Thermal Process Engineering For Brewers
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Thermal Process Engineeringfor Brewers10/24/2014Basics in Theory and PracticeFred M ScheerBrewing & Process TechnologyKrones IncPhone: 414 688 7472Email: Fred.Scheer@kronesusa.com

2 kronesThermal ProcessEngineering for BrewersBeispieltextTable of Content Why is a Basic Knowledge important for Brewers? Necessary Basics of Thermodynamics Heat and EnergyDefinition of Thermodynamic ParametersThermal Energy and PowerHeat TransferHow can Brewers improve the k-value and theHeat Transfer? Practical Calculations in the Brewery10/24/2014 MashingWort BoilingWort Cooling with a Plate Heat ExchangerImportance of Tank InsulationFermentation Final Remarks

3 kronesThermal ProcessEngineering for BrewersBeispieltextWhy is a Basic Knowledge important for Brewers? Heat exchange can be found everywhere in the brewery!Heating up the mash and hold thetemperature break10/24/2014Wort boiling

4 kronesThermal ProcessEngineering for BrewersBeispieltextWhy is a Basic Knowledge important for Brewers? Heat exchange can be found everywhere in the brewery!10/24/2014Wort coolingHeat transfer between a tank and itsenvironment (for instance brewing liquor)

5 kronesThermal ProcessEngineering for BrewersBeispieltextWhy is a Basic Knowledge important for Brewers? Heat exchange can be found everywhere in the brewery!Fermentation and beer storage10/24/2014Flash pasteurization

6 kronesThermal ProcessEngineering for BrewersBeispieltextWhy is a Basic Knowledge important for Brewers? Average heat/cooling consumption of a 83,000 bbl brewery (100,000 hl)Heat consumption of thebrewhouse:Of that mashing (infusion):3 kWh/bbl sales beerOf that boiling (10% totalevaporation):13.5 kWh/bbl sales beerHeat consumption of the wholebrewery:44.1 kWh/bbl sales beerCooling consumption of the wholebrewery:10/24/201422.5 kWh/bbl sales beer7.7 kWh/bbl sales beer 50% of the totalheat are consumedin the brewhouse!

7 kronesThermal ProcessEngineering for BrewersBeispieltextWhy is a Basic Knowledge important for Brewers? Heating oil price development in the past10/24/2014 The price for heating oil rose in the past and will be unstable in the future!

8 kronesThermal ProcessEngineering for BrewersBeispieltext10/24/2014Why is a Basic Knowledge important for Brewers? Heat transfer is part of many processesduring beer production. The knowledge about the physics behind isimportant to ensure high product quality. It also offers the opportunity to improve yourwort-/beer taste. Understandingheattransfermeansrecognizing potential to save money in thefuture. Saving primary energy means to be moreindependent of the uncertain developmentof heating oil prices. Additionally,decreased.CO2-Emissionmaybe

9 kronesThermal ProcessEngineering for BrewersBeispieltextTable of Content Why is a Basic Knowledge important for Brewers? Necessary Basics of Thermodynamics Heat and EnergyDefinition of Thermodynamic ParametersThermal Energy and PowerHeat TransferHow can Brewers improve the k-value and theHeat Transfer? Practical Calculations in the Brewery10/24/2014 MashingWort BoilingWort Cooling with a Plate Heat ExchangerImportance of Tank InsulationFermentation Final Remarks

10 ThermalBeispieltextProcess Engineering for BrewerskronesHeat and Energy What is heat?Heat (abbreviation 𝑸 ) is energy that is being transferred based on a temperature differenceof a system and its environment (or between two systems) across the common systemboarder.Heat comes from the higher temperature level to the lowertemperature level. The results are often serious.10/24/2014 Therefore, heat always flows from the system with a higher temperature level to thesystem with lower temperature level (according to the second law of thermodynamics). Heat flow (𝑸̇ )is determined as the transferred heat in a certain time interval. It can beconsidered the same as the thermal power.

11 ThermalBeispieltextProcess Engineering for BrewerskronesHeat and Energy Heat is transferred energy. But how is energy defined? Example: What contains more energy: a cup of hot soup or a glass of water? Obviously, the soup has got more energy because of its higher temperature.10/24/2014 Energy is the ability of a system to work or to release heat.

