ene gies
A icle
P oblems Rela ed o Gasi ica ion o
Biomass—P ope ies o Solid Pollu an s in Raw Gas
Jan Najse 1, Pe Bu yan 2, Se gej Skoblia 2, Ja osla F an ik 1, Jan Kiela 1and Vacla Pee 1,*
1
ENET Cen e, VSB-Technical Uni e si y o Os a a, 17. lis opadu 15/2172, 70833 Os a a-Po uba, Czech Republic;
jan.najse @ sb.cz (J.N.); ja osla . an ik@ sb.cz (J.F.); jan.kiela @ sb.cz (J.K.)
2Depa men o Gaseous and Solid Fuels and Ai P o ec ion, UCT P ague, Technicka 5,
16628 P ague 6-Dej ice, Czech Republic; pe [email p o ec ed] (P.B.); se [email p o ec ed] (S.S.)
*Co espondence: acla [email p o ec ed]; Tel.: +42-0597-327-156
Recei ed: 31 Decembe 2018; Accep ed: 8 Ma ch 2019; Published: 13 Ma ch 2019


Abs ac :
Nowadays, he mochemical biomass con e sion appea s o be a e y p omising way o
p ocess hea and s eam gene a ion, o use in a cogene a ion uni engine, o o example in gas
u bines p oducing elec ical ene gy. The bigges p oblem ega ding using he syngas in in e nal
combus ion engines, a e pollu an s, which ha e qui e an inauspicious in luence on hei p ope
wo king. This a icle deals wi h he es ablishmen o he dis ibu ion size o solid pa icles cap u ed
by he ibe il e s in he syngas wi h a sui able cleaning design. Gas was p oduced in he ixed-bed
“Imbe ” ype gene a o . Fil e cake, which con ained pollu an s, was cap u ed on a il e and hen
analyzed. Based on single o al solid pa icles (TSP) componen s, we conclude ha his includes i s
pa ial elimina ion.
Keywo ds: gasi ica ion; biomass; o al solid pa icle
1. Gasi ica ion o Biomass
In ecen yea s, biomass, as a enewable sou ce o ene gy, has a ac ed ising a en ion a ound
he wo ld [1].
The he mochemical ans o ma ion o biomass (py olysis, gasi ica ion) seems o be one o
he mos p omising ou es owa ds he u iliza ion o enewable sou ces o ene gy o ob ain ene gy.
These enewable o ms o ene gy p esen many ecological bene i s. Wi h espec o he mochemical
con e sion echnologies, ixed-bed [
2
] o luidised bed [
3
] gasi ica ion a ac s he g ea es a en ion
because i o e s highe p ocess e iciency han combus ion and py olysis.
The p ocess o con e sion o solid ca bonaceous uel o lammable gas by pa ial oxida ion is
known as gasi ica ion. The esul an gas, which is some imes called p ocess gas, is much mo e e sa ile
in i s use han he o iginal solid biomass [
4
]. The g ea ad an ages a e ha he syn hesis gas can be
s o ed and anspo ed, and i s inal use can be independen o he p oduc ion p ocess [
5
]. Du ing inal
p ocessing he syn hesis gas can be combus ed o p oduce p ocess hea and s eam o used in gas
u bines o he p oduc ion o elec ici y.
In e ms o a gasi ica ion medium, he echnology can be di ided in o gasi ica ion by ai , oxygen,
wa e apo s, CO2, o o he a ious combina ions [6].
2. P oblems o Gasi ica ion Technologies and Thei Solu ions
Cu en ly, du ing he de elopmen o new echnologies o ans o ming he ene gy con en
o biomass as a enewable ene gy sou ce o i s mo e sophis ica ed o m, a en ion is ocused on
he de elopmen o new echnological equipmen o mo e e icien gasi ica ion, o he mochemical
con e sion. In his echnological segmen , he majo i y o esea ch wo k is aimed a he cleaning o aw
Ene gies 2019,12, 963; doi:10.3390/en12060963 www.mdpi.com/jou nal/ene gies
Ene gies 2019,12, 963 2 o 14
gene a o gas, because a and solid pollu an s (SP) p esen in he aw gas a e he main undesi able
componen s in he gas, limi ing i s use in combus ion mo o s o cogene a ion uni u bines [7].
