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Clean Technologies and Environmental Policy

, Volume 21, Issue 1, pp 139–153 | Cite as

An integrated strategy targeting drying and cooling unit operations to improve economic viability and reduce environmental impacts in a mango processing plant

  • Aaron Dzigbor
  • Annie ChimphangoEmail author
Original Paper
  • 57 Downloads

Abstract

An integrated strategy of replacing boiler fuel and vapour compression cooling technology in dried mango chips processing plant powered on-grid and off-grid was investigated. Three scenarios for each power setting were studied: on-grid: coal as boiler fuel and conventional vapour compression chiller (CVCC) for cooling (scenario 1), mango seed as boiler fuel and CVCC for cooling (scenario 2) and mango seed as boiler fuel and adsorption cooling system (ACS) for cooling (scenario 3). Off-grid scenarios 4, 5 and 6 corresponded to on-grid scenarios 1, 2 and 3, respectively. Greenhouse gas (GHG) emissions and economic viability for each scenario were based on material and energy balances and South African economic conditions, respectively. On-grid scenario 3 showed the greatest potential for reducing emissions, emitting 7.10 × 105 kg CO2eq per annum and had best internal rate of return (IRR) of 25.33% compared to scenarios 2 and 1 with 7.21 × 105 kg CO2eq and 7.89 × 105 kg CO2eq emissions per annum and IRR of 20.33% and 17.48%, respectively. In off-grid, scenario 6 emitted the least GHG of 6.90 × 105 kg CO2eq and had the highest IRR of 24.84% compared to scenarios 5 and 4 with 6.98 × 105 kg CO2eq and 7.67 × 105 kg CO2eq emissions per annum and IRR of 18.88% and 16.09%, respectively. However, scenarios 3 and 6 had the highest energy demand due to mango seed drying. Nevertheless, the integrated intervention shows a great potential of reducing environmental impacts and improving the economic viability of a dried mango chips processing plant by using renewable biomass fuel and ACS that utilizes boiler waste heat. Mango seed can be solar dried to reduce increased energy demand.

Graphical abstract

Keywords

Adsorption chiller Vapour compression cooler/chiller Environmental impact Mango seed Economic impact 

List of symbols

TS

Total solid

TCI

Total capital investment

CVCC

Conventional vapour compression cooler/chiller

LCAC

Low-cost adsorption chiller/cooler

ACS

Adsorption chiller

\(C\)

Equipment cost at the current year

\(C_{\text{O}}\)

Equipment cost at some time in the past

CEPCI

Chemical engineering plant cost index

\(C_{{p,{\text{solid}}}}\)

Specific heat of dried product (J/kg °C)

\(C_{{p,{\text{water}}}}\)

Specific heat of water (J/kg °C)

GWP

Global warming potential

IRR

Internal rate of return

\(m_{\text{fuel}}\)

Amount of diesel fuel used by the truck (kg)

\(M\)

Scaled-up equipment capacity

\(M_{\text{O}}\)

Original equipment capacity

\(m_{\text{solid}}\)

Mass of final dried product (kg)

\(m_{\text{water}}\)

Mass of water evaporated product (kg)

NPV

Net present value

\(P_{\text{elect}}\)

Electrical power requirement of the equipment (kW)

\(Q_{\text{useful}}\)

Useful fraction of the fuel energy used in the process (J)

\(Q_{\text{elect}}\)

Electrical heat generated (J)

\(Q_{\text{dryer}}\)

Total energy required for drying (J)

\(Q_{\text{solid}}\)

Energy required to raise the temperature of mango chips from room temperature to the final product drying temperature (J)

\(Q_{\text{sensible}}\)

Energy required to raise temperature of water in the mango chips to 100 °C (J)

\(Q_{\text{latent}}\)

Latent heat of vaporization of water (J)

\(Q_{\text{fuel}}\)

Heating value of the diesel (MJ/kg)

\(Q_{\text{trans}}\)

Transportation energy consumed (MJ)

\(M_{\text{compost}}\)

Mass of waste to be composted

\(t\)

Working duration (h)

\(T_{\text{f}}\)

Final product drying temperature (°C)

\(T_{\text{i}}\)

Initial drying temperature (°C)

\(\eta_{\text{th}}\)

Combustion efficiency

\(\lambda_{100}\)

Enthalpy of vaporization of water at 100 °C (J/kg)

\(\eta\)

Truck engine efficiency

n

Scaling index

Notes

Acknowledgements

Authors are grateful for the financial support by the National Research Foundation (NRF) of South Africa under the Research and Technology Fund (RTF) and the Department of Process Engineering, Stellenbosch University. The authors are also thankful to Hoedspruit Fruit Processors (South Africa) for providing the technical information needed for this study.

