PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is to be performed.FIELD OF THE INVENTION
The present invention effectively utilizes themlal plasma to fix the essential nitrogen
components in water medium for the production of liquid fertilizer and green ammonia for
‘ ‘agriculture and sustainable energy applications, respectively. More specifically, it relates to
an apparatus and methods‘for the fixation of nitrogen compounjds. The present invention
utilizes air/nitrogen as nitrogen source and water as hydrogen source to fix nitrogen
components in liquid medium through submerged thermal arc plasma discharge.
BACKGROUND OF INVENTION
Nitrogen is actively present in the open atmosphere of about 78%, but crops need
4
nitrogen in the form of ions like ammonia (NHX) or nitrogen oxides (NOX’)such as nitrate
and nitrite. The increasing human population and energy demand forced to explore new green
and sustainable technologies for nitrogen fixation. Nitrogen triple bond (N E N) is one ofthe
I
strangest chemical bonds, and sufficient energy has to be applied to break nitrogen molecules
for artificial >nitrogen fixationNitrogen bond disassociation, ’vibrational excitation and
ionization energies are approximately 9.1 eV (8.7 x 105 J/mol), 1.5—4 eV (1.4 x 105— 3.8 x
IOSJ/mol) and 14.53 eV (1.39 x 10° J/mol) respectively.
Currently, the Haber—Bosch (HB) process is used to‘ produce 'ammonia to meet the
global demands. In this process, nitrogen (N2) from air and hydrogen (H2) from methane
(CH4) combine to fon'n ammonia with the support of catalysts under high temperature and
high-pressure conditions. HB process rgquires 3-5% ofthe natural gas produced in the world,
~.which_results in emission of more than 300 million metric’tons of C02 per annum,
Significantly contributing‘to global warming. In consideration to preserve the natural resource
and protect the environment, new technology has been introduced to reduce natural gas usage
in fertilizer production. Researchers are mainly focused on large—scale synthesis of ammonia
‘by reduction pathways such as photochemical and electrochemical methods and these
methods also have high energy consumption and deprived selectivity. Photochemical
reductiqn reaction has poor adsorption and oxidation of N2 on the catalyst surface.
Electrochemical reduction reaction requires more energy fél‘ stable N2 to absorb onto the
metal catalyst surface.
Recéntly, plasma technology has been shown more attractive, promising, and an
emerging tool for nitrogen fixation under atméspheric pressure conditions Plasma is the
fourth state of matter, it is defined as ionized gas of charged ions, electrons, atoms, and molecules which exhibits collective behavior. In plasma, the applied electric field produce
free electrons and ions, which activates the gas molecules by electron impact excitation,
ionization, and dissociation reactiofis. Depending on thermodynamical equilibrium
conditions, plasma is classified‘into thermal and non-themal plasma. By using plasma,
nitrogen fixation was first carried out by the process callgd the Birkeland-Eyde process,
where air fiasses through an electric arc to form nitric aqid; but the limitation ofthis process is
the high enefgy requirement for activation. Non-thermal plasma, like dielectric barrier
discharge (DBD), glow discharge (GD), spark discharge (SD), and gliding arc discharge
(GD), are the differént methods used so far for nitrogen fixation. Yuan et al, produced a
higher amount of nitrate and nitrite from the nitrogen and oxygén species using non-[henna]
plasma discharge. A simple handmade reactor was>designed by Punith et al, for the
production of nitrite (16.22 mg/l). Nitrate and nitrite fertilizers were produced from air and
water by the continuous flow of liquid-phase plasma discharge as reported by Sarah et a1 and
the maximum production ofNOx from their reactor was 136.2 mg/l.
Elisa vervloessem et al, used a différent ratio of Nz/Ozmixture for the production of
'NOx and ammonia using gliding arc plasma'atatmospheric pressure. Compared to the other
mqthods, this method shows an 8.2% higher NOxconcentration as’ well as reduced energy
cost. Pattyn et al, elucidated that increasg inthe Oz ratioin the N2/02 gas mixture decreased
- the NOx} concentration in the DC microplasma discharge process.A liquid film-dielectric
‘
‘bémer discharge plasma reactor was developedby Zhou for nitrogen fixation and nitrogen
>plasma directly interacts with watér'at atmosbhgric pressure find temperature to form nitrate
idns and ammonium 'ions,‘ without Usihg catalyst. and
I
hydrogen.~ This method has the
advantage of high energy Efficiency-and does not emit greenhouse gases'. A large zgmount of
ammo-nidwas synthesized by using a DBD reactor with and without the support ofa catalyst.N2 gas along with water vapor (H20) was passed through the electricalzgas discharge space
and a titanium catalys't was placed in tfie discharge region to, enhance the reaction raie as well
55 production yield.
