“Economics of Oversized Cyclones in the Cotton Ginning Industry”
(1) Sergio Sotelo, Undergraduate Student, Dept. of Ag economics & and Ag Business, New Mexico State University. E-mail:
(2) Ram N. Acharya, Associate Professor, Dept. of Ag Econ & Ag Business, New Mexico State University. E-mail:
(3) Paul Funk, Southwest Ginning Lab, USDA. E-mail:
Selected Paper prepared for presentation at the Southern Agricultural Economics Association’s 2015 Annual Meeting, Atlanta, Georgia, January 31-February 3, 2015
Copyright 2015 by [authors]. All rights reserved. Readers may make verbatim copies of this document for non-commercial purposes by any means, provided that this copyright notice appears on all such copies.
Abstract
Cost of reducing pollution to meet increasingly stringent air quality standards particularly for the U.S. cotton ginning industry is rising overtime. Most industry participants use cyclones to control air pollutants. These cyclones have no moving parts and their initial investment costs are relatively low. However, they require a substantial amount of energy to run them. Since the electricity rates are rising, the ginning industry is constantly looking for opportunities to increase cyclone operating efficiency and reduce the cost of complying with the local, state, and federal air pollution standards. Dust particles of size PM10 and PM2.5 are the pollutants of main concern for the industry. Researchers in the USDA’s Southwest Ginning Lab in Las Cruces are conducting experiments to evaluate whether using bigger diameter cyclones at lower inlet velocities can reduce the energy costs. If these experiments show that the bigger diameter cyclones can achieve the same level of air pollution control, it may substantially reduce energy cost and boost ginning industry profitability. This study uses the results from the ginning lab to evaluate the impact of using bigger cyclones at lower inlet velocity to reduce energy use, decrease emission, and increase profitability of the ginning industry.
Due to arising electricity rates, effective cyclone operating strategies have been sought for cotton gins to control particulate emissions using less energy with current cyclone technology. Tests were conducted in the Cotton Ginning Laboratory of the Agricultural Research Service in Las Cruces, NM with 60 in and 72 in diameter cyclones at inlet velocities of 9.5-16.5 ms using cotton gin trash as a test material at loadings of 5-75gm3. These experiments intended to prove efficiency at controlling PM emissions by the implementation of oversized cyclones.
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Figure 4
Based on the results obtained, we can assume that more particulate matter is emitted when the inlet velocity increases; while the emission of PM decreases in heavier loads. According to Baker Et. Al, cyclone collection efficiency increases as trash loading rate increases, with average values ranging from 97.94% at a trash−loading rate of 2 g/m3 (0.88 grain/ft3) to an average of 98.96% at a trash−loading rate of 16 g/m3(7.0 grain/ft3). The objective of this research is to demonstrate a significant reduction of financial cost in procuring electricity, assuming that PM2.5 and PM10 emission control improves with heavier loads and lower inlet velocities. Lowering the inlet velocity translates to reducing the energy use. Thus, it diminishes the electricity cost. The results proved that larger cyclones achieved efficiency with lower inlet velocity while the emissions control remained constant for both sized cyclones. Therefore, a cost-benefit analysis is proposed to demonstrate the financial advantages for operating larger cyclones over conventional ones. Cotton gins have a readily available supply of biomass that is a by-product of cotton ginning. A 40 bph-cotton gin processing stripped cotton must manage 2,600 to 20,000 tonnes of cotton gin trash (CGT) annually.
Suggested Alternatives:
The diameter of the oversized cyclones, used in the experiments, is approximately (√2 or 42%) times bigger than standard sized cyclones, 36 in and 50 in cyclones. Based on this difference among diameters, the changes in capital, electricity consumption savings and PM emissions will be observed at a square root of two (√2) as well.
Capital
In theory, capital investment only varies depending on the cyclone size. Based on standard diameter sizes used in commercial ginning, prices vary from $1,338.35 up to $4,225.20. Thus, an average of 83% of higher capital investment is expected when the price of a cyclone is compared to another √2 times bigger in diameter. Since the cotton ginning industry is already mature and its tendency is to replace to fewer but bigger cyclones, fitting adjustments to existent gin facilities have to be considered. Instead of calculating the installation of cyclones in brand new facilities, the recommendation is to expect adjustment costs to widely vary depending on the necessary modifications.
Diameter (in.) / Cost (US Dollars) / Price Variance (√2)36 / $1,338.35 / -
42 / $1,575.80 / -
50 / $2,233.30 / 67%
60 / $3,045.25 / 93%
72 / $4,225.20 / 89%
Average % / 83%
PM Emissions
In order to determine and compare the collection efficiency of a standard−sized 1D3D cyclone with the recommended inlet air velocity of 16.3 m/s (3200 ft./min), USDA ARS researchers used over−sized 1D3D and 2D2D cyclones with twice the inlet area (42% or √2 times larger diameter) and with an inlet velocity that was half of the recommended value. Whitelock Et. Al. suggests airflow rates of 10,000ft/m for 60 in. diameter cyclones and 14,500 ft./m for 72 in. diameter cyclones. If these cyclones run at half of the recommended inlet velocity, they should control PM emissions .20 % less efficiently than √2 smaller cyclones that are run at the suggested values.
