**3.1 Plant description**

262 Modeling and Optimization of Renewable Energy Systems

1992 1994 1996 1998 2000 2002 2004 2006 2008

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

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

year

1992 1994 1996 1998 2000 2002 2004 2006 2008

year

0

0

50

100

150

Production,kton HNO3

200

250

300

350

50

100

150

Plant capacity, kton HNO3

200

250

300

350

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

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 eliminated.

Fig. 4. Nitric acid plant in ANWIL SA

Modernization and Intensification of Nitric Acid Plants 265

Fig. 5. Condensate separator from tail gases

#### **3.2 Plant modernization stages**

No significant modernization works were performed in 1980-2000 due to a poor economic trend. The main objective was to provide continuous operation of the plant which contributed to decrease of the number of plant stays from 25 in 1980 to 7 in 2000.

Actions aiming at modernization and intensification of the plant have been undertaken since 2000. Some worn out equipment was replaced and due to actions undertaken exchange of one of the most important apparatus that is a high pressure tail gases heater E2211 became unnecessary. The results of analysis11,12) of operation conditions of this apparatus indicated the necessity of application of condensate drops separation from tail gases after absorption column. Furthermore, periodical controls of wall thickens of this apparatus were performed, as well as maintenance of thinned or damaged tubes by placing rolled steel tubes 2RE10 inside and washing process optimization of nitrous gases compressor and continual controls of dehydrating nozzles permeability.

The preparation of mass and heat balance by Fertilizers Research Institute for the load of 1100 t HNO3/d (122%) and specification of the changes to be introduced into loop, limiting production capacity, were the next stages of modernization process. A number of actions were undertaken by ANWIL SA based on the results of above mentioned works and their own observations, the realization of which was the condition for the increase of the production capacity. They included mainly:


#### **3.3 Results of plant modernization**

The solutions applied concerning failure frequency of nitrous gases heater E2211 resulted in operation time prolonging of this apparatus. The amount of condensate introduced earlier with tail gases to the separator was significantly reduced due to separator built-up Fig. 5. The modernization of the other technologically important apparatus –condenser E2209 consisted of a different distribution of cooling water, its degassing system in the upper bottom of the sieve and different method of tube fixing in the sieve bottom. A significant reduction of condenser corrosivity is envisaged to be the result of this modernization.

The application of selective NOx reduction and the modernization of boiler system and whitening column as well as the increase of NH3-air relation allowed for an increased plant load due to decreased pressure in absorption loop and directing larger amount of air for ammonia oxidation process. Boiler system modernization consisted mainly of the use of circulation pump of a higher efficiency and the change of circulation tube system. During whitening column modernization hydraulics of liquids and gases flow was improved due to tray and weir modernization, which allowed for the 40% reduction of the air necessary for nitric acid whitening.

No significant modernization works were performed in 1980-2000 due to a poor economic trend. The main objective was to provide continuous operation of the plant which

Actions aiming at modernization and intensification of the plant have been undertaken since 2000. Some worn out equipment was replaced and due to actions undertaken exchange of one of the most important apparatus that is a high pressure tail gases heater E2211 became unnecessary. The results of analysis11,12) of operation conditions of this apparatus indicated the necessity of application of condensate drops separation from tail gases after absorption column. Furthermore, periodical controls of wall thickens of this apparatus were performed, as well as maintenance of thinned or damaged tubes by placing rolled steel tubes 2RE10 inside and washing process optimization of nitrous gases

The preparation of mass and heat balance by Fertilizers Research Institute for the load of 1100 t HNO3/d (122%) and specification of the changes to be introduced into loop, limiting production capacity, were the next stages of modernization process. A number of actions were undertaken by ANWIL SA based on the results of above mentioned works and their own observations, the realization of which was the condition for the increase of the


The solutions applied concerning failure frequency of nitrous gases heater E2211 resulted in operation time prolonging of this apparatus. The amount of condensate introduced earlier with tail gases to the separator was significantly reduced due to separator built-up Fig. 5. The modernization of the other technologically important apparatus –condenser E2209 consisted of a different distribution of cooling water, its degassing system in the upper bottom of the sieve and different method of tube fixing in the sieve bottom. A significant reduction of condenser corrosivity is envisaged to be the result of this modernization.

The application of selective NOx reduction and the modernization of boiler system and whitening column as well as the increase of NH3-air relation allowed for an increased plant load due to decreased pressure in absorption loop and directing larger amount of air for ammonia oxidation process. Boiler system modernization consisted mainly of the use of circulation pump of a higher efficiency and the change of circulation tube system. During whitening column modernization hydraulics of liquids and gases flow was improved due to tray and weir modernization, which allowed for the 40% reduction of the air necessary for

modernization of feeding system and hydrogen and NH3-air distribution16).

contributed to decrease of the number of plant stays from 25 in 1980 to 7 in 2000.

compressor and continual controls of dehydrating nozzles permeability.


**3.2 Plant modernization stages** 

production capacity. They included mainly: - the application of selective NOx reduction, - the increase of turbine sets energy efficiency,



**3.3 Results of plant modernization** 

nitric acid whitening.