Hence the drawbacks ofnon-thermal plasma for nitrogen fixatjon are low production
rate, low conversion and energy efficiency, and' long ti'eatment time: Méanwhile, th'ennal
plasma hashigh energy efficiency, no emission of greenhouse gases and waste products,and a
high production rate are the advantages‘From the above statement, it is necessary to inventan
effective method for proper utilization of thermal plasma to produce nitrogen components in
a liquid mediumAn attempt has been made to develop a submerged thermal plasma reactor for the fixation of nitrogen components in a liquid medium with a higher production rate and
energy efficiency. f.
OBJECTIVE OF THE INVENTION:
The main objective of the present invention is to develop submerged thermal plasma
apparatus for the fixation of nitrogen components in.water by using air/nitrogen and water at
atmospheric pressure.
Another objective ofthe present invention is to produce nitrogen-based liquid fertilizer (Nbg' '
and NH4+).for agriculture applicatibns without nitrite (N02) and other active radicalhydrogen
peroxide (H202).
The other objective of the invention is to produce green ammoniathrough thennal plasma
route at, atmospheric pressure using nitrogen from ai} and hydrogen from water as a
feedstock.
Yet another objective of the present invention ‘is td'enhan‘celthe energy efficiency and
production rate of nitrogen based- liquid fenilizcr by optimizing the processing parameters
and reactor design.
The other objective of the invention 'is to reduée the usége of chemical fenilizers and
emission ofthe greenhouse gases
Further objective of the present invention is to utilize the submerged thennal érc jaléIsma
processing for effecti've conversion of 'contamiriated water waste into liquid fenilizer for
agriculture and chemical industry. ,
'
SUMMARY:
Since toxic nitrite was not fonned in the present invention, froman agriculture point of
-
view, NOz' free liquid fertilizer plays a major role in inducing or accelerating plant growth as
well as yield. In this approach, N03' and NH4+ were mainly fixed as a nitrogen component in
the liquid fertilizers and they enhance crop production rate' without destroying the soil
microbes. In this present invention, the plasma-treated water dges not Show antimicrobial
activity due to the absence of active radicals like H202 and N02'.
The present invention of the thermal arc plasma nitrogen fixation process by using
air/nitrogen and water in submerged conditions was conducted under atmospheric pressure
conditions. Arc discharge inside the water medium by a low—powerplasma torch produces
free electrons, 'excited nitrogen molecules along with exited nitrogen atoms and ions. The
produced active species are controlled by optimizing the operating parameters such as
discharge power, gas flow rate, gas mixing ratio, treatment time, nozzle dimensions, water
circulation, etc.In this process, reactive species like Hydroxyl radical (OH') and OZone (03')
were formed during the air/nitrogen plasma integaction with the water mélecules,and theée
reactive species are supp‘oiting the formation ofN03' and NI—L;+ in the liquid medium.
In these embodimenté, the excited nitrogen species efficiently oxidizedto fonn nitrate
ahd undergo reduction to form ammonium in a submerged thermal arc plasma apparatus. In
submerged thennal plasma reaction, maximum production rate, energy efficiency and
sfieciflc energy consumption of produced NO3"were 25.7 g/hr, 4.5 g/kWhr and 0.79 GJ/kg,
respectively Similarly, the production rate, energy efficiency and specific energy
consumpfion of produced NH;r were 17.7 g/hr, 3.9 g/kWhr and 0.9 GJ/kg respectively.
As confixmed in the present invention, it enables the method for reducing chemical
feftilizer usage And emissioh of greenhouse gases andopens a new way for accelerating plant
growth rate and crop yield witho'ut killing any soil-bound micro-organisms.
