:__ / C. OREGON COLLLCTlop Improvements in The Field Distillation of Peppermint Oil By A. D. HUGHES Professor of Mechanical Engineering Bulletin No. 31 August 1952 A Cooperative Research Project of the Engineering Experiment Station and the Agricultural Experiment Station. Engineering Experiment Station Oregon State College Corvallis THE Oregon State Engineering Experiment Station was established by act of the Board of Regents of Oregon State College on May 4, 1927. It is the purpose of the Station to serve the state in a manner broadly outlined by the following policy: (1)To stimulate and elevate engineering education by developing the research spirit in faculty and students. (2) To serve the industries,utilities, professional engi- neers, public departments, and engineering teachers by making investigations of interest to them. (3) To publish and distribute by bulletins, circulars, and technical articles in periodicals the results of such studies, sur- veys, tests, investigations, and research as will be of greatest benefit to the people of Oregon, and particularly to the state's industries, utilities, and professional engineers. To make available the results of the investigations con- ducted by the Station three types of publications are issued. These are: (1) Bulletins covering original investigations. (2) Circulars giving compilations of useful data (3) Reprints giving more general distribution to scientific papers or reports previously published elsewhere, as for exam- ple, in the proceedings of professional societies. Single copies of publications are sent free on request to residents of Oregon, to libraries, and to other experiment sta- tions exchanging publications.As long as available, additional copies, or copies to others, are sent at prices covering cost of printing. The price of this publication is 60 cents. For copies of publications or for other information address Oregon State Engineering Experiment Station, Corvallis, Oregon Improvements in The Field Distillation of Peppermint Oil By A. D. HUGHEs Professor of Mechanical Engineering BULLETIN NO. 31 AUGUST 1952 A Cooperative Research Project of the Engineering Experiment Station and the Agricultural Experiment Station Engineering Experiment Station Oregon State College Corvallis This report also published as Agricultural Experiment Station Bulletin 525. TABLE OF CONTENTS Page FOREWORD AND ACKNOWLEDGMENTS ........5 I. INTRODUCTION.... 7 1. Objectives of the Project------------------------------------------------------------------------ 7 2. Production and Uses of Peppermint Oil-------------------------------------------- 8 3. Characteristics of Peppermint Oil-------------------------------------------------------- 8 4. Field Distillation Process------------------------------------------------------------------------ 8 II. FIELD DISTILLATION UNITS--------------------------------------------------------------10 1. Typical Plants in Oregon----------------------------------------------------------------------10 a. Plant with Stationary Tub, Open Drip-Type Condenser----------10 b. Plant with Portable Tub, Submerged Condenser------------------------12 2. Redistillation Unit------------------------------------------------------------------------------------12 3. Mint Still Survey----------------------------------------------------------------------------------------14 4. Tests on Field Distillation Units----------------------------------------------------------15 a. Helms Plant, near Jefferson, Oregon----------------------------------------------16 b. Davidson-Kieper Plant, near Talbot, Oregon------------------------------19 c. Earl Chartrey Plant, Clatskanie ------------------------------------------------------23 d. Heat Wastage----------------------------------------------------------------------------------------28 III. PILOT PLANT DESIGN AND CONSTRUCTION--------------------------29 1.Need foraPilot Plant----------------------------------------------------------------------------29 2. Design Basis------------------------------------------------------------------------------------------------29 3. Laboratory Tests--------------------------------------------------------------------------------31 4.Method of Construction----------------------------------------------------------------------------32 5.Selection and Operation of Instruments and Controls--------------------32 6. Tests on Baled Hay----------------------------------------------------------------------------------33 IV. FIELD TESTS WITH PILOT PLANT------------------------------------------------35 1.Selection of Problems for Investigation----------------------------------------------35 2. Long vs Chopped Hay------------------------------------------------------------------------------36 3.Effect