Improvements to Lab-Scale Multiple Effect Distillation Unit

Jose Pena

CHME 498

5/9/2016

Improvements to Lab-Scale Multiple Effect Distillation Unit

Previously from last semester my role to this experiment was to support and troubleshoot the MED prototype. We did a few test runs, but after testing the distilled water it had a high percentage of iron. We discovered the cast iron steam traps were the reason why the distilled water contained iron. After this discovery we took the MED apart for cleaning and ionized it. While waiting for the MED to be ionized and shipped back to us, we look into getting a heat exchanger and a circulation heater to preheat the brackish water more efficiently. By preheating the brackish water more efficiently, we will obtain a higher yield of distilled water. Then, we contacted multiple companies to obtain price quotes on the heat exchanger and the circulation heater.

This semester, after ordering the heat exchanger and the water heater Michael and I made an excel spreadsheet of a list of parts for the MED unit. The part list had the item, a description, quantity, part number, individual cost of each item, and the total cost for the quantity of that item. We had to make sure we got parts to connect the heat exchanger and the water heater to the MED unit. We looked into getting parts connecting the heat exchanger to one of the effects, the condenser connecting to the heat exchanger, the heat exchanger connecting to the tap water tank, tap water tank to a pump, also making sure we have the proper valves and flowmeters. We also had to look for thermocouples, an aluminum bar to make baffles. After ordering all the parts from McMaster we later discovered we were missing parts and we had extra parts that wasn’t needed. So we created another list of the missing parts then place another order. Once all the parts were shipped to us we then returned any extra parts back to McMaster. Then Charlie’s group got together and worked on assembling the MED.

Since the MED is still being assembled, we had an ASPEN simulation projectto work on and it was to design an interface to produce fresh water using biomass waste. We came across multiple errors and warnings in the simulation. After fixing flow rates and fixing mass balances we were clarify the errors within the simulation but we kept getting a warning on one of the heat exchangers. With experience from my CHME 455L, chemical plant simulation, also with the help of John Schutte, we were able to fix the warning by making sure the right property method was selected. The overall property method in the simulation was PENGROB, for each individual blocks we had to select the property method since we were having flue gas and water within the system. We needed to choose Peng Robinson for the blocks which were flue gas, and STEAMNBS for the blocks which are water wither feed or tap water. In order to properly finish the ASPEN simulation, we need to look for a steam ejector that is available off the shelf and get the equipment specification sheet. Getting the requirements for the ejector will help with the simulation that way we can input the proper value for the suction pressure on the nozzle within the simulation.