Biomass Power Plant Boiler is often the fully automatic biomass boiler system which deliver natural biomass or pellets to match the heat demand of the biomass fired boiler for the power plant. Generally, Biomass Power Plant Boiler shares the similar structure with coal fired boilers and behave like coal or gas boilers. but biomass power plant boiler has higher and larger furnace to ensure the sufficient combustion of biomass fuel as well as full load operation compared with coal fired boiler.

Biomass and bio-fuel like crop straw, wood chip, sawdust, peanut shell, corn cob, rice straw, rice husk, straw bran, tree branches and leaves, hay and compressed pellet can provide clear and renewable energy solutions for large companies or power plant.  Compared with oil, electricity and gas boiler, the operation cost of  biomass power plant boiler decreases by 60%, 40% and 70% respectively.

Biomass Power Plant Boiler detailed parameters

Rated evaporation capacity                         30t/h

Rated working pressure                               4.1MPa

Feed water temperature                               104℃

Rated steam temperature                            385℃

Radiation heating area                                 168.5m2

Slag-cooling tube heating area                   35.94m2

Cooling flue duct heating area                    115 m2

High-temp superheater heating area        163.715m2

Middle-temp superheater heating area    204.99m2

Low-temp superheater heating area         163.715m2

High-temp economizer heating area        267.93m2

Air preheater heating area                          678.3m2

Low-temp economizer heating area         535.86m2

Hot air temperature                                     210℃

Blow-down rate                                              4%

Flue gas temperature                                  146℃

Design efficiency                                         82.77%

Fuel consumption                                       9457.95kg/h

How to Operate Biomass Power Plant Boiler
How Operate Biomass Power Plant Boiler

1. Biomass power plant boiler startup

1.1. Inspection and test before biomass steam boiler startup

Specific inspection contents before operation and normal ignition of industrial biomass boiler:

(1) The inspection of combustion chamber and internal flue duct of biomass boilers.

  1. The combustion chamber has no coke residue and sundries leaving after maintenance: furnace wall and furnace arch should be intact, no crack and burning loss.
  2. The stoker side cooling box has no coking, soot formation, support is strong has expansion clearance.
  3. Manhole, observation hole and furnace door are tight.
  4. Water wall, superheater, economizer and air preheater are normal in shape, anti-abrasion plate is complete and solid, and has no damage.
  5. There is no blockage in the secondary air nozzle and the measuring points; the coating and water wall are intact, the coal feeding port has no coke residue, the air door switch is flexible and the opening indication is accurate.

(2) The inspection of dust collector for biomass power plant boiler

  1. staircase and platform are solid and no sundries.
  2. inside is complete, smooth and clean.

(3) The inspection of the wind box of biomass power plant boiler

  1. air door switch is flexible and indicating correctly, and the ash discharge pull rod is complete, and the switch is flexible and tight.
  2. Each air chamber blast pressure gauge should be clean and normal, no dust, manhole shall be tight.

(4) The inspection of the silo of biomass power plant boiler

  1. silo is intact, no sundries and full fuel.
  2. vibrating feeder is good.
  3. feeding device is well driven, the baffle adjustment is flexible, and the fuel level is smooth. The feeder is normal and there is no sundries in the hopper.

(6) Check whether the steam water sampling device is good.

(7) Check whether the lighting is adequate, emergency lighting is good.

(8) Check whether the header hand hole cover, drum hole is intact; the expansion indicator is complete, instructions is correct.

(9) The inspection and test of biomass power plant boiler grate

  1. grate is flat and complete with no sundries.
  2. glede iron is flat, complete and firm.
  3. The oil pipes for lubrication part shall be clean and complete, enough lubricating oil and the cooling water of the front and rear axle is unblocked.
  4. the protective cover of grate, the grounding wire is intact, and the oil level is normal.

Test of grate:

  1. starts the grate to carry out each speed test, and the motor current is normal.
  2. grate rotates flexibly and has no astringent and other phenomena.
  3. glede iron should be flexible and pressed on the grate.
  4. control device operates flexibly.

(10) The inspection and test of rotating machinery of biomass power plant boiler

  1. protective cover is complete and solid, and the belt is complete, tightness is proper and the anchor screws are solid.
  2. all bearings lubrication oil is sufficient, the cooling water is unblocked, and the thermometer is complete.

Test of rotating machinery:

  1. no noise. friction and impact.
  2. the direction of rotation is correct.
  3. bearing temperature is no more than 70 degrees, and vibration is no more than 0.08mm.

(11) The inspection and test of biomass power plant boiler fan

  1. anchor bolts is solid, the protective cover is intact, the rotor and the shell has no friction.
  2. bearing lubrication oil level is normal.
  3. baffle switch is positioned correctly, and the adjustment mechanism is flexible and easy to use.
  4. The cooling water of the bearing box is unblocked.

