Biodiesel Production Technologies-VanGerpen 2p Presentation

7/21/2019 Biodiesel Production Technologies-VanGerpen 2p Presentation

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Biodiesel Production Technologies

Jon Van GerpenUniversity of Idaho

Dept. of Biological and Agricultural Engineering

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*onvg+uidaho.edu

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Types of Biodiesel Production

Processes Definition and standards

Transesterification

2atty acid chains 3tandard recipes

4o-peting reactions

Process issues



Definition of 5Biodiesel6

Biodiesel 7 a fuel co-prised of -ono&al8yl

esters of long chain fatty acids derived fro-

vegetale oils or ani-al fats0 designatedB )"".

Biodiesel -ust -eet the specifications of

A3T9 D /'%)



A3T9 D /'%)&"!Property 9ethod :i-its Units

2lash point0 closed cup D (; );" -in < 4=ater and sedi-ent D !'"( "."%" -a> ? volu-e

@ine-atic viscosity0 1" < 4 D 11% ).( 7 /." --!s

3ulfated ash D #'1 "."!" -a> t. ?

Total 3ulfur D %1%; "."% -a> t. ?

4opper strip corrosion D );" ,o. ; -a>

4etane nu-er D /); 1' -in

4loud point D !%"" Ceport to custo-er < 4

4aron residue D 1%;" "."%" -a> t. ?

Acid nu-er D //1 ".#" -a> -g @g

2ree glycerin D /%#1 "."!" t. ?

Total glycerin D /%#1 ".!1" t. ?

Phosphorus D 1(%) "."")" t. ?

Vacuu- distillation end point D ))/" ;/" <4 -a>0 atT&("

? distilled



Transesterification

D D

FF FF4E! & D & 4 & C ) 4E; & D & 4 & C )

FF D D 4E! & DE

F FF FF F4E & D & 4 & C ! G ; 4E;DE HI 4E; & D & 4 & C ! G 4E & DE

F @DE$ FF D D 4E! & DE

F FF FF4E! & D & 4 & C ; 4E; & D & 4 & C ;

Triglyceride -ethanol -i>ture of fatty esters glycerin



Triglyceride 3ources

Cendered ani-al fats eef tallo0 lard

Vegetale oils soyean0 canola0 pal-0 etc.

4hic8en fat Cendered greases yello grease -ultiple

sources$

Cecovered -aterials ron grease0 soapstoc80

etc.



3tandard Cecipe

100 lb oil + 21.71 lb methanol

→ 100.45 lb biodiesel + 10.40 lbglycerol + 10.86 lb XS methanol

Plus ) l of ,a catalyst



4o-peting Ceactions

2ree fatty acids are a potential conta-inant

of oils and fats.

FF

& 4 & C

Carboxylic Acid (R is a carbon chain)

FF

& 4 & 4!$' 4H44!$'4;

Oleic Acid



!! + "#

# $ % $ 4!$

' 4H44

!$

'4

;

Oleic Acid Potassium Hydroxide

!!

→ " + $ $ % $ 4!$

' 4H44

!$

'4

;

!

Potassium oleate (soap) Water

2atty acids react ith al8alicatalyst to for- soap.



=ater is also a prole-

=ater hydrolyKes fats to for- free fatty acids0

hich then for- soap.

FF4! & & 4 & C ) 4; &

F F

F F

F FF F FF FF

4 & & 4 & C ! ! 4; & & 4 & C ! & 4&C )

F FF F F FF F FF

4! & & 4 & C ; 4; & & 4 & C ;

Triglyceride Water Diglyceride Fatty acid



3oap

3oaps can gel at a-ient te-perature

causing the the entire product -i>ture to

for- a se-i&solid -ass. 3oaps can cause prole-s ith glycerol

separation and ashing.



