BF-TYPE BOILERS FOR BIOMASS COMBUSTION

Transcription

1 BF-TYPE BOILERS FOR BIOMASS COMBUSTION U Školky 357/14, Plzeň Ident. No.: Tax No.: CZ Tel.: Tel.: Fax.: invelt.praha@invelt-servis.cz Registered at Regional Court in Plzeň, section C, enclosure 5198 Česká spořitelna, a.s. Plzeň Account No.: IBAN CZ

2 INVELT SERVIS s. r. o. supplies power generating units including boilers along with the complete related equipment. The technological equipment described above is intended for the utilization of biomass mainly on the basis of wood chips and bark as the fuel being burnt in the boiler. The complete supply starts with the outer fuel economy the part representing a steel container at the fuel yard. The supply ends with the output smoke fan flange. The supply scope can of course be modified in accordance with the Client s requirements. The designed technology provides for the fuel incineration on a stationary grate using the fluid technics principles. The solution arises from experience, knowledge of construction and operation of the biomass incinerating equipment being considered in the proposed conception. This is an approved up-to-date technology guaranteeing the fulfilment of required parameters and emissions. The technology shows high efficiency, low self consumption, high operation reliability along with low maintenance costs. The equipment provides for continuous automatic output regulation in a wide regulation range. The complete supply is divided into six basic operation units: Boiler and Accessories Outer Fuel Transport Inner Fuel Transport Inner Ash Transport Flue Gases Exhaust and Cleaning Equipment Instrumentation and Control System (I & C) Electric Installation EQUIPMENT DESCRIPTION Boiler with Accessories The boiler is designed as a one drum boiler with natural circulation, three-draughted with a divided spring-back second draught. The boiler is embedded in a steel supporting structure. Two stationary grates are placed in the bottom part of the furnace; each of them being provided with a side ash withdrawal. Page 1

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4 Primary burning air and fuel are supplied into the grates area. Inert material making the fluidized bed stable and increasing its thermal capacity is added to the fuel biomass in case of need. Secondary combustion air for afterburning of flammable gases from the fluidized bed and the fly ash portion outgoing therefrom is supplied through nozzles into the furnace above the grates. Secondary air is supplied on two height levels always from the front wall and the rear wall of the combustion chamber. There is a high combustion chamber above the grate being created by the membrane walls. In the middle part of the combustion chamber, two start-up monoblock burners for gas or light fuel oil are placed. In the upper part under the ceiling of the combustion chamber desks of the output radiant shoot, superheaters are placed. Flue gases flow next into the second boiler draught where further heat exchange surfaces are placed gradually the evaporator bundle, the convection superheater blocks and the economizer blocks. As the last additional surfaces, the air heater blocks are placed being situated at the end of the second draught and in the third draught of the boiler. Two vertical blowers are placed in the place of the heating surfaces blocks in the second draught providing cleaning in the working condition of the boiler by means of reduced steam from the boiler. Page 3

5 The fly ash being captured in the hopper underneath the evaporator bundle returns back into the grates area for afterburning. Air supply being necessary for the boiler operation is provided by two fans a primary fan and a secondary fan. Air is supplied to the fans through the suction air ducts being fitted with a noise softener and flaps in the scope needed. The suction air ducts split up from the common inlet part into a primary part and a secondary part. A denitrifying device reducing NOx emissions by means of the SNCR method can be installed at the boiler if needed. Page 4

