BSE 367 Biomass pt2

To maximize the amount of liquid oil produced during thermal degradation, the following conditions should be met.

Temperature around 600C, fast heat rate

Which two places are responsible for the most biodiesel production?

The EU and US are responsible for more than half of global biodiesel output with rapeseed and palm oil the two primary feedstock in the EU and soybean oil the predominant feedstock in the US

Where does biomass energy come from?

The sun turns the energy into chemical energy via photsynthesis

What are the basic requirements to make biomass?

solar insolation precipitation nutrients co2 temperature

pelleting produces ____

solid fuel

Gasification produces ___

syngas

During the pyrolysis process some components are syngas, biochar, and inorganics. What can these be used for?

syngas- burning for heat biochar- a soil amendment inorganics- fertilizer

Biomass combustion belongs to which family of bioenergy conversions?

thermal conversion

What us the most common failure of AD ?

toxicity - digest can stop producing gas if there is too much of a compund or toxic substance

Characteristics of C4 plants

- are slightly different in their photosynthesis pathway, and what that allows them is to use -- need a lot of sunlight but less water than C3 plants -They have typically very high starch and simple sugar content andunfortunately have higher lignin content than C3 plants -they typically can grow in places where there's lots of sunlight, they have higher dry matter yield than C3 plants, and these typically are bioenergy crops that we consider -Corn, sugarcane, switchgrass, and sorghum. So, we're typically looking at C4 plants when we're thinking of lignal cellulosic biomass for biofuels

Advantages of pyrolysis

- carbon neutral -utilizes a lot of waste - converts low energy biomass to high energy fuel

What are pros and cons of using lignocelluloses

- difficult to convert needs special enzymes microorganism -not being used as food - Cellulose --> hemicellulose--> lignin

What can we use biomass combustion systems for?

- drying industrial processes - space heating - generating electricity (steam turbine power plant) -stirling engine -district heat and power

What are the pros and cons of using starches, sugars, and oils ?

- easily metabolized - easily converted to bioproducts (soy diesel ethanol) -susceptible to degradation during storage - it can be food

AD benefits

- energy production - waste treatment -GHG mitigation -Byproducts generation -reduce odors -destroy pathogens

Characteristics of C3 Plants

- makes up 95% of all plants - has pretty high protein and lipid oil content -It's good for cool and wet climates, and unfortunately -yield is not as good as the C4 plants. - wheat soybeans alfalfa sunflowers trees

storage issues

- may be needed for up to 11 months - piles can cause fires from anaerobic bacteria -microbial degradation

Feedstock logistic challenges include

- moisture content - energy density -inefficient equipment - Quality characyeristics are variable and inconsistent -expensive transport and can strain exisiting networks

Major features of Pyrolysis

- no oxygen - temp and heating needs careful control -small particles and uniform distribution is ideal

How to improve storage

- pack tightly limit oxygen - promote fermentation (lactic acid) - dry materials reduce moisture!

What are the various uses of vehicles to transport biomass and what are there pros/cons?

- trailer/wagon- used for short distances - trucks - field to storage , storage to biorefinery - trains- more efficient and less costly than trucks not an option for field to storage -barges- most expensive to lad cheapest per mile , limited to major rivers lakes, oceans (water bodies only) not likely for biomass - pipelines -.. high capital cost , lowest operational costs , water used as carrier so moisture content must not matter

After cleaning syngas we can now use it. How can we use it ?

- we can use hydrogen in hydrogen fuel cells - catalyze CO and H to make hydrocarbons - Replace natural gas - upgrade it to a lot of different fuels and chemicals

solar energy that's being converted and stored in biomass is not efficient less than __ % is actually converted

1

What makes up biomass used in AD

1. 50% water 2. ash 3. inorganic material / nonvolatile solids (fixed carbon) 4. volatile biodegradable solids

What are the 4 steps of AD

1. Hydrolysis- breaking down polymers into molymers or amino acids and sugars 2. acidogenesis- turning sugars and amino acids into volatile fatty acids 3. acetogenesis - bacteria produces acetates 4. Methanogenesis- biogas

What are the three main methods used for thermal conversion ?

