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SS17_I: Bioenergy Technology > Doris-Introduction > Flashcards

Doris-Introduction Flashcards

1
Q

Why renewables for transportation?

A
  1. Fossil Fuels run out
  2. Climate protection, reduction co2 emission from non -renewable sources
  3. Increasing demand for transportation, due to population growth and higher industrialization
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2
Q

What kind of biofuels for transportation do exist?

A

1st generation, 2nd generation… x-generation biofuels

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3
Q

Should we know the biofuel processing step by step in details?

A

Well she said in general but basically it’s a yes! ( should be simple) Bioethanol yields and comparing the efficiencies and energy balances

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4
Q

Give the bioethanol production pathways

A

-Hydrogeneration of Ethylene ( Mineral oil based technology ) - Homologation of methanol -Microbiological fermentation ( Add reactions) !

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5
Q

What kind of feedstocks could be used to derive bioethanol?

Give the following for each feedstock: ( Draw table)!!!!

  • Average crop yield[Mg / ha*a]
  • Ethanol yield per Mg feedstock [Liter / Mg]
  • Ethanol yieldper ha [Liter/ ha*a]
A

-Sugar crops ( cane and beet) - Starch crops ( corn and grains like wheat barley…) - Lignocellulose ( Wood, grass, straw, corn stover..)

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6
Q

Let’s focus on sugar crops, name typical sugar crops and the zones we can found them in!

A

Sugar beets: temperate zones for example europe

Sugar cane: tropical subtropical zones ( e.g Brazil)

Sweet Sorghum:tropical subtropical zones ( e.g India)

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7
Q

Where exactly does the fermentation take place for each crop type?

A

Sugars for fermentation

Soluble sugars stored in plant cell liquids: saccharose, glucose, fructose

 Sugar beet: in beet

 Sugar cane: in stems

 Sweet sorghum: in stems

Sugar crops are seasonal products and cannot be stored for long time

(microbial digestion)

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8
Q

Name one problem with the storage of sugar crops

A

SC are seasonal products and cannot be stored for long time ( microbial digestion)

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9
Q

Which are the steps of the sugar crops processing, define the inputs and outputs for each step? draw a graph!

A

Milling, sugar extraction, concentration, fermentation, distillation, rectification, dehydration, drying

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10
Q

Define:

  • Reserves
  • Resources
  • Coverage
A
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11
Q
  • Where does the formation of crude oil take place?
  • For crude oil please explain the difference between conventional reservoirs and non-conventional reservois:
A

Crude oil reservoirs

Formation of crude oil takes place in parent rock. Crude oil may diffuse fromparent rock to nearby rocks and accumulate (reservoir rock).

Subterranean non conventional reservoirs (e.g. „shale oil“) may be distinguised from conventional reservoirs by the properties of the reservoirrocks in terms of „porosity“ and „permeability“ requiring different recoverymethods–> recovery by fracking

Conventional crude oil: recovery by inherent pressure (drilling andpumping), supported by ground injection of gases (e.g. natural gas, CO2 , N2) or fluids (water, tenside solutions,…) if required –> up to 70% recovery

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12
Q

Where can we find the conventional reservoirs? and where do we find the nonconventional?

A

Conventional reservoirs

  • Near East
  • GUS
  • USA
  • Northern Sea
  • Venezuela
  • Africa

Non conventional reservoirs

  • Heavy crude oils
  • Oil sands (up to 18% oil) –> esp. Canada (Alberta), Venezuela (Orinoco)
  • Oil shale (up to 30% oil) –> esp. Venezuela, China, USA
  • (Deep sea reservoirs)
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13
Q

What does porositiy mean?

A

Indicates the share of pores in the reservoir rock (20-30% in good reservoir rocks of conventional deposits)

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14
Q

What does Permeability mean?

A

Indicates how easily fluids or gases may diffuse the reservoir rock–> also indicates the quality of connection of the pores in the rock.

1 Darcy –>Flow of 1 cm/s at fluid-viskosity of 1 mPa*s under pressure gradient of 1 atm/cm

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15
Q

Difference between conventional and unconventional in porosity and permeability?

