Master Brewer Program (6 Weeks) 1. Fluids fundamentals and equipment. 2. Fluids test. Heat transfer fundamentals and equipment. 3. Heat transfer test. Insulation, steam, refrigeration. 4. Heat exchanger/steam/refrigeration test. Materials, process control. 5. Materials and process control test. Instrumentation, pasteurization, filtration and process gases. 6. Instrumentation, pasteurization, filtration and process gas test. Wrap-up.

How this Relates to the IBD Syllabus 3.1 Packaging Materials 3.2 Unit Packaging Operations 3.3 Sterile Filtration and Pasteurization 3.4 Packaging Line Design 3.5 Quality 3.6 Process Gases 3.7 Fluid Flow 3.8 Principles of Heat Transfer 3.9 Steam 3.10 Refrigeration 3.11 Materials of Construction 3.12 Process Control and Instrumentation

So, what do we need to know about fluids Forms of fluid and fluid energy Properties of moving fluids Friction loss Pumps System design Cavitation and NPSH Valves Qualitative and Quantitative

Liquids – take shape of container, but have finite volume (incompressible) Gases – are compressible, take size and shape of container Shear force will always deform a fluid Mass and volume flow rates Newtonian Fluid – Shear resistance proportional to relative velocity between fluid layers Newtonian – Water, air, beer Non-Newtonian – Gelatin, blood, milk, mash, wort Example: Water with density of 1000 kg/m3 flows through a 10.0 cm diameter pipe at a velocity of 5 m/s. The pipe size is then reduced to a 5.0 cm diameter. Determine the mass and volumetric flow rates and the velocity of the water in the 5.0 cm pipe.

Bernulli’s equation: Applications No-flow Flow through orifice plate, venturi meter “Head” = Pressure Determine the absolute P in the tank using the manometer (water) P Tank 18 cm

Fluid Statics Example: Water fills a 10 m deep tank with a 10 cm diameter butterfly valve at the bottom. Calculate the gauge pressure at the valve and the force acting on the valve, assuming that it is round. Example: Water with density of 1000 kg/m3 flows through a 10.0 cm diameter pipe at a velocity of 5 m/s. The pipe size is then reduced to a 5.0 cm diameter. Determine the mass and volumetric flow rates and the velocity of the water in the 5.0 cm pipe.

Reynolds Number Laminar flow - “low” flow rates, viscous forces most significant Turbulent flow - “high” flow rates, inertial forces most significant Re < 2300Laminar 2300 < Re < 5000Transitional Re > 5000Fully Turbulent

Laminar flow velocity profile (mean / max = 0.5) Turbulent flow velocity profile (mean / max = 0.8)

500 gallons of wort at 70  C is transferred to a boil kettle through a 25 m long, 5 cm diameter pipe. The wort flows at a velocity of 1.2 m/s, the pipe roughness is mm the wort density is 950 kg/m 3 and it’s viscosity is Pa.s. a) Determine the time required to transfer all of the wort to the boil kettle, in min. b) Determine the Reynolds Number. c) Determine the pressure drop in the pipe. d) Would  P change if the wort were at 20  C?

Example E.2 Beer flows in a straight horizontal pipeline, diameter 100 mm such that two sensitive pressure gauges 25 m apart register a pressure difference of 240 Pa (N/m2). The density of the beer is 1.001x10 3 kg/m 3, its viscosity is Ns/m 2 and the relative roughness of the pipe is Calculate the velocity and volumetric flow rate of beer.

Flow Measurement – Oriface Meter C d accounts for frictional loss,  0.65 Simple design, fabrication High turbulence, significant uncertainty P1P1 P2P2

Flow Meas. – Venturi Meter Less frictional losses, C d  0.95 Low pressure drop, but expensive Higher accuracy than orifice plate P1P1 P2P2

Flow Measurement Non-Linear – Venturi, orifice, nozzle meters 4:1 Rangability  2% f.s. accuracy

Flow Meas. – Variable Area/Rotameter Inexpensive, good flow rate indicator Good for liquids or gases No remote sensing, limited accuracy

Flow Measurement - Pitot Tube Direct velocity measurement (not flow rate) Measure  P with gauge, transducer, or manometer P1P1 P2P2 1 2 v

Flow Measurement Magnetic – Faraday’s Law (Conductor moving through magnetic field, voltage produced) 40:1 Rangability  0.5% of f.s. accuracy No obstructions Fluid must conduct No good for Pure water Gases Hydrocarbon fuels External elec/mag fields

Flow Measurement Turbine – magnetic pulse as turbine wheel spins 20:1 Rangability,  0.25% f.s. accuracy Easy to interface with control system

