Part 1: Capacity Planning and Technical Basis
1. Plant Capacity
and Expandability
The selected base
capacity of the Low Temperature Activated Carbon (LTAC) plant is 5,000 tons per
year. This capacity is strategically chosen based on multiple technical,
operational, and commercial considerations, including:
- Modular Design Concept: LTAC systems can be designed
in modular units (e.g., 5,000 TPA per unit), allowing phased investment
and controlled expansion.
- Pilot to Commercial Scale: 5,000 TPA allows for
sufficient data acquisition for scale-up, while being cost-effective for
initial implementation.
- Utilities and Site Planning: This capacity is manageable
with medium-scale utility infrastructure and standard industrial land
(approx. 1-1.5 Ha).
- Market Feasibility: It meets entry-level
production volumes for industrial use in water treatment, air
purification, and chemical processing.
- Expandable Design: All utility systems, civil
foundations, and layout will be pre-planned for expansion up to 30,000
TPA. This will be achieved by adding parallel processing units without
shutting down the base plant.
2. Theoretical and
Scientific Principles
Low Temperature
Activation is a controlled pyrolysis and activation process using temperatures
ranging from 400–700°C (compared to 800–1000°C in traditional methods), using
either physical or chemical activation agents. The core principles include:
- Basic Chemistry:
- Carbonization: Removal of volatile compounds
from organic precursors (e.g., coconut shell, wood, or lignite).
- Activation Reaction:
- Physical: C + H₂O → CO + H₂
(Endothermic reaction)
- Chemical: C₆H₁₀O₅ (biomass) +
H₃PO₄ / ZnCl₂ → activated porous carbon + byproducts
- Material Balance: Example for 1 ton input
biomass:
- Feedstock: 1.00 ton dry biomass
- Losses (moisture, volatiles):
~0.50 ton
- Activated Carbon Yield:
0.30–0.35 ton (30–35%)
- Byproducts (tars, syngas):
0.15–0.20 ton
- Standards Applied:
- ASTM D2866 – Moisture Content
- ASTM D4607 – Iodine Number
- ASTM D1762-84 – Pyrolysis
Process Reference
- ISO 9001 / 14001 for Quality
and Environmental Management
Part 2: Engineering Design and System Components
3. Engineering
Basis: Process, Equipment, and Safety Systems
3.1 Process
Engineering
The production of
activated carbon using low-temperature activation follows several stages:
- Pre-treatment:
- Raw biomass (e.g., coconut
shells, sawdust) is dried to <10% moisture.
- Size reduction using shredders
or hammer mills to <10 mm particle size.
- Pyrolysis (Carbonization):
- Biomass is heated in the
absence of oxygen at 400–600°C.
- Volatile compounds are removed,
leaving a char-like material.
- Equipment: Rotary Kiln /
Horizontal Reactor with indirect heating (LPG, biomass gas, or electric).
- Activation:
- The carbonized material is
exposed to steam, CO₂, or chemical agents (e.g., H₃PO₄, ZnCl₂) at
600–700°C.
- This creates a porous structure
increasing the surface area (typically >800 m²/g).
- Equipment: Vertical activation
furnace or multiple hearth furnace (MHF), with steam injection.
- Cooling and Handling:
- Activated carbon is cooled
using a screw cooler or indirect air cooler.
- Product is then sieved and
transferred to storage.
- Packaging:
- Standard packaging in 25 kg
bags, 500 kg jumbo bags, or in bulk depending on customer.
3.2 Main Equipment
|
Process
Stage |
Equipment |
Material |
Remarks |
|
Pre-treatment |
Dryer, Crusher,
Conveyor |
SS304 / MS |
Dust protection
required |
|
Pyrolysis |
Rotary Kiln /
Reactor |
Refractory steel |
Temp 400–600°C |
|
Activation |
MHF / Fluidized
Reactor |
SS310 / Inconel |
Temp 600–700°C |
|
Cooling |
Screw Cooler |
SS304 |
Air or water cooled |
|
Sieving &
Packing |
Vibrating Screen,
Bagging |
SS304 / Mild Steel |
Based on product
mesh |
3.3 Materials and
Standards
- Material of Construction:
- Stainless steel SS304 for
contact surfaces
- Inconel or SS310 for high-temperature
zones
- Mild steel for structural and
non-contact areas
- Piping and Valves:
- Standard ANSI B31.3 piping
- Valves: gate, ball, and
butterfly type (as per media requirements)
- Safety and Support Systems:
- Fire and gas detectors (for
pyrolysis area)
- Explosion vents and pressure
relief valves
- Emergency shutdown (ESD) system
- Dust collection using cyclone +
bag filters
- Water spray system for fire
suppression
3.4 Compliance and
Standards Used
- ASME Section VIII (pressure
vessels)
- API 560 (heating equipment)
- IEC/NEC standards for electrical
classification (hazardous area zones)
- ISO 45001 for occupational
safety
Part 3: Process Automation and Control Systems
4. Automation
System Overview
To ensure safe,
efficient, and consistent operation of the Low Temperature Activated Carbon
(LTAC) plant, a semi-automated to fully automated control system is
implemented, covering mechanical, electrical, and instrumentation domains.
