FISH FARMING TECHNOLOGY
FISH FARMING TECHNOLOGY #4 Fit for fish farms - Adsorptech EcoGenTM by Adsorptech
One of the most crucial elements for achieving a successful RAS fish farm financing business case and operation is a cost effective and reliable oxygen supply. Adsorptech Principals have been designing and operating oxygen production equipment for decades. However in 2012 we barely knew how to spell “Aquaculture” let alone understand the farmers oxygen needs. As the size of RAS systems increase, the need for onsite produced oxygen increases because the cost and availability of relatively large amounts of a liquid oxygen (LOX) alternative becomes RAS business case and reality prohibitive.
As a designer of production equipment, it is crucially important to understand the needs of the end use customer – not just in the sense of economics but what else keeps them awake at night. At Jim Flaherty’s, Adsorptech President & CEO, first introduction to aquaculture at the Aquaculture America 2012 tradeshow in Las Vegas, Nevada, considerable time was spent listening to a plethora of technical presentations. Ironically the best understanding came by a chance meeting at one evening’s cocktail hour. While munching on excellent shrimp (RAS farm raised I am sure) and drinking an excellent complementary red wine, two gentlemen joined Jim’s table – a RAS farm design engineer and an insurance agent dedicated to RAS coverages. After typical introductions and pleasantries, Jim asked the designer what was important about oxygen to a RAS complex. The two major responses were 1) total operating cost and 2) reliability. Cost importance is a given. For RAS farms, power is a major operating cost, mostly related to pumping the water. Loss of oxygen results in fish mortality. The reliable supply issue led to the question at what point does mortality come into play. It was identified that down to 50 percent of maximum need, the fish will survive, but not grow. Below 50 percent mortality becomes a certainty. The insurance agent chipped in that if a 50 percent redundancy was available, he would be able to lower the RAS insurance premium costs.
Design second
Since Adsorptech was just then on the cusp of creating a new onsite oxygen production technology, the RAS needs were incorporated into the design philosophy. First and foremost, the product needed to achieve very low power consumption. Second, the product needed to achieve cost effective redundancy for 50 percent of the design capacity even during maintenance periods. An innovative way was needed to achieve this 50 percent redundancy for a lower cost than supplying two half-sized units because as the unit sizes get smaller the unit capital costs get higher. In 2013 Adsorptech created and patented its EcoGenTM Oxygen VPSA Generator. Everyone asks what does EcoGenTM stand for? Take your pick – Economic Generation or Ecological Generation – both apply.
Major EcoGenTM differentiation
Adsorptech’s EcoGenTM Oxygen VPSA has the lowest power consumption than any other source of oxygen in the world. At one barg product delivery pressure, the EcoGenTM requires only 0.22 kw/kg oxygen product and 0.24 kw/kg at three barg delivery pressure. The EcoGenTM has a unique operating capability as well. Because the process incorporates a two-bed system, when one of the front end components, such as the blower, motor, VFD or silencer, is shut down for planned or unplanned maintenance, the EcoGenTM is able to run at 50 percent of its rated capacity simply by hitting a single “button”. The button is an electronic signal either input locally at the EcoGenTM HMI or remotely from any computer with authorised access.
Fit for today, fit for tomorrow
As RAS technology has evolved, many realised that lower water pressures mean better business cases. So several RAS design innovators and oxygen dilution equipment suppliers have come up with lower pressure solutions – below three barg and in some cases below one barg. Onsite oxygen production technologies such as PSA deliver six to seven barg, which was adequate for the traditional cone dissolution equipment. However, the power to pump water to such a high pressure and the fact that oxygen PSA requires at least twice the power of EcoGenTM oxygen VPSA means the higher pressure simply results in a serious and now avoidable penalty.
Low life cycle cost perspective
Because the Adsorptech Principals have operated as well as designed oxygen production equipment for more than two decades, the design philosophy is lowest life cycle cost. 42 | December 2017 - International Aquafeed