Beyond the Comfort Zone How to Plug Energy Leaks

Who would not want to save energy to offset the impact of rising energy and raw material prices? The experts at Bayer Technology Services have developed a systematic methodology called the Energy Efficiency Check which helps users increase system energy efficiency.

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The chemical industry is currently grappling with the effects of steep increases in energy prices, climate change and the shrinking and highly competitive international marketplace. CO2 emissions and energy consumption are hot topics in the industry, and the two issues are closely related, providing sufficient motivation to increase the energy efficiency of production systems. Companies that are willing to take action can exploit significant opportunities to reduce operating costs, claims Andreas Jupke, who is head of the Process Analysis Group at Bayer Technology Services (BTS). The Energy Efficiency Check provides a systematic, comprehensive approach to energy consumption analysis and optimization.

Plugging energy leaks can reduce operating costs by between 5 and 20 percent, says Jupke, and he can now cite evidence from more than 100 reference projects which were carried out on behalf of internal and external customers worldwide. There are plenty of opportunities for tweaking production systems, and the improvements do not always involve major effort (or investment). Small changes can often produce big results. Jupke has found that in a surprising number of cases, the process is running in the comfort zone rather than at the optimum energy point, and this creates opportunities for users to increase energy efficiency. “The operations team is often not even aware of the key parameters that affect energy consumption,” reported Jupke. For example, a large, constant reflux flow is often maintained in distillation columns despite the fact that the flow could be reduced to match throughput.

A lot of energy is wasted during recycling of excessive amounts of raw materials and solvents. Efficient equipment also cuts energy consumption. Pumps, compressors, fans, agitators and conveyor systems are the most energy intensive devices. On pumps with throttle valves, half of the energy used by a pump is wasted at the control valves. This problem can easily be resolved by replacing the throttle valve with speed controls on the drive subsystem.

The goal of the Energy Check is to identify as many opportunities as possible and put together an action plan for the customer. The Energy Check is broken down into three phases: analysis, concept development and assessment. During the first phase, BTS collects and summarizes actual consumption data for the overall system, and this includes every step in the process. BTS also identifies the main power consumers for each type of energy. According to Jupke, customers are often surprised at the results. The goal is to identify all of the equipment that is using power in the complete process and highlight the items that are consuming the most energy. “Customers are often unaware that some pieces of equipment are using large amounts of power,” explained Jupke. Once the “bad actors” have been identified, the next step is to delve into the details.

Checklists, best practice catalogues and experts help the team to perform a detailed analysis of all the equipment that uses significant amounts of energy. The team is particularly interested in operating parameters, process control systems (especially at partial load) and process design. The development of strategies to improve heat integration and waste heat recovery plays a major role in the concept development phase, and Pinch analysis can be a very useful aid.

Brainstorming sessions with plant personnel can also make an invaluable contribution, because the people who operate the system often notice intuitively when things start to go wrong on “their” system. The analysis is not limited to the production process. The team also looks at peripheral equipment along with supply and disposal systems. Power consumption throughout the building is carefully scrutinized including the HVAC systems and insulation.

Focusing on efficiency

The wheat is separated from the chaff during the third and final phase of the Energy Efficiency Check. All of the action items which have been identified are assessed for:

• technical feasibility
• potential savings (energy and cost)
• cost of implementation
• profitability (ROI)

According to Jupke, experience shows that simply by optimizing system operation and running “close to the wind”, users can save up to ten percent compared to a system which is operating in the “comfort zone”. Energy consumption can be cut by roughly another ten percent by making targeted investments in the equipment and process design. Jupke says that the payback period is about three years.

At the end of the exercise, the customer receives a prioritized list of suggestions plus project data sheets as a roadmap for future implementation. Jupke also emphasized the importance of maintaining the focus over the long term. To help ensure sustainability, Bayer recently developed an innovative energy efficiency tool which makes system energy efficiency quantifiable. The expert from BTS would not be surprised if the tool were to become an industry standard in the field of energy efficiency.

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Keeping track of CO2

There is a close relationship between energy consumption and carbon dioxide emissions, and Bayer launched a program to cut CO2 emissions last year. The corporation uses the Climate Check, which was developed by BTS, as a systematic methodology for identifying opportunities to save energy.

The Climate Check is one of several lighthouse projects at Bayer which are designed to combat climate change. The big advantage of this approach is that for the first time the experts can assess the entire production process including all intermediates and all of the energy consumed. The Climate Check combines two elements, namely the Climate Footprint, which provides information on the effects of product production, and the Energy Efficiency Check which identifies opportunities to cut energy consumption. The footprint is similar to the carbon footprint. It indicates the CO2 equivalent emissions of a product.

“We include all of the emission-relevant elements of a product which a producer can influence, from a process pump to the logistics chain,” said Jupke. Once the footprint has been determined, the next step is to conduct the Energy Efficiency Check. The climate experts conduct an end-to-end analysis to identify ways of optimizing individual systems and processes. “We look for opportunities to reduce CO2 emissions. We then give them a weighting and prioritize them based on economic criteria. The Climate Check gives the user an objective basis for making decisions,” explained Jupke. Within the framework of the Bayer Climate Program, BTS is currently looking at 100 systems worldwide which produce about 85% of emissions.

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