Fig. 5. Condensate separator from tail gases

Modernization and Intensification of Nitric Acid Plants 267

1999 2001 2003 2005 2007 2009

\*

year

The modernization of ammonia oxidation reactors consisted mainly of built-up of special catalytic baskets, which were delivered by Johnson Matthey. This allowed for the installation of the catalyst for a high temperature nitrous oxide decomposition within JI project. The catalyst developed by Fertilizers Research Institute was applied in one of the plant trains. The modernization of NH3-air and hydrogen distribution made the plant safer during start-up and protected catalytic gauzes (of PtRh-Pd alloy) against contamination and

Nitric acid plants modernization performed by AZOTY Tarnów and ANWIL SA Włocławek increased stability and reliability of these plants and improved their energy efficiency. The possibility of significant intensification of production capacity and exploitation level was achieved. A nominal production capacity was increased up to 130% in AZOTY Tarnów and

[2] W. Janicki, A. Laska, K. Bronikowski, K. Kozłowski, J. Nieścioruk, M. Wilk, *Projekt* 

[3] L. Gniadek, A. Kruszewski, R. Świtalski, *Pr. nauk. Inst. Technol. Nieorg. PWr nr 39, Seria:* 

Fig. 7. Generation increase in steam carried away to the plant system

[1] M. Wilk, K. Kozłowski, J. Nieścioruk, *Przem. Chem.,* 1988, t. 67, 10, 464.

[4] K. Kozłowski, *Pr. nauk. Inst. Technol. Nieorg. PWr nr 39, Seria: Konf. nr 21*, 11.

[6] M. Wilk, J. Nieścioruk, *Sprawozdanie INS*, nr 2819, Puławy, 2003.

0

damage.

**4. Summary** 

**5. References** 

up to 125% in ANWIL SA.

*procesowy*, Gliwice, 1985.

[5] M. Wilk, J. Nieścioruk, *Projekt INS*, Puławy, 1998.

*Konf. nr 21*, 3.

5

10

Steam production, t/h

15

20

25

After additional modernization of turbine set rotors (adjusted shapes of blades and the application of a different method of fixing blades to the rotor disks) the increase of the plant load up to 122% and even up to 125% temporarily became possible with a co-existent energy efficiency improvement. The results of modernization discussed here are presented on Fig. 6 and 7.

Fig. 6. Annual production of nitric acid in ANWIL SA

After additional modernization of turbine set rotors (adjusted shapes of blades and the application of a different method of fixing blades to the rotor disks) the increase of the plant load up to 122% and even up to 125% temporarily became possible with a co-existent energy efficiency improvement. The results of modernization discussed here are presented on Fig. 6

1971 1974 1977 1980 1983 1986 1989 1992 1995 1998 2001 2004 2007

year

and 7.

0

Fig. 6. Annual production of nitric acid in ANWIL SA

100

200

300

400

Production, kton HNO3

500

600

700

800

Fig. 7. Generation increase in steam carried away to the plant system

The modernization of ammonia oxidation reactors consisted mainly of built-up of special catalytic baskets, which were delivered by Johnson Matthey. This allowed for the installation of the catalyst for a high temperature nitrous oxide decomposition within JI project. The catalyst developed by Fertilizers Research Institute was applied in one of the plant trains. The modernization of NH3-air and hydrogen distribution made the plant safer during start-up and protected catalytic gauzes (of PtRh-Pd alloy) against contamination and damage.

#### **4. Summary**

Nitric acid plants modernization performed by AZOTY Tarnów and ANWIL SA Włocławek increased stability and reliability of these plants and improved their energy efficiency. The possibility of significant intensification of production capacity and exploitation level was achieved. A nominal production capacity was increased up to 130% in AZOTY Tarnów and up to 125% in ANWIL SA.

## **5. References**


**12** 

*1Lebanon 2,3Canada* 

**Optimal Design of an Hybrid Wind-Diesel** 

**for Canadian Remote Areas** 

*1Lebanese University, Faculty of Engineering, Beirut, 2LREE, University of Quebec in Chicoutimi, Chicoutimi, 3LREE, Quebec University in Rimouski, Rimouski,* 

Younes Rafic1, Basbous Tammam2 and Ilinca Adrian3

**System with Compressed Air Energy Storage** 

Most of the remote and isolated communities or technical installations (communication relays, meteorological systems, tourist facilities, farms, etc.) which are not connected to national electric distribution grids rely on Diesel engines to generate electricity [1]. Dieselgenerated electricity is more expensive in itself than large electric production plants (gas, hydro, nuclear, wind) and, on top of that, should be added the transport and environmental

In Canada, approximately 200,000 people live in more than 300 remote communities (Yukon, TNO, Nunavut, islands) and are using Diesel-generated electricity, responsible for the emission of 1.2 million tons of greenhouse gases (GHG) annually [2]. In Quebec province, there are over 14,000 subscribers distributed in about forty communities not connected to the main grid. Each community constitutes an autonomous network that uses Diesel generators. In Quebec, the total production of Diesel power generating units is approximately 300 GWh per year. In the mean time, the exploitation of the Diesel generators is extremely expensive due to the oil price increase and transportation costs. Indeed, as the fuel should be delivered to remote locations, some of them reachable only during summer periods by barge, the cost of electricity produced by Diesel generators reached in 2007 more than 50 cent/kWh in some communities, while the price for selling the electricity is established, as in the rest of

The deficit is spread among all Quebec population as the total consumption of the autonomous grids is far from being negligible. In 2004, the autonomous networks represented 144 MW of installed power, and the consumption was established at 300 GWh. Hydro-Quebec, the provincial utility, estimated at approximately 133 millions CAD\$ the annual loss, resulting from the difference between the Diesel electricity production cost and

**1. Introduction** 

cost associated with this type of energy.

Quebec, at approximately 6 cent/kWh [3].

the uniform selling price of electricity [3].

**1.1 Context** 

