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- Sets a limit based off the amount of C emitted
- 2. Penalization is determined from cap and trade programs (so you don't have to penalized if you just by someone else's leeway)
- 3. Argument against this: paying people to pollute
- 4. Sucess? IT WORKED! limestone reacts with sulfate -> CaSO4 + CO2
- a. Fluidized bed technology
out in wyoming, low sulfur, incentive for low sulfate emissions, environmentalists now embrance cap and trade
cap and trade in europe
- 1. failure bc gave out too many credits to other ppl by the politicians, price driven down and down
- 1. Sets the price of emissions and allows the market to determine the amount of emission reductions
- a. does NOT include market trading mechanism
- b. easier to administer & more cost efficient than emiss. limits
attempt to value the cost of pollution, or the public bad of this
Renewable Natural Gas
- 1. originates from wastestreams from farms (anything you do anaerobic digestion to)
- 2. comes from garbage
- 1. taxes discourage certain behaviors
- 2. subsidies that encourage certain behaviors
- 1. education do the common good
- 2. support research
- 3. laws
- 4. taxes to discourage behavior
- 5. subsidies that encourage certain behavior
What stands in the way of grain-to-ethanol fuel being a very high energy efficiency process?
Energy consumed in distillation of ethanol and drying of DDGS.
Describe the major operations in:Dry milling of grain to ethanol
- Milling; liquefaction (starch cooker); saccharification; fermentation; separation of DDGS; distillation of ethanol
- (6 processes)
Wet milling of grain to ethanol process?:
Steeping; milling; hydrocycloning to separate germ from hull and endosperm; extraction of corn oil from germ; milling of hull and endosperm and separation into hull (fiber) and starch and gluten; centrifugal separation of gluten; liquefaction of starch; saccharification of dextrin; fermentation of glucose; distillation of ethanol.
What are the comparative advantages of dry milling and wet milling?
Dry milling is simpler with lower capital costs; wet milling produces more valuable co-products and has more flexibility in changing mix of products.
Why should we expect converting cellulose to sugars to be so much tougher than converting starch to sugars?
- 1. First is the structure of lignocellulosic biomass, which does not allow enzymes or acids to penetrate to all of the cell walls.
- 2. Second is the crystalline structure of cellulose, making it difficult for enzymes to attack.
- 3. Third is the presence of lignin, which interferes with enzyme activity.
Describe major differences in production of ethanol from grain and lignocellulosic biomass.
- 1. Pretreatment of lignocellulose to release carbohydrate is more difficult; both hexose and pentose sugars are released and must be fermented;
- 2. lignin is presently a less valuable co-product than DDGS.
There are 3 major approaches to using enzymatic hydrolysis for production of cellulosic ethanol – what is distinctive about each approach and what is the advantage of each?
Separate hydrolysis and fermentation – undesirable interactions are avoided; simultaneous hydrolysis and fermentation – glucose removed before it inhibits further hydrolysis of cellulose; consolidated bioprocessing – reduces number of reactors and reduces costs of chemicals.
Are there any cellulosic ethanol plants operating or under construction in Iowa?
- Three: DuPont plant in Nevada;
- Poet plant in Emmetsburg;
- Quad Counties Corn Processors in Galva.
Why is Iowa an attractive place to build cellulosic ethanol plants?
already being grown in the form of corn stover
Can we envision greenhouse gas emissions actually going negative during production and distribution of cellulosic ethanol?
- 1. The first step in going “carbon negative” is to eliminate all fossil fuels in the production of energy crops and in their processing to biofuels.
- a(. This includes natural gas currently used to produce nitrogen fertilizer and dry feedstocks or distill ethanol and diesel fuel currently used for crop cultivating and harvesting equipment. At best, this gets us to “carbon neutral.” )
- 2. tillage practices that build soil carbon –
- a.Ex/ perennial crops can actually achieve this by reducing erosion of soils and oxidation of soil carbon.
1. producing pathway for producing hydrocarbons via fermentation of sugars from starch or cellulose
- Three possibilities:
- 1.Ferment to ethanol and then catalytically convert ethanol to hydrocarbons;
- 2. Ferment to triglycerides then hydrodeoxygenate these to hydrocarbons (diesel fuel). (triglyc. then take out oxygen)
- 3. Ferment to terpenes, which require less upgrading to hydrocarbons than the other two approaches.
Name four of the six advantages of thermochemical processing compared to biochemical processing.