12 ThermalBeispieltextProcess Engineering for BrewerskronesDefinition of Thermodynamic Parameters Specific heat capacity 𝑐𝑝 (also called specific heat): The specific capacity describes which quantity of heat is required to rise the temperatureπ‘˜π‘˜of 1 kg of a certain substance by 1 Kelvin. The physical unit is. The 𝑐𝑝 value onlyπ‘˜π‘˜ 𝐾applies for a certain pressure.FluidWaterπ‘˜π‘˜] for atmospheric pressureπ‘˜π‘˜ 𝐾3.73Mash (20 P)3.60Mash (25 P)3.46AirSpecific heat value4.18Mash (15 P)Wort10/24/2014𝑐𝑝 [4.0 – 4.11.005 With increasing density of the mashes, the specific heat decreases.

13 ThermalBeispieltextProcess Engineering for BrewerskronesDefinition of Thermodynamic Parameters Specific Enthalpy β„Ž: Enthalpy means the content of heat of a body. The specific enthalpy is the heat inπ‘˜π‘˜π‘˜π‘˜relation to mass [ ]. For fluids applies:β„Ž 𝑐𝑝 Δ𝑇𝑇: Temperatureenthalpy specific heat value X delta Temperature Enthalpy of vaporization/-condensation π‘Ÿ [π‘˜π‘˜π‘˜π‘˜] is the content of heat that isrequired/released for changing the state of aggregation from liquid to vapor state andvice versa. The amount of enthalpy depends on the pressure level of the system (vaporpressure!). For condensing saturated steam applies:Pressure of the system(abs.)10/24/20141.0β„Ž π‘Ÿπ‘˜π‘˜π‘Ÿ [π‘˜π‘˜] for water/vapor 4

14 ThermalBeispieltextProcess Engineering for BrewerskronesThermal Energy and Power How can you calculate the energy of a fluid?Generally:For fluids:Saturated steam:Specific Enthalpy β„Žπ‘„ π‘š β„Žπ‘„ π‘š 𝑐𝑝 Δ𝑇𝑄 π‘š π‘Ÿπ‘š: Mass ofthe materialSpecific heatcapacity 𝑐𝑝Enthalpy of vaporization/-condensation π‘Ÿ The required thermal power can be found by considering the time to heat up a body/fluid:𝑄̇ 𝑄𝑑10/24/2014Further examples concerning brewing in a later chapter𝑑: Time

15 ThermalBeispieltextProcess Engineering for BrewerskronesHeat Transfer 3 possibilities of transferring heat through avessel wall: Heat conduction Convection Heat radiation (not considered in thispresentation, but in fact has influence onwort boiling and cooling outdoorfermentation tanks)10/24/2014 In reality, there is always a combination ofthe three types.

10/24/201416 ThermalBeispieltextProcess Engineering for Brewerskrones

17 ThermalBeispieltextProcess Engineering for BrewerskronesHeat Transfer Heat conduction and thermal conductivity Ξ»(β€žlambdaβ€œ ): Material property that describes how bigthe temperature difference between thein- and outside of a wall is.𝐴𝑄̇ Ξ» (π‘‡π‘Šπ‘Š π‘‡π‘Šπ‘Š )𝑠Material10/24/2014Stainless SteelΞ»[𝑾] for 68 Fπ’Ž Temperature levelwall 1 π‘‡π‘Šπ‘ŠThermalp[ower SteamHeat transferarea 𝐴Temperature levelwall 2 π‘‡π‘Šπ‘ŠWallthickness 𝑠

18 ThermalBeispieltextProcess Engineering for BrewerskronesHeat Transfer Convection 10/24/2014 SteamWallThe convection coefficient 𝜢 describes theability of a fluid (gas) to gather / releaseenergy from / to the surface of a wall.𝑄̇ Ξ±1 𝐴 (𝑇1 π‘‡π‘Š1 )π‘ŠΞ± (unit) can be specified byπ‘š2 𝐾experiments using dimensionless numbers(e.g. Reynold’s number).Ξ±-value depends on: Material properties (of the wall and ofthe fluid) Fluid flow near the wall (higherturbulents result in better Ξ±)Steam temperature 𝑇1Temperature levelwall 1 π‘‡π‘Šπ‘ŠHeat transferarea 𝐴α1Wallthickness 𝑠

