7.09 ULTRASONIC ANALYZER

Transcription

1 ETHANOL CONCENTRATION MEASUREMENT PAGE 1 OF 6 DENATURANT APPLICATION BLENDING MEASUREMENT % ALCOHOL INTRODUCTION (HOW ETHANOL IS MADE) Ethanol can be produced from a variety of biological sources that contain sugar, starch, or cellulose. 1. Sugar beets and sugar cane are sources of sugar. 2. Wheat and corn are sources of starch. 3. Forest industry waste, grasses or straw, and municipal solid waste contains cellulose. The production process varies, but it usually involves fermentation of sugars by yeast to produce the ethanol. The ethanol is then obtained by fractional distillation. ETHANOL PROPERTIES Ethanol (ethyl alcohol, grain alcohol, and ETOH) Ethanol is denatured to prevent its use as a beverage and mixed with gasoline to form what has been called gasohol. The Rhosonics analyzer measures the alcohol concentration to optimize the blending. The most common blends contain 1% to 10% ethanol and 90% to 99% ethanol mixed with gasoline. COMPOSITION: ETHANOL PROPERTIES CHEMICAL FORMULA: ETHYL ALCOHOL, % BY VOLUME CANADA: CH3CH2OH 98.75% MIN. DENATURANT CANADA*: 100L ETHYL ALCOHOL AND 1L OF UNLEADED GASOLINE ETHYL ALCOHOL, % BY VOLUME USA: 92.1% MIN. DENATURANT USA** (UNLEADED GASOLINE): MIN. OF 1.95% V/V & MIN. OF 4.76% V/V DENSITY 20 C) MAX. * Department of National Revenue Canada ** The American Society for Testing and Materials (standard D for Denatured Fuel, ethanol for blending with gasoline)

2 ETHANOL CONCENTRATION MEASUREMENT PAGE 2 OF 6 PROCESS Ethanol has been made by the fermentation of sugars. During fermentation, yeast converts the sugar to ethanol and carbon dioxide. Yeast changes the simple sugars into ethanol and carbon dioxide. Ethanol is normally concentrated by distillation of aqueous solutions, but the composition of the vapor from aqueous ethanol is 96% ethanol and 4% water. Dehydrating agents can be used to remove the remaining water and produce absolute ethanol. STEPS TO MAKE ETHANOL 1. Milling: The corn (or barley or wheat) will first pas through hammer mills. 2. Liquefaction: The meal will pass through cookers where the starch is liquefied. Heat will then be applied at this stage to enable liquefaction. 3. Saccharification: The mash from the cookers will then be cooled and the secondary enzyme (gluco-amylase) will be added to convert the liquefied starch to fermentable sugars (dextrose). 4. Fermentation: Yeast will then be added to the mash to ferment the sugars to ethanol and carbon dioxide. 5. Distillation: The fermented mash, now call beer, will contain approximately 10% alcohol. The mash will then be pumped to the continuous flow, multi-column distillation system, where the alcohol will be removed from the solids and the water. The alcohol will leave the top of the final column at about 96% strength. The residue mash, called stillage, will be transferred from the base of the column to the co-product processing area. 6. Dehydration: The alcohol from the top of the column will then pass through a dehydration system where the remaining water will be removed. The alcohol product at this stage is called anhydrous (pure, without water) ethanol and is approximately 200 proof. 7. Denaturing: Ethanol that will be used for fuel is then denatured with a small amount (2-5%) of unleaded gasoline. 8. Co-Products: There are two main co-products created in the production of ethanol: carbon dioxide and distiller grain.

3 ETHANOL CONCENTRATION MEASUREMENT PAGE 3 OF 6 WET MILLING OR DRY MILLING There are two distinct process to produce the starch that is converted into sugar: Wet Milling Process (used exclusively for corn) The grain is soaked or steeped to separate and recover the oil before processing. Using this process, corn produces ethanol, carbon dioxide, and a variety of co-products. Wet milling separates corn into its four main parts: starch, germ, fiber, and protein. It is used to produce a variety of primary products such as sweeteners, ethanol, and starch. Gluten meal and gluten feed, both of which are used widely as animal feed. Dry Milling Process grinds the corn to flour and the entire product goes through the fermentation procedure where the starch is converted to ethanol. Dry Milling Process is used to produce ethanol from wheat and other grains. FIGURE 1 - WET MILLING DIAGRAM (

