geothermal approach to pet recycling

7/21/2019 Geothermal Approach to PET Recycling

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Index

Introduction to the recycling problem --------------------------------------------------- 3

Problem of Plastics in Per --------------------------------------------------------------- 5

Geothermic potential ----------------------------------------------------------------------- 7

Choosing of PET and method ----------------------------------------------------------- !

"escription of the mechanism ----------------------------------------------------------- #

Geographical location of our plant ----------------------------------------------------- $

%ur concept of the &aste separation plant ------------------------------------------ 7

Conclusions ---------------------------------------------------------------------------------- #

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Introduction to the recycling problem

'ecycling is a problem all o(er the &orld)

People* countries* companies* industries* etcetera* ha(e al&ays been encourage to

recycle* but the social conciousness of this action is really lo&) +o small* that not only &eare &asting materials* money and resources* but &e,re also creating a really bad future for

the follo&ing generations to come)

Climate change is in e(eryone,s mouth) There is in fact social a&areness about the

eistence of this problem* but not enough to actually encourage people to ta.e the ropes

and find a solution or better said* do something for small it is* to sol(e the problem)

/aybe it is because although people .no& about it* they still don,t reali0e the importanceand the effects this has* no&adays and in the future)

1 (ague description of &hat climate change could be ,the transformation of our actual

climate into a hotter one due to C%# produced in the combustion of fossil fuels,

This lea(es many (ariables in the air* but the concept can be any&ays easily caught) This

is &hy rene&able energies are opening their &ay across the mar.et slo&ly but surely* but

this seems to be insufficient) 2hy aren,t &e funding the use of rene&able energies li.e the

eolic or solar ones if they are so harmless and &e,re still using fossil fuels* that not only

they contaminate in a &ay that can affect the &hole planet but also they are limited

2ell* the best ans&er &e,(e come up &ith is the logical one4 money)

Perhaps it,s not profitable for companies to in(est in this .ind of technologies) Perhaps it is

too difficult to create plants that can process this .ind of energies) %r perhaps this is all a

lie &e,re being told and rene&able energies doesn,t eist)

In any of three cases* research in rene&able energies is* by really far* &orth the

in(estment and the effort)

ut climate change is not the only problem)

There are some places in the &orld &ith &hat is .no&n as ,garbage patches,) These

places are made up of small pieces of plastic* (ery tiny ones* that accumulate in different

locations &here currents con(erge and pollute the organism li(ing there* ultimately

affecting us as &e feed on those animals)

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Problem of plastics in Peru

This latinoamerican country* the #!thbiggest country in the &orld* has o(er 3! million

inhabitants* &hich ma.e it the 5 thmost populous country in +outh 1merica)

The epectations regarding its demographic gro&th tell that by #!5!* its population could

reach easily the 5! million barrier)

9o&e(er* the inhabitants distribution is highly heterogeneous* &ith a notorious

concentration in the metropolitan areas ;almost 75 > < of the land=) This characteristicgeografical features are going to be .ey points for the goal of our proect)

?o& it,s time to focus on the main issue &e &ill be treating) The Peru(ian 1mbiental

/inistry published three years ago a detailed report on their solid &aste anual production*

their treatment procesess data and the national needs for the future according to all the

information gathered ;http4@@&&&)redrrss)pe@material@#!$!$#3$5!35)pdf=) 2e &ill be

ta.ing this document as the most reliable source)

+olid &aste production

"uring the year #!#* and al&ays according to the Peru(ian go(ernment* the total solid

&aste production reached an amount of 12,717 tons/day* &hich meant an anual global

production of aorund 4.6 million tons.

9o&e(er* if &e ta.e te solid &aste generation per inhabitant* &e can see that there is an

une6ual distribution regarding the different 0ones of the country* as it is reflected in the

net figure) The CGP ;Generacin Per Capitain spanish= is measured in .g@inhabitant@day)

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http://www.redrrss.pe/material/20140423145035.pdfhttp://www.redrrss.pe/material/20140423145035.pdf


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Plastic &aste production

This fe& data can help us dra&ing a broad picture of Peru,s solid &aste production* but &e

&ant to study one particular type of &aste4 plastics)

2e can ta.e out from the mentioned document the follo&ing conclusions) 1fter organic

matter ;&ith around 5!


