Research Article | | Peer-Reviewed

Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania

Received: 10 November 2023     Accepted: 1 December 2023     Published: 30 August 2024
Views:       Downloads:
Abstract

Tea processing is an energy-intensive process. However, high agricultural productivity and subsequently the growth of the green revolution have been made possible only by a large amount of energy inputs, especially those from fossil fuels, wood fuels, and electricity. With recent price rise and scarcity of these fuels there has been a trend towards use of alternative energy sources such as waste (agricultural waste) to energy that could solve both energy and environment issues. Moreover, these energy resources have not been able to provide an economically viable solution for agricultural applications so long as they seem to contain amount of energy which can be source of energy to be used in various factories in rural areas through gasification process. A gasifier is normally fuel specific system and it is tailored around a fuel rather than the other way round. Hence, this paper presents an experimental assessment of energy potentials from tea wastes available at Itonaa Tea Factory for tea drying processes as important data for agricultural wastes. The experimental measurement of energy potential from tea wastes was done using bomb calorimeter, muffle furnace and energy balances to determine calorific value moisture content and energy potentials of tea waste respectively. The findings indicate that the combined energy potential of factory and garden tea waste was found to be 2.78x108kWh, and corresponding electrical energy was estimated to be 2.78x107kWh which is enough for tea drying process in tea manufacturing plant. The total energy used in the production of tea was discovered to be equal 3.5 - 7.5 kWh/kg of made tea. Thus, total energy consumption (4.5 kWh/kg of made tea) for processing of 9.6 x 106 kg of tea from 4.5 x 103 hectares of tea plantation in Mufindi for the period of 2021-2022 was 4.32x107 kWh. Thus, with the proper utilization of energy conversion technology of tea waste, part of the energy requirement in processing of tea could be met reducing environmental challenges associated with both wood fuel burning and tea waste disposal.

Published in International Journal of Energy and Power Engineering (Volume 13, Issue 4)
DOI 10.11648/j.ijepe.20241304.11
Page(s) 63-66
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Factory Tea Waste, Potential Energy, Calorific Value, Garden Tea Waste

