Biomass Fired Boilers Fueled by EFB & Moving Floors

 Scope of Work

The scope of works of this tender shall comprise the design; engineering; fabrication; supply; site assembly, erection and installation; testing and commissioning of the described for the:

•  Biomass Boiler including necessary building,
•  Warehouse house for the shredded empty fruit bunch (SEFB) including moving floors.
•  Conveyor system for the transportation of SEFB to Boiler and removing dust and ash to ASH Storage
•  ASH Storage

Background

The Refinery currently utilize 70 tons per hour Steam Boilers with output at 42 bar (g) 4850C, using Natural Gas Fuel. It is now desired to incorporate two units of Biomass Boiler to supplement the Steam oilers usage, where the existing Natural Gas steam boiler shall be maintained and used during maintenance of the Biomass Boilers.

Technical Specification and Scope of Supply Biomass Boiler.

DESIGN BASIS

Vendor shall provide but not limited to the following:

A. Boiler and its Auxiliaries

1. Complete Bi-drum, D-Type boiler package with pressure parts comprising

• a. Steam drum with internals, water drum.
• b. Furnace water wall tubes
• c. Convection bank tubes
• d. Superheater

2. Non Pressure Parts

• a. Base frame
• b. Inner and outer casing
• c. Refractory and insulation
• d. Wind box
• e. Access doors and peep holes
• f. Boiler buck stay

3. Two numbers steam drum safety valves with silencers for each unit of boiler.

4. One number superheater safety valve with silencer for each unit of boiler.

5. Startup vent with silencer. Startup vent should have a manual isolation valve before the motorized valve.

6. Boiler Mountings and fittings. One absolute water level gauge with isolation valves and drain valve directly mounted on right hand side of steam drum and a remote level water indicator on left hand side of drum.

7. Integral steam and water piping of the boiler. All vents to be terminated at safe elevation and all drains to be terminated on a common header for further disposal into the waste water treatment plant along with the blow down.

8. Integral air and flue gas ducting.

9. Air Pre-heater and Economizer with inlet and outlet headers, outer casing and supports. Provision for installing a feedwater bypass line shall be made.

10. Free standing steel chimney – one chimney each for each boiler. The chimneys shall be provided with aviation lamps, lightning arrestor, sampling points, and a ladder to the top of the stack.

11. A CEMS unit (Continuous Emission Monitoring System) shall be installed to analyse and monitor the chimney flue gas emission, complying to the requirements of the DOE – Department of the Environment.

12. Forced Draft (FD) and Induced Draft (ID) fan driven by an electric motor directly coupled. The fans to be designed so that the impeller can be removed for maintenance without having to dismantle the ducting. The fans shall be designed for a total minimum discharge capacity of 25% higher than the theoretical air required at 5% excess air of rated MCR and head 20% higher than required at rated MCR.

13. The fan motor shall be driven by a variable frequency AC drive (VFD). The motor winding shall be of a design suitable for use with a VFD. Variable vane control damper with actuator in the inlet and outlet of the fan shall be provided. Fan shall be dynamically balanced. Flow measurement device shall be provided for measuring the air flow to the furnace. The fan design temperature shall be a minimum of 40°C.

14. Deaerator Boiler feed water station common for two boiler consisting of;

• a. Deaerator mounted on deaerated water tank with 30 minute storage capacity and suitable for maximum flow rate of 175 M³/Hr. shall be provided to obtain a temperature rise of feed water. The refinery is designed for 95% return of pure condensate at approximately 95°C. Make up water from the water treatment plant at ambient temperature will be used for condensate make-up. The deaerator should be designed to cater to both these inlet conditions and maintain an outlet temperature of 105°C of boiler feed water.
• b. The deaerator should be provided with
• i. Automatic deaerator pressure control valve with 2 isolating and 1
• bypass valve.
• ii. Automatic deaerator level control valve with 2 isolating valve and 1
• bypass valve.
• c. The storage tank with 30 minute storage capacity shall be provided with inlet connections from deaerator, chemical dosing arrangement, overflow leading to treated water storage tank in the water treatment plant, air vent etc. shall be supported on steel structure. Access ladder and platform around the tank shall be provided. The tank shall be complete with gauge glass level indicator assembly. The tank shall be supported on steel staging from ground floor at a height suitable for the required NPSH of the boiler feed water pumps.
• d. Condensate transfer pump from outlet of pure condensate storage tank to deaerator including piping and valves. 15. Boiler feed water station common for two boilers should be capable of supplying the boilers continuously at 120% of MCR and consisting of;
• a. 3 x 100% (2 duties + 1 standby) feed water pumps electrically driven with automatic recirculation system connected to deaerator. While arriving at the capacity of the pump, the requirement of the temperature and the de-superheating station should be taken into account.b. Complete feed water piping (including valves) from deaerator outlet to boiler feed water pumps to feed control station
• c. Feed control station consisting of 2 x 100% pneumatic control valves (one unit each to each boiler) with inlet and outlet isolation valves.
• d. Condensate transfer pump from outlet of pure condensate storage tank to deaerator including piping and valves.

15. Boiler feed water station common for two boilers should be capable of supplying the boilers continuously at 120% of MCR and consisting of;

• a. 3 x 100% (2 duties + 1 standby) feed water pumps electrically driven with automatic recirculation system connected to deaerator. While arriving at the capacity of the pump, the requirement of the temperature and the de-superheating station should be taken into account.
• b. Complete feed water piping (including valves) from deaerator outlet to boiler feed water pumps to feed control station
• c. Feed control station consisting of 2 x 100% pneumatic control valves (one unit each to each boiler) with inlet and outlet isolation valves.
• d. Back up pump function for Feed & deaerator system: Any tripping / overloaded/stop/ pressure / level dropped case of duty pump, the standby pump either from boiler-1 or 2 shall able to automatic start without failure (Objective: to maintain continuous boiler operation should discharge pressure drop or level low)

16. Chemical dosing system;

• a. LP dosing system with suitable pumps (1 duty + 1 standby) along with rubber lined tank with SS agitator and associated piping.
• b. HP dosing system with suitable pumps (1 duty + 1 standby) along with rubber lined tank with SS agitator and associated piping.
• c. Water piping for preparation of chemicals

17. Blow down system with CBD and IBD valves with isolation and bypass valves and blow down tank and piping. Blow down cooler to ensure temperature of the blow down water to the waste water treatment plant is at ambient temperature.

18. Manual operated main steam stop valve (MSSV) valve at outlet of boiler preceded by non-return valve.

19. The high pressure steam piping from boiler outlet to the high pressure steam distribution header (HP Header).

20. The high pressure steam piping from the HP header to the inlet of emergency stop valve of the steam turbine. Motorized or manual operated isolation valve with integral motorized / manual operated bypass valve before the emergency stop valve of the steam turbine shall be provided.

21. Flow nozzle for steam flow measurement at outlet of boiler to HP steam header.

22. Arrangement for steam blowing during testing and commissioning of the boiler will be done by the supplier, required piping, flanges, target plate, to be supplied by the vendor.

23. Piping supports for steam piping including the design and analysis of the supports.