Supplementary material

10098_2018_1623_MOESM1_ESM.docx (66 kb)
Supplementary material 1 (DOCX 66 kb)

References

  1. Amer O, Boukhanouf R, Ibrahim HG (2015) A review of evaporative cooling technologies. Int J of Environ Sci Dev 6:111–117.  https://doi.org/10.7763/ijesd.2015.v6.571 CrossRefGoogle Scholar
  2. Askalany AA, Salem M, Ismail IM, Ali AHH, Morsy MG (2012) A review on adsorption cooling systems with adsorbent carbon. Renew Sustain Energy Rev 16:493–500.  https://doi.org/10.1016/j.rser.2011.08.013 CrossRefGoogle Scholar
  3. Askalany AA, Salem M, Ismail IM, Ali AHH, Morsy MG, Saha BB (2013) An overview on adsorption pairs for cooling. Renew Sustain Energy Rev 19:565–572.  https://doi.org/10.1016/j.rser.2012.11.037 CrossRefGoogle Scholar
  4. Bai J, Yang C, Zhao Z, Zhing X, Zhang Y, Xu J, Xi B, Liu H (2013) Effect of bulk density of coking coal on swelling pressure. J Environ Sci (China) 25:205–209.  https://doi.org/10.1016/S1001-0742(14)60657-4 CrossRefGoogle Scholar
  5. Barma MC, Saidur R, Rahman SMA, Allouhi A, Akash BA, Sait SM (2017) A review on boilers energy use, energy savings, and emissions reductions. Renew Sustain Energy Rev 79:970–983.  https://doi.org/10.1016/j.rser.2017.05.187 CrossRefGoogle Scholar
  6. Chang K, Vaagt G, Domingo S (2013) Mango-its current world market situation. http://www.cedaf.org.do/eventos/xmango2013/programa/001_FAO.pdf. Accessed 26 July 2015
  7. Cherubini F, Peters GP, Berntsen T, Stromman AH, Hertwich E (2011) CO2 emissions from biomass combustion for bioenergy: atmospheric decay and contribution to global warming. GCB Bioenergy 3:413–426.  https://doi.org/10.1111/j.1757-1707.2011.01102.x CrossRefGoogle Scholar
  8. CoCT (2017) Tarriff structure from 1 July 2017. https://resource.capetown.gov.za/cityassets/Files/Tariff_increases_from1July17.pdfAccessed 23 Nov 2017
  9. De la Cruz J, García H (2002) Mango: post-harvest operations. http://www.fao.org/fileadmin/user_upload/inpho/docs/Post_Harvest_Compendium_-_Mango.pdf. Accessed 10 Mar 2015
  10. Divekar SP, Bisen RD (2016) Engineering Properties of Locally Available Mango Stone. Int J Appl Pure Sci Agric 415712:121–130Google Scholar
  11. EIA (2011) Annual energy outlook with projections to 2035. https://www.eia.gov/outlooks/aeo/pdf/0383(2011).pdf. Accessed 31 May 2018
  12. EPA (2008) Direct emissions from mobile combustion sources. Energy Econ 34:1580–1588Google Scholar
  13. Evans A, Strezov V, Evans TJ (2009) Assessment of sustainability indicators for renewable energy technologies. Renew Sustain Energy Rev 13:1082–1088CrossRefGoogle Scholar
  14. FAO (2008) Climate change and food security. Food and Agricultural Organization of the United Nations. http://rstb.royalsocietypublishing.org/content/360/1463/2139.short. Accessed 23 July 2015
  15. Fernades MS, Brites GJVN, Costa JJ, Gaspar AR, Costa VAF (2014) Review and future trends of solar adsorption refrigeration systems. Renew Sustain Energy Rev 39:102–123.  https://doi.org/10.1016/j.rser.2014.07.081 CrossRefGoogle Scholar
  16. Garg A, Kazunari K, Pulles T (2006) 2006 IPCC guidelines for national greenhouse gas inventories, Volume 2: energy. http://www.ipcc-nggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_2_Ch2_Stationary_Combustion.pdf. Accessed 15 May 2016
