so we're very happy to have you them

here with that introduction I'll turn

the floor over to you thank you

great thank you very much and thank you

all for coming it's been a great chance

to come here and meet a lot of you see

some your facilities this is really a

great place to be doing related research

so I'm happy to be able to tell you

about mine for the reduction of carbon

emissions I'm gonna tell you quite a bit

about my research I'll be focusing on a

couple things but I'll tell you in a

moment but I'll try to give you a little

bit of a broader overview as well into

what we work on so before I begin I'd

like to acknowledge a few people

including some of my collaborators at

the University of Wyoming and my current

and former graduate students have worked

on this the work I'm going to show you

and related work and then some of our

funding agencies which is supported this

work including the National Science

Foundation school of energy resources at

the University of Wyoming and the

University of Wyoming more generally so

to give you an outline of what I'm going

to talk about I'm gonna start by talking

about biomass utilization in general

where we are where we're headed and the

different ways in which we interact with

biomass in our lives I'll then talk

about conversion I'm gonna specifically

talk about feedstocks and challenges

I'll then talk about thermal

pretreatment and biomass combustion so

that's the area of my research that are

really going to focus on in this talk

but I'll try to relate it to other

things that we do again to give you a

bit of a broader picture and then a

little bit about our group looking

forward ok so starting by talking about

biomass utilization so biomass is a very

broad term encompasses a wide number of

different materials large categories of

these include wood such as trees forest

residues agricultural crops which could

be dug at dedicated crops I'll talk

about those in a moment as well as

agricultural residues herbaceous crops

such as grasses which can also be

dedicated feedstocks other organic

wastes such as animal manure or sewage

and other materials including algae and

fungus I'll talk a bit about those so we

interact with biomass in a number of

different ways in our day-to-day lives

most significantly looking forward to

the future I'll talk about a moment but

looking at electricity and heat derived

from biomass is a big area poised to

become much but

or household cooking and heating is used

by billions of people worldwide billions

of people use biomass biofuels and

biomass materials which some of you in

this room work on and which I'll talk

about a little bit and then open burning

so these are all you know the first

three are very intentional deliberate

uses of biomass create attentional

interactions but we also interact with

biomass through slash burning through

wildfires and so there were major you

know major questions in those areas but

the big question for our deliberate

interactions with biomass is how can we

tailor these feedstocks and conversion

processes to achieve the desired

conversion efficiency and products so

electricity and heat let's talk a little

bit about where we are and where we're

headed with this so there's small

distributed use of biomass for

electricity and heat currently in the

United States we're talking cumulatively

around 23 gigawatts of capacity over 190

plants so these are very small

installations as compared to say

coal-fired power plants

there's comparable capacity in the EU

although there are some notable examples

of much larger plants specifically run

by drax and these are mostly converted

coal plants so that has major

implications for the fuel that we're

gonna use the handling that's in place

to deal with that fuel and I'll talk

about that during this talk in this map

you can see mapped out here examples of

or locations of biomass installation so

we see a lot on the coasts and we see

some down the center of the US here in

Georgia we'd have a few I my name home

state of Wyoming we don't have any

currently but again these are small

installations so this is poised to

increase however so there's a concept

called bioenergy with carbon capture and

sequestration with which Chris mentioned

and this is a concept outlined really by

the schematic on the bottom left of the

screen so the idea in Beck says we call

it is the final mass grows taking up co2

from the atmosphere we convert it mainly

through combustion producing co2 that

co2 instead of reading returned to the

atmosphere closing that carbon cycle is

instead sequestered into geologic

storage and the net effect of this is

that we're removing co2 from the

atmosphere

now Beck's has been identified as a key

sea

to removal strategy by among other

groups IPCC and the International Energy

Agency has also identified Beck's as

being incredibly important with more

than two Giga tons of co2 needing to be

removed such as by Beck's by mid-century

to keep global temperature rise at below

two degrees C above pre-industrial

levels and so if you look at this plot

on the right this is the schematic by

plus at all from major climate change

showing our historical co2 emissions up

to around twenty ten and then

projections based on our continued

emissions and what you'll see is that in

this RCP 2.6 in order to keep delta T

low we actually need to reach negative

emissions by mid-century and so when the

question becomes how do we reach

negative emissions

well mitigation will only get us so far

so we need to talk about removal and so

that's where Beck's comes into the

picture among many other strategies so

electricity and heat so okay so we can

use biomass in theory to get negative

carbon emissions but there's some major

challenges and potential pitfalls so

among these are the sheer quantities of

biomass needed to meet these they need

to meet the sequestration goals another

issue with biomass unlike say coal which

can be mined in a very centralized

location biomass is quite distributed so

we're talking about forest residues

we're talking about agricultural

residues these are widely distributed

versus the local use that we're seeking

in concentrated power plants there are

concerns about land-use competition loss

of biodiversity the water and nutrient

needs required to cultivate as much

biomass as we would need to meet the

sequestration goals and so if you look

at this table which was compiled from

the do a billion ton report you can see

the current state of biomass utilization

in the US as well as the technical

potential at least as of last year so we

have major categories again those ones

that I talked about forest agricultural

byproducts energy crops other types of

waste organic wastes and you can see our

current use us usage now some of this is

currently for electricity more so heat

but and there's major potential nearly

three to four times as much as what

we're currently using but there's a

caveat this table and that is if you

look at the line

which is energy crops and so currently

there are very few and there's a very

small capacity of energy crops being

grown in the United States but there's

major potential there's just not

currently economic motivation to do so

there's no reason for people to be

putting the time and energy and cost

into growing these energy crops okay so

let's move on to this next category

which is household cooking and heating

so billions of people around the world

currently use biomass for cooking and

heating approximately 41% of households

worldwide use solid fuels these are

typically used in inefficient open fires

and traditional cook stoves which

produce high amounts of CO and other

