Algal Biodiesel Production for Bio-Fuel Feedstock, Carbon Sequestration & Emission Reduction

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Algal Biodiesel Production for Bio-Fuel Feedstock, Carbon Sequestration & Emission Reduction

Aman1

1Scholar, MDU, UIET, Rohtak

Abstract: This communication seeks to raise discussion related to finding a low capital cost algae treatment process where one basic design can be applicable to a wide variety of industrial waste effluent situations. The emphasis is on economy of scale derivable from a large market and by seeking design simplicity. It is suggested that this industry has future potential for multibillion dollar economic activity worldwide. This justifies more detailed consideration than is given in the present communication. The approach suggested is to combine open racecourse algae ponds with on-site flash pyrolysis. Waste materials, including CO2, can be recycled to produce pyrolytic oil, combustible gas and charcoal. The more conventional approach to producing Biodiesel from algae is in the closely-controlled and e according to its advocates. The surge of interest in biodiesels has highlighted a number of environmental effects associated with its use. These potentially include reductions in greenhouse gas emissions, deforestation, pollution and the rate of biodegradation. enclosed photo bioreactor

Keywords Biodiesel, Photo bioreactor, Carbon Dioxide, Algae

INTRODUCTION :

In the past century, it has been seen that the consumption of non-renewable sources of energy has caused lot of environmental damage. Electricity generated from fossil fuels such as coal and crude oil has led to high concentrations of harmful gases in the atmosphere. This has in turn led to many problems being faced today such as ozone depletion and global warming. Therefore, alternative sources of energy have become very important and relevant to todays world. These sources, such as the sun and wind, can never be exhausted and therefore are called renewable. They cause less emission and are available locally. Their use can, to a large extent, reduce chemical, radioactive, and thermal pollution. They are a viable source of clean and limitless energy. These are also known as non-conventional sources of energy.Under the category of renewable energy or non-conventional energy are such sources as the sun, wind, water, agricultural residue, firewood, and animal dung. The non-renewable sources are the fossil fuels such as coal, crude oil, and natural gas.

Energy generated from the sun is known as Solar Energy. Hydel is the energy derived from water.

  • Geothermal Energy is derived from hot dry rocks, magma, hot water springs, natural geysers, etc.

  • Ocean Thermal is energy derived from waves and also from tidal waves.

  • Biomass firewood, animal dung, biodegradable waste from cities and crop residues- is a source of energy when it is burnt.

    Carbon sequestration is a geo engineering technique for the long-term storage of carbon dioxide or other forms of carbon, for the mitigation of global warming. Carbon dioxide is usually captured from the atmosphere through biological, chemical or physical processes. It has been proposed as a way to mitigate the accumulation of greenhouse gases in the atmosphere released by the burning of fossil fuels.

    CO2 may be captured as a pure by-product in processes related to petroleum refining or from flue gases from power generation.

    CO2 sequestration can then be seen as being synonymous with the storage part of carbon capture and storage which refers

    to the large-scale, permanent artificial capture and sequestration of industrially-produced CO2 using subsurface saline aquifers, reservoirs, ocean water, aging oil fields, or other carbon sinks.

    1. BIODIESEL

Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl (methyl, propels or ethyl) esters. Biodiesel is typically made by chemically reacting lipids (e.g., vegetable oil, animal fat (tallow)) with an alcohol.

Biodiesel is meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrol & diesel. The term "biodiesel" is standardized as mono-alkyl ester in many countries.

Blends of biodiesel and conventional hydrocarbon-based diesel are products most commonly distributed for use in the retail diesel fuel marketplace. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix: fuel containing 20% biodiesel is labeled B20, while pure biodiesel is referred to as B100. It is common in the USA to see B99.9 because a federal tax credit is awarded to the first entity which blends petroleum diesel with pure biodiesel . Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines. Biodiesel can also be used in its pure form (B100), but may require certain engine

modifications to avoid maintenance and performance problems. Blending B100 with petroleum diesel may be accomplished by:

  • Mixing in tanks at manufacturing point prior to delivery to tanker truck

    Biodiesel has virtually no sulfur content, and it is often used as an additive to Ultra-Low Sulfur Diesel (ULSD) fuel.

    1. MATERIAL COMPATIBILITY

  • Splash mixing in the tanker truck (adding specific Plastics: High density polyethylene (HDPE) is

    percentages of Biodiesel and petroleum diesel)

  • In-line mixing, two components arrive at tanker truck simultaneously.

