1. Gas boiler advantages
1.1 As the ash content, sulfur content and nitrogen content in the gas are lower than coal, the combustion is sufficient, the amount of dust in the flue gas is very small, and the emissions easily meet the national standards for gas equipment, which can greatly reduce environmental pollution and environmental protection. Good performance.
1.2 Qinghai gas boiler has less pollution of flue gas, less corrosion of convection tube bundle, good heat transfer effect, strong heat radiation ability, low smoke exhaust temperature, and significantly improved thermal efficiency.
1.3 Gas-fired boilers do not require auxiliary equipment such as gas, slag remover, dust remover, grate, etc., saving investment in boiler equipment.
1.4 Gas-fired boilers use gas delivered by pipelines as the power source, and do not require gas storage. Good sanitary conditions can greatly reduce labor intensity, improve labor conditions, reduce operating costs, and save operating costs, space and labor.
1.5 In terms of boiler operation, regulation and reduction of heating costs.
1.5.1. The adaptability of the gas boiler heating load is strong, and the size of the fire can be flexibly adjusted according to the load (water temperature).
1.5.2. The system starts quickly and reduces various consumptions caused by preparatory work.
1.5.3. Due to the small amount of auxiliary equipment, the power consumption is lower than that of coal-fired boilers .
1.5.4. There are few magazines in the gas, the boiler will not corrode at high and low temperature heating surface, the boiler will run continuously for a long time, and there will be few failures.
1.5.5 The gas measurement is simple and accurate, which facilitates the adjustment of the gas supply.
1.6 In terms of reducing equipment maintenance, gas boiler combustion coefficient equipment is simple, so less equipment needs to be maintained, and the service life of heated pipe fittings is long. 1.7 The gas boiler is simple to operate and easy to realize automatic control.
2 Characteristics of coal-fired boilers and gas-fired boilers
Due to the different physical and chemical properties of coal and natural gas, there are large differences in characteristics between gas-fired boilers and coal-fired boilers.
2.1 Burning method
The coal-fired boiler adopts the stratified combustion method, and the coal is conveyed on the plane of the chain grate by the coal-feeding machine, and the combustion process is completed in the hearth. The gas-fired boiler uses chamber combustion. After the natural gas is mixed with air in the burner at a predetermined ratio in advance, it is sprayed into the furnace through a nozzle, which is burned in a torch.
2.2 Combustion products
Coal is mainly composed of c, H, s, 0, N and other elements, ash and moisture, but it is not a mechanical mixture of these components, but an extremely complex compound. After the combustion of coal, heat is emitted and SO2SO3 NOx is emitted from the flue gas into the atmosphere, polluting the environment and causing harm to human
The main component of natural gas is methane (CH.) Gas, which contains a small amount of non-hydrocarbon gases
Generally, it does not contain moisture and ash. After the combustion of natural gas, it mainly produces co2 and water, and emits a lot of heat. The harmful SO2, SO3 Nox and other emissions are much less than coal.
2.3 Ventilation method
Coal-fired boilers generally use negative pressure combustion. The combustion process is completed by the cooperation of blowers and induced draft fans. During the combustion of coal, a large amount of air is required, and due to the leakage of the furnace wall and flue, the excess air coefficient can be Up to 2.1 to 2.5.
The gas-fired boiler uses micro-positive pressure without the leakage of the furnace wall and the flue. The excess air coefficient at the flue outlet during operation can be 1.05-1.2.
2.4 Explosiveness of fuel
Coal-fired boilers are safe to burn and the furnace is unlikely to explode. However, within the limits of explosive concentration, gas boilers will explode when exposed to open flames, which is more dangerous.
2.5 Automatic boiler control
Because coal-fired boilers are limited by factors such as coal type, coal seam thickness, blast volume, induced air volume, air volume distribution, and grate speed, it is difficult to automatically adjust boiler operating parameters based on load.
Gas-fired boilers have fewer affected factors. Only the size of the burner can be adjusted according to the load, which is easy to achieve automatic control.
3 Basic requirements for technical transformation
3.1 Boiler reconstruction must be carried out in accordance with the " Steam Boiler Safety Technology Supervision Regulations" and "Hot Water Boiler Safety Technology Supervision Regulations" and relevant national technical regulations. The construction plan shall be submitted to the local technical supervision department for approval.
3.2 It is necessary to determine the value of the retrofitted boiler according to its useful life and technical status, and consider the expected life of the boiler. If the boiler has a long service life and severe corrosion, fouling, and overheating of the pressured components, there is no value for reconstruction.
3.3 Boiler furnace wall, flue, water supply, air supply and air induction system should be kept basically intact.
3.4 After the transformation, the original technical parameters of the boiler shall be kept unchanged (working pressure, temperature, etc.) or the load and efficiency of the original boiler shall be improved.
3.5 After the boiler is transformed, it shall meet the requirements of national environmental protection and various technical indicators, and be completely resolved.