Gasifier successfully install and tested
Technical Specification:
Parameter
|
Specification
|
Model
|
DG - 50
|
Gasifier type
|
Open top downdraft
|
Type of fuel
|
Biomass fuel (off cut wood, wood
chip, biomass pellets etc.)
|
Fuel consumption rate
|
20 – 50kg/batch
|
Fuel feeding interval
|
3 – 4 hrs
|
Biomass feeding system
|
Manual
|
Size of fuel
|
Diameter: 10mm – 50mm
Length: 10mm – 50mm
|
Moisture content of fuel
|
< 20 per cent (Wet basis)
|
Gas cleaning
|
Cyclone separator
|
Gas cooling
|
Condenser
|
Ignition
|
LPG torch
|
Introduction
Biomass Types
Biomass is a term for all organic material that comes from
plants (including algae, trees, and crops). Biomass is produced by green plants
that convert sunlight into plant material through photosynthesis, and includes
all land, and water-based vegetation, as well as all organic wastes. The
biomass resource can be considered as organic matter, in which the energy of
sunlight is stored in chemical bonds. Biomass has always been a major source of
energy.
Biomass types can be defined in different ways, but one
simple method is to define as:
·
Plant derived
·
Animal derived
The plant derived biomass resources can be further divided
into woody and non-woody biomass. Woody biomass includes trees and tree
residues, and energy plantation, etc., while non-woody biomass includes
agricultural residues, aquatic, and marine plants, etc. On the other hand,
animal-derived biomass can be considered as municipal solid waste, sludge, etc.
Biomass Gasification
Biomass gasification is the
process of partial combustion of biomass under controlled air supply, thus
producing a mixture of gases called “Producer gas”. It is a thermo-chemical
(chemical, and heat) process in which solid biomass is converted into a gaseous
fuel by a series of chemical reactions. Producer gas consists of a mixture of
combustible gases such as hydrogen (H2), carbon monoxide (CO), and
methane (CH4), and incombustible gases such as carbon dioxide (CO2),
and nitrogen (N2).
The producer gas obtained by the process of gasification can
have end-use for thermal application, or for mechanical/electrical power
generation. Producer gas can be used for decentralized power generation, water
pumping, and for a variety of thermal applications.
Operation and Maintenance of Gasifier
Following
the proper operation and maintenance procedures for a gasifier system is not
only important for ensuring the optimal operation, and long system life, but is
also necessary from the standpoint of health and safety.
Running
instructions
·
Feed the charcoal initially for the first run till the
nozzle height, and then feed the biomass fuel on the top of the charcoal till
the top of the gasifier. Feed proper size of biomass at specified moisture
content. This is a very important aspect, since oversize biomass can cause
bridging/blockage of the gasifier
· In order to economically, and safely
operate the gasifier, it is preferable that the operator keeps a logbook to record
the amount of biomass (and charcoal) which is fed into the system
Guidelines for
continuous operation
·
Charge the firewood every 4 hours, or as per the
requirements
· Remove the ash from the ash-pit at
every regular interval
Guidelines for
charging during operation
·
Ensure that while charging the gasifier, the main
blower is switched off
· Open the lid, or top door of the
hopper of the gasifier.
· Charge the fuel-wood pieces of
appropriate sizes into the gasifier hopper with the help of buckets.
· Ensure that the wood pieces are dry,
and not very big. Use the wood pieces of recommended size.
· Charge the required amount of wood
at once to have an easy operation.
· Charge the gasifier at regular intervals
of 4 hours, or as per requirements.
· Close the gasifier top
· Switch on the main blower.
· To re-charge, follow the above steps
repeatedly.
- Start the main blower, position the
air-valve up to half open, and also keep the flaring port open for at least 5
minutes so that the trapped gases inside the gasifier can be removed easily.
- Open the top covers and open the
ignition port cap.
