Inventions in Clean Tech for Industry

Industry Clean Tech in 2012

Clean tech (or green tech if you prefer) innovations directed to industry continue in 2012. Two of these are summarized in this post.

Environmentally Friendly Coolants

Environmentally friendly doesn’t get much more friendly than graphite – pure, crystalline carbon – carbon is the basis of life.

Patent US 8,192,643 addresses “Graphite microfluids”. Granted to Ruiting Zheng of Beijing, China and two co-inventors, and assigned to the Massachusetts Institute of Technology in Cambridge, MA on June 5, 2012, the invention is very simply described by Claim 1:

A microfluid, comprising:
a hydrophobic fluid;
and a plurality of amphiphilic graphite particles having an average maximum cross-sectional dimension of between about 500 nanometers and about 10 microns, wherein the graphite particles form a stable suspension within the fluid, and the graphite particles are in the substantial absence of a surfactant.

500 nanometers to 10 microns is about 8–25% of the diameter of the thinnest human hair, which is 40 microns = 40 millionths of a meter = 0.0016 inches.
From the patent’s Background section:

Many industrial and commercial systems such as, for example, power plants, automobile engines, and microelectronics systems require efficient heat transfer to achieve optimal operation. Conventional methods for enhancing heat transfer include incorporating extended surfaces (e.g., fins) into the heat exchanger system and increasing the flow rate of the heat transfer fluid. However, the use of these traditional methods is insufficient to achieve adequate heat transfer in many instances. Recent research has been done on high thermal conductivity fluids. Such fluids can be made, for example, by suspending materials with relatively high thermal conductivities in fluid with a lower thermal conductivity. In addition to providing adequate heat transfer in high-performance applications, the use of high thermal conductivity fluids can be used to reduce the size of heat exchanger units in applications with lower heat transfer demands. 

The production of high thermal conductivity fluids can pose challenges. For example, in many instances, it is difficult to produce a stable suspension of high thermal conductivity material in a suitable heat exchange fluid. In addition, some materials, such as many nanoscale materials, do not produce sufficient increases in thermal conductivity when they are suspended in low thermal conductivity fluids. Finally, many materials used to produce high thermal conductivity fluids are prohibitively expensive for everyday use.

The USPTO groups this invention with others that provide heat-exchange, low-freezing or pour point, or high boiling compositions with organic components. The first US patent of this type was issued in 1866 (US 58,755) for the “Use of Hydrocarbon Liquids for Transmitting Heat” in railroad cars and other public conveyances and buildings. Inventor William C. Baker (…interesting – the long-time head of the Chesapeake Bay Foundation, a well-known environmentalist and organization here in the Mid-Atlantic region, is William C. (Will) Baker) experimented “chiefly with kerosene-oil, as it [was] a cheap and convenient fluid, but it [was] obvious that any other suitable [oil] properly prepared may be substituted therefor…” As with many patents that break new technological ground, Baker’s 1866 patent included a single very simple claim:

The employment of hydrocarbon liquids to circulate in heating surfaces, as and for the purposes set forth.

At the present stage of clean/green tech, there really isn’t much new under the sun. Different methods, processes, and materials perhaps, but not too many completely new, this-has-never-been-thought-of-before ideas.

Aluminum Recycling – Not Just For Cans

Aluminum recycling is particularly effective in large part because it requires only about 5% of the energy used to manufacture new aluminum. According to the US Geological Survey’s Mineral Resources Program,

[i]n 2011, aluminum recovered from purchased scrap in the United States was about 3.0 million tons, of which about 54% came from new (manufacturing) scrap and 46% from old scrap (discarded aluminum products). Aluminum recovered from old scrap was equivalent to about 36% of apparent consumption.

How long have you been recycling aluminum? If you are part of The Greatest Generation, maybe you’ve been saving and recycling aluminum since the 1940s? If you are early boomers, since the introduction of the all-aluminum beverage can in the mid–1960s? Maybe after the first couple of Earth Days in the early 1970s? Perhaps after the enactment of a deposit fee with refund for bottles and cans in numerous states? How about when your locality instituted specified recycling dumpsters for those living in rural areas, or curbside recycling for those of you living in cities or the ‘burbs?

Aluminum recycling plants were first established in the US in Chicago, IL and Cleveland, OH in 1904. Curbside recycling began in Baltimore, MD in 1874. Oregon passed the first “bottle bill” in 1972.

Most of the aluminum recycled by consumers is in the form of empty beverage cans. This may soon change with industrial commercialization of patent US 8,211,378, “Reactor for separating aluminium from multi-layer film materials”. The invention of Youngchul Lee of Seoul, South Korea was issued on July 3, 2012 and assigned to the Korea Institute of Industrial Technology.

Lee’s invention is a chemical reactor for separating an aluminum layer from multi-layer film wastes. The reactor comprises a cylindrical casing which is filled with a solution to dissolve aluminum layers of the multi-layer film wastes pulverized into a predetermined size. A partition divides an inner portion of the casing into a reactor tub in which the solution reacts with the aluminum layer, and a separator tub is provided to decompose the pulverized multi-layer film wastes.

Lee views his reactor as being especially useful in separating aluminum used in multi-layer films used for packing foods (for the purposes of moisture resistance, aesthetic appearance, etc.) or for packing materials. In addition,

defective goods may be produced during the bonding processes or the printing process, and the defective goods are wasted. In addition, a stamping foil, which is formed by attaching dye or pigment, binder, an aluminum layer and release agent to a polyester film, is used for transferring patterns and aesthetic colors to raw fabric. When the stamping foil has been used once, the stamping foil is disposed without being reused due to the remaining adhesive, dye or pigment, binder, aluminum layer and release agent. The disposed multi-layer film materials are partially reused without special treatments. However, since the multi-layer film materials contain various components mixed in predetermined ratios and have the aluminum layer, the multi-layer film materials represent poor physical properties. For this reason, the multi-layer film materials are merely reused in producing low-value products. In addition, most multi-layer film wastes and the stamping foils are disposed without reuse through incineration or burial methods, so that the environmental pollution problem caused by toxic substances created during incineration becomes serious.

Thus, the reactor may find use for recycling aluminum/plastic films now discarded by consumers, and by the manufacturers of such films as a way of recycling defective materials and reducing toxins emitted by incineration of the plastic portion of the film.

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