The inc ease in p oduc ion e iciency se s e e g owing demands o gas cleaning [
8
]. The bene i s
o gasi ica ion also include he possible educ ion o emissions, emissions o compounds o Sulphu ,
chlo ine, and ni ogen, bu also pe sis en o ganic pollu an s (POP), e.g., polychlo ina ed benzodioxines
and benzodi u anes (PCDD, PCDF). Reduc ion o emissions is achie ed by emo ing hese compounds
and hei p ecu so s di ec ly om he p oduced gas p io o combus ion. The olume o gas is smalle
compa ed o he olume o p oduced lue gases; he concen a ion o pollu an s is highe , and mo e
e icien emo al in smalle echnological equipmen is possible. Pollu an s a e p esen in a educed
o m; hei agg essi eness owa ds equipmen is signi ican ly lowe .
2.1. Undesi able Subs ances
The choice o a sui able p ocedu e o cleaning depends on he echnology selec ed o i s
p ope ies and con en o undesi able componen s [
9
]. Undesi able componen s a e o med om
ino ganic componen s o uel o incomple e con e sion o ma e ial. They cause ab asion, co osion,
o ma ion o sedimen s, and deg ada ion eac ions, e.g., in ca alyze s, o hey ep esen ecological
loads [8].
The olume o con amina ing subs ances in he gas gene a ed du ing gasi ica ion is di ec ly
dependen on he con amina ion o solid uel. The olume o undesi able subs ances in biomass and
he con e sion p ocess can be signi ican , e.g., N, P, K, Si, Ca, Mg, S, Na, Cl [
6
]. The main po ion o
hea y and alkali me als (po assium 80%) end o s ay in he solid phase du ing uel con e sion [10].
The ollowing pollu an s a e o med du ing he gasi ica ion p ocess:
•
Solid pollu an s (SP) a e de ined as subs ances in he esul an gas o med by un eac ed biomass
ac ion and ash ma e (ino ganic subs ances). A ce ain p opo ion is also o med by soo , and
i s emo al is p oblema ic due o he p esence o a [
11
]. When he gas is cooled, he e is a isk o
mo e solid pa icles o ming. We sc ubbing, high- empe a u es ba ie il e s [
12
], cyclones, and
elec os a ic sepa a o s a e used o emo al pu poses [13].
•
Ta s can be de ined as o ganic subs ances which a e p oduced on he basis o he mal o pa ial
oxida ion o any o ganic ma e ial [
14
]. Gene ally i is p esumed ha a s a e la gely composed o
polycyclic a oma ic hyd oca bons (PAH). Ta subs ances can be classi ied as p ima y, seconda y, o
e ia y, acco ding o he ope a ing condi ions unde which hey o igina ed. P ima y a s, which
con ain oxygen in subs an ial olumes, a e o med by he decomposi ion o biomass building
blocks. Seconda y and e ia y a s a e o med by he des uc ion o p ima y a subs ances and
he ecombina ion o agmen s [
15
]. Du ing hese p ocesses, oxygen and pa icles o hyd ogen
a e emo ed [16].
•Compounds con aining ni ogen
•Alkaline compounds
•Sulphu
•Chlo ine
2.2. Gas U iliza ion
Gas can be combus ed in a bu ne , combus ion engine, o gas u bine. I gas is combus ed in a
bu ne , only hea is gene a ed. The dus is emo ed om gas in cyclones. Du ing combus ion in an
engine o u bine, he bene i is elec ici y and was e hea . I he gas is a uel o a combus ion u bine,
i mus be de-dus ed. Ta s do no need o be emo ed because he empe a u e in he u bine chambe
is way abo e he a dew poin . Ta emo al is equi ed when he gas is used in a combus ion engine.
The demands o gas quali y a e inc easing om gas mo o s o uel cells. Tables 1and 2show he
gene al equi emen s o gas quali y o a gas u bine and o comp ession igni ion and spa k igni ion
engines. Table 3shows he limi s o pollu an s o Mol en Ca bona e Fuel Cells (MCFC) ope a ion.
Ene gies 2019,12, 963 3 o 14
Table 1. Requi emen s o gas quali y o gas u bines [17].
Pa ame e Value
Minimum hea ing alue (MJ.mn−3)4–6
Minimum hyd ogen con en (% ol.) 10–20
Maximum supply empe a u e (◦C) 60–450
Maximum concen a ion o alkali (ppb) 20–1000
Ta a inle empe a u e In gaseous phase o none
Sulphu (ppm) <1
HCl (ppm) <0.5
Maximum con en o solid pa icles (ppm)
A e age >20 mm <0.1
10–20 mm <1
4–10 mm <10
Table 2. Requi emen s o gas quali y o comp ession igni ion and spa k igni ion engines [17].
