Aonla

Located near the city of Bareilly, the IFFCO Aonla facility has always been a front runner when it comes to environmental concerns. It is known for adopting the most stringent measures to maintain ecological balance

BRIEF REPORT ON ENERGY CONSERVATION

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During the fiscal year 2017-18, Aonla unit has kept up its performance on various fronts and achieved new records & milestones in the field of energy & production, and received numerous awards in the fields of Energy Efficiency, Safety, Environment and HR during this period.

Details of the performance achieved on various fronts are as given below:

Description Unit Aonla-I Aonla-II Aonla-I+II
Ammonia plant:
Production Lakh MT 5.108 5.334 5.334
Capacity Utilisation % 88.96 88.96 90.93
On-stream days Days 297.0 307.2 302.1
Urea plant :
Production Lakh MT 8.959 9.306 9.306
Capacity Utilisation % 89.60 93.07 91.33
Capacity Utilisation Gcal/MT 5.344 5.224 5.283
On-stream days Days 292.7 298.2 295.5
Urea despatch Lakh MT 8.980 9.334 18.324

PRODUCTION PERFORMANCE – TARGET (2017-18) VS ACTUAL

Description Unit Target Actual Production
Ammonia Lakh MT 10.06 10.44
Urea Lakh MT 17.63 18.26

PRODUCTION TARGETS FOR 2018-2019 & 2019-2020

Description Unit 2018-2019 2019-2020 (Estimate)
Ammonia Lakh MT 12.2 12.2
Urea Lakh MT 21.4 21.4

SPECIFIC ENERGY CONSUMPTION TREND

MANPOWER PRODUCTIVITY (AONLA-I+II)

Total Manpower employed Urea production (MT) Per Capita Output (MT)
780 1826474 2342 (FY- 2016-17 : 2579)

HIGHLIGHTS OF THE YEAR 2017-18

During the year 2017-18, Aonla Unit has achieved new records in the fields of energy & production and achieved many new milestones as given below:

NEW RECORDS (16 nos.)

Aonla-I

*   New Record-1: Ever highest daily Ammonia production record of 1935 MT achieved on 17.03.2018 against previous record of 1915 MT achieved on 01.02.2015.

*   New Record-2: Ever highest daily urea production record of 3730 MT achieved on 02.12.2017 against previous record of 3660 MT achieved on 30.10.2012. The previous record was surpassed 3 times during the financial year.

*   New Record-3: Ever highest Monthly Ammonia production record of 59248 MT achieved in March, 2018 against previous record of 58914 MT achieved in January, 2015.

*   New Record-4: Ever lowest monthly (B.L.) energy consumption record of 7.061 Gcal/MT ammonia achieved in March, against previous record of 7.430 Gcal/MT ammonia achieved in October, 2014. The previous record was surpassed 5 times during the financial year.

*   New Record-5: Ever lowest monthly energy consumption record of 5.039 Gcal/MT urea achieved in March, 2018 against previous record of 5.404 Gcal/MT urea achieved in November, 2014. The previous record was surpassed 6 times during the financial year.

*   New Record-6: Ever lowest yearly (B.L.) energy consumption record of 7.320 Gcal/MT ammonia achieved in F.Y. 2017-18 against previous record of 7.631 Gcal/MT ammonia achieved in F.Y. 2012-13.

*   New Record-7: Ever lowest yearly energy consumption record of 5.344 Gcal/MT urea achieved in F.Y. 2017-18 against previous record of 5.570 Gcal/MT urea achieved in F.Y. 2015-16.

Aonla-II

*   New Record-8: Ever lowest monthly (B.L.) energy consumption record of 6.954 Gcal/MT ammonia achieved in December, 2017 against previous record of 7.173 Gcal/MT ammonia achieved in March, 2017. The previous record was surpassed 3 times during the financial year.

*   New Record-9: Ever lowest monthly energy consumption record of 4.996 Gcal/MT urea achieved in March, 2018 against previous record of 5.217 Gcal/MT urea achieved in March, 2017. The previous record was surpassed 5 times during the financial year.

