Energy Potential of Palm Kernel Shells

palm-kernel-shellsThe Palm Oil industry in Southeast Asia and Africa generates large quantity of biomass wastes whose disposal is a challenging task. Palm kernel shells (or PKS) are the shell fractions left after the nut has been removed after crushing in the Palm Oil mill. Kernel shells are a fibrous material and can be easily handled in bulk directly from the product line to the end use. Large and small shell fractions are mixed with dust-like fractions and small fibres. Moisture content in kernel shells is low compared to other biomass residues with different sources suggesting values between 11% and 13%.

Palm kernel shells contain residues of Palm Oil, which accounts for its slightly higher heating value than average lignocellulosic biomass. Compared to other residues from the industry, it is a good quality biomass fuel with uniform size distribution, easy handling, easy crushing, and limited biological activity due to low moisture content. PKS can be readily co-fired with coal in grate fired -and fluidized bed boilers as well as cement kilns in order to diversify the fuel mix.

The primary use of palm kernel shells is as a boiler fuel supplementing the fibre which is used as primary fuel. In recent years kernel shells are sold as alternative fuel around the world. Besides selling shells in bulk, there are companies that produce fuel briquettes from shells which may include partial carbonisation of the material to improve the combustion characteristics. As a raw material for fuel briquettes, palm shells are reported to have the same calorific characteristics as coconut shells. The relatively smaller size makes it easier to carbonise for mass production, and its resulting palm shell charcoal can be pressed into a heat efficient biomass briquette.

Palm kernel shells have been traditionally used as solid fuels for steam boilers in palm oil mills across Southeast Asia. The steam generated is used to run turbines for electricity production. These two solid fuels alone are able to generate more than enough energy to meet the energy demands of a palm oil mill. Most palm oil mills in the region are self-sufficient in terms of energy by making use of kernel shells and mesocarp fibers in cogeneration. In recent years, the demand for palm kernel shells has increased considerably in Europe, Asia-Pacific, China etc resulting in price close to that of coal. Nowadays, cement industries and power producers are increasingly using palm kernel shells to replace coal. In grate-fired boiler systems, fluidized-bed boiler systems and cement kilns, palm kernel shells are an excellent fuel.

Cofiring of PKS yields added value for power plants and cement kilns, because the fuel significantly reduces carbon emissions – this added value can be expressed in the form of renewable energy certificates, carbon credits, etc. However, there is a great scope for introduction of high-efficiency cogeneration systems in the industry which will result in substantial supply of excess power to the public grid and supply of surplus PKS to other nations. Palm kernel shell is already extensively in demand domestically by local industries for meeting process heating requirements, thus creating supply shortages in the market.

Palm oil mills around the world may seize an opportunity to supply electricity for its surrounding plantation areas using palm kernel shells, empty fruit branches and palm oil mill effluent which have not been fully exploited yet. This new business will be beneficial for all parties, increase the profitability for palm oil industry, reduce greenhouse gas emissions and increase the electrification ratio in surrounding plantation regions.

Salient Features of Sugar Industry in Mauritius

Sugar industry has always occupied a prominent position in the Mauritian economy since the introduction of sugarcane around three centuries ago. Mauritius has been a world pioneer in establishing sales of bagasse-based energy to the public grid, and is currently viewed as a model for other sugarcane producing countries, especially the developing ones.

Sugar factories in Mauritius produce about 600,000 tons of sugar from around 5.8 million tons of sugarcane which is cultivated on an agricultural area of about 72,000 hectares. Of the total sugarcane production, around 35 percent is contributed by nearly 30,000 small growers. There are more than 11 sugar factories presently operating in Mauritius having crushing capacities ranging from 75 to 310 tons cane per hour.

During the sugar extraction process, about 1.8 million tons of Bagasse is produced as a by-product, or about one third of the sugarcane weight. Traditionally, 50 percent of the dry matter is harvested as cane stalk to recover the sugar with the fibrous fraction, i.e. Bagasse being burned to power the process in cogeneration plant. Most factories in Mauritius have been upgraded and now export electricity to the grid during crop season, with some using coal to extend production during the intercrop season.

