- Why are we doing the project?
- Do I really know what I’m doing?
- Do the stakeholders really care?
- Who is doing what? Why? And when?
- Should I really get involved in all activities?
- Have I improved?
- Am I trying to deliver at any cost/risk?
- Is this bringing value to the stakeholders or project owner?
New Webinar here.
Expected biomass projects in Europe 2020-2021 (total > 6 million ton/year)
|EPH||Lynemouth||396||Dedicated 100%||Commissioning Ranged 57-85% weekly availability
|MGT||Teeside||299||Dedicated 100%||Planned 31 July 2020||1-1.2mn t/yr|
|RWE||Amer||630||80% by 2020||38% in Q3 2019||1.7-1.8mn t/yr|
|RWE||Eemshaven A & B||777||15%||“Almost at 15%” in
|Uniper||MPP3||1.1GW||15%||November 2019 start||200,000-250,000 t/yr|
|Onyx Power||Rotterdam||731||10%||Offline until April 2020||500,000-550,000 t/yr|
Expected biomass projects in South Korea during 2020-2022 (total > 4 million ton/year of pellets and chips)
|Company||Plant||Capacity (MW)||Start-up||Wood pellet (t/yr)||Wood chip (t/yr)|
|Korea South East Power (Koen)||Yeongdong unit 2||200||June 2020||900.000|
|CGN Daesan Power||CGN Daesan Power||109||December 2020||500.000|
|GS EPS||Dangjin unit 2||105||December 2020||300.000||200.000|
|SMG Energy||SMG biomass power
|100||delayed to June-July 2021||430.000|
|Gwangyang Green Energy||Gwangyang biomass
|220||July 2022 (delayed)||480.000||528.000|
|Korea Midland Power||Gunsan Bio||200||December 2022 (delayed)||800.000|
Source: Biomass markets adjust to challenging times. Steady growth in demand.
Webinar – 19 March 2020. Public Argusmedia.com Market report
You should know certain things about your plant. Here’s a quick list of common questions.
1. What’s your normal operating pressure/temperature?
2. What pressure/temperature are the safety/relief valves set at?
3. What’s the capacity of (each) boiler?
4. What’s your normal feed water/return temperature?
5. What fuels do you fire?
6. What’s the capacity of your fuel storage?
7. Where does your fuel come from? Are there alternate suppliers?
8. What is the turndown for each boiler?
9. What’s your electrical power (208/230/460, 3 phase)?
10. How reliable is your electric power? (How many interruptions and their length in an average year)
11. What’s your normal compressed air supply pressure?
12. What’s your peak load? Peak day? Peak Hour?
13. What’s your normal winter load?
14. What’s your normal summer load?
15. What’s your minimum load?
16. What’s your water supply pressure?
17. What’s the normal hardness of your water supply? Of alternate water supplies?
18. Where does your water come from? Do you have an alternate supply for water?
19. (How many boilers do you run in the summer?)
20. (How many boilers do you run in the winter?)
21. (How frequently do you switch boilers?)
22. What’s your condensate return system leakage percentage?
23. What’s your normal condensate temperature?
24. Is your condensate return pumped?
25. What does your blowdown drain to?
Source: Boiler operator’s handbook by K. E. Heselton
The grate boiler analyzed is fired primarily with bran, which is a residue from the milling of wheat grain (outer shell of wheat) used for the production of ethanol. Bran has an ash content up to 7%wt. dry basis.
The vertical type boiler is installed in the largest bioethanol factory in Wanze, Belgium. The boiler was built 11 years ago, in 2009. Bran can be used for animal feed, but also for generating energy. The bran boiler was unable to supply all the required steam for the production plant so it was decided to use natural gas (n-gas) for the remaining energy input. The n-gas is utilized in an external superheater and the flue gas is led to the bran boiler. The plant has a capacity of burning 20 tonnes bran/hour, for a total of 75 MWth, 25 MWel (100 ton/h steam at 92 bar, 520°C including the n-gas external SH). The bran is delivered to the boiler-dosing silo and fed into the boiler with feeding screws.