*   New Record-10 Ever lowest yearly (B.L.) energy consumption record of 7.169 Gcal/MT ammonia achieved in F.Y. 2017-18 against previous record of 7.333 Gcal/MT ammonia achieved in F.Y. 2015-16.

*   New Record-11: Ever lowest yearly energy consumption record of 5.224 Gcal/MT urea achieved in F.Y. 2017-18 against previous record of 5.308 Gcal/MT urea achieved in F.Y. 2015-16.

Aonla-I+II

*   New Record-12: Ever highest monthly urea production record of 204782 MT achieved in March, 2018 against previous record of 203735 MT achieved in December, 2012.

*   New Record-13: Ever highest monthly urea despatch (By Rail) record of 182585 MT achieved in March, 2018 against previous record of MT achieved in May, 2015.

*   New Record-14: Ever lowest monthly energy consumption record of 5.018 Gcal/MT urea achieved in March, 2018 against previous record of 5.329 Gcal/MT urea achieved in December, 2014. The previous record was surpassed 6 times during the financial year.

*   New Record-15: Ever lowest yearly energy consumption record of 5.283 Gcal/MT urea achieved in F.Y. 2017-18 against previous record of 5.440 Gcal/MT urea achieved in F.Y. 2015-16.

*   New Record-16: Continuous accident free days record of 2253 days achieved from January, 2012- March, 2018 against previous record of 1521 days achieved from August, 2007- October, 2011.

NEW MILESTONES (5 nos.)

Aonla-I

*   New Milestone-1: Milestone of 26 million MT Urea production achieved on 21.04.2017.

*   New Milestone-2: Milestone of 26 million MT Urea despatch achieved on 23.04.2017.

Aonla-I+II

*   New Milestone-4: Milestone of 27 million MT Ammonia production achieved on 12.12.2017.

*   New Milestone-5: Milestone of 46 million MT Urea production achieved on 25.10.2017.

*   New Milestone-6: Milestone of 46 million MT Urea despatch achieved on 27.10.2017.

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Following schemes have been implemented during turnaround of Aonla-I Unit, Aonla-II Unit and Power Plant in the complex:

Aonla-I

Scheme 1: Replacement of existing GV solution based CO2 removal section by aMDEA solution based CO2 removal section for less energy requirement.
Original System:

In CO2 removal section of Ammonia-I plant, GV solution (a hot potassium carbonate solution) was used to absorb CO2 from process gas in CO2 Absorber. CO2 rich GV solution was regenerated in two stages i.e. in 1st Regenerator and then in 2nd Regenerator. CO2 gas separated was then sent to Urea plant for the production of urea. The source of regeneration energy was process gas and LP steam. Regenerated GV solution was again sent to CO2 Absorber to absorb CO2 from process gas.

CO2 content in the process gas at the exit of CO2 Absorber: 500 ppm. Regeneration energy required: 830 kcal/NM3.

Modified System:

The GV solution based CO2 Removal section has been replaced by aMDEA solution based CO2 Removal section. A new Bulk Absorber in addition to existing CO2 Absorber is being used to absorb CO2 in aMDEA solution from process gas. CO2 rich aMDEA solution is being regenerated in three stages, firstly in HP Flash Vessel, then in LP Flash Vessel and finally in CO2 Stripper. The source of regeneration energy is only process gas. CO2 separated is being sent to Urea plant for the production of urea and regenerated aMDEA solution again sent to CO2 Absorber to absorb CO2 from process gas.

CO2 content in the process gas at the exit of CO2 Absorber: <= 500 ppm Regeneration energy required: 460 kcal/NM3 With decreased regeneration energy requirement in CO2 Removal section and better CO2 removal in CO2 Absorber, steam to carbon ratio at Primary Reformer inlet has been decreased to 3.0. This has resulted in reduction of front-end pressure drop and also saving of HP steam at turbine drive of Synthesis Gas Compressor.

Scheme 2: Replacement of HP boiler at downstream of High Temperature Shift Converter with new steam super-heater
Original System:

At the outlet of High Temperature Shift Converter, process gas heat was utilized to generate HP steam in Waste Heat Boiler. HP steam generated in Waste Heat Boiler, RG boiler in front end and Back end boilers was then superheated in Auxiliary Steam Superheater where NG fuel is fired.