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In this case* as &e can see in figure #* most of the plastic &aste is produced near the sea

and at the mountains)

2aste treatment

Currently* &aste treatment in Peru is mainly based on dumping sites and landfills) 1lmost

1,!!! tonsof solid &aste are disposed e"eryday) There is no need to mention that the

situation has to and can be impro(ed)

'egarding the recycling data* only 2.12 #of the total solid &aste is recycled* &hich means

ust $7 tons per year.

This general (ie& of Peru,s solid &aste production* focusing on plastics in particular* is the

starting point for our proect)

%nce &e targeted our location* &e need to define a llittle bit more &hich are the .ey points

of our technical idea* starting &ith the energetic source &e are going to use* that is*

geothermal energy)

%eothermic potential

Aet us define &hat the geothermic potential is)

Energy can come in many &ays* such us by the hand of fossil fuels* nuclear fuels or non

polluting media) Geothermal energy belongs to the third group* and it,s based on the idea

of using earth,s internal energy* the one produced by the earth,s origin and the radioacti(e

decay of the materials in the inner crust) 9o&e(er* the use of this rene&able energy is

tightly restricted to areas &ith high tectonic plate acti(ity) 1ny&ay* it has been stated that* if

properly eploited* geothermal energy &ould be more than enough to co(er humanity,s

energy needs)

9a(ing described &hat geothermal energy is* it,s logical to assume that the geothermic

potential is the capacity a certain area has to ta.e ad(antage or e(en to eploit the

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geothermal resources of said area) 1s mentioned before* geothermal energy depends

directly on the boundaries bet&een the tectonic plates) That,s one of the reasons &hy &e

ha(e chosen Per) 1s it can be seen in the follo&ing image* Per is an area located right

bet&een the +outh-1merican plate* &hich forms the main part of its continental territory

and the ?a0ca plate* located in the pacific ocean and sharing a relation of subduction)

1dded to the fact that Per has a great seismic acti(ity produced by the collision of said

plates* it is one of the countries &ith the biggest number of (olcanoes in +outh-1merica)

This is highly important &hen focusing our proect* as our main goal is to ta.e ad(antage

of that heat produce underground)

E(en though there are plenty of (olcanoes in

Per* ust a fe& of them are actually acti(e)

The most important ones are the follo&ing4

/isti* :binas* 9uaynaputina* Ticsani* +ara

+ara* +abancaya* Coropuna* 1mpato*

Tutupaca* Bucamana* Purupuruni and Casiri)

1s it can be seen in the follo&ing image* the

grand maority of those (olcanoes are near t&o

of the most important cities in Per4 1re6uipa

and /o6uegua)

These cities are some of the main ones &hich

hold the biggest geothermic potential* due to their proimity to (olcanoes and to &here the

plates collide)

In fact* Per* &ith the appropiate technology and in(estment* is said to be able to pro(ide

up to 3/2 of electricity per hour) In fact* a report carried out by apan,s agency of

international cooperation has demonstrated this potential) 9o&e(er* /asami ?a.aga&a*

professor at the /ining College of Colorado* says this report is still preliminar and that the

estimated potential could be e(en higher) The only reason &hy this isn,t being eploited is

because it is not profitable)

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The area surrounding the (olcanoes signifies a big and dangerous ha0ard to the

population nearby) In case of an eplosion* or e(en the release of gases could signify the

loss of human li(es) 1s in can be seen in the follo&ing t&o images* there,s an area

surrounding (olcanoes &here the damage and ris. of settling there is etremely high)

9o&e(er* if placed on the non ha0ardous surroundings* &e &ould be able to ta.e

ad(antage of the incredibly high temperatures near the cone of the (olcano and carry on

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Image provided by Per's institute of sismoogy!

