From Waste to Energy – Successfully and Safely

The Riverside Resource Recovery Energy from Waste Facility, the largest such facility in the United Kingdom, is located on the bank of the River Thames in London. Metso’s automation solutions play a significant role in managing the waste-to-energy plant successfully and safely. The plant produces around 478,000 MWh of electricity a year, which is the equivalent produced by burning 191,000 tons of coal.

Municipal household waste from six London boroughs is taken to Riverside, usually by barge. The amount of the waste is massive, but so is the capacity of the plant: It is expected to manage an average of 585,000 tons of waste per year, but it has a capacity of 670,000 tons.

On arrival at the Riverside facility, the waste is taken to the main plant building and tipped into a storage bunker. Each of the three boilers is charged with waste, each with a throughput of up to 30 tons per hour. The waste then enters the combustion chamber via a vertical feed chute.

Steam is generated through heat-transfer from the combustion process into waterfilled boiler tubes. Superheated steam from the boilers is used to operate the 72 MW turbo generating unit, which is connected to the national grid.

Waste does not have a standard heating value like most carbon-based liquid, solid, or gas fuels, which means the heat value of the waste can vary considerably. Controlling the combustion process therefore requires many variable inputs to ensure a stable output as well as a combustion process that continuously operates safely and within acceptable environmental limits.

The process control at the Riverside Energy from Waste Plant is achieved by using a Metso DNA automation system. Metso DNA is a single integrated automation and information platform for process control, high-speed machine control, batch control, and SIL-certified safety controls. It offers advanced optimization, mechanical condition monitoring, and process performance monitoring.

At the Riverside Energy from Waste Plant, Metso DNA gathers information from a large number of sensors – everything from the initial waste-handling process to the composition of the emission gasses at the stack to the pressure of the steam at the turbine and the conditions in the various auxiliary systems.

The sheer quantity of information available could be overwhelming, but Metso DNA displays it in such a way
that only those areas requiring attention are highlighted while still making all information visible.

Operators can easily view both live and previous data simultaneously, thus enabling them to identify trends and to take any necessary remedial action as soon as possible. Likewise, this information can be displayed and easily accessed in readonly format by managers or engineers, and it is used to provide user-friendly management and operational reports.

Not only can the operators see what is happening as it is happening, they can also do something about it: A wide range of adjustments can be made and parameters monitored electronically from the operator’s position. Traditionally, this would, in many cases, have involved someone physically adjusting a valve or checking a reading. This facet of the system is important with a small operating team on shift. Online changes to equipment have also been carried out successfully and safely, minimizing disruption to the routine operation of the plant.

With detailed historical information stored in a database, comparison and forecast reports can be produced quickly and easily.

In a world where the amount of municipal waste continues to mount, Metso sees significant potential for growth for the use of recycled waste. The focus of the company’s research and development activities is on environmental technology solutions that represent new technologies, such as waste utilization.

The way Metso sees it, a company aiming to solve global social and environmental challenges will succeed in the long term and will create value and well-being for all the company’s stakeholders as well as society.

Metso believes that one of the best ways to promote sustainable development is to innovate in technologies and to change current ways of operating to align with principles of sustainability. This is how Metso wants to take part in creating a more sustainable future.