Modified System:

HP steam requirement shall be less due to implementation of Energy Saving schemes i.e. revamp of Syn Gas Compressor and conversion of CO2 Reomval System from GV to aMDEA. In view of these modifications, Waste Heat Boiler has been replaced by new Steam Super-Heater at the outlet of High Temperature Shift Converter, to superheat HP steam to about 350°C, with consequent reduction of the firing in Auxiliary Steam Superheater.

Scheme 3: Following modifications are incorporated in Synthesis section:

A.   Revamp of Synthesis Gas Compressor involving replacement of HP case and LP case barrels by new barrels for increase in efficiency

A.   New Ammonia wash system in Synthesis Gas Compressor 2nd discharge to remove oxygenated compounds from synthesis gas and sending 3rd stage discharge directly to recirculator stage discharge

Scheme : Revamp of Synthesis Gas Compressor involving replacement of HP case and LP case barrels by new barrels for increase in efficiency

Original System:

Syn Gas Compressor consists of two case LP case and HP case with each case having two stages. The first three stages of Syn Gas Compressor is used to compress mixture of make-up gas coming from Methanator and recyle hydrogen coming from Purge Gas Recovery Unit. The fourth stage is used to compress synthesis gas coming from Ammonia Separator of synthesis loop. The drive for Synthesis Gas Compressor is extraction cum condensing turbine using inlet steam as HP steam.

Modified System:

Existing HP case and LP case barrels of Synthesis Gas Compressor has been replaced by new barrels for increasing the efficiency of Synthesis Gas Compressor. With the increased efficiency, steam consumption in turbine drive of Synthesis Gas Compressor has been reduced which results in steam saving.

Scheme: New Ammonia wash system in Synthesis Gas Compressor 2nd discharge to remove oxygenated compounds from synthesis gas and sending 3rd stage discharge directly to recirculator stage discharge

Original System:

Synthesis gas from Methanator was compressed in three stages of Synthesis Gas Compressor with interstage coolers and separators and then sent to upstream of 2nd Ammonia Chiller in syn loop to remove oxygenated compounds (H2O, CO and CO2). These oxygenated compounds are detrimental for the catalyst of Synthesis Converters. In Syn loop, after 2nd Ammonia Chiller, condensed ammonia in the mixture of synthesis gas and make up gas, gets separated in Ammonia Separator. Ammonia produced is sent to Let Down Vessel, from where it is sent to Urea plant for the production of urea.

Uncondensed gas, known as recycle gas, is heated in heat exchangers and then compressed in fourth stage of Synthesis Gas Compressor. The compressed gas is fed to 1st Ammonia Synthesis Converter and 2nd Ammonia Synthesis Converter alongwith Waste Heat Boilers for the synthesis of ammonia and to utilise generated heat to produce HP steam. After Converters and Waste Heat Boilers, the recycle gas is cooled to temperature of around 11°C through series of heat exchangers and then sent to Ammonia Seperator.

Modified System:

In order to increase the energy efficiency of the synthesis loop, a syn gas dehydration system, based on liquid ammonia washing has been installed at Synthesis Gas Compressor second stage discharge. The oxygenated compounds (H2O, CO and CO2) present in Syn Gas are now being separated in Ammonia Wash System. With this modification, Syn Gas Compressor 3rd stage discharge which is free from oxygenated compounds, is being mixed directly with recirculator discharge and fed directly to Hot-Hot Heat Exchanger and then to the 1st Ammonia Synthesis converter. With this modification, power requirement in tubine drive of Synthesis Gas Compressor has reduced due to reduction of load on recirculator stage because of reduced flow of recycle flow.