Pa ame e Value
Maximum hyd ogen con en (% ol.) 7–10
Maximum ela i e humidi y (%) 80
Maximum supply empe a u e (◦C) 40
Maximum ammonia con en (mg/10 kWh) 55
Maximum a con en (mg·mn−3)<100
Maximum halogens con en (mg/10 kWh) <100
Maximum con en o sul u ecalcula ed o H2S (ppm) 2000
Maximum con en o solid pa icles (mg·mn−3)5–50
Table 3. Pollu an limi s o Mol en Ca bona e Fuel Cells (MCFC) ype uel cells [18].
Pa ame e Value
Maximum sul u con en (ppm) <0.1
Maximum ammonia con en (% ol.) <0.1
Maximum hyd ogen cyanide con en (ppm) <0.1
Maximum chlo ides con en (ppm) <0.1
Maximum luo ide con en (ppm) <0.1
Maximum a con en (ppm) <2000
Maximum pa icle size (µm) <0.01
Maximum lead con en (ppm) <1
2.3. SP Remo al
To emo e mechanical impu i ies and a d ople s o igina ing om condensa ion, sepa a o s a e
used, wi h g a i a ional se lemen , cen i ugal o ces, il a ion, sc ubbing, and elec os a ic apping
in a high- ension elec ic ield. Acco ding o he p inciple o hei ac ion, hey a e di ided in o:
•Ine ial (momen um),
•G a i a ional (ho izon al, e ical and sphe ical),
•Cen i ugal (cyclone),
•Fil a ion, combined.
The mu ual compa ison o he espec i e ypes o equipmen wi h he size o he pa icles o
apped ae osols is shown in Figu e 1. When choosing he ype o sepa a o , i is necessa y o ake in o
accoun ha ce ain ypes o pa icles agglome a e in la ge agg ega es, which acili a e he cleaning
o gases.
Ene gies 2019,12, 963 4 o 14
Ene gies2019,12,xFORPEERREVIEW4o 13

Figu e1.Compa isono  ypeso sepa a o s o  appingae osolpa icles[19].
Today, he emo alo  a  omgene a o gas,due o hephysiochemicalp ope ieso o ganic
subs anceswhich o mi ,iso enpe o medin echnologicalp ac icebyapplyingmodi ied
physiochemicalp ocessesde elopedin hepas  o gasi ica ionandca boniza iono coal.O ganic
subs ances,whicha esimila inna u e o hecompounds o ming a s,a eusedas hewashingliquid
in hesep ocesses.Thead an ageo applyingo ganicsubs ancesincompa ison owa e washingis
he ac  ha a  empe a u eso a ound50°C,amuchlowe  a con en in hegascanbeachie ed
downs eamo  hewashe wi hou condensa iono wa e  apo  om hegasandp oblema icwa e 
solu ionso emulsions.
Howe e ,in hesecases,pu suan  o he uleso  he modynamicequilib ium, heinc easing
con en o  a in hewashingliquidinc eases he esidualconcen a iono  a in hegas.Thismeans
ha in hecaseo concen a iono  a in heabso p ionmedium, heconcen a iono  esidual a 
componen sin hegass a s oinc ease.Du inggasi ica iono biomass, hesa u a edabso p ion
solu ioninsmallequipmen  ypicallydoesno  egene a ebu iscombus edo gasi ied.Thisleads o
inc easedope a ingcos s.Se e alp ac icalapplica ionsunde  a ious adeabb e ia ionsa e
known.Thebes knownandlonges usedapplica ioniscleaningo gas oman8MW  luid
gasi ica iongene a o wi haci cula ionbedo cogene a ionuni sinGüssing(Aus ia),whe e he
con en o  a in hegasis educed om1500mg∙m−3 o10–40mg∙m−3(a a empe a u eunde 50°C).
Suchcleanedgasiscombus edin hecogene a ionuni enginewi hanou pu o 2MWe,and he
usedbio‐dieseliscombus edin hecombus ionsec iono  hegene a o [20].
Reduc iono  he a con en ingasalsoenablesop imiza iono  heope a ingpa ame e so 
gene a o swi ha luidbedwi hca aly icallyac i ema e ialope a inga  empe a u eso e 900°C.
