Moving Grate Incineration: The Most Common 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.

There are more than 1500 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.

moving-grate_incinerator

Benefits of Moving Grate Incineration

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 2020, it was reported that at least 200 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 common waste-to-energy 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.
“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.

How Much Energy Do Bitcoin and Other Cryptocurrencies Consume?

With its value skyrocketing in recent years, Bitcoin is a hot topic right now. But the value of a Bitcoin is not the only thing that is growing. In fact, Cambridge University research suggests that Bitcoin uses more electricity on a yearly basis than entire countries. Mining for cryptocurrency uses a lot of power, and requires heavy computer calculations to verify cryptocurrency transactions. According to the researchers, this consumes over 120 terawatt-hours (TWh) annually, and this power use is unlikely to fall unless the value of Bitcoin drops.

Is Bitcoin Bad for the Environment?

Many believe that cryptocurrency is the currency of the future, but is it bad for the environment? Will Bitcoin and other cryptocurrencies undo the hard work that has been put in around the world so far to improve the condition and health of the planet? According to some critics, Tesla’s decision to make heavy investments in Bitcoin undermines the environmental image displayed by the electric car company.

cryptocurrency-energy-consumption

The rising price of Bitcoin offers even more incentive to miners to run even more machines and consume more power. As the value of Bitcoin increases, so does the energy consumption that is used to mine it, according to researchers at the Cambridge Centre for Alternative Finance.

Exactly How Much Energy Does Bitcoin Consume?

How much energy is consumed due to the increasing popularity of cryptocurrency trading? According to the online tool developed by the Cambridge researchers, Bitcoin’s electricity consumption is currently ranked above several countries including Argentina, the Netherlands, and the United Arab Emirates. It’s using a very similar amount of energy to the amount that Norway uses on a yearly basis.

In the UK, the energy that Bitcoin uses could be used to power all the electric kettles in the country for almost three decades. However, in comparison, the amount of electricity that is consumed on a yearly basis by devices that are left switched on but inactive in homes around the US could power the entire Bitcoin network for a full year.

How is Bitcoin Mined?

Mining Bitcoin requires often specialized computers which are connected to the cryptocurrency network. They are used to verify transactions by people who sell or purchase Bitcoin. As part of the process, Bitcoin miners are required to solve puzzles that are not integral to providing verification, but ensure that there is a hurdle to cross to ensure that the global record of all Bitcoin transactions is not edited fraudulently. As a reward for completing these, Bitcoin miners will occasionally receive small amounts of Bitcoin.

crytpocurrency-mining

Higher prices have increased the value of these rewards, and fueled wider interest in buying and selling crypto via increasingly diverse methods beyond using exchanges. At the same time, some miners have expanded their networks to consist of multiple computers. Some will even set up entire warehouses of computers that are there for mining Bitcoin alone. Since the computers are working to solve the puzzles on a constant basis, this uses a huge amount of electricity.

While Bitcoin is becoming more and more popular as an alternative currency and investment option around the world, how efficient is it really?

How Mechanical and Electrical Engineers Can Help in Renewable Energy Projects Design?

Over the last decade, the renewable energy industry has witnessed tremendous global growth, and mechanical engineers have made a significant contribution in ensuring the transition to pure energy and other sustainable practices around the globe.

Over the last decade, the renewable energy industry has witnessed tremendous global growth, and mechanical engineers have made a significant contribution in ensuring the transition to pure energy and other sustainable practices around the globe.

The same can be said about the role of electrical engineers in this industry. Nowadays, humans can observe the movement of small businesses and startups toward carbon-free solutions, for instance, solar, wind, biomass, geothermal, and hydroelectric power in action in all their projects.

Using full benefits of renewable energy sources demands advanced technology in manufacturing, preserving, and supplying electricity. That is what makes the technical expertise of electrical engineers an essential resource at small businesses or startups striving to integrate eco-friendly practices.

In case your business/startup is connected with designing renewable energy projects, the first thing you should do is to check some renewable energy market analysis so that you can develop your strategy. Then, it would be brilliant to find 3D modeling services to make your renewable energy project come true and hire relevant types of engineers who will work on your project.

