Green Building and Living

Go green slogan has been buzzing all around us for year. We read, suggest various tips how to go green like using energy star appliances, switching to CFL/LED etc. but we hardly hear and talk the which electricity to shop? I mean here we hardly think about the source of electricity, whether the electricity is clean or renewable?
Having said that, few basic questions pop-up regarding cleaner/greener source of electricity. What are the cleaner source of electricity available? Are they available in our area?
Common clean energy resources available in U.S. are wind, hydro, PV, landfill gas, biogas. And to find out who are the providers in your area or are they expensive? You just need to visit website of U.S. department of energy and then the sub section buying green power. For an example in Texas clean power can be purchased from the Green Mountain Energy Company one of the partners of Shop Electricity Rates Texas.
The next question comes how to shop clean electricity?
You don’t get electricity directly from clean/green electricity provider. The electricity is fed to common power grid and then delivers to your home. There are number of electricity providers who sell both fossil fuel based electricity and also clean electricity, one of them is Shop Electricity Rates Texas.

According to Dr. Adrian Vance, algal-butanol has potential to contribute in America’s fuel requirements and carbon dioxide sequestration to fight green house effect and global warming, algae are fastest growing plants and in presence of sunlight and CO2 they can double their mass with in 12 hrs.

According to him algae farming and butanol production is very simple process, algae is cultivated in algae farm tank in presence of CO2 and sunlight and the mass is then flow down to fermentation tank in presence of butanol producing bacteria. Accorgding to Dr. Adrian, experiments can be carried out using 1 foot deep, 8 feet wide and 200 feet long plastic trough for algae farming, CO2 can be supplied through tubing in form of bubbles and the culture kept agitated using motor driven screws and at the end of the day half of the top of the culture will be ready for fermentation and can be transferred to fermentation vessel.

Algae culture then will be mixed with Clostridium tyrobutyricum and Clostridium acetobutylicum bacteria in fermentation vessel where temperature can be maintained by sun light or by heat exchangers. After several days of fermentation the culture will be cooled to zero degree Celsius and butanol will be separated out from the water.

After my previous two post I got comments asking what are methods of production of bio-butanol, so I thought to cover various process of biobutanol production starting from upcoming. Economical production of bio-butanol in commercial scale is little far, all the processes available for bio-butanol have one or another hitches.

Fuel derived from food sources are loosing their shine due to food vs fuel reality, non-food feed stock such as biomass are catching interest lately. Syngas (synthesis gas, which is mixture of hydrogen and carbon monoxide) can be derived from gasification of biomass can be catalytically converted to organic fuels like ethanol, butanol and other higher alcohols.

The whole process of biomass to biobutanol can be divided in three basic steps, first is gasification of biomass to syngas and its cleaning and polishing for removal of particulate, tar, acid gases and some other impurities like ammonia. The second step is alcohols synthesis using appropriate catalyst and third step is separation of alcohols.

To best of my knowledge this process of bio-butanol process is at its nascent stage only and groups which are working on this are Syntec Biofuel and Diesel Brewing.

As I mentioned in previous post butanol is not too far to be seen as a fuel, this chemical has properties which make this fuel as a versatile fuel, clean energy source, has a potential to reduce formation of green house gases like carbon di oxide,pollutants like sulfur di oxide and global warming. In gasoline blend butanol works as a fuel, oxygenate and also additive for octane rating improvement, benefits of butanol in diesel fuel I’ve written in previous post. Here are summary of companies involved in biobutanol process development.

