Energy Efficiencyin Industrial Heating Systems גרדאן וולקאן Volkan GERDAN Mechanical Engineer Energy Manager (Buildings and Industry)
An Indian ProverbOnly when the last tree is cut.Only when the last river is polluted.Only when the last fish is caught. Only then will they realize that you cannot eat money.
Energy Efficiency• Energy Efficiency – Energy Saving • Two phrases that are most confusing. • Energy Saving is reduction of energy consumption with one or multiple measures, resulting in foreseen reduction or change in quality, quantity, comfort, safety etc. • Energy Efficiency is reduction of energy consumption while producing the same quantity in the same quality. (…or more in higher quantity)
First Step into Energy Efficiency 10 - 5 - 2 - 1 - 0.5 - 0.1 % What is more important? Leaking Tap Visible! Dropping Leaking Energy Invisible! Dropping
Energy in the Industry• Energy is used in two major forms in the industry: • Electricity • Heat• Many of the electricity consuming processes are heat sources by themselves.• A good portion of electricity consumption is caused by heat production or distribution. So there’s no possibility of a real reduction of energy intensity without taking both into consideration.
Energy in the Industry• Energy intensity • It’s basically the ratio of energy consumption with production. • Calculated as TOE of energy consumed per 1,000 USD sales revenues. • As example: Energy intensity of several countries e OECD 0.17 North America 0.20 Europe 0.14 Asia 0.17 EU27 0.12 Germany 0.11 UK 0.09 Japan 0.09 Switzerland 0.06 Israel 0.14
Energy in the Industry• Efficiency Increasing Projects (EIPs) 4R o Reduce o Reuse o Recycle o Rethink
Energy in the Industry• Efficiency Increasing Projects (EIPs) Optimization Projects: With no or limited investment costs easily applicable by the industrial facility itself. Example: Temperature setting in an office: 1°C means 10%
Energy in the Industry• Efficiency Increasing Projects (EIPs) Improvement Projects: With low investment costs implemented on the existing process. Example: Heat insulation of the existing pipes: Payback times less than half a year are possible.
Energy in the Industry• Efficiency Increasing Projects (EIPs) Upgrading Projects: With varying investment costs resulting in higher, sustainable energy efficiency changes. Example: Economizer integration to an existing steam boiler: 5% or more saving can be achieved without further costs.
Efficiency Increasing Projects• Heat Recovery • It’s one of the most applicable methods of energy efficiency increase. • Anything carrying excess heat is the source disregarding its temperature: • Discharged hot water from any process heater • Ovens (heat-recovery from multiple points possible) • Condensate return of the steam system • Boiler’s flue gases
Efficiency Increasing Projects• Economizers • Fuel savings 5% or more • Pre-heating of the boiler’s feedwater • Pre-heating of any other circuit is possible Steam Chimney at 10 bar Flue-gas Heavy Oil 184°C temperature ~160°C >200°C Economiser with Gas integrated by-pass ~120°C
Efficiency Increasing Projects• Economizers • Stand alone versions allow • Implementation to any steam boiler • Gas, light oil or heavy oil
Efficiency Increasing Projects• Ovens and Drying • Optimization project: Change of temperature setting (Rethink!) • Heat-recovery options: • Air recirculation 15 – 40% efficiency increase • Air pre-heating 15 – 25% efficiency increase
Efficiency Increasing Projects• Case Study: Paper Mill Air Economizer Exhaust Paper Mill: 2.0 t/day of 300 g/m2 paper increased to 3.1 t/dayFresh-Air from from from Flash Steam CHP Plant steam Boiler810 kW out of 3,370 kW recovered !!! Implementation of heat recovery system to an existing paper mill: 24% increase of energy efficiency 50% increase of production without increase of energy consumption Investment amount: Annual Savings: Payback Period 220,000 EUR 7,806,000 kWh – 200,000 EUR Less than 1.5 years
Efficiency Increasing Projects• Using the “high” calorific value of the fuel via condensation technology Condensing Boiler High Low Calorific Value Used Heat Heating Calorific System Value Condensation Vapor
Efficiency Increasing Projects What is Condensation Technology?