Now, let’s take a glimpse at several ways how mechanical and electrical engineers can help you in that. We will start with mechanical engineers.

electrical-engineering

Mechanical Engineers in Renewable Energy Projects

Small business and startup owners should consider this type of engineer as a must for designing renewable energy solutions! Why?

A wide range of the essential skills that mechanical engineers experience in their graduate programs possess many useful practices for renewable energy engineering. Profound knowledge in fluid mechanics, heat transfer, and thermodynamics, for instance, is a clue to designing the wind power eco solution. The same expertise is also necessary when improving cooling systems, developing hydropower infrastructure, and creating new energy preservation technology, for example, solar fuel or thermochemical batteries for long-term energy storage.

Small business and startup owners should hire mechanical engineers because they practically can be involved in every step of renewable energy generation/distribution. From designing approaches that minimize the cost of silicon production for solar panels to developing optimized ways to build wind farms, this kind of engineer is significant to improving the renewable energy infrastructure. Below, you can see several essential duties of mechanical engineers in designing renewable energy solutions:

  • Rationalizing a certain renewable energy technology for it to get more financially beneficial to develop relevant infrastructure;
  • Explore various materials and their interrelation for further implementation in renewable energy leading to innovative systems/technologies design for producing and supplying eco power;
  • Provide small business and startup owners with consultations regarding renewable energy projects, including delivering the best ways to achieve sustainability goals: determining technology needs and methods to build and invest in renewable energy infrastructure;
  • Multiple integrations of all types of renewable energy technologies.

How Electrical Engineers Solve Renewable Energy Challenges?

When it comes to the contribution of electrical engineers to sustainability-based energy projects, it is the following.

The wind turbines and solar panels that produce pure energy are often located in areas far from municipalities. To experience all bonuses of environmentally friendly electricity, mankind requires the infrastructure to distribute such energy into homes.

Designing a renewable energy project and faced the above-mentioned challenge? Here, electrical engineers are your option!

As a rule, electrical engineers engaged in renewable energy transmission address the following issues:

  • Modernizing and expanding high-voltage distribution lines, selecting appropriate areas for construction to reduce environmental influence;
  • Identifying the finest strategies to transform renewable energy into electricity safely and effectively;
  • Precisely predicting the requirement for eco power and enabling facilities to possess the storage capacity to satisfy those requirements;
  • Securely managing the power flows from production facilities via the grid;
  • Designing innovative control platforms to check how the grid behaves and to react to troubles as they happen.

In case your startup is connected with microgrids, electrical engineers can come in handy. For those who are not on the topic, let’s clarify the thing.

solar-microgrid

Various platforms that involve microgrids make it possible to get more effective energy distribution than ordinary grids, resulting in eco power systems that are less wasteful as well as more financially beneficial.

Besides, some microgrids suggest an eco-friendly alternative by using a renewable energy source, for instance, wind power, biomass, or solar power. With permanent technological development, such microgrids can become central to implementing energy even greener!

It requires creative problem-solving as well as innovative technical knowledge to support in revolutionizing eco-energy production, distribution, and consumption. Electrical engineers understand the principles which are on the background of the latest achievements in the energy transformation, power platforms, and power grids. So, they can potentially design a win-win solution for your business in the renewable energy industry.

How to Realistically Lower Your Utility Bills

Homebuilders are starting to pay more attention to sustainability in the construction process since they’re more mindful of eco-conscious buyers and the rising cost of utilities. For example, the use of cellular glass insulation is becoming more common in the building industry.

What about existing and especially older homes, however? How can you realistically lower your utility bills and be more sustainably minded?

The following are things to keep in mind.

Tips to Realistically Lower Your Energy Bills

After-the-Fact Insulation and General Efficiency

While you might not be able to re-insulate your entire house, there are still things you can do to make it more insulated overall.

First and foremost, the winter season is here, and you should go through your entire house to make sure there aren’t any air leaks in your windows and doors. You can use caulking and weatherproofing strips to combat them. You can also install a window insulation kit.

If you have thick, lined curtains, this will keep heat in your house. If you don’t want to buy new curtains, you can add material as a liner, like fleece. During the day, keep your curtains open in the winter, so the sun will warm them up. Then, as the sun is setting, close them to seal the heat in.