Metered pump mixing, petroleum diesel and Biodiesel meters are set to X total volume, transfer pump pulls from two points and mix is complete on leaving pump.

2. APPLICATIONS

Biodiesel can be used in pure form (B100) or may be blended with petroleum diesel at any concentration in most injection pump diesel engines, New extreme high pressure (29,000 psi) common rail engines have strict factory limits of B5 or B20

compatible but polyvinyl chloride (PVC) is slowly degraded. Polystyrenes are dissolved on contact with biodiesel.

  • Metals: Biodiesel has an effect on copper-based materials (e.g. brass), and it also affects zinc, tin, lead, and cast iron. Stainless steels (316 and 304) and aluminum are unaffected.

  • Rubber: Biodiesel also affects types of natural rubbers found in some older engine components. Studies have also found that fluorinated elastomers (FKM) cured with peroxide and base-metal oxides can be degraded when biodiesel loses its stability caused by oxidation.

    depending on manufacturer. Biodiesel has different solvent properties than petrodiesel, and will degrade natural rubber gaskets and hoses in vehicles (mostly vehicles manufactured before 1992), although these tend to wear out naturally and most likely will have already been replaced with FKM, which is nonreactive to biodiesel. Biodiesel has been known to break down deposits of residue in the fuel lines where petrodiesel has been used As a result, fuel filters may become clogged with particulates if a quick transition to pure biodiesel is made. Therefore, it is recommended to change the fuel filters on engines and heaters shortly after first switching to a biodiesel blend.

    1. CONTAMINATION BY WATER

      Biodiesel may contain small but problematic quantities of water. Although it is not miscible with water, it is, like ethanol, hygroscopic (absorbs water from atmospheric moisture).One of the reasons biodiesel can absorb water is the persistence of mono and diglycerides left over fom an incomplete reaction. These molecules can act as an emulsifier, allowing water to mix with the biodiesel. The presence of water is a problem because:

      Water reduces the heat of combustion of the bulk fuel. This means more smoke, harder starting, less power.

      3. PROPERTIES

      Biodiesel has better lubricating properties and much higher

      cetane ratings than today's lower sulfur diesel fuels.

  • Water causes corrosion of vital fuel system

    components: fuel pumps, injector pumps, fuel lines, etc.

  • Water & microbes cause the paper element filters in the system to fail (rot), which in turn results in premature failure of the fuel pump due to ingestion of large particles.

    Biodiesel addition reduces fuel system wear, and in low Water freezes to form ice crystals near 0 °C (32 °F).

    levels in high pressure systems increases the life of the fuel injection equipment that relies on the fuel for its lubrication.

    These crystals provide sites for nucleation and accelerate the gelling of the residual fuel.

    Depending on the engine, this might include high pressure Water accelerates the growth of microbe colonies,

    injection pumps,pump injectors (also called unit injectors) and fuel injectors.

    which can plug up a fuel system. Biodiesel users who have

    heated fuel tanks therefore face a year-round microbe problem.

    The calorific value of biodiesel is about 37.27 MJ/L. This Additionally, water can cause pitting in the pistons

    is 9% lower than regular Number 2 petrodiesel. Variations in biodiesel energy density are more dependent on the feedstock used than the production process. Still these variations are less than for petrodiesel. It has been claimed biodiesel gives better lubricity and more complete combustion thus increasing the engine energy output and partially compensating for the higher energy density of petrodiesel.

    Biodiesel is a liquid which varies in color between golden and dark brown depending on the production feedstock. It is immiscible with water, has a high boiling point and low vapor pressure. *The flash point of biodiesel (>130

    °C, >266 °F) is significantly higher than that of petroleum diesel (64 °C, 147 °F) or gasoline (45 °C, -52 °F). Biodiesel has a density of ~ 0.88 g/cm³, less than that of water.

    on a diesel engine.

    Previously, the amount of water contaminating biodiesel has been difficult to measure by taking samples, since water and oil separate. However, it is now possible to measure the water content using water-in-oil sensors.

    Water contamination is also a potential problem when using certain chemical catalysts involved in the production process, substantially reducing catalytic efficiency of base (high pH) catalysts such as potassium hydroxide. However, the super-critical methanol production methodology, whereby the transesterification process of oil feedstock and methanol is effectuated under high temperature and pressure, has been shown to be largely unaffected by the presence of water contamination during the production phase.

