Co-Operative Rural Power Plant (With Diagram) | Energy Management

In this article we will discuss about the cooperative rural power plant based on fluidised bed combustion system of biomass, with the help of a suitable diagram.

All the energy needs of a village can be met locally from the available biomass using the fluidised bed technology. A project on the design of a cooperative rural power plant based on fluidised bed combustion system of biomass was undertaken at Regional Engineering College, Kurukshetra.

The salient features of the project are described below:

i. Survey Data of Village ‘BIROHAR’ in District Kurukshetra:

ii. Biomass Availability:

Total biomass required for the proposed plant of 3MW_t capacity based on 35% overall efficiency and biomass heating value of 15 MJ/kg is 25t per day Therefore, it is required to collect the additional requirement from the surround­ing villages or by undertaking special fuel crop plantation.

Agricultural residues are seasonal depending upon the crop. However, some overlay and with properly managed storage areas, a fairly uniform feed supply can be ensured. The biomass can be stored in an enclosed area of 15m × 15m with a heap height of 6m. This is worked out on the basis of 60 day’s inventory and bulk density of biomass of 150 kg/m³. A shredding machine is required to keep the feed size of 6 cm.

The biomass, sized and dried is fed to the combustion chamber through belt conveyors and screw feeder 25 cm diameter × 16 m long driven by 1 kW motor. The feed control is automatically affected by regulating the speed of the motor. A 600 mm rotary valve is used to feed biomass to the combustor under pressure.

iii. Proposed Focal Village:

iv. Plant Specifications:

v. Component Design:

1. Distributor Plate:

Three compartments for differential velocities to ensure circulation of sand and biomass inside the furnace. The minimum velocity through sieve is 2m/s and velocities in the three chambers are 2.4m/s, 2.8m/s and 3.2m/s.

2. Dust Collection System:

A cyclone separator is provided after the heat recovery unit and before the stack to remove dust particles. The cyclone separator with 98% efficiency will be 1150 mm diameter and 2300 mm height.

3. Steam Tubes:

Ceramic tubes of silicon carbide with 2 fins per centre (disk type), 80 mm diameter and 1.6 mm thick 234 tubes of 1500 mm length will be required.

4. Steam Parameters:

Super-heated steam at 20 bars and 275°C. Flow rate- 2.7 t/hour

5. Automatic Control and Interlocking:

The aim of control system is to meet the variable load demand effectively.

The main requirements are:

(i) To maintain highest combustion efficiency,

(ii) To regulate air supply in fluidised bed,

(iii) To control fuel feed, and

(iv) To control steam flow rate.

The controlling parameter used is steam pressure which is used to control feed-water rate, fuel supply rate and air quantity Electrical system is used for transmitting signals to water control valve, fuel feed motor and blower damper.