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Loretta Clevenger and Jerry Hassell

I n these uncertain eco- nomic times, most compa- nies are pursuing belt- tiglitening programs to reduce costs and improve cas1iJow. DuPont is no exception. Often, however. energy is overlooked as a key area that can signijkantly bolster the bottom line. With a total energy expenditurc of $1.5 billion a year, DuPont recently targeted its 25 most energy-intensive sites for an aggressive program to improve energy utilization perfor- mance. Within 120 days. adjustments in power and process areas at these sites yielded $1 2.5 million in savings.

IN i w E s E UNCERTAIN economic times, many companies are pursuing belt-tightening programs to reduce costs and improve cash flow-and DuPont is no exception. But, often, energy use is overlooked as a key factor that can significantly contribute to a company’s bottom line.

With a total energy expenditure of $1.5 billion a year, DuPont recently undertook an aggressive program to evaluate and improve its energy utilization performance as one way to achieve environmental and financial business objectives. The energy savings program, known as Jump Start, was launched in 1993 as an intensive four month search to find and implement low- or no-cost opportunities to realize immediate improvements in energy efficiency at 25 U.S.-based manu- facturing facilities.

The financial rewards far exceeded expectations. The program’s initial goal for energy-related cost savings was projected at $6.2 million. At the conclusion of the 120-day period, however, savings actually reached $12.5 million, more than double the initial goal. By continuing the Jump Start programs already in place and expanding the program to other facilities, DuPont expects to achieve savings of $30 million a year.

Setting the Agenda €or Jump Start Jump Start began as a 120-day “call to action” aimed primarily at

the company’s top 25 energy-intensive sites. I t was initiated to reduce the costs associated with the purchase and conversion of electricity and energy fuels such as natural gas, oil, and coal. The initiative was led by DuPont’s Corporate Energy Leadership Team (CELT), cam- posed of 43 members representing a cross-section of DuPont busi- nesses, functions, and energy-related disciplines worldwide. CELT is also directly linked with the Corporate Operations Network (a team from the manufacturing area) and the company’s Environmental Leadership Committee of the DuPont Safety, Health and Environ- ment Excellence Center.

Jump Start is also an outgrowth of two other important corporatewide

Loretta Cleuenger arid Jerry Hassell are ineinbcr-s of the Corporate Energy imdershqi Teain at The DuPoiit Cornpaizy it1 Wiltniiigtoii, Delaware.

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Loretta Clevenger and Jerry Nassell

A related objective was to

required little or no capital expendltu res.

focus OR pJ0jeCb that

initiatives at DuPont that reinforce the company’s recognition of the environmental and bottom-line benefits of excellence in energy manage- ment. In 1992, the company adopted a corporate energy policy. The policy focuses on three areas: (1) reduction of the environmental impact of energy emissions, (2) increased efficiency of energy use, and (3) renewal of the power infrastructure. These commitments are being vigorously pursued through a partnership between business and opera- tions leadership, with CELT playing a key role.

In addition, a corporate Energy 2000 strategy defines the steps that must be taken to improve energy utilization (as measured in BTUs per pound of finished product) companywide by the year 2000. The reduction of emissions and competitive sourcing and generation of energy are also part of the strategy.

To begin, CELTdeveloped a strategic plan to address the company’s business objectives. From this initial meeting, a workingteam evolved that consisted of CELT representatives, energy engineering consult- ants, and power engineeringoperations personnel who were assigned specific duties to communicate and implement the plan at each site.

The Energy Tool Box The intent of Jump Start was to initially focus on those operations

and processes where the largest potential savings could be achieved in the shortest amount of time (i.e., the low-hanging fruit). A related objective was to focus on projects that required little or no capital expenditures. These included programs for energy-eficient lighting, steam trap and steam header maintenance, turning off equipment and lights not in use, boiler and burner efficiency improvements, insulation maintenance and repair improvements, fuel inventory reductions, and fuel purchase savings.

To assist the energy teams responsible for evaluations at each site, an “Energy Tool Box of Best Practices” was developed that provides general guidance (recommendations are modified according to the size of the plant and complexity of the processes) on best practices and prime opportunities to improve energy efficiency. The key tools are described in the sections that follow.

Walk-through energy survey This survey can be conducted by a team of two to four people,

spending one to two days walking through the process, while plant personnel describe the manufacturing steps. For best results, the team should include an engineer familiar with energy systems and plant personnel who know the process well enough to anticipate the effects of possible changes. Electrical experts provide a critical view of electrical distribution and demand control issues, and any other changes that could affect electrical use. At DuPont, the Energy Engineering group, an internal staff of engineers with the expertise to identify low or no capital operational improvements, worked with sit,e operational personnel to conduct these surveys.