Surplus electricity is generated in almost all the sugar mills. The total installed capacity within the sugar industry is 243 MW out of which 140 MW is from firm power producers. Around 1.6 – 1.8 million tons of bagasse (wet basis) is generated on an annually renewable basis and an average of around 60 kWh per ton sugarcane is generated for the grid throughout the island.

The surplus exportable electricity in Mauritian power plants has been based on a fibre content ranging from 13- 16% of sugarcane, 48% moisture content in Bagasse, process steam consumption of 350–450 kg steam per ton sugarcane and a power consumption of 27-32 kWh per ton sugarcane.

In Mauritius, the sugarcane industry is gradually increasing its competitiveness in electricity generation. It has revamped its boiler houses by installing high pressure boilers and condensing extraction steam turbine. All the power plants are privately owned, and the programme has been a landmark to show how all the stakeholders (government, corporate and small planters) can co-operate. The approach is being recommended to other sugarcane producing countries worldwide to harness the untapped renewable energy potential of biomass wastes from the sugar industry.

Why You Should Be Investing in Solar Panels

The future is green, and it’s more important to get on board with it than ever before. The past year has seen countless climate-change related natural disasters, from the recent devastating mega-fires in California to frequent hurricanes sweeping the US and the Caribbean.

Solar panels are becoming much more accessible, for homeowners and for businesses. Traditional roof-rack solar panels can now be installed for as little as around $3,000, and are practically a no-brainer due to the energy savings you’ll make over time (you could even totally eliminate your electricity bill). Not to mention that you’ll be doing your part to help the environment in our planet’s time of need.

If you’ve always found chunky solar panels ugly and off-putting, business magnate Elon Musk has a solution. His electric car and solar panel company Tesla has recently unveiled invisible solar roof tiles. The tiles look exactly like normal roof slates, but capture the sun’s energy without drawing attention. These tiles are paving the way to normalizing sustainable, beautiful eco-homes.

To further convince you about seriously considering installing solar panels for your home, check out our list of top reasons why solar panels will benefit your household or business.

Slash Your Energy Bills

After the initial investment of purchasing the panels and installation, the energy produced is all yours. Even if you consume more energy than your panels can produce, you’ll make drastic savings on what you are currently paying by purchasing all your electricity from the grid.

You’ll make even more amazing savings if you live in a sunny state or country – prices in Brisbane, Australia, are particularly low to purchase and install solar panels. And as the city enjoys on average 261 days of sun per year, panels there will produce more than enough energy to power homes all year round.

Energy costs are only set to rise and rise – meaning that by investing in solar panels now, you’ll never feel the strain of your electricity bills going up again. This is an especially smart idea for business owners with fluctuating income, as you can more easily predict your cashflow with fixed energy prices.

Increase the Value of Your Home

If you are open to the possibility of moving to a new house in the future, you will be able to sell your current property at an increased value by equipping it with solar panels. It’s an attractive prospect for buyers if a potential home comes with very small or no electricity bills, so you’ll be making a huge return on your investment in this way, too.

Note: Be wary of ‘renting your roof’ to solar panel companies if you can’t afford to purchase the panels outright. You may want to ‘go green’ in any way you can, but buying panels is by far the most practical way to enjoy the benefits. The lengthy leases that come with rental panel contracts (often 25 years) have been seen to put off mortgage lenders. It’s highly recommended that if you want to benefit from free electricity and help the environment with solar, you should save up first to increase the value of your property – not render it unsellable.

Reduce Your Carbon Footprint

As we said, it’s never been so important to do your bit to save our eco-system. The polar ice caps are melting faster than has ever been recorded, and the earth is suffering terrible effects. As well as hurricanes and fires, we’ve also experienced floods, earthquakes and landslides all over the world this year.

Solar panels are becoming more accessible, for homeowners and businesses

In the large scheme of things, installing solar panels doesn’t seem like it will help much, but if everyone did their part to be more eco-conscious, we could significantly reduce the strain of destructive fossil fuels on the environment. By equipping your property with solar panels, you will save money while making steps to saving the environment – a tough offer to turn down!

