**2. Nitric acid plant 0.5/1.5 MPa, 700 T HNO3/d in AZOTY Tarnów**

#### **2.1 Plant description**

Process design of nitric acid plant of a nominal production capacity – 700 t HNO3/d for Zakłady Azotowe SA in Tarnów-Mościce was prepared by Fertilizers Research Institute and Prosynchem in Gliwice in 19851). The pressure applied that is 0.5 MPa in ammonia oxidation unit and 1.5 MPa in absorption unit provided energy self-sufficiency of this plant and, NOx content in outlet gases below 200 ppm and allowed for the nitric acid production with the concentration of 65% by weight.

The plant called Dual Pressure Nitric Acid Plant, presented on Fig. 1 was started in 1992. During Start-up a number of changes were introduced3,4) which improved its operation

Paweł Sławiński3, Marek Inger1 and Jan Nieścioruk1

<sup>\*</sup> Andrzej Kruszewski2, Marcin Potempa2, Romuald Jancewicz3, Jacek Mendelewski3,

*<sup>1</sup>Instytut Nawozów Sztucznych, Puławy, Poland 2AZOTY Tarnów, Poland* 

*<sup>3</sup>ANWIL SA, Włocławek, Poland* 

Modernization and Intensification of Nitric Acid Plants 261

During the second stage of modernization, works aiming at gradual intensification of the plant (increase of plant capacity) by removal of bottlenecks and further improvement of stability and reliability were performed. More actions than in the first stage were





Due to works performed in the first stage the possibility of nitric acid production on design level with a simultaneous energy consumption improvement was obtained and the number

During the second stage mass and heat balances for the load of 900 and 950 t HNO3/d were prepared within engineering analysis and operation parameters of particular plant units at the above mentioned loads were specified. This analysis was possible with modernization




Research on optimization – the adjustment of catalytic packages for increasing technical nitric acid production in the following platinum campaign was conducted during works

As the result of modernization discussed above daily production capacity of the plant and the level of its exploitation were increased, as presented on Fig. 2 and 3. Moreover, modernization and strengthening of catalytic baskets were performed, which allowed for

which improved its operation and limited corrosion of tail gases heater E14.

built-up of the catalyst for a high temperature N2O decomposition within JI project.

condenser E10, by the change of buffles and the change of tube pack6), - Improvement of mist elimination efficiency and vortex breaker in separator V87),


undertaken to achieve this objective including:

containing operation conditions at this load,

works performed by AZOTY Tarnów. Some of them include:


enabled us to direct additional air to ammonia oxidation unit,

operation at high load,

**2.3 Results of plant modernization** 

turbine condenser,

of plant stays was limited.

was also improved,

over plant intensification.

efficiency and made it safer both for staff and environment. No significant technological errors were found with guarantee parameters and production capacity confirmed during Start-up.

Fig. 1. Nitric acid plant in AZOTY Tarnów

#### **2.2 Plant modernization stages**

The first modernization stage included actions aimed at improvement of plant stability and reliability with a nominal load as well as optimization of heat use. The below mentioned actions were undertaken to achieve these goals:


efficiency and made it safer both for staff and environment. No significant technological errors were found with guarantee parameters and production capacity confirmed during Start-up.

The first modernization stage included actions aimed at improvement of plant stability and reliability with a nominal load as well as optimization of heat use. The below mentioned


Fig. 1. Nitric acid plant in AZOTY Tarnów

actions were undertaken to achieve these goals:




**2.2 Plant modernization stages** 

During the second stage of modernization, works aiming at gradual intensification of the plant (increase of plant capacity) by removal of bottlenecks and further improvement of stability and reliability were performed. More actions than in the first stage were undertaken to achieve this objective including:


#### **2.3 Results of plant modernization**

Due to works performed in the first stage the possibility of nitric acid production on design level with a simultaneous energy consumption improvement was obtained and the number of plant stays was limited.

During the second stage mass and heat balances for the load of 900 and 950 t HNO3/d were prepared within engineering analysis and operation parameters of particular plant units at the above mentioned loads were specified. This analysis was possible with modernization works performed by AZOTY Tarnów. Some of them include:


Research on optimization – the adjustment of catalytic packages for increasing technical nitric acid production in the following platinum campaign was conducted during works over plant intensification.

As the result of modernization discussed above daily production capacity of the plant and the level of its exploitation were increased, as presented on Fig. 2 and 3. Moreover, modernization and strengthening of catalytic baskets were performed, which allowed for built-up of the catalyst for a high temperature N2O decomposition within JI project.

Modernization and Intensification of Nitric Acid Plants 263

Nitric acid plant in ANWIL SA was built according to the project of French company Societe Chimique de la Grande Paroisse in 1968. It consists of two trains of a nominal value of 900 t HNO3/d each. In the 70's it was the first dual pressure plant in Poland. The solutions applied provided energy self-sufficiency of the plant but with the NOx content in tail gases

The plant presented on Fig. 4 was started in 1971-1972. During start-up in the 70's nominal production capacity was obtained and the most important exploitation problems were

**3. Nitric acid plant 0.35/0.9 Mpa, 900 t HNO3/d, ANWIL SA in Włocławek** 

of 400 ppm and NHO3 concentration in solution of 56.5% by weight.

**3.1 Plant description** 

Fig. 4. Nitric acid plant in ANWIL SA

eliminated.

Fig. 2. A change of annual capacity as a result of modernization

Fig. 3. Annual production of nitric acid in AZOTY Tarnów
