Accurate Flow Measurement in Steam & Specialty Gases in breweries – Case Study

Measurement Challenge/Difficulty:

Steam being used in breweries had always been overlooked as a source or “reusable” or “capturable” energy. Averaging Pitot tubes typically used were not only inaccurate, but still required costly pipe runs along with very regular and expensive maintenance and replacement. In generating steam, thermal mass meters had been used but presented some of the same problems. Brewers looking to improve their efficiencies needed a new method to obtain and measure a thermal mass balance around the plant for steam generation and usage. Specialty gases such as Carbon Dioxide, Nitrogen, and Chlorine were being used in the utilities and process areas of the brewery. All of these were measured with previously mentioned flowmeter technologies, usually inadequately. The brewers needed a better flowmeter that would reduce the use of expensive purchased gases or be able to monitor use of generated steam and energy demands more accurately.

In beer production, accurate temperature control is critical to any wort boiling kettle since it is a sensitive process and one of the most energy-intensive aspects of beer production. In this case, the kettle is a large vat with tubing coiled around the exterior wall. The tubing carries a mix of steam and water to heat the wort in the kettle. Modulating the proportion of steam vs. water in the tubing enables the brewery to control the thermal transfer profile of the batch process.

The wort boiling process demands a high volume of steam in its initial phase, enough to bring the large batch up to temperature quickly but without burning the wort at points of direct heat transfer. Once the entire contents of the wort kettle reach a boil, a much lower rate of steam feed can then be used to maintain a desirable temperature for the remainder of the heating cycle.

Previous Method:

Steam measurement was made with orifice plates, then averaging pitot tubes. Specialty gases were measured with thermal mass dispersion meters. All of these technologies had similar problems with pipe diameter restriction, maintenance and replacement frequency and costs, and inaccuracies of the devices. Vortex meters especially could not generate accurate readings at low flows in a condensed environment crowded with fittings and tight turns.

Solution:

V-Cones were installed, reducing operating costs and virtually eliminating replacement expenses. The accuracy of the flowmeters helped the brewery to better calculate their steam/heat balance. V-Cones on specialty gas lines helped reduce usage and more accurately measure produced Carbon Dioxide, resulting in a more economical production. V-Cones measuring Chlorine gas aided in the cleansing cycles thereby reducing gas purchases. V-Cones used in Nitrogen applications measured the gas more accurately, reducing the overall use of gas. Date Installed: 1997.