Over the last four decades, the UK woodworking industry has witnessed remarkable advancements in wood dust extraction systems and wood waste burning equipment. From the early days of rudimentary dust collection to state-of-the-art and highly efficient systems, the industry has evolved dramatically, signifying a growing awareness of the importance of environmental sustainability and workplace safety.
Previously, dust extraction systems relied on large-diameter, straightforward cyclones. However, these systems proved inadequate in terms of handling the fine dust generated by modern machining methods, such as CNC routers and high-speed MDF profiling, which became more common with the increased use of MDF and MFC.
The early dust extraction systems in the UK were primarily from Scandinavia, with prominent manufacturers such as Moldow A/S, Nordfab A/S and Aagaard A/S. These companies quickly established subsidiaries in the UK, such as Moldow Ltd., Nordfab (GB) Ltd. and Aagaard UK Ltd.
Originally, Ranheat A/S was a subsidiary of Nordfab A/S, focusing on small boilers for the agricultural sector. Nordfab collaborated with boiler manufacturers such as Danstoker and Justsen to create combustion and feed systems. Under the leadership of Knud Ostergard-Nielson, Ranheat A/S eventually became an independent company, although it still maintained a close relationship with Nordfab GB. In the UK, Dick Parker, who had been a director at Nordfab, established Nordist Ltd., specialising in Nordfab installations.
In 1990, Ranheat was acquired by its current owners, Chris and Barbara Franklin, and manufacturing operations began in Northamptonshire. Meanwhile, Ostergard-Nielson took over Weiss Germany, a large boiler manufacturer within the Nordfab Group. Ranheat initially served the agricultural sector but adapted to the growing demand in the UK woodworking industry, particularly with the rise of MDF and other artificial timber products. This expansion necessitated the development of new combustion systems and flue gas cleaning technologies, which prompted Ranheat Engineering to increasingly concentrate on the UK woodworking industry.
In the early days, dust extraction systems primarily utilised bag filters with an auger discharging through a rotary valve. Over time, as filters evolved, chain filters became more common. Eventually, cyclone filters, such as the Indusvent Superblower manufactured by JKF A/S, gained popularity.
Today, there are over 100 companies specialising in dust extraction system installation in the UK. British manufacturers have entered the scene, producing various filter types, including screw, chain and cyclone filters. Notable examples include Wood-Waste Control (Engineering) Ltd., Dustraction and the Woodwork Dust Control Company.
Combined closed loop cyclone feeding superblower feeding a boiler storage silo. Indusvent extraction, Ranheat silo.
Continuous refinements have been made to wood dust extraction systems, emphasising the enhanced design efficiency of the primary extract fans and the incorporation of multiple fans. An important innovation involved moving the fans to the clean side of the system. This ensured that wood waste would bypass the fan, allowing only clean air through. This change facilitated the use of backwards-inclined fan impellers which were not like traditional paddle-blade fans known for their lower efficiencies.
Furthermore, the development and cost reduction of frequency controllers played a pivotal role in regulating fan speed and decreasing operational expenses. The implementation of an automatic gate closure system also ensured that blast gates would automatically shut when machines were not in use or turned off, contributing to a more efficient and cost-effective dust extraction system.
Once the wood waste has been gathered and the extraction air has been filtered, the next step involves deciding on how to manage the wood waste. There are several choices available. You can position the filter above a dedicated room (often called a chip store), which requires periodic emptying. Alternatively, you can dispose of the wood waste in a skip. Other alternatives include blowing it into a trailer or roll-on/roll-off (ro-ro) skip or storing it in a silo to fuel a wood-burning system.
With the continuous rise in energy costs, the option to burn wood waste has become increasingly attractive for many businesses.
Chain filter feeding “bunker” silo. Moldow chain filter, Ranheat silo.
Ranheat expanded its offerings by developing a range of warm air heaters to complement the company’s line of wood-fired boilers. In larger installations, Ranheat integrates Danstoker pressure vessels alongside its various combustion systems.
In 2013, the UK imposed more stringent emission limits for industrial wood-fired systems, reducing them from 200mg to 60mg, while also introducing a strict NOx limit. Around the same time, the Renewable Heat Incentive (RHI) was launched to promote biomass usage, benefiting the woodworking industry.
However, the RHI, now closed to new applicants, created an uneven market as it applied solely to boilers, excluding warm air units. Following the scheme’s closure, there has been a resurgence in warm air systems. The RHI also raised awareness among end-users about obtaining the correct permits and permissions from local authorities as payments were contingent on compliance with these regulations.
Regrettably, not all suppliers or manufacturers informed customers about these requirements. In 2018, the Medium Combustion Plant Directive (MCPD) was introduced to encompass all combustion processes. Importantly, this directive is retroactive and affects all existing installations. As a result, all current setups must comply with the MCPD, with deadlines set for 2025 for those exceeding 5MW and 2030 for those below 5MW.
Ceramic flue gas filtration system to meet new low particulate limits.
Existing installations can retrofit ceramic flue gas filters to ensure compliance with the new MCPD regulations. These filters follow a modular design, where each module can manage a specific volume of flue gases. When adapting existing boilers to meet the requirements, a selection of modular filters can be chosen based on the available space within the boiler room.
Ceramic flue gas filter fitted to a 1,100kW boiler.
The UK woodworking industry has witnessed a significant evolution over the last four decades, marked by advances in dust extraction systems, wood-waste management and emissions control. These changes reflect a growing commitment to environmental sustainability and regulatory compliance, shaping the industry’s future practices.
With soaring fuel, gas and oil prices, there has never been a greater incentive to use wood waste to heat your factory. To learn more about our industrial biomass boiler solutions, visit www.ranheat.com or contact us at [email protected] or by telephoning 01604 750005.