Thegene a iono gaswi hlow a con en canalsobeachie eddu ingope a iono aso‐called
dual‐s agegene a o ,u ilizing hep incipleo pa ialoxida iono py olysisp oduc s ep esen edby
ahighcon en o  a componen s eleasedin hepy olysissec iono  hegene a o [21].Inaddi ion,
aconcu en gene a o suchas he“Imbe ” ype,p oducesgaswi hlow a con en ,p o ided ha 
echnologicalcondi ionsmainly espec ing hebiomassp ope iesa ecompliedwi h.Thisgene a o 
Figu e 1. Compa ison o ypes o sepa a o s o apping ae osol pa icles [19].
Today, he emo al o a om gene a o gas, due o he physiochemical p ope ies o o ganic
subs ances which o m i , is o en pe o med in echnological p ac ice by applying modi ied
physiochemical p ocesses de eloped in he pas o gasi ica ion and ca boniza ion o coal. O ganic
subs ances, which a e simila in na u e o he compounds o ming a s, a e used as he washing liquid
in hese p ocesses. The ad an age o applying o ganic subs ances in compa ison o wa e washing
is he ac ha a empe a u es o a ound 50
◦
C, a much lowe a con en in he gas can be achie ed
downs eam o he washe wi hou condensa ion o wa e apo om he gas and p oblema ic wa e
solu ions o emulsions.
Howe e , in hese cases, pu suan o he ules o he modynamic equilib ium, he inc easing
con en o a in he washing liquid inc eases he esidual concen a ion o a in he gas. This means
ha in he case o concen a ion o a in he abso p ion medium, he concen a ion o esidual a
componen s in he gas s a s o inc ease. Du ing gasi ica ion o biomass, he sa u a ed abso p ion
solu ion in small equipmen ypically does no egene a e bu is combus ed o gasi ied. This leads o
inc eased ope a ing cos s. Se e al p ac ical applica ions unde a ious ade abb e ia ions a e known.
The bes known and longes used applica ion is cleaning o gas om an 8 MW luid gasi ica ion
gene a o wi h a ci cula ion bed o cogene a ion uni s in Güssing (Aus ia), whe e he con en o a in
he gas is educed om 1500 mg
·
m
−3
o 10–40 mg
·
m
−3
(a a empe a u e unde 50
◦
C). Such cleaned
gas is combus ed in he cogene a ion uni engine wi h an ou pu o 2 MWe, and he used bio-diesel is
combus ed in he combus ion sec ion o he gene a o [20].
Reduc ion o he a con en in gas also enables op imiza ion o he ope a ing pa ame e s o
gene a o s wi h a luid bed wi h ca aly ically ac i e ma e ial ope a ing a empe a u es o e 900 ◦C.
The gene a ion o gas wi h low a con en can also be achie ed du ing ope a ion o a so-called
dual-s age gene a o , u ilizing he p inciple o pa ial oxida ion o py olysis p oduc s ep esen ed by
a high con en o a componen s eleased in he py olysis sec ion o he gene a o [
21
]. In addi ion,
a concu en gene a o such as he “Imbe ” ype, p oduces gas wi h low a con en , p o ided
ha echnological condi ions mainly espec ing he biomass p ope ies a e complied wi h. This
Ene gies 2019,12, 963 5 o 14
gene a o in i s a ious modi ica ions, is he mos common gene a o in small cogene a ion uni s in
he Czech Republic.
An o en-unde es ima ed ac o du ing he exploi a ion o simila uni s is he ing ess o ine SP in o
he cylinde space o he combus ion engine om whe e hei esidues a e combus ion a e mainly
pulled in o he oil, he eby comp omising i s lub ica ing p ope ies, alkalini y, and sho ening i s
eplacemen in e al. Quan i y o SP which exceeds limi s se by engine manu ac u e s also inc eases
wea o he in ake duc ing and cylinde s and, in he case o he use o a u bocha ge , i also causes i s
accele a ed wea .