BRIEF‘DESCRIPTION OF THE DRAWINGS
Figure.1.Defiicts the‘séhematic view of a submerged thennal arc plasma fixation of nitrogen
components in the water medium apparatus of the BRIEF‘DESCRIPTION OF THE DRAWINGS
Figure.1.Defiicts the‘séhematic view of a submerged thennal arc plasma fixation of nitrogen
components in the water medium apparatus of the présent invention:
-Figurc.2. shows the cross-sectional view of DC low power thermal plasma torch.
Figure.3. shows the optical emission spectrum 6f-Air/Ar plasmajet at a different flow rate in .
the present invention.
’
F igure.4. (a) is the N03' concentration measured using the spectrophotometer of the present
invention.
Figurc.4. (b) éhows the N03‘ Eoncgntration determined using Ion Chromatography of the
present invention.
Figurc.5. (a) is a production rate ofthe produced'NOs’ at different air flow rate and treatment
time in the present invention.
Figurc.5. (b) is the_ energy efficiency ofN03'production at different air flow rate and
treatment time in the present invention Figure.5. (c) is specific energy consumption ofN03'production at different air flow fate and
treatment time in the present invention. 0
Figure.6. shows the NH4+ concentration using a spectrophotometer in the present invention.
Figure.7. (a) is a plot showing the production rate ofthe produced NFL;+ at different air flow
rate and treatment time in the present invehtion.
Figure.7. (b)is the energy efficiency of NH4+production at different air flow rate and
treatment time in the present invention.
Figurc.7. (c) shows the specific energy consumption of NH4+producfion at different air flow
rate and treatment time in the present invention‘
Figure.8. (a) shows the pH values ofplasma-treated water samples in the present invention.
Figurc.8. (b) shows the total dissolved solids ofplasma-treated water samples in the present
invention.
Figure.8. (c) shows the conductivity of plasma-treated water samples ih the present
invention.
Figure.9.shows the temperéture of water during the plasma treatment in the present
invention.
,,
DETAIL DESCRIPTION OF THE INVENTION
_
The presént invention rel-atéshto effectively utili'zingthe‘thgrmal arc plasma to fix the
essential nitrogen components in water medium for the production of lqid fertilizer and
green ammonia for agriculture and sustainable energy appliéations, respectively. The présent
invention reducesthe usage of chemical fertilizers and reduces greenhouse gas emission. The
following detailed descriptidn enlightens the apparatus and methods for fixation of nitrogen
using (henna! arc plasma in a‘water medium.
Figure.1 illustrates a schematic diagram ofa submerged lthennal arc plasma apparatus
for the fixation of nitrogen components in water. The subllfierged themal aré plasma reac‘or
consists of six parts, (i) low péwerDix‘ect Current (DC)p]asma torch], (ii) 15 kW DC power
supply2,(iii) cooling water circulatorB, (iv) gas supply unit4, (v) stainless steel reactorS and
(vi) Temperature monitoring system & master controller 6which was interlinked With power,
.gas, water supply, and torch. The DC plasma torch consists ofa rod type cathode“, 12, and
nozzle type anode13, both are made of copper. Two electrodes were separated by ceramic
insulatorl4 and cooled by forced cooling water. For ignition of arc, a high voltage high
frequency (HVHF) igniter was applied between the electrodes, and the vortex generator 15,
16was positioned between the anode and cathode for the gas injection17,18, 19.
Figure. 2 illustrates the cross-sectiorial' view of the low—power DC thermal plasma
torch. In the present invention, a fixéd amounf of argon gas flow was used for are ignition of
the pilot arc. The gas flow rate was controll-ed by Rotameter7. Cooling water from chiller
8through the electrodes was maintained by controlling valves 20, 21,22, 23,and K-type
thermocouples were used to measure the temperature of the water flowing through the
electrodes. Plasma arc voltage and mutant :were measured by using a digital voltmeter and
ammeter installed on the master controller.
