Engineering firm warns biomass builders on cutting costs

By Axiom Engineering Associates | November 22, 2016

Moves to make green energy more cost-effective, by cutting corners to reduce up-front costs, can prove to be an expensive mistake, a U.K. materials engineering company warns.

Axiom Engineering Associates has identified a spate of equipment failures where successful imported designs have been modified to make them cheaper, a process that leaves them much more susceptible to corrosion and failure.

The Teesside-based company, international experts in failure analysis, says U.K. firms are cutting costs by using carbon steel, rather than expensive stainless steels, in otherwise state-of-the-art biomass systems. Although this makes them cheaper, metallurgist Rene Hoyle has warned the move could prove very costly in the long-term. “This is new technology in the U.K.,” he said. “There is a very significant cost difference in using ordinary carbon steels, rather than stainless, but burning biomass is a very tricky process. When fresh wood is burnt it leeches acid which causes corrosion that can have a catastrophic effect on a system made from downgraded materials.”

Axiom was recently called in to examine a large wood-burning green energy system in the North-East. “The original design had come from Scandinavia and the specification called for much of it to be made from stainless steel,” Hoyle explained. “The principal contractor in the U.K. looked at the costs and, with a typical project management approach, cut back on materials expenditure by using carbon steels. Within two years of commissioning, corrosion issues were found which made extensive repairs necessary, and an expensive on-going maintenance and repair programme had to be put in place for the life of the asset.”

In another case, when corners were cut on a company’s new wood-burning boiler, the cost of repairs and on-going maintenance far outweighed the predicted savings.

Hoyle has also identified similar problems with waste incineration systems where cheaper stainless steels have also been used to spare up-front costs. “Biofuels don’t come out unscathed either,” he added. “A major bioethanol plant, which dries its waste for cattle feed, had been up-scaled from a French agricultural design, but mechanical aspects, such as fatigue loads and even shell thickness, were not reconsidered so failures started occurring within a few months of commissioning.”

Axiom came up with a bespoke modification which resolved the short-term issues and extended the drier’s service life.

Hoyle says the industry’s desire to save money could have an impact on bioenergy’s ability to play an important role in meeting the U.K.’s 2050 greenhouse gas emissions targets.

He warned, one of the underlying issues is that many of the latest green technologies are being developed by people not used to the chemical industry-type environment, and as such, they are not asking the right questions at the right time. “Those who have asked Axiom for support are benefitting from a wealth of knowledge and experience on many plants and in many industries, allowing safe but pragmatic designs to be developed in a cost-effective manner, using materials appropriate for the predicted operating conditions.  In most cases, if the right questions had been asked earlier in a project development, many of the subsequent issues would have been avoided.”