Turning off the oil

THE Murau Brewery in Austria used to consume 700,000 litres of heating oil a year for beer production. Since April 2014, the cooperative brewery with an annual beer output of about 280,000 hectolitres, has been producing its beer with heat from the biomass cogeneration plant of the municipal utilities Murauer Stadtwerke GmbH. This means that in the brewery, fossil fuels are no longer being burned for making the beer. This change-over t o regional, regeneratively produced, CO₂-neutral thermal energy has been made possible not least by the modification of the brewhouse to incorporate Steinecker's EquiTherm system, where the entire energy required for mashing is provided by the wort cooling process. Since the brewery wanted to preserve the traditional character of the existing brewhouse with its copper hoods, Krones integrated the technology into the extant copper vessels.

The entire interiors of the mash tuns and the essential part of the wort boiling equipment were modified to feature the very latest Steinecker technology. The existing wort cooler was expanded to incorporate the EquiTherm system. The two mash tuns were given the interior and the substructure of the ShakesBeer EcoPlus in an energy-economical design. At the same time, Krones built a new mash mixer made of copper for each mash tun. The wort copper was modified to include the Stromboli wort boiling system with an external boiler, and fitted with additional heat exchangers. Moreover, the wort is now no longer heated using the external boiler, but with a lauteredwort heater during recirculation pumping, which means the wort is already at boiling temperature when it reaches the copper.

The heart of the system is the stratified energy storage tank with a capacity of 110,000 litres, where firstly the heat from the EquiTherm is stored, and secondly the thermal energy required in each case for the various heat consumers can be taken from the different heat layer levels. "The big advantage here is that thanks to the buffer storage tank we can start up the consumers at precisely the temperatures that are actually needed there. We used to do everything with steam at 160 degrees Celsius", explains Technical Director and Brewmaster Günter Kecht. "We use three temperatures: we need water at 115 degrees in the brewhouse only for boiling, 105 degrees for the bottle washer and 95 degrees for the rest."

The EquiTherm energy recirculation system
The EquiTherm is a system designed to withdraw energy from the brewing process at a suitable point and feed it back in again at another point. With the energy recirculation capability thus created, enormous savings can be achieved in the brewhouse of up to 30% in terms of thermal energy and 20% in terms of electricity for the infusion and the decoction process – and given ideal conditions quite definitely even more. EquiTherm is the first concept available that assures holistic optimisation of the thermal balance in the production operation, and thus also prevents the excess of warm water encountered in most brewhouses. The EquiTherm system comprises three separate but linked up
process units: the ShakesBeer EcoPlus mash tun system, in which the heat flow is increased by a counterflow heat exchanger principle The turbulent flow pattern of the mash along the heating surface improves heat transfer, and thus the heat-up rate. The layered energy storage tank is the heartof the system, with its stratified charging pipe. It optimises density/temperature dependent utilisation of the energy storage tank. The crucial factor in how the energy recirculation capability of the EquiTherm system functions is the interaction between the mash kettle and a particularly low-loss energy recovery capability between the boiling and cooling stages.

Hot water instead of steam
The state of the art in most breweries is to use steam at 130 to 150 degrees Celsius. At the Murau Brewery, the steam temperature in the past would reach 160oC. Because of its discontinuous heat production, plus high condensate and post-evaporation losses, a steam boiler is relatively inefficient in many breweries. Using the EquiTherm system now enables Murau's beer to be brewed with much less energy, and at an ultra-low temperature level. The highest temperature required in the "Murau Low-Temperature Brewery" is meanwhile needed for only a few minutes at the start of wort boiling where the brewery manages with hot water at less than 115 degrees Celsius. The heat is transferred in Murau by a low loss heat transfer station and an energy storage tank designed specifically as part of Steinecker's EquiTherm system for covering peak loads and recovering heat, which in this case supplies the entire brewery with regenerative and recuperative heat.

The CO₂-neutral brewery
The Murau Brewery has long since signed up to a corporate philosophy that places eco-awareness at the center of production – to become a CO₂-neutral brewery. The cooperative brewery in Upper Styria feels a deep sense of commitment to the bio-region surrounding it, and the energy vision of the climate alliance community Murau, which aims to achieve energy self-sufficiency by 2015. The electricity required in the brewery is generated by the municipal utilities using hydro-electric power plants. Whilst power supply in the Murau district comes from the surrounding region in its entirety, now that the brewery's heat supply has been interfaced a very significant step has been taken towards the "Energy vision Murau – a region on its way to energyindependence!"

The brewery is now being supplied 100% with regeneratively produced electricity and bio-heat. The road map that the brewery has followed here, under Board chairman Johann Lassacher, managing director Josef Rieberer and Brewmasters Günter Kecht and Christoph Lippert-Pagany, is most probably unique in the entire brewing sector: energy is not only being saved by changing over the system of heat provision, but above all by lowering the "process heat temperature" as well.

Brewing beer without any fossil fuels
The foundations were put in place for the "District heat from biomass, not heating oil" project when a district heat pipeline was laid for the future supply of hot water in the brewery's courtyard. The intra-plant modification work for creating the more energy efficient hot-water system now required was carried out in several different project stages. These included integration of the district heat supply with a buffer storage tank and the modification of the steam network in the plant with a hot-water supply, linking it up to major consumers like the bottle washer, the cask washing system, the container washing system, the flash pasteuriser, the hot water supply and the CIP equipment. At these machine consumers, all the heat exchanger surfaces were modified. "In all of this, we have not compromised in the slightest on hygiene", said Brewmaster Günter Kecht. "To sterilise the casks or pipes, for instance, we operate our own small steam boiler, which uses biogas from the wastewater treatment plant as fuel." As an alternative to biogas as a fuel, this steam boiler still possesses an electric heater to be on the safe side. The existing oil-steam boiler has been decommissioned and conserved.

Changing over the brewhouse
The challenge was changing over the brewhouse in the Murau Brewery from steam to hot water, because the municipal utilities could only deliver hot water at a maximum temperature of 115^oC. For this, Second Brewmaster at Murau, Christoph Lippert-Pagany spoke with Steinecker. The heating plant is located 2.2km away from the brewery, and the hot water is transported by an insulated pipe 150mm in diameter. The brewery stipulated that the changeover to hot water would not entail any alteration whatsoever in quality. This is assured by the buffer tank, with its 110m³ capacity, in conjunction with the new Steinecker technology. At the same time, the brewery's overall energy-efficiency was to be improved.

As an emergency reserve for the local heat network, the Murau municipal utilities have linked the new local heating plant to an older existing district heating plant that had already been set up some years ago by a group of farmers, thus assuring that reciprocal synergies are utilised and providing an insurance against failure for both network operators. As an emergency reserve for the Murau Brewery and the state hospital, the existing oil-fired units have been integrated into the control system, and will automatically take over to supply the heat in the event of a failure at the local heat supply network. The Murau-Stolzalpe biomass cogeneration plant is fully automated throughout.