Nardi is the world’s largest manufacturer of kilns and its expertise covers drying of softwoods and hardwoods, heat treatment of pallets to ISPM 15 requirements and steaming timber such as beech for aesthetic effect.
Another, and increasingly important, area of the company’s production is wood-fired boilers, which provide a commercially attractive alternative to gas, electricity or oil systems for heating kilns and buildings.
A major reason for the growth in importance of wood-fired boilers is the rapidly rising cost of energy – frequently cited as one of the most pressing areas of concern for industry. However, there are also good environmental arguments which further reinforce the fact that, for wood processing industries, the word ‘waste’ has always been a misnomer.
“Using some or all of this ‘waste’ to produce energy makes sound business sense”, said Justin Peckham, managing director of Nardi’s UK and Irish agent Woodtech Machinery.
“It makes it easier to manage the material, eliminates the cost of transport – which itself has environmental benefits – and over the long term it provides a cheaper source of energy compared with gas, electricity or oil.
“Of course, there is the initial capital cost of the wood-fired system, but the Carbon Trust offers unsecured interest-free loans to ‘bridge’ the gap, with repayments covered by the savings in energy costs over the payback period. Our boilers are eligible for Carbon Trust loans and Woodtech can assist customers with the application process.”
Solid biomass
Nardi’s heavy-duty steel boilers have been developed specifically for solid biomass. The range includes models for heating water (110OC) or superheated water (150OC), thermal oil (280OC) and low pressure (0.7bar 115OC) and medium pressure (12bar 190OC) steam. Output capacities run from 100kW to 4.65MW.
The boilers are available in two versions – one for relatively dry material (up to 50% moisture content), with the chips fed directly to the combustion chamber, and the other for wetter material, in which chips are pre-dried in a mobile grid before combustion using hot air diverted back from the boiler.
Woodtech has just sold one of the latter type to Duchy Timber in Cornwall, which produces carcassing, fencing and pallets using a mix of UK softwoods. Due for installation in March, the order is for a complete system including two 100m3 kilns and a 1.4MW WA-G boiler.
“In the case of Duchy Timber, a pusher is used for feeding chips into the boiler – rather than an auger ‘corkscrew’. The pusher can cope with larger pieces of wood, so offcuts from the moulding and cross-cutting lines can be fed to the boiler as well as material from the chipper on the main sawmilling line.
“If required, however, we can also supply chippers/ shredders to customers.”
Nardi boilers are designed to provide high thermal exchange rates and reduced fuel consumption over a long working life. They are easy to maintain, including cleaning of the pipes, which ensures minimum downtime.
Dual-fuel systems
Dual-fuel systems are also available, with the wood-fired boiler complemented by an oil, gas or electricity boiler that kicks in automatically if there is any interruption in the supply of chips/offcuts – which can be an attractive option, especially for companies running the plant 24/7.
Emissions regulations are met with a multi-cyclone cleaning unit to remove any solid particles from the smoke emitted from the chimney, and a PLC system that provides accurate control over the boiler operation, including burning the gases produced to remove chemicals in the mix.
“In addition to turnkey installations we can easily retrofit a Nardi wood-fired boiler to existing kilns that are currently fuelled by other types of energy sources,” said Mr Peckham.
“The systems can also be installed to provide the heating for buildings, which is a market with huge potential for expansion,” he added.