- (1) Larger range of products;
- (2) shorter reaction times;
- (3) catalysts are cheaper than biocatalysts; (4) do not need to operate under sterile conditions;
- (5) easier to recycle catalysts than biocatalysts;
- (6) smaller scale plants can be economical (in some instances).
What are the four mechanistic steps in the combustion of solid fuel?
- 1. Heating and drying;
- 3.flaming combustion;
- 4. char combustion.
Advantage and disadvantage of direct combustion of biomass compared to other thermochemical or biochemical processes?
- 1. The advantage of burning biomass is that it employs well developed, commercially available technology;
- 2.a. the disadvantages are thermal penalties associated with burning high moisture fuels;
- b. ash fouling due to alkali content of biomass; and
- c. relatively low efficiency of small scale steam power plants.
- 1. High T conversion of solid,
- 2. carbonaceous fuels under oxygen-starved conditions to produce a flammable gas mixture.
Name four of the six major contaminants in syngas?
- 1. Particulate matter (PM);
- 2. tar;
- 3. sulfur;
- 4. nitrogen;
- 5. alkali metals;
- 6. chlorine.
1. Rapid thermal decomposition of organic compounds in the 2 . absence of oxygen to produce 3. predominately liquids
Provide a description of bio-oil in terms of its various phases.
- 1. Bio-oil is an emulsion of lignin-derived oligomers, (pyrolytic lignin) and a suspension of char particles in an aqueous phase composed primarily of carbohydrate-derived compounds.
- (3 parts)
Bio-oil superficially resembles petroleum, but it cannot be refined in exactly the same manner as petroleum. What is the main reason?
- 1. Bio-oil cannot be distilled
- 2. very reactive and forms non-volatile oligomers.
Interaction of a solvent with a solid or liquid reactant to produce chemical products.
Name a comparative advantage and disadvantage of solvolysis compared to pyrolysis.
- 1. Advantages :
- a. include partial deoxygenation of products and
- b. ability to process high moisture feedstocks.
- 2. The disadvantage is operation at elevated pressure.
break large molecules into lower boiling point molecules that can more easily be upgraded.
- 1. hydrogenation to remove heteroatoms (sulfur, nitrogen, chlorine, and oxygen)
- (mild conditions)
- 1. remove molecular hydrogen from hydrocarbons (and other organic compounds)- can be thought of as the reverse of hydrogenation.
- [Remove H's and other organic comp.]
convert two small molecules into a single fuel-range molecule.
1. Rearrangement (isomerization) of chemical bonds among the constituents (same formula dif. properties)
of a molecule to produce a molecule with the same chemical formula but distinctive chemical and physical properties
Two main objectives when processing derived molecules to renewable gasoline and diesel
- 1. Removing oxygen (to produce hydrocarbons) and
- 2. refining to molecules in the boiling range of traditional transportation fuels (through cracking of large molecules or combining of small molecules)
Give some examples of the several classes of oleaginous biomass: oil seed crops, unconventional crops, aquatic species, and waste streams
- 1. Oil seed crops: such as rapeseed and soybeans;
- 2. unconventional crops: jatropha and jojoba;
- 3.species like microalgae; and
- 4. waste streams like animal manure and sewage.
Compounds of biological origin that are soluble in organic solvents
What is found in the residual material after extracting lipid from an oleaginous feedstock? (NO lipid)
Protein, carbohydrate, fiber, and ash.
3 extraction practices for getting lipids from algae
- 1. Dry filter cake –
- 2. Wet filter cake: lipid extraction from wet algae (20% solids) followed by hydrothermal processing or anaerobic fermentation of the algal remnant (whole algae could also be processed by HTP or AF).2.
- 3. Fermented filter cake :hydrolysis of filter cake, fermentation of whole slurry, distillation of ethanol, solvent extraction of lipids, and anaerobic digestion of protein-rich residue.
Describe the process of transesterification of triglycerides to biodiesel.
- 1. triglyceride + methanol w/ base or acid catalyst -> 1glycerol + 3 methyl esters
- 2. Phase separation and wash process
Describe hydroprocessing of triglycerides (in contrast to transesterification)
- 1. Hydroprocessing hydrocracks 3 fatty acid chains from the 3- carbon backbone
- 2. Next hydrodeoxygenation of the fatty acid chains, saturation of any double carbon bonds and hydrogenation of the 3-carbon backbone to propane.
Anaerobic digestion to methane is a relatively simple process – why has it not been adopted more widely in the United States?
- 1. The main product is methane, which competes poorly with abundant natural gas in the U.S.