For a special case, the plasma tore}; wh’s mounteéi in the bottom of the stainless-steel
'
reactor, and R0 waterwas used to fill the rcactor for nitrogen fixation by fixing plasma
discharge power and gas flow rate‘During the précess, the arc gets ignitéd and produces free
electrons and ions, whiqh activates the air/nitrogen molecules by electron impact excitation,
ionization, and dissoéiation reactions. Hereinaextemal' feed gas (air/nitrogen) was directly
introducedinto the plasma jet 24, 25. In this present invention, the air/hitrogen plasma jet9
continuously interacts with the water molecules and it actiyates all possible active and
'reactive species. An active species reacts with nitrogen molecules, atoms, and ions
combinedwith dissociated water molecules (H20 —» H+.+ OH') to form nitrates and
ammonium.
In the present invention, production rate, energy efficiency, and specific energy _
consumption of produced N03' and NH? Were evaluated using the following formulas:
For N03" species:
_ [Molar concen-tration ofNO3] [Volume ofsolution] Production Rate (g/hr) — (1)
[Plasma treatment time]
Energy Efficiency (g/k\Vhr) = [Molar concentration ofN03] [Volume ofsolution] (2)
[Plasma Powetlasma treatment time] .
[Plasma Power] [Traeatmcnt time] (3)
[Molar concentration ofNO3]
Specific energy Consumption (GJ/Kg) =
For NH4+ species:
[Molar concentration ofNH4] [Volume ofsolution] (4)
[Plasma treatment time]
Production Rate (g/hr) =
Energy Efficiency (g/kWhr) = [Molar concentration ofNH4] [Volume ofsolution] . (5)
[Plasma Power][Plasma treatment time]
[Plasma Power] [Treatment time] (6)
[Molar concentration ofNH4]
Specific energy Consumption (GJ/Kg) =
Figure. 3 illustrates the optical emission spectra of argon/air plasma jet at a different
flow rate of air into the plasma torch. optical emission spectrometerllj is a promising tool and
it is a fast & non-destructive techniqué to investigate the kind of reactive species, atoms and
ions generated in the plasma medium with respect to operating conditions. The emission
spectrum ofthe piasma jet confirms the presence of N2* (Secbnd Positive System), N; (First
Negative System), N2*(First Positive System), NO, 0 and Ar species. The most dominant
N2* second positive system from C311u state to B311g state was observed at 280-405 nm
wavelength range and ifs formation is characteristic of electronic collisions in the nitrogen
‘
molegu‘les. The-presence of N; first negative system from 822.: state to X22; state was
confirmed at 390-427 nm aeléngth range. In addition, N2. first positive system from B3113
state to A321: state'appears in the wavelength range of 503-600 nm. The most expected NO
spectlzum from A22;r s:ate to XZH state was observed at'230-270 nm wavelength range. The
emission spectra clearly show the presence of atomic oxygen at 777 nm wqyelength and. the
Ar spectral lines at the wavelength range from 650~850 nm region. The presence of NO and
N2* (SPS) species in the plasma jet indicates that this condition is suitable and effective for
.the production of N03‘ and NH4+ i-n. this ihennal arc plasma torbh under submerged.
conditions‘ Increasing the air flow rate correspondingly increasing the electronic collisions in
the gas molecules thus leads to increéseé the intensity of NO and N2* (SPS) species in the
plasma jet. The nitrogen fixation rate'in the waier mediLim increases with the increase ofinlet
airflow rate. Furthennore; electron §ex11perature and electron number density ofthe plasma jet
at anode nozzle exit was estimated by using emission spectra and the values are 7058 K and
2.33 x 10'6 cm‘3 respectively.Plasma jet length is varied from 60-150 mm with respect to the air flow rate and plasma
discharge power. The longer plasma jet favors increasing interaction volume as well as
reaction rate.
N2+é'—> 2N+e'
W's-wing
N2*+e'—>2N+e'
a
H20+e‘—>H++OH'+e'
N+OH'—>NO'+H+
NO + OH“—> N02‘ + H+
N02 + OH' —> N0; + H“
-. 2N0; + H20 ~-> NQZ' + N0; + 2H+
_
N0 + NO; + H20 —+ ZNOZ' + 2H+
V
(7)
_
(8)
(9)
(10)
(H)
(lé)
(13)
(14)
(15)
During the thermal arc disgharge with air: energetic electrons, active nitrogen, and
oxygen species were formed due to ele'btron impact collision of air molecule. Moleéules like
oxygen and nitrogen gets excited, ionizgd, and dissociated. Water molecules get dissociated
into HT and OH' ions and it was activated by energetic free' electrons, excited nitrogen.
species, and oxygen Species from the plasma. Consequently, excited nitrogen species like N2*
directly reacts with water to fix the nitrogen compounds such as NHf'and NO3‘ by the
reduction and oxidation phenomenon. The most prominent pathways for NO formation are
‘he Zeldovich mechanism, in which ex'cited nitrogenspecics réact with OH species to fonn
CHEHNAE 21 IB‘9!2»(323--12=129
nitrogen compounds like NO.~NO gets oxidized to from N02' and then N03" further oxidized
into N03'.