Efficiency Increasing Projects• Summary of Heating Air (O2) Losses Fuel Heating Natural gas, Fuel-oil, Diesel-oil etc. Energy (C,H,O …) + CO2 + H20
Efficiency Increasing Projects• Heat Losses and Recoveries Chimney Heat Losses Very Low Flue Gas Temperatures Losses of Energy Due To The Latent Heat In Water Vapor Condensation
Efficiency Increasing Projects• Is 110% efficiency possible? miles/h km/h 100 miles/h > 100 km/h
Efficiency Increasing Projects• Is 110% efficiency possible? Lower Heating Value Hs Higher Heating Value Hi The latent heat in water vapor is not The latent heat in water vapor is taken into consideration and the rest taken into account and the total is is accepted to be 100%. accepted to be 100%. For natural gas: 8.250 kcal/m3 9.155 kcal/m3 100 units of energy 111 units of energy
Efficiency Increasing Projects• Losses of a boiler • Chimney losses • Cooling losses• Chimney losses occur only when the burner is running.• Cooling losses occur • Stand-by losses: During stand-by on a fixed temperature (when the burner is off) • Radiation losses: During the operation (when the burner is running)
Efficiency Increasing Projects• Radiation losses are relative to • Dimensions • Water volume • Weight Stand-by and radiation losses Chimney losses Fuel losses
Efficiency Increasing Projects• The cooling losses are the sum of radiation and stand-by losses. Burner running : Radiation losses 1,2% Burner off : Stand-by losses 0,8% Total cooling losses are 2% in average.• During the operation of the burner, combustion and chimney losses are happening. Chimney losses : 7% Combustion losses : 7%
Efficiency Increasing Projects• Stand-by losses are depending on stand-by duration • No stand-by means • No stand-by losses.• They are less than chimney losses. Stand-by losses are in positive relation with boiler outshell area per kW power Higher boiler power has relatively less area.• The ratio between chimney and stand-by losses: in 70 kW 1:3 in 1000 kW 1:5
Efficiency Increasing Projects• Combustion can affect both chimney and stand-by losses.• In best way, the combustion is realized without any interruptions while changing the capacity: Modulation On – Off Operation Operation with modulation
Efficiency Increasing Projects• Capacity modulation • Boilers and burners are selected for the peak load. • Normally they are running on lower capacities. • In case of an on/off controlled burner, partial loads cause very high cycling frequency!
Efficiency Increasing Projects• Every cycling (on/off) causes Reduction of burner economic life A swap away period of the fan Air sent to the chimney together with the rest heat A period of bad combustion conditions (with very low efficiency) Loss of unused fuel Stand-by (cooling) losses• Annual losses via cycling On-off burners: ~ 5% Modulating burners: ~ 1%
Efficiency Increasing Projects• How to control the combustion? Chimney draught (Pa) = h x (r1-r2) h = Height of the chimney (m) r1= Density of outdoor air (kg/m3) r2= Density of flue-gas (kg/m3) Boilers with jet burners Burner’s blower and chimney run as two fans in serial connection. Combustion air is under effect of ambient conditions.
Efficiency Increasing Projects• How to control the combustion? Start-Up / Colder Day Warmer Day Maintenance Day To = 5°C To = 30°C To= 20oC Higher draught and Lower draught and Higher air surplus Lower air surplus Low Efficiency Low Efficiency and Soot
Efficiency Increasing Projects• Choosing the right burner is an energy increasing project! • One staged burners • Two staged burners • Modulating burners • Modulating burners with pneumatic mixing (soot-free burners)• Larger capacities: • Frequency controlled (> 2,000 kW) • Oxygen controlled (> 3,000 kW)
Efficiency Increasing Projects• Combined Heat and Power Generation • Cannot be understood in the scope of energy efficiency. • On the other hand it’s an important method of cost reduction. • CHP basically allows to switch from one energy source to another. • Important primary energy savings and reduction of CO2 emissions are generated
Efficiency Increasing Projects• Combined Heat and Power Generation • Is a CHP system applicable in my industrial facility? • If a facility needs • Heat • Electricity then the answer is “YES”. For CHP, heat is always the prior demand.
Efficiency Increasing Projects• Combined Heat and Power Generation Thermal Losses 68% Fuel Electricity 100% 32% Thermal & Mechanical Losses 20% Electricity Steam Fuel Useful Hot water 100% 80% Hot air CHP Plant Chilled water
Efficiency Increasing Projects• Case Study: Plaster Factory • Implementation of CHP’s heat recovery system to the existing tunnel ovens as hot-air • Feed-in of excess electricityInvestment amount: Annual Savings: Annual Income via Feed-In: Payback Period910,000 EUR 180,000 EUR 240,000 EUR 2.2 yearsAnnual Primary Energy Savings: 1,480,000 kWhAnnual Reduction of CO2 Emissions: > 11,600 t eq
Other Topics of Energy Efficiency• Compressed air systems: Up to 80% efficiency increase opportunities• Implementation of renewable energy resources• Thermal insulation• Temperature settings• Thermal storage• Green buildings (factories)• Recycling and waste management• Energy monitoring (You cannot reduce if you cannot monitor!)