- 2. It has also encountered technical problems with corrosion of pipes by hydrogen sulfide formed during anaerobic digestion.
What are some advantages to anaerobic digestion compared to other biological processing options?
- 1. operates in non-sterile conditions;
- 2. automatic separation of product (outgassing);
- 3. simple systems.
What role does anaerobic digestion of wastes play in mitigating global climate change?
1. If wastes are allowed to decompose in open lagoons or storage pits, the methane formed is released to the atmosphere, where it acts as a much stronger greenhouse gas than carbon dioxide.
What are the three biological steps involved in anaerobic digestion?
- 1. Hydrolysis to long-chain acids, amino acids, and sugars;
- 2. acidification to carboxylic acids, hydrogen and carbon dioxide;
- 3. methanogenesis to methane and carbon dioxide.
- HAM! AD wants ham
- Long, hollow cells that
- 1. provide structural support and/or
- 2. conduct water and nutrients through the plant
Disintegration of plant material to recover fibers.
What problem did wood pulping solve (dating back to the early 1800’s)?
Shortage of rags for production of paper.
What contributed to the decline in the use of pulps from herbaceous plants (vs. wood)?
1. sulfite and sulfate (kraft) processes that converted wood into pulp. Wood is easier to collect and produces stronger fibers with less wastage.
Briefly describe the three major methods of wood pulping.
- 1. Sulfite pulping
- 2. Sulfate pulping
- 3. Organosolv pulping
- 1. uses organic solvents to solubilize lignin and hemicellulose,
- leaving behind cellulose pulp and relatively unmodified lignin
Improvement on soda (alkaline) pulping, which uses sodium sulfate instead of sodium carbonate as source of NaOH. Products are cellulose pulp and black liquor
1. Acidic bisulfite solution sulfonates lignin in about two hours allowing cellulose pulp to be washed out. The spent liquor in modern times is treated to precipitate lignosulfonic acids.
Negative environmental impact of the sulfite process (see process flow diagram in text and slides)?
In the early history of sulfite pulping, the spent liquor, containing lignosulfonic acids, degraded polysaccharides, and pulping chemicals, were dumped into rivers.
What is it about the Kraft process that makes its environmental impact generally smaller?
The pulping chemicals are recovered and the black liquor is burned, reducing the amount of waste stream.
What does depithing of herbaceous plant stalks accomplish?
1. Removes parenchyma cells (pith) and waxy epidermis cells from stalks, reducing cost of pulping and improving quality of pulp.
4 potential benefits of GMO’s to agriculture and biomass production?
- 1. provides resistance to herbicides
- 2. protect against pests
- 3. provide hardiness against frost
- 4. improve nutritional or feedstock value
What are the four main environmental and safety concerns about GMO’s?
- 1. superweeds
- 2. loss of biodiversity
- 3. transgenes in GMO’s jump to humans
- 4. toxins from GMO’s disrupt ecosystems
What three questions need to be answered in risk assessment of GMO’s?
- 1. Does introduction of GMO’s present more pests than original;
- 2. if a transgene is transferred to a wild species, does this represent a threat to biodiversity;
- 3. would adoption of stress-tolerant plants lead to significant loss of natural ecosystems?
6 Negative environmental impacts that can arise from poor agriculture practices?
- 1. Loss of soil fertility;
- 2. soil erosion;
- 3. water pollution;
- 4. air pollution;
- 5. reduced biodiversity;
- 6. net GHG emissions
- FEP BP
What are the four major chemical elements that account for soil fertility?
What are the seven mechanisms by which inorganic nutrients get into the soil in the first place?
Volcanic eruptions, mountain erosion, glacial till, flooding, dust storms, biological nitrification, and biological transport (manure).
Briefly indicate how the four major chemical elements are lost from soils as a result of agriculture.
- Organic carbon: erosion and oxidation
- Nitrogen: biomass removal; gaseous emissions from microbial activity; leaching of nitrates from soil
- Phosphorous: biomass removal; soil erosion
- Potassium: biomass removal; leaching of soils
What are the undesirable effects of excessive nitrogen and phosphorous in water supplies?
- 1. Excess nitrate in drinking water is a health hazard to babies and causes
- 2. eutrophication of coastal (sea) waters;
- 3. phosphorous leads to eutrophication in river and lake ecosystems. ( I Pee in a lake)
Name five ways that agriculture directly contribute to GHG emissions?