BP-Dupont:
Any discussion on bio-butanol fuel can not go on/off without mentioning BP-Dupont partnership, butanol has caught huge attention lately as a biofuel after an interest shown by this partnership. There process is based on fermentation route of producing butanol using sugar from variety of feed stocks. BP-Dupont have recently announced commencement of commercialization of butanol with the name Butamax Advanced Biofuels. Butamax is closely working with Kingston research Limited, KRL is a consulting a bio-butanol technology demonstration plant in UK, which is planned to be operational in 2010 and the first commercial plant is expected to be operational by 2013.
Cobalt Biofuels:
California based biofuel company has proprietary technologies in microbial physiology, strain development, fermentation. They believe their local, non food based feed stock, continuous fermentation and patented vapor compression distillation separation system significantly reduces energy and production cost. Cobalt biofuels use the bacteria clostrium to break down components of plant matter including cellulosic, hemicellulosic and starch and produce butanol, ethanol, and acetone (ABE). Cobalt Biofuels has raised capital from a high profile list of venture funds, including Pinnacle Ventures, Vantage Point Venture Partners, Malaysian Life Sciences Capital Funds, Life Science Partners.
Butyl Fuel, LLC:
BFL has developed a biobutanol fermentation process which has significantly reduces the production cost compared to conventional fermentation process. This patented technology is would e able to produce 1.3 to 1.9 times more butanol per bushel of corn compared to conventional ABE process. And estimated production cost is $1.2/ gallon which is less than ethanol’s cost $1.28/gallon and petrobased butanol’s cost $.35/gallon, and according to BFL the cost can be further brought down by using waste feed stock.
Gevo:
Gevo is a Colorado based company in to next generation fuel, engaged in production of isobutanol using fermentation route. The project is led by Dr. Liao from ULCA using genetically modified microbe for higher butanol tolerance and yield. Gevo is also involved in process engineering to enhance productivity and cut down separation cost. Gevo is backed by venture capitalist like Khosla group, Total and Virgin Green funds.

Green Biologics:
UK-based company has developed their own thermophillic bacteria for rapid enzymatically release of fermentable sugar from biomass, this bacteria strains can also digest hemicellulose (5-carbon sugar) feed stocks. GBL’s using genetic engineering has developed a strain to produce high yields of butanol and can tolerate close to 4% butanol concentration. Recently, GBL has announced signing agreement between GBL and Laxmi Organics, India for construction of commercial demonstrator for bio-butanol.
Syntec Biofuel:
Syntec is a Canada based renewable energy company working on processes of biomass to alcohols (B2A). Right now thry are working on development of catalyst for conversion of cellulosic biomass to pure isobutanol using thermochemical process. Syntec biofuel is focusing on utilizing wide range of biomass like, MSW, forestry and agriculture waste as a feedstock.

Few other player in bio-butanol race are RITE-HONDA, TetraVitae Bioscience, Diesel Brewing, Syngas Biofuels Energy, Inc

A lot has been talked and discussed about biobutanol as a potential fuel for gasoline blend and its advantages, but very less has been researched, discussed and talked about butanol as a DIESEL fuel. I have been working on “butanol as a fuel ” for more than two years I have studied, researched and analysed butanol’s properties as a gasoline blend fuel as well as diesel blend fuel. More I went in to depth of butanol more I started liking to see butanol as a full blown fuel in either way, the simple reason is blending of butanol improves various shortcomings of gasoline and diesel.

Diesel automobiles are the backbone of the transportation across the globe, high consumption of diesel causing harsh pollutant built up at the atmosphere. To abate pollution caused by diesel engine exhaust US, European and other environment protection agencies are going tougher for diesel emission standards and aiming at Ultra low sulfur diesel (ULSD) or S-15 ( ULSD can contain maximum 15ppm of sulfur, which is 97% less than low sulfur diesel).

Use of ULSD indeed will trim-down the pollution from diesel engine exhaust however there are numerous other issues associated with ULSD as a fuel, biggest of them is lubricity (It is a measure of a fuel’s ability to prevent wear in system components). In conventional diesel sulfur present is sufficient for providing desired lubrication, but in a case of ULSD additives for lubrication is required to meet ASTM standard. Another vital difficulty with ULSD is presence of significant higher amount of dissolved water due to hydrotreating (about 10 fold), this water caused freezing in winter and microbial growth in warm weather. Fuel’s oxidative stability is its resistance to the formation of gum and insoluble oxidation product which can plug filter and may lead engine to poor perform. Fuels’ poor oxidative ability and microbial growth can impact shelf life, and today’s clean fuels have very short shelf life compared to fuels of 20 year ago. Shelf life of EPA mandated ULSD is from 3 to 6 months. Increase in amount paraffin (wax) contain in ULSD compared to normal diesel is another glitch of desulfurization process. During cold weather paraffin (wax) present in diesel begins to form crystals, these crystal eventually plug the filter, starve the engine and prevent from starting. Cold start has always been hiccup for diesel engine, low temperature of combustion chamber, piston head and cold air intake makes evaporation of diesel difficult, which leads to engine having difficulty at the time of start and sluggish for a considerable time of starting. Cold start also leads to incomplete combustion and smoke formation.

