The reactor is at the heart of a four-stage test plant that generates fuel from water, CO 2 , and electricity. Those ions travel through an oxygen-permeable solid membrane to the anode, where they give up electrons and combine to produce O 2. The mix of CO and H 2 , known as synthesis gas, then moves to a third reactor, which assembles them into more complex hydrocarbons. Sunfire's test plant now makes about 10 liters of fuel per day. The company is already scaling up the technology and plans to open its first commercial plant, in Norway, next year.
The setup will be part of a larger plant that will use 20 megawatts of hydropower to produce tons of transportation fuel per year, enough to supply 13, cars. Another advance could also boost efficiency: using industrial waste as the source of electrons needed to split off CO from CO 2.
And as a bonus, when glycerol loses electrons, it produces a combination of formic acid and lactic acid, two common industrial compounds used as preservatives and in cleaning products and cosmetics. The problems are twofold: First, every time new bonds are forged, some energy is lost. And generating more-complex hydrocarbons inevitably means making more side products.
That outcome forces producers to separate their desired compound, at extra cost. But innovations are starting to help there, too, including better catalysts.
The Chemistry of Biofuels
They achieved that efficiency by pressing one electrode directly onto the membrane, thereby eliminating a fluid-filled gap that was sapping energy and was causing the device to break down quickly. One class of complex molecules that could prove easier to make with electricity is carbon nanotubes.
Those long, hollow, strawlike molecules—prized for their strength and electronic capabilities—are commonly made through chemical vapor deposition: In a heated quartz tube, cobalt and iron catalysts strip away carbon atoms from pumped-in acetylene gas and add them to growing nanotubes that take seed on the metal particles. Licht's setup starts with molten lithium carbonate spiked with metal catalysts.
An electric current strips carbon atoms from the lithium carbonate and adds heat that sustains the reaction. The catalysts pick up the carbons and insert them into growing nanotubes. The process is Because it uses waste CO 2 , Licht notes it is carbon negative: Making each ton of carbon nanotubes uses 4 tons of CO 2. The nanotubes can then be mixed into cement to create a high-strength composite that sequesters the carbon, keeping it from oxidizing and returning to the atmosphere.
Biofuels are not a green alternative to fossil fuels | Environment | The Guardian
The tubes can also be mixed with metals such as aluminum, titanium, and stainless steel to strengthen them. Nate Lewis, a chemical engineer at Caltech, says the transition will be slow. One major hurdle, he notes, is that renewables are intermittent, meaning chemical plants relying on them will be inefficient. Economists capture the idea with a measure called the capacity factor, a ratio of a plant's output over time compared with what's theoretically possible.
The upshot, Lewis notes, is that any plant powered by renewables would take longer to make a profit, making investors reluctant to back such projects. Plants driven by renewables could stay online longer if they drew on multiple power sources or had a steadier power supply thanks to batteries or another form of energy storage, Kammen notes. But those solutions can add cost, Lewis says. Producing enough renewable electricity to remake the chemical industry is also a challenge.
Perhaps the most likely outlook for industrial chemistry is a gradual greening.
While fossil fuels consist only of carbon and hydrogen atoms, or hydrocarbons, biofuels contain oxygen atoms, and their chemical composition may include acids, alcohols and esters. Biobutanol is derived from biomass or produced by fermentation using organisms found in ruminant animals and soils. The basic composition of butanol consists of C carbon , H hydrogen and O oxygen.
The chemical formula for the butanol molecule is C4H10O. Biobutanol provides more energy than ethanol and can be blended with gasoline to help reduce greenhouse gases. Any car that runs on gasoline can run on a biobutanol blend. Derived from vegetable oils and animal fats, biodiesel molecules are esters of long-chain fatty acids containing single chains of 12 to 24 carbon atoms. The esters contain an alcohol and a carboxylic acid. Slow growth eg trees for wood fuels, fast to burn! Biodiesel is another biofuel derived from plant material. Biodiesel can be made from vegetable oils and animal fat or waste cooking oil which contain glycerol esters of long—chain fatty acids.
Vegetable oils are suitable for diesel fuel and release lots of energy on combustion just like petrol or conventional diesel. Biodiesel has similar physical and chemical properties to ordinary diesel from crude oil and burns in conventional diesel engines. The simple word equation for processing vegetable oil into biodiesel fuel is Biodiesel is readily biodegradable , so less harmful to the environment if spilled compared to hydrocarbon oils which take much longer to break down.
Existing diesel engines don't need converting. Cons — disadvantages of using biodiesel Its relatively expensive to make small scale production compared to the petrochemical industry based on crude oil. There won't be enough to replace diesel from crude oil. Farmers especially in third world countries may switch from essential food production to producing plant oils to make biodiesel, thereby increasing food prices and maybe creating food shortages.
Ethanol is one of the more recent 'alternative fuels' to traditional fossil fuels like coal, gas and oil. If an efficient source of hydrogen production could be found, this could be another fuel. Chemistry of alcohols - ethanol b Ethanol is easily stored and distributed as a liquid fuel. Advantages a The biogas can be burned like any other fuel to produce heat. Not as convenient as petrol Large storage volume. Not as convenient as petrol Not as convenient as petrol but more dense than hydrogen or methane gases Hygroscopic, absorbs water, causes corrosion Hygroscopic, absorbs water, causes corrosion NO, too inconvenient, polluting and back to the steam engine!
- Energy demands.
- Frontiers for Young Minds?
- Are biofuels worse than fossil fuels?.
- (PDF) Chemistry of Fossil Fuels and Biofuels | Riccardo Pappalardo - mutegiroxoby.ml.
- Microelectronic Systems: Circuits, Systems and Applications!
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Email doc b: chem hotmail. FUEL all renewable in theory. Advantages of the biofuel, the 'pros'.
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Disadvantages of the biofuel, the 'cons'. Disadvantages a Slow rate of mass production b Requires large areas of agricultural land or cleared woodland AND farmers may switch from growing food crops — increasing food prices and possible causing food shortages in third world countries. Advantages a Endless supply of water b Water is the only product of burning hydrogen, so its very clean non—polluting combustion.
See also use of hydrogen in fuels cells. Disadvantages a Efficient large scale technology not yet developed to produce hydrogen on a large scale eg from electrolysis using solar power electricity — photovoltaic power system, wind turbines or hydroelectric power. Microorganisms can be used to break down organic waste under anaerobic conditions to produce biogas, which is mainly the hydrocarbon methane gas, CH 4.
Disadvantages a At the moment biogas cannot be produced on a huge scale. Fuel Consideration Factor. Hydrogen H 2. Methane Natural Gas CH 4. Coal Mainly Carbon but contains some Sulphur. Suitability for road transport. Large storage volume.