Scheme 4: Replacement of existing Water Cooler using indirectly cooled DM water as cooling medium for cooling of synthesis gas with new heat exchanger using cooling water as cooling medium
Original System:

In Synthesis loop, indirectly cooled DM water (sweet water) was being used in shell side of Water Cooler (E-1504) to cool synthesis gas from 650C to 400C. Hot DM water from E-1504 was cooled in Plate type sweet water (SW) cooler using cooling water and then the cold DM water was again sent to Water Cooler (E-1504) for syn gas cooling. DM water was then re-circulated using Sweet water circulation pump. Due to higher temperature of DM water, inefficient cooling of synthesis gas in E-1504 was taking place resulting in higher loop pressure.

Modified System:

Sweet Water Cooler System (Water Cooler, Plate type Sweet Water Coolers, Sweet Water Circulation Pump and Sweet Water Accumulator) has been replaced with new Water Cooler using cooling water directly as cooling medium for better cooling of synthesis gas. With this modification, loop pressure reduced resulting in steam saving in Syn Gas Compressor turbine. Also, electricity consumption required in motor drive of Sweet Water Circulation Pump in original system has been eliminated.

Scheme 5: Replacement of existing finned type Combustion Air Preheater with new plate type Combustion Air Preheater
Original System:

In Primary Reformer, feed mixture i.e NG and superheated MP steam is reformed in tubes consisting of Ni based catalyst. For reforming reaction, being an endothermic reaction, the source of heat is provided through side fired NG burners. Primary Reformer consists of radiant section and convection section.

In convection section, heat of flue gas coming from radiant section is recovered in series of coils to heat natural gas, process air, HP steam and combustion air. Existing finned type Combustion Air Preheater was made of carbon steel. The stack temperature remained around 186° C which is considered as wastage of recoverable heat.

Modified System:

Existing finned type combustion air preheater made of carbon steel has been replaced by a new Plate type Combustion Air Preheater. With the installation of new plate type combustion air preheater, air leakages has been reduced to minimum and also there is increase in heat transfer efficiency. Now stack temperature decreased from existing 186° C to 130° C. Due to recovery of heat from flue gases in combustion air, the fuel consumption in primary reformer has also reduced.

Scheme 6: Replacement of existing BFW Pre-heater in synthesis loop with a new BFW Pre-heater of higher surface area.
Original System:

Ammonia synthesis reaction requires high pressure & high temperature and is exothermic in nature. Temperature of synthesis gas at downstream of 2nd Ammonia Synthesis convertor remains about 410°C- 420°C. In order to reduce the temperature, synthesis gas is to be passed through the number of exchangers installed in series in which existing Boiler Feed Water (BFW) Pre-heater is installed at the downstream of 2nd waste heat boiler. Synthesis gas passed through the BFW Preheater and transferred their heat to Boiler Feed Water. Temperature of synthesis gas is reduced by about 70°C.

Modified System:

Original Boiler Feed Water (BFW) Preheater has been replaced with a new Boiler Feed Water (BFW) Preheater of higher surface area in order to recover more heat present in the converter outlet gases from the outlet of 2nd Waste Heat Boiler (E-1501). The installation has also reduced the heat load on water cooler (E-1504) reducing the wastage of heat in Cooling Tower.

Scheme 7: Following schemes have been implemented in Urea Plant:

Replacement of existing CO2 Compressors with new higher efficiency compressors

Installation of VAM in 11 & 21 streams of Urea Plant

Original System:

CO2 gas at 40°C received from Ammonia plant and is cooled to 15°C in CO2 Cooler before being compressed in two streams 11 & 21 Unit of Urea plant through CO2 Compressors. The cooling media for CO2 cooler was chilled water from VAM Units of Power Plant. The compressed CO2 gas is then fed to Urea Reactor for the synthesis of urea. The drive for CO2 Compressor is extraction cum condensing turbine using HP steam as inlet steam.

Modified System:

A separate dedicated Vapour Absorption Machine (VAM) has been installed in Urea-I Plant to generate chilled water required for existing CO2 cooler to be installed at the suction of CO2 Compressor of Urea plant. The chilled water cools inlet CO2 gas of CO2 Compressor from 40°C to 15°C, resulting in saving of steam.

In both 11 & 21 Units of Urea plant, existing CO2 Compressors have been replaced with new CO2 Compressors of higher efficiency. With the increased efficiency, steam consumption in turbine drive of CO2 Gas Compressor has reduced.