Fan test

  1. close the fan inlet baffle, start the fan to full speed, check whether the bearing and rotation part has vibration, friction and other abnormalities.
  2. the direction of rotation is correct.
  3. gradually turn up the air door and load test. The motor current should not exceed the rated value. The vibration should not exceed 0.05mm, and the bearing temperature should not exceed 80℃.

(12) Biomass power plant boiler fan interlock test

  1. fan is put into interlock after the test is normal.
  2. starts each fan in sequence, test with the accident button and manual stop respectively, after the test is finished, the interlock is normal, put the start handle of each fan to the stop position.
  3. Interlocking test of fan and coal feeder.
Biomass Power Plant Boiler

(13) Biomass power plant boiler steam water pipeline and valve check

  1. support hanger is in good condition and the pipe can expand freely.
  2. thermal insulation is well, and its surface is clean, the medium flow direction and color meets the requirement.
  3. valve is well connected with the pipe.
  4. handwheel is complete and solid. The door rod is clean, no bending and rust, the switch is flexible, and the switch direction is correct.
  5. electric door test is qualified, the switch is flexible and tight.

(14) check the water meter of biomass power plant boiler

  1. water level meter steam water connecting pipe insulation is good.
  2. water level gauge is clear, and the valves are tight and leak-free, and the switches are flexible.
  3. water level gauge has a good protective cover, and its scale is correct. The high and low limit water level and normal water level are clearly marked.
  4. lighting is well.

(15) Pressure gauge inspection of biomass power plant boiler

  1. the pressure gauge is clear, and there is a high and low permitted fluctuation range on the pressure gauge.
  2. the pointer is zero, and the calibration is qualified, and the lighting is enough.

(16) Check safety valve of biomass power plant boiler

All the accessories of the spring safety valve are complete.

(17) Check the control panel of biomass power plant boiler

  1. all instruments, signals, operation switches are complete and reliable.
  2. plate is regular, mark is complete, and the name is correct.
  3. indicating light and lamp cover is complete and the color is correct.
  4. contact device, alarm and signal are good.
  5. remote control is flexible and reliable.
  6. microcomputer information display is correct.

(18) The inspection and test of slag remover of biomass power plant boiler

  1. check every component, remove the dirt, no jam.
  2. the oil in the gear governor box is clean and no sundries.
  3. the connecting screws is not loosened.
  4. cooling water is unblocked, deflector hole has no block.
  5. overload safety clutch should be in good condition.
  6. No sundries around the equipment.

Test run of slag remover

  1. start the slag remover for 2 hours, the motor and fuel tank are not heated, the parts are not loose, and the motor current is no more than 2.1A.
  2. After 2 hours of trial operation, be reversed again, and it will be eligible and put into operation after trial operation is normal.

(19) Biomass power plant boiler slag conveying belt check

  1. motor foundation screws are not loose, grounding wire is solid.
  2. belt should be without fracture, and the transmission belt is intact.
  3. grate governor box has no damage, oil is sufficient.
  4. main and slave roller has no shaft swaying.
  5. slag conveyer belt has no person or sundries.
  6. belt guardrail and protection net is complete.

Slag conveying belt test run

  1. start belt conveyor, the rotation parts are running normally without noise, and the direction of rotation is correct.
  2. belt has no deviation, and carrier roll is flexible.
  3. all the rotation parts should have sufficient lubricating oil.

(20) Valve position of biomass power plant boiler

  1. steam system: electric main valve, air exhaust primary door open, electric main steam valve bypass valve, air exhaust electric valve, primary isolation valve and its bypass valve close.
  2. water feed system: water valve and its bypass valve and water supply automatic adjustment valve close: water supply adjustment valve, economizer inlet valve and reverse circulation valve (close when feeding water) open.
  3. desuperheating water system: desuperheating water inlet valve, adjust valve and air valve close, exit valve opens.
  4. water discharge system, regular blowdown total valve, continuous blowdown primary valve, accident water discharge primary valve open, each header regular blowdown valve, continuous blowdown secondary valve, accident water discharge electric valve and third valve closed.
  5. drainage system: the drain valve on the front pipe of the main steam valve of the steam turbine and superheater open, the drain valve of the desuperheater open, the drain opening in front of the mother tube isolation valve, and the drain closing after the valve.
  6. steam and boiler water sampling valve and dosing valve open.
  7. water level gauge: on site water level gauge, electric contact water level gauge, and differential pressure gauge steam valve and water valve opens.
  8. water feed pipe air valve should be closed and steam conduit air valve closed, superheater header air valve should be closed.
  9. pressure gauge: primary valve opening for each pressure gauge; primary valve opening for flow meter.
  10. drum air valve and water feed pipe air valve open, water feed pipe air valve closed after water.
  11. each fan inlet baffle, second, third, fourth and fifth air chamber valve closes, first air chamber valve opens 1/2.
  12. bag filter is put into operation and wet scrubber water valve opens.
Operate Biomass Power Plant Boiler

1.2 Preparation before biomass power plant boiler start

1.2.1. contact with relevant people to prepare for the biomass power plant boiler.

