Ohio Energy Workshop HH Strategies & Technologies to Improve the Boiler Room Efficiency Wednesday, February 21, 2018 2 p.m. to 3:15 p.m.
Biographical Information Jon Green, Mechanical Equip. Consultant - Central & Northern Ohio Lathrop Trotter Co., 5098 Oaklawn Dr., Cincinnati, OH 45227 513-478-7288 jon.green@lathroptrotter.com Jon has been in engineered systems sales for 11 years. He spent the first part of his career in air pollution control technologies. As a regional manager of business development, he developed and grew the CECO Energy Management Team, where he focused on energy management in industrial ventilation systems. Working with manufacturing plants, he was responsible for reviewing the process air systems, identifying energy losses, and presenting an economic analysis and design for decreasing fan HP and compressed air usage. For the past 6 years, he has focused on boiler room systems and combined heat and power, including efficiency improvements and retrofits. As a factory representative for various boiler and turbine technologies and ancillary items, he has a unique view of how to apply the best engineering and equipment for steam and on-site power systems. His projects are mostly with manufacturers, hospitals, and institutional facilities helping consulting engineers and energy managers with technology selection and economic analysis to develop and validate energy projects. Jon is a graduate of Miami University (Ohio) with a B.S. in Business-Economics. Jon Schroeder, PE, Sales Engineer - Southern Ohio Lathrop Trotter Co., 5098 Oaklawn Dr., Cincinnati, OH 45227 513-703-6187 jon.schroeder@lathroptrotter.com Jon has been a mechanical equipment representative for 16 years with experience in air handling units, boilers, chillers, cooling towers, fans, turbines, and other ancillary products. During that time, he has selected equipment for many applications, in multiple industries, and assisted with the designs of the systems they support. From commercial to heavy industrial applications, Jon has broad experience in how mechanical systems utilize energy. While at Lathrop Trotter for the past 7 years, he has focused on boilers and ancillary equipment and how they are applied across market sectors. Jon has advanced knowledge of boiler and burner control systems that help improve operational efficiency. With a detailed minded focus on complex controls and mechanical system operation, he reaches for the more ambitious energy saving opportunities. He supports engineers, contractors, and end-users with writing and review of specifications, technology selection, and project execution. Jon is a graduate of the University of Cincinnati with a B.S. in Mechanical Engineering.
HH. Strategies & Technologies to Improve the Boiler Room Efficiency Jon Green, Mechanical Equipment Consultant Lathrop Trotter Co. Jon Schroeder, PE, Sales Engineer Lathrop Trotter Co.
Agenda 1. Things to consider when replacing a boiler. 2. Retrofit opportunities for existing boiler systems.
Metrics, Metrics, Metrics! If you can t measure it, you can t manage it! Consider installing: 1. Steam Flow Meters 2. Water Flow Meters 3. Gas Flow Meters 4. Temperature Probes 3 Boiler plant operators should be in the know...
Load Duration Curve 60000 Capacity Requirement (lbs/hr steam) 50000 40000 30000 20000 10000 0 0% 25% 50% 75% 100% Capacity Utilization (% of Time) Peak Load Load Following Base Load
60000 Load Profile Capacity Requirement 50000 40000 30000 20000 10000 0 Start of Day End of Day Dynamic Load Time Steady Load
Replacement Boiler: Opportunities for Efficiency Improvements
Boiler Sizing 1.Peak Load 2.Redundancy Requirement 3.Load Duration 4.Load Profile
Boiler Sizing Need for Redundancy Recommend 2 Boiler System Truly Redundant System 100% Load 100% Load
Boiler Sizing Need for Redundancy Recommend 2 Boiler System Efficient Load Following and Redundancy Recommend 3 Boiler System 50% Load 50% Load 50% Load
Boiler Sizing Seasonal Load Changes Process Load Changes Size one boiler for summer load. 75% Load 75% Load 25% Load
Boiler Sizing Heavy Base Load Process Load Changes Size one boiler for swing load, Pony Boiler 75% Fire Tube or Water Tube Base Load 75% Fire Tube or Water Tube Base Load 25% On Demand Steam Load
Boiler Types 2 1.Fire Tube Boiler 2.Water Tube Boiler 3.On-Demand Steam Boiler 4.Condensing Boiler
Fire Tube High & Low Pressure Steam Hot Water 81% Efficient Slow to respond to changes in demand Lower first cost Good for base loading 2
Water Tube 2 High & Low Pressure Steam Hot Water Higher Pressures High Temp Hot Water 85% Efficient Quick to respond to changes in load Good for load following Resilient to thermal shock
On- Demand Steam High & Low Pressure Steam 85% 87% efficient in turndown Cold to Steam in under 5 minutes 2 Real quick to respond to changes in load Peaking boiler Dynamic Loads Process Applications Hospital Applications
Condensing Boiler High & Low Pressure Steam Hot Water Highly Efficient 2 Low Return Water Temperatures Commercial Applications Small Footprint
Condensing Boilers defined Condensing boilers are water heaters fueled by gas or oil. They achieve high efficiency (typically greater than 90% on the higher heating value) by condensing water vapor in the exhaust gases and so recovering its latent heat of vaporization, which would otherwise have been wasted. https://en.wikipedia.org/wiki/condensing_boiler In order to condense the water vapor the return water temperature must be lower than 130 F
Condensing Boiler Efficiency Curve 98 96 94 92 Boiler Efficiency 90 88 86 84 82 80 78 80 90 100 110 120 130 140 150 160 180 Return Water Temperature Eff. Curve
Condensing Boiler Efficiency Curve
Return Water Temperatures 96% eff. Condensing Boiler 1 180 F Supply Water 96% eff. Condensing Boiler 2 Heating Coils Indirect HW Heaters Process Heat Exchangers This is most often not the case for existing Hot Water systems. 80 F Return Water To get the 96% efficient rating, you must have 80 F return water. This return water temperature is not easily changed in an existing HW loop.
