**3.3. Heat water boiler burning baled biomass**

The use of renewable energy sources is becoming more and more important, mainly due to continuously increasing prices of fossil fuels, resource depletion and global attempts to ach‐ ieve maximum feasible CO2 emission reduction. Researches in this area are very complex and in order to obtain reliable data it is necessary to carry out theoretical and experimental research of the process. For this purpose, a 1.5 MW industrial-scale hot water boiler was constructed and installed in the Agricultural Corporation Belgrade [20-22]. The boiler is based on waste baled soybean (and other types) of straw combustion, and it is used for heat‐ ing 1 ha (10000 m2 ) of greenhouses. Combustion in the boiler carried on so-called "cigarette" principle [11], where 0.7x1.2x2.0 m straw bales are used as fuel. The bales have parallelepip‐ ed shapes. In Figure 17, the scheme of the experimental hot water boiler is shown.

gas fan (19), leave the furnace through the stack (20). The view of the boiler house and heat

Development of the Technology for Combustion of Large Bales Using Local Biomass

http://dx.doi.org/10.5772/51095

69

Apart from the presence of the movable cross, used for secondary air supply, which can be considered as innovative, another new concept is the existence of a 100 m3 heat storage ves‐ sel - heat accumulator (Figure 18) with thermal insulation. It was introduced so that the whole facility could respond more appropriately to the heating needs of the greenhouses. Hot water produced in the boiler is stored in the heat storage vessel. At time when the ambi‐ ent temperature is relatively high and weather conditions are mild (sunny days, without wind etc.), the boiler produces much more heat i.e. hot water than necessary for greenhouse heating. The greenhouse systems use only the amount of hat water necessary for heating, and the heat surplus is stored inside the heat storage vessel. At time when outside tempera‐ tures are below zero, on windy and cloudy days, the heat produced by the boiler might not be sufficient, but the lacking heat is then supplied from the heat storage vessel. The boiler is

A cigar firing combustion system is expected to exhibit the following advantageous features: a) combustion of whole bales and whole energy crops; b) compact combustor design; c) short start up period, good load-following performance; d) profitable operation of smaller facilities (down to 1 MWth); e) division of combustion from the heat recovery system, usable not only for the provision of steam (for heat generation or CHP), but also as a hot gas gener‐ ator in industrial drying applications. Cigar burner combustion system promises a more competitive use of renewable for "green" heat and power generation as well as their use in

Possible disadvantages of cigar burner combustion system include: a) a need for a "smart" and sophisticated process control system; b) thermal cracks, thermal attacks on the metal

operated and controlled by a SCADA-based system, through a computer.

**Figure 18.** The boiler house, heat accumulator and cyclone type separator

various industrial applications.

combustion chamber.

accumulator is presented in Figure 18.

**Figure 17.** The scheme of the demonstrating hot water boiler with thermal power of 1.5 MW

Baled straw (Figure 17, position 1) is fed to the facility by cylinder type transporters (2,3). After entering the rectangle cross sectioned bale feeding channel (4) bales are carried by a motor driven VSD controlled conveyor (6) towards the furnace (7). The section of the chan‐ nel (4) nearest to the furnace is made of multiple steel sheets (5), with primary air flowing through space between the sheets, thus cooling the sheets and being preheated at the same time. The furnace is made of refractory material (chamotte) (8), and is completely insulated (9). Ash is removed from the furnace by a transporter (10).

Preheated primary air (13) is supplied around the bale, and a portion of it also from under the grate (12), which is water cooled. Secondary air (11) is supplied through the movable cross onto the bale forehead, similarly as in the experimental furnace. The cross also serves as bale support from the forehead, for shaking-off ash from the forehead and for bale posi‐ tioning inside the furnace.

Leaving the furnace chamber, the flue gases pass through a heat pipe to the first section of the gas to water heat exchanger (14), and then through a chamber with screen barrier type particle separator (15) to the second section of heat exchanger (16). After final particle re‐ moval in the multi-stage cyclone type separator (18) the flue gases, transported by the flue gas fan (19), leave the furnace through the stack (20). The view of the boiler house and heat accumulator is presented in Figure 18.

