By implementing and optimizing energy management systems, industrial users can increase transparency and save energy, laying the foundation for more sustainable and efficient operations.
World events, resource availability and climbing energy prices have placed utility dependency in the global spotlight, causing manufacturers and consumers everywhere to focus on sustainable operational practices. Tier-one consumables – such as electricity, water and gas – along with tier-two products – like steam, compressed air and heat, which are generated using tier-one utilities – power everything within the walls of industrial facilities (Fig. 1). Optimizing resource usage is vital to sustainability and profitability.
In every industry, there are similar steps required to reduce energy consumption and increase operational efficiency.
- Identify areas for process improvement or optimization. This sometimes requires retrofits, but it is often achievable simply by using already-installed equipment more efficiently. Opportunities for improvement are revealed by accurately measuring process values and applying energy performance indicators in the right locations.
- Adjust operations according to optimization insights.
- Measure and track energy and emissions data and align this with progress reporting on efficiency goals.
This article will explore key utilities and identify several actions companies can take to work toward better energy efficiency and reduced emissions in enterprise operations.
Fig. 1. Utilities are at the core of every process plant, and optimizing efficiency is essential to achieving ambitious sustainability goals.
Process engineers and other subject-matter experts (SMEs) are tasked with spearheading these sorts of organization-wide efforts. Still, there are technical and human-centered challenges to navigate along the journey. These leaders have many questions on their minds as they grapple with achieving organizational objectives such as: “Reduce energy consumption and emissions by 25% by 2030.” Some of the questions many SMEs have include:
- Where do I start? Which opportunities have the greatest ROI potential?
- I know we need to align with industry standards and regulations, but which standards align with our goals?
- In our plant, we use a lot of steam, water, compressed air and heat, but exactly which processes require these utilities and in what amounts?
- I know we must measure energy consumption and efficiency as we make improvements, but where should we place instrumentation to measure these components best and identify opportunities for reduction? How much will these measurements cost, and what are the potential savings?
- How do we best track our carbon footprint, create and record emissions data and show progress toward goals?
- Who can help me with these improvements?
The answers to some of these questions are surprisingly simple, while others are understandably more complicated.
Identifying Opportunities to Reduce Consumption
Optimization efforts begin with creating context throughout entire plant operations by placing the right instruments in suitable locations. These instruments generate data, which can then be aggregated and pieced together. When analyzed appropriately, the resultant insights from data collected over time tell a plant story, providing personnel with a detailed understanding of their operations.
To ensure detailed and accurate information, teams should consider:
- Leveraging the knowledge of experts to help establish what should be measured and where measurement should be applied.
- Examining a facility holistically to identify strategic measurements that provide high-quality data. This information can then be leveraged for plant insights.
- Implementing advanced monitoring and diagnostics in the process using capable instruments. These types of efforts help progress plant digitalization strategies by providing troubleshooting, verification and predictive-maintenance data.
The correct information leads to actionable insights for efficiency enhancements, but the journey does not end here. Data collection must be continuous, informing efficiency gains and supporting compliance reporting. Additionally, the right software tools are needed to ease procedures for moving operational data to shareable reports, which in turn can be used to communicate wins throughout a company and demonstrate regulatory compliance.
Key Utility Applications for Efficiency Enhancements and Improvements
The following are a few specific application examples of monitoring and optimizing utility usage.
Heating and Cooling
There are a vast number of industry-specific heating and cooling processes and technologies. For this reason, customized approaches and specific measured values are needed to assess performance and improve output.
Energy loss is often high in boilers and industrial furnaces due to inefficient combustion, incorrect operation or poor maintenance and servicing. Measuring the efficiency of these systems is the best way to gauge losses and assess required remedial action. By monitoring fuel consumption, combustion air, flue gas temperature and the transmission rate of thermal energy, it is possible to create a clear picture of heat-generation efficiency.