19 ThermalBeispieltextProcess Engineering for BrewerskronesHeat Transfer The real heat transfer:Steam In real heating (and cooling!) processes, acombination of conductivity andconvection takes place. The whole heat transfer is characterizedby the k-value. π‘˜ 1Ξ±1 1𝑠λ1 Ξ±2𝑄̇ π‘˜ 𝐴 (𝑇1 𝑇2 )Temperature gradient:The driving force of heatHeat transfertransferConventional mash tuns obtain a k-valueπ‘Šof 1,000 – 1,500 2π‘š 𝐾10/24/2014Steamtemp. 𝑇1 The k-value is a dimension that estimateswhether much or less heat is transferredarea οΏ½2Wallthickness 𝑠Mash temp. 𝑇2

20 ThermalBeispieltextProcess Engineering for BrewerskronesHow can Brewers improve the k-value and the Heat Transfer? Basically, the higher the turbulences in theproduct and the heating medium, the better thek-value Possibilities for higher turbulences: Proper agitation during mashing, including afitting agitator shape (propeller mixer) Special surface of the mash tun/kettle Pillow Plates, increasing the heatπ‘Šexchange area (k-value: 2,000 2 )10/24/2014 π‘š 𝐾Using a circulation pump during boiling. Avoid fouling and calcification! Correct andproper cleaning of the tanks is important! Shape of the heating/cooling pipes. Improved shape of the heat exchanger platesof the wort cooler or flash pasteurizer.Flow profileof an evensurfaceFlow profileof astructuredsurface

21 ThermalBeispieltextProcess Engineering for BrewerskronesTable of Content Why is a Basic Knowledge important for Brewers? Necessary Basics of Thermodynamics Heat and EnergyDefinition of Thermodynamic ParametersThermal Energy and PowerHeat TransferHow can Brewers improve the k-value and theHeat Transfer? Practical Calculations in the Brewery10/24/2014 MashingWort BoilingWort Cooling with a Plate Heat ExchangerImportance of Tank InsulationFermentation Final Remarks

22 ThermalBeispieltextProcess Engineering for BrewerskronesMashing Assumptions 10/24/2014 Mash volume 𝑉:58 hl or 5,800 lHeat capacity of the mash 𝑐𝑝 :3.6Transfer mash temperature π‘‡π‘œπ‘œπ‘œ :351 K (172 F)Heating rate 𝐻𝐻:1 K/minDensity of the mash ρ𝑀 :Mash-in temperature 𝑇𝑖𝑖 :Heat transfer losses 𝑓𝑙𝑙𝑙𝑙 :1.06 kg/lπ‘˜π‘˜π‘˜π‘˜ 𝐾333 K (140 F)5%Can be decreased byimproving the k-value!

23 ThermalBeispieltextProcess Engineering for BrewerskronesMashing Which amount of heat is required?𝑄 π‘š β„Žπ‘„ π‘š 𝑐𝑝 Δ𝑇 General equation: Considering mash: Considering π‘š ρ 𝑉𝑄 ρ𝑀 𝑉 𝑐𝑝 (π‘‡π‘œπ‘œπ‘œ 𝑇𝑖𝑖 ) Considering 𝑓𝑙𝑙𝑙𝑙𝑄 ρ𝑀 𝑉 𝑐𝑝 (π‘‡π‘œπ‘œπ‘œ 𝑇𝑖𝑖 ) 𝑓𝑙𝑙𝑙𝑙𝑄 ρ𝑀 𝑉 𝑐𝑝 π‘‡π‘œπ‘œπ‘œ 𝑇𝑖𝑖 𝑓𝑙𝑙𝑙𝑙 1.06Density of mashHeat capacity of mashπ‘˜π‘˜π‘™ 5,800 𝑙 3.6418,310 π‘˜π‘˜ 116.2 π‘˜π‘˜π‘˜π‘˜π‘˜π‘˜π‘˜ 𝐾 351 𝐾 333 𝐾 1.05 Heat capacity of mashVolume of mash10/24/2014 This calculation applies for every infusion-mashing. For more precise calculation, youneed to know your exact material data and you have to find out you transfer losses