Return Water Temperatures 85% eff. noncondensing Boiler 1 180 F Supply Water 85% eff. noncondensing Boiler 2 Heating Coils Indirect HW Heaters Process Heat Exchangers 140 F Return Water Flex tube HW boilers are resilient to thermal shock, highly efficient, and have the lowest life cycle cost with average life spans of over 30 years. Replacing old boilers with newer non condensing technologies gets you the best efficiency at a lower life cycle cost.
Radiated Heat Loss BTU s lost to the boiler room Must be re cooled if building has A/C
Keep BTU s in the boiler BTU s lost to the boiler room Must be recooled if building has A/C <.5% loss 2 3% loss
Radiated Heat Loss Most fire tube boilers have a 4% radiated heat loss. This loss is a FIXED % of the Maximum Continuous Rating. A fire tube boiler running at 75% will have 6% loss as a percentage of input. At 50% firing rate, the boiler will have 8% loss.
Other Things to Consider Look into revised Ohio Special Laws. No need to install overfired boilers. High Efficiency Burners Water Quality Management Reduce scale making boiler more efficient
Boiler Room Retrofit: Opportunities for Efficiency Improvements
Parallel Positioning Independently control combustion air, primary fuel, secondary fuel, and FGR (if used). Reduces fuel usage from 2% to 6% or more. site: Honeywell ControLinks
Parallel Positioning Valve Position Graph Fuel Position 90% 80% 70% 60% 50% 40% 30% 20% 10% Low Firing Rate High Start-up tech can program up to 24 points 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Air Position PP Curve Mechanical Linkage Curve Site: Honeywell Controllinks
Variable Frequency Drives VFD enables the motor to operate at the motor speed required for that moment of operation. As the Fan Laws indicate: RPM2 = RPM1 x [CFM2/CFM1] HP2 = HP1 x [CFM2 / CFM1]³ HP decreases by CUBE function of the speed!
O2 Trim The amount of excess O2 is approximately proportional to the efficiency loss. (e.g. 3% excess O2 3% efficiency drop) 90.00% Efficiency Impact by Excess O2 85.00% Site: Hays Cleveland Boiler Efficiency 80.00% 75.00% 70.00% 65.00% 2.0% 2.5% 3.0% 3.5% 4.0% 4.5% 5.0% 5.5% 6.0% 6.5% Excess O2 02 is about 20% of excess air
Lead-Lag Boiler Controls Most boiler designs lose efficiency when turned down. Lead-Lag enables the lead boiler to run at a higher firing rate to optimize efficiency. The controller will alternate lead boiler to even out operating hours.
Lead-Lag Boiler Controls 150 HP Boiler 1 Stage 1: 100% Stage 2: 0% 150 HP Boiler 2 Stage 1: 0% Stage 2: 100% Steam to Plant Lead Lag Controller
Thermochargers
Thermochargers Pre cooling inlet water to the economizer Log Mean Temperature Difference 256 F Flue Gas Economizer 7,482,211 BTU/hr 175 F Water 550 F Flue Gas 256 F Water Making the Economizer more Efficient Boiler 240 PSIG 40,000 lbs/hr
Condensing Economizer Additional BTU s in the stack, 303 F flue gas Capture latent heat from water vapor in the flue gas Stainless steel secondary economizer
Continuous Blowdown Heat Recovery
Combustion Air 1% efficiency loss per 20 F decrease in combustion air temperature Boiler manufacturer s rating assumes ISO at 68 F Find the waste heat! 1. Bring LP steam to be condensed. 2. Bring warmer air down from the top of the boiler room. 3. Bring waste heat from process.
Other Things to Consider Stack Thermometer Stack temperature should stay in a certain range. If out of range, something is wrong (scale, soot, combustion) Conductivity Sensor Blowdown based on conductivity of water as opposed to time or manual valve setting Stack Shut-Off Damper Draft can suck BTU s out of boiler when off-line. Spread Operating Setpoints Less pre-purge, less post-purge Less cycling.
Apply STG set to High Pressure Boiler Steam Pressure at Point of Use Potential Steam Pressure of Boiler Steam Turbine Generator Set
Apply STG set to High Pressure Boiler
Apply STG set to High Pressure Boiler
Preliminary Design Backpressure Steam Turbine Generator Design Mid Low Units Mass flow 54,369 39,000 25,000 lb/hr Inlet pressure 350 350 350 PSIG Inlet temperature 435.65 435.65 435.65 F Exhaust pressure 150 150 150 PSIG Performance Outlet speed 3,625 3,625 3,625 RPM Power at terminals 500 370** 130** kwe* *Power at generator terminal which includes generator efficiency ** Two Hand Valve Operation
Combined Heat & Power
Combined Heat & Power BYPASS EXHAUST SILENCER EXHAUST SILENCER AIR INLET FILTER GENERATOR DIVERTER VALVE HEAT RECOVERY STEAM GENERATOR (HRSG) GAS TURBINE SUPPLEMENTAL BURNER STEAM A DRIVING FORCE FOR POWER Caterpillar: Non-Confidential VPPG(0613)-45
Questions?? Jon Green jon.green@lathroptrotter.com 513 478 7288 Jon Schroeder, PE jon.schroeder@lathroptrotter.com 513 703 6187