4.1 Mechanical
Automation
- Material Handling Systems:
- Automated conveyors and bucket
elevators controlled by VFD (Variable Frequency Drive) to maintain steady
flow of feedstock.
- Pneumatic actuators for
diverter valves to direct material flow.
- Kiln and Reactor Rotation:
- Rotary kilns use gear motors
with torque control for rotational stability.
- Furnace temperature controlled
by fuel feed rate and air flow regulation.
- Cooling and Packing Systems:
- Screw coolers and vibrating
sieves run on timer-based or sensor-triggered automation.
- Bagging lines with weight
sensors and auto-clamping mechanisms.
4.2 Electrical
Control Systems
- Power Distribution:
- MV/LV panels as per IEC 61439
standard.
- Main control room with
SCADA-connected MCCs (Motor Control Centers).
- UPS-supported power for control
systems and critical instruments.
- Control Panels:
- Local Control Panels (LCPs) for
each unit operation (dryer, kiln, furnace).
- Central PLC/DCS system in the
control room (Siemens, Schneider, or Rockwell preferred brands).
- Lighting and Emergency Power:
- Explosion-proof lighting in
hazardous zones.
- Diesel generator or backup grid
for emergency supply.
4.3 Instrumentation
and Process Control
- Temperature Monitoring:
- Thermocouples (Type K) and RTDs
installed in kiln, furnace, and cooling systems.
- PID controllers regulate burner
operation based on setpoints.
- Flow and Pressure Control:
- Steam and gas lines equipped
with mass flow meters and pressure transmitters (Yokogawa,
Endress+Hauser).
- Pressure safety valves (PSVs)
at critical points.
- Gas Analysis and Emissions:
- Online gas analyzers to monitor
CO, CO₂, and O₂ in flue gases.
- Emission stack with sampling
ports per EPA Method 5 or equivalent.
- Level Sensors:
- Silo and hopper level
monitoring using ultrasonic or radar level sensors.
- PLC/SCADA Interface:
- Real-time dashboard for
temperature, flow, pressure, and alarms.
- Data logging and report generation
for production and QA purposes.
4.4 Automation
Safety and Security
- Safety Interlocks:
- Emergency Stop (E-Stop) at each
operation station.
- Interlock between pyrolysis and
activation section to prevent unburned gas release.
- Fire Detection and Suppression:
- Heat detectors and flame
sensors in pyrolysis chamber.
- Automated CO₂ or water mist
suppression systems.
- Cybersecurity:
- SCADA firewall, VPN for remote
access, and daily backup protocols.
Part 4: Operational Safety, Environmental Impact, and Mitigation
5. Operational
Safety and Environmental Impact
A well-designed Low
Temperature Activated Carbon (LTAC) plant must meet both occupational health
& safety (OHS) standards and environmental regulations. These
two pillars are critical in assessing long-term feasibility.
5.1 Operational
Safety Aspects
A. Fire &
Explosion Risk
- Hazard: Fine carbon dust is highly
combustible and may cause explosions if suspended in air.
- Mitigation:
- Dust collection system using
cyclone and bag filters.
- Anti-static grounding and
bonding on equipment.
- Installation of explosion vents
(NFPA 68 standard).
B. High Temperature
Zones
- Hazard: Kilns and furnaces operate up
to 700°C.
- Mitigation:
- Insulation with ceramic wool or
refractory bricks.
- Interlocks to shut down burner
upon overtemperature.
- Restricted access during
operation.
C. Chemical
Handling
- Hazard: Use of activating agents like
H₃PO₄, ZnCl₂ (in chemical activation).
- Mitigation:
- Dedicated chemical storage with
secondary containment.
- PPE (Personal Protective
Equipment) requirement enforced.
- Eye-wash and emergency showers
installed.
D. Mechanical Hazards
- Rotating machines, conveyors,
and gear motors are guarded.
- Emergency stop buttons at every
key station.
5.2 Environmental
Impact and Mitigation
A. Air Emissions
- Source: Flue gas from pyrolysis and
activation.