24 ThermalBeispieltextProcess Engineering for BrewerskronesMashing What amount of steam do you need to heat up the mash? The heat required from the mash must be served by the steam. Assumingwe work with a saturated steam over pressure of 1 bar (equals 14.5 psi):π‘„π‘šπ‘šπ‘šπ‘š π‘„π‘ π‘ π‘ π‘ π‘ π‘„π‘šπ‘šπ‘šπ‘š π‘šπ‘ π‘ π‘ π‘ π‘  π‘Ÿ1 π‘π‘π‘π‘šπ‘ π‘ π‘ π‘ π‘  π‘„π‘šπ‘šπ‘šπ‘šπ‘Ÿ1 𝑏𝑏𝑏 418,310 π‘˜π‘˜2,206.1 π‘˜π‘˜/π‘˜π‘˜Enthalpy ofcondensation2,206.1 kJ/kg 189.6 π‘˜π‘˜ steam The consideration for the thermal power during heating-up from one rest to another areanalog.10/24/2014Heating ratedetermines thethermal power(and vice versa)Density ofmashHeat flowMass flow ofsaturated steamπ‘„Μ‡π‘šπ‘šπ‘šπ‘š 𝑄̇𝑠𝑠𝑠𝑠𝑠ρ𝑀 𝑉 𝑐𝑝 𝐻𝐻 π‘šΜ‡π‘ π‘ π‘ π‘ π‘  π‘Ÿ1 π‘π‘π‘π‘˜π‘˜π‘˜π‘˜πΎπ‘˜π‘˜1.06 5,800 𝑙 3.6 1 π‘šΜ‡π‘ π‘ π‘ π‘ π‘  2,206.1π‘™π‘˜π‘˜ 𝐾 60π‘ π‘˜π‘˜369 π‘˜π‘˜π‘˜π‘˜π‘˜π‘˜π‘šΜ‡π‘ π‘ π‘ π‘ π‘  0.167 102,206.1 π‘˜π‘˜/π‘˜π‘˜π‘ π‘šπ‘šπ‘šSpecific heatcapacity

25 ThermalBeispieltextProcess Engineering for BrewerskronesWort Boiling Example: External boiling: How often must the wort circulate to achievethe desired evaporation? Assumptions 10/24/2014 The technology ensures an evaporation rate 𝐸 of 6%/hDensity water Οπ‘Šπ‘Šπ‘Šπ‘Šπ‘Š :Density wort Οπ‘Šπ‘œπ‘œπ‘œ :Specific heat 𝑐𝑝,π‘Šπ‘Šπ‘Šπ‘Š :965 kg/m31,030 kg/m34.1π‘˜π‘˜π‘˜π‘˜ 𝐾Density of wort at boiling-temperature. Withincreasing temperature, the density decreases. Boiling-temperature means lower densityTemperature difference Δ𝑇 between in- and outlet of the boiler: 5 KEnthalpy of evaporation π‘Ÿ: 2,250 kJ/kg

26 ThermalBeispieltextProcess Engineering for BrewerskronesWort Boiling Example: External boiling: How often must the wort circulate to achieve thedesired evaporation? The number of cycles is defined by the wort flow and the cast out wort𝑉̇𝑀𝑀𝑀𝑀𝑛 𝑉𝑐𝑐𝑐𝑐 π‘œπ‘œπ‘œ The thermal power of boiling power must be the same as the thermal powerfor evaporation.Density wortHeat capacityHeat flowMust bethe same!10/24/2014 Result:̇𝑄̇𝑏𝑏𝑏𝑏𝑏𝑏 𝑉𝑀𝑀𝑀𝑀 Οπ‘Šπ‘Šπ‘Šπ‘Š 𝑐𝑝,π‘Šπ‘Šπ‘Šπ‘Š ��𝑒 𝑉𝑐𝑐𝑐𝑐 π‘œπ‘œπ‘œ 𝐸 Οπ‘Šπ‘Šπ‘Šπ‘Šπ‘Š π‘ŸThe evaporation rate always refersto the cast out wortEnthalpy of condenstionDensitywaterπ‘˜π‘˜10.06 965 3 2,250 π‘˜π‘˜/π‘˜π‘˜πΈ Οπ‘Šπ‘Šπ‘Šπ‘Šπ‘Š π‘Ÿ1π‘šβ„Žπ‘› 6.2π‘˜π‘˜π‘˜π‘˜Οπ‘Šπ‘Šπ‘Šπ‘Š 𝑐𝑝,π‘Šπ‘Šπ‘Šπ‘Š Ξ”π‘‡β„Ž 5𝐾1,030 3 4.1π‘šπ‘˜π‘˜ 𝐾 7 cycles per hour required!

