Renewable Energy in Agriculture in Egypt
Technological Fundamentals of
Briquetting Cotton Stalks as a Biofuel

Dissertation

zur Erlangung des akademischen Grades
doctor rerum agriculturarum
(Dr. rer. agr.)

eingereicht an der
Landwirtschaftlich-Gärtnerischen Fakultät
der Humboldt-Universität zu Berlin

von
M.Sc. Ehab El Saeidy
Geboren am 10.08.1967 in El Menoufiya, Ägypten

Präsident der Humboldt-Universität zu Berlin
Prof. Dr. Jürgen Mlynek

Dekan: Dekan der Landwirtschaftlich-Gärtnerischen Fakultät
Prof. Dr. Uwe Jens Nagel

Gutachter:
1. Prof. Dr. Jürgen Hahn
2. Prof. Dr.-Ing. Klaus Nendel
3. Dr.-Ing. Volkhard Scholz

Tag der mündlichen Prüfung : 09.07 2004

Table of contents

• 1 Problem and objective
• 2 Review of literature
  • 2.1  Definitions, benefits and problems
    • 2.1.1  Biomass
    • 2.1.2 Solid crop residues
    • 2.1.3 Cotton stalks
  • 2.2 Phytosanitary issues concerning the use of cotton stalks
    • 2.2.1  Pink bollworm
    • 2.2.2 Damage by the pink bollworm
    • 2.2.3 Extermination of the cotton bollworm
  • 2.3 Technologies of cotton stalk processing
    • 2.3.1  Traditional lines in Egypt
    • 2.3.2 Present lines in other countries
  • 2.4 Briquetting
    • 2.4.1  Principles and technologies
    • 2.4.2 Calculation models
• 3 Potential of energetically usable farm residues in Egypt
  • 3.1  Quantity of energetically usable farm residues
  • 3.2 Quality of energetically usable farm residues
• 4 Energy consumption in Egypt
  • 4.1  National energy consumption
  • 4.2 Energy consumption in rural areas
• 5 Materials and methods
  • 5.1  Experimental programme
  • 5.2  Materials
    • 5.2.1  Poplar
    • 5.2.2 Hemp
    • 5.2.3 Straw
    • 5.2.4 Cotton stalks
  • 5.3 Processing
    • 5.3.1  Chopping
    • 5.3.2 Moisture adjustment
  • 5.4 Press experiments
  • 5.5 Briquette measurements
    • 5.5.1  Briquette density (ρ)
    • 5.5.2 Radial compressive strength (p_R )
    • 5.5.3 Briquette durability
  • 5.6  Temperature measurements and experiments
  • 5.7 Combustion experiments
• 6 Experimental results
  • 6.1  Laboratory press results
    • 6.1.1  Poplar
    • 6.1.2 Hemp
    • 6.1.3 Straw
    • 6.1.4 Cotton stalks
  • 6.2 Commercial press results
  • 6.3 Correlation of stability and density of briquettes
  • 6.4 Briquette durability
  • 6.5 Moisture content of cotton stalks on the field
  • 6.6 Temperature behaviour of cotton bollworms
  • 6.7 Temperature behaviour of briquettes
  • 6.8 Emissions of briquettes during combustion
• 7 Discussion of the experimental results
  • 7.1  Influence of material on density and stability of briquettes
  • 7.2 Influence of pressure on density and stability of briquettes
  • 7.3 Influence of moisture on density and stability of briquettes
  • 7.4 Influence of particle size on density and stability of briquettes
  • 7.5 Influence of press diameter on density and stability of briquettes
  • 7.6 Comparison of experimental results with the theoretical model
• 8 Socio-economic assessments of briquetting cotton stalks
  • 8.1  Introduction
  • 8.2 Production lines
    • 8.2.1  Stalk burning line
      • 8.2.1-1 Collection of the stalks
      • 8.2.1-2 Burning of the stalks
    • 8.2.2 Stalk storing line
      • 8.2.2-1 Collection of the stalks
      • 8.2.2-2 Transporting of the stalks
      • 8.2.2-3 Storing of stalks
    • 8.2.3 Stalk chopping line
      • 8.2.3-1 Collection of the stalks
      • 8.2.3-2 Transporting of the stalks
      • 8.2.3-3 Storing of the stalks
      • 8.2.3-4 Chopping the stalks
    • 8.2.4 Stalk briquetting line
      • 8.2.4-1 Collection of the stalks
      • 8.2.4-2 Transporting of the stalks
      • 8.2.4-3 Storing of the stalks
      • 8.2.4-4 Chopping the stalks
      • 8.2.4-5 Briquetting
  • 8.3 Costs
    • 8.3.1  Stalk burning line
    • 8.3.2 Stalk storing line
    • 8.3.3 Stalk chopping line
    • 8.3.4 Stalk briquetting line
  • 8.4 Discussion of costs
• 9  Conclusions
• References
• Acknowledgements
• Units
• Summary
• Appendix
• Eidesstattliche Erklärung

