Modernization and construction of nitric acid production units
Modernization of large-scale non-concentrated nitric acid production units AK-72
The proposed modernization affects the main stages of the production process and includes the following:
- Shifting the unit to low- temperature (280÷340°С) selective catalytic reduction system;
- Nitrous gas heat recovery to preheat the off gases before DeNOx reactor;
- Heating off gases in the universal gas turbine combustion chamber before gas turbine unit;
- Shifting gas turbine unit to low temperature conditions (550÷600°С);
- Removing small scale high temperature off gases heater and tail gas waist heat boiler.
PFD for modernized non-concentrated nitric acid production plant
|РCО – DeNOx reactor||Э/дв – electric motor|
|ПВГ-1,2 – off-gases heater||КСТ – gas turbine combustion chamber|
|ВКД – air compressor||ГТТ-12 – gas turbine unit|
|ВОХ – air cooler|
NIIK’s services for modernization of large- scale nitric acid unit (AK-72):
- Increase of NA production by 4-8 TPH;
- Reduction of natural gas consumption by 30-45 m3/t;
- Minimization of non-recoverable palladium of the catalyst;
- Reduction of steam production for the plant needs to 0,1Gcal/t;
- Reduction of start-up time to 4-5 hours;
- Increase of service life and time between repairs of gas- turbine.
The modernization of the existing AK- 72M unit was carried out for Minudobreniya Company (Rossosh, Russian Federation) in 2014.
The nitric acid production capacity was increased by 20%, natural gas consumption was reduced by 50%, steam production by 15% as compared to the AK-72M design values.
MODERNIZATION OF THE EXISTING NON- CONCENTRATED NITRICACID PRODUCTION UNIT UKL-7
The suggested modernization of the existing nitric acid production unit UKL-7 results in:
- Increased nameplate capacity;
- Decreased air consumption per ton of acid;
- Reduced feedstock and energy consumption;
- Improved ecological performance of nitric acid production.
Main technical solutions on modernization of the existing UKL-7 units:
- Modernization of contact reactor using platinum gauzes of increased diameter (up to 1920 mm) and a new design of catalytic gauzes supporting system without bar screen and arch bearing;
- Modernization of absorption column internal devices increasing throughput capacity;
- Modernization of tail gases preheaters reducing pressure drop and preventing corrosion damage;
- Modernization of tail gases waist heat boiler at the line of treated tail gases for heat transfer efficiency increasing;
- DeNOx reactor modernization for installation of modular and granular aluminium - vanadium catalyst;
- Modernization of the universal off gas combustion chamber optimizing environmental performance.
PFD for modernized non–concentrated nitric acid production unit UKL- 7
|КА – contact reactor||АК – absorption column|
|КУН – LP waste- heat boiler||ПК – blowdown column|
|ПВз – air heater||РCО –DeNOx reactor|
|ПХГ-1,2– tail gas preheater||ЭК – tail gas waist heat boiler|
|ХК-1,2 – cooler condensers||ГТТ-3М – gas turbine unit|
NIIK’ s services for revamps of existing NA units (UKL-7)
- Increase of NA production by 1,5-2,5 TPH;
- Reduction of natural gas consumption by 20-30 m3/t;
- Reduction of power consumption;
- Increase of steam production for the plant needs
NITRIC ACID PRODUCTION UNITS UKL-7-76М WITH CAPACITY 130 000 TPY
The basis of nitric acid production reaction is catalytic oxidizing of ammonium by atmospheric oxygen and absorption of nitrogen oxides at absolute pressure 0,73 МPа.
New technical solutions:
- Contact reactor with the use of platinoid gauzes of increased diameter (up to 2700 mm) and their fixing outside high temperature area;
- High performance gas turbine unit with a compressor;
- Modern automated control&management system based on microprocessor technology and instrumentation for all gas turbine / UKL7-76М modes of operation;
- Combination of universal combustion chamber with gas turbine unit and high temperature coated exhaust duct removal;
- New instrumentation for off gases recuperative heating stage and DeNOx reactor.
The gas turbine unit is characterized by reduced metal consumption and expanded services hours.
Nitric unit production unit UKL -7-76М technical performance
|1||HNO3 monohydrate output||TPH||16,0|
|2||Natural gas consumption||m3/t||75.0|
|4||Steam production for the plant needs Р 1,6 МPа||Gkal/t||1,25|
|6||Cooling water consumption||m3/t||130|
PFD for non concentrated nitric acid production unit UKL-7-76M (capacity 130 000 TPY HNO3 monohydrate)
|КА – contact reactor||ПК – blowdown column|
|КУН– LP waste- heat boiler||РCО – DeNOx reactor|
|ПХГ-1,2– tail gas preheater||КУГ – recovery boiler|
|ХК-1,2 – cooler condensers||ЭК – tail gas waist heat boiler|
|АК – absorption column||ГТКТ-4 – turbo compressor unit|