1. Introduction
Tea is undoubtedly the most popular beverage in the world , and due to its therapeutic benefits, including its anti-oxidative, anti-tumor, and anti-carcinogenic characteristics, it has gained more popularity recently . Both consumers and scientists have recognized and arouse interest in the numerous health benefits of tea as a result tea processing receives special attention because it has a direct impact on tea quality . The balanced flavor of made tea is achieved upon drying because moisture is eliminated thus inhibiting fermentation and extending tea’s storage life .
Tea processing includes a number of energy-intensive unit activities, including plucking, withering, rolling, maceration, fermentation, drying, grading, and packing . Processing tea is a higher energy process that uses a ratio of 15:85 of electrical and thermal energy . Thermal energy is extensively used during withering and drying processes, whereas electrical energy is used to power motors, fans, humidifiers, and lighting.
Itona tea factory is located at Itona Mufindi, Mafinga – Tanzania to which both forest and tea plantations are found at large. As per Tanzania Forest Agency (TFS) pine trees cover a big land as compared to other species of trees. Itona tea factories had to switch from oil furnaces to firewood-based boilers due to the rise in global oil prices and unstable, low – quality power supplied by TANESCO. The specific energy consumption varies from 4 -10.4 kWh/kg of made tea . This transition is fraught with challenges, including the loss of forest cover and large quantities of money spent on buying firewood. The consequences of climate change have been amplified by the loss of trees, which has had an impact on tea production, resulting in lower yield .
In order to produce tea in a sustainable manner, it is vital to pay close attention to energy consumption trends in the tea industry . As a result, a good use of tea waste could fulfill a portion of the energy necessary in tea processing. Tea waste includes both processing (factory) waste and garden waste. During the sorting or grading of manufactured tea, processing waste is generated. The fibers are removed from the primary tea during this process. Garden waste, on the other hand, is generated during the off-season when tea bushes are pruned. The tea waste from bush varies from 2-2.5 kg for wet matter basis per bush per year in a 4-year pruning cycle. According to a study the tea waste generation is about 2% of the total tea production . Therefore, utilizing tea waste in a productive way could provide some of the energy needed for the tea-processing process. Tea waste is a biomass in which energy can be generated through gasification and pyrolysis.
2. Methods and Materials
During the assessment, samples and amount of tea bush were collected from Itona Tea factory in Mfindi Tanzania. Both processing (factory) waste and garden waste were collected as samples for assessment of moisture content, calorific value and their total available energy as follows:
2.1. Determination of the Moisture Content (MC)
The samples were broken up into tiny pieces and kept at 105 °C for a full day in a muffle furnace. The moisture content of factory waste, garden waste leaves and branches were calculated by using Equation 1.
MC=Wws- WdsWwx100(1)
Where,
Wws = Weight of wet sample
Wds = Weight of dry sample
2.2. Calorific Value
A bomb calorimeter was used to measure the calorific value of the sample. A bomb-calorimeter measures the amount of heat produced when a sample is burned under controlled conditions in a closed vessel that is submerged in water and has an oxygen atmosphere. A calorimeter is used to measure the increase in temperature caused by the heat released into the surrounding water during the burning process, which is dictated by the burning process. The calorific value of the sample is determined using the formula as shown in Equation 2.
Calorific Value kWhkg=Ww x T1-T0Ws x C(2)
Where,
Ww = Weight of water equivalent to calorimeter (g)
T0 = Temperature before firing (°C)
T1 = Maximum temperature after firing (°C)
Ws = Weight of sample (g)
C = 0.00116 (Constant).
2.3. Energy Potential Estimation from Tea Waste
Energy balances was applied to calculate energy potentials of tea waste from two sources namely factory and garden source.
2.3.1. Factory tea waste (FTW)
The energy potential of factory tea waste was determined by Eq. 3,
Ep(kWh)=PKgx0.02Fcv(kWh/kg)(3)
Where,
Ep = Total energy (kWh)
P = Tea production (kg)
Fcv = Calorific value of tea waste from the factory (kWh/kg)
0.02 = Constant, percentage of tea waste generated
2.3.2. Garden Waste
The energy potential of tea bush waste and shade tree waste was calculated by using Eq. (4).
Ep(kWh)=BwKgxNxA(ha)Gcv(kWh/kg)(4)
Where,
Ep = Total energy (kWh)
Bw = Waste from tea bush (kg)
N = Total number of tea bush/hectare
A = Plantation area of the tea bush (ha)
Gcv = calorific value of the waste’s tea bush (kWh/kg)
3. Results and Discussions
This section presents findings and briefly explains its implications in the context of the study. The main objective of the study was to estimate the energy potentials of tea waste as a source of energy for Itona tea factory.
About 2% of the total tea produced was wasted during the sorting process. Withering (35%), crush tear curl (CTC) (6%), fermentation (0.7%), drying (57%), sorting (0.6%), packaging (0.1%), and auxiliary activities (0.6%) were shown to use the most energy among the many unit operations in the manufacture of tea. It was discovered that the overall energy used in the processing tea was between 3.5 and 7.5 kWh/kg of produced tea. The average pruned tea leaves and branches obtained were recorded as 10 kg/tea bush/pruning cycle. Thus, the average annual pruned material obtained in a pruning cycle of 4 year was 2.5 kg/tea bush. The average moisture content of processing (tea factory) waste, tea bush pruned leaves, tea bush pruned branches were determined as 2%, 80 %, 58 %, for wet basis, respectively.
3.1. Computation of Energy in Tea Waste
Using a bomb calorimeter, the calorific value of tea waste samples was determined, and it was found that the average calorific value of processed tea waste was 5.056 kWh/kg. As demonstrated in Table 1, the average calorific value of the garden waste samples (tea leaves and branches) that were gathered and examined was determined to be 4.303 kWh/kg.
Table 1. Calorific value of tea bush waste.

Garden waste

Calorific value (kWh/kg)

Average calorific value(kWh/kg)

Tea leaves

4.282

4.303

Branch of tea bush

4.324

3.2. Energy Potential of Tea Waste
The energy potential from processing tea waste (approximately 1.91 x 105 kg) in Itona tea factory during the year 2021-2022 was calculated as 1.062 x 106 kWh as represented in Table 2. On the other hand, the energy obtainable from the garden tea bush pruned materials (leaves and branches) was estimated as 3.25 x 108 kWh as shown in Table 3.
Table 2. Energy potential of factory tea waste.

