Gas supply of the boiler house of the City Children's Hospital
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3.6 Operation of gas-using units.
When starting a gas-using unit, gas-burner devices and automation are adjusted. The scope of commissioning works includes blowing of gas pipelines, and during the initial start-up - also drying of the unit. Primary start-up of gas fired boilers is performed after testing of gas pipelines and equipment. At the same time, there should be a launch certificate issued by the inspection, and also maintenance personnel should be prepared accordingly. Before start-up, the boiler house shall be checked for compliance with the specifications, quality of installation works and their compliance with the design. The first stage of operation is the start-up of the local gas control plant and the blowdown of gas pipelines to the burner. During GRU start-up regulator and safety valves are adjusted. After completion of blowing and tightness check of connections, ignition of gas burners is started.
When setting up the automation of the boiler or other installation, the quality of work of individual devices and elements is checked, possible malfunctions are eliminated and the automation with the required indicators is achieved. First, they set up safety automation, and then regulation automation. Adjustment of gas burners is carried out to identify the optimal mode in which burners provide rated capacity of the unit with the best heat engineering parameters. During adjustment, burners with optimal excess air and minimal chemical incomplete combustion are achieved. Burners are controlled to ensure stable gas combustion in the required range of the unit capacity. Results of adjustment, recommended modes and obtained heat engineering parameters of the unit are recorded in a special report.
In order to avoid fires, explosions and poisonings when operating on gas fuel, safety rules should be observed. First of all, it is necessary to prevent the formation of explosive mixtures in rooms, gas ducts and smoke channels. For this purpose, the following are systematically monitored: density of gas pipelines and gas valves; condition of chimneys and ventilation units; serviceability of all shut-off and safety devices.
The development of the gas industry is one of the most important sectors of the economy and is essential in creating the material and technical base of the country, and therefore the government pays great attention to this industry. Our country is the first in the world in terms of explored reserves of natural gas and the second in terms of its production.
Natural gas, as a highly efficient energy source now widely used in all sectors of public production, has a direct impact on increasing industrial output, increasing productivity and reducing specific fuel costs.
The intensive production of natural gas and the need to deliver it to the consumer in the most economical way caused the rapid development of pipeline transport. Transportation of gas through pipelines is more convenient and cheaper than other vehicles, since it ensures the continuous (and practically without loss) supply of gases to the consumer directly from deposits or underground storage facilities. Over the years of Soviet power, over 200 thousand km were built. main and distribution gas pipelines. An important link in the country's general gas supply system is underground city gas pipelines, through which gas flows directly to residential buildings, utilities and industrial enterprises. The use of gas to illuminate cities in Russia began in the first half of the 19th century, however, industrial production of natural gas was not carried out, and associated oil gas was burned in flares.
The main task of gas farms is uninterrupted, reliable and economical gas supply to consumers, which requires a clear organization and management, scientifically sound planning of all performance indicators, identification and use of production reserves, and increased labor productivity.
The operation of the gas economy of cities and settlements is carried out by specialized organizations: offices, trusts and departments that provide the operation of underground gas pipelines, gas regulatory centers, gas equipment and residential buildings, utility enterprises. The operation of gas equipment of industrial enterprises, various organizations of institutions is the responsibility of the institutions themselves.
Workers and ITRs trained in the corresponding types of work and passing exams on the rules of safety and technical operation of gas farms are allowed to work in the gas industry. The re-examination of knowledge among workers is carried out daily, and engineering and technical workers have one race per three years. In addition, technical training, seminars, practical exercises and other forms of advanced training are regularly organized for gas workers.
Natural gas has a number of advantages over other fuels:
• The cost of natural gas production is significantly lower than other fuels.
• Labor productivity in its production is significantly higher than in coal and oil production.
• High heat of combustion, makes it advisable to transport gas through main pipelines over significant distances.
• Complete combustion is ensured and working conditions of maintenance personnel are facilitated.
• The absence of carbon monoxide in natural gases prevents the possibility of poisoning during gas leaks, which is especially important when supplying gas to utility and household consumers.
• Gas supply of cities and settlements significantly improves the state of their air basin.
Of course, there are shortcomings and negative properties of the explosion - and the fire hazard of natural gas, but all this does not reduce all the advantages of natural gas.
4. Boiler house internal gas supply
4.1 Gas Supply Diagram
Boiler house is supplied with gas from external medium-pressure gas pipeline. The gas supply diagram of the boiler house is shown in the drawings. The elements of the boiler house gas pipelines diagram are:
- general disconnecting device at gas pipeline inlet to boiler room
-thermo shut-off valve
-gas control unit
- gas flow measurement unit
- disconnectors on the branches of gas pipelines to the units
-fuel gas pipelines
-safety gas pipelines
The gas pipeline is introduced into the boiler house through the wall of the structure in the case, which is a section of pipe of larger diameter than the gas pipeline. The space between the case and the gas pipeline is sealed with a ground linen strand, and bitumen is poured from the ends. The case is designed to protect the gas pipeline from damage in case of minor deformations of the wall.
The disconnecting device at the inlet is designed to disconnect the boiler room in case of repair or accident, as well as when it is stopped for a long time.
The gas pipelines in the boiler room are open and attached to the walls (columns) using special metal brackets (supports) or suspensions with clamps. Connection of gas pipelines is made on welding. Split connections are provided in places of installation of shutoff valves, gas devices, pressure regulator and other devices.
Gas pipelines of the boiler house are provided with blowdown pipelines from the most remote sections of the gas pipeline, as well as from branches to each boiler. Purge gas pipelines ensure removal of air and gas-air mixture from gas pipelines before boiler start-up, and also displace gas with air during repair or long-term shutdown of the boiler house. The blowdown gas pipelines are provided with a disconnecting device, as well as a nozzle for gas sampling.
Purge gas pipelines are brought from buildings to a height of not less than 1 m above the roof cornice, at a place where safe conditions for gas dispersion are provided. A protective umbrella is mounted at its end to prevent atmospheric precipitation from entering the blowing gas pipeline.
Diameters of gas pipelines are determined by means of hydraulic calculation.
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