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A walk-through survey can identify a wide range of energy-saving opportunities. (See “Rules of Thumb,” quick methods of evaluating these opportunities.) Some may be as simple as shutting down spare pumps or fans. Others, such as process energy balances, require further study.

Energy conservation checklists are also used to help generate ideas for improvements in a variety of process and power areas. (See checklist on page 309). Savings items are documented and briefly discussed during the walk-through to determine feasibility, risk, and a rough estimate of costs. After the survey is complete, the team lists and reviews ideas in more detail, rejecting those with poor payback or high risk, and develops a plan for the ideas with the greatest potential. In general, this exercise should result in a 1-to-5 percent reduction in the cost of purchased energy.

Comprehensive site energy survey A comprehensive energy conservation survey can identify signifi-

cant savings from operating changes (low or no capital) and from process changes requiring new equipment. This type of study involves much more detail and time than a walk-through survey, but it has the potential to realize much larger savings.

It is recommended that a three- to six-person technical team spend three to six months conducting the survey. The team should include plant process, utilities, and electrical personnel as well as a person familiar with a wide range of energy systems, such as an energy engineering consultant.

Before starting a comprehensive survey, the team responsible must define its methodology. This includes how the team will func- tion administratively (choosing a leader, etc.), how often the team will meet, scheduling, areas to be included in the study, and assign- ment of area responsibility. The team must also agree on cost or value of utilities to be used in calculating savings.

The actual survey begins with team members reviewing process flowsheets, including the mass flows, temperatures, and pressures throughout the process. This provides a clear understanding of the total process and identifies possible opportunities for heat recovery, process changes, or different uses of existing utilities. The powerhouse utilities area is also reviewed for energy-efficient design and operation.

As energy conservation ideas are generated, they are discussed by team members to develop and implement strategy and to define the effects of revisions on operations, design, risks, and economics. The overall financial goal, which varies by plant and process, typically is to reduce purchased energy costs by 5 to 10 percent. The impact on emissions from combustion include reductions in carbon dioxide (CO,), nitrous oxide (NOx), and sulfur dioxide (SO,).

The use of PINCH technology should be considered depending on the complexity and size of the process. PINCH technology is a technique used to analyze and optimize total energy systems. I t takes

The overall financial goal...typicallg is to reduce purchased energy costs by 5 to 10 percent.

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Energy Efficiency Rules of Thumb Rules of thumb are quick methods of evaluating opportunities that

should be used in conjunction with walk-through surveys, suggestions by others, and as a basis to make baseline evaluations to determine feasibility and/or cost benefit. These rules can be used as a stimulus to develop more specific rules of thumb a t individual sites based on fuel and electric costs. Rules are grouped by utility and are by no means inclusive. Some examples follow. (Many other rules of thumb, as well as algorithms, data sets, etc., can be used to make first level appraisals of energy conservation opportunities.)

Compressed air (assunte $O.S/Kw?i average cost) 100 psig air cost $.15 per 1,000 cubic feet. 100 cfm of air a t 100 psi cost $8,000 per year. 100 psi air leaking through 1/8 inch hole cost $2000 per year. Reducing pressure by 10 psi will reduce cost 5 percent.

range

its name from its identification of a key system temperature con- straint, or PINCH, which thermodynamically limits heat recovery and thermal energy efficiency. The use of the procedure helps to (1) identify and set energy and capital targets; (2) design heat recovery networks that meet those targets; (3) develop procedures for retrofit- ting and new design; (4) design a utility system to match the process; and (5) modify the process to improve targets.

A PINCH analysis of a single product on a plant site can run as low as $15,000, whereas a multiproduct study at a site can run above $200,000. Cost is also determined by the level of detail in the analysis and complexity of the process. Analyses of process systems using

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Case Study: From Jump Start to Nigh Gear-How DuPont Is Cutting Costs by Boosting Energy Eflciency

Cooling towers (continued) Windage/drifdO,l percent-0.3 percent of circulation rate Blowdown-2.5 percent to 3 percent of circulation rate

Cooling tower flow is approximately 3 gpm per ton cooling. Tower size is sensitive to temperature change ( O F ) between exit and wet bulb:

Change in temperature ( O F ) 5 15 25 Size scale relative volume 2.4 1.0 0.5

Counter current mechanical towers are able to cool within 2" F of wet bulb.

