At the straw
The basic criterion from comparing this alternative source of energy with the classically used energy system based on the combusting of fossil fuels is decreasing of greenhouse gases production. Whereas the burning of coal, petroleum and natural gas releases carbon dioxide into the atmosphere, which is one of the most significant „greenhouse” gases, the emission of carbon dioxide isn’t increased by the combusting of organic fuels, as practically the same amount the carbon dioxide released in the bur-ning is consumed from the atmosphere during the photosynthetic processes when the organic biomass is created. By the substitu-ting the burning of fossil fuels with the burning of biomass, the emission of carbon dioxide is eliminated.
Description and purpose
The VESKO-S boiler is independent with entirely welded box construction. The lower part of the boiler forms grate case, walls of combustion chamber are cooled by water. Grate is cooled by combustion air and it is controlled by hydraulic gear. Waste gases go trough first draft of conventional exchanger, then they continue into double draft separate water exchanger. Waste gases are sucked away From boiler through dust off system by flue exhauster and they are leaded into the chimney. Fuel (trusses) is supplied by fork lift truck into area under stacker. Then stacker gives trusses on the conveyor which is moving them into cutting device. Here are trusses hoisted into vertical chamber, separated by means of knife and pushed by piston via cooled tunnel on the boiler grate. The fuel way is blocked by gate (water cooled shutter) when piston moves back so that recombustion would not occur.
Boilers are designed for heating plants of a central heating supply and industrial plants.
They are produced in following sizes:
| Thermal output | 2,0 - 5,0 | MW |
| Operating over-pressure | 0,3 - 0,6 | MPa |
| Operating temperature | 90 - 110 | °С |
Environment
Waste gases exhausted from the boiler into the atmosphere comply with emission limits and they are in accordance with act about atmosphere protection No. 86/2002 Col.
Fuel
Grain straw, rape straw, triticale, flax about moisture max. Wr = 17%, calorific power min. = 13,9 MJ/kg, ash content max. A’ = 5,3%, in the Form square truss of sizes:
- width 1,2 m, height 0,7 to 1,2 m, length 2,2 to 2,5 m
- truss weight From 200 to 350 kg
Guaranty Fuel For reaching of the power.
Grain straw of the parameters:
- Moisture max. 15 %
- Calorific power min. 14,2 MJ/kg
- Ash content max. 5,3 %
| Parameters |
WARM WATER BOILERS |
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| Nominal output of boiler | МW | 2,0 | 3,0 | 4,0 | 5,0 |
| Maximum working over-pressure | МPа | 0,6 | |||
| Maximum temperature of output water | °С | 110 | |||
| Water quality according | to CSN 077401 | ||||
| Under-pressure in combustion chamber | Pа | 200 | |||
| Output temperature of wastes | °С | 150 | |||
| Efficiency of boiler | % | 87 | |||
| Fuel consumption in nominal output | kg/hod | 594 | 891 | 1 188 | 1 485 |
| Basic dimensions of boilers | |||||
| Height of boiler | mm | 4 400 | 4 800 | 4 800 | 5 400 |
| Length of boiler | mm | 6 300 | 6 500 | 7 000 | 7 300 |
| Width of boiler | mm | 2 200 | 2 200 | 2 200 | 2 200 |
| Dead weight (dry) | kg | 60 000 | 70 000 | 80 000 | 85 000 |
| Water volume | м³ | 18,5 | 19 | 21 | 23,5 |
| Service weight | kg | 78 500 | 89 000 | 101 000 | 108 500 |
| Notes: The producer reserved the right to change data in association with the development of the products. | |||||
Advantages of the conception
Fuel feeding. Stocking trusses by forklift truck into the columns under the crank stacker minimize necessary area for storage and handling with straw. Dividing of straw truss in the cutting device has a minimal energy demands and there is not necessary any other adjustment of the truss before entering the boiler (for example removing a rope), load of the knife is minimal there is no need to change it often.
Combustion chamber. Combustion chamber is completely cooled by heat transfer fluid, walls of the combustion chamber creates exchanger. Combustion chamber cooling minimizes inherent ash sintering.
Perfect automation of the boiler. Boiler runs in full-automatic operation, the combustion is optimised on the basis of under-pressure in the combustion area and through a surplus of oxygen in the combustion products. The fuel feed and the movement on the grate is regulated in accordance with the fuel’s characteristics. All measured quantities, interventions of the safety equipment and defects are transmitted to the dispatching system.