The combustion takes place on a water-cooled vibrating grate, suitable for the 13.5 – 17.0 MJ/kg moist and high ash bran. The grate consists panel walls mounted on leaf springs. These panels are activated in pairs, in counter phase, by a vibrating unit. Primary combustion air is injected through holes drilled in the fins of the grate panel. The flue gas from the n-gas external superheater is mixed into the bran boiler in front of the convection section reaching a final flue gas temperature of 520°C. The bottom ash is removed with a submerged chain conveyor and carried to an open ash pit.
In order to avoid clogging, the boiler is designed with two empty boiler passes to ensure sufficient cooling of the fuel gas before entering the convection part. In that way, ash will deposit in solid form. The bran fuel is expected to generate fouling and slag on the walls in the empty boiler passes, which have therefore been equipped with water soot blowers. Downstream of the economizers, baghouse filters were installed to remove the fly ash particles from flue gas. To reduce the emissions of SO2 and HCl, NaHCO3 particles were injected before the baghouse filters.
The plant was initially operated with pure bran. However, after successful operation of a few months, according to published literature, the baghouse filters were found to be blocked by “sintered” fly ash, which could not be removed by pressurized air and hindered the continuous operation of the plant. In addition, severe ash deposition was observed in the economizers of the plant, with flue gas temperatures of 380-180°C. To minimize these problems, the plant was operated with the addition of 5-8 wt % CaCO3. It appeared that the baghouse filter problem was mitigated by addition of CaCO3 and by changing the operational condition of the filter, whereas the ash deposition problem in the economizers still appeared occasionally, based on the reported published return on experience.
BIOFACT Dashboard is a tool to predict ash related risks in combustion units. The tool has been applied to bran, and the results is reported in the following.
It should be noted that the composition of the bran used on the grate-fired plant varied over time, and deviates from that shown in the BIOFACT Dashboard. Moreover, CaCO3 was applied in the boiler. Due to these factors, the full-scale results can only be compared with the results from predicted data qualitatively. Emission guarantees out of the boiler (6% dry O2) according to boiler manufacturer:
- NOx: 278 mg/Nm3 (including primary mitigation measures)
- Dust: 18 mg/Nm3 (after flue gas treatment)
- HCI: 25 mg/Nm3 (after flue gas treatment)
- SO2: 179 mg/Nm3 (after flue gas treatment)
Today, the biomass-fired boiler uses bran, biogas and a by-product derived from distillation such as fusel oil.
Great interactive article by authors S.Evans and R.Pearce.
The BIOFACT Ash Chart is a high quality synthetic plot of the amounts of the inorganic fraction for 500+ solid biomass fuels. The fuels are belonging to different classes (20+) such as stem woods, barks, straws and grasses, shells and husks, fruits and residues, animal and industrial wastes. Median values for fossil fuels are included for comparison. It is useful to expand your overview on the renewable fuels portfolio.
Request us a high quality PDF suitable for A1 printing, email at firstname.lastname@example.org.
- Slag: Characteristic ash removed from furnace walls
- Bottom ash: Ash removed from the bottom of the furnace
- Clinker: Large piece of bottom ash that must be broken up before transport
- Fly ash: Ash carried by the flue gas into the backpass region and beyond
- Popcorn ash: Characteristic ash collected in economizer and air heater hoppers
- Dust: Fine ash particulate
- Hydro ejector: Venturi device that pulls bottom ash into hydraulic transport system
- Water bin: Dewatering bin for removing water from bottom ash
- Hydrovactor: Venturi device that provides vacuum source for pneumatic transport
- Airlock value: Two chamber device for feeding ash into higher pressure transport line
- Materials handling valve: Valve that admits flyash and air flow into vacuum transport line
- Collector: Ash/air separator and transfer tank from vacuum system to silo
- Transporter: Fly ash collection and aeration vessel for dense phase pneumatic transport
- Vacuum/pressure transfer station: Collection and transfer vessel from vacuum line to pressurized line in combination vacuum/pressure pneumatic system
- Drag chain: Primary mover in mechanical drag conveyor system
- Flights: Attached to drag chain to push ash along stationary platform
- Unloader: Device to unload dry ash storage silo into transport vehicles
- Conditioner: Adds water to flyash during unloading to minimize airborne dust
- Pugmill: One version of combined silo unloader/conditioner