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/isti (olcano :binas DolcanoImages pro(ided by Per,s institute of sismology

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our proect)

1dditionally* the /isti (olcano is 6uite near the city of 1re6uipa* signifying our station could

be placed in a neuralgic center of Per and perhaps impro(ing the economic gro&th of the

city)

1s stated before* this ta.es ad(antage of the radioacti(e decay and other sources* such as

the residual heat of the planetary accretion ;&ith &ould mean the gra(itational binding

energy=* the latent heat produced by the crystalli0ation of the inner core in the interphase

of the outer core and other sources)

It has been estimated that the geothermal gradient orbits around #5-3! C@Fm in the

earth,s lithosphere* but this (aries greatly and it doesn,t follo& a linear proportion* as in thenucleus it has been estimated that the temperature is about 5!!!->!!! C)

This geothermal gradient is highly important for us* as all of our proect &ill be focused in

the temperatures &e can obtain in this &ay)

&hoosing of P'( and recycling method

:p to this point* &e ha(e eplained the basics of geothermal energy* and its potential use

in some sort of industrial plant &ith high temperatures needs)

1ttending to the global plastics production* there is no doubt about PET,s rele(ance

among all of its competitors))

Polyethylene terephthalate ;PET=* is a saturated polyester used generally in the production

of plastic bottles) The &orld,s production is currently around 3# million tons per year* &hich

ma.es it the most used thermoplastic polymer in the &orld)

The recycling of PET has under&ent an enormous de(elopment during the last years) 2e

can distinguish t&o main type of recycling processes of PET4 mechanical and chemical)

The first one is bounded to modify the properties of the polymer &ith no significant

changes in its composition* but &e are going to focus on the second one)

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PET recycling industry is no&adays speciali0ed on e(erything related to bottles) It

represents almost 3! < of the total production of PET* so &e are tal.ing about an

important path to follo& in recycling of polymers)

There are se(eral processes of recycling PET bottles that can be in some &ay potentiallycapable of being transformed into massi(e industrial applications ;pyrolisis* gasification*

hydrogenation* etc=* but &e are interested in methanolysis.

/ethanolysis of polyethilene terephtalate

There are 6uite a fe& &ays to approach this process* but a general (ie& could tell us that it

consists in the depolymeri0ation of PET by adding ethylene glycol at particular (alues ofpressure and temperature)

1t the end of the process* &e &ill be obtaining organic ra& materials that can be easily

used later at an industrial le(el) This constitutes one of the main ad(antages of

methanolysis)

Aet,s eplain no& &hat are the .ey features of this process* so &e can relate it after &ith

the &hole proposal of the proect)

PET depolymeri0ation

irst of all* the PET depolymeri0ation is carried out &ith ethylene glycol* ;PET@EG ratio of

@>=) 1 catalyst* such as 0inc acetate* can be used in this part of the process) The

reaction could need mechanical agitation or mo(ing to ensure a high chemical efficiency*

and a nitrogen atmosphere)

The result of this depolymeri0ation is a monomer .no&n as bis ;#-hydroy ethylene=

Insaturated polyester synthesis

1fter the depolymeri0ation has ta.en place* the resulting monomer can be effecti(ely used

for an insaturated polymer resin production) y adding maleic anhydride to the monomer

and the ethylene glycol* and using some catalyst as calcium acetate* &e are ready to carry

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out the synthesis of the ne& organic product)

irst of all* constant agitation is needed for the same reason eplained before)

Temperature needs to be progressi(ely raised* from around H! C to !C* &ith a

temperature increment speed of around C@min)

1fter this process ta.es place* the obtained product is an insaturated polyester resin*

&hich can be used in a broad field of applications ;adhesi(es* reinforced plastics* electric

isolation* coating* etc)=

2e,ll try to appyy this principles of functioning of PET recycling in our mechanism)

)escription of the mechanism

Aet us no& define the structure &e ha(e thought about)

1lthough poorly dra&n* the idea is still clear) The &hite pipe &ould be the one containing

the molten polymer) It &ould the follo& the direction stated by the arro&s and it &ould be