Process Issues

2eedstoc8 reLuire-ents

Ceaction ti-e

4ontinuous vs. atch processing Processing lo Luality feedstoc8s

Product Luality

Developing process options



2eedstoc8s Used in Biodiesel

Production Triglygeride or fats and oils e.g. )"" 8g soyeanoil$ 7 vegetale oils0 ani-al fats0 greases0soapstoc80 etc.

Pri-ary alcohol e.g. )" 8g -ethanol$ 7 -ethanolor ethanol 11? -ore ethanol is reLuired forreaction$

4atalyst e.g. ".;7)." 8g sodiu- hydro>ide$

,eutraliKer e.g. ".!% 8g sulfuric or hydrochloricacid$



Ceaction ti-e

Transesterification reaction ill proceed at a-ient'"<2$ te-peratures ut needs 1&# hours to reachco-pletion.

Ceaction ti-e can e shortened to !&1 hours at)"%<2 and )&! hours at )1"<2.

igher te-peratures ill decrease reaction ti-es utreLuire pressure vessels ecause -ethanol oils at

)1#<2 /%<4$. igh shear -i>ing and use of cosolvents have een

proposed to accelerate reaction.



Batch vs 4ontinuous 2lo

Batch is etter suited to s-aller plants M) -illiongallonsyr$.

Batch does not reLuire !1' operation.

Batch provides greater fle>iility to tune processto feedstoc8 variations.

4ontinuous allos use of high&volu-e separationsyste-s centrifuges$ hich greatly increasethroughput.

yrid syste-s are possile.



yrid Batch4ontinuous

Base 4atalyKed Process

Ester

TG

Alcohol

TG

Alcohol

4atalyst

Ester

Biodiesel 9i>er

Glycerol

Decanter

43TC ) 43TC !

Glycerol

Alcohol

Alcohol =ater

=ater

Dryer

=ash =ater

Acid

4rude

Glycerol



Processing Lower Qality

Feedstoc!sBiodiesel feedstoc8s vary in the a-ount of free fatty acidsthey contain

Cefined vegetale oils M "."%?

4rude soyean oil ".;&".'? Cestaurant aste grease !&'?

Ani-al fat %&;"?

Trap grease '%&)""?

Price decreases as 22As increase ut processing de-andsincrease0 also.

,ot suitale for high 22A feeds ecause of soap for-ation.



Preferred -ethod for igh 22A

feeds Acid catalysis folloed y ase catalysis

). Use acid catalysis for conversion of 22As to

-ethyl esters0 until 22A M ".%?. 7 Acid esterification of 22A is fast ) hour$ ut acid&

catalyKed transesterification is slo ! days at /"<4$.

7 =ater for-ation y

22A -ethanol HH -ethyl ester ater can e a prole-.

!. Then0 add additional -ethanol and ase catalyst

to transesterify the triglycerides.



Acid 4atalyKed 22A Pretreat 3yste-

i&22A TG Esters

toAcid ase&

process

Alcohol

Acid Ceactor ,eutraliKe

3eparate

=ater 9ethanol

recovery



Product Nuality

Product Luality is i-portant 7 -oderndiesel engines are very sensitive to fuel.

It is not iodiesel until it -eets A3T9D/'%).

4ritical properties are total glycerolco-pleteness of reaction$ and acid value

fuel deterioration$. Ceaction -ust e(#? co-plete.



De"elo#ing Process O#tions 3che-es for accelerating the reaction

7 3upercritical -ethanol

7 igh shear -i>ing 7 4osolvents Bio>$

3olid heterogeneous$ catalysts

7 4atalyst reuse 7 Easier glycerol clean&up



3u--ary

Biodiesel is an alternative fuel for dieselengines that can e -ade fro- virtually anyoil or fat feedstoc8.

The technology choice is a function ofdesired capacity0 feedstoc8 type and Luality0alcohol recovery0 and catalyst recovery.

9aintaining product Luality is essential forthe groth of the iodiesel industry.

Documents

Biodiesel Production Technologies-VanGerpen 2p Presentation