Metallic phosphoric acid heaters in place of graphite block heaters Vincent PERROT1 SYMPHOS 2013 in AGADIR Morocco

Summary Vincent PERROT2  Requested heater in 54% Phosphoric acid concentration  Actual Situation  SANICRO 28 Metallic Heater  Graphite blocks heaters replaced by metallic heaters  Typical operating conditions  Financial cost  Conclusion

Requested heater in 54% phosphoric acid concentration Vincent PERROT3 Heater Vacuum Evaporator Steam P 2 O % P 2 O 5 54%

Actual Situation Old units use graphite block heaters and it has shown that blocks : are easily plugged break, crack are involved in production shutdown have an average lifetime of 2-3 years are involved in the very high and unreasonable maintenance costs Vincent PERROT4 Breaks

Actual Situation So, the more recent units have evolved, and now are using graphite tubular heaters. Unfortunately, these heaters cannot solve all the block heaters problems : Graphite tubes stay very brittle and remain under the threat of a tube which can break, stopping the production. Vincent PERROT5

Actual Situation Conclusion : Graphite heaters, despite their evolution, are far away to give a full satisfaction. If units are more secure with tubular graphite heaters, it stay under the threat of a tube which can break, stopping the production. And, older units using graphite block heaters stay extremely expensive in terms of maintenance costs. Vincent PERROT6

Why tubular graphite heaters haven’t replace graphite block heaters ? -Because different design parameters of graphite block heaters cannot be transferred to the tubular graphite heaters, important design characteristics wouldn’t be respected. -The change cannot be done without heavy plant modifications. -Without these heavy modifications, the power of a tubular graphite heater which can be put in place of a block heater will be much more lower. Vincent PERROT7

However, there is another solution now well known and improved in a lot of Phosphoric acid plant all over the world. The SANICRO 28 metallic heater Vincent PERROT8

SANICRO 28 Metallic Heaters The SANICRO 28 stainless steel has been developed for phosphoric acid services. Metallic heaters in SANICRO 28 are especially adapted for 54% phosphoric acid concentration. There is a lot of advantages : Excellent robustness of heaters Tubes cannot break 10 years service life minimum Extremely low maintenance costs No production shutdown All advantages of a metallic solution … Vincent PERROT9

SANICRO 28 Metallic Heaters But, there is another advantage, If you haven’t forgotten the slide 7, you remember that the old units are using graphite block heaters which are extremely expensive in maintenance costs and which cannot be replaced by tubular graphite heaters. A large range of tube diameters can be used in the metallic heaters and with the correct parameters taken from our know how, we can design a metallic heater in the place of a graphite heater. METALLIC TUBULAR HEATERS CAN REPLACE GRAPHITE BLOCK HEATERS WITHOUT HEAVY PLANT MODIFICATION. Vincent PERROT10

Graphite block heaters replaced by metallic heaters The same heating power The same process pipes The same recirculating pump The same support structure Only the steam piping needs to be adapted Vincent PERROT11 With the SANICRO 28 metallic heaters, you will keep in your plant :

Typical operating conditions Graphite heaters Metallic heaters P2O5 pressure 2 to 3 bara 2 to 3 bara P2O5 temperatures 76 to 84°C 76 to 84°C Steam pressure 2,5 to 5 bara2 to 2,5 bara Steam temperatures 130 to 150°C120 to 128°C Note : the lower steam temperature for the metallic solution is easily compensated by an extra exchange surface. Vincent PERROT12

Typical operating conditions Regular cycles of cleaning for metallic heaters are the same than graphite block heaters. - Make a cleaning as often as possible by recirculation of industrial water or sea water. - 3 or 4 times per year, a mechanical and high pressure cleaning of the bundle. The goal of the cleaning is to remove deposit to keep the thermal exchange and avoid the corrosion under deposit. Vincent PERROT13

Financial cost The cost of a metallic heater is approximately the same than the cost of a graphite heater. But, The lifetime of the metallic heater is much more longer than the lifetime of the graphite heater. The maintenance costs of the metallic heater are insignificant. The maintenance costs of the graphite blocks are unreasonable. The purchase budget of the metallic heater can easily be taken on the budget of the block spare parts. Vincent PERROT14

Conclusion SANICRO 28 metallic heaters are the solution to : -Stop the production shutdown of the phosphoric plants. -Decrease the maintenance costs of the phosphoric plants. -Increase the production and the profit of the phosphoric plants. Vincent PERROT15