Pumps – Add energy to liquid to move it Pump power output = Pump power input = Pump power requirements include Height fluid must be pumped Friction losses through fittings, equipment Vapor pressure of fluid, tank pressures Total head, NPSH eqations

Pump Sizing Example A pump, located at the outlet of tank A, must transfer 20 m 3 of fluid into tank B in 30 minutes or less. The pipe roughness is mm, and the pump efficiency is 55%. The fluid density is 975 kg/m 3 and the viscosity is Pa.s. The vapor pressure is 10 kPa and the tank is at atmospheric pressure. Determine the total head, pump input and output power and available NPSH. Tank A Tank B 8 m 15 m 4 m Pipe Diameter, 25 mm Fittings = 12 m

Centrifugal Pumps Fluid enters at center and forced radially Open or closed impeller Closed higher efficiency Open handles solids better Advantages Available, cheap, adaptable, simple, reliable Handle wide range of fluids, including solids Discharge can be completely blocked Disadvantages Operate at high speed, high shear stress Limited delivery pressure Cannot meter flow

Positive Displacement Pumps Reciprocating (Piston, Diaphram) Rotary (Gear, peristaltic, lobe) Advantages High delivery pressure Accurate for metering flows Disadvantages Pulsating delivery Tight tolerance, so not good for solids (except for mono pump) Serious damage if discharge valve closed Bigger and more costly for given application

Cavitation Formation of bubbles Pressure drops below vapor pressure (friction losses) Effects Surface pitting and erosion Loss of performance (changed tolerances) High shear stresses Particular concern when pumping wort from kettle to cooler NPSH Required – Pump characteristic NPSH Available – Configuration characteristic

Considerations for Brewery Fluid Handling Multi-component – sugars, proteins, etc. Multi-phase – liquids, solids and/or gases Biologically active – Sensitive to temperature, pressure, pH, contaminants, etc. Sensitive to oxygen Surface area exposed, still or wavy Temperature and pressure Avoid less than full flow Avoid filling tanks from the top Sensitive to shear forces

Centrifugal Pumps – Principle of Operation Impeller Suction Volute Casting Delivery

Centrifugal Pumps – Principle of Operation Flow accelerated (forced by impeller) Then, flow decelerated (pressure increases) Low pressure at center “draws” in fluid Pump should be full of liquid at all times Flow controlled by delivery side valve May operate against closed valve Seal between rotating shaft and casing

Centrifugal Pumps – Impeller Designs Closed Impeller Most common, few solids Water, beer, wort Flash pasteurization Secondary refrigerants Open Impeller Lower pressures Solids okay Mash mixer to lauter tun Liquid yeast, wort, hops

Centrifugal Pumps Materials - Can be made of many materials What do you think is used in brewery? Shaft seal – Must seal between rotating shaft and volute casting, effects efficiency Hygiene Considerations – No valves, crevices, can be CIP. Mechanical seal between two faces (impeller shaft and volute casting) faces kept together with spring.

Centrifugal Pumps Control – Valve on delivery side or change pump speed (not always available, “VFD”) Self-Priming – Centrifugal pump will not work when “air-bound.” Can self-prime by supplying a reservoir with a “bleed supply” of liquid. Air from pipework and liquid from reservoir moves through pump until it is flooded by liquid from suction pipework. Used for CIP fluid return.

Centrifugal Pumps Multiple pumps connected in series required for high pressures (flash pasteurization) Curves created for specific speed, viscosity and density Variable speed motor has same effect as impeller size Multiple pump/impeller combinations may work

Centrifugal Pumps H-Q Chart Head (or  P) Volume Flow Rate Increasing Impeller Diameter A B C

Centrifugal Pumps H-Q Chart Head (or  P) Volume Flow Rate A B C Increasing Efficiency Required NPSH

Centrifugal Pumps H-Q Chart Head (or  P) Volume Flow Rate A B C

Centrifugal Pumps H-Q Chart Head (or  P) Volume Flow Rate Required Flow Capacity Actual Flow Capacity Required Power

Centrifugal Pumps Advantages Simple construction, many materials No valves, can be cleaned in place Relatively inexpensive, low maintenance Steady delivery, versatile Operates at high speed (electric motor) Wide operating range (flow and head) Disadvantages Multiple stages needed for high pressures Poor efficiency for high viscosity fluids Must prime pump

Positive Displacement Pumps Theory: Volume dispensed independent of delivery head Practice: As delivery head increases, some slippage or leakage occurs Speed used to control flow rate, use of valves could cause serious damage Self-priming Good for high viscosities, avoiding cavitation

Positive Displacement Pumps Piston Pump Volumetric EfficiencyHigh Pressures Metering hop compounds, detergents, sterilents Suction Valve Delivery Valve

