FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION: -A METHOD OF MANUFACTURING OF DIESEL EXHAUST FLUID (“DEF”) FROM UREA SOLUTION AND NITROGENOUS AEROSOL PARTICULATE
AND USES THEREOF

FIELD OF THE INVENTION
This invention relates to the Energy efficient method to manufacture Diesel Exhaust Fluid (“DEF”) from urea solution and Nitrogenous aerosol particulate matter containing nitrogen with de-ionised water at Urea Plant. The manufacturing process provides simple energy efficient operating process for DEF manufacturing, which is useful for reducing the level of nitrogen oxides (NOx) emissions during combustions.
BACKGROUND OF THE INVENTION
At present, DEF is being manufactured by either of three following precursors [1] i.e. urea prills, dry flashed urea crystals and concentrated urea solution, all of these precursors use the de-ionized water to obtain the DEF. The major limitation of the existing process is using the single feed i.e. urea prills, or urea crystal or urea solution also called Aqueous Urea Solution (AUS 32) [2].
WO/2018/011327; PCT/EP2017/067657 discloses a method for
producing an NOx reductant AUS 32 solution (diesel exhaust fluid) comprising at least the mixing of water and a particulate composition containing (i) urea; and an additive comprising component (ii): (ii) combination of at least one polymer or oligomer containing amino groups and

at least one functionalized polyvinyl compound; wherein the weight percentage of component (i) in the particulate composition is greater than 60 wt% and the weight percentage of component (ii) in the particulate composition is less than 1 wt% and wherein a urea solution is obtained and the weight percentage of component (i) in the obtained urea solution is between 31 wt% and 34 wt%.
EP 15162515; 3075436 discloses Formulations of diesel exhaust fluid ("DEF") that include one or more functional additives and the use of such formulations for reducing deposits in the exhaust systems of engines that use DEF requiring Selective Catalytic Reduction ("SCR") catalysts are described.
It is well known that recycling of nitrogenous aerosol particulate matter, containing nitrogen, in urea plant is energy intensive method to produce urea prills. The principal use of urea is providing nitrogenous fertilizer to agriculture crops. Furthermore, globally majority of the countries dealing with energy poverty and air pollution.
In summary, the existing processes (details provided below as example) to manufacture the DEF has drawback by using aforementioned precursors are

a) requires high energy and resources to manufacture dedicated quantity of urea for producing DEF;
b) while producing urea, the manufacturing plant emit NOx during steam generation for usage to dissolve the recovered nitrogenous aerosol in urea plant. It means that the plant first generates the NOx and then produce the material as DEF to control NOx generated as a result of diesel engine combustion.
c) Nitrogenous aerosol emitted from PCS further increase the pollution load in Urea Plant.
At present, the DEF is being manufactured by dissolving the urea prill /urea solution/ dry flashed urea crystals in de-ionized water as shown at Figure 1 as per quality specified at Reference-5.
All mode of DEF manufacturing is shown at Reference-4. Shelf life of DEF is a function of storage temperature [Reference-6], hence to achieve the optimal DEF storage temperature is the main energy consumption step in DEF manufacturing which entirely dependent on the process route. DEF shall be stored and shipped at a temperature not more than 25¬°C. To achieve the optimal temperature, refrigeration unit and proper mixing of nitrogenous

aerosol particulate matter containing nitrogen with de-ionised water is essential step.
None of the prior art indicate above either alone or in combination with one another disclose what the present invention has disclosed.
Therefore, the present invention discloses a novel manufacturing process of the DEF from urea solution along with a by-product of urea manufacturing process i.e. nitrogenous aerosol particulate matter containing nitrogen.
SUMMARY OF THE INVENTION
This invention relates to the Energy efficient method to manufacture Diesel Exhaust Fluid (“DEF”) from urea solution and Nitrogenous aerosol particulate matter containing nitrogen with de-ionised water at Urea Plant. The manufacturing process provides simple energy efficient operating process for DEF manufacturing, which is useful for reducing the level of nitrogen oxides (NOx) emissions during combustions. This method helps to reduce the recycling energy of nitrogenous aerosol particulate matter containing nitrogen in the urea plant. The manufacturing process provides simple energy efficient operating process for DEF manufacturing, which is useful for reducing the level of nitrogen oxides (NOx) emissions during combustions. The major