The synch onous impac o he abo e-men ioned ac o s is one o he easons o insu icien
economic e iciency o gasi ica ion uni s ope a ed oday in he Czech Republic. An imp o emen in
he si ua ion can be achie ed mainly by using mo e e icien SP emo al, p e e ably using ba ie
il e s ope a ed abo e he dew poin o a s and wa e apo s in he gas. In cases whe e he emo al
o a and SP is pe o med simul aneously, he e is a high isk o o ma ion o a s icky il a ion cake,
causing signi ican p oblems in i s subsequen emo al om he il e su ace. This p ocess has a
p og essi e cha ac e and he deg ee o il e su ace deg ada ion g adually inc eases du ing ope a ion.
A wo se condi ion can only be he pene a ion o condensed a in o he ac ual il a ion ma e ial.
The desc ibed p oblem occu s qui e o en du ing s a ing-up o he gasi ica ion echnology. Raw ho
gas en e s he cold space wi h he il a ion elemen s, which con ains amongs o he s, much mo e
a a engine s a -up han du ing he s abilized ope a ion. Upon con ac wi h he cold il e he gas
immedia ely cools, a and wa e apo condense, pene a e he il e s uc u e and pa icles bond o
he il e . A e a ce ain ope a ion pe iod he il e hea s up o he necessa y empe a u e, bu due o
he polycondensa ion and polyme iza ion eac ions o eac i e a componen s he il e is pe manen ly
clogged, inc easing i s p essu e loss and p e en ing i s u he use, o en leading o he ailu e o he
cleaning sys em, which hen equi es eplacemen o he il a ion elemen s. A simila “ esul ” can
also be achie ed qui e easily by using cold p essu e media o egene a ion o he il e du ing e e se
impulse pu ging.
The co esponding design o il a ion ma e ials and il e designs equi e knowledge o he
amoun , composi ion, and dis ibu ion o SP pa icles, which mus be emo ed om he gene a ed gas
in ce ain cases, o he limi o he con en o o ganic subs ances adso bed by he apped solid pa icles
mus be de e mined. Well known solu ions o SP and a s emo al om big acili ies including ho
il e s o emo ing SP, ca aly ic decomposi ion o a s, o o he sophis ica ed de ices a e no sui able
o small ene gy uni s because o hei high in es men cos s.
A ce ain p oblem wi h he ope a ion o gene a o s gasi ying wood is he o ma ion o inc us s in
he gene a o ’s i e g a e, which limi s he discha ge o solid esidues om he gasi ying gene a o , as
well as he ac ual ope a ion o he gasi ica ion p ocess.
3. Expe imen al Sec ion
3.1. Gasi ica ion Technology
The subjec o he s udy was he de e mina ion o dis ibu ion o he size o solid pa icles apped
by he slee e il e om gas p oduced by a gasi ica ion gene a o wi h a solid bed, ype “Imbe ”,
necessa y o he objec i e design o he il a ion ma e ial o he de eloped il a ion slee e equipmen
o emo al o SP, hei composi ion, quan i y o adso bed o ganic subs ances, and composi ions o
inc us om he gene a o ´s i e g a e.
The ope a ed gene a o was i ed wi h gasi ica ion ai p ehea ing by was e hea om he eac o
in he ins alled hea exchange . This enabled achie emen o a gasi ica ion ai empe a u e o 200 o
240
◦
C and gasi ica ion empe a u e o 780–830
◦
C. The a e age consump ion o woody biomass was
82 kg/h, he amoun o ai low was no measu ed. The whole expe imen las ed o 16 h.
The o ake o gas om his gene a o was pe o med om he op sec ion om he ube leading
p oduced gas om he gene a o , o he gas cleaning sys em. A closu e al e is loca ed in he op

Ene gies 2019,12, 963 6 o 14
sec ion o he gene a o o i s au oma ic illing using a high-li con aine . Gas ising om he gene a o
h ough he ou le channels (piping), wi h a empe a u e o app oxima ely 250
◦
C, was ou ed o a
collec o connec ed o he gas pipe, which lead o he ho mul i-cyclone and hen o he echnological
line whe e he o he equipmen was loca ed, including he moni o ed slee e il e equipped wi h 15
ex ile slee es (Figu e 2) wi h a diame e o 20 cm and a leng h o 1.2 m. The o al amoun o apped SP
du ing he whole expe imen was 10,282.1 g, which co esponds ha 0.78 w .% o uel was con e ed
in o SP.