Utilizing green energy within your business has even better rewards. Marketing your business as eco-conscious and sustainable is a great way to attract customers and impress existing ones. In recent years, studies into consumer activity have found that sustainability is a big shopping priority, especially among the millennial generation. Corporate solar panels will increase your revenue by expanding your customer base AND saving your business’s energy bills.

So – what are you waiting for? Contact a solar energy company today, who will be more than happy to assist you on your green energy journey.

Bagasse-Based Cogeneration in Pakistan: Challenges and Opportunities

Considering the fact that Pakistan is among the world’s top-10 sugarcane producers, the potential of generating electricity from bagasse is huge.  Almost all the sugar mills in Pakistan have in-house plants for cogeneration but they are inefficient in the consumption of bagasse. If instead, high pressure boilers are installed then the production capacity can be significantly improved with more efficient utilization of bagasse.

However, due to several reasons; mostly due to financing issues, the sugar mill owners were not able to set up these plants. Only recently, after financial incentives have been offered and a tariff rate agreed upon between the government and mill owners, are these projects moving ahead.

The sugar mill owners are more than willing to supply excess electricity generated form the in-house power plants to the national grid but were not able to before, because they couldn’t reach an agreement with the government over tariff. The demand for higher tariff was justified because of large investments in setting up new boilers. It would also have saved precious foreign exchange which is spent on imported oil.

By estimating the CDM potential of cogeneration (or CHP) projects based on biofuels, getting financing for these projects would be easier. Renewable energy projects can be developed through Carbon Development Mechanism or any other carbon credit scheme for additional revenue.

Since bagasse is a clean fuel which emits very little carbon emissions it can be financed through Carbon Development Mechanism. One of the reasons high cogeneration power plants are difficult to implement is because of the high amount of costs associated. The payback period for the power plants is unknown which makes the investors reluctant to invest in the high cogeneration project. CDM financing can help improve the rate of return of the project.

Bagasse power plants generate Carbon Emission Reductions in 2 ways; one by replacing electricity produced from fossil fuels.  Secondly if not used as a fuel, it would be otherwise disposed off in an unsafe manner and the methane emissions present in biomass would pollute the environment far more than CO2 does.

Currently there are around 83 sugar mills in Pakistan producing about 3.5 million metric tons of sugar per annum with total crushing capacity 597900 TCD, which can produce approximately 3000 MW during crop season Although it may seem far-fetched at the moment, if the government starts to give more attention to  sugar industry biomass rather than coal, Pakistan can fulfill its energy needs without negative repercussions or damage to the environment.

However some sugar mills are opting to use coal as a secondary fuel since the crushing period of sugarcane lasts only 4 months in Pakistan. The plants would be using coal as the main fuel during the non-crushing season. The CDM effect is reduced with the use of coal. If a high cogeneration plant is using even 80% bagasse and 20% of coal then the CERs are almost nullified. If more than 20% coal is used then the CDM potential is completely lost because the emissions are increased. However some sugar mills are not moving ahead with coal as a secondary fuel because separate tariff rates have to be obtained for electricity generation if coal is being used in the mix which is not easily obtained.

Pakistan has huge untapped potential for bagasse-based power generation

One of the incentives being offered by the State Bank of Pakistan is that if a project qualifies as a renewable project it is eligible to get loan at 6% instead of 12%. However ones drawback is that, in order to qualify as a renewable project, CDM registration of a project is not taken into account.

Although Pakistan is on the right track by setting up high cogeneration power plants, the use of coal as a secondary fuel remains debatable.  The issue that remains to be addressed is that with such huge amounts of investment on these plants, how to use these plants efficiently during non-crushing period when bagasse is not available. It seems almost counter-productive to use coal on plants which are supposed to be based on biofuels.

Conclusion

With the demand for energy in Pakistan growing, the country is finally exploring alternatives to expand its power production. Pakistan has to rely largely on fossils for their energy needs since electricity generation from biomass energy sources is considered to be an expensive option despite abundance of natural resources. However by focusing on growing its alternate energy options such as bagasse-based cogeneration, the country will not only mitigate climate change but also tap the unharnessed energy potential of sugar industry biomass.

Renewable Energy Production in Australia: The Plan to Reduce Coal Use

Recently there has been a lot of talk in how a country can improve their ecological footstep. One way of doing so is definitely changing the way the respective country produces its energy. Australia has recently been headlining the news in regard to the renewable energy situation. Australia’s energy production is looking towards a new future with a specific aim on solar and wind power.

