Charging On Full Steam Ahead in Slovakia

Online Editor

Annemarie Wittmann presents a case study showing how 72 tonnes of steam was put to good use in a sugar beet operation

In process engineering, the exact observance of pressures in vacuum-assisted processes is an important parameter for ensuring optimum efficiency and the best possible product quality.

Transforming sugar beet into pure crystallised sugar is a multi-stage process that uses a large quantity of steam. In the southern Slovakian town of Sered, Slovensk√© Cukrovary processes around 5,000 tonnes of sugar beet every day. As part of the global Agrana Group, the company’s top priorities are sustainable processes, energy efficiency and the careful use of resources. These values were also reflected when an entirely new steam supply system for the factory was fitted in late summer 2021. For this major project, the company found partners in Bosch and general contractor PPA Controll. “Both companies pooled expertise that enabled professional management and implementation,” says Marek Ivanovic, head of the Bosch industrial boiler team in Slovakia.

A ZFR Universal steam boiler system forms the core of the new boiler house, which PPA Controll built from scratch in the space of six months. The team from Bosch configured and manufactured the complete boiler system precisely according to the specific customer requirements. To keep the steam generation process as sustainable as possible, the boilers are also configured for biogas operation. The factory treats production wastewater created by the beet processing and uses it to generate biogas, which partially replaces the fossil secondary fuel of natural gas. The NOx emissions are under 80mg/Nm³. Another feature of the system is the boiler design – each of the boilers is equipped with two independent burners and flue gas paths, which enables full flexibility both in single and double-flame tube operation and reduce fuel-intensive burner switching cycles. Its efficiency of almost 98% shows that it is even possible to generate large quantities of steam of up to 36t/h per boiler in a particularly efficient manner. The system is completed by components such as economisers, air preheating systems and oxygen control systems. These help to return process-related waste heat back into the boilers in an environmentally friendly manner and to optimise the combustion quality.

Water Treatment And Analysis

As a systems supplier, Bosch also provided modules for feed water treatment and water analysis. The feed water system thermally treats high volumes of condensate from production processes and fresh water and has a very large storage capacity of 50m3. A water analyser ensures reliable system protection, with sophisticated sensors continuously measuring and checking the water parameters and transferring the values to the system control unit. Slovenské Cukrovary also uses a control system from Bosch. This solution not only brings together boilers and components in a single system and controls them fully automatically, it also implements a remote connection and a digital efficiency assistant, which help the operator to optimise steam processes while the system is in operation.

The new steam concept makes production processes at Slovensk√© Cukrovary more efficient, more sustainable and future-proof. It was not only the technology but also the project management that was of high quality. “Few interfaces, experiences from comparable applications and the cooperative collaboration between Bosch and PPA Controll made the major project a success,” summarises Ivanovic.

Annemarie Wittmann is with Bosch Industriekessel