Herein, the excited nitrogen species and hydrogen radicalproduces the NH+
molecules, which acted as the halfway to form ammonium. Further, the short-lived NH+
‘
molecules react with HAW-12+ (or) hydrogenated to form NH4+.
e'4N2'—»N+Nfrve"- 4
'
_ (16)
11.20. + e' —» H“ + OH'+Ie'
‘
'
(17)
N*+Hz*—»NH*+H+
(18)
N++H+—>NH+
(19)
~
N; + H+ —> NH+ + N+
'
. (20)
‘
N+ + H; —> NH; (21)
NH+ + H; 41m; + H+
I
. (22)
NH” + H+ —»NH2*
. (23)
NH; + H2*—> NH; + ii“
.
(24)
NH; +143" _. NH;+
'
‘
_ (25)
NH3++H;'—>NH4*+ if ’
.‘
~
'
'
'
'
(26)
NH; + H*'—> NH} ‘. ‘
>
. (27)
e'*+Oz;—>O¥O+e'
(28)
ov+c.)2—>o3 -
I
.. ~ ~. (29).
e'* + 02 —» 02* + e'
‘ I
>
(30)
02*+02—»03+0 ' ‘~ (31)
’e‘+0g~0+02+.e“ "
(32)
Oxygen molecules from air get dissociated by electrons leading to the generation of
atomic oxygen and ozone by the inter action of both the atomic and molecular oxygen.
Ar* + H20 —» Ar +‘OH + H
‘ '
(33)
When argon gas is used for the ignition ofthe plasmajet, the excited argon dissociates
water molecules into hydrogen and hydroxyl radical.
Figure. 4. (a) and (b) illustrates the concentration of NOfwhich is produced by the
submerged thermal arc plasma reactor. The amount of N03' preselit in the plasma processéd
water medium was measured by ion chromatography and UV-spectrophotometerand both the
results shows similar trend in N03' concentration. The concentration of N03‘ increased with
respect to increasing the air flow rate as well as treatment time. Interestingly, NOz' (nitrite)
free NO3' (nitrate) was produced in this submerged thermal arc plasma reactor, which was
favoured for liquid fertilizer application in the agriculture sector. Since NO;‘ was toxic in
nature and cannot be absorbed by plants. In agriculture point of view, N02" free liquid
fertilizer plays a major role in inducing or accelerating the plant growth as well as yield. N03'
as a nitrogen fertilizer it can enhance the soil quality as well as crops production rate. Hence,‘
this submerged thermal arc plasma method is feasible approach for the fixation of N03‘ in
water to produce liquid fertilizer.
In general, nitrite is unstable as well as short-lived species, so it immediately
undergoes oxidization, and finally, nitrate is formed. In addition to that, If the pH of the
soiuti'on is below 3.5, leads to complete conversion of nitrate from nitrite and or NO;‘ can
react with OH to fonn N03' and H30 as shown in the equation (35).
3Noz' + 2H*'—) 2N0 + No; {H20
‘
(34)
N02'+ 20H —’ NO3’ + H20 . (35)
In the present invention, the concentration of NOg‘varied from 428 to 1252 PPM with respect to increasing the air flow rate, and the treatment time:
Figure. 5. (a) illustrates the production [ate ofNOj under‘diffcreljt air_ flow rate and
treatment time. The production rate, was calculated by the proddct of N03‘ cfillcentration, and
the volume' of water by treatment tjme shown in equation (1). As seen in Figure 5.
(a),production rate of NO3' varies from 5.4 (0 25.7 g/hr while increasing the treatment time
and _air.flow rate.
Figure. 5. b) ill‘ust‘rates the energyefficiency of the produced NO3' was calculated by .
