Techcross addresses problems with its ballast water treatment system

For any manufacturer, an incident in which an item of its equipment fails in use is a worry. When that failure causes an explosion, there are the additional concerns over crew safety, as well as the technical and operational factors.

South Korean Ballast water system maker Techcross had to deal with two explosions on its ElectroCleen System (ECS) during 2013 and is keen that the industry should benefit from its experience.

It has good reason to be frank and open about what went wrong: in a growing and competitive market in this still relatively new field, no company can afford to allow rumours to spread, especially when its product is one of the leading ballast water treatment systems (BWTS) currently available in the market, as Techcross’s deputy general manager Bill Yoon described it to Ballast Water Treatment Technology.

So it continues to openly share about these two unfortunate incidents at conferences all over the world, through communications to customers, presentations at conferences and providing information to this issue of BWTT. “Techcross believes that with very little industry-wide operational experiences, many more accidents are possible with new equipment onboard vessels, and with crew having little or no prior experience with BWTS,” Mr Yoon said.

ECS is a full flow direct electrolysis system with no need of a fine mesh filter. It is a modular system at the heart of which is an electro chamber unit (ECU), where electrolysis is used to kill any organisms in the ballast water that passes through it. More than 500 Techcross systems have been contracted and, at the time of writing in February, just under 300 systems had been delivered.

But only a few vessels are operating their installed BWTS on a regular basis – an experience common across the industry. As a result, reliable data and information from operational feedback is minimal, said Mr Yoon, and its feedback includes these two incidents, one in April and one in June, each prompting Techcross to issue a technical notification. The second asked operators to cease all operations of their ECS installations until all necessary safety modifications and upgrades were completed.

Both incidents resulted in the main ECU breaking apart at the weakest welding points due to overpressure of water vapour and gases caused by continuous supply of power with the isolation valves shut inadvertently. The first pressure explosion occurred on a container vessel when the critical upper limit of the ECU design pressure was exceeded after a period of 11 days of low power being supplied to an ECU that had no water flowing through it, due to a malfunctioning magnetic contact.

The second incident occurred on a bulk carrier a couple of months later due to operator negligence. In this case, the ECS was turned on with full power flowing to the ECU during deballasting in emergency manual mode with the manual isolation valves shut in the engineroom. Mr Yoon pointed out that ECS has a one-time ballasting operating system and should not be electrolysing water during deballasting. However, due to lack of training and/or operator negligence, the system was turned on with power being supplied to an ECU during deballasting – when it has no water flowing through it – in emergency manual mode. It exploded in just 30 minutes.

It is important to note that both incidents occurred during manual or emergency manual modes. In its automatic mode, there are sensors, alarms and shut-down functions in place to prevent such occurrences. In manual and emergency manual modes, all these functions were overridden. This was a design failure, Mr Yoon said, which Techcross has acknowledged and now fully rectified with upgrades and modifications to both software and hardware. “Techcross never imagined that the system would be turned on during manual or emergency manual mode – overriding all sensors and alarms – with the isolation valves shut so that the internal pressure would be allowed to increase to a critical level causing the electrolysis system to break apart,” he said, and offered this analogy: “although it is common sense not to sleep and drive at the same time, many accidents do happen for this exact reason. This was a very important lesson for Techcross.”

Techcross was fortunate that no one was injured in either incident and has fully accepted responsibility by covering all costs related to the safety upgrades and modifications to all vessels fitted with its ECS, including all previously delivered vessels. There are now multiple layers of safety in place to shutdown the ECS and prevent its operation if necessary, even in emergency manual mode. Techcross has been busy sending engineers to attend to vessels all over the world to complete the upgrades, but expects to take up to one year to complete modifications on all the vessels affected.

In addition, Techcross has closely co-operated with classification societies after the incidents to conduct various risk assessments including hazard and operability reviews, hydrogen gas safety tests, failure mode and effects analysis (FMEA) and software verification. The FMEA was conducted in early October 2013 with the American Bureau of Shipping in Houston and is thought to be the industry’s first FMEA with class for a BWTS.

Before the incidents, Techcross had acquired plan approvals for each vessel from class societies, completed hazard identifications for installation on five different type of vessels, also in conjunction with class, and conducted hydrogen gas safety tests by simulation and onboard testing at independent laboratories. “With all these risk assessments, Techcross has shown a strong commitment for improving safety of crew and vessel,” Mr Yoon said.

Techcross has accepted the two unfortunate incidents with its system as a good learning experience to improve safety and crew training, including the importance of conducting risk assessments with class. The company hopes that by openly sharing with all stakeholders about important operational experiences, whether positive or negative, the entire industry will benefit from the development of not only more effective systems, but ones that are safer and easier to operate. “Safety is a top priority for Techcross,” Mr Yoon said. BWTT