Differences between titanium coolers and graphite coolers
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I am working on a graduation project related to the process design for chlor-alkali chemical plants. In the first step of chlorine dehumidification, I’m not sure whether to use a titanium cooler or a graphite cooler. I would appreciate some advice from those with more experience; thank you! !
I don’t know what specific operating conditions you have?
Graphite heat exchangers have better corrosion resistance, but poorer impact resistance; the corrosion caused by wet chlorine is quite severe. If the impact is not too strong, it is better to choose a graphite heat exchanger. If the impact is severe, titanium is the only option.
Free chlorine is very deadly to graphite equipment; I’m not quite sure about the situation with titanium
I’ve learned it! Could it be more detailed!
Graphite heat exchangers can withstand high corrosion. Graphite itself also has good thermal conductivity. Energy cannot be input; heat always flows from higher to lower temperatures. But the heat exchange tubes used must be relatively thick. Titanium heat exchangers are likely not as corrosion-resistant as graphite. Hydrochloric acid should be incompatible, after all, graphite heat exchangers can withstand high corrosion. Graphite itself also has good thermal conductivity. Energy cannot be input; heat always flows from higher to lower temperatures. But the heat exchange tubes used must be relatively thick. Graphite is prone to brittle fracture and has low bending and tensile strength, so it can only be used at low pressures. Its operating pressure is generally only 0.3 to 0.5 MPa. Titanium heat exchangers are likely not as corrosion-resistant as graphite. However, work pressure can increase HF and fluoride levels. Hydrogen fluoride gas reacts with titanium when heated to form TiF4; the reaction equation is (1) ； Anhydrous liquid hydrogen fluoride can form a dense titanium tetrafluoride film on the surface of titanium, preventing HF from penetrating into the interior of the titanium. Hydrofluoric acid is the strongest solvent for titanium. Even hydrofluoric acid at a concentration of 1% can react violently with titanium, as shown in Equation (2) ； Anhydrous fluorides and their aqueous solutions do not react with titanium at low temperatures; only fluorides in molten state at high temperatures react significantly with titanium. Ti + 4HF = TiF4 + 2H2 + 135.0 kcal (1) 2Ti + 6HF = 2TiF3 + 3H2 (2) HCl and chlorides Hydrogen chloride gas can corrode titanium; dry hydrogen chloride reacts with titanium at temperatures above 300°C to form TiCl4, as shown in equation (3) ； concentration
What medium was used for the heat exchanger during your design? Was it wet chlorine and circulating water? If it is wet chlorine, circulating water can be used
What medium was used for the heat exchanger during your design? Was it wet chlorine and circulating water? If it is wet chlorine, circulating water can be used
The wet chlorine gas heat exchangers used in the chlor-alkali industry are all made of titanium; we have the necessary drawings available, and we have manufactured many such units for this industry
Graphite material won’t work; silicon carbide material can be used instead