The following actions should be taken in heating applications:
- Identify and quantify energy loss, such as the no-load or partial-load operation of a burner
- Assess and optimize boiler efficiency and consumption
- Minimize maintenance costs and downtime
- Quantify potential improvement measures, such as preheating combustion air
Another increasingly common strategy is recycling heat waste from production facilities back to the location of boilers and furnaces (Fig. 2). This strategy can result in reduced energy consumption in the creation of process heat. Depending on the building and applications, these heat-recovery investments can pay off in just a few years.
As for cooling, the energy required in many processes can account for upwards of 10% of electricity consumption. For this reason, even minor reductions can provide significant cost savings. Efficient cooling and chiller systems, however, require more than just efficient components. Plant-wide strategies must be created to integrate cooling with other utilities, often incorporating aspects of waste energy recovery.
To ensure cooling systems are operating as efficiently as possible, facilities should consider:
- Insulating pipes
- Making use of waste heat whenever feasible
- Minimizing system leaks
- Maintaining clean tanks and pipes to prevent efficiency-impacting deposit buildup
- Monitoring and analyzing process variables, such as density, to detect coolant aging early on
Fig. 2. Waste-heat recycling is a developing strategy to increase heating efficiency and reduce external resource consumption.
Boiler Efficiency and Steam Quality
Steam is one of the most essential utilities in process plants, providing the basis for heating, power generation and sterilization. Steam is generated via boiler systems of varying types and is then used directly in plant processes or to transfer heat at appropriate points via heat exchangers or direct consumption.
Today, the scope of steam management extends well beyond keeping boiler water level, conductivity, pH, temperature and pressure in check. Steam systems present numerous reduction, reuse and reclaimed energy opportunities through more efficient steam generation and distribution.
To keep boiler systems operating as efficiently as possible, plant personnel must judiciously monitor for leaks, particularly at valve bodies, pressure regulators, pipe connections and steam traps. In addition, steam quality must be measured directly in the pipe for all types, including wet, saturated and superheated steam.
In one facility, poor insulation, faulty steam traps and pressure and temperature variations resulted in the condensation of steam in the pipe, causing wet steam to form. This created poor energy transmission efficiency.
To address these issues, the facility made appropriate infrastructure improvements and installed multivariable vortex flowmeters throughout its steam system to identify the formation of wet steam in the early stages before it caused more significant problems (Fig. 3). This was made possible by the instruments’ ability to simultaneously measure mass flow, corrected volume flow, energy flow, temperature, pressure and dryness fraction, empowering users to monitor steam type in real time.
The flow meter was then configured to generate an alarm signal – passed to the central control system – when the steam content dropped below a pre-defined threshold, generally between 80-90%. With each percentage point below 100% corresponding directly with energy loss, improving the dryness fraction resulted in more energy available for the process.
Despite process variable fluctuations, the new flow meters provide high measurement accuracy for comprehensive energy management, even in compressible fluids like steam and gas. Additionally, mass flow measurement capabilities improve the accuracy of steam flow measurement compared to other flow meters.
Fig. 3. An industrial facility challenged with wet steam installed vortex flowmeters throughout the piping network to identify early warning signs of this issue, helping increase process efficiency.
As with all process improvements, informed decision-making for utilities begins with data from accurate and reliable measurements. These elements create the foundation for developing high-level energy management strategies.
Leading instrument manufacturers and process system suppliers can provide companies with the hardware and know-how to accurately measure processes at the right points, then analyze the resulting data to make appropriate operational adjustments. Companies can, thereby, achieve and effectively communicate organization-wide sustainability and emissions-reduction goals, empowered with continuous data collection and software for progress reporting.
Mark Thomas is the Oil and Gas Industry Manager for Endress+Hauser USA. Cory Marcon is the Power & Energy Industry Manager for Endress+Hauser USA. Endress+Hauser USA in Greenwood, Ind., can be reached at 888-363-7377, email@example.com or us.endress.com.
All images supplied by the authors.