The combustion of wood waste poses unique challenges that require specialised expertise. Variable fuel moisture, sizing and form, can make wood waste difficult to burn even for the most experienced operators. We have encountered many examples of poorly designed wood fired boiler plant that fail to meet the most basic of combustion criteria, including those supplied by established boiler manufacturers. With increasing particulate emission limits and ever-present hazards such as airheater and dust collector catastrophic fires, these boilers can impose ongoing challenges for plant management.
Examples of our specialized expertise that relates specifically to the Paper and Wood Processing sector include:
Analysis of Combustion Problems: Design Boiler has been engaged to address significant combustion problems on biomass / wood waste grate fired boilers. Poor combustion in wood fired grate boilers can cause several operational problems including:
(a) back end metal fires in air heaters and dust collectors,
(b) high particulate emission issues,
(c) furnace pressure control problems;
(d) an inability to achieve the rated MCR output from the boiler and
(e) difficulties achieving superheater steam temperatures.
We have addressed combustion problems on a number of biomass/wood fired boilers by modifying combustion controls and redesigning the secondary air system. A relevant case study that discusses a similar problem may be found here.
Design of a Sawdust Fired Hot Water Boiler: A small wood processing facility required a means of producing hot water to run drying kilns for its production facility. The amount of heat required was about 2 MW and the only commercially available option was a small gas fired boiler. However, the cost of gas ruled out the gas fired unit as a viable option. The site produced a significant amount of waste saw dust and Design Boiler was engaged to design and install a small saw dust fired hot water boiler. The boiler was installed and commissioned successfully. A relevant case study relating to this capability may be found here.
Design modifications to an existing thermal oil plant: Whilst the majority of our work involves problems solving issues associated with steam plants, we also have expertise in thermal oil plants. A hardwood processing facility required additional heat for a planned production expansion. An obvious solution was to install an LNG tank and utilize a gas fired system. However, the project cost was prohibitive. The existing heat source was provided by a wood waste / biomass fired thermal oil heater which had been designed with a relatively high back end gas temperature to ensure a high incineration rate of the large amount of wood waste produced on the site. We redesigned the heater by increasing the heating surface of the existing unit which achieved the additional heat recovery required for the plant expansion. Read more.
Boiler Efficiency and Acceptance Testing: Our personnel have been involved in plant efficiency and boiler acceptance testing for contract verification purposes. We are capable and experienced in applying ASME, ISO and British Standards acceptance testing methods for both fired and HRSG boilers.
Catastrophic Metal Fire Investigation: A major fire developed in the back end of a wood waste fired boiler and caused extensive damage. The fire developed into a catastrophic metal fire and destroyed the boiler airheater and shut the entire plant down for over 12 months. Design Boiler was engaged by the insurance company to investigate the cause of the fire and determine how to prevent a reoccurrence of the fire if the boiler and airheater were repaired and reinstated. Following an extensive investigation, we identified a number of key defects with the design of the airheater in the form of tube orientation, tube diameter and tube spacing, along with significant limitations in the airheater sootblowing system. Also identified were major deficiencies in the instructions provided to operating personnel as to how to identify and extinguish an airheater fire. Read more.
Design Boiler’s broad range of specialised boiler design and testing services, along with its computer modelling resources are available to diagnose and troubleshoot boiler problems in the Paper and Wood Processing sector.