BoilersJContbustion Energy saving by boiler improvements are:

Boiler operation sequence control 2 percent 1 percent Automatic boiler blowdown

Automatic 0, trim 2-3 percent Low excess air burner 2-3 percent

3 percent 1-3 percent

densate saved and returned to the boiler saves $7,500 per generated @ $4.00 milliofltu. 1 in flue gas temperature is equivalent to a 1 percent

nge in flue gas 0, is equivaIent to a 10 percent efficiency

psi steam to 10 psi condensate is 18 percent, from 125 psi i condensate is 12 percent.

d per 1,000 cfm is 120 to 200 million Btu per year.

nomizer will save $150-225 per year per 1,000 cfni of

tion savings thermostat is 3 to 6 percent of load, for 5 to 10 percent of load.

PINCH technology have shown energy savings from 15 to 40 percent of existing energy use.

Steam Trap Program Steam traps are mechanical control devices used to remove con-

densate arid noncondensate from steam systems and equipment. They are found on steam generation and distribution piping systems, steam tracing systems, heating and ventilation systems, and numer- ous process equipment applications. More than 150,000 steam traps exist at DuPont's U.S. Chemicals and Specialties sites. The top 25 energy-consuming sites average 4,000 steam traps per site.

.~ ~

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Loretta Clevenger and Jerry Hassell --

Unfortunately, mechanical devices like steam traps can fail, Depending on the mode of failure and application, steam trap failure results in energy loss, additional emissions, steam systemkquipment operating problems, and process control or process heat transfer problems. The stake is estimated at $17.5 million in energy expendi- tures. An effective steam trap program will have a positive impact on the environment by reducing air emissions due to lower consumption of fuel oil, natural gas, and coal.

Given the number of steam traps and the potential magnitude of environmental and economic losses from their failure, DuPont has recommended that their sites have an organized steam trap manage- ment program in place. Sites with effective steam trap programs typically have the following elements:

An effective steam trap program will haue a positive impact on the environment by reducing air emissio ns...

An individual in the power area, manufacturing area, or a predictive maintenance group who is responsible for ensuring that steam trap testing and maintenance are performed in a timely manner. Personnel who perform area/site-specific steam trap testing and timely maintenance. The number of people involved in this process (from two to five people at a site with 4,000 steam traps) is a function of the actual number of steam traps, population size, system condition, and degree of program automation. Training for personnel responsible for trap testing and main- tenance. Steam trap testing equipment and computer hardware/soft- ware to analyze test results, computer costs and savings, link with the site procurement system, and report trap mainte- nance results. Standardized site steam trap models and installations.

Energy-efficient lighting program Lighting represents 9 percent of the total electrical energy con-

sumption at plant sites and 40 percent in offices. New technological advances in the manufacture of fluorescent lamps and electronic ballasts have made it possible to save more than 35 percent of lighting energy currently used without decreasing its quality and in the process achieve substantial cost reductions and reduced air emis- sions. For DuPont, more efficient use of lighting could reduce costs by an estimated $12 to 14 million a year on a corporatewide basis.

To help sites develop their own energy efficient lighting pro- grams, a corporate lighting task force conducted a study that included the following information:

* Recommended approaches and materials An analysis of potential energy-saving methods

A case study from the Wilmington area offices

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! Case Study: From Jump Start to High Gear-How DuPont Is Cutting Costs by Boosting Energy Emciency

Environmental considerations Implementation guidelines Financial analysis for retrofit

The report includes a diskette containing a Lotus-based spread- sheet that enables users to input data on the numbers and types of lighting fixtures. The spreadsheet can then be used to perform financial calculations of fluorescent lighting efficiency improvements based on individual site conditions such as energy prices, material and labor costs, taxes, utility rebates, operating hours, and so on.

Combustion efficiency improvements Improvements in combustion efficiency can yield substantial

savings in fuel costs and product quality. Fuel savings are realized when the fuel-to-air ratio achieves the maximum heat transfer pos- sible. The heat available from the fuel is a variable and function of excess air, combustion temperature, fuel type, and combustor design. Assuming a 2000°F combustion temperature, the heat available for transfer with No. 6 oil at 25 percent excess air is about 38 percent, whereas with 50 percent excess air, it is about 30 percent. Using this example for a boiler heaterlapplication with a requirement for trans- ferring 100 million Btu per hour and current No. 6 fuel oil prices (at $15.50), firing with 25 percent versus 50 percent excess air could result in yearly savings of more than $180,000 a year at a 95 percent utility. Similar savings potential exists for all types of fuels.