pollutants which are quite quite

hazardous people's health so in 2010 it

was estimated that over three and a half

million premature deaths resulted due to

indoor and related outdoor air pollution

so this is a huge health hazard and

relatedly a lot of the solid fuel that

people are using is would derive

charcoal and so this leads then to

issues of severe deforestation so there

are many issues associated with this but

as we look to the future future biomass

demands for heating and cooking are only

projected to grow with population so

well you know percentage-wise people may

be decreasing their biomass use is we

have more and more people we're talking

more and more biomass utilization and so

many groups including my group are

looking for potential improvements to

this so many groups are booked to clean

and efficient cookstoves designs so

improving cook stoves while retaining

the traditional features that are

desired my group is looking at the fuel

side of it so looking at engineered

fuels for example alternative fuels

these could include things like at use

of agricultural waste and energy crops

to reduce the burden on forests could

also include engineered fuel designs to

include to improve for example air

recirculation or air circulation around

these fuels improve combustion

efficiency so on the left you see an

example of an improved cookstove this is

exactly the model that we have in my lab

that we use for these studies and in the

hands here you see an example of an

engineered fuel so this is done by an

NGO called carbon routes International

based out of Haiti and what they have

done is they've derived

charcoal replacements from sugarcane

bagasse so from an agricultural waste

and they're working on integrating this

in the market to replace tree derived

charcoal again to reduce that burden and

so my group did a study with carbon

roots international in which we then

expanded that feedstock range to include

dedicated energy crops and so the

question that we asked together with

carbon roots is could we have a

self-sufficient plant that's

economically self-sufficient that can

everything within the system boundary

grow their own biomass harvest chip dry

carbonized mixed with binder Burkett and

packaged and sell to a consumer in a way

that's self-sustaining and profitable

and so to do this we used Monte Carlo

techniques or probability based

simulation and what we found was that

with a nearly 91% certainty the plant

would break even and there was about an

84 percent probability of 23% return on

investment so this was really promising

and it was nice to use a Monte Carlo

type technique because it's not just a

go no-go answer it really gives you a

probability of success or failure okay

so we've talked about a few ways in

which we're using biomass another whole

category poised again to increase is the

derivation of bio derived fuels and

biomass based materials and this is the

concept of the bio refinery so for

example do-e has put significant

emphasis on development and piloting of

for example cellulosic ethanol advanced

biofuels including algae derived fuels

the concept being that you have an

integrated biorefinery concept where you

bring in a feedstock again here we see

you know in this schematic that we have

a wide range of materials going in and

we have a number of different conversion

processes we have biochemical thermo

chemical other types of chemical

processes and then much like a petroleum

refinery we have a bunch of different

products coming out and so what we can

see right away is that first of all this

is a highly complex integrated process

they're gonna be impacts of feedstock

properties on the yields for example of

these different processes and so we have

a lot of considerations when we have a

highly variable input feedstock okay so

now let's go a little bit more into the

conversion the feedstocks themselves and

some challenges that we face and then I

want to talk about how we try to

mitigate those challenges so here's a

flowchart that is it's not a complete

description of all conversion processes

but encompasses pretty well the areas

that both my group works in with my

collaborators and a lot of the major

categories of conversion processes so

you have biomass resources at the top we

have chemical biological and thermal

conversion processes under chemical one

major categories biodiesel production

that's a major product it was seeking

biological conversion is typically to

produce ethanol or biogas although you

see that I've included an arrow over to

thermal thermal conversion and my group

we're using biological conversion as a

pretreatment for thermal conversion I'll

touch on that in a little bit at the end

and then under thermal conversion that's

where we do the majority of our work so

we're looking at for example tour a

faction pyrolysis these are heating in

an inner environment tour affection is a

milder version of pyrolysis at lower

temperatures with the goal of producing

biochar so a concentrated carbon solid

I'll talk quite a bit about that non

condensable species and bio oils

gasification which is largely to produce

a hydrogen and carbon monoxide mixture

called syngas and combustion which is to

produce heat and power so I'm gonna talk

quite a bit about torah' faction as a

pretreatment combustion as a conversion

process and biochar and heat and power

as products during this presentation but

again we're doing work in in most of

these areas and I'll touch on that as we

go on the other idea that I really want

to throw out there is that while I'm

going to be talking about torah' faction

and combustion combustion necessarily is

a process actually encompasses many many

of these well really all of the thermal

processes so if we think about

combustion of a solid fuel we start with

a fresh biomass it undergoes drying at

the undergoes pyrolysis and so there's a

d volatilization this is the first stage

of combustion so there's a default

elation process a pyrolysis process

whereby we produce volatiles in char now

those may burn and I'm going to talk

later on about you know what kinds of

flames the flaming duration what that

means for our combustion process but

they may also escape that combustion

zone that that flame zone and then we

have issues of for example condensation

of formation of aerosol pollutants so

this is a

this is a loan is a quite a complex step

the char that then results after

pyrolysis is then oxidized and produces

come our typical combustion products co

co2 water and other gases so you know as

we're thinking about these different

conversion pathways I think it's

important to understand this especially

in the thermal that these are all really

related and interconnected ok so let's

talk about the feedstocks a little bit

so we look generally my group at

lignocellulosic biomass and the

composition can vary quite a bit

depending on the specific type of

biomass but it generally consists of

cellulose I have a partial diagram of

cellulose there there's a polymer of

glucose units so we see the glucose unit

here linked by glycosidic linkages this

is approximately 25 to even 50 plus

percent of biomass and you can see how

cellulose fits into the whole matrix and

the schematic on the right so we have

cellulose there again is our glucose

units and our glycosidic bonds this

generally Orient's itself into a

cellular excuse me a crystalline

cellulose structure in the single

microfibrils

that cellulose is then encapsulated with

hemicellulose lignin making it a rather

protected structure and those single

microfibrils form a mesh which then

forms the cell wall okay so we see

already that for example if cellulose is