'
using the production rate byplasmé powelj shown in equation (2). Energy efficiency increases
from 1.2 to 4.5 g/kWhr while increasingthe air flow rate.
Figure. 5. c) illustrates the specific energy 90115umption for the firoduction of N03"
which was calculated by the product of plasma power and treatment time by N03"
concentration shown in equation (3).Overall results clearly states that the present invention
i.e. submerged thermal arc plasma reactor is one of the energy efficient and eco-friendly
method for the fixation of nitrogen component N03" in a liquid medium. Furthermore, the
optimization of processing parameters such as gas feed rate, treatment time, proper solution A
‘
circulation and thermal management can enhance the nitrogen fixation rate with substantial
energy efficiency.
Figure. 6 illustrates the concentration of NH4+ ions produced bysubmerged thermal
arc plasma reactor.The concentration of NH4+varied from 130 to 320 PPM with irrespective
of gas flow rate and treatment time.
Figure. 7. 3) illustrates the production rate of NH4+ which was calculated by the
product of Nl-L;+ céncentration and volume of water by treatment time was shown in equation
(4). The production rate of NI-L.’r varies from 2.1 to 17.7 g/hr. It is observed that the
production rate decréases while increase the air flow rate and treatment time. Low air‘flow
rate (5 LPM) and short treatment time (10 minutes)is the optimum condition for the better
production of NH4+.
Figure. 7. h) illustrates the energy efficiency of NH; production by submerged
thermal arc plasma. Similar to the production ,rate, increases in air flow rate and treatment
-
time, decrease the energy efficiency and it vafies from 0.39 to 3.9 g/kWhr..
Figure. 7. c) illustrates. the specific energy consumption for he production of NH4+
which was calculated by the product of plasma power and ‘treatment fime by NH4+
concentration was shown In eiquation (6). The finest condition for the synthesis ofNI-h using
a submerged thermal arc plasma reactor was_ 5 LPM of air flow rate and 10 minutes of
treatment time. Interestingly compared with previodsly reported results this method 'required
less energy for 'he effective synthesis of NH4+ under atmospheric pressure conditions.
Figure. 8. 9) illustrates the pH of plasma-treated water with respect to treatment time.
The continuous interaction of plasmat with water resullts in strong aéidification. Herein, the
pH of the plasma-treated water decreases from its initial value of 6.8 with increasing in_
treafmem time. The decreases in pH were due-to the formation of nitrous acid and some
intermediate compounds.
Figure. 8. b) illustrates the total dissolved solids content versus treatment time graph.
During plasma treatment, excited nitrogen and oxygen species readily dissolve in the water,
which itself alters the conductivity. Consequently, total dissolved solids concentration
increases with increasing the treatment time due to reactive species dissolved in plasma
treated water.
Figure. 8. c) illustrates the variation in electrical conductivity of submerged thermal
arc plasmatreated water as a function of treatment time. Electrical conductivity is a tendency
of water tovfacilitate electric current flows through it and the presence ofmore active ions in
plasrha treated water greatly influences the conductivity.
~
Figure. 9 illustrates the raise of water medium temperature during the plasma
treatment. Increasing the treatment time correspondingly Increases the water temperature due
to joule heating effect and the fraction of heat released by the exothennic reaction
Meanwhile, the continuous interaction of plasma with water results 1n vaporization of water
molecules. In this process, water loss due [0 the vaporization is varied from 3 to 4 %.
In the present invention, the formation of hydrogenperoxide (H202)in the aqueous
solution initiatéd by the recombination of hydroxyl radicals (OH) Was easily decomposed du‘e
(to high temperature of thermal plasma. Hence, instead of OH recombination, preferably, the
nitrogen speci_es react with hydroxyl radical to form nitrous acidequation (35). Here, the
absence of H202 In the plasma- treated water which was confirmed by using semi- quanlimtive
test strips.
