Mechanical Engineering College of Engineering, Design and Physical Sciences Institute of Energy Futures Energy Efficient and Sustainable Technologies Theme ENERGY EFFICIENCY IN PROCESS INDUSTRIES Dr Hussam Jouhara BSc (first), PhD, CEng, IntPE, FIMechE, FIEI, MInstR, SFHEA
OVERVIEW Waste Heat Recovery HVAC Renewable Energy Advances
Conventional Waste Heat Recovery Scenarios
21 May 2018 Source: US DOE Presentation Title 4
Conventional Waste Heat Recovery Systems
Recuperators 21 May 2018 Recuperators recover exhaust gas waste heat in medium to high temperature applications Source: US DOE Presentation Title 6
Regenerator 21 May 2018 Source: US DOE Presentation Title 7
Regenerator 21 May 2018 Source: US DOE Presentation Title 8
Economizers 21 May 2018 Finned tube heat exchangers are used to recover heat from low to medium temperature exhaust gases for heating liquids Presentation Title 9
Waste Heat Boilers 21 May 2018 Source: US DOE Presentation Title 10
Direct contact heat recovery systems 21 May 2018 Presentation Title 11
Waste Heat Recovery in Challenging Scenarios
21 May 2018 Why? Presentation Title 13
Challenging waste heat recovery scenarios Many industrial processes generate highly difficult exhaust conditions that can be characterised as follows: 1. High temperatures / mass flows 2. High particulate content that is abrasive and / or can cause fouling 3. Highly corrosive, acidic content SO2, SO3, NO2, etc.
The Solution Heat Pipe
Conventional heat exchangers Heat Pipe heat exchangers Shell & tube heat exchanger Heat pipe heat exchanger running since 2008 Same operational conditions 16
Heat Pipes What are they?
Low temperature heat pipe Working fluid High temperature heat pipe
Multiple Redundancy Each pipe operates independently so unit is not vulnerable to a single pipe failure This prevents cross contamination each heat pipe acts as an additional buffer between the two fluids Intermediate Pipe Working Temperature Allows higher exhaust temperature limits on some applications Better fouling managment Use of smooth pipes allows exchangers to be used in high particulate or oily applications Ease of Cleaning & Maintenance Can be maintained in situ (no uninstall) Manual/automated cleaning systems Highly Scalable, Customisable & Configurable Modular design allows on site assembly Can be designed for future expansion, to meet specific application or operational needs Isothermal Operation no hot or cold spots Eliminates cold corners and condensation Allows greater energy recovery Better longevity for thermal oil Reactivity Fast reaction time, offers different control options and suitable for sensitive apparatus: does not require preheating Robust Materials and Long Life Design allows pipes to freely expand and contract, thus no thermal stress on structure Thick pipe walls resist erosion/corrosion Passive devices No need for pumping energy to drive the heat transfer process through the heat pipe
Typical geometries of heat pipe based waste heat recovery systems
A schematic of a typical heat pipe unit
Cross flow HP units: Gas to air
Cross flow HP units: Gas to air Hot exhaust Preheated combustion air Cooled exhaust to the new stack Cold combustion air Heat pipe heat exchanger
Cross flow HP units: Gas to air 10m HOT STOVES WASTE GAS HEAT RECOVERY
STEAM GENERATION FROM WASTE HEAT 21 May 2018 Duty: Circa 6MW Steam generation rate: 8t/h ROI: < 7 months 26
Steam Condenser, Food, Dirty Steam, Ireland
Throughflow HP units Through-Flow = for exhaust temperatures above 500C
SAMPLES OF RECENT PROJECTS G2W, Shale Gas Well Head Fracking, Thermal Oxidiser, Canada 2013
21 May 2018 Maintenance Panels Manual cleaning with compressed air or high pressure water Pipes rows are easily accessible by lance Aerodynamic trap Regular dust removal Automated actuator Moving plate system Active vibration device Sonic Horn - Inside unit Cleaning / Anti-clogging Solutions Presentation Title 30
Cross flow HP units: A combination of various units
Thermal Storage And Heat Recovery System From Process Waste Steam 21 May 2018 Discharging Charging
Heat Pipe Based Waste Heat Recovery Systems: Case Studies
Exhaust to Coke Gas Unit, Steel mill Blast Furnace, Czech Republic 2011 Gas to Air Exhaust Temp In/Out 286 C/156 C Coke Gas Temp In/Out 62.2 C/197 C Exhaust/Air Mass Flow 97,551/97,551 Kg/h Energy Recovered 12,626 KW Recovered Energy 800K p/a Project Cost 400,000 * Payback Period Circa 6 Months * /KW recovered 31.67 * * Estimated figures based on extrapolated installed costs Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Heat pipe GPH 12.6 MW duty Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation Each unit consists of 1575 X 7.6 Mtr helically finned, distilled water stainless steel heat pipes Unit performance increased significantly after upgrade Repeat order secured Sep 2013 delivery Full turnkey replacement delivered through Czech local distributor 34