Parameters

Value

Annual tea production around Itona (kg)

9.550531 x 106

Tea waste (kg)

1.91 x 105

Calorific value (kWh/kg)

5.056

Energy potential (kWh)

1.062 x 106

Table 3. Energy potential of garden tea bush wate.

Parameters

Value

Tea plantation area around Itona tea factory (hectare)

4500

Spacing between rows (m)

1.05

Spacing between bushes (m)

0.70

Bush/area (m2)

1.05 x 0.70 = 0.735

Bush/area (hectare)

10000/0.735 = 13605

Total number of bushes

13605 x 4500 = 6.12 x 107

Garden tea waste/bush/year (wet matter basis) (kg)

2.5

Garden tea waste/bush/ per year (dry matter basis) (kg)

1.05

Total garden tea waste (dry matter basis) (kg)

6.12 x 107 x 1.05 = 6.43 x 107

3.3. Energy Consumption in Tea Factory
The total energy consumption in tea manufacturing was found to be 3.5 - 7.5 kWh/kg of made tea. Hence, the total energy consumption (4.5 kWh/kg of made tea) for processing 9.6 x 106 kg of tea from 4500 hectares tea plantation in Mfindi district during the year 2021 - 2022 was 4.32x107 kWh from which the thermal energy consumption per kg of tea produced was around 5.67 times that of electrical energy as compared to data by Mwenda, (2016).
3.4. Energy Saving Using Tea Waste
Mufindi District tea estate waste produced 2.78x108kWh of usable energy. Energy conversion efficiency of calorific value to electrical energy was assumed to be 10%. The total amount of energy in terms of electrical energy that can be obtained from wastes in tea estates was estimated to be 2.78 x 107 kWh. Hence, the total energy available from tea waste compared with total energy consumption annually during manufacturing of tea (4.32x107 kWh, 4.5 kWh/kg of made tea) shows that 64.4% amount of energy required in tea processing could be saved with the utilization such as gasification technology of tea waste generated from tea industries.
4. Conclusion
The total energy potential of tea waste (factory and garden waste) was estimated as 2.78x108kWh. Thus, with the positive utilization of tea waste, part of the energy requirement in processing of tea could be met. It could replace the use of wood fuel for tea drying and therefore minimizing environmental challenges associated with both wood fuel burning and tea waste disposal.
Conflicts of Interest
The authors declare no conflicts of interest.
References
[1] W. C. Reygaert, “Green Tea Catechins: Their Use in Treating and Preventing Infectious Diseases,” vol. 2018, 2018.
[2] B. Debnath, D. Haldar, and M. K. Purkait, “Potential and sustainable utilization of tea waste: A review on present status and future trends,” J. Environ. Chem. Eng., vol. 9, no. 5, p. 106179, 2021,
[3] H. Vishnoi, R. Bodla, R. Kant, and R. B. Bodla, “Green Tea (Camellia Sinensis) and Its Antioxidant Property: a Review,” Artic. Int. J. Pharm. Sci. Res., vol. 9, no. 5, p. 1723, 2018,
[4] J. L. Taulo and A. B. Sebitosi, “Material and energy flow analysis of the Malawian tea industry,” Renew. Sustain. Energy Rev., vol. 56, pp. 1337–1350, 2016,
[5] T. R. Dias, G. Tomás, N. F. Teixeira, M. G. Alves, P. F. Oliveira, and B. M. Silva, “White Tea (Camellia Sinensis (L.)): Antioxidant Properties And Beneficial Health Effects,” Int. J. Food Sci. Nutr. Diet., vol. 2, no. 2, pp. 19–26, 2013.
[6] M. Saeed et al., “Green tea (Camellia sinensis) and L-theanine: Medicinal values and beneficial applications in humans—A comprehensive review,” Biomed. Pharmacother., vol. 95, no. July, pp. 1260–1275, 2017,
[7] J. Xia, Z. Guo, S. Fang, J. Gu, and X. Liang, “Effect of Drying Methods on Volatile Compounds of Burdock,” Foods, vol. 70, no. 868, pp. 1–17, 2021.
[8] K. Teshome, “Effect of tea processing methods on biochemical composition and sensory quality of black tea (Camellia sinensis (L.) O. Kuntze): A review,” J. Hortic. For., vol. 11, no. 6, pp. 84–95, 2019,
[9] K. R. J. Pou, S. K. Paul, and S. Malakar, Industrial processing of CTC black tea. Elsevier Inc., 2019.
[10] J. I. Mwenda, “Analysis of energy utilization and renewable energy potential in KTDA region two tea factories in Kenya kenyatta university,” Master Sci. Degree Energy Technol., 2016.
[11] P. P. Dutta and D. C. Baruah, “Gasification of tea (Camellia sinensis (L.) O. Kuntze) shrubs for black tea manufacturing process heat generation in Assam, India,” Biomass and Bioenergy, vol. 66, pp. 27–38, 2014,
[12] C. R. Muoki, T. K. Maritim, W. A. Oluoch, S. M. Kamunya, and J. K. Bore, “Combating Climate Change in the Kenyan Tea Industry,” Front. Plant Sci., vol. 11, no. March, pp. 1–10, 2020,
[13] S. L. Jayasinghe and L. Kumar, “Potential impact of the current and future climate on the yield, quality, and climate suitability for tea [camellia sinensis (L.) O. Kuntze]: A systematic review,” Agronomy, vol. 11, no. 4, 2021,
[14] R. Gupta and S. K. Dey, “Development of a productivity measurement model for tea industry,” J. Eng. Appl. Sci., vol. 5, no. 12, pp. 16–25, 2010.
[15] A. Chowdhury, S. Sarkar, A. Chowdhury, S. Bardhan, P. Mandal, and M. Chowdhury, “Tea waste management: A case study from West Bengal, India,” Indian J. Sci. Technol., vol. 9, no. 42, 2016,
Cite This Article
  • APA Style