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pumped by pressuri0ed bombs* schematically dra&n as rectangles) The reason &hy it has

a triangular form is because &e,(e thought about sa(ing the more energy &e can* so the

polymer can flo& do&n&ards in case it solidifies in the upper part and then pressure is not

needed in that path of the pipe)

'egarding &hat re(ol(es around the pipe it is another one* although &e,(e thought aboutt&o* containing &ater) 1ccording to the basic principles of functioning of a geothermal

station* &ater produces energy by turning into (apor due to the temperature of the crust*

thus ma.ing the turbine to spin and generating energy)

2e,(e thought about the possibility of ta.ing ad(antage of the heat the &ater already has

&hen going through the pipes and by contact &ith the polymer pipe* it &ould melt the

polymer at the same time &e obtain energy)

This energy &ould then be used to po&er the pressuri0ed bombs in case they,re needed*because another factor &e ha(e to deal &ith is the a(oidance of the condensation of &ater

in the upper part) This &ould be a really serious problem* because the production of

energy &ould be stopped)

2e,(e decided to face this problem according to the phase diagram of the &ater* &hich is

gi(en no&4

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2e,(e stated that &ater must compulsorily be in a (apor state* and thus &e8(e got to

ac6uire a balance bet&een pressure and temperature in the bro&n area of the plot* ta.ing

into account the temperature gradient and the pressure one underground) That8s &hy

&e8(e thought that the bombs may also be pro(en useful to obtain the pressure re6uired in

case the difference of temperature in the different parts of the pipe is sufficiently big to beta.en into account)

%eographical location of our plant

or this ne& treatment plant* &e need t&o things4

)= The possibility of an easy management of the input@output) This means being

nearby a great &aste production center ;input= and a distribution one ;output=*&here* once they are separed and treated* the recycled ra& materials can be sold*

echanged* deli(ered* etc)

#)= The disponibility of geothermal energy for the ne& processing route for recycling

plastic &aste* so the plant has to be in a 0one &ith (olcanic acti(ity)

%nce &e ha(e stated the t&o main needs* &e ha(e to discuss also other topics* such as

the transport of the imput@output* &hich should be the easiest* cheapest and less harmful

for the en(ironment)

irst of all &e ha(e to discuss the placement of our plant* using the information that &e

already .no& about Peru) 2e can organi0e it this &ay4

?atural distribution of the population and orography4 The biggest and most cro&ded

cities on Peru are on the seaside) The mountains and the rainforest don,t ha(e so

much population)

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'egarding population* &e already .no& that the mayority of the population li(es on

the coast* and it,s in the coast &here &e can find the biggest cities so far)

Aima4 it is the capital and the largest city of Peru) 2ith a population of almost !

million* Aima is the most populous metropolitan area of Peru* and the third

largest city in the 1mericas ;as defined by Jcity properJ=* Aima also has one of

the biggest ports on +outh 1merica* KThe Callao PortL)

1re6uipa4 Is the second largest city In Peru* &ith a population of more than

H!!)!!!)

Truillo4 Is the third largest city in Peru* &ith a population (ery similar to

1re6uipa* around H!!)!!)

2e can see no& that the biggest city by far is Aima* and this means that is the one &ith the

biggest &aste production of all the country)

%nce &e ha(e gathered this information* it,s easy to see that our plant has to be near

Aima* but the second thing &e ha(e to care about is the distance of potentially usable

geothermal energy) It seems logical that* as told before* there &ill be more sysmic and

(olcanic acti(ity near the mountains)The net topics to discuss are this ones and also the

transportation from the city to our plant)

1s &e ha(e seen the 0one of Peru &ith the biggest (olcanic acti(ity is near

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1re6uipa* on the southern part of Peru* not (ery far from the border &ith Chile and

oli(ia* and also (ery near the city of 1re6uipa* the second largest)

1s &e can see there is a lot of (olcanic acti(ity that can help us in our proyect* and

also &e can ta.e ad(antage of the proimity of 1re6uipa* but &e ha(e to deal &ith

the transport of the &aste from other big cities li.e Aima)