    1. SOURCES OF BIODIESEL

    A variety of oils can be used to produce biodiesel. These include:

    • Virgin oil feedstock; rapeseed and soybean oils are most commonly used, soybean oil alone accounting for about ninety percent of all fuel stocks in the US. It also can be obtained from field pennycress and atrophy and other crops such as mustard, flax, sunflower, palm oil, coconut, hemp.

    • Waste vegetable oil (WVO);

    • Animal fats including tallow, lard, yellow grease, chicken fat,and the by-products of the production of Omega-3 fatty acids from fish oil.

    • Algae, which can be grown using waste materials such as sewageand without displacing land currently used for

      with the specially chosen algae strains selected to optimize oil production.

      1. ALGAE PHOTO-BIOREACTORS (APBs)

        Absorption of CO2 and NOx from industrial exhaust gases and conversion of algal feedstock, as a discipline of ecological engineering. Algae, live in a wide range of aquatic environments and are a natural component of most aquatic ecosystems being found in both fresh, brackish and marine waters. They range in size from large macrophysics kelps to microscopic unicellular, colonial and filamentous algae, known as phytoplankton. They are also the fastest growing plants on earth ten times faster than trees – with the more efficient species doubling their volume every 6 hours.

        food production.

    • Oil from halophytes such as salicornia bigelovii, which can be grown using saltwater in coastal areas where conventional crops cannot be grown, with yields equal to the yields of soybeans and other oilseeds grown using freshwater irrigation

        1. YIELD

          Feedstock yield efficiency per unit area affects the feasibility

  • Microscopic microalgae, are typically free floating

    in the water column (planktonic) and encompasses several groups of relatively simple organisms that capture light energy through photosynthesis, using it to convert inorganic substances into organic matter. Photosynthesis is a method used by plants to produce glucose from sunlight, carbon dioxide and water, with oxygen as a waste product. Phytoplankton, have much faster growth-rates than terrestrial crops, their productivity is between two to five times higher, compared with traditional agricultural crops.

    of ramping up production to the huge industrial levels There are over 2800 species (and a further 1300

    required to power a significant percentage of vehicles.

    Some typical yields

    S.

    No

    Crop

    Yield

    Litre/Hectare

    US

    gal/acre

    1

    Chinese tallow

    907

    97

    2

    Palm oil

    4752

    508

    3

    Coconut

    2151

    230

    4

    Rapeseed

    954

    102

    5

    Soy (Indiana)

    554-922

    59.2-

    98.6

    6

    Peanut

    842

    90

    7

    Sunflower

    767

    82

    8

    Hemp

    242

    26

    9

    Algae

    ~3,000

    ~300, 1500-3000

    The debate over the energy balance of biodiesel is ongoing. Transitioning fully to biofuels could require immense tracts of land if traditional food crops are used (although non food crops can be utilized). The problem would be especially severe for nations with large economies, since energy consumption scales with economic output.

      1. ALGAE AS SOURCE OF BIODIESEL

        Algae fuel yields have not yet been accurately determined, but DOE is reported as saying that algae yield 30 times more energy per acre than land crops such as soybeans. Yields of

        36 tonnes/hectare are considered practical. The more conventional approach to producing Biodiesel from algae is in the closely-controlled and enclosed photo bioreactor. In such systems great care must be taken to exclude wild algae and bacteria. These are more vigorous and would compete

        infraspecific taxa) of algae being reported from inland (non- coastal) Australia. An enclosed Algae Photo-Bioreactor (APB) consists of transparent tubes, cylinders or plates that receive a high density culture of algae under daylight conditions, with an option to illuminate the culture to provide greater performance. There is a holding tank, where the substance is continuously pumped around the circuit andwhere it achieves a regulatory dark phase. It is screened to harvest mature cells and water borne nutrients (preferably wastewater) are added and adjusted to the culture. The CO2 (82% reduction) and NOx exhaust gases from an industrial power plant are cooled and where the gases are injected into the solution post, dark phase.

  • Algae reduces NOx day and night, regardless of temporal and weather conditions (even dying algae can reduce NOx by up to 70 percent.

