Improving brewery sustainability performance

By Nalco

Nalco’s innovative 3D TRASAR Technology for Cooling Water contributes to the sustainable development of operations, and optimizes operational efficiency. It is also a 2008 winner of the US Presidential Green Chemistry Challenge award.

“New development and rising standards of living are expected to boost industrial water use both in real terms and as a percentage of global water withdrawals”

Background

The global brewing market is consolidating very rapidly. At the same time, beer consumption in Western Europe is shrinking by 1% to 2% every year. This is forcing suppliers to this market to become more and more competitive and hence to work more efficiently. Additionally, Integrated Pollution Prevention and Control legislation, and emerging sustainability commitments have increased pressure on brewers to lower their natural resource consumption and associated emissions and waste.

This has translated into new Key Performance Indicators (KPIs) that are now being widely used by the brewing industry. It is common practice to evaluate the use rate of natural resources proportionate to beer production, expressing use rate per hectolitre of product. The most important sustainability criteria for brewers are:

• Water consumption expressed as hectolitres of water per hectolitre of beer
• Energy consumption expressed as MJ per hectolitre of beer
• Electricity usage in kW per hectolitre of beer

These KPIs are now starting to be used globally to compare the efficiency of different production sites, or more specifically to compare different departments or unit operations within a brewery.

Main Challenges

The packaging hall is responsible for a major portion of all energy and water use in a brewery, and is under constant scrutiny by management to identify areas for improvement. Within the packaging hall, a tunnel pasteuriser can use as much as 20% of all water and energy used in a brewery. It is vital that the thermal balance in the various zones within the pasteurizer is constantly maintained. Many parameters influence this thermal balance, and any one can negatively impact the water and energy consumption of the machine if not kept under control. The most important parameters are:

• Line efficiency (starts and stops create thermal imbalance)
• Microbiological slime formation (will cause fouling of spraying systems and recirculation pump screens)
• Mixing of water from adjacent zones (will cause warm water to flow into a colder zone or vice versa)
• Leaking steam or make up water valves (will introduced hot/cold flows in an uncontrolled manner)

Current Situation

A major international brewery group asked Nalco to identify opportunities to contribute to the achievement of its sustainability goals at a site in Western Europe.

Management at the site were looking to reduce water use, energy use, and CO2 emissions per hectolitre of beer by 10% by the end of 2010. Initially, Nalco was asked to evaluate the operation of one of the bottle lines. The initial focus for the customer was to reduce the number of off-line cleans (and the associated excessive water use) needed to keep the pasteuriser in an acceptable condition. Cleaning of screens and spraying systems was necessary because of the rapid build-up of microbiological slime, despite ongoing treatment with a non-oxidising biocide.

Investigation of the water balance in the machine using a 3D TRASAR technology diagnostic study, revealed that there was major unplanned mixing taking place between waters from different temperature zones. In addition, due to the unpredictability of the amount of fresh water being fed to the pasteuriser, it was not possible to maintain the biocide treatment at the levels necessary to exert the microbiological control needed. As a consequence of temperature variability coupled with ineffective biocide application, spray nozzles and pump screens were continuously being blocked by slime. As a result, water and energy consumption per hectolitre was excessive, with water consumption at 0.9-1.35 hectolitres per hectolitre of beer, and energy use at 25-30KJ per hectolitre of beer. This represented a total water demand of 15-20 m3 per hour for the unit. A clear additional focus for the customer was identification of better ways in which to monitor the water quality parameters impacting pasteuriser cleanliness.

Action Plan

In order to optimise the operation of the pasteuriser, Nalco took the following steps with the customer:

• Replacement of the slow-acting non-oxidising biocide with a bromine-based oxidising biocide programme.
• Automation of biocide dosing using a free halogen analyser. This ensured that the biocide dosage was related to pasteuriser operation.
• Introduction of 3D TRASAR technology to continuously monitor the most important parameters that could impact pasteuriser cleanliness (including redox potential for biocide control, free halogen, turbidity, and pH). This enabled continuous recording of data, and analyses generated by the 3D TRASAR programme were then used to optimise treatment settings and results.

In the second phase of the investigation, the customer optimised the pasteuriser spraying system, making sure that no blending of water from different zones occurred. A regular maintenance programme was then put in place to remove glass particles coming from broken bottles, which had previously blocked filters and prejudiced optimum water distribution.

Results

This approach resulted in a 55% reduction in the fresh water demand for the unit, down to 7-9 m3 per hour, reducing the KPI values by 65% for water (to 0.4 hectolitres of water per hectolitre of beer), and by 31% for energy (to 18 MJ per hectolitre). Both impacts exceeded the brewery's sustainability target of 10% reduction in water and energy per hectolitre of beer by 2010.

On an annual basis, this delivered a saving of €45,000 in energy costs per year, and €20,000 in water costs per year for the pasteuriser concerned. The annual energy savings were equivalent to over 4,350,000 MJ, representing 225 tonnes of CO2 emissions per year. Elimination of much of the weekly cleaning and maintenance activity reduced the number of cleaning events by 80% per year. Demand for cleaning chemicals was also reduced by 90%, down from 15 tonnes per year to 2 tonnes per year. Based on the experience with this line, the customer decided to implement 3D TRASAR technology on the remaining 3 pasteurisers, 2 bottle warmers. As a result of the much improved monitoring and control of water quality for the canning line, an alternative can type with unlacquered tabs could be used at an annualised saving of €313,000 and with a payback on the initial investment required of less than one year.