The production of waste, especially with many countries emerging into powerful economies, has become a problem of such dimensions that something definite has to be done.Many new technologies are being developed to process, recycle and reuse waste, some combining waste treatment processes in the same plant to produce a variety of useful products such as electrical energy, diesel, heat, carbon black and other recyclable materials. Latest estimates show that there are 431 waste-to-energy (WTE) plants in Europe and 89 in the United States (2004). The U.S. recycles 14 percent of its trash in WTE plants.
by Javier Herrero y Sáenz de Cabezón, CEO of Bauhaus Capital Partners. Read his blog, Renewable Energy Investment, Acquisitions and Business Development or connect with him on Linkedin
Waste comes in many forms, municipal solid waste, biomass waste, industrial wastes etc. and in a consumer based society was considered a bothersome collateral which you either dumped into a landfill, incinerated or cleaned up to minimum requirements and injected into the nearest water body.
The production of waste, especially with many countries emerging into powerful economies, has become a problem of such dimensions that something definite has to be done. Waste is causing unbearable pollution and earthquakes and mudslides uncover landfills under housing developments and seepage contaminates water and agricultural land and gases generated cause foul odors and health problems. Worldwide indiscriminate incineration is also contributing substantially to the climate change.
Alas – desperation is the mother of invention, but it seems that as industry and governments have discovered that in solving the problem there is much money to be made the race is on to conquer a new and lucrative market of waste to energy. Many new technologies are being developed, some combining waste treatment processes in the same plant to produce a variety of useful products such as electrical energy, diesel, heat, carbon black and other recyclable materials. The feedstock is equally varied and the different technologies are combined in a modular fashion depending on the type of waste that is available at each particular location to get the most out of it and at the same. [See Why You Need to Pay Attention to Bio Natural Gas and Bio-domes Offer a Sustainable Waste Water Solution]
Municipal Solid Waste
Waste-to-energy (WTE) is the process of creating energy in the form of electricity or heat from the conversion of a waste resource. WTE is a form of energy recovery. Most WTE processes produce electricity directly through combustion (incineration), but a gasification process produces a combustible fuel gas consisting mostly of methane, carbon monoxide and hydrogen.
Latest estimates show that there were 431 WTE plants in Europe and 89 in the United States (2004). The U.S. recycles 14 percent of its trash in WTE plants. Denmark, on the other hand, reuses 54 percent.
Gasification WTE plants work very much like natural gas fired power plants. The difference is the fuel. Waste-to-energy plants use syngas made from garbage—not natural gas— to fire a gas turbine. The same steps are used to make electricity in a waste-to-energy plant as in a natural gas fired power plant, this method is known as “combined cycle”:
• The fuel is heated, releasing gas.
• The gas is combusted in a gas turbine
• The turbine turns a generator to produce electricity
• The waste heat from the turbine turns water into steam.
• The high-pressure steam turns the blades of a steam turbine which turns a generator to produce electricity.
• A utility company sends the electricity along power lines to homes, schools, and businesses.
The principle of thermolysis is based on the decomposition of organic matter into solid residue and combustible gas by using heat at 600°C in the absence of oxygen. After treatment, the volume of sludge is reduced by at least 10.
Unlike incineration or gasification, thermolysis optimises energy production. The gas produced, which can be recycled to treat new sludge, allows the plant to meet its own energy requirements. Moreover, there is no oxidation reaction (combustion) of the matter, only decomposition, enabling a notable reduction in fumes and harmful volatile elements. Pollutants such as heavy metals, when present, are trapped then stabilised. They can then be stored without causing a nuisance for the environment.
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The Pyrolyzer system uses a slow pyrolysis method developed by the German company KUG GmbH. It is an innovative state of the art pyrolysis process for the gasification of carbon based waste materials to produce fuel gas. The fuel gas (PyroGasTM) reaches a calorific value of 5 to 14 KWh/m3 or 500 to 1400 BTU/ft³ depending on type of feedstock. PyroGasTM made with the KUG process can be used interchangeably with natural gas or for highly efficient, extremely low-emission power generation in gas engines, gas turbines, and combined cycle systems. Alternatively, it can also be used as feedstock for liquid transportation fuels production or separated into Hydrogen and Liquid Natural Gas (LNG).