advantages with this innovative validated process is reducing the NOx emission at the very first place right during the manufacturing process of urea and then producing a value added product, DEF from nitrogenous aerosol waste to reduce NOx emission from vehicular combustion.
The present method involves the following steps:
Step 1
Collection of Demineralised (DM) water in tank and pumping of same to Electrodeionisation (EDI) Unit for removal of traces quantity of contaminants to produce Deionised (DI) water.
Step 2
Lowering of DI water temperature by chiller Unit and pumping of same to Pre-Mix Chamber.
Step 3
Collection of Urea solution (80% conc.) from Pre-evaporator outlet line in Urea Solution Tank and pumping of same to Pre-mix chamber.
Step 4

Collection of well mixed urea solution and DI water in Intermediate Tank to achieve the urea concentration to form DEF.
Step 5
Pumping of raw DEF to Bender Tank and adding the urea aerosol from Urea dust feeder to achieve urea concentration of 32.5 % in DEF and desired solution temperature.
Step 6
Pumping of DEF solution to three- stage Ultra Filtration Unit to remove unwanted impurities from the Final DEF Solution.
Step 7
Storage of final DEF solution at recommended temperature in DEF storage Tanks.
Step 8
Packaging and loading of final DEF solution in buckets, Intermediate Bulk Container (IBC) and Road tankers and dispatch of same to vendors.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: Existing method and/or modes of the DEF manufacturing

Figure 2: Energy Efficient DEF manufacturing process at IFFCO Kalol Figure 3: Flow chart of the present method
DETAILED DESCRIPTION OF THE INVENTION
The present invention discloses a novel and energy efficient manufacturing process of Diesel Exhaust Fluid (DEF) from urea solution and nitrogenous aerosol, one of the by-products of urea plant with de-ionised water, suitable for the abatement of NOx in Diesel engine exhaust gases that use DEF for the Selective Catalytic Reduction (“SCR”) catalysts. This method helps in recycling some of the nitrogenous aerosol containing nitrogen collected from exhaust air of Prill Cooling System (PCS) at urea plant. The brief note on Nitrogenous aerosol generation at the urea plant is given at Appendix-I. This method is useful for reducing the level of nitrogen oxides (NOx) emissions with the uses of nitrogenous aerosol, which may require additional utilities for recycling for manufacturing of urea prills. Hence, DEF will reduce the NOx level at diesel engine exhaust gases and raw material used for DEF manufactured will also reduce the NOx emission with this noble process.
DEF is non-hazardous aqueous solution of 32.5 % urea (w/w) and balance 67.5% de-ionized water. Small quantities of DEF is injected into the exhaust

upstream of catalyst, where it vaporizes and decomposes to form ammonia and carbon dioxide as under:

In urea plant, urea solution from flash tank flows to pre-evaporator and subsequently sent to urea solution buffer tanks. The typical analysis of urea solution buffer tanks is as under:

The urea solution from buffer solution tanks is filtered and then it is concentrated in two evaporators installed in series to produce melt urea which is pumped to the top of Prill tower. The urea prills formed in the Prill tower are collected at the base of tower and transfers to Fluidized Bed Cooler (FBC) of Prill Cooling System (PCS). At the outlet of PCS, Neem oil is sprayed over urea prills for coating. The neem coated urea material is conveyed to Bagging

Plant after cooling in fluidized bed cooler of Prill Cooling System (PCS) with atmospheric air and neem oil coating.
Nitrogenous aerosol particulate matter collected from PCS is mixed with DM water to make urea solution of about 70% concentration and pumped to urea solution tank by urea solution buffer tanks for further processing to produce urea prills. Low pressure (LP) steam is used to maintain the solution temperature to avoid crystallisation. Therefore, this cycling step is energy intensive and a source of product contamination in Urea Plant.
At present, DEF is being manufactured by either of three following precursors [1] i.e. urea prills, dry flashed urea crystals and concentrated urea solution, all of these precursors use the de-ionized water to obtain the DEF. The major limitation of the existing process is using the single feed i.e. urea prills, or urea crystal or urea solution also called Aqueous Urea Solution (AUS 32) [2].
It is well known that recycling of nitrogenous aerosol particulate matter, containing nitrogen, in urea plant is energy intensive method to produce urea prills. The principal use of urea is providing nitrogenous fertilizer to agriculture crops. Furthermore, globally majority of the countries dealing with energy poverty and air pollution.