Scheme 8: Installation of Ammonia Preheaters in 11 & 21 streams of Urea Plant at upstream of Carbamate Recycle Ejector.
Original System:

Ammonia from Ammonia plant is received in Ammonia Receivers of 11 & 21 streams of Urea plant. In each stream, from Ammonia Receiver, ammonia is pumped by Ammonia Booster Pump and then by Ammonia Feed Pump to feed ammonia to Urea Reactor. After synthesis reaction in Urea Reactor, the solution consisting of urea, carbamate and water is sent to HP Stripper for the recovery and recycling of NH3 and CO2 from carbamate solution.

LP Decomposer off gases along with carbonate solution coming from Distillation Tower, was condensed in LP condenser. Carbonate solution from LP Condenser then sent to Carbonate solution accumulator. Cooling water in tube side of LP Condenser is used as cooling media and heat of condensation is dumped to Cooling Tower.

Modified System:

To utilize the condensation heat of LP decomposer off gases, Ammonia Preheater has been installed in the upstream of existing HP Ejector in ammonia feed line, to pre-heat the ammonia entering the reactor in both streams of Urea plant. The heating media is mixture of vapors coming from the top of LP Decomposer, and the solution coming from Distillation Tower Reflux pumps. With the above modification, energy saving has been achieved by utilizing energy of LP Decomposer off gas which in existing system was dumped to cooling water.

Aonla-II

Scheme 1: Replacement of existing GV solution based CO2 removal section by aMDEA solution based CO2 removal section for less energy requirement.
Original System:

In CO2 removal section of Ammonia-II plant, GV solution (a hot potassium carbonate solution) was used to absorb CO2 from process gas in CO2 Absorber. CO2 rich GV solution was regenerated in two stages i.e. in 1st Regenerator and then in 2nd Regenerator. CO2 gas separated was then sent to Urea plant for the production of urea. The source of regeneration energy was process gas and LP steam. Regenerated GV solution was again sent to CO2 Absorber to absorb CO2 from process gas.

CO2 content in the process gas at the exit of CO2 Absorber: 500 ppm. Regeneration energy required: 830 kcal/NM3.

Modified System:

The GV solution based CO2 Removal section has been replaced by aMDEA solution based CO2 Removal section. A new Bulk Absorber in addition to existing CO2 Absorber is being used to absorb CO2 in aMDEA solution from process gas. CO2 rich aMDEA solution is being regenerated in three stages, firstly in HP Flash Vessel, then in LP Flash Vessel and finally in CO2 Stripper. The source of regeneration energy is only process gas. CO2 separated is being sent to Urea plant for the production of urea and regenerated aMDEA solution again sent to CO2 Absorber to absorb CO2 from process gas.

CO2 content in the process gas at the exit of CO2 Absorber: <= 500 ppm Regeneration energy required: 460 kcal/NM3 With decreased regeneration energy requirement in CO2 Removal section and better CO2 removal in CO2 Absorber, steam to carbon ratio at Primary Reformer inlet has been decreased to 3.0. This has resulted in reduction of front-end pressure drop and also saving of HP steam at turbine drive of Synthesis Gas Compressor.

Scheme 2: Installation of Ammonia Preheaters in 31 & 41 streams of Urea Plant at upstream of Carbamate Recycle Ejector.
Original System:

Ammonia from Ammonia plant is received in Ammonia Receivers of 31 & 41 streams of Urea plant. In each stream, from Ammonia Receiver, ammonia is pumped by Ammonia Booster Pump and then by Ammonia Feed Pump to feed ammonia to Urea Reactor. After synthesis reaction in Urea Reactor, the solution consisting of urea, carbamate and water is sent to HP Stripper for the recovery and recycling of NH3 and CO2 from carbamate solution.

LP Decomposer off gases along with carbonate solution coming from Distillation Tower, was condensed in LP condenser. Carbonate solution from LP Condenser then sent to Carbonate solution accumulator. Cooling water in tube side of LP Condenser is used as cooling media and heat of condensation is dumped to Cooling Tower.