1. combustion 2. gasification 3. pyrolysis and hydrothermal

order the processes in order of which has the most air 1- most 3-least combustion gasification pyrolysis

1. combustion (excess) 2. gasification (partial air) 3. pyroloysis (lack of air)

How do you make algae biofuel

1. grow algae 2.starve it of nutrients 3. break it open 4. use solvents to separate fats and sugars 5.evaporate solvent 6. transform fat to biodiesel 7.biodiesel

4 steps of solid fuel combustion

1. heating and then drying 2. pyrolysis 3.flaming and combustion 4. char combustion

Steps into making biodiesel

1. methoxide preparation 2. transesterification 3.glycerol separation 4.water washing 5. drying

6 steps in pellet production process

1. size reduction 2. drying 3. preconditioning 4. densification 5. cooling and fines removal 6. bagging

Rank the following feedstocks from easiest (= 1) to most difficult (= 4) to produce ethanol from? Think about the steps employed and how recalcitrant (difficult to break down) the material is. Sucrose from sugar cane Cellulose from wood Starch from corn Cellulose from switchgrass

1. sucrose 2. corn starch 3. switchgrass 4.wood

What are some process parameters that can alter the AD outcome?

1. temperature- different kinds of microorganism will from in various temperatures 2. retention time - matching your digester and your feedstock to the right amount of time 3. good mixing

for every 100 lbs of biodiesel you get

10 lbs of glycerol

Biomass residues and waste provide ___% of the worlds energy

14 (mostly from developing countries using wood)

What is the typical temperature range of combustion?

235-2000c , in reality usually 100c or lower

What is the ideal temperature condition and speed that is usually used for pyrolysis?

600-650 c and fast (under 5 sec) to produce biooil

Which two species of plants are able to fix nitrogen ? What is the benefit of growing these plants in comparison with other crops?

Alfalfa and Soybeans These plants don't require extra nitrogen which is great because it is very energy intensive and can gass off to form nitrous oxide a very strong GHG. So removing nitrogen from the equation reduces these risks.

What is Anaerobic Digestion?

Anaerobic Digestion (AD) is a biological process that breaks down organic materials (feedstocks) in the absence of oxygen (anaerobic conditions) producing methane (CH4) and carbon dioxide (CO2) mixture, referred to as (biogas), in addition to the residual sludge (digestate)

Pyrolysis produces ___

Biochar and Bio-oil

AD produces ______

Biogas

What is the economic key to make bio fuels economically feasible?

Biomass logistics

What are the byproducts associated with incomplete combustion?

CO, CO2, H20 and C, metaALS we will always have CO2 H20 and heat but with incomplete combustion we don't process all of the oxygen so we get some C and CO

The highest solar insolation occurs in the Southwestern USA while, the highest rainfall occurs in the Southeastern USA. Which of The following regions produces the most biomass per hectare?

Central plains region where good solar insolation and good rainfall over lap

Where is the most rain in the US?

East

Bio-oil is processed in the way the crude petro oil is

False

Pyrolysis is exothermic T or F?

False, its endothermic

Which biomass crop has the highest conversion efficiency?

Green Algae followed by sugar cane and then corn

Why is bio-oil upgrading very challenging?

High acid content,,,, high water content , instability oxidatively and thermally

Where can you grow algae ?

In ponds and in photobioreactors (pbrs) (like the beer)

Whats the problem with increasing nutrients in the ag sector?

Intensive cropping (like corn) involves heavy use of phosphorus ,a mined resource, which has limited supply which can run out

What are benefits of torrefaction?

It works very well to retain energy 10% energy loss only makes it lighter anaerobic environment Hydrophobic 50% higher density than OG pelleting

in biodiesel stoichiometry we typically add more alcohol than needed in support of

Le chatelier's principle

What are the big three nutrients needed to grow biomass

Nitrogen, phosphorus in the form of P2O5, and potassium in K2O

If you wanted to produce energy from the sun would you use PV or biomass?

Pv is more efficient but biomass is cheaper and we also need oxygen.

Where is the best solar insulation is US? How does this compare to other RES resources?

SW, making it the most useful for PV but we must not forget that we also need rain for biomass.

AD is a mature technology

True

During the winter is important to have low viscosity to prevent freezing inside engines .

True

Who are the largest producers of ethanol in the world?

USA followed by brazil

What are furnaces?

Ways to provide a controlled environment for combustion

In pyrolysis the temperature we run the reactor and how fast we heat the biomass will change the product distribution. What happens if we heat up really fast at very high temperatures?