  1. electrical on-duty personnel: electrical equipment power on.
  2. mooring on-duty personnel: water feed pipe supply water, and open the drain valve on steam pipeline.
  3. thermal on-duty personnel: the instruments and operation devices are in working condition.
  4. chemical on-duty personnel: test boiler water quality.
  5. fuel on-duty personnel: feed fuel in the silo.

1.2.2. after the inspection is finished, if the drum has no water, feed the qualified deoxygenated water in the economizer, the temperature should not exceed 90 degrees C, and the feed water time should be extended if it is over 90 degrees C. The water supply should be carried out slowly, not less than 1 hours in summer, but not less than 2 hours in winter.

1.2.3. In the process of water supply, the air valve of economizer pipe is closed after water.

1.2.4. In the process of water supply, should inspect the drum, the hole, valve and flange of the header. If there is any water leakage, stop the water supply.

1.2.5. when the water level is up to 30mm, the water supply is stopped and the water level meter is checked. If the water level is changed, the reason should be found out, and the reverse circulation gate should be opened after the water supply is finished.

1.2.6. if the boiler has water, adjust the water level to the ignition level, if not qualified, handle according to the requirements of chemical personnel.

1.2.7. open the ID fan five minutes before ignition and suck out residual air in the furnace.

1.2.8. grate is laid up with biofuels, and the ignition tools are prepared.

1.2.9. prepare the ignition articles.

1.2.10. after it is ready and report to the shift chief-operator.

To Operate Biomass Power Plant Boiler

1.3 Biomass power plant boiler ignition and pressure rise

1.3.1 after receiving the ignition command of the shift chief-operator, the fireman open the operation ticket. After it is audited by the monitor, carry out the ignition and notify the person concerned.

1.3.2. cold ignition to rated pressure, the time required is 2-3 hours, the summer is no less than 2 hours, and the winter is no less than 3 hours.

1.3.3. in order to make the boiler be heated evenly, during the ignition process, the temperature of the furnace should be increased slowly and evenly, and the superheater drainage should not be shut down so as to avoid the damage of the superheater due to high temperature in the process of rising pressure.

1.3.4. starts the ID fan according to the ignition status of biomass fuel, and maintains the negative pressure 20-30Pa.

1.3.5. starts the FD fan according to the ignition of the fuel, propel the grate movement at a proper speed, and gradually open the air door of air chamber with the grate movement and combustion propulsion.

1.3.6. in the process of ignition, monitor the indicator of the expansion indicator, check the tightness of valve, flange and other junction surface, if any abnormal, find out the cause, eliminate, and then rise the pressure.

1.3.7. from the ignition to the rated pressure should be carried out by the water cooling wall header, discharge four times, that is, half an hour after the ignition; 0.25-0.35MPa; 2.0MPa discharge the water respectively, and when the steam pressure rises to 0.05-0.1MPa, wash the water level meter and check the correctness of the water level meter.

When the pressure rose to 0.15-0.2MPa, inform the thermal to wash the pressure gauge pipe.

When the pressure rose to 0.3MPa, inform the repairman to fasten the screws.

When the pressure rose to 2.5-3.0MPa, inform the chemical personnel to make sampling and analysis of steam quality.

When the pressure rose to the rated pressure, steam temperature at above 350 degrees, make comprehensive inspection of equipment.

1.3.8. Adjust the steam pressure, temperature, water level to stable, report to the shift chief-operator.

The whole pressure rise process is controlled for about 2-3 hours, and the temperature rise speed should be uniform, monitor and record.

The pressure rise operation of the biomass power plant boiler:

  1. when the steam pressure rises to 0.05-0.1MPa, wash the drum water level gauge and check whether the other water level gauge is consistent with the drum water level gauge.
  2. when the steam pressure rises to 0.15-0.20MPa, turn off the air valve of the drum, the drain valve of the desuperheater header, and the air valve of the superheater and desuperheater.
  3. when the steam pressure rises to 0.25-0.35MPa, the water cooling wall lower header blowdown and discharge water, pay attention to the water level of the drum. When feeding the water, the reverse circulation valve should be closed, and inform the thermal workers to wash the pressure gauge tube and the instrument tubes.
  4. when the steam pressure to 0.30-0.40MPa, inform the maintenance to fasten the screws, record the expansion indicator.
  5. when the pressure rose to 2MPa, keep the pressure stable, to conduct a comprehensive inspection of boiler.
  6. when the pressure rose to 2.5MPa, make an intermittent blowdown, wash the water level gauge, check water level gauge, record the expansion indicator.
  7. when the steam pressure rises to 3-3.5MPa, proofread the water level meter, and inform the chemical to test steam quality, make overall inspection of the boiler, adjust the superheater steam temperature, stabilize the combustion.