Steam Generator, China National Offshore Oil Corp, China Sea, April 2016 Gas to Steam Exhaust Temp In/Out Water/Steam Temp In/Out Exhaust Flow/Steam Rate Energy Recovered Recovered Energy Project Cost Payback Period 400 C/250 C 50 C/190 C 130,000/ 8,000 Kg/h 6,400 KW 2,100K p/a 1,200K 7 Months /KW recovered 328 Econotherm GA 6400 smooth pipe 2 stage steam generator On-site assembly High reliability required for offshore service Low footprint required by space limitations Low pressure drop, less parasitic load Multi Robust Material Efficient Cleaning & Low Pressure Redundancy Maintenance Drop Instant start up from gas turbine, no pre-heating required Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation 35
G2W, In Line Through-Flow Recuperator, Biomass Incinerator, Bologna, Italy Gas to Water Exhaust Temp In/Out 610 C / 150 C Water Temp In/Out 73 C / 90C Exhaust/Water Mass Flow 17,500 Kg/h Weight of unit 5,000 Kg Exhaust pressure drop 400 Pa Energy Recovered 2,100 KW Recovered Energy Value 315K p/a Heat Exchanger Cost 172,500 Payback Period <18 Months Price pe r KW recovered 140/kW Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation GW throughflow heat exchanger 2.1MW waste water treatment plant biomass incinerator plant: highly robust low fouling unit High organic particulate matter in exhaust; removable panels incorporated for cleaning Low fouling, easy cleaning and maintenance, high reliability 36
Steam Condenser, Food, Dirty Steam, Ireland, 2010 Steam Condenser / Hot Water Steam Temp In/Out 105 C/ 95 C Water Temp In/Out 10 C/ 88 C Exhaust/Water Mass Flow 844 / 8,000 Kg/h Weight of unit 300 Kg Exhaust pressure drop N/A Energy Recovered 446 KW Recovered Energy Value 2 x 20K p/a Heat Exchanger Cost 2 x 10K Payback Period 6 Months Price per KW recovered 22 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation SC model 400 smooth/finned hybrid pipe through-flow heat exchanger 440 kw process water heater Contaminated steam; regulatory requirement to condense, fuel savings, stainless steel Eliminated existing air-cooled equipment 37
3 Kiln Heat Recovery, RAK Ceramics, UAE, April 2016 Gas to Air Exhaust Temp In/Out 235 C/162 C Air Temp In/Out 34 C/160 C Exhaust/Air Mass Flow 41,771/ 27,400 Kg/h Energy Recovered 970 KW Recovered Energy 209K p/a Project Cost 190K Payback Period 11 Months /KW recovered 195 GA 970 smooth pipe heat exchanger 970 kw drier air pre-heater sourcing exhaust from 3 tunnel kilns Pre-heated air delivered to multiple usage points High particulate matter exhaust from kilns Integrated moving plate cleaning system
TDO Heat Pipe Recovery, COSMO Films Limited, February 2016 Exhaust to Air Exhaust Temp In/Out Air Temp In/Out Exhaust/Air Mass Flow Energy Recovered 140 C/80 C 35 C/105 C 13,200 Kg/h 219 kwth Recovered Energy Project Cost Payback Period /KW recovered GA 970 smooth pipe heat exchanger Reduced energy consumption by returning existing heat energy - Up to 220 kw per hour Improvement of film quality by - Preheated fresh air - Reduced temperature differences - Reduced pressure differences Higher air conformity in the TDO oven Less maintenance in the TDO - By controlled absorption of condensate - By simple collection and removal Less emission to the environment Less condensate at slots, holes and cold bridges by - Reduced flow of cold air - Controlled overpressure in the oven
Air Pre-Heater, Dow Chemicals, Freeport, Texas Gas to Air Exhaust Temp In/Out 360 C/142 C Air/ Temp In/Out 26 C/254 C Exhaust/Air Flow Rate 46,856/ 49,124 Kg/h Energy Recovered 3,100 KW Recovered Energy 563K p/a Project Cost 750K Payback Period 19 Months /KW recovered 241 GA 3100 finned pipe counter flow air pre-heater Ethylene cracking furnace combustion air pre-heater Distilled water working fluid pipes ASME design code compliant, fully NDT tested Carbon steel finned pipe design
