The use of hydrogen is common in industrial processes that acquire a clean and reliable product, such as the chemical industry, the petrochemical industry and the production of electricity, hydrogen and industrial gasses. A company that specializes in complete hydrogen installations asked Kapp to develop a heat exchanger that they could apply in their products.
The problem was the substance that would run through the heat exchanger: potash hydroxide, a potentially dangerous product that requires extreme measures regarding safety and design. Other demands were little loss of pressure and a compact installation that resists a high operating pressure of 16 bars. The customer also wanted a design that could be mass-produced. A Shell & Tube heat exchanger would be perfect because it is welded and it resists a high operating pressure as well as variations in pressure. But: they need a lot of space and that is just not very handy if you plan a compact installation on a skid.
We opted for a plate & shell heat exchanger because of its smaller size. Besides, the installation resists higher pressures. We chose to use AISI 316 materials. The plates however are thicker then normal. The capacity of the installations is from 12 KW up to 27 KW. The customer uses several models with several capacities. They have been supplied by Vahterus in Finland. The installation doesn’t need specific maintenance. The units will be cleaned using hot water. The liquid that runs through the unit does not contaminate it. Because the complete unit has been welded, the cost of maintenance will remain low. Gaskets and suchlike won’t need to be replaced.
In its current function, the exchanger uses a flow of MDI, which is to be cooled down, in order to heat a flow of PMDI. The resulting regenerative power is 1 Megawatt. We calculated that the exchanger will recoup its investment within 4 months of continuous service, which convinced the customer to choose for Kapp. The customer was very specific about:
- High PED-class
- Vacuum tests
- Non-destructive tests
- Strength calculations
- Welding procedures
- Extra connections for drains