Production of liquid fuels and Chemicals from Seaweed.
Advanced and microwave enhanced thermochemical Conversion of Seaweed and Algae Biomass to produce Liquid Fuels and Chemicals.
It is the most promising global-scale biomass solution is represented by micro and macro algae since they are Mother Nature’s most efficient practitioners of photosynthesis (the fixation of carbon dioxide), resulting in the It is the most promising global-scale biomass solution is represented by seaweed/microalgae since they are Mother Nature’s most efficient practitioners of photosynthesis (the fixation of carbon dioxide), resulting in the highest yields of biomass and oils among all aquatic species, which are in turn an order of magnitude more efficient than terrestrial plants.
The combined pressures of rising fuel prices, diminishing global supplies of crude oil and legislation to control climate change by reducing greenhouse-gas emissions has resulted in both aggressive renewable fuel policies and a rapid growth in the emerging bio fuels industry. As a result surplus agricultural feedstock's in the US and Europe are quickly being exhausted, contributing to commodity price
Increases. Algae is mostly used of one cellular type and seaweed or macro algae for aggregates of the first one and related.
As a result of the foregoing there has been a growing acknowledgement of, and emphasis on, next-generation type such as cellulose ethanol, algae-derived bio diesel and pyrolysis oil (bio-oil) from woody biomass. More recently, attention has turned to more advanced bio fuels made from renewable waste resources.
These more advanced bio fuels, renewable diesel, gasoline and jet fuel are literally seen as a replacements for today's diesel, gasoline and jet fuel products.
Thermo chemical conversion routes produced energy dense bio-oil
(35-37 MJ/kg) that approached shale oil (41 MJ/kg). Bio diesel has about 80% the energy density of kerosene but has the potential of being chemically converted into kerosene, the basic component of jet fuel. Jet fuel now accounts for about 8% of the petroleum use with very few renewable alternatives. Ethanol is not dense enough with only half the energy per volume of the jet fuel.
The residual biomass from oil extraction can be partly used as high protein animal feed and, possibly, as source of small amounts of other high-value micro algal products.
Solid bio fuels have a low energy density, which limits the commercial application to locations close to the place of production and in our case Ireland shores. One way to
solve this problem is the conversion of this feedstock into liquid fuel. These liquids have a much higher energy density and are easy to store and transport. Can be
Employed to convert wet biomass material to liquid fuel. This technology is believed to mimic the natural geological processes thought to be involved in the formation of fossil fuel, but in the time scale of hours or even minutes. A number of technical terminologies have been used in the literature to refer to this technology, but it essentially utilize the high activity of water in sub-critical conditions in order to decompose biomass materials down to shorter and smaller molecular materials with a higher energy density or more valuable chemicals/feed.
These bio fuels produced from renewable biomass are the sustainable energy resource with greatest potential for CO2 neutral production.
A sustainable and profitable Bio diesel production from micro algae is now possible. This second-generation bio fuel can overcome the energy and environmental needs by integrating the technologies.
Large quantities of algal biomass needed for the production of bio diesel could be grown in photo bioreactors combined with photonics and biotechnologies.
The direct hydrothermal liquefaction is currently the most energy efficient technique for producing bio diesel from algae without the need to reduce the water content of the algal biomass, which is high in average about 80%. The overall approach would adopt an integrated biomass-production conversion system. In addition to oil there is gas and steam, the oil part will contain about half of the energy part the rest is still dissolved in the water. It can include a micro algal production at thermal power plants for sequestering CO2, wastewater treatment and emission control, integration of an internal heat exchanger network and utilization of high pressure and high temperatures from the conversion reactor for power generation. Not all countries are located in a natural seaweed producing position.
A few companies are already underway to achieve commercial-scale, and available in the market. Analysis of the energy consumption ratio (ECR) also revealed that for wet algal biomass (80% moisture content), HTL is more favourable (ECR 0.44-0.63) than pyrolysis (ECR 0.92-1.24) due to required water volatilisation in the latter technique. In other climates which much drier air the pyrolysis process a better choice and seaweed conversion in to crude oil. The same would apply here if we were able to remove most of the watery part of the seaweed prior to conversion.