27 ThermalBeispieltextProcess Engineering for BrewerskronesWort Cooling While cooling down the wort, hot brewing liquor will be gained. For the configuration of a counter-flow plate exchanger, one has toconsider the different temperatures of the water in different parts of thewort cooler.Temperature366 KInlet temperature of the wortΞ”π‘‡π‘šπ‘šπ‘šOutlet temperature of the wort344 K288.5 KOutlet temperature of thebrewing liquorΔ𝑇𝑙𝑙𝑙275 KInlet temperature of the brewing liquorExchange area For that purpose, the average logarithmic temperature Δ𝑇𝑙𝑙𝑙 is used for calculations:10/24/2014Ξ”π‘‡π‘šπ‘šπ‘š Δ𝑇𝑙𝑙𝑙Δ𝑇𝑙𝑙𝑙 Δ𝑇ln( Ξ”π‘‡π‘šπ‘šπ‘š )𝑙𝑙𝑙

28 ThermalBeispieltextProcess Engineering for BrewerskronesWort Cooling Assumptions: The wort gets chilled down from 200 to 60 F (equals 366 to 288.5 K) The brewing liquor’s temperature rises from 36 to 165 F (275 to 344 K) Ξ”π‘‡β„Žπ‘–π‘–π‘– 366 𝐾 344 𝐾 22 𝐾 Δ𝑇𝑙𝑙𝑙 288.5 𝐾 275 𝐾 13.5 𝐾 ln(Ξ”π‘‡β„Žπ‘–π‘–π‘–Ξ”π‘‡π‘™π‘™π‘™) 22 𝐾 13.5 𝐾ln(22 𝐾)13.5 𝐾 17.4 𝐾Required thermal power:ρ𝑀𝑀𝑀𝑀 𝑉𝑐𝑐𝑐𝑐 π‘œπ‘œπ‘œ 𝑐𝑝,𝑀𝑀𝑀𝑀 (𝑇𝑀𝑀𝑀𝑀,𝑖𝑖𝑖𝑖𝑖 𝑇𝑀𝑀𝑀𝑀,π‘œπ‘œπ‘œπ‘œπ‘œπ‘œ )Density wort𝑄̇ Heat capacity𝑐𝑐𝑐𝑐𝑐𝑐𝑐 π‘‘π‘‘π‘‘π‘‘π‘˜π‘˜π‘˜π‘˜ 5,800 𝑙 4.1 (366 𝐾 288.5 𝐾)1.03π‘˜π‘˜ 𝐾𝑙 527.3 π‘˜π‘˜ 3,600 𝑠How much brewing liquor can be gained?𝑄̇ Thermal power527.3 π‘˜π‘˜π‘˜π‘˜π‘šΜ‡π‘€π‘€π‘€π‘€π‘€ 6,550𝑐𝑝,𝑀𝑀𝑀𝑀𝑀 (𝑑𝑀𝑀𝑀𝑀𝑀 π‘œπ‘œπ‘œπ‘œπ‘œπ‘œ 𝑑𝑀𝑀𝑀𝑀𝑀 𝑖𝑖𝑖𝑖𝑖 ) 4.2 π‘˜π‘˜ (344 𝐾 275 𝐾)β„Žπ‘˜π‘˜ 𝐾Heat capacity𝐠𝐠𝐠 𝟏, πŸ•πŸ•πŸ•π‘ 10/24/2014Ξ”π‘‡β„Žπ‘–π‘–π‘– Δ𝑇𝑙𝑙𝑙Δ𝑇𝑙𝑙𝑙

29 ThermalBeispieltextProcess Engineering for BrewerskronesWort Coolin

Brewing & Process Technology Krones Inc Phone: 414 688 7472 Email: Fred.Scheer@kronesusa.com . 2 krones . Thermal Process. Beispieltext Engineering for Brewers . 10/24/2014. Table of Content Why is a Basic Knowledge important for Brewers? Necessary Basics of Thermodynamics Heat and Energy Definition of Thermodynamic Parameters Thermal Energy and Power Heat Transfer How .

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