If Australia plans on keeping its water resource at a steady level, it has got to go from its use of coal to renewable sources. Thanks to its abundance in both solar and wind energy, Australia has quite the advantage when it comes to green energy production possibilities.

Unfortunately though due to their geographic position, the water supply is limited for the country. So much so, that the coal industry was taking a toll on the water supply due to the large quantities of water needed when producing energy from coal. As a result, moving over to wind and solar energy fueled productions is a viable option seeing how both respective energy productions do not require water.

The news that Australia was listed as a “water-stressed company” was released by the World Resource Institute; a non-profit organization based in Washington D.C. Moreover, on this past May 13th The Sydney Morning Herald also wrote that 73% of Australia’s electricity needs were met by the use of coal. In respect to these findings and Australia’s continuous growth, it is imperative that new resources are used for energy production.

Australia has been making headlines in renewable energy sector.

Fortunately, Australia’s geography is a big resource as well when it comes to studying the possibilities of implementing the new energy productions. It was in fact calculated that the dimensions of the solar power farm needed to meet the country’s demands would result in occupying only 0.1% of Australia’s total land mass; I think we can all agree on the fact that that land could be spared for a solar farm.

And on that note, the government is taking the matter seriously, and has called upon everybody to try and better the situation. The incentives call upon small businesses and households as well by reminding them that there are the possibilities of installing their own solar panels, heat pumps, solar water heaters, and more.

Thanks to the various incentives, the Green Energy Council has stated that there is a lot of activity in the sector, including at least 58 different projects focused on implementing the renewable energy sources. As a consequence of these projects, the council has also stated that there would be an income of $10 billion in investments, 6,141 new jobs, and 5,482 megawatts of renewable energy capacity. Definitely great numbers to look forward to!

Tackling China’s Smog Problem with Renewable Energy

smog-chinaChina is currently facing serious environmental problems, with potentially few solutions. Currently, this is mostly taking the form of serious smog issues plaguing North China, with more than 24 cities on red alert. However, with airports being shut down due to lacking visibility and the economy of China being heavily disrupted, action needs to be taken to solve this serious smog problem.

While limited action has been taken, perhaps renewable energy is the key to cutting down China’s smog.

How Bad Is the Problem?

The smog problem in China has become increasing worse from 2015 to 2017, with more than 90 micrograms of pollution per meter squared. These levels of air pollution are similar to the levels recorded previous to 2014, when the Chinese premier declared a war on pollution due to the health dangers posed by rising air pollution levels.

However, since 2015, levels of air pollution have risen once again. This pollution has had hard hitting effects on urban areas, especially the Chinese capital Beijing, and has caused widespread disruption to the lives of Chinese citizens and economy of the country.

The air pollution leads to the cities becoming hotter than ever. Urban Heat Island effect, which refers to buildings absorbing the sun’s heat well, is exacerbated by the smog. In fact, a car in the heat can reach temperatures of 114 degrees Fahrenheit after just 20 minutes, making travelling on hot days nearly unbearable for any living creature. In order to decrease the heated condition of China, it is essential to decrease the amount of smog covering the cities.

What Has the Chinese Government Done?

The Chinese government has taken limited action in an attempt to minimize the air pollution being created in the country. This includes the Atmospheric Pollution Prevention Plan, which acknowledged the danger posed by air pollution levels and aimed to reduce coal usage in urban areas like Beijing.

However, this is not representative of the main action the government has taken. Primarily, the Chinese government has focused on individual areas and attempting to reduce local pollution levels through efficient coal burning and banning the burning of waste materials, especially on farms. These solutions, while effective on a short-term basis, are not all that is needed, though.

Investment in renewables can reduce China's dependence on coal for power generation

Investment in renewables can reduce China’s dependence on coal for power generation

China needs to reduce its overall usage of coal produced energy, which currently stands at 64 percent of total energy consumption. While this has already been happening in China, the further introduction of renewable energy could be of great help to China’s pollution levels.

How Could Renewable Energy Help?

