05 February 2008

Combined Heat and Power Biomass, More Biofuels

Combined Heat and Power (CHP) is a highly efficient form of power production. One such plant in Denmark that utilises biomass in its fuel mix meets the heating demands of 200,000 homes and the electrical demands of 1.3 million homes.
Avedore 2, inaugurated in 2002, made the green switch successfully and is now a set of superlatives: it is the world's largest biomass power plant as well as the cleanest and most efficient cogeneration power station. It meets the heating demands of 200,000 households and supplies electricity to over 1.3 million homes (Denmark has a population of 5.47 million). The green plant covers more than 20% of Eastern Denmark's needs - the most densely populated region of the country - and supplies 570MW of heat to Greater Copenhagen's district heating system. The combined heat and power efficiency comes in at a whopping 95%.
A new type of external combustion engine that will burn biomass-based syngas, is developing 10 1MW generators for the Florida market.
The companies' plans are to power these industrial generators using a glycerol-based synthesis gas produced through Florida Syngas' proprietary plasma gasification process called GlidArc. Glycerol (glycerin), the waste product of the biodiesel industry, yields a hydrogen-rich, carbon neutral gas with its only waste products being hot water and useable heat.....Cyclone engine technology is a new type of external combustion engine but relies on established technologies, such as those used in gas turbines, diesel engines, and steam engines. The engine is based on the Schoell cycle, a cross between a Rankine, Diesel and Carnot cycle engine (schematic, click to enlarge). Its main characteristic is that it will burn any combustible fuel, including biomass and municipal waste. Advent Power Systems claims the engine has other advantages:

* Clean burning – Provides complete combustion and a very clean exhaust
* Efficiencies comparable to diesels, when all required subsystems are included
* High horsepower to weight ratios – about a 2.5 to 1 advantage over full diesel systems.
* Low noise, vibration, and infrared signatures.
* Large range of sizes possible – from 1 KW up to over 1 Megawatt.
* Facilitates conversion to a range of synthetic fuels, including biomass.
* Provides an ideal power source for hybrid and conventional vehicles.
* Does not require a radiator, water pump, oil pump, complex fuel injection, or catalytic converter, reducing cost, weight, space and increasing reliability.___Source

I am particularly curious to learn more about the external combustion engine mechanism, that will be driving the 1 MW generators. The global glycerol glut from world biodiesel production should provide inexpensive fuel, and the ability to convert to biomass fuels, there should be no "peak fuel" scenario for these facilities.

Finally, China and Brazil are said to be collaborating on development of bio-ethanol from a newly discovered type of cassava--a sweet cassava mutant.
China currently cultivates around half a million hectares of cassava, of which 200,000 are destined for ethanol production. The People's Republic chose cassava as one of its future biofuels crops, because it is considered to be an industrial plant, and not a food crop. According to Wenquan Wang, researcher at CATAS, cassava has gained importance because of its low environmental footprint and because it has a well established industrial presence. "For 30 years, cassava was a staple for many Chinese people, later it became a crop for animal feed, and nowadays 60% of the entire harvest is destined for the industrial production of starch, 20% goes to ethanol and the remainder is turned into pig feed."

However, China's cassava ethanol initiative is mainly based on starch rich varieties. Together with Brazil it is now looking at introducing the sweet varieties instead, which demand less costly and complicated conversion steps.

I wonder how the sweet cassava alcohol yield will compare with the yield from sugar cane? Regardless, it has to be a much higher yield than from maize.

Labels: , , , ,

Bookmark and Share


Post a Comment

“During times of universal deceit, telling the truth becomes a revolutionary act” _George Orwell

<< Home

Newer Posts Older Posts