- Control:
- Flue gas is treated using:
- Cyclones (for particulates)
- Scrubbers (for acidic gases)
- Activated carbon filters (for
VOCs)
- Designed to meet:
- USEPA 40 CFR Part 60
- EU Industrial Emissions
Directive (IED)
B. Wastewater
- Source: Washing of equipment, chemical
residue, cooling water blowdown.
- Treatment:
- Effluent Treatment Plant (ETP)
with neutralization, filtration, and biological stages.
- Reuse of treated water for dust
suppression or gardening.
C. Solid Waste
- Source: Ash, spent filter media,
rejected carbon.
- Treatment:
- Ash used in cement brick manufacturing.
- Rejected carbon can be
reprocessed or sold as fuel additive.
- All waste disposed per local
hazardous waste regulations.
D. Noise and
Vibration
- Soundproofing of crushers and
bagging areas.
- Vibration pads for rotating
equipment.
5.3 Sustainability
and Feasibility Indicators
- Carbon Neutrality: Use of biomass feedstock and
syngas recirculation reduces net CO₂ emissions.
- Energy Efficiency: Waste heat recovery from kiln
and flue gases.
- Compliance: Designed per ISO 14001
(Environmental Management) and ISO 45001 (Occupational Health and Safety).
By integrating safety
engineering and environmental management into the design and operation, the
LTAC plant becomes technically and environmentally feasible for both
industrial and urban settings.
Part 5: Reference Plants with Over 5 Years of Successful Operation
6. Real-World
Examples of LTAC Plants
To strengthen the
technical and commercial feasibility of the proposed LTAC project, it is
critical to examine reference plants that have already been in continuous
operation for at least five years. These references offer insight into
performance reliability, market acceptance, and scalability.
6.1 InnoCarb Plant
– Thailand
- Location: Chonburi Province, Thailand
- Feedstock: Coconut shell, palm kernel
shell
- Capacity: 6,000 TPA (expandable to
18,000 TPA)
- Technology: Low Temperature Activation
(500–650°C) with indirect heating rotary kiln
- Commissioned: 2016
- Highlights:
- Supplies food-grade activated
carbon to Japan and Korea.
- Achieved iodine number
consistently > 900 mg/g.
- Integrated solar drying reduces
biomass moisture content by 60%.
Website: www.innocarbon.com
6.2 EcoGreen Carbon
– India
- Location: Tamil Nadu, India
- Feedstock: Wood chips and agro-waste
- Capacity: 5,000 TPA
- Commissioned: 2017
- Technology: Multi-hearth furnace (MHF)
with chemical activation (ZnCl₂)
- Automation: SCADA-based monitoring,
semi-auto bagging
- Highlights:
- Reduced operational temperature
to 580°C using energy recovery.
- Registered ISO 14001-certified
facility.
Website: www.ecogreencarbon.in
6.3 Biokarb
Industries – South Africa
- Location: KwaZulu-Natal Province
- Feedstock: Hardwood sawdust
- Capacity: 10,000 TPA
- Commissioned: 2015
- Technology: Steam-based physical
activation, low-NOx burners
- Highlights:
- Advanced flue gas cleaning
system.
- Supplies to gold mining
companies for cyanide recovery.
- Achieved 85% capacity
utilization in 2021–2023.
Website: www.biokarb.co.za
These plants validate
the long-term reliability and commercial value of LTAC technology under various
feedstocks, climates, and market conditions. Each project demonstrates the
effectiveness of modular expansion, local feedstock sourcing, and automated
operation in maintaining performance over time.
Part 6: References
and Information Sources
7. References and
Technical Resources
To ensure the
credibility and reproducibility of this feasibility study, the following
references and resources were used. They include academic journals, industrial
standards, supplier datasheets, and case studies from operational plants.
