Process Heating – Temperature Stability Under Dynamic Flow Rates

Direct Steam Injection for Sustainability

David Degelau

Hydro-Thermal CorpCertified Steam System Specialist

Presentation Summary

• Industrial heating methods• Direct steam injection (DSI) basics• Inherent properties for sustainability• Case Studies -

Industrial Heating MethodsDirect and Indirect

Steam Heating

Indirect or Direct Heating

Hot condensate out

Cold liquid in

Steam inCold Liquid In

Warm out

Steam inWarm out

Direct Fluid Heating - Sparging

• Sparging– Oldest method of direct

steam injection– Very inefficient– Prone to tank failure– Limited temperature

control– High maintenance costs

Common Sparging Problems

• Steam Hammer– Steam bubbles present in pipe– Bubbles combine and grow – Bubbles contact cool pipe wall and

collapse– Water rushes into void at high velocity

• Overheated zone around sparge nozzle

• Steam bubbles in pipe may damage tank

• Steam bubbles may escape into atmosphere

Direct Fluid Heating – Mixing Tees

• Mixing Tees– Very high maintenance– Prone to scaling and fouling– Steam hammer common– Potentially very dangerous– Limited temperature control

Direct Fluid Heating – Sparge Tube• Perforated tube sparger– Requires external steam control

valve– Very high maintenance– Prone to scaling and fouling– Steam hammer common– Limited temperature control due

to external control– Internal spring prone to

breakage

TM

Direct Steam Injectionvs.

Heat Exchangers

Contrast: Heat Exchanger vs. DSI• Indirect vs. Direct– Indirect = heat transfer only; no fluid mixing

Steam in(Hot)

Warm out

Cold Liquidin

Hot Condensate out

DSI Advantages• Rapid and uniform heating—important in starches

and food products• Can heat highly viscous fluids• Handles fluids that are difficult to heat—avoids

“bake-on”; abrasive slurries• Compact footprint• Minimizes plugging and fouling• Rapid response time

Energy Losses in the Heating Process

Water Treatment

Makeup water

Process Fluid

HX

Trap system

Boiler

Blow Down losses

Condensate losses

Stack losses

Flash losses

Heat loss

Steam

Pump power

Maintenance – Steam Systems

Water Treatment

SlurryHX

Trap system

Boiler

Condensate return

Blow Down

Makeup water

* Steam Survey, 2002 Greg Harrell, Ph.D., P.E. US Dept. of Energy

Internal ModulationSteam Velocity ~1500 ft/sec

Full Steam Pressure

(Psteam)High Velocity Steam Jet

Steam Nozzle

Combining tube

Stem / Plug Hot Liquid Discharge

Steam Inlet

Liquid InletPatented internal modulation DSI unit

Contrast: Sparging vs. DSIPaper mill – actual data• Reduced steam usage by 33%

– 932 lbs (422 Kg) with spargers– 624 lbs (283 Kg) with DSI

• Time Savings• Daily production increased by 32%

Maximum Boiler Energy Efficiency

• 100% efficient use of steam heat energy• Reduced steam consumption• Less energy required at boiler• 25% - 30% reduction is common• Lower energy costs

rev 3.09

Energy Comparison Report• Process fluid to be heated• Process flow rate• Incoming temperature• Desired temperature at output• Available steam pressure • % of condensate returned to the boiler• Boiler makeup water temperature• Hours per day in use• Boiler fuel cost per million Btu

Energy.gov

ENERGY Calculator

• Process fluid type• In/out temperature • Process flow rate• Hours per day in use • Steam pressure • % condensate returned• Boiler makeup water temperature• Boiler fuel cost per million BTU

Precise Temperature Control = Efficiency

175

180

185

190

195

200

205

0 50 100 150 200 250 300 350

Time (s)

Wat

er T

emp

erat

ure

, °F

PoorTemp

ControlTight

Temp Control

Tight temperature control results in

Lower set-point

Direct Steam Advantages

• Reduced steam consumption• Significantly lower energy costs• Low maintenance• Handles fluids that are difficult to heat—avoids “burn-on”;

highly viscous or abrasive slurries are no problem• Small size• Consistent, precise discharge temperature• No condensate return required

Sustainability & the Triple Bottom Line

• Economic– Sales, profits, ROI– Jobs created– Taxes paid

• Environmental– Air, water quality– Energy usage– Waste produced

• Social– Community impacts– Product responsibility

Sustainability Triangle

Firms that maximize the sweet spot thrive in changing environments

Direct Steam Injection Technology

Real-World Results Case Studies

Typical Food Processing Applications

Utility HeatingUtility Heating• CIP and COP water heatingCIP and COP water heating• Washdown hose stationsWashdown hose stations• Jacketed kettles Jacketed kettles • Sterilization potsSterilization pots• Can toppingCan topping• Bottle and can rinsingBottle and can rinsing• Thermal inactivationThermal inactivation

Process HeatingProcess Heating• Pet food processingPet food processing• Thick stock/paste heatingThick stock/paste heating• Baby food/formula Baby food/formula

cooking/pasteurizingcooking/pasteurizing• Sauce heating/thickeningSauce heating/thickening• Soup base cookingSoup base cooking• Condiments heatingCondiments heating• UHT pasteurizationUHT pasteurization• Starch cooking Starch cooking

Success #1 Processor Reduces Cycle Time (Slurry Heating)

• Meat slurry cooking• Customer needs to give

permission to use name,or use a ‘not to be named’ company format

Success #2 Plant Improves Throughput (Water Heating)

• Jacketed vessel tanks• Replaced inefficient tank sparger– Scaling clogged heater– Steam hammer damaged tanks

• DSI benefit impact– Self-cleaning design increased uptime by 20%– $2000/month saved by eliminating tank welding repairs– Consistent temperature set-point maintained• 60°F incoming water raised to 200°F• 400 gallons per minute (widely fluctuating)

Success #3Firm Improves Product – Slurry Viscosity • Product in extruder - viscosity kept at

acceptable levels to run smoothly and faster• Save time• Save energy

Summary: DSI = Sustained Benefits

• DSI effectively transforms heat energy– Near-instantaneous energy (heat) transfer– Effectively 100% efficient

• Significant measurable sustainable benefits – Energy savings– Sanitation effectiveness– Lower production costs– Reduced maintenance costs– Productivity improvement

• More work gets done = more bottom line profits!

Thank You!

David Degelau

400 Pilot CourtWaukesha, WI 53188

www.hydro-thermal.com

262.548.8900262.548.8908info@hydro-thermal.com

Hydro-Thermal CorpEngineer, Certified Steam System Specialist