take place. The process is same in the Pit Method, but carried out in specially constructed pits. Mixing has to be done every 15 days, and there is no fixed time in which the compost may be ready. Berkley Method uses a labor-intensive technique and has precise requirements of the material to be composted. Easily biodegradable materials, such as grass, vegetable matter, etc., are mixed with animal matter in the ratio of 2:1. Compost is usually ready in 15 days.

Vermicomposting

Vermicomposting is a type of composting in which certain species of earthworms are used to enhance the process of organic waste conversion and produce a better end-product. It is a mesophilic process utilizing microorganisms and earthworms. Earthworms feeds the organic waste materials and passes it through their digestive system and gives out in a granular form (cocoons) which is known as vermicompost. Earthworms consume organic wastes and reduce the volume by 40–60 percent. Each earthworm weighs about 0.5 to 0.6 gram, eats waste equivalent to its body weight and produces cast equivalent to about 50 percent of the waste it consumes in a day. The moisture content of castings ranges between 32 and 66 percent and the pH is around 7.

The level of nutrients in compost depends upon the source of the raw material and the species of earthworm. Apart from other nutrients, a fine worm cast is rich in NPK which are in readily available form and are released within a month of application. Vermicompost enhances plant growth, suppresses disease in plants, increases porosity and microbial activity in soil, and improves water retention and aeration.