Multi-stage, in series, steam/water, natural gas, Spirax Sarco Italy 2012 Multi-stage Steam Generator and Water Pre-Heater Exhaust Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 420 C/ 160 C 160 C/ 198 C (12 bar) 11,484/ 900 Kg/h 1852 Kg 700 Pa 520 KW 19K p/a Heat Exchanger Cost 19K Payback Period 60 Months Price per KW recovered 36 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Anaerobic digester genset in food industry Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation 1 stage of 198C/12 Bar steam generation, left hand side 2 stages of water heating delivered by 2 standard modules, visible on right of unit Pipes screwed in from underneath on standard modules; modules can be removed individually Hinged access doors for easy cleaning, sealing nuts will be replaced by latches on future units 41
Gas to Air Unit, Automotive, Aluminium Furnace, USA 2008 Gas to Air Exhaust Temp In/Out Air Temp In/Out Exhaust/Air Mass Flow Energy Recovered Recovered Energy 400 C/266 C 30 C/293 C 12,000/ 6,374 Kg/h 528 KW $155K p/a Project Cost $150K Payback Period 16 Months $/KW recovered $123 ( 76) Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Econotherm GA 360 smooth pipe heat exchanger Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation 500 kw combustion air pre-heater High particulate matter exhaust from furnace Low fouling, easy cleaning and maintenance, high reliability Unit positioned outside main factory premises Customer advised it was not possible by consultants (acid etc) 42
Gas to Air Unit, Antique Ceramics, Horizontal Roller Kiln, India 2010 Gas to Air Exhaust Temp In/Out Air Temp In/Out Exhaust/Air Mass Flow Weight Pressure drop Energy Recovered Recovered Energy Project Cost 316 C/ 122 C 35 C/ 215 C 9,800 Kg/h/ 12,000 Kg/h 8000 kg 392 Pa 606 KW RS 4.5m p/a RS 6m Econotherm GA 360 smooth pipe heat exchanger Prior attempts to deploy conventional equipment resulted in unit failures and lost investment 600 kw combustion air pre-heater Highly acidic (SO2), sticky particulate matter exhaust from kiln dryer exhaust Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Innovative automatic pipe cleaning mechanism: moving plate system Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation 43
Conoco Phillips Gas Compressor Station, Canada 2012 Gas to Water Exhaust Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 454 C/ 180 C 50 C/ 90 C 28,567/14,470 Kg/h 14,470 Kg/h 5,100 Kg 750 Pa 1,200 KW 180K p/a Heat Exchanger Cost 45K Econotherm GW 1200 finned to finned pipe heat exchanger 1.2MW process water heater (Genset) Remote location: chosen for high reliability, no single point of failure, low fouling, easy cleaning and low maintenance, small footprint and weight Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Client indicates they will order many more once first is proven Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation 44
G2W, Shale Gas Well Head Fracking, Thermal Oxidiser, Canada 2012 Gas to Water Exhaust Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 816 C/ 150 C 5 C/ 16 C 11,016/180,000 Kg/h 3,600 Kg 800 Pa 2,260 KW 360K p/a Heat Exchanger Cost 65K Payback Period <3 Months Price per KW recovered 27 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation GW 2000 hybrid pipe heat exchanger 2.2MW fracking water heater: highly robust mobile unit for travelling around Canada High particulate matter exhaust from furnace; removable panels incorporated for cleaning Low fouling, easy cleaning and maintenance, high reliability 45
Biofuel plant gensets,, UK 2012 Gas to Water two pressure vessels Exhaust Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value Heat Exchanger Cost Payback Period 440 C/ 371 C 75 C/ 98 C 46,500/ 36, 210 Kg/h 1,556 Kg 850 Pa 750 KW 175K p/a 16,675K 1 Month Price per KW recovered 17 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Scalable & Reactivity Isothermal Econotherm GW 650 double water vessel heat exchanger Temperatures Customisable Operation 750 kw unit, low pressure drop The reason for the shape was the large duct diameter, necessitating a large cross sectional area on our unit. However they only needed to recover a small amount of energy to get the maximum grant - hence a small temperature drop. This meant a lot of heat pipes across the unit, but only a small number of rows. The shape necessitated two water 46