Test/research indicates that at optimum thermo chemical liquefaction (TCL) the yield was 39.9%. ? Carbon conversion efficiency for most TCL runs were >93%. ?
Bio crudes obtained at 350–380 °C had fuel properties close to petroleum crude.
A maximum bio-oil yield of 25.8% is obtained at a reaction temperature of 360 °C and a holding time of 50 min using 5% Na2CO3 as a catalyst. The bio-oil is composed of fatty acids, fatty acid methyl esters, ketones, and aldehydes. Its heating value is 30.74 MJ/kg.
Most bio-oil is currently produced in high-pressure vessels or autoclaves at pressures up to 200 bars. One publication and study 350 °C, ~200 bar in water, 1 M Na2CO3 and 1 M formic acid as catalyst. Other publication suggesting between 100-200 bars.
Alternative to the batch procedures are the gravity-based system and the needed pressure for the conversion the result of a liquid column (gravity) as high as 1000 meter resulting in the required pressure. A hole is drilled into the earth and two pipes go into it. Instead of drilling a deep hole you can place the pipes outside on the surface but will need a high and steep mountain to get enough high.
New developments might result in the maximum pressure needed using other catalyst, Microwave-assisted chemical liquefaction, limited oxidation by running DC currents through the slurry and more.
Energy utilization and specific energy requirements for microwave based bio diesel synthesis are reportedly better than conventional techniques but you are in need of access to the pipe. Microwaves can be very well utilized in feedstock preparation, extraction and trans esterification stages of the bio diesel production process. If the pressure need
for the process could be reduced to about 20-30 bar using the geographic available and difference in high
as present on the South West of Ireland a definitive advantage to others. Close to the shore and lower maintenance and construction cost. The physic-chemical characteristics were highly influenced by conversion route and feedstock
Sharp differences were observed in the mean bio-oil molecular weight (pyrolysis 280-360 Da; HTL 700-1330 Da) and the percentage of low boiling compounds (bp<400°C) (pyrolysis 62-66%; HTL 45-54%).
Bio crude productivity was highest for marine Derbesia (2.4gm-2d-1) and Ulva (2.1gm-2d-1), and for freshwater Oedogonium (1.3gm-2d-1).
There is another route called hydra-thermo chemical processing of algae biomass and provides an other no enzymatic route for de-polymerisation of biomass into sugars that can be used for the biological production of fuels and chemicals and operates at much lower pressures. (10-30 bar).
Best known as Acidic Hydrolysis.
Acid hydrolysis processes that are based on the use of either dilute or concentrated acid. The most widely used acids for this purpose are HCl and H2SO4. Dilute acid processes are conducted at high temperatures of 120 to 200 1C and pressures of 0.1 to 0.5MPa. The major advantage of dilute acid processes is the short reaction time, which is in the
range of seconds or minutes for continuous processes. The disadvantage is
their low sugar yield. Most dilute acid processes are limited to a sugar-recovery
efficiency of around 60% and used a base material for the production of fine chemicals.
The question why stop half way instead of going down the complete route?
Goudriaan et al. claim the thermal efficiency (defined as the ratio of heating values of bio-crude products and feedstock plus external heat input) for the hydrothermal upgrading process (HTU®) of biomass of a 10 kg dry weight h-1 pilot plant is as high as 75%. The main product of the process is bio-crude accounting for 45% wt. of the feedstock on dry ash free basis, with a lower heating value of 30-35 MJ kg-1, which is compatible with fossil diesel and can be upgraded further.
Biomass gasification itself will only be able to penetrate the market if it is completely integrated into a bio-energy system and have an efficiency of 15 % for the smaller units, which might increase to35-40 for the advanced ones. Prices indication form smaller units up to 13MWel given as 4.000 and 4.300 Euros per kWel