With regard to product quality, savings are product-specific and must be estimated individually. For example, ore roaster kiIns are usually set up to provide the desired ore residence time and exit temperature, which may necessitate excess air levels greater than required for high-efficiency combustion.

To improve the efficiency of any combustion process, the burner/ combustion element must be periodically tuned. (Tune-up is preceded by a good material inspection, and cleaning and repairs when re- quired.) The actual tune-up consists of setting the optimum fuel-to- air ratio over the range of operation for the specific combustion process. As noted above, for some of the processes, the optimum fuel- to-air ratio requires excess air levels above those necessary for good combustion.

The tune-up begins by applying a good quality, calibrated portable flue gas monitor to establish the conditions of the operating combus- tion process relative to its excess oxygen and carbon monoxide levels. Adjustments in the amount of fuel or air required are then made to ensure stable and safe operation. Starting with the low-fire setting, the optimum fuel/air ratio is set. In reasonable increments, this is repeated until the high-fire setting is reached. The adjustment pa- rameters are the relationships among the excess oxygen level, carbon monoxide concentration, and load.

The typical burnerhombustor needs a t least two tune-ups a year,

Fuel savings are realized when thefuel-to-air ratio achieves the maximum heat transfer possible.

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Loretta Clevenger and Jerry Hassell

requiring a total of eight hours per burner/combustor and two hours to write the report. Personnel required include one well-trained energy consultant and a plant operator.

Most burners/combustors use 10 to 25 percent excess air above the optimum level. On an annualized basis, this equates to an overall savings for DuPont’s U.S. Chemicals and Specialties of $5 to $20 million. From an environmental perspective, keeping burnerslcom- bustors properly tuned can contribute as much as 10 to 15 percent reduction in NOx emissions. The principal source of thermal NOx is the oxidation of nitrogen contained in excess air.

-- - ... keeping burners/

. combustorsproper~y tuned can contribute as much as 10 to 15 percent reduction In NOx emfssions.

Electrical peak shaving Electrical costs are divided into two major parts: (i) capacity

charge as measured by peak load per kilowatt, and (2) energy charges per kilowatt hour that generally equal fuel charges. Peak shaving programs, managed by knowledgeable engineers on-site and local utility sales representatives, control the peak load by determining acceptable load fluctuation and avoiding unmanaged peaks. Peak load management can take several forms:

Delaying start-up of equipment to prevent a new peak; Using alternate standby generation equipment at peak times; Shifting load from peak times of day to off-peak times of day; and Shutting down equipment (such as air conditioning or light- ing) to avoid setting a peak.

*

To make these decisions, a peak shavingprogram must include an on-line data system to provide current information.

Electrical contract optimization The optimum electrical contract provides the most economical

mix of electricity to the site, with reasonable risk taking according to the serving utility and the specific needs of the site. Potential savings are estimated a t 5 percent of corporate electricity purchased. The contract should consider the following factors:

Historical peak load Expected peak load Availability of interruptible service (i.e., choosing from a vari- ety of interruptible services if available) Minimum billing (contract take or pay) Owning substation-pay lower transmission rates *

To develop the optimum contract, a site analysis of electrical requirements on an hour-by-hour basis for a representative period is needed, along with utility data provided by sales representatives and plant meetings with the energy buyer and utility personnel.

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Case Study: From Jump Start to High Gear-How DuPont Is Cutting Costs by Boosting Energy Enciency

... a site analysis of electrical require men ts on an hour-by-hour basis for a representative period is needed ...

Energy conservation checklist A DuPont Energy Conservation Checklist is an evergreen check-

list that was produced in a booklet containing more than 200 tips on how to reduce energy costs. The booklet is written in a series of “one- liners” that serve as reminders of the possibilities, and it is designed to be carried by members of energy survey teams as they observe the plant. No explicit detail is offered, and not all items are applicable in every plant. The booklet contains sections on

Steam or down-therm generation Steam users Electrical loads Electrical distribution Refrigeration Cooling towers Heating ventilation and air conditioning (HVAC) Compressed air Fans Pumps Building energy services Miscellaneous (e.g., wastewater treatment and chemical sam- pling systems)

It is reasonable to assume that a 5-percent reduction in plant energy cost could be achieved using this checklist to identify opportu- nities. An initial review requires about 8 to 10 hours.

Building automation systems One of the major expenses in operating a building is the cost of

energy required for heating and air conditioning the space. Depend- ing on the building and W A C systems, the heatinghooling cost may constitute from 25 to 40 percent of the operating cost of the building. (A recent survey indicates that DuPont spends an average of $6 to 10 million a year on various types of HVAC temperature control systems.)