Some people use so-called door snakes, which are essentially just something made from materials like old socks that you put at the bottom of your door to block the cold air.

If you have a chimney, plug it in while it’s not in use. In one study, household heating bills were 30% higher when a house had a missing or broken fireplace damper. If your flue doesn’t properly seal, you’re potentially losing a lot of heat through the chimney. You can use a chimney balloon to seal it.

If you have an attic, take a look around. Heat can escape through the attic. You can add foil sheets to the rafters in the roof so that the heat is reflected and goes back into your living space.

Check the seals on your appliances, just like you do for your windows and doors because you want your cold air staying where it belongs.

Improve your heating and cooling efficiency by fixing leaky ductwork, and if you’re sleeping or not at home, set your thermostat back anywhere from 10 to 15 degrees. A programmable thermostat will do the work for you.

Regularly change your air filters because when an air conditioner or furnace has a dirty filter, it makes running your appliances more expensive. It also makes your home dustier. Make sure you’re changing your filters every 60-90 days.

clogged filter of AC

Water

The hot water you use in your home is likely your second-largest power-related expense, based on data from the Energy Department.

Taking shorter showers is simple enough, but there are other things you can do here as well. Replace your showerhead with one that’s efficient, and don’t wash clothes in hot water.

Adjust the temperature on your water heater since the default is typically 140 degrees. If you lower it to 120 degrees, you can reduce the costs of heating your water by as much as 10%. If you’re going out of town, turn the heater to the lowest possible setting.

Lighting and Power

Your electronics and lights make up around 11% of your energy usage.

The easiest fix here is swapping out your old lightbulbs for LED bulbs with an Energy Star label.

Dimmer switch installation isn’t necessarily as easy, but it can save you a lot. Dimmers let you adjust brightness as you need, so you’re saving electricity, and you’re also in control of the ambiance of your room.

Some electronics don’t ever actually power off. They might be in standby mode, so over time, they’re using a continuous trickle of electricity. You can use a smart power strip, which will cut the current if these devices aren’t being used.

You’ll often hear these devices referred to as vampire appliances. A vampire appliance can be anything that doesn’t need to be plugged in all the time yet is.

You can get a home energy monitor that will tell you more about the use of electricity in your home via a mobile app. These devices plug into your electrical panel. You can buy them online, and then it will show you how plugging in or unplugging different devices could impact how much wattage you’re using.

reduce electricity bill

Only run your appliances, like your dishwasher, washing machine, and dryer, when they’re full. No matter how full they are, they’re using the same amount of energy, so wait until you can do a complete load.

Get An Energy Audit

If you’ve never done so, with the likely soaring costs of energy this winter, it could be a good time to consult a professional for an energy audit.

During an energy audit, the person conducting it may do blower door tests, which will check for drafts. They can also use infrared cameras and do other types of inspections to assess the house, the features, and your habits.

These take between one and five hours to complete and usually cost around $400 on average, although they can be more depending on where you live and how big your house is.

Some energy companies offer audits for free or at a discount to their customers, so before you pay, talk to your provider.

The Department of Energy says that if you make efficiency upgrades, it can save you between 5-30% on your bills.

Finally, look at the size of the machines you’re using for both work and entertainment. More people are doing more things at home than ever before, but this could be negatively affecting your energy usage.

Your desktop computer, for example, is going to use more energy than a laptop. Laptops are more efficient overall, and you can unplug them more easily when you’re not using them.

HPE0-J69 dumps

Video game consoles are another example. They’re a lot less efficient than a smaller streaming device. Some people use video game consoles to stream TV shows and apps, but you should only use these consoles for games. Get a dedicated streaming device for TV because a console will use as much as 20 times more energy.

4 Ways To Pay Your Electricity Bill Effortlessly

Utilities like water and power can end up costing nearly as much as your rent or house payment in a bad month. Unfortunately, you can’t cut off your water service to save money the way you could cut the cable. Here are a few tips to tame your utility bills and make it easier to pay your electricity bill with ease.

1. Clean Up

Cleaning the coils on your refrigerator helps it work more efficiently. Cleaning the coils on your air conditioner can do the same, but your AC uses far more power than your fridge. Remove any debris from the air intakes, whether it is leaving piles up by the AC or the air vent to your furnace. Rinse the air filters for your room air filters, the air conditioner, and your dehumidifier.