Tables

• Table 2.1: The technical features of briquetting and pellet machines
• Table 2.2: The coefficients used by Busse for grass at a moisture content of 15% (1966)
• Table 3.1: Heating value and compositional data for solid biofules
• Table 5.1: Experimental program Press: Lab press with ∅ 42.5 mm, length 400 mm, max. force 10000 kp Measuring parameters: moisture, bulk density, briquette length, briquette density, radial pressure stability
• Table 5.2: Experimental briquetting programme - ∅ 30 mm Press: Lab press with ∅ 30 mm, length 400 mm, max. force 10000 kp Measuring parameters: moisture, bulk density, briquette length, briquette density, radial pressure stability
• Table 5.3: Heating values and compositions of the experimental materials
• Table 5.4: Physical properties of the materials used for combustion
• Table 6.1: Physical properties of the experimental raw materials
• Table 6.2: Results of the commercial press compared to the results of the laboratory press
• Table 6.4: The results of the combustion experiments
• Table 6.5: Chemical analyses of the experimental materials
• Table 7.1: Density and stability of briquettes depending on pressure and moisture content for various medium chopped materials and a stamp diameter of 30 mm
• Table 8.1: Burning line (1)
• Table 8.2: Stalks storing line (2)
• Table 8.3: Chopping line (3)
• Table 8.4: Briquetting line (4)