    Mwampulo, A. S., Omari, A. M., Mwakipesile, D. (2024). Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania. International Journal of Energy and Power Engineering, 13(4), 63-66. https://doi.org/10.11648/j.ijepe.20241304.11

    Copy | Download

    ACS Style

    Mwampulo, A. S.; Omari, A. M.; Mwakipesile, D. Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania. Int. J. Energy Power Eng. 2024, 13(4), 63-66. doi: 10.11648/j.ijepe.20241304.11

    Copy | Download

    AMA Style

    Mwampulo AS, Omari AM, Mwakipesile D. Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania. Int J Energy Power Eng. 2024;13(4):63-66. doi: 10.11648/j.ijepe.20241304.11

    Copy | Download

  • @article{10.11648/j.ijepe.20241304.11,
      author = {Andrew Stephen Mwampulo and Arthur Mngoma Omari and Duncan Mwakipesile},
      title = {Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania
    },
      journal = {International Journal of Energy and Power Engineering},
      volume = {13},
      number = {4},
      pages = {63-66},
      doi = {10.11648/j.ijepe.20241304.11},
      url = {https://doi.org/10.11648/j.ijepe.20241304.11},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijepe.20241304.11},
      abstract = {Tea processing is an energy-intensive process. However, high agricultural productivity and subsequently the growth of the green revolution have been made possible only by a large amount of energy inputs, especially those from fossil fuels, wood fuels, and electricity. With recent price rise and scarcity of these fuels there has been a trend towards use of alternative energy sources such as waste (agricultural waste) to energy that could solve both energy and environment issues. Moreover, these energy resources have not been able to provide an economically viable solution for agricultural applications so long as they seem to contain amount of energy which can be source of energy to be used in various factories in rural areas through gasification process. A gasifier is normally fuel specific system and it is tailored around a fuel rather than the other way round. Hence, this paper presents an experimental assessment of energy potentials from tea wastes available at Itonaa Tea Factory for tea drying processes as important data for agricultural wastes. The experimental measurement of energy potential from tea wastes was done using bomb calorimeter, muffle furnace and energy balances to determine calorific value moisture content and energy potentials of tea waste respectively. The findings indicate that the combined energy potential of factory and garden tea waste was found to be 2.78x108kWh, and corresponding electrical energy was estimated to be 2.78x107kWh which is enough for tea drying process in tea manufacturing plant. The total energy used in the production of tea was discovered to be equal 3.5 - 7.5 kWh/kg of made tea. Thus, total energy consumption (4.5 kWh/kg of made tea) for processing of 9.6 x 106 kg of tea from 4.5 x 103 hectares of tea plantation in Mufindi for the period of 2021-2022 was 4.32x107 kWh. Thus, with the proper utilization of energy conversion technology of tea waste, part of the energy requirement in processing of tea could be met reducing environmental challenges associated with both wood fuel burning and tea waste disposal.
    },
     year = {2024}
    }
    

