8/7/2019 liaoyuan_power_plant

1/2

Liaoyuan Biomass Power Plant ProjectJilin Province, China

Introduction

Liaoyuan power plant is one of 20 biomass power plants to havebeen installed by DPCleanTech in China from 2006 to 2009.This 30MWe straw fired power plant in Liaoyuan county of Jilinprovince is operated by DPCleanTech sisters company NationalBio Energy (NBE), along with 10 other straw fired power plantsof 12 or 30MWe.

Plant Performance

The plant has an installed capacity of 30MWe. It runs on locallysourced fuels mainly from agriculture residues such as cornstraw. In the straw fired boiler, so called hard fuel such as woodchips can be fed via the auxiliary silo contributing up to 35%share of the fuel. The plant consumes more than 160,000 tons ofstraw per year and reaches an availability of 7800h/y.

High Efficiency

The straw fired steam boiler operates with high steamparameters at 92 bar and 540oC resulting in a net overall plantefficiency of more than 32%.

Straw Storage

The fuel handling system utilizes large or small square straw balesand has been made flexible to burn auxiliary fuels thus securingthe fuel availability. The straw storage of the plant is designed for acapacity of more than 7 days.

Steam Boiler

The straw firing system and steam boiler island are based on aDanish technology by Bioener which has been recently acquiredby DPCleanTech holding. The technology has since beenadapted and improved by DPCleanTech.

The design of the steam boiler together with the proper selectionof materials counteracts the fouling and corrosive effects of the

straw fuel.

Flue Gas Cleaning

The steam boiler is provided with a fabric filter for removal ofparticulate matters so all emissions are below the limit valuesstated in the planning permission.

Power Plant Specification

Location ................................... Liaoyuan, Jilin, China

Installed capacity ............................................. 30MWe

Internal consumption ............................................ 10%

Boiler designer and manufacturer ............ DPCleanTech

Fuel .......................................................... Corn straw

Calorific value (9.4% moisture) ....................... 14MJ/kgFuel consumption .............................................. 25tph

Auxiliary fuel ... Wheat straw, tree branch, peanut shell, husk

Plant Availability .............................................. 7800h/y

Steam production ............................................. 130tph

Steam outlet temperature ................................ 540 deg

Steam pressure ................................................. 92 bar

Feed water temperature ................................... 220deg

Boiler efficiency .............................................. >93.1%

Plant efficiency ................................................... >32%

A high-efficiency, turnkey straw-fired power plant with advanced steam conditions

8/7/2019 liaoyuan_power_plant

2/2

Technical Description: Straw Fired Boiler

Fuel supply and handling

The plant consumes approximately 160,000 tons of straw peryear. The straw is supplied by local farmers growing crops withina 50 km radius of the plant site. The bales of straw arrive at theplant on trucks which deliver the fuel to the straw barn storagearea. The straw bales are fed onto automatic conveyors whichtransport the fuel to the boiler building. When the bales arrive at

the feeding system, a scarifier cuts the twines so the straw balesmay be loosened and sliced before being fed into the boiler atthe required and controlled flow rate.

The combustion process

The straw is led to the boiler through a stoker and is thencombusted on a water-cooled vibrating grate under carefullycontrolled conditions; the vibrating movements regulate thestages of combustion. The vibrating motion occurs in cycleswhich alternate between 1.5 3 minutes for a period of 3 5seconds at a time. Part of the combustion air is fed to thefurnace from beneath the grate and further combustion air isled to the furnace through nozzles situated above the grate. The

first section of the grate into which the straw is fed, is subject tohigh turbulence in order to help the straw in releasing its volatilematter, this corresponds to 50 - 60% of the straws energy. Thefuel ash and slag are transported by the vibrating movementdown the grate to the slag fall along with the final burn out of the fuel.

Specially designed boiler

The steam boiler is a water tube boiler with hanging superheaterswhich produce 130 tons of steam per hour at 92 bar and 540 oC.The boiler design has been specially developed for straw firingto work with the high temperature and high pressure. The steamproduced is used in a conventional steam cycle turbine. The plantsupplies approximately 200,000MWh of electricity to the national

grid annually. The flue gas, having been cooled in the boiler, iscleaned in a fabric filter before being discharged through thestack.

1. Chain conveyor

2. Seal gates

3. Dosing unit

4. Scarifier

5. Fire dampers

6. Stoker

7. Water cooled duct

8. Vibrating grate

9. Stag conveyor

10. Combustion Chamber

11. Air preheater

12. Induced draught fan

13. Forced draught fan

14. Combustion air intake

15. Air preheater

16. Preheated combustion air

17. Feedwater tank18. Steam drum

19. Economizer

20. Superheater1

21. Superheater2

22. Superheater3

23. Water for atemperators

24. High pressure steam to turbine

25. Aircooled condenser

26. Flue gas cooler

27. Gas suspension Absorber

28. Fabric filter

29. Wood chip silo

30. Wood chip

31. Straw barns

32. By product and ash handling

33. Natural gas