Thermal and aerodynamic calculation of boiler unit DE - 6.5 - 14 GM

Contents

Contents

Task

Introduction

Calculation of volumes and enthalpy of combustion products

Boiler heat balance and fuel consumption calculation

Calculation of heat exchange in the furnace

Thermal calculation of convective bundle

Calculation of water economizer

Aerodynamic calculation

Selection of Smoke Pump

Literature

Introduction

The first steam boilers at the beginning of the XIX century. produced steam with a pressure of 0.5-0.6 MPa and had a capacity of hundreds of kilograms per hour. Currently, boilers are used for steam production, generating steam with a pressure of up to 25 MPa (and even up to 31 MPa) and a temperature of up to 570 ° C and a capacity of up to 4000 t/h.

The intensive development of boiler equipment was caused by the growth of industrial production and the concentration of electricity generation mainly at steam turbine power plants. Created during the years of Soviet power, the boiler industry, which has boiler plants, specialized research institutes and other organizations, provides the production of modern boilers necessary for the country and for their export abroad.

A modern boiler plant is a complex structure, consisting of a large number of different equipment and building structures, connected as a whole by a general steam production scheme.

The process diagram of the boiler plant is modified depending on its purpose, capacity, steam parameters, type of fuel, method of its combustion and local conditions.

In boiler plants using liquid and gas fuels, there are no ash trapping devices, equipment for removing slag and ash, storage devices are significantly simplified (with gas fuel, they fall away), transportation and preparation of fuel for combustion.

At industrial enterprises there are boiler plants that complement technological units, in which steam is generated due to the heat of off-gases or heat transmitted to their cooled elements. In recent years, power plants have been used, in which the boiler is an integral part of the technological unit.

The boiler plant equipment is conditionally divided into the main (boiler itself) and auxiliary. Auxiliary are equipment and devices for supplying fuel, feedwater and air, for removing combustion products, cleaning flue gases, removing ash and slag, steam pipelines, water pipelines, etc.

Boiler consists of furnace chamber and gas ducts, heating surfaces under internal pressure of working medium (water, steam-water mixture, steam): economizer, evaporation elements, superheater. Evaporation surfaces - screens and feston are included in drum and together with lowering pipes connecting drum with lower manifolds of screens form circulation circuit. The heating surfaces under pressure are combined by a drum in which steam and water are separated. Steam overheating is performed in the superheater. The air is heated in the air heater.

Fuel together with air is supplied through burners to furnace chamber where it is burned by flaring method. On the walls of the furnace chamber there are screens consisting of a large number of vertical pipes, and at the outlet of the furnace - a feston, which form evaporative heating surfaces that receive part of the heat of combustion products. The natural circulation of water and steam-water mixture in the system is organized due to the difference in mass of the water column in the lowering pipes and the steam-water mixture in the lifting pipes of the screens and the feston.

After the furnace chamber, combustion products pass through a superheater, in which steam is overheated to the required temperature, after which it is sent to consumers. After superheater, combustion products pass through economizer, in which feed water is heated, and air heater, in which air is heated, which goes to fuel combustion. The cooled combustion products are removed from the boiler.

There are various boiler designs. For example, forced circulation of water and steam-water mixture is used in the boiler evaporation system using special pumps. Evaporation surfaces of boilers are sometimes made in the form of heating pipe surfaces located behind the furnace chamber. In some cases, part of the surface of the superheater is located in the furnace, and the economizer and air heater are made in several stages, etc.

The modern boiler is equipped with automation systems that ensure the reliability and safety of its operation, rational use of fuel, maintaining the required productivity and steam parameters, increasing the productivity of personnel and improving their working conditions and protecting the environment from harmful emissions.

Literature

Esterkin R. I. "Boiler plants. Course and Degree Design "

M., Energoatomizdat, 1989

Rodatis K.F. "Handbook on low-capacity boiler plants"

M., Energoatomizdat, 1989

"Thermal calculation of boiler units. Normative Method "

L., "Energy," 1977

"Aerodynamic calculation of boiler plants. Normative Method "

L., "Energy," 1977

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