In today’s day and age alcohols are widely accepted as a clean fuel additives , oxygenates and also fuel for the future. There are several limitations to using lower alcohols in compression ignition engine (diesel engine), particularly methanol and ethanol due their lower energy density, low cetane number and limited miscibility with diesel. On other hand n-butanol is completely miscible with diesel and sparingly with water, has higher energy density and higher cetane number compared to ethanol. Though experience with diesel engine running on butanol blended fuel is quite limited, biobutanol has potential to overcome some of drawback of LSD/ULSD and to reduce demand of petroleum fuels without much compromising on energy density and emission properties.

Butanol as Diesel fuel Blend

Fuel consumption and economy is the key factor to consider any renewable fuel for the replacement of fossil fuel. Switching from petro diesel to butanol blend diesel definitely would result in higher consumption of fuel. Heating value of petro ULSD is 19183 btu/lb and that of n-butanol is 14766 btu/lb which is 77% of petro diesel’s heating value and almost same as that of biodiesel’s(92% of biodiesel). In theory 20% and 40% butanol-diesel blend will result in the fuel consumption penalty of about 5% and 10% respectively. Use of ethanot in gasoline is widely practised as renewable fuel, but the similar use of ethanol in diesel is not widely accepted, one of the barrier to the use of ethanol and lighter alcohols in diesel fuels is limited miscibility especially at lower temperatures and need of the emulsifier. Whereas, butanol can be completely mixed to the diesel fuel in any concentration and it doesn’t separate at lower temperature or on addition of water and hence can be mixed with diesel anywhere in the supply chain. Complete miscibilty of butanol-diesel blend and non-corrosive and non volatile nature of butanol makes transportation and handling lot more easier than lower alcohols.

Butanol as diesel fuel additive:

Linear, primary alcohols have better lubrication property than paraffin or iso-paraffin which makes them excellent additive for clean diesel fuel for the improvement of lubricity and butanol can be most preferred due to its similarity with diesel fuel. Atomization characteristic of diesel and even bio-diesel can be improved by blending with butanol. Butanol could be used to reduce the viscosity, density and surface tension of the fuel blend on which the atomization characteristic of any fuel depends.

In theory, a hydrocarbon fuel when burned should produce only water and carbon dioxide as exhausted gases. However, such ideal combustion rarely occurs even in most perfectly adjusted engine. What is actually produced is the large amount of carbon monoxide, oxides of nitrogen, particulates and unburned hydrocarbons. When butanol is blended with fuel (gasoline/diesel) it can serve as an oxygenate and may help to mitigate the emission or air pollution.

Blending of butanol with ULSD can improve engine’s cold weather and cold flow performance. Due to low latent heat (less than half of ethanol) of butanol is less likely to cause starting difficulties or problem during warm up. According to the report published by Argonne National Laboratories blending butanol with diesel may also extend cold flow properties and oxidative properties. The problem of plugging of filter due to crystallization of wax at lower temperature can also be curtailed by addition of butanol, as butanol can reduce the solidification temperature of fuel at lower temperature. (Source: Smith and Workman)

Like other fuels, butanol also has limitations like low cetane number, exposure to its vapor may cause eye, nose throat irritation and the biggest challenge is high production cost.

Sources:

Argone Investing Butanol/Diesel Blends in Light-Duty Vehicles.
Alcohols for motor fuel
Impact of of biofuels on emission reducing technologies for off road diesel engines
Effects of ULSD
Butanol fast emerging as nextgen biofuel