- Switched on the air blower for 2 – 3
minute to flush the gas trap in the gasifier
- Ignite the biomass fuel using lpg
torch until the biomass ignite
- Close the top cover
- On the blower and regulate the flow
rate of blower using valve
- After 5 – 10 minit, ignite the syngas
at flare port. Regulate airflow rate of the blower till the gas gets ignited
and make sure the flame sustains for 10-15 minutes in the flare-port
- Transfer the gas towards cleaning & cooling train:
When the good quality gas starts coming in the flare port, open the valve of
the cleaning and cooling train, and close the valve of the flare-port. Allow
the gas to pass through the trail so that it can be cleaned as well as cooled
before feeding it for example in to the gas engine or gas burner
STANDARD OPERATING
PROCEDURE
BEFORE OPERATION
1.
Safety first.
2.
Make sure the equipment is in good working condition.
3.
Clean the ash, char and unburned feedstock inside the gasifier before feeding
the new feedstock.
4.
Make sure all the thermocouple are connected and working properly.
5.
Make sure blower is working properly.
6.
Switch ON blower to check airflow inside gasifier. OPEN all valve and make sure
there is air flow. Then switch OFF the blower.
7.
Weight and add in the feedstock inside the boiler.
8.
For starting the ignition make sure the feedstock does not cover the ignition
hole.
HOW TO OPERATE
1.
CLOSE all valves. Refer to Figure 1 and 2.
2.
Switch ON all equipment (blower, temperature reader and fan).
3.
START ignition through the ignition hole. When the feedstock start to burn STOP
ignition.
4.
Supply and control the air volume flow rate on the rotameter. Use Valve 2 to
control air flow. Start with airflow 20m3/h. Air flow depends on
type of feedstock.
5.
Add feedstock inside the boiler. Make sure NOT to look inside the firebox
directly as the heat will cause harm. CLOSE the boiler.
6.
To flare gas OPEN Valve 3 or 5. CLOSE the valve to stop flare.
7.
Connect the sample gas to the gas analyser. ON valve 4 to collect the sample
gas.
8.
Collect the gas composition data in the gas analyser.
AFTER OPERATION
1.
Stop the air supply.
2.
Collect the ash and char after the system is cooled down.
3.
Housekeeping.
Maintenance of the
gasifier
Along with proper operational procedure, regular system
maintenance is also required to keep the system in a condition fit for long and
continuous operation.
Daily maintenance
·
Clean ash-pot of the gasifier
·
Clean the heat exchanger by removing the dust and
liquid collected in it by opening the end-plug from bottom of the heat
exchanger
· Clean the cyclone separator by
removing the dust collected in it by opening the end-plug from bottom of the
cyclone separator
Safety measures
Some measures that need to be taken to ensure the safety of
operators as well as the equipment are listed below:
·
Wear suitable personal protection equipment (face
mask, google, shoe and etc.)
·
Make sure there is no flammable material nearby.
· Place a fire extinguisher, of appropriate size, and
capacity, on a wall near the gasifier. Ensure that the extinguisher is easily
accessible. It is also advisable to install a CO (carbon monoxide) alarm near
the gasifier system.
· While charging fuel, do not lean, and look inside the
gasifier hopper through the fuel-charging door. Combustible gases can suddenly
come out, catch fire, and cause injuries.
· Ensure that the blower is not connected to the
electricity supply, and the air supply valves are in closed position while
charging fuel inside the gasifier.
· During power cuts, close all air supply valves, and
open the gas flare pipe. Close the gas flare pipe after releasing the
accumulated gas in the gas duct.
·
Do not look at the firebox through the air nozzles
with the naked eye when the end-plugs are removed from nozzles. This is because
sometimes flames shoot out through them.
· Empty the ash pot tank only after ensuring that the
fire in the firebox chamber has been extinguished completely.
· If the body of the gasifier is hot,
do not sprinkle it with water to cool it because sudden cooling damages the
firebox lining.