ESA-021-2 CEMEX Inc. - Victorville Facility
Final Public Report
Introduction: CEMEX Inc. is the largest cement and ready mix company in the United States. In the United States alone, CEMEX Inc. has 12 cement plants, close to 50 distribution terminals, over 300 ready-mix plants and approximately 50 construction aggregates quarries. The United States Department of Energy (DOE) “Save Energy Now” program completed an Energy Savings Assessment (ESA) May 8, 2007 at the CEMEX Inc. facility in Victorville, California. The DOE Qualified Specialist/Energy Expert conducting the compressed air system ESA was Kyle Harris of Accurate Air Engineering, Inc., Bakersfield, California. The CEMEX, Victorville facility consists of two locations, the “River Plant” and the “Quarry Plant”. The compressed air ESA was performed at the “River Plant” that includes eleven rotary-screw air compressors operating in “satellite” locations serving a number of different end uses. The air compressors vary in size from 50 horsepower to 200 horsepower. The plant uses compressed air on a 52 week per year, 7 days a week, 24 hours per day schedule. Currently, the compressed air system uses 5,233,463 kWh/year. Objective of ESA: Identify compressed air system improvement recommendations, train plant personnel how to correctly model the current system and predict potential savings using the DOE AIRMaster+ software tool. Focus of Assessment: Compressed air supply, distribution and end uses. Approach for ESA: Amp data was collected on all eleven air compressors for a period of seven days. Together, the DOE ESA Expert and plant personnel used LogTool V2 to interpret the data and format the data for direct import into AIRMaster+. Compressor profiles were developed and a baseline compressed air profile was created within AIRMaster+. A survey of the compressed air supply and demand was completed. As part of the “training assessment” the plant personnel, with direction from the DOE ESA Expert, created a number of energy efficient measures to evaluate the impacts of each measure. Ultimately, these measures were prioritized in order to achieve the best effect of the improvements. A closeout meeting was conducted to present the findings to a number of plant personnel that may be affected by the proposed improvements. General Observations of Potential Opportunities: The following section briefly discusses the projects identified for additional investigation or implementation. A qualifier is assigned to each project – near-term, medium-term or long-term. These descriptors are identified as follows: Near-term opportunities would include actions that could be taken as improvements in operating practices, maintenance of equipment or relatively low cost actions or equipment purchases. Medium-term opportunities would require purchase of additional equipment and/or changes in the system. It would be necessary to carryout further engineering and return on investment analysis. Long-term opportunities would require testing of new technology and confirmation of performance of these technologies under the plant operating conditions with economic justification to meet the corporate investment criteria. Near-Term Opportunities
Shut Down Two Air Compressors Currently, out of the eleven air compressors operating at the “River Plant”, two contributed little to no compressed air to the system during the entire on week of data logging or during the ESA. The “JBH1C”, 50 horsepower modulating air compressor and the “KC6”, 75 horsepower modulating air compressor operated
ESA-021-2 Public Report
together at an average 60 kW while only supplying an average 30 cfm to the system. The 50 hp air compressor modulates only and does not blow down, while the 75 hp air compressor remained blown down for the entire week but does not time out. At a minimum, these air compressors should be turned off allowing the other nine, modulating air compressors to pick up the load. It is also possible to equip the 50 hp air compressor with blow down and auto-start/timed-stop controls and inquire about the ability of the 75 hp air compressor to time out when blown down. Depending on the solution chosen, little to no initial investment is required for this opportunity. It is estimated that over 300,000 kWh or $25,000 annually could be saved with a payback of less than 0.2 years. Medium-Term Opportunities
Automate Air Compressors During the pre-ESA data logging and subsequent modeling in AIRMaster+, at least 10 out of the eleven air compressors operated in some state of modulation or part-load. Even after shutting down the “JBH1C” air compressor and the “KC6” air compressor, it is highly likely that most of the remaining air compressors will operate modulated most of the time. It is recommended that the air compressors be automated so that an air compressor is 100% loaded or off with one air compressor loading and unloading. Preferably, most of the air compressors would be moved to a more central location where automation would be more effective with better control. All current assets may be used to keep the initial project cost lower, but with more analysis new “base load” air compressors are an option. It is estimated that over 1 million kWh or $140,000 annually could be saved with a payback ranging from 0.55 years to 1.4 years depending on the final arrangement. Reduce Air Leaks Most of the piping in this facility is underground and twenty to fifty years old. Though not confirmed, there may be some underground piping that was installed in the early 1900’s when the plant was first built. Many areas in the plant bubble through the concrete when it rains; areas where it is suspected that the main compressed air piping is located. It is estimated that a least 250 cfm of air leaks could be corrected if the underground pipe was replaced but this figure could go as high as 750 cfm of air leaks. Future testing would attempt to isolate areas of the underground piping, test the leak loads and reevaluate the savings and return on investment. It is estimated that a minimum of 298,000 kWh or $25,000 annually could be saved with a payback less than 4.0 years.
Long-Term Opportunities
Improve End Use Efficiency There are many open-blowing applications at this plant. The areas of higher concern are the “air horns”, used to cool off gear boxes and motors as well as open air lines to “fluff” the product in silos. In some “air horn” applications, the gear box is water-cooled but the heat exchanger performance is not adequate. Most of these open-blowing applications are left on (valve open) regardless of the need. At a minimum, these applications should be automated so that the air is only used when absolutely necessary. It is estimated that a minimum of 372,466 kWh or $31,000 annually could be saved if 250 cfm of compressed air in these applications were replaced with comparable technologies using electric motors. Paybacks could be as low as 0.3 years.
Management Support and Comments: Cemex, Inc. is dedicated to reducing energy consumption throughout its plants worldwide. Brodie Pederson, production manager, provided support prior to the ESA commencing. Both the site lead, Rajat Sekhon and team member, Albert Padilla provided full support during and after the ESA. They are dedicated to improve the compressed air system at the Victorville “River Plant”. Immediate plans also include using this ESA to move forward with an evaluation of the compressed air system at the Victorville “Quarry Plant”. DOE Contact at Plant/Company: Rajat Sekhon, PID, Cemex, Inc.
16888 N. “E” Street Victorville, CA 92394
(510) 688-8081 Rajat.sekhon@cemex.com
ESA-021-2 Public Report