Experimentally Investigating the Thermal Effects of Cross Flow Corn Drying

2012 ◽  
Author(s):  
Stephen P. Gent ◽  
Michael P. Twedt ◽  
Chad R. Abrahamson
Keyword(s):  
Thermal Effects ◽  
Crop Yields ◽  
Cross Flow ◽  
Packed Bed ◽  
The United States ◽  
Pilot Scale ◽  
High Energy ◽  
Operating Conditions ◽  
Column Height ◽  
Grain Drying

This study measured the thermal effects of corn drying within a continuous cross-flow grain dryer based on a variety of operating conditions. The dryer contains a column of grain that acts as a packed bed in which the air flows through the voids between the kernels. The study analyzed the following parameters and their effects on corn drying: dryer column thickness, air flow rate per volume of corn, air drying temperature, and incoming and outgoing corn moisture. A pilot-scale cross flow corn dryer with variable column thickness, variable drying air temperature, and variable fan speed was used to experimentally dry corn. The pilot scale dryer has a drying column height of 3.35 m (132 in.), column width of 0.61 m (24 in.) and a variable thickness of 0.203 m to 0.305 m (8 to 12 in.). An array of thermocouples was arranged through the packed bed of corn to measure the thermal profile as the air propagated through the corn. The thermal profiles from the experiments were compared and evaluated among the experiments. In the United States, corn is a primary grain commodity. Improved farming practices, in conjunction with improved grain genetics, have resulted in increased grain yields and the ability to grow crops in locations not possible two decades prior. After harvesting, most grains require supplemental drying to prevent spoilage. Continuous flow grain dryers have become a common method of drying and conditioning large amounts of grain. Grain dryers are required to dry grain faster and more efficiently without sacrificing grain quality. However, higher energy costs and increased crop yields have made grain drying the second largest expense for grain producers due to their high energy consumption of propane or natural gas. The overarching goal of this study is to determine the primary factors that influence heat propagation within the packed bed of grain with the intention of incorporating these effects into numerical grain drying models.

Performance of a pilot-scale cross-flow rotating packed bed in removing VOCs from waste gas streams

2006 ◽  
Vol 52 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Chia-Chang Lin ◽  
Tzu-Ying Wei ◽  
Shu-Kang Hsu ◽  
Wen-Tzong Liu
Keyword(s):  
Cross Flow ◽  
Packed Bed ◽  
Pilot Scale ◽  
Waste Gas ◽  
Gas Streams ◽  
Rotating Packed Bed ◽  
Waste Gas Streams

Experimental Investigation of a Lab-Scale, Cross-Flow Grain Dryer for Testing of Drying Efficiency and Characteristic Profiles of a Packed Bed

2015 ◽  
Author(s):  
Taylor N. Suess ◽  
Michael P. Twedt ◽  
Stephen P. Gent
Keyword(s):  
Energy Use ◽  
Cross Flow ◽  
Electric Heating ◽  
Packed Bed ◽  
Operating Conditions ◽  
Heating Process ◽  
Air Temperatures ◽  
Two Factors ◽  
Forced Air ◽  
Drying Efficiency

This study investigates the drying mechanisms of corn when it is exposed to air at elevated temperature and velocity within a cross-flow packed bed dryer. A highly-instrumented laboratory-scale experimental test dryer was constructed to batch-dry samples of 0.03 m3 (1 ft3) of high moisture corn. This is achieved using a perforated wall drying chamber with forced air at temperatures ranging from 180–240°F. The high temperature, high velocity air entering the column is supplied by a variable speed fan and a variable Wattage electric heating coil through a 0.09 m2 (1 ft2) square air duct. This device is able to precisely control the drying air temperate and flow rate, while also measuring the temperature and humidity of the air exiting the dryer. In creating and instrumenting this apparatus, tests were performed to analyze both energy use and drying rate to determine the operating conditions that find a balance between energy and time requirements for moisture removal. This study used a variety of supply air temperatures and air flow rates in drying samples of corn at two initial moisture contents (19%MC and 24%MC) to 15%MC. This is done to determine if there are notable differences in energy requirements (Btu/pound water removed) between different operating conditions. This study determined that corn undergoes a significant pre-heating process before peak drying efficiency is achieved. Current grain dryer designs should focus the most energy just after that pre-heating process for highest overall efficiencies. Additionally, this study found an inverse relationship between dry time and energy efficiency, which showed that an optimum balance between those two factors should be identified.