our desired extracted product of biomass

it's already we can see it's hard to get

to so there are issues around this I

mentioned helpmeet hemi cellulose heavy

clay this is also a major component it's

an a morphus polymer of sugar units so

here we can see a couple of the sugar

units identified it is also a

significant component as I mentioned 25

even 50 percent of biomass by weight and

then we have lignin which is a bit

different in that it's a highly aromatic

structure so you can see all of the

aromatic building blocks here and it's

really cross-linked polymers of phenolic

units so there's already you know just

by looking at these structures we can

get a bit of an idea of okay let's say

we pyrolyze these what cuz ifs compounds

do we expect to get well we can see you

know for example especially lignin that

we expect to get a lot of aromatics and

so that again is giving us clues as to

what we're gonna see in terms of

pollutants again major constituent 10

maybe 35% of biomass and so if we look

at these together we see it's a common

feature here which is significant

significant oxygen content in all three

components this from a combustion

standpoint immediately suggests a low

energy density from a you know a large

system standpoint we're starting to

think oh you know low energy density

means we need to move a lot of biomass

to achieve for example a certain firing

rate in a power plant we don't want to

be moving oxygen just like we don't want

to be moving water you know these are

these are not things we can oxidize and

get energetic value out of so oxygen is

a deterrent if we're thinking about it

has a feedstock for production of

chemicals for example or thinking about

pyrolysis well that oxygen translates

into high acidity of our bio oils and

really poor stability so the oxygen is a

big issue so let's look at some

proximate and ultimate analyses of these

components so cellulose hemicellulose

and lignin so a couple things stand out

which I have circled to draw attention

to what is this oxygen content to a

particular cellulose and hemicellulose

we're looking at almost 50 percent

oxygen by weight and some of these

materials which is quite substantial

lignin on the other hand is more

concentrated in carbon and that's

reflected in fixed carbon after

pyrolysis but you know again so we've

got trade-offs we've got pros and cons

of each of these components which ones

do we want to target for a so-called

cleaning up of our feedstock and then

we've got minerals we've got a few other

constituents so we have to consider

minerals potassium chlorine calcium

magnesium phosphorus which I've

highlighted as a major one that we have

spent some time thinking about the

preservation of and sulfur so these are

mobile at different temperatures these

have implications for example catalytic

effects these have implications for

slagging when use in in

boilers for example and then moisture so

as I mentioned we can have a wide range

of moisture 25 to 60 percent free

moisture even if we dry this material

which is a huge energetic loss we have

to put a lot of energy into dry we then

have more water evolved during

dehydration reactions and so even if you

start with a bone-dry feedstock you

could end up to the 12 with 12 to 15% of

water in your bio oil so

a huge consideration okay so let's look

at some proximate analyses here

so I mentioned minerals specifically

well we may think okay you know we can

deal with ash well let's look at a few

of these feedstocks we have pine

Miscanthus which I'm gonna talk a bit

about more about later it's an energy

crop corn stover and agricultural waste

that we study a lot in my lab and rice

husk and rice straw so rice has can Rea

straw are plentiful resources around the

world people have spent some time trying

to figure out the combustion properties

of them however because look at this ash

content these are huge so there's an

enormous amount of ash in rice

byproducts which could cause major

issues so okay so we see that there's a

variation in composition what does this

affect we'll affects everything really

it affects bio oil non condensable gas

and solid char yields it's gonna affect

the specific energy feedstock costs and

emissions associated with moving these

things around as well as the emission

from conversion of them ash slagging

many other issues okay so one of the

things that we've looked at in my group

is we've looked local for resources and

if you've been to Wyoming in the

surrounding region we have a major

problem with bark beetle it's really

reached epidemic proportions it's been

estimated that a hundred thousand trees

fall daily in Wyoming in northern

Colorado just due to bark beetle kill

off and so thought best swaths of our

forests are dead so we looked at is we

looked at okay well there's already a

very great incentive to be cleaning this

up it's dangerous it's dangerous both

for you know people engaging recreation

in our forests but it's also dangerous

from a wildfire standpoint it's a dry

fuel that just you know burns extremely

well and wild fires and it's an economic

deterrent to people coming to Wyoming

it's really a blight on the forests so

what we looked at is could we use the

bark beetle kill could it be collected

and used as a co-firing feedstock in

regional power plants and so to do this

we started by gathering Forest Service

data and using GIS to map out the

location of bark beetle kill and you'll

see in the red is greater than 25

percent mortality the Green is all treed

land and the black which are tiny and

you can sort of see here but are the

coal mines because what we really wanted

to see is

we move this material to coal mines Co

fire it for a reasonable cost and

reasonable emissions and so we

considered a couple of scenarios in our

study a scenario one was within 20 years

the target was to use up all butyl kill

in 160 kilometers and the second

scenario was a 20% Co firing by energy

which is generally considered to be an

upper limit that's feasible without a

significant loss in thermal efficiency

and then we considered an interesting

sub scenario in which the money that

currently goes into cleaning up forest

from the Forest Service which is really

not sufficient investment of funds

already to really solve the epidemic is

instead used to incentivize power plants

to gather and use this material and so

what we found again this is a co-firing

scenario this is not a pure firing

scenario which would change the

economics a bit but we see just in terms

of dollars per tonne of co2 mitigated by

avoiding fossil fuel usage the costs are

really quite reasonable and then when

you add in a subsidy you actually can

make this economically advantageous for

a plant we also have done a lifecycle

assessment to look at the impact of

transportation distance on emissions and

so you know really that the focus of

that study was on looking at local

domestic use of wood for example wood

pellets in the southeastern United

States versus long distance

transportation so more and more there's

going to be emphasis on life cycle

emissions associated with for example

overseas transportation of biomass and

so it's important to account for that

when you're looking at the life cycle

emissions of biomass utilization okay so

I'm gonna talk about thermal

pretreatment and how we've put a lot of

emphasis on this as a way to improve

some of the challenges of biomass

utilization in my group so the first one

I want to talk about is Toro faction so

Toro faction as I said is a mild

pyrolysis it's heating an inert

environment about 200 to 300 C

objectives here are generally to

increase energy density I'm going to

show you some results of that increase