    Copy | Download

  • TY  - JOUR
    T1  - Experimental Assessment of Energy Potentials from Tea Wastes as a Source of Energy: A Case of Itona Tea Factory in Tanzania
    
    AU  - Andrew Stephen Mwampulo
    AU  - Arthur Mngoma Omari
    AU  - Duncan Mwakipesile
    Y1  - 2024/08/30
    PY  - 2024
    N1  - https://doi.org/10.11648/j.ijepe.20241304.11
    DO  - 10.11648/j.ijepe.20241304.11
    T2  - International Journal of Energy and Power Engineering
    JF  - International Journal of Energy and Power Engineering
    JO  - International Journal of Energy and Power Engineering
    SP  - 63
    EP  - 66
    PB  - Science Publishing Group
    SN  - 2326-960X
    UR  - https://doi.org/10.11648/j.ijepe.20241304.11
    AB  - Tea processing is an energy-intensive process. However, high agricultural productivity and subsequently the growth of the green revolution have been made possible only by a large amount of energy inputs, especially those from fossil fuels, wood fuels, and electricity. With recent price rise and scarcity of these fuels there has been a trend towards use of alternative energy sources such as waste (agricultural waste) to energy that could solve both energy and environment issues. Moreover, these energy resources have not been able to provide an economically viable solution for agricultural applications so long as they seem to contain amount of energy which can be source of energy to be used in various factories in rural areas through gasification process. A gasifier is normally fuel specific system and it is tailored around a fuel rather than the other way round. Hence, this paper presents an experimental assessment of energy potentials from tea wastes available at Itonaa Tea Factory for tea drying processes as important data for agricultural wastes. The experimental measurement of energy potential from tea wastes was done using bomb calorimeter, muffle furnace and energy balances to determine calorific value moisture content and energy potentials of tea waste respectively. The findings indicate that the combined energy potential of factory and garden tea waste was found to be 2.78x108kWh, and corresponding electrical energy was estimated to be 2.78x107kWh which is enough for tea drying process in tea manufacturing plant. The total energy used in the production of tea was discovered to be equal 3.5 - 7.5 kWh/kg of made tea. Thus, total energy consumption (4.5 kWh/kg of made tea) for processing of 9.6 x 106 kg of tea from 4.5 x 103 hectares of tea plantation in Mufindi for the period of 2021-2022 was 4.32x107 kWh. Thus, with the proper utilization of energy conversion technology of tea waste, part of the energy requirement in processing of tea could be met reducing environmental challenges associated with both wood fuel burning and tea waste disposal.
    
    VL  - 13
    IS  - 4
    ER  - 

    Copy | Download

Author Information
  • Department of Electrical and Power Engineering, Mbeya University of Science and Technology, Mbeya, Tanzania

  • Department of Electrical and Power Engineering, Mbeya University of Science and Technology, Mbeya, Tanzania

  • Department Mechanical and Industrial Engineering, Mbeya University of Science and Technology, Mbeya, Tanzania

  • Abstract
  • Keywords
  • Document Sections

    1. 1. Introduction
    2. 2. Methods and Materials
    3. 3. Results and Discussions
    4. 4. Conclusion
    Show Full Outline
  • Conflicts of Interest
  • References
  • Cite This Article
  • Author Information