Comparison of Theoretical and Experimental Corn Drying Profiles Within a Cross-Flow Column Dryer

2013 ◽  
Author(s):  
Lars M. Mattison ◽  
Taylor N. Suess ◽  
Michael P. Twedt ◽  
Stephen P. Gent
Keyword(s):  
Cross Flow ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Ambient Conditions ◽  
Key Factors ◽  
Air Velocity ◽  
Corn Production ◽  
Drying Characteristics ◽  
Exhaust Temperature ◽  
Fan Speed

This study compared the drying characteristics of corn within a continuous flow dryer under a variety of operating conditions. The tests were completed on a pilot scale cross flow corn dryer with variable fan speed and column thickness. The dryer column has a height of 3.35 m (132 in.), width of 0.61 m (24 in.) and variable thicknesses ranging from 0.30–0.36 m (12–14 in.). In addition, the drying air temperature and air flow rate per volume of grain were varied. An array of thermocouples measured the thermal profile of the corn bed within the dryer. The dryer exhaust was divided into four zones, each 0.83 m (33 in.) tall. Each zone measured incoming air velocity and exhaust temperature and relative humidity. Using these measured values in conjunction with the known ambient conditions, the theoretical amount of moisture removed from each zone was calculated. Corn dryer efficiency and throughput are becoming increasingly important, as it is the second largest cost associated with corn production. Improved farming practices, in conjunction with improved corn genetics, have resulted in increased yields and the ability to grow corn in locations not possible two decades prior. The overarching goal of this research is to help determine the key factors which help to dry corn more efficiently.

Creating an Application to Predict Operational Characteristics and Efficiency of Continuous Cross-Flow Corn Drying

2013 ◽  
Author(s):  
Matthew L. Olson ◽  
Stephen P. Gent ◽  
Taylor N. Suess ◽  
Michael P. Twedt
Keyword(s):  
Cross Flow ◽  
Ease Of Use ◽  
Operating Conditions ◽  
Operational Characteristics ◽  
Grain Drying ◽  
Improve Accuracy ◽  
Drying Models ◽  
Drying System ◽  
Page Equation ◽  
Drying Conditions

The purpose of this study is to create a computer simulation which numerically predicts the drying conditions within a continuous cross-flow grain drying system. The model is based on a system of four partial differential equations using energy and mass balances for the air, grain, and moisture within the column. This simulation includes: (1) a graphical user interface for varying the operating conditions, (2) a numerical scheme for solving the system of equations based on a backwards finite difference scheme, and (3) graphical and tabular output data. The output includes graphs of moisture content, air temperature, and grain temperature inside the column, as well as the predicted energy consumption of the system. Using this program, the grain drying model is analyzed in order to gain insight towards the optimal operating conditions for the grain dryer. The study also makes adjustments to the model in order to improve accuracy and ease of use. In particular, the Page equation for single-kernel drying is implemented. Model assumptions are also analyzed for validity, and the solutions are verified using experimental data collected in a previous study. The overall goal of this research is to improve grain dryer design and optimize operating conditions in order to reduce energy costs, improve grain quality, and increase the understanding of deep bed grain drying models.

Future Needs in Weed Science

Weed Science ◽  
1984 ◽  
Vol 32 (6) ◽  
pp. 850-855 ◽  
Author(s):  
C. G. McWhorter
Keyword(s):  
United States ◽  
Weed Control ◽  
Agricultural Production ◽  
Crop Yields ◽  
The United States ◽  
Grain Drying ◽  
Direct Competition ◽  
The Cost ◽  
And Storage

Losses due to weeds in the United States and the cost of their control are now more than $20 billion annually (35). Of this total, $13 billion represents a 10% annual loss in agricultural production that includes not only the direct competition of weeds to reduce crop yields but also the reduced quality of produce, livestock losses, and increased cost of fertilizer, irrigation, harvesting, grain drying, transportation, and storage. In addition, farmers spend more than $7.2 billion to control weeds each year. About 43% of the expenditures to control weeds is the retail cost of herbicides, $3.1 billion, in 1980 (15). The value of herbicides sold in 1984 will probably be about 15% higher than in 1980. An additional $4.1 billion represents the cost of tillage and hand labor required for weed control (35). The total loss of over $20 billion represents an indirect annual weed tax of about $85 on each individual living in the United States.

Application of a Pilot-Scale Pulsed Electrocoagulation system to OCC-Based Paper Mill Effluent

TAPPI Journal ◽  
2009 ◽  
Vol 8 (3) ◽  
pp. 14-20 ◽  
Author(s):  
YUAN-SHING PERNG ◽  
EUGENE I-CHEN WANG ◽  
SHIH-TSUNG YU ◽  
AN-YI CHANG
Keyword(s):  
Water Quality ◽  
Quality Indicators ◽  
Paper Mill ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Optimal Dosage ◽  
Water Quality Indicators ◽  
Paper Mill Effluent ◽  
Treated Effluent ◽  
True Color