grind ability so handling of biomass is

a major challenge for power plants we

generally want to pulverize so for

example coal is pulverized in many types

of fire power plants biomass raw biomass

is incredibly hard to pulverize it's it

doesn't grind well not very friable we

want to reduce that the water

uptake of biomass so for example if

we're looking to replace coal well how

is coal stored well largely it's stored

outdoor outdoors and piles well but raw

biomass is stored outdoor in some piles

it's gonna rot and so if we can reduce

its water uptake

this will help quite a bit we want to

decrease the oxygen content now that's

goes hand-in-hand with increasing the

energy and energy density but if we

don't even if you know we're not

thinking about burning biomass if we're

thinking about subsequent pyrolysis of

biomass reduction the oxygen content is

going to be advantageous for reducing

the acidity in in the improving the

stability of the bio oils and we want to

disrupt the matrix for further

processing so that I'm gonna show you a

bit of that later but essentially again

this is helping to sort of pre-degree

the biomass and make it more susceptible

to subsequent utilization so not just

for combustion but for a lot of

different subsequent paths and on the

right here you can see a schematic that

shows the temperatures at which those

three major components hemicellulose

lignin and cellulose breakdown so we can

see pretty you know pretty clearly the

hemi cellulose is the first one to go by

the time we reach the top of our torah

faction range we already have extensive

developed elation and carbonization of

our hemi cellulose and i'm going to show

you in a moment that we clearly see it's

gone lignin and cellulose her but more

reluctant to breakdown so not until the

top of that Torah faction range do we

expect to be breaking down our lignin

and our cellulose and I'll show you some

rate data on that a little little bit so

one big area of emphasis is can we model

the mass loss during Torah faction

specifically in my group we'd like to

get to a more detailed mechanism but

because that is so challenging there are

just so many chemical species that are

evolved during thermal conversion of

biomass as common approach taken to this

is a lumped sort of global mechanism so

an example of this is a two-step

first-order mechanism of five pseudo

components so we start with raw biomass

upon initial heating we first break down

the hemi cellulose to produce lumped

volatiles we'll call those volatiles one

we then have an intermediate solid which

we further heat produce to break down

the cellulose and lignin and we produce

a lumped category of volatile volatile -

and then what we're left with is a char

and

these volatiles again are incredibly

complex we analyzed them using gas

chromatography mass spectrometry I'm

going to show you a little bit of

results of that in a bit but some

compounds that we produce acetic acid

formic acid methanol lactic acid Ferol

hydroxy acetone what are we seeing in

here well we're seeing significant

oxygen even the oxygenated compounds

okay and so we can lump these as I said

into ball tiles one ball tiles two and

we can look at the composition of these

and come up with lumped compositions so

volatiles one is generally well

represented by something on the order of

c1h 4.90 3.2 volatiles - you can get a

lumped composition of c1h 2.90 1.1 now

compare that with raw biomass which is

well represented in general by c1h 1.50

0.7 and what you can see very quickly is

we sort of lump you know lumped analysis

of these is that we're proportionately

releasing larger amounts of greater

amounts of hydrogen and oxygen as

compared to the carbon and the material

and now if we keep proceeding to a more

severe form of Tora faction pyrolysis

we're now heating to above 300 scene

that same inner environment and the

objectives here are generally a little

bit different we want to produce bio

oils again those can be turned into

fuels or other chemical precursors or we

may want to produce biochar that may be

the target this can be used as a soil

amendment there's a significant amount

of work going into figuring out whether

or not it has a positive effect on soils

but it's generally been shown that it's

pretty stable in soils for long periods

of time and so now you have a

sequestration pathway via that biochar

you may want to combust the biochar and

you may want to make functional

materials and so we're beginning to do a

bit of that in my lab which I'll talk

about briefly at the end and so again we

can see the pathway here we go through

drying we go through primary pyrolysis

producing water tar permanent gases and

char and then we undergo secondary

reactions which include namely cracking

of the char to produce more gas in this

brews more char and so what's really

important here is we look from primary

to secondary pyrolysis is that the the

opportunity to proceed from primary to

secondary is provided through issues

such as heat and mass transport in

biomass so longer resident

time of these primary volatile products

produces opportunities for secondary

cracking so these are all issues that we

need to be thinking about as we're going

for example from a pulverized fuel to

larger sort of need of biomass

constructs okay so let's look at some

results to kind of show this in action

so in the picture on the top right I

like this picture because it shows a

sort of what our material looks like as

we proceed these are actually pictures

of elephant grass so in pan one we have

a raw elephant grass kind of looks like

what we'd expect from a weed growth

Reedy grass pan 2 is a late Tora faction

so it's kind of a caramel color and then

pan 3 we've fully torrefied this at 300c

and you know what's starting to look

like a charcoal this is really what we

expect to see now what I'm showing here

is called the Bank revelon diagram on

the x-axis is the oxygen to carbon ratio

on the y-axis is the hydrogen to carbon

ratio and in the top right here we have

our raw this is for pine we have raw

pine and pine torrefied at 200 and 250 C

and what we can see is that ok we don't

get a significant change in these ratios

not very substantial at that point but

as we proceed to higher temperatures we

pretty quickly get a decrease in our

hydrogen to carbon in our oxygen -

carbon ratios as we proceed to pyrolysis

temperatures of in this case within 2

for ADC we jump right over this filled

circle which is our Powder River Basin

coal a very high volume coal produced in

Wyoming so we actually get a carbon

intensification that exceeds that of

coal and relatedly of course a

significant reduction in hydrogen and

oxygen content and so we looked at for

example the heating values of these

fuels as they're torrefied and pyrolyzed

and what we can see here is that as

compared to raw well but when we

pyrolyze we have an over 40% increase in

the heating value and we actually have a

higher heating value material than even

our coal for comparison and as we're

thinking about the importance of this is

major implications for transportation so

if we want to move a certain amount of

energy and feedstock we now have you

know a way denser fuel in terms of

energy content that we can be moving

okay so we're not just interested in

what happens as a fun

temperature you know we can see which we

can see clearly here on the x-axis is

time and hours on the y-axis is mass

loss and I'm showing here time profiles

mass loss profiles for 250 275 and 300 C

and what you can see is the number one

there's a significant time component

we're gonna talk about that in a moment

but of course there's also a significant