A
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16
Q

Describe the fracking procedure:

A

Hydraulic fracturing - „Fracking“ procedure

1) Vertical drilling to thereservoir rock
2) Horizontal drilling (up to ~ 1km), installation of pipesand tightening with concrete
3) Perforation of horizontalpipes and injection of the„fracking fluid“(fluidpressure > minimum tension of the rock)  formation of fractures inthe rock, mainly in vertical direction
4) Recovery of fracking fluid and crude oil

Fracking fluids

contain ~ 98 % Wasser und various additives

up to ~ 30 Mio. litres per well required

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17
Q

What is the composition of fracking fluids?

A

Fracking fluids

contain ~ 98 % Wasser und various additives

up to ~ 30 Mio. litres per well required

Important ingredients:

 „Proppants“: ceramic balls, covered by phenolic or epoxid resins for pressure stabilization

 balls serve to penetrate fractures and prevent closing of fractures

 Thickener, gels: cellulose derivatives, starch derivatives, guar gum,

 swelling and increase of viscosity of the fluids to improve the transport of proppants

Additional anorganic and organic additives:

Surfactants, pH-buffer, biocides, stabilisers, anti-corrosion agents, …

(composition on demand)

Problems: Toxicity of additives, management of waste fluids, environmental impacts

(up to 80% of fluid remain in the rock –> impact on ground water?)

18
Q

What is bad about fracking fluids?

A

Expected impacts on environment Mainly by fracking fluids

 Several chemicals of fracking fluids are toxic or mutagenic

 Portions of chemicals rest in rock (return flow: 20 - 80%)

 Fracking fluids may upwell through fractures into the ground water

 Return flows may contain additional harmful substances released from the rock (e.g.radioactive elements or heavy metals)

 USA: storage of return flows usually in open ponds  evaporation of volatile organic

chemicals (VOC)

 Accidents (e.g. on transportation of chemicals)

Additional impacts

 Earthquakes caused by fracking ?

 Land use (drilling an recovery devices, ponds

for fresh water and return flows, …)

 Demand of agricultural areas for production of

thickeners (cellulose, guar gum, starch,…)

19
Q

What are the characteristics of shale gas?

A

 Maximum output within the first year

 Output reductionreduction by 90% after2 years

 Ouput reduction isdue to narrowing offractures

 increasingof viscosity and reducedoil flow

 Maximum expected recovery by fracking: 3 - 10 % of crude oil

20
Q

Characteristic of Oil from sands

A

• „Oil sands“ consist of sand particles covered by thin water layer

surrounded by a highly viscous oil layer (bitumen).

  • Bitumen content of sands: up to 18 %
  • Major reservoirs located in Canada (Alberta) and Venezuela

(Orinoco)

• Recovery by open-cast mining (e.g. Alberta, Canada) or in-situ

(subterranean reservoirs)

Open-cast mining

Bild: Managermagazin

  • Removal of the ground covering
  • Open-cast mining using excavators ( ~ 70 m depth)
  • Transportation of the sand to the recovery plant
  • Oil recovery in extraction plants:

2 Mg oil sand  ~ 1 barrel oil

21
Q

Processing of oil sands in the recovery plants Steps?

A

1, Milling of the sand

2, Extraction using (alkaline) hot water

3, Flotation to separate bitumen and sand:

  • Adhesion of bitumen to the ascending air bubbles
  • Bitumen containing foam floats on the fluid surface where it is collected andskimmed
  • The sand remains on the bottom of the flotation unit

4, Separation of bitumen and water/salts by solvents

5, Upgrading of the oil („syncrude“) by refining or blending with light oil

6, Waste treatement and recycling

  • Clarification of waste water in settling ponds  skimming or microbial digestion of residual oil  recycling of clarified water
  • Use of sand for land recultivation or land filling
22
Q

How bad are oil sands?