Ene gies2019,12,xFORPEERREVIEW6o 13
ou ed oacollec o connec ed o hegaspipe,whichlead o heho mul i‐cycloneand hen o he
echnologicallinewhe e heo he equipmen wasloca ed,including hemoni o edslee e il e 
equippedwi h15 ex ileslee es(Figu e2)wi hadiame e o 20cmandaleng ho 1.2m.The o al
amoun o  appedSPdu ing hewholeexpe imen was10,282.1g,whichco esponds ha 0.78w .%
o  uelwascon e edin oSP.

Figu e2.Slee e il e  o  appingsolidpa icles(SP).
Incompliancewi h heobjec i eso  his ask,one ex ileslee e,whichwas es ed o  he
cleaningo  hegene a o gas o abou onemon h,was aken o de ailedanalysis om he es ed
d y il e (Figu e3).Thesolidpollu an swe eca e ully emo edmechanically omi sou e su ace.

Figu e3.F agmen o sampleo SP appedby he il e .
3.2.Fuel
The awma e ialp ocessedin hegene a o we econi e ouscu ings—maximumleng h10 o
15cm,maximumwid h5cm,andamaximum hicknesso 2cm.Thei  ypicalphysiochemical
p ope iesa eshowninTable4.Thep opo iono  inepa iclesandpa icleswi hba kin hegasi ied
ma e ialwasnegligible.This uelwasusedlong‐ e min hisuni .I wasa ailable,a o dable,and
hadgoodquali yandp ope ies o gasi ica ion.This ypeo ma e ialhadamediumagglome a ion‐
slaggingp opensi y[22].
Figu e 2. Slee e il e o apping solid pa icles (SP).
In compliance wi h he objec i es o his ask, one ex ile slee e, which was es ed o he cleaning
o he gene a o gas o abou one mon h, was aken o de ailed analysis om he es ed d y il e
(Figu e 3). The solid pollu an s we e ca e ully emo ed mechanically om i s ou e su ace.
Ene gies2019,12,xFORPEERREVIEW6o 13
ou ed oacollec o connec ed o hegaspipe,whichlead o heho mul i‐cycloneand hen o he
echnologicallinewhe e heo he equipmen wasloca ed,including hemoni o edslee e il e 
equippedwi h15 ex ileslee es(Figu e2)wi hadiame e o 20cmandaleng ho 1.2m.The o al
amoun o  appedSPdu ing hewholeexpe imen was10,282.1g,whichco esponds ha 0.78w .%
o  uelwascon e edin oSP.

Figu e2.Slee e il e  o  appingsolidpa icles(SP).
Incompliancewi h heobjec i eso  his ask,one ex ileslee e,whichwas es ed o  he
cleaningo  hegene a o gas o abou onemon h,was aken o de ailedanalysis om he es ed
d y il e (Figu e3).Thesolidpollu an swe eca e ully emo edmechanically omi sou e su ace.

Figu e3.F agmen o sampleo SP appedby he il e .
3.2.Fuel
The awma e ialp ocessedin hegene a o we econi e ouscu ings—maximumleng h10 o
15cm,maximumwid h5cm,andamaximum hicknesso 2cm.Thei  ypicalphysiochemical
p ope iesa eshowninTable4.Thep opo iono  inepa iclesandpa icleswi hba kin hegasi ied
ma e ialwasnegligible.This uelwasusedlong‐ e min hisuni .I wasa ailable,a o dable,and
hadgoodquali yandp ope ies o gasi ica ion.This ypeo ma e ialhadamediumagglome a ion‐
slaggingp opensi y[22].
Figu e 3. F agmen o sample o SP apped by he il e .
3.2. Fuel
The aw ma e ial p ocessed in he gene a o we e coni e ous cu ings—maximum leng h 10
o 15 cm, maximum wid h 5 cm, and a maximum hickness o 2 cm. Thei ypical physiochemical
Ene gies 2019,12, 963 7 o 14
p ope ies a e shown in Table 4. The p opo ion o ine pa icles and pa icles wi h ba k in he
gasi ied ma e ial was negligible. This uel was used long- e m in his uni . I was a ailable,
a o dable, and had good quali y and p ope ies o gasi ica ion. This ype o ma e ial had a medium
agglome a ion-slagging p opensi y [22].
Table 4. P ope ies o used uel.
Pa ame e Value
Mois u e W (w .%) 16.73
Vola ile combus ibles V d(w .%) 82.99
Fixed ca bon F d(w .%) 16.71
Ash A d(w .%) 0.30
C (w .%) 49.86
H (w .%) 6.14
O (w .%) 43.38
N (w .%) 0.31
S (w .%) 0.01
HHV, we (MJ·kg−1)17.59
HHV, d y (MJ·kg−1)20.52
alues o o iginal wood sample; dd y sample wi hou mois u e.