temperature factor here in terms of the

rates of mass loss if we were to carry

this out to very long times you know

they were of 20 hours we would actually

see that these mass losses reach about

the same extent which is really

interesting because again there's a huge

rate component going on here and so we

looked at the evolution of heating value

with time so on the x axis again is tour

affection time this time in minutes on

the y axis is heating value in mega

joules per kilogram and so you can see

as compared to our raw material starting

out about 17 and a half mega joules per

kilogram we increase pretty dramatically

here with time to 17 percent or excuse

me a seven percent increase at 15

minutes 15 percent increase at 30

minutes

20 percent in an hour and up to 25

percent at 3 hours and so the time

dependence here is starting to give us

the impression that there's an

optimization issue because you know we

probably don't want to be Tora fiying a

batch of material for 3 hours what's the

optimal time and there are many many

factors that fit into that decision and

I'm going to present a few of them to

you so we've developed a model that

predicts energy yield and heating value

enhancement using a very simple

technique one that could actually be

implemented in industry with minimal

inputs so as a function of mass loss

using only proximate analysis and raw

biomass heating value you can determine

what the energy yield is of your biomass

so pretty simple you know running model

and we can see pretty good results with

the current model so again we on the

x-axis this fraction of volatile matter

release so that's the extent of Tora

faction this is readily measured so for

example in a laboratory with some pretty

simple tools you can measure that I'm

the primary y-axis is the ratio of

heating values between your dry ash free

torrefied biomass and your dry ash free

raw biomass and on the secondary y-axis

is the percent of energy retained

and now this starts to give us a

different you know angle on the and the

issue because not we're not only

increasing our energy density which

we've already seen is we horrify and we

lose mass but we're also losing a

significant amount of our original

energy content so again there's a

balance here you know we're losing a lot

of energy and yet we're also densifying

so there's a trade-off so I mentioned

the rate issue so what we're very

interested in is can we start to

elucidate rates of Torah faction and

then of subsequently of pyrolysis under

conditions of either a function of time

or a function of heat and mass transfer

limitations and so this is just an

example of our GCMs results on the

y-axis

arrghh excuse me on the x-axis is time

and on the y-axis just the ion count and

so in Peaks 1 to 13 okay we don't see a

lot of change in time these are bio oils

collected from tour affection of

Miscanthus grass again as a function of

time okay so with time we don't see

major changes in those Peaks but I've

highlighted two peaks glucopyranose and

phallic acid that we do see evolving in

production in time these are great

markers for the breakdown of cellulose

and lignin and so we're able to see is

in a very time resolves way we're able

to quantify some of these breakdown

products this gives us a lot of insight

into what's breaking down quickly

there's a lot of great evidence the hemi

cellulose breaks down very quickly but

what's breaking down slowly and at what

rates will we can start to really

elucidate cellulose and lignin and then

we can start to compare to existing

models develop different models okay so

we're talking we've talked about heating

value we've talked about evolution of

species let's think a little bit about

other issues that we have with biomass

when we're thinking about widespread

utilization and one of those is handling

so I mentioned the fact that biomass

doesn't handle well it doesn't grind

well well Tora faction has an advantage

of making material more friable or more

readily ground so what we do in the lab

is it's pretty simple we just mill a

sample in a ball mill and we sieve into

size fractions before and after milling

to assess the grind ability and what I'm

showing you here is just an average

particle size so this is some of the

work that we did looking at bark beetle

killed pine and healthy pine

each torrefied at 200 250 and 300 C and

you can see pretty quickly shown here as

a temperature dependence of particle

size reduction so as we increase the

torah' faction temperature we decrease

particle size pretty significantly now

in contrast here well I should say

adding more to the picture is again the

time dependence we're really interested

in this time dependence so that we can

attempt to optimize the process so

here's the time dependence looking at

Quora faction in nitrogen and co2 so a

lot of laboratory studies have looked at

Tora faction in just a nitrogen

environment we wanted to expand that

into a co2 environment to start looking

at many practical considerations of you

know for example to refining combustion

gas so again time dependence point to

five point five one and three hours and

what what stands out to us very very

quickly is that regardless of the gas

environment even at fifteen minutes we

get a significant reduction in particle

size after grinding even more

significant is that we don't see

additional significant yield or gains

and grind ability with further time this

suggests two things to us number one we

can achieve one of our objectives which

is improve grind ability in a very short

processing time but also it suggests to

us taken together with all of the other

information that Hemi cellulose is

really one of the big deterring factors

it's really one of the very resistant

factors to grinding so if we can remove

that Hemi cellulose which we know is

gone by 15 minutes into tor faction we

can improve the grind ability that's a

pretty valuable piece of information

okay so we've pre treated this material

we've turned it into a more friable

higher energy density more carbon

intensified material well now what do we

do with it as I mentioned before we

could take it in a lot of different

directions the one that my group likes

to focus on is combustion one of the

ones we like to focus on I should say

okay so Tora faction then is a

combustion pretreatment so one of the

first tools that we'll use if we're

looking at a mid combustion of a

material is called the thermal

gravimetric analyzer or TGA and so TGA

is a very nice tool I sort of you know

casually described it as a scale and

a furnace because what you can do is you

can prescribe a heating temperature or

heating profile or temperature profile

to a sample and you can study its mass

loss in response and I don't give you a

lot of information and so what we'll do

is we'll do combustion in the TGA so we

introduce air we heat it at a given rate

and we see we want or its mass loss so

when the x-axis is temperature and

degrees C on the y-axis is derivative

mass loss in percent per minute and the

first one I want to draw your attention

to is the black line which is coal and

so coal undergoes the same two stage

combustion three stage if you include

drying that all other solid fuels do it

will undergo any volatile ization step

followed by a charc sedation but when we

look at this we see that those two

stages are really quite merged from a

TGA perspective so in other words the

volatiles are evolving late and as the

charr combustion is beginning to take

over okay that's interesting because

then when we compare to biomass we see

very distinct characteristic to stage

combustion so again they're both

undergoing the volatilization followed

