This document summarizes a project at JEA, a large utility company, to reduce ammonia usage at their Northside Generating Station. A team identified that the controls were set up to spray ammonia unnecessarily, even when no emissions were being produced. They implemented a solution by reprogramming the pump logic and controller to stop ammonia flow when not needed. This achieved their goal of a 47% reduction in ammonia usage, saving $1.8 million annually while also providing environmental and safety benefits through reduced ammonia production and transportation. The changes were then replicated to the second unit.
1. Reduce Ammonia Usage In Circulating Fluidized Bed Boilers Team members: Mike D’Avico John Kang James Ragin Bob Lucas Allen Peterson John Wiseman Jessica Dotson Mike Davis Kai Wang Ron Beverly Mark Adams Dan Porter Chris Pruitt Ken Davis Black Belt: Jason Lankford
2. About JEA JEA is the largest community owned utility in Florida and the eighth largest municipal utility in the United States providing electricity, water and sewer service to more than 750,000 electric, water and sewer accounts in Jacksonville, Florida and parts of three adjacent counties. Annual revenues are about $1.2 billion. JEA is committed to our mission: “To improve the quality of life in the communities we serve by being the best electric, water and sewer utility in the nation.”
3. Process Improvement Mission and Goal Vision: Drive JEA to design and produce products/services to six sigma standards Goal: Use the tools and philosophy to produce products and services resulting in: Improved customer satisfaction and loyalty Reduced O&M and capital costs Improved work environment Initiated in 2000, our initiative has produced 35 Certified Six Sigma Black Belts and 270 Certified Green Belts Over 500 projects have been completed with over $125 million in bottom-line impact.
4. Why Ammonia? Project Background Ammonia is used to reduce Nitrogen Oxide emissions from electric generation systems. Continued operation of the generation fleet within environmental guidelines required that Nitrogen Oxide emission levels not be exceeded. Nitrogen Oxide emissions are marketable credits. JEA will not only meet, but will EXCEED all environmental requirements. Problem Statement: Ammonia prices have increased more than 30% over a nine month period, resulting in more than $34,000 in excess costs each month for ammonia at Northside Generating Station. Goal Statement: Increase Mega-watts produced for every gallon of ammonia used for NOx control from 1.7503 MW/gal by 10% to 1.92533 MW/gal by 2/1/09 without negatively impacting NOx rate. 4 Project completion has reduced consumption by 47% since February 2009, a hard savings of $1.8 million annually. That is over 1,000 tons of ammonia that does not have to be synthetically produced annually!
5. Introduction 5 In November of 2007, ammonia prices began a sudden and steep increase in prices. Ammonia is a commodity and prices tend to track with fuel costs. Cost as of 13-Oct-2008, $1100/ton Existing consumption at the new prices was depleting the annual budget for ammonia in months. Ammonia is required to keep air emissions within environmental limits. This project served to reduce consumption to a level that would allow the generation units to remain operational and within environmental compliance at all times.
6. Problem (Ammonia Usage) 6 Smog Nitrogen Oxides exposed to sunlight become smog Burning fuel creates Nitrogen Oxides (NOx) Ammonia reduces Nitrogen Oxide emissions. Nitrogen Dioxide in the lungs turns to acid; similar to pneumonia.
7. SIPOC Suppliers Process Outputs Customers Inputs Coal Air and solids mixed, combustion, treatment, exhaust Fuels Material Handling Bed Ash Pet Coke NH3 Supplier Fly Ash Ammonia AQCS Limestone Supplier Flue Gas Limestone Steam Heat Atmosphere Air Ammonia sprayed here NOx created here Process Steps Air, fuel, limestone mixed Combustion occurs Ash and flue gas out top of boiler Flue gas and fly ash continue to stack Ammonia sprayed into flue gas and ash Project Boundary Project Boundary 7
8. Existing Process 8 GOOD Effective use is determined by how many Mega-watt hours are generated per gallon of ammonia used (MWH/gal). Project goal of 1.925 shown in red above.
9. Cause Identification Because ammonia flows vary with nitrogen oxide production, the team had to look at both what causes nitrogen oxide formation and potential problems within the ammonia flow process. Using an XY matrix, the most probable causes were identified for analysis. 9
10. New Cause Identified 10 During flow testing, another item was identified. I have zero demand on the controller but I still have flow. That’s how the pump controller is set up. This is minimum flow. The AHA moment. The flow meter meets calibration, indications are correct. Our controls set up is currently causing us to spray ammonia into the boiler at 1.4 – 1.6 gallons per minute when no flow is required to meet emissions limits. We can make changes in the logic to reduce usage. We propose we are spraying needlessly!!
11. Solution Implementation To obtain a zero flow condition for a zero flow demand, the pump logic and controller were reprogrammed. Cost: under $5,000 Result: zero demand yields zero flow While control logic programming was being investigated, we also identified the capability to reduce consumption by controlling emissions over time instead of only instantaneously. This was also implemented to reduce ammonia usage. Initial expectations were to see the MWH/gal increase from the baseline of 1.7503 to 2.25 MWH/gal (27% reduction). After over six months of operation with the new control programming in place, we have realized a higher effectiveness than we previously expected at 2.57 MWH/gal. A 47% reduction in the volume of ammonia consumed. 11
12. Maintaining The Solution Full Automation Because implementation was fully automated, we have had to dedicate no additional resources to seeing it carried out on a constant basis. Our choice of implementation also reduced the number of items the control room operator has to watch on a constant basis. The operator is now free to improve other processes within the generation unit. A dashboard was created to visually track ammonia consumption, megawatt production, NOx rate, and MWH/gal. This dashboard is used by management and planning personnel to verify performance. 12 Visual Controls
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14. This is over 1,030 tons of pure ammonia.The energy and pollutant savings from this volume equates to over 4,000 megawatt hours of power generation! Financial Hard savings of $1.8 million resulting from programming changes. Soft savings of up to $200,000 based on reduced labor costs and suggested future improvements. Safety Fewer trucks hauling hazardous chemicals on: Local roadways In-plant roads Fewer unloading evolutions reduces the chances of inadvertent release of ammonia fumes. External Customer Satisfaction Reduced costs to the fuel fund results in less upward pressure on fuel rates. Team recognized by the CEO for their work towards JEA’s core mission statement.
15. Replication Programming changes were made to Unit 1 circulating Fluidized Bed Boiler at Northside Generating Station. Following initial testing, changes were fully replicated to Unit 2. Changes are discussed with outside companies during events such as Coal-Gen (a power generation convention series) 14 Potential replication to St. Johns River Power Park once new emissions equipment is installed and operational.
16. Updated Benefits Document 15 $1.8 million in hard savings along with the energy savings of removing 219 cars from the road annually