Trends toward closure of white water recirculation loops in papermaking often lead to a need for system modifications. We conducted a pilot-scale study using pulsed electrocoagulation technology to treat the effluent of an old corrugated containerboard (OCC)-based paper mill in order to evaluate its treatment performance. The operating variables were a current density of 0–240 A/m2, a hydraulic retention time (HRT) of 8–16 min, and a coagulant (anionic polyacrylamide) dosage of 0–22 mg/L. Water quality indicators investigated were electrical con-ductivity, suspended solids (SS), chemical oxygen demand (COD), and true color. The results were encouraging. Under the operating conditions without coagulant addition, the highest removals for conductivity, SS, COD, and true color were 39.8%, 85.7%, 70.5%, and 97.1%, respectively (with an HRT of 16 min). The use of a coagulant enhanced the removal of both conductivity and COD. With an optimal dosage of 20 mg/L and a shortened HRT of 10 min, the highest removal achieved for the four water quality indicators were 37.7%, 88.7%, 74.2%, and 91.7%, respectively. The water qualities thus attained should be adequate to allow reuse of a substantial portion of the treated effluent as process water makeup in papermaking.

Pilot-scale combustion studies with kraft lignin in a powder burner and a CFB boiler

TAPPI Journal ◽  
2010 ◽  
Vol 9 (6) ◽  
pp. 24-30 ◽  
Author(s):  
NIKLAS BERGLIN ◽  
PER TOMANI ◽  
HASSAN SALMAN ◽  
SOLVIE HERSTAD SVÄRD ◽  
LARS-ERIK ÅMAND
Keyword(s):  
Circulating Fluidized Bed ◽  
Black Liquor ◽  
Chloride Content ◽  
Pilot Scale ◽  
High Energy ◽  
Kraft Lignin ◽  
High Energy Density ◽  
Alkali Chloride ◽  
Cfb Boiler ◽  
Solid Biofuel

Processes have been developed to produce a solid biofuel with high energy density and low ash content from kraft lignin precipitated from black liquor. Pilot-scale tests of the lignin biofuel were carried out with a 150 kW powder burner and a 12 MW circulating fluidized bed (CFB) boiler. Lignin powder could be fired in a powder burner with good combustion performance after some trimming of the air flows to reduce swirl. Lignin dried to 10% moisture content was easy to feed smoothly and had less bridging tendencies in the feeding system than did wood/bark powder. In the CFB boiler, lignin was easily handled and cofired together with bark. Although the filter cake was broken into smaller pieces and fines, the combustion was not disturbed. When cofiring lignin with bark, the sulfur emission increased compared with bark firing only, but most of the sulfur was captured by calcium in the bark ash. Conventional sulfur capture also occurred with addition of limestone to the bed. The sulfur content in the lignin had a significantly positive effect on reducing the alkali chloride content in the deposits, thus reducing the high temperature corrosion risk.

A pilot web former designed to study retention-formation relationships

2010 ◽  
Vol 25 (2) ◽  
pp. 185-194
Author(s):  
Anna Svedberg ◽  
Tom Lindström
Keyword(s):  
Pilot Scale ◽  
Operating Conditions ◽  
Montmorillonite Clay ◽  
Speed Ratio ◽  
Good Reproducibility ◽  
Total Solids ◽  
Retention Aids ◽  
Solids Content ◽  
Relationship Of ◽  
The Relationship

Abstract A pilot-scale fourdrinier former has been developed for the purpose of investigating the relationship between retention and paper formation (features, retention aids, dosage points, etc.). The main objective of this publication was to present the R-F (Retention and formation)-machine and demonstrate some of its fields of applications. For a fine paper stock (90% hardwood and 10% softwood) with addition of 25% filler (based on total solids content), the relationship between retention and formation was investigated for a microparticulate retention aid (cationic polyacrylamide together with anionic montmorillonite clay). The retention-formation relationship of the retention aid system was investigated after choosing standardized machine operating conditions (e.g. the jet-to-wire speed ratio). As expected, the formation was impaired when the retention was increased. Since good reproducibility was attained, the R-F (Retention and formation)-machine was found to be a useful tool for studying the relationship between retention and paper formation.

Nanofiltration of colored surface water: Quebec's experience

2003 ◽  
Vol 3 (5-6) ◽  
pp. 15-22
Author(s):  
P. Kouadio ◽  
M. Tétrault
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Quebec City ◽  
Water Regulation ◽  
Eastern Canada

Three colored surface water nanofiltration pilot-scale projects were conducted in the province of Quebec (eastern Canada), between November 2000 and March 2002, by the company H2O Innovation (2000) inc., for the municipalities of Lac Bouchette, Latulipe-et-Gaboury and Charlesbourg (now part of Quebec City). Results indicated that nanofiltration permeate quality has an advance on present drinking water regulation standard in Quebec, but important membrane fouling occurred. Fouling can be controlled by pretreatment and optimization of the operating conditions.

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