Many people believe renewable energy to be a small affair, something undertaken by the Western world in a vain attempt to reduce our collective guilt concerning climate change and wastage levels. This is simply not the case. Renewable energy is a $120 billion industry that receives investment and application across the world. This includes solar energy, waste-to-energy technology, wind energy, hydroelectric energy and many more attempts to reduce overall energy usage.

Through investment in renewable energy, China could reduce its dependence on coal and increase the efficiency of its energy production and economy. Smog is directly created by China’s use of coal for its energy production, and by investing in other renewable means, China can simultaneously improve its health situation.

In fact, the obviously positive nature of investment in renewable energy can be clearly seen through the Chinese government’s already existing plans to further incorporate it into the economy. In the five-year plan announced in 2016, the Chinese government explicitly stated it would decrease air pollution levels through investment in wind, solar and biomass energy production technologies.

While the plans additionally included investment in making the coal industry more efficient and reducing emissions on an industrial and commercial level, clearly renewable energy is believed to be a valid alternative energy source.

Overall, it is clear that renewable energy can certainly help with China’s serious smog problem. Whether this should be in tangent with further investment in the coal industry or necessitate the end of widespread coal usage in China is still a question for debate.

About the Author

Emily Folk is freelance writer and blogger on topics of renewable energy and conservation. To get her latest posts, check out her blog Conservation Folks, or follow her on Twitter.

Renewables Market in MENA

mena-renewablesMENA region has an attractive market for renewables due to abundant availability of solar and wind resources. According to a recent IRENA report, the region is anticipating renewable energy investment of $35 billion per year by 2020. Recently, the MENA region has received some of the lowest renewable energy prices awarded globally for solar PV and wind energy.

Regional Developments

Among MENA countries, Morocco has emerged as a role model for the entire region. The government’s target of 2GW of solar and 2GW of wind power by 2020 is progressing smoothly with the commissioning of Nour-1 Solar project. Jordan and Egypt are also making steady progress in renewable energy sector.

As far as GCC is concerned, the UAE has also shown serious commitment to develop solar energy. The 100MW Shams CSP plant has been operational since 2014 in Abu Dhabi while 13MW Phase I of Dubai’s solar park was completed in 2013. In Saudi Arabia, the newly launched Vision 2030 document has put forward a strong regulatory and investment framework to develop Saudi clean energy sector which should catalyse renewable energy development in the country.

Renewables – A boon for MENA

Renewable energy has multiple advantages for MENA in the form of energy security, improved air quality, reduced GHG emissions, employment opportunities, apart from augmenting water and food security.

The business case for renewable energy proliferation in MENA is strengthened by plentiful availability of natural energy resources and tumbling solar PV technology costs which are leading to record low renewable power generation costs. The recent auction for the Mohammed Bin Rashid Al Maktoum Solar Park 2 in Dubai yielded prices as low as 5.85 US cents per kWh which is one of the lowest worldwide.

Impact of Falling Costs

The falling costs will have a significant positive impact in the developing world where tens of millions of people still lack access to cheap and reliable supply of energy. Reducing costs will help MENA, especially GCC, to meet its target of steady transition towards renewable energy and thus reducing dependence on fossil fuels for power generation and seawater desalination.

The slump in renewable energy tariffs will also encourage utility companies in emerging markets to include more renewable energy in transmission and meet the targets set by respective countries. However, it should also be noted that there have been several instances where the actual renewable energy production failed to take place because of low bids.

Emerging Trends

Off-grid renewable energy technologies have tremendous potential to popularize clean energy among remote and marginalized communities across the world. Access to clean, reliable and relatively cheap energy from renewable resources, especially solar power, will usher in a new era in developing countries. Off-grid (or standalone) renewable power systems are already making a meaningful difference in the lives of millions of people across the developing world.

In recent years, Morocco has made remarkably swift progress in renewable energy sector.

In recent years, Morocco has made remarkably swift progress in renewable energy sector.

Advancements in battery energy storage have pushed this particular sector into media as well as public spotlight. With big industry names like Tesla and Nissan leading from the front, energy storage technologies are expected to make great contribution in transition to green grid powered by intermittent energy sources like solar PV, CSP, wind and biomass.