Modified System:

To utilize the condensation heat of LP decomposer off gases, Ammonia Preheater has been installed in the upstream of existing HP Ejector in ammonia feed line, to pre-heat the ammonia entering the reactor in both streams of Urea plant. The heating media is mixture of vapors coming from the top of LP Decomposer, and the solution coming from Distillation Tower Reflux pumps. With the above modification, energy saving has been achieved by utilizing energy of LP Decomposer off gas which in existing system was dumped to cooling water.

Scheme 3: Installation of VAM and CO2 Cooler in Urea-II Plant

Original System:

CO2 gas from Ammonia plant was supplied to Urea-II plant at 1.54 kg/cm2a pressure and 40°C temperature. CO2 gas was then compressed by CO2 compressor to about 151 kg/cm2a pressure and 106°C temperature and being sent to Urea reactor for urea synthesis. The drive for CO2 Compressor is extraction cum condensing turbine using HP steam as inlet steam.

Modified System:

A separate dedicated Vapour Absorption Machine (VAM) and CO2 cooler at the suction of CO2 Compressor have been installed in Urea-II Plant. Chilled water required for CO2 cooler is generated from VAM. The chilled water cools inlet CO2 gas of CO2 Compressor from 40°C to 15°C, resulting in saving of steam.

Power Plant:

Scheme 1: Advance Seal Uprate of Gas Turbine Generator (GTG- I)

Gas Turbine load in power plant was expected to increase after commissioning of energy saving schemes. It was found that leakages from the seals of gas turbine may be reduced so that output of Gas Turbine could be increased to meet the requirement of higher power in the Aonla Complex. Existing seals of Gas Turbine- I has been uprated with advanced seals to improve the performance, efficiency and reliability. The replacement resulted in increased output with lower heat rate.

Scheme 2: Modification in exhaust duct of Gas Turbine Generators, (GTG-I and GTG- II)

After implementation of energy saving project, electrical power demand was expected to increased in complex. During study of flow pattern of flue gases in existing GTG exhaust duct, it was observed that there is margin of saving in pressure drop with some modification in exhaust duct. In order to have better operational flexibility at higher load of Gas Turbines, following modifications have been incorporated in exhaust duct of GTG-I & GTG-II:

a)   Replacement of existing HRSG transition duct segment with modified HRSG aero acoustic transition duct segment

b)   Replacement of existing Splitter Silencer with new Aerodynamically balanced Silencer at new location (in bypass duct at downstream of dampener).

Modified aero acoustic transition duct has helped in eliminating high velocity hot spot and localized flow separation. This has caused reduction in pressure drop in exhaust ducts. Due to the reduction in pressure drop, heat rate of GTG-I and GTG-II has reduced which has resulted in saving of energy.

JOBS UNDERTAKEN TOWARDS USE OF ALTERNATE & RENEWABLE ENERGY AND CONSERVATION OF NATURAL RESOURCES

The status of various jobs undertaken at Aonla Unit towards use of Alternate & Renewable Energy and conservation of Natural Resources, are as under:

Tree Plantation:

Target for year 2017-18 = 5000 nos.

Tree Plantation in year 2017-18 = 6599 nos

Vermi-compost production:

Target for year 2017-18 = 31,850 kg

Vermi-compost produced = 31917 kg

Water consumption per MT of Urea:

Water consumption target for year 2017-18 = less than 5.9 m3/MT of urea

Water consumption achieved = 5.753 m3/MT of urea

Environmental Awareness Programs for employees, contract labours, villagers etc.

Target for year 2017-18 = 400 Nos. participants

Environmental Awareness provided = 432 Nos. participants

Reduction in annual electrical Power Consumption by replacement of conventional electrical devices with energy efficient devices in plant and township:

Target for year 2017-18 = 500 MWh

Achieved in year 2017-18 = 454 MWh

Commissioning of 2.2 MW solar Power Project

Installation of 1500 KW solar power system completed.

756 KW solar power system has been commissioned and commissioning of 250 KW solar power system is under progress.