Boiler DE 16 - Coursework for boiler units

Contents

Option

Introduction

1. Boiler House Design Basics

1.1 Choice of capacity and type of boiler house

1.2 Selection of number and types of boilers

1.3 Boiler Room Layout

1.4 Boiler room thermal diagram with steam boilers

2 Heat calculation of boiler unit

2.1 General provisions

2.2 Summary of Design Characteristics

2.3 Determination of the amount of air required for combustion,

composition and quantity of flue gases and their enthalpy

2.4 Preparation of heat balance of boiler unit and determination of hourly fuel consumption

2.5 Thermal calculation in the furnace

2.6Heat calculation of convective superheater

3 Thermal balance check

3.1 Design calculation of economizer

3.2 Thermal Balance Check

Conclusion

Literature

Appendix A. Thermal diagram

Appendix B. Boiler room layout

Appendix B. Steam boiler

Introduction

A boiler plant is called a set of devices and mechanisms designed to produce water vapor or prepare hot water. Water steam is used to drive steam engines, for the needs of industry and agriculture and room heating. Hot water is intended for heating industrial, public and residential buildings, for the communal needs of the population.

By the type of coolant produced, plants with steam and water heating boilers are distinguished. By purpose, steam boiler units are divided into industrial, installed in production and heating boiler houses, which are installed in boiler houses of thermal electric stations. By type, steam boilers can be divided into vertical-cylindrical, vertical-water-tube with a developed evaporative heating surface and screen ones. The modern steam boiler plant is a complex structure. The main part of it is the steam boiler itself, in which water is converted into saturated steam. However, at present, the steam boiler itself is supplemented by a superheater, a water economizer and an air heater in order to increase the efficiency of the boiler plant. The superheater is designed to increase the temperature and enthalpy of the steam produced in the boiler. In water economizer heat of flue gases leaving boiler is used, for heating of water supplied to boiler, and in air heater - for heating of air supplied to its furnace. Water economizer or air heater or both are installed in combination. Actually, the boiler, superheater, water economizer, air heater, as well as the furnace connected in a single organic whole, together with the adjacent steam and water pipelines, gas and air pipelines, and valves form a boiler unit as a whole. Boiler unit has frame with stairs and scaffolding for maintenance and consists in coating. Metal surfaces of boiler unit elements contacting flue gases and water, steam or air serve to transfer heat from flue gases to water, steam and air and are called heating surfaces. The modern boiler unit is serviced by a number of auxiliary mechanisms and devices, which can be individual and group. Auxiliary mechanisms and devices include smoke and blast fans, feed and water treatment plants, dust preparation plants, fuel supply, ash collection and ash removal systems - when burning solid fuel, fuel oil - when burning liquid fuel, gas control station - when burning gaseous fuel. The smoke pumps are designed to remove flue gases from the boiler plant. Blast fans are installed in order to overcome the resistance of burners or fuel layer on the grid when air is supplied to the furnace, as well as the resistance of air heater. Thermal, hydrodynamic and aerodynamic processes in the boiler plant must be controlled and controlled. According to this, it is equipped with control devices, such as superheated steam temperature controller, shutoff control and safety devices, and instrumentation. At the same time, boiler plants carry out complex automation of regulation of all the main processes taking place in them. Boiler plants located in the same building or on a common site in conjunction with the entire complex of auxiliary mechanisms and devices are called a boiler room. In accordance with the purpose and type of heat carrier produced, there are energy, production, heating and production-heating boiler houses, as well as boiler houses with steam and water heating boilers.

Boiler House Design Basics

Choice of capacity and type of boiler room

The design of the boiler house begins by identifying the nature of the consumers and determining the amount of heat or steam required for them, as well as the type and parameters of the coolant. At the same time, production boiler houses usually generate steam for technological needs, heating and ventilation of production workshops; heating boiler houses prepare hot water for heating residential and public buildings, as well as for household needs; production and heating boiler houses generate steam and prepare hot water for all the above types of consumption.