A Building Automation System (BAS) is a computer-based hard- ware and software system that monitors, controls, and reports on the performance of W A C systems and the building environment, based on the information sensed throughout the building(s) and control software selected by the user. A BAS provides several advantages over conventional pneumatic control systems:

0 Operation of W A C equipment is optimized, reducing energy consumption. Greater reliability and lower maintenance. Data are available for improved facility management. Energy management control strategies are readily imple- mented.

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Exhibit 1. DuPont Jump Start Program's Savings by Site (in thousands of dollars)*

Location of Site Savings Location of Site Savings

Bayport ('E) Beaumont (TX) Belle CWV) Brevard (NC) Camden (SC) Cape Fear (NC) Chambers Works (NJ) Chattanooga (TN) Circleville (OH) Cooper River (SC) Delisle (MS) DuPont Canada Experimental Station (DE) Florence (SC) Front Royal (VA) Kinston (NC)

38 1259 590 152 118 523

1829 156 67

202 164 600 267 278 102 168

Laporte (TX) Louisville (KY) Martinsville Memphis (TN) New Johnsonville (TN) Niagara (NY) Old Hickory (TN) Ponchartrain (LA) Sabine (TX) Seaford (DE) Spruance (VA) Washington Works (WV) Waynesboro (NC) Victoria (TX) Yerkes (NY)

93 1 318 328 370 428

14 110 525 682 292 248 418 483 764 112

"Total savings is $12.5 million, annualized at $31 million, excluding one-time cash savings.

A key assignment of the BAS is to reduce energy costs as much as possible, typically 10 to 25 percent.

Jump Start Success Stories During the first 120 days, the 25 target sites for Jump Start

achieved energy savings of $12.5 million. Savings at individual sites are listed in Exhibit 1. Exhibit 2 shows the percentage of total savings resulting from specific energy conservation measures. Below are some highlights of site successes.

At DuPont Canada's Kingston site, a team effort led to the detection and repair of compressed air leaks in all of the operating areas. More than 500 air leaks have been identified, and half of them have been repaired so far. This has saved more than lOO(kW) of electrical energy, with the potential for savings of 1,000 kW or about $340,000 (Canadian) a year in reduced electrical costs.

The wastewater treatment plant at DuPont's Chambers Works in Deepwater, New Jersey, consumes more electricity than any other on- site project. As part of the Jump Start program, a team representing operations, maintenance, and R&D was successful in reducing the number of blowers during nonpeak periods and refitting motors,

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Case Study: From Jump Start to High Gear-How Dflont Is Cutting Costs by Boosting Energy EJicierwy

Exhibit 2. Jump Start Energy Efficiency Improvements: Percentage of Total Savings by General Category

Share of Total Cost Savings

category (Percent)

Shut down of spare or unneeded equipment 26 19

Renegotiation of fuel, electricity and service contracts 19 Waste heat and condensate return 8 Electrical peak management 6

Tune up and optimization of systems and processes

Fuels inventory reduction 5 W A C system management improvements 5 Improved steam trap maintenance program System or process improvements 5 Elimination of leaks and vents

5

2

which achieved increased electrical efficiencies that will result in cost savings of about $500,000 a year.

The Bayport, Texas, site was one of six sites not initially targeted by Jump Start that has voluntarily joined the effort. A team at this plant implemented a system to track the amount of nitrogen and electricity used in the manufacture of “Kapton” polyimide film. As a result, Bayport was able to reduce its consumption by 2 1 percent per pound of manufactured product.

An energy conservation team at DuPont’s Facilities Services was formed to find ways to trim its $25 million annual utility bills. At one site, the DuPont Experimental Station Laboratory in Wilmington, Delaware, cost savings of $267,000 were achieved on an annual energy bill of more than $9.3 million through peak shaving, tempera- ture standardization (during the day and off hours), and by turning off or down unnecessary lighting and equipment.

Jump Start’s initial success and growing employee awareness have inspired seven additional sites that were not among the original 25 to voluntarily join the program-and the list continues to grow. Recently, a similar program has been launched at DuPont’s sites in Europe.

Keeping the Spirit Alive For the long term, the intent is to keep the Jump Start spirit alive

by continuing to build commitment and enthusiasm. More emphasis will be placed on integrating the energy strategy into the businesses of DuPont and identifying new opportunities and additional re-

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sources. Programs aimed at heightening awareness of Jump Start’s successes, and the tools for action it provides, are critical to this process. By sustaining the support for programs in place and continu- ously searching for new ones, energy conservation has become more than a possibility-it is a reality. +

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