Normally on “Mining and Refining,” we concentrate on the actual material that’s mined and refined. We’ve covered everything from copper to tungsten, with side trips to more unusual materials like sulfur and helium. The idea is to shine a spotlight on the geology and chemistry of the material while concentrating on the different technologies needed to exploit often very rare or low-concentration deposits and bring them to market.
This time, though, we’re going to take a look at not a specific resource, but a technique: fracking. Hydraulic fracturing is very much in the news lately for its potential environmental impact, both in terms of its immediate effects on groundwater quality and for its perpetuation of our dependence on fossil fuels. Understanding what fracking is and how it works is key to being able to assess the risks and benefits of its use. There’s also the fact that like many engineering processes carried out on a massive scale, there are a lot of interesting things going on with fracking that are worth exploring in their own right. Continue reading “Mining And Refining: Fracking”→
Climate change promises to cause untold damage across the world if greenhouse gas emissions continue at current levels for much longer. Despite the wealth of evidence indicating impending doom, governments have done what humans do best, and procrastinated on solving the issue.
However, legislatures around the world are beginning to snap into action. With transportation being a major contributor to greenhouse gas emissions — 16% of the global total in 2016 — measures are being taken to reduce this figure. With electric cars now a viable reality, many governments are planning to ban the sale of internal combustion vehicles in the coming decades.
Diesel is a fuel that has had a mixed history, with varying levels of take-up by consumers around the world. In the world of transport, diesel engines have offered better fuel economy and torque than comparable gasoline engines. Particularly popular in Europe, diesel established a strong consumer base in both small commuter cars as well as heavy vehicles such as trucks and buses.
Despite this, the tide is turning, and for the average motorist, diesel’s days may be numbered. Why is this the case, and what are the potential alternatives vying for diesel’s crown?
Plenty of Pros, but Plenty of Cons
Diesel remains a fuel with a varied uptake around the world. It has enjoyed great popularity in Europe in small commuter cars.
Diesel is a hydrocarbon fuel with several advantages over gasoline. Its lack of volatility makes it workable to use in a compression-ignition mode, and diesel engines can be run with lean fuel-air ratios. It also has a higher volumetric energy density than gasoline, and thanks to low volatility, diesel engines can run at significantly higher compression ratios without risking detonation. These benefits allow diesel engines to produce significantly more torque than similarly sized gasoline engines, and they can offer fuel economy gains in excess of 15%.
Unfortunately, diesel also comes with its fair share of drawbacks. Diesel engines are typically poor when it comes to power to weight ratio, as their high compression ratio and torque output demands heavier materials in their construction. The major bugbear of the diesel engine, however, is its emissions. Despite greater fuel efficiency, carbon dioxide output from a diesel engine is often far worse than that of a comparable gas motor. Additionally, their lean-burning nature leads to production of high levels of oxides of nitrogen (NOx), which have major negative environmental effects. There’s also the problem of particulate pollution, which is responsible for respiratory harm in humans. Diesel automobiles rank significantly worse than gasoline vehicles in all these areas. It’s begun to cause figurative headaches for the industry, and literal headaches for the public. Continue reading “The Future Of Diesel Is On Shaky Ground”→