by Charak sedation but the volatiles and

biomass evolved earlier so they have a

distinct first stage and then we're left

with that char which then actually

oxidizes a little bit later on so

there's a discrepancy here between the

combustion behavior of biomass

combustion behavior of coal now if we

look at a torrefied biomass at 300 C we

see a couple things the first is that

the volatile peak has reduced a bit so

most notably we call this the Hemi

cellulose shoulder you'll see it a

little more distinctly in the next date

I bring up but we see that the Hemi

cellulose shoulder is gone

okay good indicator that we've lost our

Hemi cellulose we also see that the

second stage combustion is more

significant not too surprising we know

we've intensified the carbon we're

getting more char burnout again we've

looked at this as a function of time and

there's a lot of data on this graph so I

want to point out a couple things to you

in particular so again on the x-axis we

have temperature and degrees C on the y

axis again it's derivative mass loss the

two data sets that I really want draw

your attention to are the black line

this is now for Miscanthus grass and we

can see here you really see the Hemi

cellulose shoulder over on the right

excuse me on the left and then we see us

like a smaller second stage combustion

you know at around

400-450 see the next one I really want

to draw your attention to these are soon

these are again this is our time series

so we're starting torrefied this

material for longer and longer or

monitoring the impacts on combustion

behavior so what we can see is that the

first stage combustion continues to sort

of you know decrease decrease until they

it's a three hours now if you remember

back to the time series of mass loss

three hours is is essentially a complete

mass loss at 300 C and now what we see

is this first stage combustion there's

almost it's almost gone and we have a

very prominent second stage and so it's

really beginning to look more like our

single stage coal combustion okay so

that's that's another data set for us we

may have found great grind ability after

15 minutes at hora faction but what does

the combustion behavior look like well

it still looks a heck of a lot like coal

I've skews me a liberal biomass so we're

not quite there yet from a combustion

standpoint so there are a lot of factors

to consider here okay so we start with

TGA the next step will take us into a

pulverized fuel flame so we really like

this pulverized fuel flow reactor

because it allows us to number of things

allows us to look at rapid heating it

allows us to look at evolved species and

it's very fuel flexible so it gives you

just a very quick overview and the

facility is pretty simple here we've got

a flat flame burner it's very hard to

see because there's a very set time

'center tube through which we can

introduce pulverized fuels of various

sorts could be biomass could be coal

could be fuel blends we have uh solids

pump and a pump controller around that

solid fuel that pulverized fuel flow

will have a co flow flame so we'll

typically use for example a lean methane

flame to provide rapid heating and some

oxidizer and then around that will have

an inert shroud to protect the whole

thing from ambient air and so we'll look

at it so again we'll look at pulverized

fuels but look at the rapid heating that

they undergo and what's nice about this

regime is we have minimal heat and mass

transport limitations due to the small

particle size and the plentiful oxygen

around it and so what you can see on the

right-hand side here is two different

flames so you can see a sub-bituminous

there's a pure B coal I note that it's

sub-bituminous because there's a very

high volatile content and then you can

see a pine biochar that we got from the

National Renewable Energy Lab in

Colorado and right away to the eye you

can see some differences now these are

equivalent and

feed rates but nevertheless for the PRB

you can see a highly luminous region a

generally larger bulbous region in the

bottom here and what I'm going to show

you in a little bit is this is

predominantly due to slip formation in

contrast for the pine biochar remember

for the pine biochar we have very little

volatile content now for the pine

biochar we see a far less luminous

region the lower you know boldest region

in the bottom so we're starting to get

some insights even just from visual

analysis of these flames we are forming

just visually way less foot so does a

very large radiator of energy which I'm

going to show you in a minute and so

we're starting to understand that ok

depending on what the pretreatment is of

our of our biomass it's gonna

potentially have way different radio

radiative properties way different

radiant energy fraction and that's a big

consideration especially as we're

thinking about introduction into power

plants we're thinking about thermal

efficiency we're think about heat

transfer with an boiler the radiative

heat transfer is an incredibly important

property okay so it's another piece of

this puzzle again just you know asking

for optimization so a collaboration that

I have going with a colleague in my

department Michael stole injure is the

comparison of experimental in numerical

work we're really taking a taking great

steps to integrate these two techniques

the experimental numerical allowing the

experimental to inform the numerical

work and vice versa

- and the goal here is to really come up

with highly accurate models to simulate

pulverized fuel combustion and so far to

date we've really been focusing on coal

but we've been refining these techniques

and they would be readily applicable to

other fuels as well

so experimentally I'll give you a little

overview and then I'll talk a little bit

about the numerical side so we use to

quit called two-color pyrometer ii we

essentially view the flame through two

filters two bandpass filters 580 and 685

nanometers in a stationary you know

particle ignition study this would be to

deduce particle temperatures but in a

pulverized fuel flame you have a little

bit of a different situation because

what you see the radiation you receive

on your detector is an integrated path

emission okay so you actually have

emissions from every cross section

within the flame and you're not just

seeing the outer edge you're seeing

everything so what

do in this technique is we actually

individually analyze the individual

channel signal so we're looking at the

580 signal we'll look at the 685 signal

and we'll deduce you know we'll derive

those signals signal profiles now in

contrast what my colleague does with the

numerical simulations is he also

simulates this flame and he comes up

with a simulated signal on a simulated

detector and then through comparison of

these two signals we can understand if

we're capturing the behavior of the

flame well and if we're not then we can

try to you know refine and think about

what the sources of those discrepancies

are and so again I show a little bit of

a just a schematic of how the numerical

integration goes so essentially this

cylinder that I'm showing you the plain

view of is our it's our flame and what

they do is they'll integrate the radiant

emissions from the back of the flame to

the front of the flame and simulate

what's received by the detector and so

what we account for is the emissions

from each cell at our two wavelengths as

well as the absorption by each cell okay

so when we compare these what we find is

really very interesting so on the x-axis

of this plot we have height above burner

so there's our burner height and then

this is the height up through in this

case the coal flame on the y-axis is the