Images

• Fig. 2.1: Larvae of the pink bollworm
• Fig. 2.2: Life cycle of pink bollworm (Ellsworth, et al., 2003)
• Fig. 2.3: Seasonal Life cycle of pink bollworm (Ellsworth, et al, 2003)
• Fig. 2.4: Damage caused by the cotton bollworm (Integrated pest management project, University of California, 2002)
• Fig. 2.5: Combustion of cotton stalks in a traditional oven in Egypt
• Fig. 2.6: Cotton stalks burning on the fields
• Fig. 2.7: Operating principles of typical briquette and pellet machines (FAO, 1990; FNR, 2000).
• Fig. 2.8: The principle of the high pressure piston press (Clauß, 2002)
• Fig. 3.1: The average yield of the main crops and their residues in Egypt (MALR, 2002)
• Fig. 3.2: The energetically usable and used main crop residues in Egypt (MALR, 2002)
• Fig. 4.1: Primary energy resources and production in Egypt (OECP, 2002)
• Fig. 4.2: The consumption of primary energy in Egypt (OECP, 2002)
• Fig. 4.3: Sectoral consumption of primary energy in Egypt (OECP, 2002)
• Fig. 4.4: Development of CO₂ emissions in Egypt (OECP, 1998)
• Fig. 5.1: The experimental materials (raw)
• Fig. 5.2: The experimental materials (chopped)
• Fig. 5.3: A cross section of hemp stalks (Mehlich, J. 1998; Drieling, 1999).
• Fig. 5.4: Cumulative frequency distribution of poplar chips
• Fig. 5.5: Cumulative frequency distribution of hemp shives
• Fig. 5.6: Cumulative frequency distribution of rye straw
• Fig. 5.7: Cumulative frequency distribution of cotton stalks
• Fig. 5.8: The laboratory chopper
• Fig. 5.9: The hammer mill
• Fig. 5.10: Increasing the moisture content after total drying of experimental materials
• Fig. 5.11: Construction of the press instruments of the press machine
• Fig. 5.12:Lab press machine (WMF, Leipzig)
• Fig. 5.13: Operating principle of the commercial press machine (SP 45/12)
• Fig. 5.14: Test machine for measuring the radial compressive strength of briquettes
• Fig. 5.15: The breaking path of cotton stalk briquettes
• Fig. 5.16: Test machine for briquette durability
• Fig. 5.17 : Combustion test stand of ATB
• Fig. 6.1: Density of briquette versus pressure for medium-sized chopped poplar (∅ 45.5 mm)
• Fig. 6.2: Density of briquette versus pressure for chopped poplar (∅ 30 mm)
• Fig. 6.3: Density of briquette versus pressure for medium chopped hemp (∅ 45.5 mm)
• Fig. 6.4: Density of briquette versus pressure for chopped hemp (∅ 30 mm)
• Fig. 6.5: Density of briquette versus pressure for medium chopped rye straw (∅ 45.5 mm)
• Fig. 6.6: Density of briquette versus pressure for chopped rye straw (∅ 30 mm)
• Fig. 6.7: Density of briquette versus pressure for middle chopped cotton stalks (∅ 42.5 mm)
• Fig. 6.8: Density of briquette versus pressure for chopped cotton stalks (∅ 30 mm)
• Fig. 6.9: Relation between radial stability and density of briquette from medium chopped hemp (∅ 42.5 mm)
• Fig. 6.10: Relation between radial stability and density of middle chopped materials (∅ 30 mm)
• Fig. 6.11: Influence of the press diameter on briquette stability depending on density of briquette of medium chopped hemp
• Fig. 6.12: The moisture content of cotton stalks and relevant climate parameters on the field in Egypt
• Fig. 6.13: The effect of temperature and time on the survival rate of cotton pink bollworms
• Fig. 6.14: Development of the internal temperature of hemp briquettes depending on the operation time of the commercial press (SP 45/12)
• Fig. 6.15: Dry matter loss of the experimental materials after one hour depending on temperature
• Fig. 6.16: The increase of the internal temperature of briquettes depending on time for various outside temperatures
• Fig. 6.17: Course of emissions during combustion of poplar branches
• Fig. 6.18: Course of emissions during combustion of poplar briquettes
• Fig. 6.19: Course of emissions during combustion of hemp shives
• Fig. 6.20: Course of emissions during combustion of hemp briquettes
• Fig. 6.21: Course of emissions during combustion of straw stalks
• Fig. 6.22: Course of emissions during combustion of straw briquettes
• Fig. 7.1: Influence of the pressure on density of medium chopped materials
• Fig. 7.2: Influence of the pressure on briquette stability
• Fig. 7.3: Density of briquette versus moisture content
• Fig. 7.4: Density of briquette versus moisture content for medium chopped materials
• Fig. 7.5: Influence of particle size and stamp diameter on briquette density
• Fig. 7.6: Influence of the press diameter on briquette density of middle chopped materials
• Fig. 7.7: Influence of the press diameter on briquette stability of middle chopped hemp
• Fig. 7.8: Comparison of experimental and theoretical results for poplar, hemp and straw (10% moisture content)
• Fig. 8.1: Production lines for the energetic use of cotton stalks
• Fig. 8.2: Costs of each process step of the production lines analysed
• Fig. 8.3: The costs of various production lines for the utilization of cotton stalks in Egypt