Gas to Water unit, Building Materials, Steam, Italy 2012 Gas to Water (pressurised) Exhaust Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 490 C/ 119 C 112 C/ 116 C (5 bar) 7,300/ 220,000 Kg/h 1,500 Kg 800 Pa 1023 KW 180K p/a Heat Exchanger Cost 20K Payback Period <3 Months Price per KW recovered 18 ( 15) Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation Higher than expected / better performance than heat exchanger previously installed: Primary Smoke Ti = 525 C T = 154 C Q = 7314 kg / h; Secondary hot water Ti = 115 C T = 117.5 CQ = 300,000 kg / h., Energy Potential = 871 kw We have found in the field to the new heat exchanger the following data: Primary Smoke Ti = 490 C T = 119 C range not measured; Secondary hot water Ti = 112 C T = 116 CQ = 220,000 kg / h; Energy Potential = 1023 kw From the above it can be seen that we have improved the performance of the system, increasing the recovered heat by 15% and for this we about the construction company Spirax-Sarco. Replaced much larger shell and tube system 47
Biomass Incinerator, exhaust G2O or G2W, Air Burners, USA Water or thermal oil for ORC energy generation Exhaust Temp In/Out Water /Glycol Temp In/ Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 950 C/ 600 C 203 C/ 254 C (12 bar) 28,800/ 57,000 Kg/h 4320 Kg 450 Pa 760 KW 140K p/a Heat Exchanger Cost 25K Payback Period <3 Months Price per KW recovered 32 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Mobile thermal oxidiser for use in forestry and other mobile applications Low Fouling Working Temperatures Scalable & Customisable Reactivity Isothermal Operation Process - or for ORC energy generation - hot water or thermal oil Range of capacities High temperature 48
Gas to Oil unit, Waste Processing Plant, Pyrolysis Gas to Oil (for ORC) Exhaust Temp In/Out Oil Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 1000 C/ 250 C 135 C/ 280 C 4,150/ 9,200 Kg/h 1,800 Kg 650 Pa 940 KW 150K p/a Heat Exchanger Cost 25K Payback Period 3 Months Price per KW recovered 23 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation GW940, smooth/finned hybrid pipe through-flow heat exchanger 940 kw thermal oil heater; very high inlet exhaust temperature catered for by through-flow model To feed and ORC engine to generate electricity Very high particulate matter exhaust from furnace; removable panels incorporated for cleaning Low fouling, easy cleaning and maintenance, high reliability 49
Steam Condenser, Food, Dirty Steam, Ireland, 2010 Steam Condenser / Hot Water Steam Temp In/Out Water Temp In/Out Exhaust/Water Mass Flow Weight of unit Exhaust pressure drop Energy Recovered Recovered Energy Value 105 C/ 95 C 10 C/ 88 C 844 / 8,000 Kg/h 300 Kg N/A 446 KW 2 x 20K p/a Heat Exchanger Cost 2 x 10K Payback Period 6 Months Price per KW recovered 22 Multi Redundancy Robust Material Efficient Cleaning & Maintenance Low Pressure Drop Low Fouling Working Scalable & Reactivity Isothermal Temperatures Customisable Operation SC model 400 smooth/finned hybrid pipe through-flow heat exchanger 440 kw process water heater Contaminated steam; regulatory requirement to condense, fuel savings, stainless steel Eliminated existing air-cooled equipment 50
Installed Units
21 May 2018 Heat Pipe based HVAC Systems Presentation Title 52
Heat Pipe based Radiator (Jouhara & Robinson, 2010)
Energy efficient Air Conditioning Systems. Conventional dehumidification method
Heat pipe based dehumidification method
Waste Heat Recovery, Loop HP HEX
Humidity ratio - g/kg(a) Humidity ratio - g/kg(a) Pressure: 101325 Pa Waste Heat Recovery, Loop HP HEX Pressure: 101325 Pa 110 120 110 120 30 40 Enthalpy - kj/kg(a) 50 60 70 80 20 2 3 90 100 Saturation temperature - deg C 30 1 Coil Energy Load 52kW Coil Energy Load 52 kw 0.90 Volume - cu.m/kg(a) 0.95 20 10 120 110 100 90 80 The assumed humid air mass flow rate is 1 kg/s 30 40 Enthalpy - kj/kg(a) 50 60 3 100 90 80 70 20 Saturation temperature - deg C 4 30 2 1 Coil Energy Load 47kW Coil Energy Load 47 kw 0.90 Volume - cu.m/kg(a) 0.95 20 10 120 110 100 90 80 20 10 80% 20 10 80% 0.85 10 0 0.80 60% 40% 20% 0.85 Heater Energy Consumption 7.2kW (Electric) Heater Energy Consumption 7.2 kw (Electric) 70 60 10 0 0.80 60% Heating Energy Consumption 0kW 40% 20% 70 60 0 10 20 30 40 50 Dry bulb temperature - deg C 0 10 20 30 40 50 Dry bulb temperature - deg C The chilled coil becomes 10% smaller and no heaters are needed. (Jouhara, 2009)
Building Waste Heat Recovery SHP HEX Inclination Mechanism
21 May 2018 The Heat Mat Solar Roof 59
Funded by DECC The Flat Heat Pipe
13/01/16 Presentation Title 63
Patents 1. Jouhara, H., Lester, S., (2014), "Heat Transfer Apparatus", UK patent application No. 1410924.3. Status: Filed. Filing date: 19/06/2014. Applicant: Flint Engineering & Econotherm (UK) ltd. 2. Jouhara, H., Lester, S., (2014), "Radiator", UK patent application No. 1410933.4. Status: Filed. Filing date: 19/06/2014. Applicant: Flint Engineering.
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