'egarding peru(ians roads and other communications* this could be a posible

limitation to the transport) ut* as it can be seen in the map belo&* there is actually

a road &hich communicates both Aima and 1re6uipa &ith some (olcanic 0ones)

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*ur concept of the +aste separation plant

This &on,t be the inno(ati(e part* &e &ill use a &aste separation plant to separate the

residues for accomplishing t&o goals4

:sing the PET &aste as an input for our second process of PET recycling)

+eparate the residues into the desired ones* li.e paper and other plastics that &e

can sell to recycling plants* and non-desired ones as the organic residues that &ill

go to the landfill)

+o &e aim to build a plant &ith t&o big steps of &or.ing4

) /anual separation4 that &ill be useful to separate the &aste that comes all together

in the same trash can) 2e &ill separate bul.y items ;appliances* furniture* etc)= andspecific contaminants ;e)g)* ha0ardous &aste= by manual remo(ing to further

processing)

#)

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Physical and Physico-Chemical processes &ithin the net steps4

+i0e reduction of the trash to reduce the si0e and (olume of the trash) or an

easy further processing)

:se of a Trommel separator to separate the smallest materials)

+uspension /agnet* for ta.ing out the ferrous metalic &aste and lea(e the other

&aste to further treatment)

The ferrous material &ill rise and go &ith the magnet* and the plastic and the

non ferrous &aste &ill stay do&n) %nce the e is separate &e &ill collect the

&aste and try to sell it to other recycling plants)

1nd for further processing &e &ill use automatic pic.ing systems* li.e the ones

of the mar. K+teinertL* ;for eample the K?I'-:ni+ort P that is used for

separating the used e(erage Containers* PE and also the PET mied and alsoseparate the PET mied to coloured to non-coulored using a KColor +orting

+ystem :nisort CL=)

+o &ith this techni6ue &e ha(e already separated the PET from the &aste* and

&e &ill be able tocollect this and use it for the geothermal recycling process)

1lso it,s useful the use of Eddy Current separators ;Electrostatic +eparation= so

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&e can separate the &aste into conducting* non-conducting and semi-

conducting materials

In this last stage &e &ill separate the paper from the other &aste that &ill go to a

landfill* so &e &ill use the &eight differences for separating the paper* using a

(ertical air classifier)

%nce the &aste is separated in different materials* &e can go on to the second process4

) %nce the PET is separated &e can go on to the recycling process using the

geothermal energy)

#) 2ith the rest of the separated &asted &e &ill try to sell the one that can be recycled

;li.e paper* other plastics* metals= and &ith the organic &aste &e &ill carry them to

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the municipal landfill that already eists in the country)

Ta.ing apart the PET ;including colored and non-colored= * the rest of the separated

materials are in perfect condition to sell them to other enterprises that are into the

recycling bussines)

ust to sho& some eamples* the easiest one to sell for further recycling processing are

metals* here are some prices for metals scrap or &aste)

ut there are many entrepises that are loo.ing for&ard to buy &aste ;plastics* metals*

paper and more= for further recycling processes) :sing another eample* in +pain there is

an enterpise call KEuresi M 2aste /anagementL that on its &ebsite &&&)euresi)comtry to

sell or@and buy se(eral types of plastic ;PET* PE* 1+* P//1@PDC=)

2&
http://www.euresi.com/http://www.euresi.com/


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&onclusions

%ur initial intention &as to stablish a general picture of a possible use of geothermal

energy for po&ering a simple PET recycling plant)

Geothermal energy has the ad(antage of representing a direct source of energy* that is*

there is no need of transformating its po&er into electric or mechanical energy)

ecause of this* &e thought of it as an important researching field &hich could be

de(eloped in those countries that ha(e an intense sysmic acti(ity)

1lthough &e ha(e been focused on the technical idea* &e &anted also to eplore theeconomical* social and logistical aspects of this plant design* installation and eploitation)

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geothermal approach to pet recycling

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