Efficiency at .88 grain/ft. / 97.94%Efficiency at 1.75 grain/ft. / 98.44%
Efficiency at 3.5 grain/ft. / 98.64%
Efficiency at 7 grain/ft. / 98.96%
Electricity Consumption Savings
Maintenance expenditures are too low. Thus, electricity consumption is the main expense. The principal objective of this paper is to prove a feasible reduction in electric usage by operating larger cyclones. Based onpublished values from the cotton ginning industry; the average cost of electricity per bale, $3.79, reported for 2010 (Valco, et al., 2012) divided by the average kWh per bale, 34.5, (Funk & Hardin IV, 2013) results in an average electrical energy cost of $0.11 kWh-1.
Electricity costs overtime to increase
As inflation takes place, electricity rates are also expected to fluctuate. The NPV will be calculated for a period of twenty-five years, as of 2040. Unlike other long-term assets, cyclones are fully paid in front by the cooperative that runs the ginning plant. Therefore none discount rate is estimated. Based on the last report of the US Energy Information Administration, this has been the average retail price of electricity to commercial customers over the last ten years.
Year / 2004 / 2005 / 2006 / 2007 / 2008 / 2009 / 2010 / 2011 / 2012 / 2013 / 2014Price (Cents/KWh) / 8.17 / 8.67 / 9.46 / 9.65 / 10.26 / 10.16 / 10.19 / 10.24 / 10.09 / 10.29 / 10.44
Time Period / 2004-2005 / 2005-2006 / 2006-2007 / 2007-208 / 2008-2009 / 2009-2010 / 2010-2011 / 2011-2012 / 2012-2013 / 2013-2014
% Variance / 6.12 / 9.11 / 2.01 / 6.32 / -0.97 / 0.30 / 0.49 / -1.46 / 1.98 / 1.46
Time Period / 2004-2005 / 2005-2006 / 2006-2007 / 2007-208 / 2008-2009 / 2009-2010 / 2010-2011 / 2011-2012 / 2012-2013 / 2013-2014
Range Variance / 0.5 / 0.79 / 0.19 / 0.61 / -0.1 / 0.03 / 0.05 / -0.15 / 0.2 / 0.15
According to these calculations, commercial electricity rates should increase by 2.53% every ten years. This can be reinforced with forecasting data for the next twenty-five years provided by the Department of Energy
Year / Real Prices (2012 as base) / Nominal Prices2011 / $10.42 / $10.23
2012 / $10.08 / $10.08
2013 / $10.05 / $10.20
2014 / $10.11 / $10.44
2015 / $10.23 / $10.74
2016 / $10.28 / $10.96
2017 / $10.36 / $11.20
2018 / $10.48 / $11.51
2019 / $10.58 / $11.80
2020 / $10.51 / $11.90
2021 / $10.45 / $12.03
2022 / $10.34 / $12.10
2023 / $10.29 / $12.25
2024 / $10.41 / $12.60
2025 / $10.42 / $12.84
2026 / $10.45 / $13.10
2027 / $10.52 / $13.41
2028 / $10.55 / $13.68
2029 / $10.58 / $13.98
2030 / $10.67 / $14.36
2031 / $10.75 / $14.76
2032 / $10.76 / $15.07
2033 / $10.76 / $15.38
2034 / $10.83 / $15.79
2035 / $10.91 / $16.25
2036 / $11.00 / $16.74
2037 / $11.07 / $17.21
2038 / $11.10 / $17.62
2039 / $11.17 / $18.13
2040 / $11.26 / $18.67
Stakeholders
Ginning Management
Ginning facilities are usually owned by cooperatives. These set tariffs and fees based on the type of service to be provided. By reducing the amount of electricity consumed, the cost of ginning should decrease as well. Along with electric savings, the cost of new operational planning should be taken into consideration
References
Faulkner, W., & Shaw, B. (n.d.). Efficiency And Pressure Drop Of Cyclones Across A Range Of Inlet Velocities. Applied Engineering in Agriculture, 155-161.
Whitelock, D., Armijo, C., Buser, M., & Hughs, S. (n.d.). Using Cyclones Effectively at Cotton Gins. Applied Engineering in Agriculture, 563-576.
Baker, K., Funk, P., & Hughs, S. (n.d.). Over-Sized Cyclones For Low Pressure Cotton Gin Exhausts. Applied Engineering in Agriculture.
Saucier, D. S. (2013). Cyclone Performance for Reducing Biochar Concentrations in Syngas. College Station,TX.
Armijo, C., & Gillum, M. (n.d.). Conventional and High-Speed Roller Ginning of Upland Cotton in Commercial Gins. Applied Engineering in Agriculture, 5-10.