We will not make liquid and instead produce a lot of gas called gasification

Fixed bed combustion

a furnace that is realtively cheap and can handle many different fuels. They lack efficiency and don't control combustion well enough to prevent air pollution Examples include : pile combustion stroker grate systems stroker biomass feed- fancy version

Whats torrefaction?

a thermal conversion pretreatment where we just lightly char the material, basically 200 degrees to 300, no oxygen, and you make the material much moreeasily broken up very similar to charcoal processing

What is the limiting factor of thermal conversion?

air (oxygen) and heat

What is a cetane number

an indication of how good a fuel is for an engine higher numbers indicate ease of ignition and thus are preferable

Why is there so much interest in ethanol

because it acceptable energy density for transportation

AD produces what two things?

biogas and digestate

What are the three platforms of bioenergy conversion ?

biological,chemical, and thernmal

Gasification process

biomass--> drying-->pyrolysis-->combustion-->reduction

What are the byproducts of combustion?

co2, h20 , heat (complete) , soot char, metals

AD has high capital costs. Why is this ?

construction and equipment is expensive

What does decreasing the level of saturation do?

decrease the viscosity

How can we cut down transport costs and increase energy density ?

densification using cubing, pelleting, briquette

In anaerobic digesters, Hydraulic Retention Time (HRT) of the substrate can be defined as the

digester volume divided by feedstock flow rate

What can biogas be used for?

electricity generation chp generator compression/ liquefaction feeding into natural gas lines fueling vehicles

What are some of the present microorganisms that can be used in AD?

fermentative bacteria h2 producing aceto bacteria h2 consuming aceto bacteria co2 reducing methanogen aceticlastic methanogens

Most common reactor for pyrolysis

fluidized bed pyrolyzer

What are some ways we can make biodiesel more compatible in cold water?

for temperatures between 20-40 degrees F it is recommended to switch to a 50/50 biodiesel diesel hybrid for temperatures below 20 it is recommended to switch to 20% biodiesel and 80% diesel

Dust fire combustion

fuel is fired as small particles which combust while they are fed into the boiler similar to pulverized coal high boiler eff. needs lots of pretreatment

In pyrolysis we are going after a bio-oil in gasification we are going after a _________.

gas fuel product (syngas)

What is the environmental benefit of AD

if we don't use AD some waste products (manure) will decompose into methane .

What does increasing temperature in an anaerobic digester do?

it increases digestion rate because a different community of microorganism become active

Why hasn't advanced fuel taken off yet?

low petroleum and natural gas prices.

fluidized bed combustion

makes biomass into a fluid state - costs a lot - needs cleaner biomass -initial install and maint. can be high

What is biomass?

organic matter intended for fuel or feedstocks into a fuel production process.

What is the main difference between petrol engines and diesel engines?

petrol relies on spark combustion while diesel relies on compression

What we can do to help break down the biomass before we go for further processing

preprocessing using additives : sulfuric acid formic acid lime CaO Ozone Nh3 - This helps break down the lignocellulose to make the hemicellulose and cellulose more available for biochemical conversions

What is one of the most common pelletizing machines?

ring die pelletizer

what can digestate be used for?

soil applications because it is nutrient rich has low pathogens drying and pelletization could facilitate transport bedding compost compostable boards

Bioenergy fulfills which renewable energy sector needs better than the renewables energy technologies of solar, wind, or geothermal?

transportation

Palm Oil and then avocado follow most dense feedstock after algae

true

True or false: combustion is exothermic.

true

half of biomass used is AD is comprised of water

true

Bio - oil properties

viscous high water content not like petro too mcuh water HV is not that high can corrode light steels

How pyrolysis works

we apply heat then we decompose polymers which makes hydrocarbons, aromatics , and olefins (10- carbon chain) and thats condensed into a liquid bio oil

Solutions to handling moisture

we can dry it out in the field (field conditioning) the more moisture allowed the larger harvest window the more convenient labor will be

Where does AD naturally occur ?

wildlife bodies of water

Harvest Schedules

woody crops- year round perennial grasses(switch)- few months in summer or fall . possibly over winter or spring but smaller yield . Chemical composition changes makes for different windows in different grasses . agricultural crops and residues- 2-4 week period (most challenging)

After syngas is produced , you have to clean it. What does this mean?

you are removing particulates and tar you can use a gas cyclone to remover the char. Then to clean it further you can put it through a ceramic filter

What are some ways we can upgrade bio-oil?

you can apply physical treatments such as removing char via filtration emulsification with HC for stability fractionation Some chemical treatments include esterification, deoxygenation, thermal cracking for volatile chemicals