2. Turn It Off

While the appliances that are sleeping may use less energy than when on, the reality is that they use almost as much power in standby as they do when active. The solution is to turn things off. Unless your game station is downloading updates, unplug it to save power. Turn off the TV instead of letting it sit in standby, or worse, use it as background noise.

When gadgets are fully charged, disconnect them from the charging station and turn off the charging station. If you can’t stand to turn off your computer, turn off the monitor instead. Turn off lights when they aren’t in use, and consider when you can utilize natural light instead. Don’t let appliances idly run while you’re busy. Get the clothes out of the dryer instead of letting it run every five minutes to prevent clothes from wrinkling.

Turn off the oven when you’re done with it. The same might be said for your pool pump or air filters. Does it need to be running? If not, consider turning it off for a while. Always aim to improve your habits and to acquire energy-saver appliances. Also, consider that you are still allowed to hire a better energy provider in case the current one is not the best fit regarding your lifestyle. For instance, there are plenty of options when it comes to the most suitable electric companies in dallas.

3. Track Energy Usage

You can get apps that report energy usage in your home. These apps can tap into your smart meter and tell you which appliances are consuming the most energy. If you can’t cut back on energy usage, you could get advice on how to shift energy usage in order to reduce your electric bill.

For example, running the clothes dryer at night may allow you to get utility discounts. One of the advantages of hydroelectric energy is that despite facing daily and seasonal variations, utility companies will still provide discounts when the demand for power is lower.

Set up the dishwasher to run a heavy load when you go to bed, and the cost per kilowatt maybe a third of what you’d pay if it ran during the day. You may also find that the AC is running heavily during the hottest part of the day.

Could you alter the thermal profile of your home so that it uses less energy while keeping you comfortable, such as not trying to keep the house at 65 when you’re at work? If you cannot get the house comfortable without the AC running full blast all the time, you may need to have the air conditioner repaired or replaced with a more powerful unit.

4. Check for Leaks

If you’ve ever heard the joke that you’re not heating the neighborhood, recognize that there is an element of truth to that joke. When you leave the door open while you’re bringing in groceries or getting the mail, you’re wasting the energy used to heat or cool that air. Gaps in your window frame and window stripping cost you the same way.

Leaks in your hot water heater waste both water and the energy used to heat it. Look for water leaks when you suspect them, too. Not only does this damage the structure of your home and wastewater, but damp insulation has a fraction of the thermal value of dry insulation. This is how a water leak could be contributing to your higher energy bills.

There are a number of things you can do to reduce your energy bills and water bills without radically changing your lifestyle. Then you’ll be able to save the Earth’s resources and money at the same time. It is truly a win-win for everyone.

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 key components of a modern biogas power (or anaerobic digestion) plant include: manure collection, anaerobic digester, effluent treatment, biogas storage, and biogas use/electricity generating equipment.

anaerobic_digestion_plant

Working of a Biogas Plant

The fresh organic waste 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 digester 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.

Generating Electricity from Municipal Solid Waste

We live in a throwaway society that accumulates vast quantities of waste every day. While this comes with pressing challenges, there are also opportunities for professionals including electrical engineers to process at least some of the waste to produce much-needed renewable energy.

According to the U.S. Energy Information Administration (EIA), in 2018 a total of 68 U.S. power plants generated around 14 billion kilowatt-hours of electricity from 29.5 million tons of combustible municipal solid waste (MSW). Biomass, which comes from plants and animals and is a source of renewable energy, was responsible for more than half (about 51%) of the electricity generated from waste. It also accounted for about 64% of the weight of the MSW used. The rest of the waste used was from other combustible materials including synthetic materials made from petroleum and plastics. Glass and metal are generally not noncombustible.

WTE_Plant_Belgium

Waste-to-Energy is now widely accepted as a part of sustainable waste management strategy.

Municipal Solid Waste in the U.S.

Burning MSW is not only a sustainable way to produce electricity, it also reduces the volume of waste that would inevitably end up in landfills. Instead, the EIA estimates that burning MSW effectively reduces waste volumes by about 87%.