  17. Gezae DA, Görgens JF (2017) Techno-economic analysis and environmental impact assessment of lignocellulosic lactic acid production. Chem Eng Sci 162:53–65.  https://doi.org/10.1016/j.ces.2016.12.054 CrossRefGoogle Scholar
  18. Gómez DR, Watterson JD, Americanohia BB, Ha C, Marland G, Matsika E, Namayanga LN, Osman-Elsha B (2006) IPCC guidelines for national greenhouse gas inventories. chapter 2: stationary combustion, http://www.ipccnggip.iges.or.jp/public/2006gl/pdf/2_Volume2/V2_2_Ch2_StationaryCombustion.pdf. Accessed 15 Nov 2017
  19. Ikegwu OJ, Ekwu FC (2009) Thermal and physical properties of some tropical fruits and their juices in Nigeria. J Food Technol 7:38–42Google Scholar
  20. Johnston WA, Nicholson FJ, Roger A, Stroud GD (1994) Freezing and refrigerated storage in fisheries. http://www.fao.org/3/a v3630e/V3630E00.htm#Contents. Accessed 16 Nov 2017
  21. Kittiphoom S (2012) Utilization of Mango seed. Int Food Res J 19:1325–1335Google Scholar
  22. Matheson Gas Products (2001) Gas Data Book 7th Edition. https://www.mathesongas.com/pdfs/products/Lower-(LEL)-&-Upper-(UEL)-Explosive-Limits-.pdf. Accessed 12 Sept 2018
  23. Mendu V, Shearin T, Campbell JE, Stork J, Jae J, Crocker M, Huber G, DeBolt S (2012) Global bioenergy potential from high-lignin agricultural residue. Proc Natl Acad Sci 109:4014–4019.  https://doi.org/10.1073/pnas.1112757109 CrossRefGoogle Scholar
  24. Peters MS, Timmerahus KD (1991) Plant design and economics for chemical engineers, 4th edn. McGraw Hill Inc, New YorkGoogle Scholar
  25. Rafferty K (2000) Geothermal Power Generation. Geo-Heat Center, pp.1–12. https://geoheat.oit.edu/pdf/powergen.pdf. Accessed 9 June 2015
  26. Research Markets and Economic Centre (2016) South African fruit trade flow. https://www.namc.co.za/wp-content/uploads/2018.03/South-African-Fuit-flow-report-Mar-2018-Issue-29.pdf. Accessed 2 Apr 2018
  27. Research Triangle Institute (RTI) (2010) Greenhouse gas emissions estimation methodologies for biogenic emissions from selected source categories : solid waste disposal wastewater treatment ethanol fermentation. https://www3.epa.gov/ttnchie1/efpac/ghg/GHG_Biogenic_Report_draft_Dec1410.pdf. Accessed 21 May 2018
  28. Riva G (2011) Utilization of renewable energy sources and energy-saving technologies by small-scale milk plants and collection centres. http://www.fao.org/docrep/004/T0515E/T0515E02.htm#ch2. Accessed 23 July 2015
  29. Suntivarakorn R, Treedet W (2016) Improvement of boiler’s efficiency using heat recovery and automatic combustion control system. Energy Procedia 100:193–197.  https://doi.org/10.1016/j.egypro.2016.10.164 CrossRefGoogle Scholar
  30. Ubabuike H, Alfred E (2012) Design and adaptation of a commercial cold storage room for umudike community and environs. IOSR J Eng 2:1234–1250CrossRefGoogle Scholar
  31. Wang SG, Wang RZ (2005) Recent developments of refrigeration technology in fishing vessels. Renew Energ 30:589–600CrossRefGoogle Scholar
  32. www.indexmundi.com [retrieved on 15 Jan 2018]
  33. Zacharias MB, George SD (2003) Food process design. Marcel Dekker Inc, New YorkGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Process EngineeringUniversity of StellenboschMatielandSouth Africa

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