Concentrated solar power (CSP) has the potential to transform seawater desalination industry, one of the largest energy consumers in the Middle East. CSP offers an attractive option to power industrial-scale desalination plants that require both high temperature fluids and electricity.  CSP can provide stable energy supply for continuous operation of desalination plants, based on thermal or membrane processes. Leading CSP technology companies are already taking a keen interest in Middle East CSP market and rapid developments are expected in the coming years.

Key Hurdles to Overcome

Lack of strong regulatory framework, low renewable energy tariffs and weak off-take mechanisms are some of the issues confronting renewable energy projects in MENA. Regulatory framework in the GCC is in early stages and marred by heavy subsidy for oil and gas. The largest barrier to growth of solar sector in MENA has been the lack of renewable energy policy framework, legislations, institutional support, feed-in-tariffs and grid access.

The power sector in MENA is, by and large, dominated by state utilities which discourage entrepreneurs and Independent Power Producers (IPPs) to enter the local markets. Lack of open and transparent market conditions in MENA are acting as deterrent for investors, technology companies and project developers.

Among regional countries, Jordan and Morocco have the most advanced legal infrastructure in place to support renewable energy projects, followed by Saudi Arabia and the UAE.

Tips for New Entrants

MENA solar market is complex due to different electricity market structure and myriad challenges in each country. Different countries have different motivations for renewable energy. Solar companies who want to foray in MENA market must give special attention to land access, grid access, transparent licensing schemes, high-quality meteorological data, creditworthy customers, long-term off-take contracts, soiling of PV panels and related issues.

Tips to Choose the Budget-Friendly System of Energy

Newly arrived at your new home, the first thing is to make sure that you are going to pay the bill for the area that is in your use. That’s why the first day in your new home is advisable to take the meter reading. Good time to introduce yourself to the president of the community … or whoever wants to keep the keys of the accounting room. This advice also applies to gas, water, and other supplies whether it’s new construction or used housing, you should take a meter reading.  Look for iselect energy website! When moving, the first thing is to take note of the different counters (light, water, gas) in order to take responsibility only for what you are going to consume.

When moving, the first thing is to take note of the different counters (light, water, gas) in order to take responsibility only for what you are going to consume.

Your freedom of choice is sacred

It is very important that you know that you are always entitled to choose your electric company freely. You decide you send.  You have bought a house, or you are renting, this is a right of every consumer to choose the budget-friendly ways for electricity consumption. It is so legitimate that you are interested in changing or continuing with the electric company that you are hired.

What can you choose?

 The company that will send your electricity bill, that is, the electric energy trader.

What can you not choose?

The company that is responsible for providing the energy to your home, that is, the distributor. You do not choose it because you have to choose the one that corresponds to your place of residence.

When you arrive at a new house, it may happen that:

  1. The light is discharged, and both the power and the rate seem appropriate:

If so, and if you want to continue being a client of the same marketer, all you have to do is change the owner of the contract. This procedure is simple, fast and free.

  1. The light is discharged, but the power seems excessive or insufficient

You will have to make a change of power. This procedure costs money, although lowering the power can save a lot on your bill.

  1. The electricity connection is registered, but you want to change the tariff

When you arrive, you can “inherit” a contract with a certain company and a certain rate. If what you find does not convince you, you are free to change your electric energy provider. It is your choice, which service you want to choose for your home.

  1. The light has no connection to the electricity network

If your supply point has not been used for more than 3 years, this procedure costs money. The contract of registration is processed with the distributor, but it is the distributor that installs the meter and activates the supply. For this reason, the payment of this procedure will be made to the distributor in the first invoice.

The payment procedure for the efficient electricity providers is very simple and easy for the consumers. You can pay your bills and others online via credit and debit card.

