Spray Dryers

The AMERICAN INSTITUTE OF CHEMICAL ENGINEERS (AIChE) is a distinguished professional association that strives to provide leadership in the advancing chemical engineering profession. The Equipment Testing Procedures Committee is composed of engineers with substantial experience in the design and operation of process plants, as well as in solving problems that can arise with the equipment used in these plants.

Purpose and Scope. Purpose.

Purpose.

Summary.

Scope of Spray Drying.

Reasons for Testing Spray Dryers.

Design vs. Operational Variables.

Liability.

Definitions and Descriptions of Terms.

Dryer Design.

Dryer Chamber.

Airflow Patterns.

Product Flow.

Atomizer.

Heating Methods.

Product Recovery.

Airflow Motive Force.

Description of Terms.

Drying.

Test Planning.

Preliminary Objectives.

Test Objectives.

Test Objectives.

Organizational Resources.

Schedule.

Dryer Controls and Instrumentation.

Peripheral Equipment.

Pretest Calculations.

Test Plan.

Environmental.

Cleaning and Inspection.

"Dry Run".

Types of Test.

Dryer System Capacity.

Heat and Material Balance.

Product Properties.

Acceptance Test.

Variables Affecting Product Properties.

Residual Moisture Content.

Atomization.

Heat Sensitivity.

Physical Properties.

Prediction of Capacity and Rate Effects.

Summary.

Data Requirements - Product Properties.

Data Requirements.

Atomizer Data.

Complete Heat and Material.

Balances.

Peripheral Equipment Limitations.

Product Quality Measurements.

Particle Properties.

Test Preparation.

Objective of Tests.

Operating Variables.

Test Data Sheet.

Measurement Methods.

Test Plan.

Planning Check List.

Methods of Measurement and Sampling.

Gas Temperature Humidity.

Selection of Temperature Sensors.

Installation of Temperature Sensors.

Duct Temperature and Velocity Profiles.

Accuracy of Dry Bulb Temperatures.

Atmospheric Humidity.

Dryer Exit Humidity.

Accuracy of Gas Wet Bulb Temperature.

Gas Flow.

Installed Flow Meters.

Inlet Gas.

Exit Gas Measurement.

Material Temperature and Moisture Content.

Product Temperature Measurement.

Product Moisture Content.

Dust Flow Measurements.

Radiation and Convection Heat Losses.

Estimated Heat Loss.

Measuring Heat Loss.

Outdoor Equipment.

Miscellaneous Measurements.

Static Pressure.

Location of Pressure Sensors.

Electric Power Measurements.

Test Procedure.

Plant-Scale Test.

Exploratory Experiments.

Production Capacity.

Product Quality.

Preliminary Trial.

Water Run.

Dryer Operability.

Definitive Test.

Test Start-Up.

Running a Definitive Test in a Plant-Scale Dryer.

Humidity and Moisture Measurements.

Computation of Results.

Nomenclature.

Variables.

Properties.

Subscripts.

Material Balances.

Dry Solids.

Moisture balance.

Psychrometric Chart Method.

Humid Air Volume.

Total Air Volume.

Air Material Balance.

Heat Balances.

Enthalpy or Heat Balances on the Dryer.

Heater Balances.

Thermal Efficiency.

Calculation.

Optimization.

Interpretation of Results.

Exploratory or Troubleshooting Tests.

Material, Moisture, and Energy Balances.

Dryer Heat Losses and Thermal Efficiency.

Heat Losses.

Thermal Efficiency.

Appendix.

Nomenclature.

Example: Evaluating Drying Capacity of Air Stream.

Example: Dryer Test With Psychrometric Chart Heat Balance.

Known Inputs.

Evaluate Product and Evaporation Rate.

Ambient Air Humidity, Enthalpy, and Humid Volume.

Humidity Added by Fuel.

Combustion.

Dryer Outlet Conditions.

Dry Air Flow Rate.

Total Air Flow Rates.

Burner Heat Input.

Check Driving Force for Evaporation.

Example: Typical Dryer Test.

Experimental Data.

Humidities (H).

Air Flows - Outlet.

Air Flows - Inlet.

Dry Solids Balance.

Moisture Balance.

Moisture Balance - Evaporation Rates.

Heat Balances: Heat Duty and Fuel Consumption.

Heat Balance Over Dryer.

Thermal Efficiency.

Adiabatic Saturation.

Test Data Sheet.

Psychrometric Chart.

Index.

References.

Tables and Figures.