But, while more than 268 million tons of MSW are generated in the United States every year, in 2017, only 12.7% of it was burned to recover energy. More than half (52.1%) went to landfill, about a quarter (25.1%) was recycled, and the rest (10.1%) was used to generate compost.

According to a U.S. Environmental Protection Agency (EPA) fact sheet on sustainable materials management published in November 2019, the total MSW generated in 2017 by material, comprised:

  • Paper and paperboard, primarily containers and packaging 25%
  • Food 15.2% (see below)
  • Plastics 13.2% (19.2% of the total materials that ended up in landfill were plastics)
  • Yard trimmings 13.1% (most of this type of waste is composted)
  • Rubber, leather and textiles 9.7%
  • Metals 9.4%
  • Wood 6.7%
  • Glass 4.2%
  • Other 3.5%

Indicating tremendous human waste in its worst form, 22% of the material that ended up in landfill was classified as food. Trashed food was also the product category with the highest landfill rate, at an alarming 75.3%. Nearly a quarter (22%) of materials that were combusted with energy recovery were food, and overall, food was also the highest product category to recover energy, with a rate of 18.4%.

The total MSW combusted to generate energy was made up of the following materials:

  • Food 22%
  • Plastics 16.4%
  • Rubber, leather, and textiles 16.1%
  • Paper and paperboard 13.2%
  • Wood 8.4%
  • Metals 8.6%
  • Yard trimmings 6.2%
  • Glass 4.3%
  • Other 4.3%

Generating Electricity from MSW

There are a variety of technologies for generating electricity from municipal solid waste, but in the US the most common system involves mass burning of MSW in a large incinerator that has a boiler that produces steam, and a generator that produces electricity. Another entails processing MSW into fuel pellets for use in smaller power plants.

Waste materials destined to be processed to generate electricity

Generating electricity in mass-burn WTE plants is remarkably straightforward and follows seven basic steps:

  1. The MSW is dumped out of garbage trucks into a large pit.
  2. A crane with a giant claw attachment is used to grab the waste and dump it into a combustion chamber.
  3. The waste, which now becomes the fuel, starts to burn, releasing heat.
  4. The heat that is released turns water in the boiler into high-pressure steam.
  5. The steam turns the turbine generator’s blades and produces electricity.
  6. The mass-burn plant incorporates an control system to prevent air pollution by removing pollutants from the combustion gas before it is released through a smoke-stack.
  7. Ash is inevitably produced in the boiler and the air pollution control system, and this has to be removed before another load of waste can be burned.

While the volumes burned as fuel in different plants vary, for every 100 pounds of MSW produced in the US, potentially, more than 85 pounds could be burned to generate electricity.

Of course, the USA isn’t the only country that uses waste-to-energy plants to generate electricity from MSW. And in fact, when compared to a lot of other countries, the percentage of MSW burned with energy recovery in the U.S. is minimal. At least nine countries are named by the EIA as bigger producers of electricity from municipal waste. In Japan and some European countries, for instance, there are fewer energy resources and not much open space available for landfills. So generating electricity from MSW is an obvious opportunity.

The four leading nations identified by the EIA as burning the most MSW with energy recovery are:

  • Japan 68%
  • Norway 54%
  • Switzerland 48%
  • France 35%
  • The United Kingdom 34%

One thing’s for certain, the percentages are all set to continue increases globally as the move towards sustainability gains momentum. And U.S. percentages are going to increase too.

Use of PKS in Circulating Fluidized Bed Power Plants

Palm kernel shells are widely used in fluidized bed combustion-based power plants in Japan and South Korea. The key advantages of fluidized bed combustion (FBC) technology are higher fuel flexibility, high efficiency and relatively low combustion temperature. FBC technology, which can either be bubbling fluidized bed (BFB) or circulating fluidized bed (CFB), is suitable for plant capacities above 20 MW. Palm kernel shells (PKS) is more suitable for CFB-based power plant because its size is less than 4 cm.

palm-kernel-shell-uses

Palm kernel shells is an abundant biomass resource in Southeast Asia

With relatively low operating temperature of around 650 – 900 oC, the ash problem can be minimized. Certain biomass fuels have high ash levels and ash-forming materials that can potentially damage these generating units.

