Phoenix Systems, Inc.
                                        Leaders in Hydrochloric & Sulfuric Acid Recovery

Acid Recovery Heat Exchangers

Does you acid recovery system require frequent hotcycles?

We have upgraded over a dozen older systems and found that over time the PVDF coils become brittle and are subject to frequent breakage.  We have also found that they are permeable.  This is the source of the embrittlement.  You may have noticed that your heat exchanger coils have changed color over the years.  The darkened color is indicative of the fluid (acid) penetrating the surface of the coil.  If you took a cut-away of the coil and looked through an electron microscope, it would look like there were small tree roots growing into the coil.  The “root matrix” that you would be looking at is actually ferrous sulfate.  When you run your system, this root matrix provides an already glazed surface that allows very fast formation of additional ferrous sulfate crystals, causing rapid crystal bridging, requiring progressively more frequent hot cycles.

When your acid recovery system was purchased, PVDF immersion coils were most likely the best exchangers available. Since that time, highly conductive, “ non stick” fluoropolymer coils have gained favor for a number of reasons:  

• FEP or PFA fluoropolymers combined with a proprietary thermal formulation makes a highly conductive heat exchange  compound with conductive qualities more than three times that of PVDF.

• Because the efficiency of the conductive tubing is so high, fewer heat exchangers are required to meet your cooling demand.  Acid recovery system mixing efficiency is enhanced because there is less obstruction of process flow, and more violent agitation of acid across the surface of the heat exchanger coil.  

• The conductive tubing heat exchanger coils that we are specifying are built with wide spacing between coils.  This wide tube spacing promotes enhanced flow and minimizes the possibility of “crystal bridging”.  When your PVDF coils “bridge”, the flow-through qualities are eliminated and for lack of a better description, the exchanger becomes “a wall” where additional crystals grow quickly.

• Teflon® is a “non stick” material.  Because of this, we have had galvanizers not need to “hot cycle” for over six weeks.  And then, only because they thought it might be a good idea.

Acid Recovery Heat Exchanger Quotation

In order to provide you a quotation for replacement heat exchangers, we will need you to provide some information regarding your current acid recovery system.  Please fill out the following form and we will respond to you promptly.