Energy Efficiency Opportunity Assessment Tool

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Instructions Opportunity Estimator

The chemical and refining industries are primarily continuous processes that ar

optimized for maximum production. It is well known that during times of low d

become less energy efficient. Due to historically low fuel prices and the uncerta

duration of low demand periods, energy efficiency at low demand operating co

given much consideration.

With the escalation of energy prices in the last 5-10 years along with extended

and thin profit margins, improving a plant's operating energy effiency is a succ

to increase profitability and gain a competitive edge!

This tool was developed for plant owners, operators and energy managers. The

information to help plants improve their energy efficiency in general, with a sp

opportunities that can be realized during periods of low demand. It is a collecti

the DOE, general industry literature, academia and industry experts. It is comp

helps direct the user to specific information related to energy-efficiency opport

Energy-Efficiency Opportunity Assessment Tool

Plants and Refineries Running at Low Utiliza


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e designed and

mand these operations

inty associated with the

ditions has not been

periods of low demand

ssful and proven way

tool provides basic

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ion Rates


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Energy Management Program AnswerDoes the plant have an on-site Energy Leader? noAre energy efficiency targets established for operating at low utilization rates? no

Is progress towards energy efficiency targets measured, trended and reported? no

Are there corporate goals for energy efficiency? no

Recommendations

Site Operational Practices AnswerWhat is the current utilization rate compared to full-load design operations?


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Leadership1 Each site should have an Energy Leader. This should be an empowered leader that has the support of site management.

In the case of a large site with many production units, it is helpful to have a designated energy focal point at the

individual unit level.

2 Each site should have an active, cross-functional energy team directing the site energy program.

3 There should be a site Energy Champion that is also a member of upper management. His/Her role is to support the

energy program and promote energy efficiency in all aspects of site operations.

Metrics and Targets1 As a minimum, energy intensity (EI) should be tracked as a measure of energy efficiency at the site or plant. EI is the

energy used per unit of production, and is usually expressed as BTU per lb. It should include all forms of energy used at

the plant.

2 Conduct benchmarking studies to compare the plant's energy efficiency to that of other units or plants in the company or

industry.

3 Establish targets for energy efficiency during times of low utilization. Progress towards these targets should be measured,

trended and reported.

4 In addition to site level targets, corporate energy goals should be established.

Energy Metrics and KPIs1 Energy Metrics and Key Process Indicators (KPIs) should be displayed on dashboards, visible to operators. These KPIs

should include energy users that have been picked as energy reduction focus areas. For example, CTW pumps, fans,

compressors, etc.

2 There should be training and expectations for operators to utilize dashboards to monitor and manage plant energy

efficiency.

Energy Projects1 Review energy project lists to determine if a previously identified project is now feasible during times of low production

demand.

Energy Management Program Section


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Matching Generation with Consumers via Production Scheduling1 Match fuel gas producers with fuel gas consumers through production planning and optimization.

2 Match steam and waste heat producers with consumers through production planning and optimization.

Multiple Unit, Site, or Train Optimization

1 Dual trains should be optimized so that minimum energy is being used. Procedures should be developed and used forthis optimization operation.

2 There is a need to rationalize production when making the same product at multiple sites and demand is low. The

business may need to consolidate production to fewer sites.

3 Multiple equipment (furnaces, boilers, compressors, etc.) should be base loaded properly, i.e. most efficient

equipment run at highest rates.

4 Monitor Turbo machinery efficiency for optimizing their operations.

Optimization Tools for Furnaces, Heaters, Boilers, etc.1

Optimize furnace efficiency around stack O2 percent. With proper controls, alarms and trips, the target should be to

achieve O2 below 3% and operate in a safe manner at the desired firing rate. Determine the O2 point (by field testing)

at which the heater runs out of air (CO breakthrough) and set the operating O2 target at ~0.5% above that point. This is

a big opportunity in refineries where there are a lot of furnaces and heaters. However, at extreme turndown conditions

a heater may run at 8%-10% O2 with the stack damper at minimum stop and the air registers almost closed.

2 Evaluate and install turndown capabilities for fired equipment, including furnaces, heaters, boilers, etc., to maximize

efficiency at lower rates and eliminate startup/shutdown losses.

3 Include refinery heater efficiency as part of site or plant reporting. For example, highlight the 5 best and 5 worst

heaters, along with opportunity gaps.

Production Scheduling1 Evaluate reducing the number of shifts or days of production to decrease fixed energy consumption.

Develop Turndown Operating Discipline1 Develop and document turndown scenarios for each unit.

2 Develop monitoring guidelines for running at reduced rates to ensure the plant is at it's optimum.

3 Procedures for operating at low rates should include appropriate discipline, checklist, etc. for upstream anddownstream units.

4 Develop operating discipline for keeping units on hot standby. For example, how long should a boiler or other fired

equipment be kept on line with little or no load?

Variable Frequency Drive Applications1 Turn off circulation/transfer pumps when not in use.

2 Use variable frequency drives on appropriate centrifugal compressors or pumps that would otherwise run at constant

speed and/or recycle at low rates.