In addition, the fuel cleanliness factor is also important as certain impurities, such as metals, can block the air pores on the perforated plate of FBC unit. It is to be noted that air, especially oxygen, is essential for the biomass combustion process and for keeping the fuel bed in fluidized condition.

The requirements for clean fuel must be met by the provider or seller of the biomass fuel. Usually the purchasers require an acceptable amount of impurities (contaminants) of less than 1%. Cleaning of PKS is done by sifting (screening) which may either be manual or mechanical.

In addition to PKS, biomass pellets from agricultural wastes or agro-industrial wastes, such as EFB pellets which have a high ash content and low melting point, can also be used in CFB-based power plants. More specifically, CFBs are more efficient and emit less flue gas than BFBs.

The disadvantages of CFB power plant is the high concentration of the flue gas which demands high degree of efficiency of the dust precipitator and the boiler cleaning system. In addition, the bed material is lost alongwith ash and has to be replenished regularly.

A large-scale biomass power plant in Japan

The commonly used bed materials are silica sand and dolomite. To reduce operating costs, bed material is usually reused after separation of ash. The technique is that the ash mixture is separated from a large size material with fine particles and silica sand in a water classifier. Next the fine material is returned to the bed.

Currently power plants in Japan that have an efficiency of more than 41% are only based on ultra supercritical pulverized coal. Modification of power plants can also be done to improve the efficiency, which require more investments. The existing CFB power plants are driving up the need to use more and more PKS in Japan for biomass power generation without significant plant modifications.

5 Solar Panel Facts You Might Not Know

Over the last decade, it seems that the cost of electricity has risen in most areas. This is one of the reasons why so many people are getting solar energy systems installed in their homes. Due to its rise in popularity, we have seen prices for solar panels and other equipment needed to make your home more eco-friendly decrease.

Because solar energy is still fairly new technology, many people still know very little about the industry. To help you out, we have compiled a few interesting facts about solar panels which you might find interesting.

As the industry grows, you will probably be hearing much more about solar panels and the benefits of using this eco-friendly method to provide energy for your home. Below are solar panel FAQs to remember:

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1. The First Solar Panel Cell was Discovered in 1941

Although it seems like solar panels have only been around for the last few decades, the world’s first solar panel cell was invented by Russell Ohl in 1941. Shortly after the invention of the first solar panel cell was invented, Bell Laboratories came up with the world’s first commercial panel in 1954.

Although it seems we are still at the stone age of solar power, photovoltaic (the conversion of light into electricity) was discovered by French scientist Alexandre Edmond Becquerel in 1839.

2. In the Long Run, Solar Power can help Save you Money

Although the initial cost of installing a solar system in your home might be frightening, the overall running cost of the system can save you a lot of money. Although prices of installation and equipment are becoming more affordable, it still is expensive for the average household.

However, try to keep in mind that you won’t ever have to pay to heat or cool down your house again (assuming your solar panels power system can provide enough energy throughout the year for your home). The average household spends $1,300 annually on their electricity bill.

Throughout the world, it seems more and more governments are trying to encourage homeowners and business owners to invest in solar panels. Lots of governments have offered people incentives and tax breaks in the hope that the number of households using this eco-friendly method will increase. In some states in America, people who purchase solar panels are eligible for a 30% tax break. Also, some states allow those who own solar power to sell their excess energy, so they can make some profit from their system.

3. A Communal Effort

Community solar systems are becoming more common these days. Instead of just having an individual solar system in your home, more communities are investing in community solar systems instead.

Over the last 15 years or so, instead of each household having individual systems installed, whole communities are getting together and investing in a system that will provide energy for the entire community. If you are considering making your home more eco-friendly, why not speak to others in your community to see if everybody on the block is interested in getting a communal solar system installed instead?

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4. The Industry is Growing Extremely Fast

Between 2018 and 2010, the number of households and businesses having solar power installed in their buildings grew 23 times in the United States. Solar power is not only becoming more appealing to homeowners in the United States, but it seems like people all over the world are deciding to go green and install solar power systems into their homes.