Hydrdxy] radical acts as an oxidizing agent, which is impoftahtfor the production of NO;
and NH4+ in this process. Thc concentration of hydroxyl radicals w-as quantitatively analysed
by the terephthalic acid (TA) probe methodto understand the formation mechanism as shown
in the equations (11- 15)&(33) Estimated concentration of hydroxyl radical p1esent in the
plasma- treated water ranged from 6 to to umol. Similarly, the ozone dissolved in the
plasma- treated water is considered an effective oxidant and it was measured by the indigo
blue method. The prepared indigo reagent was mixed with plasma-treated water and the
labsorbance was taken at 600 nm using a spectrophotometer. About 0.2 - 0.75 mg/L of ozone
was observed in the plasma-treated water, which influences the formation ofN03' and NH4+.
The antimicrobial activity of submerged thennal arc plasma processed liquid fenilizer
was investigated by
'
using Escherichia coli and Pseudo'nwnas qeruginosa bacteria.
Experimental observation shows that there was a considerable bacterial growth similar like a
control plate (Chloramphenicol) in the agar plate 'added with processed liquid
fenilize'rHerein, the absence of H202 and N02' in the liquid fenilizer, leads to the
inactivation ofthe antimicrobial propeny. Numerous works clearly described that the plasma-
treated water has antimicrobial activity but, this present invention does not show
antimicrobial activity. Henceg'the fixation of nitrogen components by submerged thermal arc
plasma is one of the potential approaches for the production of liquid fertilizers. Since this
present invention focused on the fixation of nitn'te-free nitrogen component and it won’t
pollute the soil and microorganism, hence this liquid fertilizer can- be claiming ans anecofriendly
fertilizer for agriculture application.
We conclude that the submerged themal arc plasma fixatjon of nitrogen component
become a potential approach for synthesis of liquid fertilizer and green ammonia without the
support of catalysts. In the embodiment of the present invention, a novel submerged thermal
arc plasma nitrogen fixation apparatus and the method have been disclosed. The present
invention can be utilized in numerous applications such as agriculture, chemical industries,
medical application,'dyes, textiles, etc.
WE CLAIM:
l. A device for the fixation of nitrogen components by using a submerged thermal are
10.
1].
plasma reactor compn'éing:
.
a) low-power (~5-10 kW) direct current themml plasma torchl.
b) 15 kW DC power supply 2.
c) cooling water circulator 3.
d) gas supply unit 4.
6) stainless steel reactor 5.
0 temperature monitoring system & master controller 6 which was interlinked with
power, gas, water supply, and torch.
The device of claim 1 in which the above said low power direct current plasma torch
The device of claim 1 in which the above said_ !ow power direct current hollow
cathode and nozzle type anode plasma torch
The device of claim 1 in which the above said plasma torch electrodes design was
optimum for the better arc stability under submerged cpliditions.
The device of claim 14in which above said reactor Chamber was cylindricaishape.
The device of claim 1 in which a low-power thermal érc plasma torch is fixed in the
bottom or top or middle .ofthe reactor.
The device of claim 1 in which a low-power thenfial ,arc plasma torch for batch
_
process and continues process.
The device of claim 1 in which ‘a low-power thermal‘arc .plasma torch with plasma
forming gas(air/nitrogen) which directly introduce into the plasma tprch.
.
The device of claim 1 in which a low-power thermal arc plasma torch along with
ex‘ernal gas feeder (air/nitrogen) which directly introduce into the plasma medium.
A method of thermal érc plasma fixation of nitrogen combonents in liquid medium
using air/nitrogen and water or puré nitrogen and wziter as a source of nitrogen and
hydrogen respectively at atmospheric pressure using submerged thefinal arc plasma
reactor.
'
_
The method of claim 9 in which nitrite-free nitrdgen-based liquid feltilizer is
produced.
. The method of claim 9 in Which a higher production rate and energy efficiency were
achieved using submerged thérmal arc plasma reactor.
13. The method of claim 9 in which submerged thermal arc plasma produced liquid
fertilizer do':s not Show antimicrobial activity. Hence, by using this liquid fertilizer,
the crops production rate should be accelerated without killing soil—bound microorganisms.
, ,
14. The fiethod of claim 9 if: which submerged thérmal arc_-plasrha produced green
ammonia (NH4+) by cracking air/nitrogen and water molecules.
15. The method of claim 9 in which submerged thermal arc plasma produced ammonia
(NH4+) with high production rate,
16. The method of claim 9 in which submerged thermal arofilafima produced green ammonia (NI-14+) without the suppon of catalyst.