- 1. Production of ammonia fertilizer from natural gas;
- 2. burning diesel fuel in tractors;
- 3. release of CO2 from soil cultivation; 4. microbial oxidation of ammonia fertilizer releases NO and N2O;
- 6. cattle and rice cultivation release methane.
indirect land use change
Conversion of natural ecosystems into farmland due to global competition between food and biofuel production with an attendant release of GHG emissions.
What are four problems with the theory of ILUC?
- 1. Corn supply has outstripped incremental increase in demand by ethanol industry;
- 2. It is impossible to predict how people around the world will respond to changes in world agricultural markets;
- 3. Empirical evidence does not support ILUC as explanation for deforestation;
- 4. It application to biofuels policy will not slow the pace of deforestation (worst case scenario: ILUC only accounts for 25 million acres of 500 million acres lost to deforestation).
Name five ways that agriculture could contribute toward reducing global climate change.
- 1. Divert manure to covered anaerobic digesters
- 2. If care is taken to protect against loss of soil carbon and renewable energy is employed in crop production, agriculture can provide bioenergy feedstock with no net carbon emissions
- 3. Roots, which are underground plant material, contribute to soil humus, which could be sequestered for centuries
- 4. Plantations of short rotation woody crops might increase carbon inventories of soil by 30 – 40 Mg/ha over a period of 20 – 50 years
- 5. Integration of production of biofuels and biopower with biochar application to crop lands could result in carbon negative energy - also called Greenhouse Gas Removal (GGR)
During production of heat and power describe the six forms of air pollution that nitrogen, sulfur, and chlorine can form.
- 1. Acid rain from sulfur and nitrogen oxides; urban ozone from nitric oxide (NO);
- 2. smog from ozone and volatile organic compounds (VOC);
- 3. PM 2.5 from sulfate and nitrate;
- 4. dioxin from chlorine compounds;
- 5. GHG emissions from N2O and fossil-derived CO2.
What are the five ways policy makers encourage public adherence to policies?
- 1. Educate the public about “public good” of policies
- 2. Support research that makes it possible for citizens to abide by policy
- 3. Laws with criminal or civil penalties for those that do not obey policy
- 5. Taxes that discourage certain behaviors Subsidies that encourage certain behaviors
List the five types of subsidies
- 1. Income tax credits
- 2. Direct payments
- 3. Indirect payments
- 4. Mandates
- 5. Loan guarantees
Describe income tax credits as a subsidy and give an example.
Reduces a taxpayer’s income tax liability below the amount required by the tax rate. Examples include deductions (partial tax credits) on federal taxes on such things as dependent children, interest on home loans, charitable donations; the $1.01 per gallon tax credit for production of cellulosic biofuels.
Describe direct payments as a subsidy and give an example.
A direct monetary transfer from the government to the producer, not necessarily based on profitability. Examples include direct payments to fuel and food producers in various countries around the world to allow them to sell products at below market prices. In the U.S., the (now defunct) $0.45 per gallon blender’s credit that was paid regardless of profitability of a biofuel producer.
Describe indirect payments as a subsidy and give an example.
Monetary transfers dictated by the govt from one private entity to another. An example is the U.S. Renewable Fuel Standard of 20007 (RFS2) that required blenders to purchase “obligated volumes” of biofuels from producers, which were tracked with Renewable Identification Numbers (RINS).
Describe mandates as a subsidy and give an example
Government programs requiring domestic production and/or consumption of a particular commodity or product by specific entities. Examples include the U.S. Renewable Fuel Standard and various state and national Renewable Portfolio Standards.
Describe loan guarantees as a subsidy and give an example.
Government guarantees repayment of private loans to lenders if the borrower defaults. Examples include federal student loan programs and the guaranteed loan programs of the U.S. Department of Energy (DOE) and U.S. Department of Agriculture (USDA) for companies to build renewable fuel and power facilities.
Describe emission prices as a way to control pollution emissions
Sets a limit on emissions permitted, with the price of emissions often regulated through cap-and-trade programs.
Explain a cap-and-trade program for control of pollution emissions. Give an example where cap-and-trade has been implemented to control pollution emissions.
Emitters exceeding their annual emission caps for a particular pollutant must purchase tradable emission allowances from companies that operate below their allowances. Examples include the U.S. program to reduce atmospheric sulfur emissions; the EU program to reduce greenhouse gas emissions; and California’s Low Carbon Fuel Standard.
Describe emission taxes as a way to control pollution emissions
Sets the price of emissions and allows the market to determine the amount of emission reductions