Moving Grate Incineration: Preferred WTE Technology

Incineration is the most popular waste treatment method that transforms waste materials into useful energy. The incineration process converts waste into ash, flue gas, and heat. The type of thermal WTE technology most commonly used worldwide for municipal solid waste is the moving grate incineration. These moving grate incinerators are even sometimes referred to as as the Municipal Solid Waste Incinerators (MSWIs). As of August 2013, of more than 1000 of 1200 Waste-to-Energy plants (among 40 different countries) there is no pre-treatment of the MSW before it is combusted using a moving grate. The hot combustion gases are commonly used in boilers to create steam that can be utilized for electricity production. The excess energy that can’t be used for electricity can possibly be used for industrial purposes, such as desalination or district heating/cooling

Benefits of Moving Grate

The moving grate incineration technology is lenient in that it doesn’t need prior MSW sorting or shredding and can accommodate large quantities and variations of MSW composition and calorific value. With over 100 years of operation experience, the moving grate incineration system has a long track record of operation for mixed MSW treatment. Between 2003 and 2011, it was reported that at least 106 moving grate incineration plants were built worldwide for MSW treatment. Currently, it is the main thermal treatment used for mixed MSW.

Compared to other thermal treatment technologies, the unit capacity and plant capacity of the moving grate incineration system is the highest, ranging from 10 to 920 tpd and 20 to 4,300 tpd. This system is able to operate 8,000 hours per year with one scheduled stop for inspection and maintenance of a duration of roughly one month. Today, the moving grate incineration system is the only treatment type which has been proven to be capable of treating over 3,000 tpd of mixed MSW without requiring any pretreatment steps. Being composed of six lines of furnace, one of the world’s largest moving grate incineration plants has a capacity of 4,300 tpd and was installed in Singapore by Mitsubishi in 2000

Working Principle

Moving-grate incineration requires that the grate be able to move the waste from the combustion chamber to allow for an effective and complete combustion. A single incineration plant is able to process thirty-five metric tons of waste per hour of treatment.

The MSW for a moving grate incinerator does not require pretreatment. For this reason, it is easier to process large variations and quantities. Most of these incineration plants have hydraulic feeders to feed as-received MSW to the combustion chamber (a moving grate that burns the material), a boiler to recover heat, an air pollution control system to clean toxins in the flus gas, and discharge units for the fly ash. The air or water-cooled moving grate is the central piece of the process and is made of special alloys that resist the high temperature and avoid erosion and corrosion.

Working principle of a grate incinerator

The waste is first dried on the grate and then burnt at a high temperature (850 to 950 degrees C) accompanied with a supply of air. With a crane, the waste itself is emptied into an opening in the grate. The waste then moves towards the ash pit and it is then treated with water, cleaning the ash out. Air then flows through the waste, cooling the grate. Sometimes grates can also be cooled with water instead. Air gets blown through the boiler once more (but faster this time) to complete the burning of the flue gases to improve the mixing and excess of oxygen.

Suitability for Developing Nations

For lower income and developing countries with overflowing landfills, the moving grate incinerator seems suitable and efficient. Moving grate incineration is the most efficient technology for a large-scale mixed MSW treatment because it is the only thermal technology that has been able to treat over 3,000 tons of mixed MSW per day. It also seems to be considerably cheaper than conventional technologies.

Compared to other types of Waste-to-Energy technologies, this type of system also shows the highest ability to handle variation of MSW characteristics. As for the other incineration technologies like gasification and pyrolysis technologies, these are either limited in small-scale, limited in material for industrial/hazardous waste treatment, requiring preprocessing of mixed MSW before feeding, which make them not suitable for large-scale mixed MSW treatment.

Conclusion

For the reduction of significant waste volume, treatment using a moving grate incinerator with energy recovery is the most commonly used form of waste-to-energy (WTE) technology. The moving grate’s ability to treat significant volumes of waste efficiently, while not requiring pre-treatment or sorting is a major advantage that makes this suitable for developing countries. This technology could provide many other benefits to such nations. Implementing moving grate incinerators is most suitable for developing nations because not only will it reduce waste volume, but it would also reduce the demand for landfills, and could recover energy for electricity.