China uses more solar power than any other country on the planet. The Chinese government has been offering the residents of the country plenty of incentives that has resulted in many people installing a solar power system in their home.

If you are thinking about installing a solar power system inside your home, check out Solar Panels Network USA for more information. If you are still on the fence about joining the solar power movement, ask them for advice.

5. Maintaining a Solar Power System

Maintaining your solar power system tends to be fairly cheap too. In fact, once the system is fully installed there is actually very little maintenance needed. Apart from cleaning the panels now and again, and making sure that it’s getting sunlight and not shaded, it should work smoothly. You may have to trim some trees at times but that’s about it.

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Most solar panels have been installed on a tilted roof, so when the rain hits it will clean any dust and dirt from the panel so you won’t have to clean it too often.

Most solar power system suppliers offer 25 year warranty, but it is not too uncommon to see a quality solar power system last for 40 years. If your system does manage to last for that length of time, you can imagine how much money you will save on electricity.

Combined Heat and Power Systems in the Biomass Industry

Combined heat and power systems in the biomass industry means the simultaneous generation of multiple forms of useful energy (usually mechanical and thermal) from biomass resources in a single, integrated system. In a conventional electricity generation systems, about 35% of the energy potential contained in the fuel is converted on average into electricity, whilst the rest is lost as waste heat. CHP systems use both electricity and heat and therefore can achieve an efficiency of up to 90%.

CHP technologies are well suited for sustainable development projects because they are socio-economically attractive and technologically mature and reliable. In developing countries, cogeneration can easily be integrated in many industries, especially agriculture and food processing, taking advantage of the biomass residues of the production process. This has the dual benefits of lowering fuel costs and solving waste disposal issues.

CHP systems consist of a number of individual components—prime mover (heat engine), generator, heat recovery, and electrical interconnection—configured into an integrated whole. Prime movers for CHP units include reciprocating engines, combustion or gas turbines, steam turbines, microturbines, and fuel cells.

A typical CHP system provides:

  • Distributed generation of electrical and/or mechanical power.
  • Waste-heat recovery for heating, cooling, or process applications.
  • Seamless system integration for a variety of technologies, thermal applications, and fuel types.

The success of any biomass-fuelled CHP plant is heavily dependent on the availability of a suitable biomass feedstock freely available in urban and rural areas.

Rural Resources Urban Resources
Forest residues Urban wood waste
Wood wastes Municipal solid wastes
Crop residues Agro-industrial wastes
Energy crops Food processing residues
Animal manure Sewage

Technology Options

Reciprocating or internal combustion engines (ICEs) are among the most widely used prime movers to power small electricity generators. Advantages include large variations in the size range available, fast start-up, good efficiencies under partial load efficiency, reliability, and long life.

Steam turbines are the most commonly employed prime movers for large power outputs. Steam at lower pressure is extracted from the steam turbine and used directly or is converted to other forms of thermal energy. System efficiencies can vary between 15 and 35% depending on the steam parameters.

Co-firing 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. Biomass can typically provide between 3 and 15 percent of the input energy into the power plant. Most forms of biomass are suitable for co-firing.

Steam engines are also proven technology but suited mainly for constant speed operation in industrial environments. Steam engines are available in different sizes ranging from a few kW to more than 1 MWe.

A gas turbine system requires landfill gas, biogas, or a biomass gasifier to produce the gas for the turbine. This biogas must be carefully filtered of particulate matter to avoid damaging the blades of the gas turbine.

Stirling engines utilize any source of heat provided that it is of sufficiently high temperature. A wide variety of heat sources can be used but the Stirling engine is particularly well-suited to biomass fuels. Stirling engines are available in the 0.5 to 150 kWe range and a number of companies are working on its further development.

A micro-turbine recovers part of the exhaust heat for preheating the combustion air and hence increases overall efficiency to around 20-30%. Several competing manufacturers are developing units in the 25-250kWe range. Advantages of micro-turbines include compact and light weight design, a fairly wide size range due to modularity, and low noise levels.

Fuel cells are electrochemical devices in which hydrogen-rich fuel produces heat and power. Hydrogen can be produced from a wide range of renewable and non-renewable sources. A future high temperature fuel cell burning biomass might be able to achieve greater than 50% efficiency.