3.3. Analy ical Me hods
Pa ame e s o he uel om Table 4(mois u e, ola ile, and ixed ca bon and ash) we e measu ed
by he mog a ime ic analyze Ne zsch STA 449 F1 Jupi e . The hea ing a e was 10
◦
C/min in a
ni ogen a mosphe e up o 900
◦
C. Fo he amoun o ash, he e was a change in ni ogen by oxygen
and hea ing con inued up o 1200
◦
C. Ul ima i e analysis o uel (amoun o C, H, O, N and S) was
measu ed by analyze LECO CHN 628 wi h added module 628 S. Combus ion hea was measu ed by
he calo ime e LECO AC600.
The mog a ime ic analysis (TG) was measu ed by he analyze Ne zsch STA 449 F1 Jupi e .
The hea ing a e was 10
◦
C/min in ni ogen a mosphe e. The di e en ial he mal analysis DTA was
measu ed simul aneously, which measu es he empe a u e di e ence be ween he s anda d sample
(aluminium oxide) and he sample du ing hea ing.
Composi ion o he il a ion cake ino ganic ac ion and inc us was measu ed wi h appa a us
ARL 9400 XP+ equipped wi h a Rh lamp wi h a head Be-oxides window.
The dis ibu ion o he apped pa icle size was pe o med by a F i sch Pa icle Size Analyse e
22 appa a us, whe e he ligh sou ce is an He-Ne-lase wi h a wa eleng h o 633 nm and maximum
measu ing ange o 0.1–1250
µ
m. To ensu e he homogenei y o he measu ed sample and eliable
s a is ics in he illumina ed olume, he suspension was pe manen ly mixed in an ex e nal mixing
de ice du ing measu emen using ul asound, which p o ided o he sepa a ion o he agglome a e.
The measu ing o o ganic subs ances composi ion apped by he il a ion cake was necessa y
o sol e hese subs ances in he sol en . Mechanically sepa a ed cake om he su ace o he ou e
il e laye was inse ed in o he Soxhle ex ac o and washed o ou hou s by ace one. The ob ained
solu ion was injec ed in o he gas ch oma og aph Hewle Packa d HP 6890 wi h a mass de ec o
Hewle Packa d MSD 5973 (GC-MS).
4. Resul s
4.1. Analysis o he Composi ion o he Fil a ion Cake
The solid pollu an s we e ca e ully emo ed mechanically om i s ou e su ace. The sample o
SP was es ed by he mog a ime ic analysis—see Figu e 4—un il 100
◦
C 1.5% by w . was eleased
in o he s eam o ca ie gas, un il 200
◦
C abou 2.5% by w ., un il 300
◦
C abou 7.5% by w ., and un il
400
◦
C abou 8% by w . The simul aneously pe o med DTA analysis ound ha he e is only one
Ene gies 2019,12, 963 8 o 14
signi ican endo he mal e ec , de ec ed a app oxima ely 725
◦
C. This e ec is p obably he mel ing o
he ino ganic ac ion o he il a ion cake.
Ene gies2019,12,xFORPEERREVIEW8o 13

Figu e4.The mog a ime icanalysis(TG)/DTAanalysiso  il a ioncake.
Thequan i yo ashin heSPsamplede e minedbyi scombus iona 850°Cwas37.28%byw .
Thequan i yo ca bondioxidein hesamplede e minedusingHClco esponding o hede ec ed
ca bona eswas2.7%byw .
4.2.Composi iono Ino ganicF ac ionandSPSizeo  heFil a ionCake
The esul so  hecomposi iono  he il a ioncakeino ganic ac ionwe epe o medusing
luo escen X‐ ayanalysisanda esumma izedinTable5.
Table5.Composi iono  he il a ioncakeino ganic ac ion.
Subs anceCon en (w .%)Subs anceCon en (w .%)
Al2O316.73NiO0.07
BaO0.83P2O55.54
CaO16.71SO315.70
CdO0.30SiO212.93
Cl0.49S O0.14
C 2O36.14TiO20.08
CuO9.85Fe2O32.68
K2O0.31PbO0.06
MgO30.01ZnO1.47
MnO7.59Na2O2.37
Measu emen o  hedis ibu iono  appedpa iclesizewaspe o med o samples akenin he
middleo  ou slee esusing helase  echniqueAnalyse e.The esul sa eshowninTable6.Pa icle
sizeswe ein he angeo 10μm o3mm.