References

 “A Rapidly Emerging WTE Technology: Circulating Fluid Bed Combustion”. Huang, Qunxing, Yong Chi1, and Nickolas J. Themelis. Proceedings of International Thermal Treatment Technologies (IT3), San Antonio, TX, October 2013. Columbia University. Available: http://www.seas.columbia.edu/earth/wtert/sofos/Rapid_Emerging_Tech_CFB.pdf accessed on 29 March 2016.
“Incineration.” Waste Management Resources. Waste Management Resources. Available: http://www.wrfound.org.uk/articles/incineration.html accessed on 29 March 2016.
Kamuk, Bettina, and Jørgen Haukohl. ISWA Guidelines: Waste to Energy in Low and Middle Income Countries. Rep. International Solid Waste Association, 2013. Print.
“Municipal Solid Waste Management and Waste-to-Energy in the United States, China and Japan.” Themelis, Nickolas J., and Charles Mussche. 2nd International Academic Symposium on Enhanced Landfill Mining, Houthalen and Helchteren, Belgium, 4-16 October 2013.  Enhanced Landfill Mining. Columbia University. Available: http://elfm.eu/Uploads/ELFM/FILE_73D907E9-8225-4B93-91F8-10F71F59B793.PDF accessed on 29 March 2016.
“Review of MSW Thermal Treatment Tecnologies.” Lai, K.C.K., I.M.C. Lo, and T.T.Z. Liu. Proceedings of the International Conference on Solid Waste 2011- Moving Towards Sustainable Resource Management, Hong Kong SAR, P.R. China, 2 – 6 May 2011. Hong Kong SAR, P.R. China. 2011. 317-321. Available: http://www.iswa.org/uploads/tx_iswaknowledgebase/10_Thermal_Technology.pdf. accessed on 14 April 2016.
UN-HABITAT, 2010. Collection of Municipal Solid Waste in Developing Countries. United Nations Human Settlements Programme (UN-HABITAT), Nairobi. Available:
http://www.eawag.ch/fileadmin/Domain1/Abteilungen/sandec/E-Learning/Moocs/Solid_Waste/W1/Collection_MSW_2010.pdf.
World Bank, 2012. What a Waste: A Global Review of Solid Waste Management. Urban Development Series Knowledge Papers. Available: http://documents.worldbank.org/curated/en/2012/03/16537275/waste-global-review-solid-wastemanagement. accessed on 14 April 2016.

Description of a Biogas Power Plant

A biogas plant is a decentralized energy system, which can lead to self-sufficiency in heat and power needs, and at the same time reduces environmental pollution. The components of a modern biogas (or anaerobic digestion) plant include: manure collection, anaerobic digester, effluent treatment, biogas storage, and biogas use/electricity generating equipment.

Working of a Biogas Plant

The fresh animal manure is stored in a collection tank before its processing to the homogenization tank which is equipped with a mixer to facilitate homogenization of the waste stream. The uniformly mixed waste is passed through a macerator to obtain uniform particle size of 5-10 mm and pumped into suitable-capacity anaerobic digesters where stabilization of organic waste takes place.

In anaerobic digestion, organic material is converted to biogas by a series of bacteria groups into methane and carbon dioxide. The majority of commercially operating digesters are plug flow and complete-mix reactors operating at mesophilic temperatures. The type of digester used varies with the consistency and solids content of the feedstock, with capital investment factors and with the primary purpose of digestion.

Biogas Cleanup

Biogas contain significant amount of hydrogen sulfide (H2S) gas which needs to be stripped off due to its highly corrosive nature. The removal of H2S takes place in a biological desulphurization unit in which a limited quantity of air is added to biogas in the presence of specialized aerobic bacteria which oxidizes H2S into elemental sulfur.

Utilization of Biogas

Biogas is dried and vented into a CHP unit to a generator to produce electricity and heat. The size of the CHP system depends on the amount of biogas produced daily.

Treatment of Digestate

The digested substrate is passed through screw presses for dewatering and then subjected to solar drying and conditioning to give high-quality organic fertilizer.  The press water is treated in an effluent treatment plant based on activated sludge process which consists of an aeration tank and a secondary clarifier. The treated wastewater is recycled to meet in-house plant requirements.

Monitoring of Environmental Parameters

A chemical laboratory is necessary to continuously monitor important environmental parameters such as BOD, COD, VFA, pH, ammonia, C:N ratio at different locations for efficient and proper functioning of the process.

Control System

The continuous monitoring of the biogas plant is achieved by using a remote control system such as Supervisory Control and Data Acquisition (SCADA) system. This remote system facilitates immediate feedback and adjustment, which can result in energy savings.