6 Outer Fuel Transport The supply starts with a steel storage tank with an underpassable floor. The movement is provided by hydraulic cylinders. The storage tank is placed on a concrete base. The fuel handling on the outside yard is provided by means of mobile technics. The fuel being brought can either be directly thrown into the storage tank or stored on the yard. The fuel transportation from the yard is provided by a wheel loader. From the storage tank the fuel is transported into a plate separator where fuel pieces exceeding 150 mm are sorted out. From the separator, the fuel is transported by means of a conveyer belt over which an electromagnetic separator of iron is placed. The covered belt follows into the boiler house. Inner Fuel Transport The supply includes the inner conveyer belt into the operation storage tank and the storage tank itself. Lifting up of the fuel from the storage tank is carried out by means of a hydraulic operated underpassable floor. The fuel is transported from the storage tank into the fuel chutes at the boiler by means of rake conveyers. Inner Ash Transport The inner transportation of solid residuals after the combustion is solved by means of screw feeders. Solid residuals after the combustion are created by siftings through the grate and by withdrawal from the area above the grate. The siftings under the grate is led out through a rotating feeder by chutes directly into a cooled screw. The ash discharge of each layer is implemented into a cooled screw, as well. All the slag is brought by means of these screws Page 5

7 and cooled chutes into a common cooled screw where it is being cooled down. The slag is subsequently led by means of a split-axle-type spiral conveyer through a grinder into the container. Equipment for Flue Gases Exhaust and Cleaning The flue gases from the boiler are led away by the smoke flue into the electrostatic fly ash precipitator being placed outside behind the boiler house wall. An exhaust fan with a frequency converter is placed behind the precipitator. The fly ash precipitator position can be seen in the attached picture. Page 6

8 Instrumentation and Control System (I&C) The I&C system solves the collection of all technological information on the boiler operation and the evaluation within the control system and further use of information for signalling, control, regulation and protective automatic functions and indication of all important values and states at displays for need of the operating personnel. Electrical Installation The entire cabling, power panels including the frequency converters, electrical protections, lightening etc. are designed and supplied within the electrical installation. Page 7

9 Scope of Activities Offered: Complete design documentation, construction documentation and supplier documentation of boiler + I&C + E Supply of boiler including accessories + I&C + E Assembly of boiler including accessories + I&C + E Supply of complete boiler house sets according to the Client s requirements Tests and commissioning including chemical cleaning and blowing Complex tests Test run Operation and maintenance instructions Operators training As built documentation Page 8

10 REFERENCE PROJECT BF45S-Type Steam Boiler K7 for Biomass Incineration Operator: Plzeňská teplárenská a. s. Doubravecká 2578/ Plzeň Czech Republic Contact person: Mr Zdeněk Dongres Technical Director, Tel.: Basic Technical Boiler Parameters: Parameter Value Unit Rated steam production 45 tph Maximum steam production 49 tph Rated superheated steam pressure 6,7 MPa Rated superheated steam temperature 490 ± 8 C Rated supply water temperature 145 C Efficiency at rated steam production 91 % Regulation range at keeping parameters % Fuel: Uncontaminated biomass: Residual mass of logging; Wood mass arising from the maintenance of public and private green areas (including tracks, water routes, electricity distribution lines and others), bio fuels having been produced of this residual mass (so called green chips and the like); Wood not being usable in another way, biofuels having been produced thereof, byproducts and residual products of its processing; Targeted grown energy plants and biofuels having been produced thereof; Targeted grown energy woods and biofuels having been produced thereof. Biomass will be supplied grinded into mm with max. dimensions of 150 mm and the following main parameters: r Heating value Q i r Water content W t MJ/kg % Page 9

11 Pellets EKOVER Parameter Unit Range Heating value MJ/kg Water W t r % Possible composition of particular pellets sorts: EKOVER T: pellets of triticale above-ground part, straw and spikes inclusive of corn; EKOVER S: granulated fuel of hay, cereal straw and oil cake straw; EKOVER O: granulated fuel of cereals and oil bearing plants. Standard: The boiler including accessories is designed, constructed, manufactured, equipped and approved in accordance with the Government Regulation 26/2003 according to harmonized standards, especially to CSN EN Guarantee Measurement Results: Boiler Efficiency: Boiler Efficiency Guaranteed Value Actual Measured Value Measured % Corrected % Unit Total Values of Measured Gas Pollutants: Pollutant Guaranteed Emission Limit Actual Measured Value Unit SO mg.nm -3 NO x mg.nm -3 CO mg.nm -3 Solid emissions (Solid particles) mg.m -3 TOC mg.nm -3 Page 10