3 Evaluate cooling tower water and process pumps for VFD application.

4 Evaluate cooling tower fans and fin-fan heat exchangers for VFD application.

5 Evaluate boiler and furnace fans for VFD application.

Site Operational Practices Section


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Distillation1 Circulation in absorber-stripper systems is often fixed and independent of rates. Evaluate reducing circulation during

times of low production.

2 As rates are lowered, product purity can exceed specifications. Bring product purity back to specifications, thereby

reducing column reflux and reboiler duty.

3 If reflux is in flow control and independent of column feed rate, the reflux ratio will increase as feed rates are

lowered. Consider modifying column control to maintain constant reflux ratio when feed rates change.

4 Consider upgrading the control system to automatic control with an economic payout and subsequent savings in energyrequirements.

5Consider the use of vacuum pumps or steam ejectors to balance steam loads, depending on site steam balance.

6 Develop operating discipline to determine reflux ratio vs rates for processing multiple feedstocks.

7 Consider advanced computational modeling techniques for distillation control to save energy.

Maintenance & Utilities1 Use predictive maintenance vs planned preventive maintenance for optimum process cleaning intervals, especially for

exchangers. Operation at lower rates may allow for longer maintenance intervals.

2 Use low demand periods to shut down and clean process equipment that will improve energy efficiency.

3 Minimize utility losses (Steam leaks, steam trap losses, compressed air losses, etc.) by conducting regular assessments

and having BestPractices management programs for them.

Batch Operations1 Focus on scheduling, and minimizing fixed energy usage like recovery systems, utility supplies, i.e. boilers, support

systems, recovery systems, heaters, etc.

Process Cooling & Facilities Energy Management Systems1

Optimize chiller plants and refrigeration units which are used for industrial process cooling and building HVAC.

2 Incorporate building energy management systems to save energy in office buildings and industrial facilities. This would

reduce energy consumption during periods of low occupancy and plant shutdowns.

Miscellaneous (driven by economics vs EE)1

When generating steam at low rates, consider purchasing steam from a third party when economically feasible.

2 Consider converting products with low demand into products that are in high demand, i.e. convert acetylene to

ethylene.

3 Consider fuel switching and renegotiation of contracts to take advantage of operation at lower rates.

4 Utilize contract manufacturing to reduce energy demand at under-utilized facilities.

5 As rates are lowered, reduce heat exchanger flow to maintain delta T, and maintain efficiency.

6Solids drying - at low rates increase dryer speed and/or turn down air flow to keep from over drying product.


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Operator Knowledge and Engagement1 Foremen and operators should be sufficiently skilled and trained to incorporate energy conservation techniques in their

job duties.

2 Empower operators to act as 24-hr energy managers in the plant.

3 Ensure that systems are in place and operators are trained sufficiently to optimize Actual vs. Target energy metrics on

a daily basis.4 Reward and recognition plans should be in place to encourage employee engagement at all levels in energy efficiency

activities.

General Energy Efficiency Culture1 Address the total energy efficiency culture at the site. Encourage all employees to turn off equipment when not in use.

This includes lights, fans, pumps, etc. This also includes equipment in office buildings. Everyone should know what they

can do to save energy.

How to find Opportunities1 Perform an assessment to identify opportunties during times of low utilization. This assessment could include a review

of the Mass & Energy Balance flowsheets for opportunities, brainstorming sessions, audits of specific systems, etc. Add

opportunities to the plant project list for prioritization and implementation.

Understanding the Plant Energy Usage1 Understand the plant's energy footprint - fixed and variable process loads.

2 Evaluate the plant's energy efficiency vs state-of-the-art or some other benchmark, at low utilization. Quantify this gap

and compare it at full rates. The gap at low rates should not be greater than the gap at full rates.

3 Establish targets for energy efficiency during times of low utilization.

Energy Efficiency Knowledge and Training Section


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Opportunity messages are based on the category scores and overall score.

This tool does not evaluate your system specific technological potential for energy savings. Please refer to the US DOE ITP BestPractices Tools that a

broader question of technological improvement. System specific energy assessments will identify true technological opportunities.

How does the tool work?

Yes or no answers to questions score points if the answer indicates an energy savings practice. Questions are weighted with factors of 1, 2, or 3.

Multiple choice questions score -1, 0, or 1

If your version of Excel doesn't default to autocalculate, then please hit the "F9" key for calculating.

To learn more about a specific question or area, click on the "to topic" link next to the answer for that question.

The tool also calculates an overall color-coded opportuntiy score at the bottom of the page.

How to use this tool?

Go to the tool tab directly, or click on the link on the Introduction sheet

Answer the questions under the three general categories; 1) Energy Management Program, 2) Site Operational Practices, and 3) EE knowledge and Tra

The tool calculates a color-coded opportuntiy rating at the bottom of each general category section.

To learn more about improving efficiency in one of the three general categories, click on the title link at the top of the general category section.


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Energy Efficiency Opportunity Assessment Tool

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