A

Impacts on environment

• Open-cast mining: removal and damage of ground covering 

recultivation required

• High water demand for oil sand processing (~ 3-6 barrel

water/barrel Öl)  negativ impact on local aquatic eco-systems

• Waste water cannot be released to natural water systems 

settling ponds required  danger of leackage and contamination

of local eco-systems

  • Evaporation of volatile crude oil compounds from the ponds
  • Impact on human health under dicussion
  • Enhanced GHG-emissions:

5% of Canadian GHG – emissions in 2008 caused by oil sand

treatment

23
Q

What are the characteristics of mineral oil?

A
24
Q

Give the steps of mineral oil processing

A

Crude oil rerfinery

1. primary refining

  • Atmospheric distillation
  • Residues:

vakuum destillation

2. secondary refining

  • hydrotreating
  • katalytic reformierung
  • isomerisation
  • cracking
  • alkylation
25
Q

Give some refinery products:

A

Liquified petrol gas (~ 3%)

• ethane, propane, butane

Petrol 30-200°C (~ 35%)

  • naphtha -> industrial chemistry
  • petrol (gasoline) (~25%)

Middle destillate 150-390°C (~ 25%)

  • kerosene for aeroplanes
  • diesel fuel
  • light fuel oil

Additional products

  • heavy fuel oil
  • bitumen
  • lubricants
  • waxes
  • sulfur (from Claus-process)

-> 5-10% internal consumption of refinery

-> ca. 2/3 products for energy use

26
Q

Give the characteristics of Gasoline:

A
27
Q

Give the characteristics of diesel fuel

A
28
Q

Give the characteristics of:

  • Kerosene
  • Marine diesel
  • Liquified petrol gas
A
29
Q

What are the exisitng fuels in Germany?

A

 Petrol

 Diesel

 Biodiesel (mainly blends with diesel)

 Bioethanol (mainly blends with petrol)

 Synthetic fuel blends, for example: “V-Power”, “Ultimate”

 Natural gas / (biomethane)

 Liquified petrol gas (LPG)

Germany: blending of petrol and diesel with bioethanol and

biodiesel according to the biofuel quota law

30
Q

Which are 1.s 2nd and x- Generation biofuels?

A
31
Q

Give the following yields for sugar crops, starch crops and lgnocellulose:

  • Average crop yield [Mg / ha*a]
  • Ethanol yield per Mg feedstock [Liter / Mg]
  • Ethanol yield per ha [Liter/ ha*a]
A
32
Q
A
33
Q

Which are the steps of the starch crops processing, define the inputs and outputs for each step? draw a graph!

A
  1. Milling
  2. Liquefaction
  3. Saccharification
  4. Fermentation
  5. Distillation
  6. Redification
  7. Separation
  8. Concentration
  9. Drying
34
Q

What is the enzymatic hydrolysis of starch?

A
35
Q

Lignocellulosic biomass

Give the major components of the following Lignocellulosic biomassfeedstocks

A

Cellulose, hemicellulose, lignin

36
Q

Characteristics of processing of lignocellulosic biomass!

A
37
Q

Processing 2.gen bioethanol steps are:

Draw the energy balance of the swedish SEKAB biomass plant

A
38
Q

What are the potentials and major hurdles of the processing of lignocellulosic biomass

A
39
Q

What are Flexible fuel vehicles“ FFV?

A

Otto-cycle-engines for the operation of varying fuel blends  FFV

While in Otto-cycle-engines without modifications: ethanol blends up to max. 10% (E10), FFV engines for the operation of gasoline/ethanol blends up to 85% (E85)

  • Adopted fuel tank and fuel system
  • Electronic fuel sensors

–> electronic control of ignition, fuel/air ratio and fuel injection

–> Engine power improved by ethanol

–> Reduced emissions (dust, CO), depending on the blending grade

E85 – Flexible fuel vehicles

  • mainly in USA, Brazil and Sweden
  • market launch in Germany since 2005
40
Q

In a table summarize the characteristics of fuels and blends, technical limitations an properties:

A
41
Q
A

SS17_I: Bioenergy Technology (13 decks)

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