4 ETHANOL CONCENTRATION MEASUREMENT PAGE 4 OF 6 APPLICATION - ALCOHOL MEASUREMENT IN GASOHOL ETHANOL + UNLEADED GASOLINE Distillation-Dehydration After the fermentation alcohol content is 10%, the fermented mash is distilled then the alcohol will be removed from the solids and the water to obtain 96% alcohol content (190 proof alcohol). The alcohol from the top of the column will then pass through a dehydration system where the remaining water will be removed. The alcohol product, at this stage, is called anhydrous (pure, without water) ethanol and is approximately 200 proof. APPLICATION - DENATURANT BLENDING MEASUREMENT % ALCOHOL With the continuous measurement signals of density and sound velocity of the two Rhosonics sensors, the alcohol concentration becomes definable after the unleaded gasoline blending. Measurement The sound velocity with increasing alcohol concentration increases, and the density becomes smaller. With increasing unleaded gasoline concentration increases both values for sound velocity and density. The density sensor measures the density of the unleaded gasoline. The ultrasonic concentration sensor is a highly precise means of determining the sound velocity of the ethanol. Through a product specific calibration that is adjusted to lab analysis, these unleaded gasoline-dependant measured value differences can be compensated. Installation The Rhosonics Analyzer can be located after the injection point of unleaded gasoline (1% to 5%) after the molecular Sieve process.95% to 100% ethanol (200 proof alcohol). 1. The ultrasonic sensor can be mounted directly into the main line. The process connection is supplied in VariVent, Diary fitting DIN 11851, or others upon request. 2. The density sensor is installed in a bypass to the main line with flexible hoses. 3. Based on specific mathematical polynomial calibration curves, the concentrations of alcohol, extract, apparent extract, alcohol content of the ethanol is calculated and used together with the product temperature for controlling different process blending (ie: blending the unleaded gasoline to produce gasohol with concentration from 1% to5%).

5 ETHANOL CONCENTRATION MEASUREMENT PAGE 5 OF 6 ALCOHOL MONITOR DATA DESIGNATION INPUTS Input for ultrasonic MP-54 ultrasonic probe Input for density meter with integral temperature sensors 4-20 ma input for compensation (CO 2 ) Binary input for remote liquid selection SPECIAL CALCULATIONS Conversion of measured parameters into concentrations READOUT OUTPUTS HOUSING AND MISCELLANEOUS On main screen with large characters Concentration alcohol % On detail screen: transit-time, temperature, speed, US temperature, time period, frequency, and density Two independently programmable 4-20 ma outputs for concentrations 2 high-low limit alarms (SPDT, 240 VAC, 3A) RS232 output for output of all measurements ½ - 19" rack mount housing Data interface application for PC & PLC applications For example: Siemens S7-200/300/400 PLC s and others Voltage: VAC SONIC SENSOR ULTRASONIC PROBE With built-in 4-wire PT-100 VariVent process connection A-Septic Material: AISI-316 IP68 Maximum temperature: 302 F DENSITY SENSOR DENSITY PROBE Density: 0 to 3 g/cm 3 (process temperature of cell) Automatic temperature verification Temperature range: -25 to +150 C (-13 F to 302 F) Pressure range: 0 to 50 bar Flowrate (water) 0 to 1000 l/h (0 to 250 gal/h) Accuracy: 5 x 10-5 g/cm 3 - repeatability 1 x 10-5 g/cm 3 Wetted materials: AISI-316L Tube diameter: length I.D. 6.6 mm/500 mm Male 3/8" BSP male parallel thread ISO 228 Overall dimensions: 212 x 360 x 220 mm (W x L x H) Weight: 21 kg CABLE & CONNECTORS MKS-DMT-Es (Instrumentation cable for DMT-Es transmitter) MKS S standard cable set for MP probe Process sample adapter for DMT-ES-8100 Sample take-off and return for density analysis Flexible PTFE lined connecting hose

6 ETHANOL CONCENTRATION MEASUREMENT PAGE 6 OF 6 SONIC ANALYZER (ALCOHOL) DENSITY MEASUREMENT FIGURE 2 - RHOSONICS ALCOHOL ANALYZER IN-LINE