The high temperatures and pressures, corrosion and crystallization inherent in the urea manufacturing process can put even the most reliable pressure measurement equipment to the test, quickly rendering it inoperable.
In this article, discover a diaphragm seal that's tough enough to protect gauge pressure, absolute and differential transmitters from the highly aggressive environments encountered in urea fertilizer production.
Organic farming dreamed of chemical-free crops that would preserve our health and our environment. Today, the dream of the 80s is coming up against the reality of the soil: without help, the land is running out of nutrients.
The Food and Agriculture Organization of the United Nations (FAO) estimates that food production will have to increase by +70% to feed the 2.3 billion additional human beings on our planet by 2050.
At the same time, the area of cultivated land continues to shrink. Cultivated farmland used to cover 5 billion hectares worldwide. But every year, more than 3 million hectares are severely degraded.
Today, nearly 5 million hectares of our arable land are lost every year.
The population is expected to reach 9.7 billion by 2030, and more than 11 billion by 2100.
In recent years, this demographic pressure has led the agricultural world to increase the yield of arable land. This is a more environmentally-friendly method.
By comparison, past agricultural practices are responsible for over 80% of global deforestation: every year, 51,600 square kilometers of forest go up in smoke. That's equivalent to the size of Costa Rica!
Add to this the declining demand for biofuels, and the global market for mineral fertilizers is expected to reach 143.34 billion USD by 2028.
Today, the need for mineral fertilizers is exploding on every continent!
Urea production is becoming a critical issue, at a time when global urea production is approaching 200 million tonnes a year, and demand has soared since the beginning of the year.
With the rise in agricultural commodity prices, countries such as Australia and Korea are finding themselves on the brink of the abyss.
And global tension is unlikely to ease before 2023.
Optimizing yield, increasing efficiency and profitability of production units is becoming a major challenge for plant managers faced with an unavoidable compromise to meet exacerbated urea demand: synthesize more product in an attempt to increase production at the risk of compromising plant efficiency and product quality, or maximize urea quality to the detriment of volume and yield.
It's a real challenge for the maintenance manager, who has to anticipate problematic, lengthy and costly plant shutdowns that are nonetheless essential to ensure the longevity and safety of installations, maintain optimum operation of all equipment and limit maintenance periods.
It's also a constantly renewed challenge for the instrumentation manager, who has to adapt to the extreme conditions and dangers inherent in urea production.
The challenge is complicated by the constantly evolving choice of technologies and materials required to avoid breakdowns and forced plant shutdowns.
Improving the reliability of manufacturing processes, avoiding production stoppages and guaranteeing plant safety are particularly difficult in these conditions.
And the people responsible for increasing overall efficiency and keeping plants up and running are under great pressure from the complexity of urea manufacturing processes, which are very aggressive on equipment.
Although urea processing approaches differ from plant to plant, the production process is common to all.
It starts with the high-pressure synthesis of ammonia and carbon dioxide. There are two main reactions:
The residual ammonium carbamate is first separated from the urea-water mixture in a high-pressure extractor, then in a recirculation stage.
The water is then expelled in the evaporation stage to form molten urea. Finally, the molten urea undergoes a granulation process to obtain a final solid urea product of the desired quality.
Every urea production process presents unique safety, reliability and efficiency challenges that compel plant managers to improve the performance of their facilities for a safer, more reliable and more environmentally friendly fertilizer industry. a safer, more reliable and more environmentally-friendly fertilizer industry.
A goal that can only be achieved with innovative, high-performance measuring equipment and instruments, specially designed and manufactured with materials that can withstand corrosive environments and ensure a long service life.
Materials selection is therefore vital at the very design stage of equipment and measuring instruments. Incorrect material selection can lead to catastrophic failures, plant shutdowns and even loss of life.
The materials used for pressure transmitters, as well as the choice of sensor technology, play a very important role in the fertilizer industry, and particularly in the urea industry.
Just like the strippers, scrubbers and reactors in your plants, urea measuring instruments are subject to chemical attack by ammonium carbamate, which causes accelerated degradation of components in contact with this highly corrosive agent.
However, the conventional materials used for the thin diaphragm of a pressure transmitter's measuring cell do not protect against erosion, corrosion and the mechanical stresses inherent in the urea manufacturing process.
By using urea grade 1.4466 stainless steel, existing urea processes can then achieve a higher level of performance, resulting in energy savings and a higher level of safety thanks (for example) to a reduced need for passivation.
However, the measuring cell and electronic components used to manufacture pressure transmitters cannot withstand the high temperatures of the process fluid.
That's why it's essential to use diaphragm seals .
Fuji Electric's pressure transmitters withaustenitic stainless steel urea grade 1.4466 diaphragm seals are, in most cases, the best choice for use under normal urea production process conditions, at pressures up to 26 bar (377 psi) and temperatures up to 180°C (356°F). Above these conditions, the use of zirconium or tantalum diaphragm seals may be necessary for more critical measurement points.
The use of 1.4466 austenitic urea-grade steelincreases the corrosion resistance of pressure transmitter for fertilizer plants, resulting in :
USEFUL LIFE GUARANTEE
MAXIMUM SAFETY
RELIABLE, ROBUST DESIGN
The urea grade steel 1.4466 - 25.22.2 - 310 Mo LN - S31050 - 2RE69 used to manufacture diaphragm seals and diaphragms for Fuji Electric urea pressure transmitters is a fully austenitic stainless steel with very low carbon content and impurities.
Practical experience has confirmed its excellent resistance to urea (ammonium carbamate) corrosion at high pressures and temperatures. It is also highly resistant to inorganic acids.
This steel grade is characterized by :
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