of Time of Drying (or Curing)----------------------------------------------36 4.Partial Loads of Hay--------------------------------------------------------------------------39 5.The Pilot Plant as a Redistillation Unit--------------------------------------------40 V. STUDY OF THE MINT OIL SEPARATION PROCESS------------ 40 1. Effect of Velocity and Temperature----------------------------------------------------41J 2.Laboratory Tests with the Glass Separating Can----------------------------42 3.Basis for Design of Baffled Separator--------------------------------------------------45 4.Operation of the Opti-Stopper----------------------------------------------------------------46 VI. RECOMMENDATIONS AND CONCLUSIONS..............................47 1. Recommendations --------------------------------------------------------------------------------------47 2. Conclusions ---------------------------------------------------------------------------------------------So VII. BIBLIOGRAPHY ----------------------------------------------------------------------------------------- So TABLE OF CONTENTS (Continued) Page VIII. APPENDIX 1. Physical and Thermal Tests on Peppermint Oil -------------------------------ci a. Distillation Tests ---------------------------------------------------------------------ci 51 b. Demulsibility -------------------------------------------------------------------------------------- c. Vaporization Loss at Various Temperatures --------------------------------- d. vapor Pressure Determination 53 56 e. Viscosity---------------------------------------------------------------------------------------------- 56 f. Specific Gravity -------------------------------------------------------------------------------- g. Centrifugal Separation of Peppermint Oil from Water -------------58 11. Solubility of Peppermint Oil in Water ------------------------------------------58 i. Corrosion Tests------------------------------------------------------------------------------------59 ILLUSTRATIONS Figure 1. Field Distillation Unit with Stationary Tub and Open Drip TypeCondenser --------------------------------------------------------------------------------------------------II Figure 2.Field Distillation Unit with Rectangular Portable Tub and Submerged Condenser ----------------------------------------------------------------------------------------13 Figure 3.Helms Plant near Jefferson, Oregon ------------------------------------------------------16 Figure 4.Log of Normal RunHelms Plant ------------------------------------------------------17 Figure 5.Log of Test Run with Steam Cut BackHelms Plant --------------------20 Figure 6.Log of Normal RunDavidson-Kieper Plant ------------------------------------22 Figure 7.Log of Test Run witl1 Steam Cut BackDavidson-Kieper Plant23 Figure 8.Plant of Earl Chartrey, Clatskanie --------------------------------------------------------24 Figure 9.Log of Normal RunChartrey Plant ----------------------------------------------------25 Figure 10.Log of Test Run with Steam Cut BackChartrey Plant --------------27 Figure 11.Schematic Flow Diagram of Pilot Plant ------------------------------------------30 Figure 12.Pilot Plant in Operation at Dale Turnidge Farm, Jefferson --------33 Figure 13.Test Set-UI) Using Glass Separator ----------------------------------------------------42 Figure 14.View through Glass Separating Can ----------------------------------------------------44 Figure 15.Effect of Baffle in Glass Separating Can 44 Figure 16.Sectional View of Baffle Separator with Opti-Stopper ------------------45 Figure 17.Distillation Curves for Peppermint Oil ----------------------------------------------- Figure 18.Demulsibility of Prime Peppermint Oil in Water ---------------------------54 Figure 19.Vaporization Loss of Peppermint Oil at Various Temperatures55 Figure 20.Viscosity of Peppermint Oil -------------------------------------------------------------------57 LIST OF TABLES Table 1. Typical Physical and Chemical Properties of Oregon Oils -------------- 9 Table 2. Effect of Curing Time on Long and Chopped Hay ---------------------------- 38 Table 3. Effect of Depth of Load ------------------------------------------------------------------------------ 39 4 FOREWORD and ACKNOWLEDGMENTS The experimental work reported in this bulletin was performed by Professor A. D. Hughes as a joint project of the Engineering Experiment Station and the Agricultural Experiment Station at Ore- gon State College, Corvallis, Oregon.The project was under the supervision of S. H. Graf, Director of the ingineering Experiment Station, and N. S. Besse, Associate Director of the Agricultural Ex- periment Station. This work was made possible largely through a financial grant by the William J. Wrigley, Jr Company