Raise a glass to greater energy efficiency

2014-11-07 - High efficiency ABB generator helps German brewery save energy.

Bavarian brewery Erdinger Weissbräu has installed an energy recovery system that generates electricity while regulating the pressure of its process steam. A central component of the solution is a highly efficient IE4 (International Efficiency class 4) generator from ABB.

Erdinger Weissbräu is an independent brewery located in Erding, around 30 kilometers northeast of Munich, Germany. Successfully combining traditional methods and innovative technology, the brewery has established a strong position in both the German and international markets. The company’s annual production totals 1.72 million hectoliters and its best-known product is Erdinger Weissbier, a wheat beer brand that is now recognized by more than 80% of people in Germany.

In terms of energy, Erdinger Weissbräu takes an integrated cost and environment-oriented approach. By upgrading its technology and implementing efficient energy management, it has succeeded in reducing its energy requirements by 40 % per hectoliter over the past few years.

Brew kettles heated by steam
At the heart of the brewery are two ultra-modern brewhouses, and the process combines state-of-the-art technology with traditional brewing practices. The brewhouses were once dominated by huge copper pans, but today barley and wheat malts are mashed in tuns made of stainless steel, which are easier to clean than traditional copper pans.

Any excess heat generated during brewing is mainly fed back into the heating cycle, providing an 80 % saving in primary energy. The brewery makes further energy savings with its new energy recovery solution, an Energy Module that generates electricity using the hot process steam that heats the brew kettles.

Additional energy generated
The Energy Module was supplied by ENVA Systems GmbH, which is based in Marl, northwest of Dortmund. ENVA Systems specializes in the generation of electricity from low pressure steam and waste heat. The Energy Module is based on a method that has been proven in practical applications and is ideal for optimizing steam processes in breweries. It uses a rotating expander coupled to a generator to reduce the high pressure of the boiler steam to match the process needs. At the same time it converts the energy contained in the steam into mechanical and then electrical energy. No additional fuel is needed.

Production of steam in a boiler can only take place at a specific pressure level, which means that the pressure of the steam in the network has to be reduced before it can be utilized in the process. At the brewery this was previously done by means of a pressure reducing station. As the ENVA Systems Energy Module generates electricity while reducing the steam pressure, the pressure reduction process has become significantly more energy efficient and environmentally friendly since the module was installed in early 2013.

The Energy Module is used in place of a mechanical pressure reduction valve between two parts of the steam network operating at pressures of 9.5 and 6 bar. The heart of the module is the expander, which reduces the steam pressure and is connected to the generator via a special coupling. Following expansion, the steam is at a pressure of 6 bar, which is exactly the level needed for the downstream units and heat exchangers. At a steam flow rate of approximately 5.5 t/h, the Energy Module feeds more than 50 kW of electricity into the brewery's electricity network.

Complete electrical solution from expander shaft to network
The main components of the Energy Module are the expander, generator and control cabinet, which are mounted on a compact base with a soundproof hood. The module can optionally include additional instrumentation and control equipment. ABB supplied the complete electrical solution from the expander shaft to the network:

  • ABB IE4 induction generator
  • Dodge Para-Flex coupling
  • Control cabinet with SPS AC500 to control the expander / generator set
  • Low voltage network connection equipment from ABB STOTZ-KONTAKT
  • Monitoring of the expansion unit via the ABB Service Internet Cloud

IE4 generator delivers higher electricity yield
The Energy Module supplied to Erdinger Weissbräu is the first unit in Germany to incorporate an IE4 induction generator from ABB. In fact, ABB is the first manufacturer to introduce a range of low voltage induction motors in the Super Premium efficiency class. Rated at 75-375 kW in frame sizes 280-355, the 2-, 4-, and 6-pole motors are available for 400 V, 50 Hz and 440/460 V, 60 Hz. Targeted in particular at process industries, the IE4 motors are based on ABB’s proven and robust induction platform.

IE4 motors and generators from ABB offer the highest level of efficiency currently available on the market. In the case of the Energy Module supplied by ENVA Systems, the use of an IE4 generator boosts the electricity yield from the pressure reduction process by approximately 3%. This is equivalent to an annual increase of more than 7,500 kWh.

The efficiency of the system is therefore significantly improved by using an IE4 product instead of a lower efficiency generator. Over the lifetime of the expansion unit this results in a substantial increase in the energy produced.

Significant savings
The ENVA Systems Energy Module offers Erdinger Weissbräu considerable benefits. The energy contained in the low pressure steam is recovered, and at the same time the pressure and temperature of the steam is adapted to meet the requirements of downstream processes. The system is configured in a fail-safe manner, so that the brewing process takes priority over electricity generation in the event of a failure. The Energy Module is installed in a steam pipe (fitted with its own safety valves) which bypasses the conventional pressure reducing station. This means that the brewing operation can continue as normal during maintenance work and also when there are fluctuations in the steam supply.

The Energy Module generates approximately 250,000 kWh of electricity for the brewery’s network each year. As a result Erdinger Weissbräu can significantly cut its external electricity procurement and reduce its overall environmental impact.

The use of an IE4 generator from ABB increases the electricity yield by around 3 % when compared to a lower efficiency generator.

Photo by Erdinger Weissbräu brewery

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