Positive Displacement Pumps Diaphragm Pump – Similar to piston pump, diaphragm contacts fluid Not as accurate as piston pump, particles okay Transfer trub, yeast, tank bottoms Suction Valve Delivery Valve

Positive Displacement Pumps Peristaltic Pump Tubing compressed in stages Hygienic, easily cleaned (new tubing) Can be run dry Laboratory applications, sampling, dosing

Positive Displacement Pumps Gear Pump High Pressures No Pulsation High Viscosity Fluids No Solids Difficult to Clean Not common in brewery, oil feed to boiler

Positive Displacement Pumps Lobe Rotor Pump Both lobes driven Can be sterilized (steam) Transfer Yeast Trub Bulk Sugar Syrup

Positive Displacement Pumps Screw or Mono Pump Helical worm rotates inside elastomeric stator Seal between worm and stator Fluid is forced downstream Variety of fluids, slurries. Cannot be steam sterilized, cannot run dry Used to transfer yeast and trub slurries Flexible Vane Pump Flexible rubber impeller rotates Sampling and dosing detergents, sterilents

Centrifugal Pumps Fluid enters at center and forced radially Open or closed impeller Closed higher efficiency Open handles solids better Advantages Available, cheap, adaptable, simple, reliable Handle wide range of fluids, including solids Discharge can be completely blocked Disadvantages Operate at high speed, high shear stress Limited delivery pressure Cannot meter flow

Positive Displacement Pumps Reciprocating (Piston, Diaphram) Rotary (Gear, peristaltic, lobe) Advantages High delivery pressure Accurate for metering flows Disadvantages Pulsating delivery Tight tolerance, so not good for solids (except for mono pump) Serious damage if discharge valve closed Bigger and more costly for given application

Pump Selection Considerations Head and flow requirements Characteristics of fluid (density, viscosity, etc.) Materials (sterilization, erosive nature of slurries) Crevices where solids can accumulate Hygienic design, seals Pressure relief Interchangability (spares) Cavitation and NPSH What causes cavitation? What are the effects of cavitation? Factors that cause cavitation? NPSH Available vs. NPSH Required Particular problems for breweries

Centrifugal Pumps What if available NPSH is less than required NPSH? Increase Available NPSH 1. Increase suction static head (pump location) 2. Increase suction side pressure 3. Decrease fluid vapor pressure 4. Reduce friction losses on suction side Decrease Required NPSH 1. Reduce pump speed 2. Select a different pump

Valves – Globe Valve Single Seat - Good general purpose - Good seal at shutoff Double Seat - Higher flow rates - Poor shutoff (2 ports) Three-way - Mixing or diverting - As disc adjusted, flow to one channel increased, flow to other decreased

Valves – Butterfly Valve Low Cost “Food Grade” Poor flow control Can be automated

Valves – Mixproof Double Seat Valve Two separate sealing elements Keeps fluids from mixing Immediate indication of failure Automated, Sanitary apps Easier and Cheaper than using many separate valves

Valves – Gate Valve Little flow control, simple, reliable

Valves – Ball Valve Very little pressure loss, little flow control

Other Valves Diaphram – Flexing membrane Non-return – Flow in one direction only Applications Product - Butterfly and mix-proof common, diaphram. Hygiene critical. Service – Butterfly, globe, gate, ball. High temperature, pressure. Flow control – Globe, modified globe and modified butterfly. Pressure reduction – Spring loaded pressure reducing valve. Often for steam. Pressure relief – Spring or weight loaded.

Valves – Considerations Duty – What the valve is designed to do (on/off, product routing, pressure reduction, etc.) Process – Corrosion of valve body, seals Temperature – Closed valve, solidifying product Pressure – Max and min, do not overpressure Capacity – Flow for given pressure Leakrate – Maximum allowable leakage Connections – Flanges, NPT, tubing, hose, etc. Actuator – Torque, fail open or closed Feedback – Signal indicating valve’s position

Valves in Breweries Product Routing – Tight shut-off, CIP, material compatibility (elastomer seals). Butterfly and mixproof common. Service Routing – Tight shut-off, high temperature and pressure. Globe, gate, ball. Flow Control Water temperature control Steam flow rate control in wort boiling Fermentation vessel temperature control tank gas top pressure control CO2 addition during in-line carbonation water addition during high gravity brewing

So, what do we need to know about fluids Forms of fluid and fluid energy Properties of moving fluids Friction loss Pumps System design Cavitation and NPSH Valves Qualitative and Quantitative

Readings for Next Week BS+T – Chapter 1 (if you don’t read anything else, read this) Singh – Chapter 2 Kunze – , 6.1.2, 6.1.3, 3.3.3, 3.3.4