**3.3. Heat water boiler burning baled biomass**

ing 1 ha (10000 m2

68 Sustainable Energy - Recent Studies

The use of renewable energy sources is becoming more and more important, mainly due to continuously increasing prices of fossil fuels, resource depletion and global attempts to ach‐ ieve maximum feasible CO2 emission reduction. Researches in this area are very complex and in order to obtain reliable data it is necessary to carry out theoretical and experimental research of the process. For this purpose, a 1.5 MW industrial-scale hot water boiler was constructed and installed in the Agricultural Corporation Belgrade [20-22]. The boiler is based on waste baled soybean (and other types) of straw combustion, and it is used for heat‐

principle [11], where 0.7x1.2x2.0 m straw bales are used as fuel. The bales have parallelepip‐

Baled straw (Figure 17, position 1) is fed to the facility by cylinder type transporters (2,3). After entering the rectangle cross sectioned bale feeding channel (4) bales are carried by a motor driven VSD controlled conveyor (6) towards the furnace (7). The section of the chan‐ nel (4) nearest to the furnace is made of multiple steel sheets (5), with primary air flowing through space between the sheets, thus cooling the sheets and being preheated at the same time. The furnace is made of refractory material (chamotte) (8), and is completely insulated

Preheated primary air (13) is supplied around the bale, and a portion of it also from under the grate (12), which is water cooled. Secondary air (11) is supplied through the movable cross onto the bale forehead, similarly as in the experimental furnace. The cross also serves as bale support from the forehead, for shaking-off ash from the forehead and for bale posi‐

Leaving the furnace chamber, the flue gases pass through a heat pipe to the first section of the gas to water heat exchanger (14), and then through a chamber with screen barrier type particle separator (15) to the second section of heat exchanger (16). After final particle re‐ moval in the multi-stage cyclone type separator (18) the flue gases, transported by the flue

ed shapes. In Figure 17, the scheme of the experimental hot water boiler is shown.

**Figure 17.** The scheme of the demonstrating hot water boiler with thermal power of 1.5 MW

(9). Ash is removed from the furnace by a transporter (10).

tioning inside the furnace.

) of greenhouses. Combustion in the boiler carried on so-called "cigarette"

Apart from the presence of the movable cross, used for secondary air supply, which can be considered as innovative, another new concept is the existence of a 100 m3 heat storage ves‐ sel - heat accumulator (Figure 18) with thermal insulation. It was introduced so that the whole facility could respond more appropriately to the heating needs of the greenhouses. Hot water produced in the boiler is stored in the heat storage vessel. At time when the ambi‐ ent temperature is relatively high and weather conditions are mild (sunny days, without wind etc.), the boiler produces much more heat i.e. hot water than necessary for greenhouse heating. The greenhouse systems use only the amount of hat water necessary for heating, and the heat surplus is stored inside the heat storage vessel. At time when outside tempera‐ tures are below zero, on windy and cloudy days, the heat produced by the boiler might not be sufficient, but the lacking heat is then supplied from the heat storage vessel. The boiler is operated and controlled by a SCADA-based system, through a computer.

**Figure 18.** The boiler house, heat accumulator and cyclone type separator

A cigar firing combustion system is expected to exhibit the following advantageous features: a) combustion of whole bales and whole energy crops; b) compact combustor design; c) short start up period, good load-following performance; d) profitable operation of smaller facilities (down to 1 MWth); e) division of combustion from the heat recovery system, usable not only for the provision of steam (for heat generation or CHP), but also as a hot gas gener‐ ator in industrial drying applications. Cigar burner combustion system promises a more competitive use of renewable for "green" heat and power generation as well as their use in various industrial applications.

Possible disadvantages of cigar burner combustion system include: a) a need for a "smart" and sophisticated process control system; b) thermal cracks, thermal attacks on the metal combustion chamber.