The need for heat for heating, ventilation and hot water supply of residential public and industrial buildings is determined by the projects of local heating, ventilation and hot water supply systems. In the absence of such projects, the need for heat can be calculated according to enlarged indicators. The release of steam for the technological needs of industrial enterprises and hot water is determined by the technological projects of these enterprises.

When the type and parameters of the coolant, as well as the complete heat or steam release, are detected, it is possible to set the profile and capacity of the designed boiler room. If all heat is released in the form of hot water, a boiler house with heating boilers is designed, if in the form of steam and in the form of hot water, then depending on the quantitative ratio of steam and hot water, a steam boiler house with a plant for heating network water or a combined boiler house with heating and steam boilers can be designed.

1.3 Boiler House Layout

In the layout of the boiler house, the aim is to most rationally place the main and auxiliary equipment so that it is convenient to operate it and at the same time that the boiler house is made compact, with a minimum volume of building, easy to build.

The boiler rooms are located in separate rooms that meet the requirements of the Rules of State Gortekhnadzor, "Construction Norms and Rules," "Fire Safety Standards for the Construction Design of Industrial Enterprises and Populated Places" and "Sanitary Standards for the Design of Industrial Enterprises." Boiler rooms shall not be adjacent to residential buildings. It is also undesirable to adjoin boiler rooms to production rooms .

There are three types of boiler houses: closed, semi-open, open. In closed boiler rooms, all main and auxiliary equipment (usually excluding ash traps) are placed in closed rooms. In half-open type boilers, boiler units and some of the most responsible auxiliary equipment are placed in a closed room, and smoke pumps, blast fans, ash traps and deaerators, tanks, etc. - in the open air. In open boiler rooms, almost all equipment is placed outdoors, building only a very small room for the shelter of personnel serving the front of boilers, as well as pumps and control boards. Recommendations for selecting the type of boiler house are given in SNiP II9276.

Boiler plants are designed only with individual smoke pumps, blast fans and ash traps. Fuel supply, feed pumps, water softener, deaerators and other equipment, as well as a chimney, are usually designed common to the entire boiler room.

Each boiler unit is placed in a separate construction cell; auxiliary equipment of the waterfall path is placed in a construction cell in one of the ends of the boiler house, besides, the auxiliary equipment room may not be separated by a wall from the boiler plant room. In addition, auxiliary equipment is placed in front of the boiler front. A heat shield is installed here, and with boiler units without air heaters, blow fans are often installed; in some cases, feed and network pumps, water treatment plant, deaerators are placed in front of the boilers.

The boiler house equipment shall be placed so that its building can be made of prefabricated reinforced concrete structures of the nomenclature and standard sizes used in industrial construction.

The span of the boiler building can be taken equal to: 6, 9, 12, 18, 24 and 30 meters, the pitch of the columns is 6 and 12 meters. The height of the room from the level of the clean floor to the bottom of the supporting structures on the support should be taken at a span of 12 m from 3.6 to 6 m inclusive by a multiple of 0.6 m, from 6 to 10.8 inclusive - by a multiple of 1.2 m, at high altitudes - by a multiple of 1.8 m.

With a span of 18 and 24 m from 6 to 10.8 - a multiple of 1.2 m.

With a span of 30 m from 12.6 - a multiple of 1.8 m.

In addition, with a span of 18 m, heights of 4.8 and 5.4 m are allowed, and for a span of 24 m - 5.4 m. For the possibility of expanding the boiler room, one of the walls is left free from development.