Table6.Cumula i epa iclesizedis ibu iono SP appedby il a ioncake.
%Slee e1(g)Slee e2(g)Slee e3(g)Slee e4(g)
10.9350.6650.6920.676
21.3660.9430.9760.963
52.6281.6241.6701.654
Figu e 4. The mog a ime ic analysis (TG)/DTA analysis o il a ion cake.
The quan i y o ash in he SP sample de e mined by i s combus ion a 850
◦
C was 37.28% by w .
The quan i y o ca bon dioxide in he sample de e mined using HCl co esponding o he de ec ed
ca bona es was 2.7% by w .
4.2. Composi ion o Ino ganic F ac ion and SP Size o he Fil a ion Cake
The esul s o he composi ion o he il a ion cake ino ganic ac ion we e pe o med using
luo escen X- ay analysis and a e summa ized in Table 5.
Table 5. Composi ion o he il a ion cake ino ganic ac ion.
Subs ance Con en (w .%) Subs ance Con en (w .%)
Al2O316.73 NiO 0.07
BaO 0.83 P2O55.54
CaO 16.71 SO315.70
CdO 0.30 SiO212.93
Cl 0.49 S O 0.14
C 2O36.14 TiO20.08
CuO 9.85 Fe2O32.68
K2O 0.31 PbO 0.06
MgO30.01 ZnO 1.47
MnO 7.59 Na2O 2.37
Measu emen o he dis ibu ion o apped pa icle size was pe o med o samples aken in he
middle o ou slee es using he lase echnique Analyse e. The esul s a e shown in Table 6. Pa icle
sizes we e in he ange o 10 µm o 3 mm.
Ene gies 2019,12, 963 9 o 14
Table 6. Cumula i e pa icle size dis ibu ion o SP apped by il a ion cake.
% Slee e 1 (g) Slee e 2 (g) Slee e 3 (g) Slee e 4 (g)
1 0.935 0.665 0.692 0.676
2 1.366 0.943 0.976 0.963
5 2.628 1.624 1.670 1.654
10 4.846 2.606 2.795 2.659
15 7.043 3.574 3.921 3.664
20 9.234 4.572 5.000 4.703
25 11.497 5.585 6.704 5.762
30 13.939 6.622 7.110 6.811
35 16.598 7.707 8.159 7.872
40 19.526 8.804 9.252 8.925
45 22.631 9.977 10.389 10.017
50 25.934 11.252 11.628 11.168
55 29.517 12.646 12.972 12.381
60 33.293 14.244 14.481 13.745
65 37.052 16.121 16.228 15.3
70 41.191 18.487 18.325 17.204
75 45.754 21.618 21.000 19.776
80 50.654 25.909 24.461 21.029
85 56.602 31.498 29.001 35.043
90 63.754 37.17 35.792 47.127
95 74.544 46.917 46.012 58.692
98 85.998 55.385 56.700 69.138
99 93.76 60.362 63.296 75.364
100 183.788 102.15 106.200 112.657
4.3. Analysis o O ganic Subs ances T apped by Fil a ion Cake
The nex pa o he esea ch wo k was ela ed o he iden i ica ion and quan i ica ion o he
componen s apped in he il a ion cake by he slee es (Table 7).
Table 7. Composi ion o o ganic subs ances cap u ed on he il a ion slee e.
Iden i ied Subs ance Con en (µg/g)
Benzene 30.4
Toluene 35.9
m + p + o-xylene + e hylbenzene 44.3
S y ene 0
C3-benzene o al (sa . + unsa .) 0
O he s 178.7
BTX o al 189.3
Oxygen con aining subs ances o al 180.1
Phenol 36.9
Me hylphenols 15.1
Dibenzo u anes * 128.2
Ni ogen con aining subs ances 0.0
Indene+indan 2.5
Naph halene 63.6
Me hylnaph halenes 20.0
Alkylnaph halenes (alkyl >= C2) 11.8
Biphenyl 15.5
Acenaph hylene 129.7
Acenaph hene 6.6
Fluo ene 42.9
PAH; m/z = 165–166 11.6
Phenan h ene 1470.0
An h acene 314.7