heat flux or the read a flux rather

received by the detector and here are

the signals for the two different ways

these are both numerical results so the

red dots that you see are the signals as

a result of the soot radiation the black

lines that you see which differ

imperceptibly from the red dots are the

emissions due to the soot and the coal

particles okay so what's the major

takeaway here the major takeaway is that

the major emitter is the soot and this

is this is not too surprising really for

a coal flame although it's a you know

been impressive to see the fact that the

coal particles make no difference and

the caveat here of course is that this

is a relatively dilute dilute flame in

terms of particles if we had higher

particle loading we'd expect them to

participate a little bit more but

nevertheless the emissions are

predominantly really dominantly due to

so okay so what's the implication for

this well if I have for example a lower

volatile fuel I'm gonna expect way less

formation

if I availa slip formation I have less

radiative heat transfer so there again

tying all these considerations together

we can't just look at fuel properties we

have to look at their combustion

properties okay so we went a little

further and we tried to compare we

compared the behavior and the magnitudes

and the position of the signals to

understand try to understand again is

our D volatilization model functioning

correctly can we capture char burnout

are these you know how is the numerical

model stacking up against the

experiments and what's really lovely

about these experiments is that they're

nice laminar flow experiments so we can

you know we've done a lot of validation

work to validate that the flow is the

flow regime is correct okay so x-axis is

head above burner again here we have our

heat flux on our simulated detector as

well as our real detector these dotted

more solid lines here are the

experimental profiles and the dashed

lines are the numerical profiles okay so

we see a couple of things first of all

we have a 10-millimeter discrepancy

which is a significant fraction of our

actual liftoff height of our flame the

steep slope increase here is where we

indicate the liftoff height because we

get a lot of radium emissions okay so we

have a significant discrepancy this is

suggesting a problem with our D

volatilization model which is no small

task to try to match to actual volatile

emission or volatile release from a

flame so this is a huge you know this is

a huge area that for potential

improvement so we do have a shift issue

but when we do shift these data we see

that we actually are capturing some

trends pretty well we're capturing the

onset trend we're capturing the

subsequent decrease post peak emissions

so so it's a work in progress we're

trying to now refine the model really

refined that on the numerical side

refine the model and then assess the

predictive capability of the model so

again what's the end goal here is to

have a numerical model that accurately

captures pulverized fuel combustion why

because then we can start to assess for

example large-scale advanced combustion

techniques okay on the experimental side

what we're going to try to do next is

quantify the radiative fraction so we've

already seen comparing coal comparing

pyrolized biomass we've seen just

visually major differences in their

emissions so what we'd like to quantify

what's the radiative fraction difference

why because then we can understand what

the what the various heat transfer

mechanisms are for the heating value

released from the fuel okay and then

collaboratively collaboratively bringing

these together we want to assess the

impacts of fuel and combustion

strategies on thermal efficiency that's

the big picture goal and so as some

initial you know sort of a snapshot of

what this looks like we've looked at

different fuels and we look at their

part just single particle ignition

okay so we'll introduce a particle to a

flame we'll watch what's the ignition

delay time what's the time before that

that homogeneous gas phase flame begins

what's the time until it ends then

what's the char burnout time these are

all very characteristic quantities for a

given fuel and so what I've shown here

just for kind of you know a snapshot of

that is for a few different fuels we

have raw elephant grass 300 C torrefied

elephant grass and 500 C pyrolized

elephant grass and we're comparing that

to pure be coal and on the y axis here

is the volatile flame duration and so

this is as I said you know we watch a

single particle ignite we watch what's

it's volatile flame duration we can

already get some information just from

that alone and perhaps not surprisingly

based on what we've already seen in

terms of how the species are or how the

biomass is evolving with thermal

treatment the raw flame duration and

this is given in seconds per kilojoule

of heating value of the fuel the raw

fuel has a you know high high flame

duration the 300 C is substantially

reduced and by the time we've pyrolyzed

in material to 500 C it really has

negligible volatile matter left such

that we don't see a volatile flame and

again tying this together now with the

results from the numerical simulations

and the radiative fractions we're

starting to get a picture here that if

our for example our boiler or a kiln

relies on radiative heat transfer from

the fuel which many do we're gonna have

a little bit of an issue if we're

introducing pyrolyzed fuels we need to

be accounting for all these things and

just for comparison I have the PRB coal

which is most similarly like the 300 C

okay so looking forward kind of where

we're headed with this again this is

kind of in a snapshot of what we've

looked at so as I mentioned biomass

utilization for energy

really Beks as a concept is really

poised to increase so it's again major

interest in this as a negative emissions

pathway but there are environmental

impacts and we need to look at these

holistically including water demand

energy intensity and emissions

associated with use land use

requirements nutrient depletion and so

the question that we ask is can we

improve thermal efficiency which in

implicitly lowers biomass demand in

terms of how much we have to move at

least so we want to by improving the

feedstock again through all those or the

different knobs that we've looked at or

all the different metrics we want to

lessen a biomass firing penalty and so

typically there's about a 10% reduction

in thermal efficiency operating a plan

on biomass if we can reduce that that

discrepancy again we can lessen the

biomass demand and we really like to

tailor the fuels to reduce

transportation demands and holistically

again as I mentioned in collaboration

with my colleague we want to do all this

to also assess alternative conversion

strategies so for example various

advanced combustion strategies such as

various forms of oxy combustion things

like that okay so as I mentioned again

looking ahead we're looking at

increasing population using biomass for

heating and cooking well we would like

to do with a lot of the insights that

we're already gaining from how biomass

transforms we want to see to reduce

pollutants from cook stoves via the

choice of fuels and pretreatments and so

we're seeking out these more sustainable

fuels we're looking to tailor the

feedstocks again through these thermal

pre treatments that I've talked about as

well as things like briquetting you see

an example of a Burkett here which is

basically a ground-up fuel that's then

been formed into a desirable form for

efficient conversion to improve the

conversion efficiency and reduce the