The rooms in which the boilers are installed provide on each floor two exits to the outside, located on opposite sides of the boiler room. Exit doors shall be opened to the outside by pressing the hand. The distance from the front of the boilers or projecting parts of the furnaces to the opposite wall of the boiler house is taken to be at least 3 m, and in the case of installation of auxiliary equipment, the width of the free passages in front of the boilers is kept at less than 1.5 m. However, this equipment should not interfere with the maintenance of the boiler. The width of the remaining passages between the boilers and the walls shall be at least 1.3 m. The distance from the top elevation of the boiler or from the elevation of the top maintenance area of the boiler to the lower parts of the boiler room coating structures shall be at least 2 m. Stairs and platforms made of non-combustible materials are installed to service the boilers. Not less than 2 ladders with width not less than 600 mm with inclination angle to horizon not more than 500 are installed to platforms more than 5 m.

Sites intended for maintenance of valves, instrumentation, etc. are made with width of at least 800 mm, other sites with width of at least 600 mm.

The boiler house is equipped with proper ventilation and is provided with natural and artificial lighting, creating illumination within 550 lux. Emergency lighting is provided from an independent energy source. The boiler house has fire extinguishing equipment in accordance with the current fire safety rules.

1.4. Boiler room thermal diagram with steam boilers

Low pressure steam boilers are installed to cover pure steam loads or to provide a small amount of thermal energy in the form of hot water from heat sources designed to supply consumers with steam. An expanded thermal circuit with three steam boilers is shown in Figure 2.

Steam from boilers is supplied to ROD reduction and cooling units, where its pressure and temperature are reduced. Temperature is reduced due to evaporation of feed water supplied to RPA, which is sprayed due to pressure reduction from 1416 kgf/cm2 to 6 kgf/cm2.

The main part of the steam is released for production needs from boiler house steam pipelines, part of the reduced and cooled steam is used in steam-water heaters of network water, from where it is sent to a closed system of heat networks. Condensate from external consumers is collected into condensate tanks and pumped by condensate pumps to feed water deaerators. Condensate from steam-water heaters installed in the boiler room is supplied directly to the deaerators. In addition, there is a pipeline to allow it to drain into condensate tanks.

Each steam boiler is equipped with a feed centrifugal electric pump. For all three installed boilers, the same backup pump is installed. Water can also be supplied to steam boilers by two steam piston pumps.

Actual heads of heat carriers are determined based on working pressure of steam in boilers and calculations of hydraulic resistance of the system of pipelines, valves and heat exchangers.

Heat calculation of boiler unit

2.1 General provisions

The heat calculation of the boiler unit can have two purposes:

a) when designing a new boiler unit according to the specified parameters of its operation (steam performance, temperatures of superheated steam, feedwater, air heating, etc.), the values ​ ​ of all its heating surfaces are determined.

b) if there is a ready boiler unit, all heating surface values correspond to the specified parameters of its operation.

The first type of calculation is called design, the second - verification. Check calculation is performed in the exchange rate project.

Heat calculation of the boiler unit is carried out according to the methodology developed by the All-Union Heat Engineering Institute named after F.A. Dzerzhinsky and the Central Boiler Turbine Institute named after I.I. Polzunov VTI and TsKTI. The values of the boiler unit are calculated sequentially, starting from the furnace, with subsequent transition to convective heating surfaces. A number of auxiliary calculations are made in advance: a summary of the design characteristics of the boiler unit elements is made, the amount of air required for combustion, the amount of flue gases along the boiler unit gas ducts and their enthalpy are determined; heat balance of boiler unit is made.

Heat calculation of the boiler unit is performed according to the following sections:

Conclusion

As a result of the completed project, four natural gas boilers DE1624GM will be installed in the heating and production boiler house. The steam capacity and heat capacity of the boiler house fully meet the needs of production and auxiliary needs.

During this course project, heat loads were calculated, boiler room parameters were determined, combustion processes, heat balance of boiler units were calculated, gas flow per boiler was calculated, auxiliary equipment was selected.

Heat calculations of furnaces, boiler flues were also made, the economizer was constructively calculated (calculation of the tail surfaces of the boiler unit) and the thermal balance was checked.