12 MW Biomass Boiler House - Limbaži, Latvia

A successful boiler house project starts with good engineering. The quality of the design determines not only how the plant is built, but also how efficiently, reliably and safely it will operate throughout its lifetime.

Every boiler house is unique. Greenfield projects normally provide greater flexibility, allowing the technological concept and equipment layout to be developed from the ground up with relatively few restrictions. Retrofit projects are a different challenge: the new plant must be integrated into the existing infrastructure while retaining and reusing as much of the existing installation as technically and economically reasonable.

This was the case with the 12 MW nominal + recovered capacity biomass-fired district heating boiler house reconstruction in Limbaži, Latvia, implemented for the local district heating company Limbažu Siltums.

FERGY carried out the project on a turnkey basis, covering the complete implementation cycle: development of the full design documentation, permit application, civil and structural works including equipment foundations, manufacturing and supply of the technological equipment, erection, electrical and automation works, start-up, commissioning and performance adjustment.

The core of the new plant consists of two complete biomass boiler islands with a total installed capacity of 12 MW. Each boiler line incorporates a moving step-grate combustion system and vertical hot-water boiler, forming the FERGY KAP + AK technological solution.

The project scope also included a direct-contact flue gas condensing system (FGC) for additional heat recovery, together with a complete flue-gas treatment system incorporating mechanical separation (MC) and electrostatic precipitation (ESP). This combination provides both improved plant efficiency and effective particulate emission control.

As part of the project, FERGY also completely rebuilt the biomass fuel storage and handling system, including concrete works, a new walking-floor system and fuel chain conveyors supplying both boiler lines.

The wider balance-of-plant scope included the insulated free-standing chimney, heat exchangers, water-side piping and pumping systems, combustion-air and flue-gas ducting, flue-gas fans, ash-handling interfaces, complete boiler house automation and the associated electrical installations.

The result is a comprehensively modernised biomass district heating plant with increased installed capacity, significantly improved overall energy efficiency and an upgraded flue-gas cleaning system designed to meet current environmental and operational requirements.

For FERGY, the Limbaži project is also a good example of what a true retrofit project requires: not simply replacing individual pieces of equipment, but developing an integrated engineering solution in which the existing infrastructure, new boiler islands, fuel handling, heat recovery, flue-gas treatment, hydraulics, electrical systems and automation operate as one complete plant.