Characteristics of the KUG Thermolysis Process
- Gas production: 820 m3 per metric ton feedstock material.
- Heating value: ~500 – 1400 BTU/ft³, depending on the feedstock.
- Very low emissions (50% below German Environmental Air Emission Standards).
- Adjustable to various feedstocks, including biomass, wood waste, MSW, rubber and plastics.
Innovations of the KUG GmbH Process
- Multistage bi-directional gasification reaction is controlled kinetically on a catalytic carbon bed.
- Improved heat transfer by indirect heating using the carrier effect.
- Reaction occurs in the absence of oxygen avoiding Dioxins and Furans.
- Bi-directional flow of the materials avoiding short cuts in the gas stream ensuring complete gasification.
- Multistage gas treatments using newly patented technologies.
- Tars treated internally by additional integrated cracking reactors
- Vitrified slag with minimized residues.
Advantages of the KUG Pyrolysis Process
• Fuel gas with quality standards comparable to natural gas in purity and BTU value.
• Very low emissions.
• High thermal efficiency (70 – 85%).
• Efficient separation and processing of liquid aromatic oils and tars with conversion into additional fuel gas.
The integrated Waste / Bio-Mass to energy plant
Bio Mass can contribute to a huge extend for covering the fuel and energy demand. Each country has a treasure of not-used sources of bio mass, such as waste from rice peeling, sugar cane or leftovers from oil mills, straw, sawdust, wood waste. Statistically only 50% of the produced food reaches the table of the consumer. The rest is sorted out during the supply chain by not meeting quality standards, exceeding legal shelf times or other reasons. These materials can be turned into fuel and energy without having any impact on the alimentation of the population.
Catalytic Pressure-less Depolarization
Recyclable waste is sorted out and sent into the specific recycling processes. For the left over passive and non-toxic ashes – in lack of local production that could use those – a final deposit is created following international standards.
Green Power Inc (GPI) claims to have developed a method of inexpensively converting biomass and household waste into high grade diesel fuel, a process they call “NanoDiesel” that could go a long way toward solving the world’s energy and waste problems at the same time, without upsetting the CO2 balance.
In March of 2008, GPI completed their first production prototype that is said to be capable of processing 100 tons of municipal and other waste per day in a low heat and low pressure, proprietary catalytic system, converting the feedstock into high grade fuel, including diesel, kerosene, and fuel oil; as well as electricity and an asphalt component.
The preparation of incoming waste stream includes chopping, extraction of metals, glass, and sand, so that approximately 2/3 of the feedstock is able to be run through the unit to produce fuel and electricity.
The key to the system is the catalyst (trade secret) which is said to be made from environmentally benign components.
GPI says a 100 ton/day facility will employ approximately 5 people per shift, in three shifts per day. Methane generated in the process is used to run a generator to power the facility, with 1 Megawatt excess available for distribution.
They claim that the raw costs of producing the diesel is about $0.60/gallon. Covering capitalization, maintenance, marketing, decommissioning and other costs will place the actual cost much higher, but still competitive with fossil-based fuel.
The conversion of input waste to fuel output is said to be around 25-30% efficient so that one ton of input waste will produce around 120 gallons (~3.8 barrels) of diesel. Materials that can be converted to diesel fuel through this process include plastics (including PVCs), rubber, waste oils, agricultural wastes (food and animal waste) and wood. The diesel produced is not biodiesel, but purportedly a pure hydrocarbon diesel, equivalent to what comes out of the oil fields.
Other products that can be produced in a combined plant are:
• Neutral ash for industrial / construction / agriculture
• Recyclable materials (metals and glass)
• Synthetic Diesel
• Electrical Power
• Fertilizer and manure for agriculture
• Water for irrigation
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