    • It is suggested that an exactly opposite design approach may also have some merit. Why not allow the more aggressive algae to compete and overwhelm weaker rivals and simply aim to maximize crude biomass production? This approach would allow the open race-course method of algae production to be used which has much lower capital costs. This method also dictates the need for well-designed low energy input for handling the resulting biomass and its treatment. It is suggested that on-site flash pyrolsis may be the best approach and this would produce a reasonably consistent by-product (oil content approaching 70%of the original biomass). It is suggested that the rotating-cone flash pyrolyser ( PyRos design) may be the most suitable plant. The rotating cone pyrolyser has many advantages. It is simple, inexpensive, robust, works at atmospheric pressure and it can be easily scaled to the size required by using multiple units on the same drive. It uses ordinary sand which is also recyclable.

  • In the proposed process it is necessary that all nutrient for the algae ponds shall be reduced to liquids, be this dissolved CO2, sewage or any other waste. This keeps pumping and pipeline costs to minimum levels. In industry these gaseous pollutants would normally be reduced to a liquid by passing them through a scrubber. This is a normal part of a modern plant producing gaseous waste.

Major issues to be addressed.

  • Identifying strains of algae with high productivity, carbon uptake & oil content

  • Optimizing production parameters to achieve the above

  • Design & development of low-cost diffusers for maximum CO2 transfer

  • Design & development of low cost photo bio-reactor with optimal efficiency

  • Devising solar collectors and lighting fixtures for continuous reactor operation

  • Sustainable production of high-oil-yielding algae strains

  • Ability to extract oil from the algae on a large scale

  • Large-scale conversion of algal oil into bio-diesel

By-product synergy to ensure total utilization of biomass including food/fodder

  1. WHAT IS REQUIRED TO PRODUCE 1KG DRY

    ALGAL BIOMASS

    CO2: 1.7kg

    Water: 20-30L (22-35 *C)

    Nutrients: 40g Nitrogen 4g Phosphorus

    Temperature: 15-45 *C degrees

    The Algal dry biomass contains up to 46% Carbon, 10% Nitrogen and 1% Phosphates One kg of dry algal biomass utilizes up to 1.7 kg CO2 but generally a ratio of 1kg of algae to 1kg of CO2 is used for calculations

  2. PRODUCTION TARGETS

    It is expected that the optimization of process would ensure an uptake of 220 tonnes of carbon dioxide per hectare of land based on algae production of 1000 t/ha and an average uptake of 2.2 tonnes of carbon dioxide per tonne of algae produced. The long-term objective of continued improvement would aim at maximizing this figure of carbon dioxide sequestration to a level beyond 300t/hectare by the end of the project duration.

    Photosynthetic efficiency (the percentage of incident radiation that is converted into biomass) is aimed as 18 ~ 20

    %

    PV system support and LED/optic fiber based illumination to increase output corresponding to 22 hour/day operation

    Algal biomass must contain 60% lipid Daily harvesting rate maintained at 50%

  3. FUTURE RESEARCH GOALS

    Identification of New Species Development of Bio Catalysts Genetically Modified Algae Strains Nutrient uptake & lipid Content Synergy of Oil-cake Valorization

  4. CONCLUSION

Energy is a crucial input for development. The non renewable forms of energy are regarded as energy capital, and wisdom is by not spending the capital but conserving it. The energy crisis has shown that sustainability in the energy sector can be brought about by replacing them by renewable ones, which are more or less pollution free, environmentally clean and socially relevant. Infact, the challenge today is that the increasing requirements of energy are met by renewable sources of energy. Integrated energy systems have to be developed for optimally meeting the energy requirements.

REFERENCES

  1. Akers, M.S. et al, Determination of the Heat of Combustion of Biodiesel Using Bomb Calorimetry, Journal of Chemical Education, Vol. 83, No 2, February 2006

  2. Biodiesel Handling and use guidelines, Third Edition, September 2006, US Department of Energy

  3. Booth, E., et al, Economic Evaluation of Biodiesel Production from Oilseed Rape grown in North and East Scotland, October 2005

  4. Costa R. E. & Lora, E.E.S., "The energy balance in the production of palm oil biodiesel – two case studies: Brazil and Colombia"

  5. Demirbas, A., Progress and recent trends in biofuels, Progress in Energy and Combustion Science 33 (2007), pp. 118

  6. Roger Sedjo and Brent Sohngen (2012). "Carbon Sequestration in Forests and Soils". Annual Review of Resource Economics (Annual Reviews) 4: 127144. doi:10.1146/annurev-resource-083110- 115941.

  7. Stephen Bedford Clark fishace ecological engineering ishace@aapt.net.au www.fishace.com.au

  8. www.cleantechfoundation.org

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