In summary, the existing processes (details provided below as example) to manufacture the DEF has drawback by using aforementioned precursors are
a) requires high energy and resources to manufacture dedicated quantity of urea for producing DEF;
b) while producing urea, the manufacturing plant emit NOx during steam generation for usage to dissolve the recovered nitrogenous aerosol in urea plant. It means that the plant first generates the NOx and then produce the material as DEF to control NOx generated as a result of diesel engine combustion.
c) Nitrogenous aerosol emitted from PCS further increase the pollution load in Urea Plant.
Therefore, the present invention discloses a novel manufacturing process of the DEF from urea solution along with a by-product of urea manufacturing process i.e. nitrogenous aerosol particulate matter containing nitrogen. This method helps to reduce the recycling energy of nitrogenous aerosol particulate matter containing nitrogen in the urea plant. The manufacturing process provides simple energy efficient operating process for DEF manufacturing, which is useful for reducing the level of nitrogen oxides (NOx) emissions

during combustions. The major advantages with this innovative validated process is reducing the NOx emission at the very first place right during the manufacturing process of urea and then producing a value added product, DEF from nitrogenous aerosol waste to reduce NOx emission from vehicular combustion.
At present, the DEF is being manufactured by dissolving the urea prill /urea solution/ dry flashed urea crystals in de-ionized water as shown at Figure 1 as per quality specified at Reference-5.
All mode of DEF manufacturing is shown at Reference-4. Shelf life of DEF is a function of storage temperature [Reference-6], hence to achieve the optimal DEF storage temperature is the main energy consumption step in DEF manufacturing which entirely dependent on the process route. DEF shall be stored and shipped at a temperature not more than 25°C. To achieve the optimal temperature, refrigeration unit and proper mixing of nitrogenous aerosol particulate matter containing nitrogen with de-ionised water is essential step.
During normal plant operation, a typical urea plant produce about 10 MT per day of nitrogenous aerosol , which need to be recycle and re process to urea

prill. Recycling of Nitrogenous aerosol containing nitrogen requires the utilities as under:

urea
Therefore, any quantity of nitrogenous aerosol containing nitrogen used for the DEF manufacturing will directly improving the Urea Plant performance and this process route for DEF manufacturing shall be energy efficiency route as shown in Figure 2.
Nitrogenous aerosol containing nitrogen recycling involved direct, but significant reduction in energy consumption in the urea manufacturing industries, but also reducing environmental (air and water) pollution at the very first place. Therefore, DEF solution preparation with urea solution and Nitrogenous aerosol will be optimal process route to manufacture the DEF on industrial scale as shown at Figure 2.
As, nitrogenous aerosol recycling is one of the main known source of contamination at the Urea Plant. Hence, any reduction in Nitrogenous aerosol recycling will improve the urea product quality and will save the re-

processing utilities in urea plant. Hence, IFFCO Kalol Unit have initiated implementation of in-house DEF manufacturing Unit using the urea solution and Nitrogenous aerosol along with de-ionised water at Urea Plant.
Appendix-I
Fluidised Bed Cooler(FBC) is installed at Prill Cooling System (PCS) of Urea plant to cool the urea prills with ambient air. Hot urea prills from bottom of prill tower flows into the FBC by belt conveyor. About 2,16,000 m3/h atmospheric air is supplied at bottom of the FBC by motor driven fan. During fluidisation on perforated plate of FBC, heat of hot prills is taken away by air and cooled urea prills at 55°C flows over the weir to product conveyor and Neem oil is sprayed over urea prills on product conveyor to convert normal urea to neem coated urea.
Exhaust air of FBC at temperature of about 66.5°C passes through cyclone separators (10 Nos.) to remove nitrogenous aerosol or particulate matter. After removing nitrogenous aerosol particulate matter, exhaust air with 50 mg/NM3 particulate matter is vent to atmosphere by motor driven exhaust air fan. The nitrogenous aerosol particulate matter separated in the cyclone separators is collected in the three silos. From silo, nitrogenous aerosol particulate matter is transferred to belt conveyor with the help of rotary valves. All the silos are