pollutants and we're very interested in

developing low-cost or faction in

pyrolysis technology that's highly

efficient and khloé as clean as can be

so for example you see some images here

of very low cost pyrolysis for a faction

kilns can we develop those to be both

highly efficient so minimizing energy

losses that are not sought maximizing

our energy yields well being as clean as

possible so essentially the idea being

to be able to roll out the engineering

fuels worldwide for bio fuels and bio

drive materials were seeking these of

course again you know same idea to be

replacing fossil fuels as a feedstock my

group I didn't talk about it here today

much we look at novel conversion routes

for the production of bio derived

chemicals and so one of the avenues that

I'm working on with one of my

collaborators in chemical engineering

is the use of lean oolitic fungi to

pretreat biomass and so we're really

trying to do in this project is

elucidate what the techniques are or

what they excuse me what the influencing

factors are to influence for example

fungi of which I've shown you three

examples here what influences them to

digest for example lignin instead of the

more easily accessible and more

desirable sugars in hemi cellulose and

cellulose and finally my group is

looking at supercritical co2 as a

pretreatment strategy I've been using a

lot of the same concepts that we've been

talking about looking at the evolution

of chemicals looking at the evolution of

morphology what are the impacts of this

on subsequent conversion and so with

that thanks for your attention I'd be

happy to answer any questions

[Applause]

hmm yeah that's a great question so not

directly so my group does do work in

natural gas a lot of our emphasis in

natural gas is on the utilization of

natural gas with higher levels of C 2

plus hydrocarbons which are currently

somewhat challenging to use and are

often the flared components are from the

flared gases so we have not done a lot

of comparison and with biomass

necessarily coal really has been our

target to cover the drop in replacement

for coal but it's a great it's a great

question I mean if we're thinking about

alternatives to biomass natural gas is

absolutely a cleaner burning competitor

so it's a it's a great point to do that

comparison our emphasis though has

really been on a solid fuel replacement

yeah thank you

that's a great question okay so in

especially you know in industrial scale

processes it's often the torah' faction

gas that's evolved during taura faction

is burned to provide the process heat so

this is already a bit of an integrated

process my group doesn't analyze we we

don't for example you know in our techno

economic assessment we have not looked

at the energy intensity of that other

groups have done that but we don't look

at that but there is the important point

that the gases that are evolved during

court or faction can be burned and used

to provide the process heat and the

inert environment so there is an eye

towards already an industry towards you

know improving efficiency and lessening

energy demands that way yeah thank you

yeah that's a great question so in in

specifically the Van Creveling space we

have not done that yet so those were all

at a given you know period of you know

after an hour of tora faction this is

their state and with the exception of

the for a DC power pyrolized material

which was a fast paralyzed so by Enron

so we have not looked at that but that's

exactly where we're going with it so for

example the little bit of GCMs results

that I did show that was a time

resolution then of one of those

snapshots so so if you remember the 300c

was sort of halfway down on the van

kremlin diagram that was the first big

leap and it's that 300c that we have

started to resolve in time and only four

300c so far but that's exactly where we

hope to go is to look at the evolution

of species in time but again for the

300-seat that was where we saw the

suggestions of rapid hemi cellulose

breakdown with negligible additional

breakdown past you know 15 minutes and

then with time we were seeing the

evolution of the cellulose and lignin

breakdown products and so it's just sort

of a snapshot of what we're trying to

resolve and how we're trying to sort of

study that and the next steps for us are

not only to look at the evolution during

tora faction but then okay can we do the

same thing during pyrolysis well sure

you know we can start to look at the

evolution of species during at higher

temperature and pyrolysis then we can

start to look at the impacts of for

example these are all pulverized fuels

but we can start to look at the

evolution of those species at larger and

larger particle sizes as we have heat

and mass secondary reaction so that is

the goal is to sort of you know be

evolving in time and then to look at the

evolution in time with particle size

which introduces whole new issues so

yeah

that that's a great question so I think

the answer to that well there's a

practical answer to that which is that

will we likely will not get all the

biomass we need from one type of biomass

and that's really what that billion ton

report tells us is that we're probably

gonna have a very diverse supply the

results also you know of looking at all

these different biomass types strongly

suggest that we can make them into a

more cinéma similar uniform product

through targeted thermal pretreatment so

I think the answer to that is sort of

number one we may not have a real choice

as to what we have going on what we use

I think the probably the residues and

the AG ways those are gonna be through

the lower hanging fruit as opposed to

you know planning energy crops and in

rolling out significant lots of energy

crops but we'll have to get there

eventually if we're gonna meet our

biomass utilization goal so I think the

answer sorta we have to be able to we

have to be able to be fuel flexible and

adapt to all these different fuel types

and so what are the treatment strategies

that sort of allow us to get there and

Tora faction does in many ways allow us

to sort of converge and I think that's

an important next step is to show that

we can take a variety of different

biomasses and make them perhaps more

uniform to allow for fuel

interchangeability yeah so if we're kind

of for more distributed use yeah and

that's a really interesting question

that we've chatted about a little bit

today even is the idea of more you know

optimization of plant size and

distribution like you say so that you

don't have to move the biomass to the

plant you can move the plant to the

biomass it's a great question I think

some of the issues that come up is the

efficiency of scale I think that's a big

one and the cost with distributing these

systems but yes absolutely and I think

that's that's a that's a real

optimization

that needs to be addressed is I think

you know the numbers show that it's

maybe not feasible to be moving all that

biomass to a centralized location so

what do we do there's actually a plant

in in Portland that did a biomass firing

day so they took their power plan and

they fired it on torrefied biomass and

they had so many issues with just

procuring enough biomass just for one

day of firing they were moving it from

the Southeast United States so you know

they're driving truckloads of biomass up

to Oregon and they just to this point

you know now they've thought about you

know growing their own and trying to

produce their own local supply but but

it's exactly at this point I mean it's

not practical to be moving biomass all

the way across the United States sure

for a demonstration day but not for a

long term so I think that's a great

question