7.1 Academic and Scientific
References
- Activated
Carbon: Classification, Properties and Applications
Author: Harry Marsh & Francisco Rodríguez-Reinoso
Publisher: Elsevier, 2006
ISBN: 978-0-08-044463-5 - Preparation
and Characterization of Activated Carbon from Agricultural Waste
Journal: Renewable Energy (Elsevier)
Link: https://www.sciencedirect.com/journal/renewable-energy - Thermochemical
Conversion of Biomass to Activated Carbon
Source: International Journal of Chemical Reactor Engineering
DOI: 10.1515/ijcre-2015-0087
7.2 Industrial Standards and
Guidelines
- ASME
Section VIII –
Pressure Vessel Design
https://www.asme.org - API
560 – Fired
Heaters for General Refinery Services
https://www.api.org - NFPA
68 – Standard
on Explosion Protection by Deflagration Venting
https://www.nfpa.org - ISO
14001:2015 –
Environmental Management Systems
https://www.iso.org/iso-14001-environmental-management.html - IEC
61439 –
Low-voltage switchgear and controlgear assemblies
https://www.iec.ch
7.3 Technical Suppliers and Product
Datasheets
- Yokogawa
Instrumentation
– Flow, pressure, and temperature sensors
https://www.yokogawa.com - Endress+Hauser – Process instrumentation
https://www.endress.com - Schneider
Electric – PLC
and SCADA solutions
https://www.se.com - Thermcraft
Inc. – Furnaces
and Kilns for low-temperature carbonization
https://www.thermcraftinc.com
7.4 Case Study Plant Websites
- InnoCarb,
Thailand
https://www.innocarbon.com - EcoGreen
Carbon, India
https://www.ecogreencarbon.in - Biokarb
Industries, South Africa
https://www.biokarb.co.za
7.5 Open Source and Government Resources
- US
EPA - Technical Factsheet on Activated Carbon
https://www.epa.gov/water-research/activated-carbon-treatment - United
Nations Industrial Development Organization (UNIDO)
Technical documents on biomass utilization:
https://www.unido.org/resources - National
Renewable Energy Laboratory (NREL) – Biomass processing resources
https://www.nrel.gov
Part 7: Summary and Practical Implementation Guide
8. Final Summary
and Project Implementation Guide
This final section
summarizes key findings from the feasibility study of a Low Temperature
Activated Carbon (LTAC) Plant and provides a practical guide for
implementing a modular, scalable project with a base capacity of 5,000 tons
per year, expandable to 30,000 tons per year.
8.1 Summary of Key
Technical Points
|
Component |
Details |
|
Technology Type |
Low Temperature
Physical Activation (450–650°C) using steam or CO₂ |
|
Feedstock |
Biomass-based:
coconut shell, woodchips, palm kernel shell |
|
Base Plant Capacity |
5,000 tons/year
(13.7 T/day) |
|
Expandability |
Modular expansion to
30,000 tons/year (6X growth) |
|
Core Process Equipment |
Rotary kiln, dryer,
steam generator, flue gas scrubber, bagging system |
|
Automation |
PLC/SCADA,
VFD-controlled conveyors, online gas analyzer |
|
Safety &
Environment |
Explosion vents,
ETP, emission control system, ISO 14001 & NFPA compliance |
|
CAPEX Range
(Indicative) |
$3M–$4.5M for base
capacity, depending on automation and location |
|
Market
Application |
Water purification,
gold recovery, food & pharma-grade activated carbon |
8.2 Phased
Implementation Plan
Phase 1:
Feasibility & Pre-Engineering
- Conduct biomass availability
study.
- Develop material and energy
balance.
- Prepare PFD, P&ID, I/O list,
and budgetary estimate.
- Submit to investors and
authorities for permitting.
Phase 2:
Engineering & Procurement
- Finalize detailed engineering
drawings.
- Issue RFQs to equipment suppliers.
- Select automation and
instrumentation vendors.
- Begin site preparation and
foundation work.
Phase 3:
Construction & Commissioning
- Fabrication and delivery of
process units (dryer, kiln, cooling line).
- Install mechanical, electrical,
and automation systems.
- Dry commissioning → Hot
commissioning → Performance testing.
Phase 4: Operation
& Optimization
- Begin commercial production.
- Monitor KPIs (yield, iodine
number, energy use).
- Use SCADA to optimize combustion
and activation cycles.
- Plan for expansion once 75–80%
utilization is reached.
8.3 Success Factors
for Feasibility
- Feedstock Availability: Long-term supply contracts or
plantation integration.
- Regulatory Approval: Air quality permit, wastewater
discharge compliance.
- Product Certification: Iodine number, ash content,
and mesh size validation.
- Market Channels: Secure offtake agreements with
buyers in water treatment, gold mining, or export markets.
- Technical Operator Training: Safety, process control, and
maintenance.
8.4 Practical Notes
for First-Time Investors
- Start Small, Scale Fast: 5,000 TPA is a manageable
pilot-commercial hybrid.
- Automate Early: Even basic PLC control can
save operating costs and improve safety.
- Design Modular Layout: Leave space and utilities for
future kilns, dryers, and bagging stations.
- Think Green: Integrate renewable energy
(e.g. biomass steam boilers or solar pre-drying).
- Consider Byproducts: Ash can be reused in cement or
fertilizer blends.
With proper design,
automation, safety, and market integration, an LTAC plant is not only
technically viable but also commercially attractive — especially in regions
with abundant biomass and growing demand for eco-friendly purification
materials.
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