provided with electric vibrators operate at fixed time interval to make the particulate matter fall easier.
Nitrogenous aerosol particulate matter from the conveyor belt is transferred to dissolving tanks and DM water is used to make the urea solution. The tanks are equipped with LP steam heated coil to maintain the solution temperature. Urea solution at about 70% urea solution is transferred to urea solution tank by urea solution transfer pumps for further processing to produce urea prills. About 10-12 MT per day nitrogenous aerosol particulate matter is being generated at urea plant load of about 1780 MTPD.
References
1. Integrated Production of Urea for Diesel Exhaust Fluid and Urea Ammonium Nitrate. Patent No: WO2016/153354 A1
2. Use of a urea composition to produce diesel exhaust fluid (AUS 32) Patent No: AU2017297784A1
3. Diesel Exhaust Fluid Formulation that reduces urea deposits in exhaust system. Patent: US 2014/03699.11 A1
4. Stamicarbon web site: [www.stamicarbon.com]
5. ISO 22241-1; 2019-02; [https://www.iso.org/obp/ui/#iso:std:iso:22241:-1:ed-2:v1:en]

6. ISO22241-3;Table-3, page-4, 2017; https://www.iso.org/obp/ui/#iso:std:iso:22241:-3:ed-2:v1:en]
7. IFFCO’s Internal communications

We Claim:
1. A method of manufacturing of Diesel Exhaust Fluid (“DEF”) from urea solution and Nitrogenous aerosol particulate matter containing nitrogen with de-ionised water comprising the steps of;
Collecting of Demineralised (DM) water in tank and pumping of same to Electrodeionisation (EDI) Unit for removal of traces quantity of contaminants to produce Deionised (DI) water;
Lowering of DI water temperature by chiller Unit and pumping of same to Pre-Mix Chamber;
Collecting of Urea solution (80% conc.) from Pre-evaporator outlet line in Urea Solution Tank and pumping of same to Pre-mix chamber;
Collecting of well mixed urea solution and DI water in Intermediate Tank to achieve the urea concentration to form DEF;
Pumping of raw DEF to Bender Tank and adding the urea aerosol from Urea dust feeder to achieve urea concentration of 32.5 % in DEF and desired solution temperature;

Pumping of DEF solution to three- stage Ultra Filtration Unit to remove unwanted impurities from the Final DEF Solution and Storing of final DEF solution at recommended temperature in DEF storage Tanks.
2. The method as claimed in claim 1, wherein Fluidised Bed Cooler(FBC) is installed at Prill Cooling System (PCS) of Urea plant to cool the urea prills with ambient air.
3. The method as claimed in claim 1, wherein hot urea prills from bottom of prill tower flows into the FBC by belt conveyor and 2,16,000 m3/h atmospheric air is supplied at bottom of the FBC by motor driven fan.

4. The method as claimed in claim 1, wherein during fluidisation on perforated plate of FBC, heat of hot prills is taken away by air and cooled urea prills at 55°C flows over the weir to product conveyor and Neem oil is sprayed over urea prills on product conveyor to convert normal urea to neem coated urea.
5. The method as claimed in claim 1, wherein Exhaust air of FBC at temperature of about 66.5°C passes through cyclone separators (10 Nos.) to

remove nitrogenous aerosol or particulate matter; and after removing nitrogenous aerosol particulate matter, exhaust air with 50 mg/NM3 particulate matter is vent to atmosphere by motor driven exhaust air fan.
6. The method as claimed in claim 1, wherein said nitrogenous aerosol particulate matter separated in the cyclone separators is collected in the three silos; and from silo, nitrogenous aerosol particulate matter is transferred to belt conveyor with the help of rotary valves; further all the silos are provided with electric vibrators operate at fixed time interval to make the particulate matter fall easier.
7. The method as claimed in claim 1, wherein said Nitrogenous aerosol particulate matter from the conveyor belt is transferred to dissolving tanks and DM water is used to make the urea solution.
8. The method as claimed in claim 1, wherein tanks are equipped with LP
steam heated coil to maintain the solution temperature; and Urea solution at
70% urea solution is transferred to urea solution tank by urea solution transfer
pumps for further processing to produce urea prills.

9. The method as claimed in claim 1, wherein 10-12 MT per day nitrogenous
aerosol particulate matter is being generated at urea plant load of about 1780
MTPD.
10. The method as claimed in claim 1, wherein Low pressure (LP) steam is
used to maintain the solution temperature to avoid crystallisation.