Residential district heat supply project

Contents

Introduction

1 Characteristics of natural conditions, place of construction and heat consumers

2 Determination of estimated heat consumption for heating, ventilation and hot water supply

3 Selection of thermal load control method. Drawing Temperature Plots

4 Determination of design coolant flow rate

5 Selection of optimal direction of network route and its description

6 Drawing up the design diagram of the thermal network. Preliminary hydraulic calculation of main and branches

7 Check hydraulic calculation

8 Construction of piezometric graph

9 Description of heat supply source. Selection of mains and makeup pumps

10 Calculation of heat network pipelines for compensation of temperature elongations. Selection of compensators

11 Selection of type of movable and fixed supports. Calculation of loads on fixed supports

12 Construction structures of heating networks

13 Construction of longitudinal profile of heat networks

14 Calculation of heat insulation layer thickness of heat networks pipelines. Determination of heat losses in heat networks

Conclusion

List of sources used

Introduction

The main tasks of district heating are to improve the provision of heat to industry and housing, save heat, increase heat sources and heat networks, improve circuits, improve the reliability of heat networks, improve the environmental situation in cities, etc.

District heating systems are characterized by a combination of three main links: heat sources, heat networks and local heat supply systems.

When choosing heat load coating sources, it is recommended to provide consumers with centralized heat supply from the CHP or from city (district) boiler houses.

The transportation of thermal energy from the CHP or boiler houses to consumers, i.e. to residential buildings, public and administrative buildings, is carried out through special pipelines called heat main networks. They were one of the most labour-intensive and expensive elements of the heat supply system. The heating line is a folded structure consisting of interconnected pipes, thermal insulation, compensators of linear temperature extensions, movable and fixed supports, shutoff and control valves, construction structures, chambers and wells, drainage devices, etc.

The main tasks in designing the district heating system are:

- determination of heat loads for heating, ventilation and hot water supply;

- determination of diameters of main pipelines and calculation of pressure losses in them;

- calculation of pipes for compensation of temperature extensions;

- determination of annual heat losses by heat networks;

- selection of the most economical method of heating line laying.

1 Characterization of natural conditions, construction site and heat consumption

The thermal highway is designed for the residential area of ​ ​ the city of Ufa at the estimated heating temperatures of the heating period for heating 35 ° C and for ventilation 20 ° C and wind speed in January 5.5 m/s. This district includes four microdistricts, in each of which there are residential and administrative buildings, hospitals, kindergartens and shops. So, for example, in residential microdistrict I there are four 9-story, two 5-story, six 2-story residential buildings, a kindergarten and a 3-story store. In each 9-story building there are 215 residents, in the 5-story - 350 people, in the 2-story - 45 people, the kindergarten is designed for 80 people, the store - for 35 jobs.

The source of thermal energy is the city boiler house, located in the industrial zone. Heat carrier for heat energy transportation is water. The heat supply system is closed, the number of pipelines in the heat network is two: supply and reverse. Water temperature in the supply line is 140 ° С, in the reverse 70 ° С. The heat energy consumers are connected to the heat main according to an independent scheme through the central heat station.

9 Description of heat supply source. Selection of mains and makeup pumps

The source of heat supply in the residential district of Ufa is the city boiler house. Its thermal capacity is 23 MW. The boiler house has 3 boilers of the DKVR type 6.5-13 without a superheater. The main fuel for the production of thermal energy is natural gas supplied to the boiler house through the main gas pipeline through the FRG. The reserve fuel is fuel oil of grade M40, supplied by rail in tanks. Water for boiler supply is used from water supply networks.

The main purpose of the boiler house is to supply power to consumers in Ufa, namely: production and transfer of thermal energy to the main heat networks, generation of chemically purified water for making up the heat networks; control and maintenance of established heat supply modes, provision of established parameters and water quality .

The coolant is moved from the boiler room to the consumer by means of a circulation pump, and the heat network is made up by a make-up pump. The main operating parameters of the pumps are head and supply. The number of pumps installed in the boiler house is accepted at least two in 100% of the required capacity, each of which is connected in parallel. One of these pumps is standby.

Pumps are selected from GRUNDFOS catalogue. Pump of NK 100315.Electromotor 160 kW with adjustable speed corresponds to 110m head and 300 m3/h supply. The efficiency of the pump is 68.3%, the motor is 95.7%. Energy consumption 419110 kWh/year.

Make-up pump is selected from the same catalog: head 70 m and supply 11m3/h corresponds to TPE 50900/2 pump. 22 kW variable speed motor. The efficiency of the pump is 37.9%, the motor is 86.1%. Energy consumption 34815 kWh/year.

12 Construction structures of heating networks

When selecting construction structures of thermal networks, SNiP 41022003 Thermal networks are guided.

On overpasses and stand-alone supports at the crossings of railways, rivers, ravines and other sections difficult to service pipelines, passage bridges with a width of at least 0.6 m should be provided.

For the maintenance of valves and equipment located at a height of 2.5 m or more, stationary platforms 0.6 m wide with fences and stairs should be provided.

Stairs with an inclination angle of more than 75 ° or a height of more than 3 m shall have fences.

When laying heat networks in channels below the maximum level of ground water standing, associated drainage should be provided, and for external surfaces of building structures and embedded parts - hydraulic protection insulation.

If it is impossible to use associated drainage, adhesive waterproofing shall be provided at a height exceeding the maximum groundwater level by 0.5 m, or other effective waterproofing. A tank with a capacity of not less than 30% of the maximum hour amount of drainage water shall be provided for water collection. For external surfaces of channels, tunnels, chambers and other structures, when laying heat networks outside the zone of the ground water level, coating insulation and adhesive waterproofing of the floors of these structures should be provided. The slope of the associated drainage pipes shall be accepted at least 0.003.

Removal of water from the associated drainage system shall be provided by gravity or pumping by pumps into the rain sewer, water bodies or ravines.

Frames, brackets and other steel structures for pipelines of heat networks shall be protected against corrosion.

13 Construction of longitudinal profile of heat networks

When constructing the profile, we are guided by GOST 21.60582 (1997) Networks thermal (thermal and mechanical) Working drawings. The network profiles are shown in the form of deployments along the axes of the network alignments.

Network profiles indicate:

- ground surface (design - solid thin line, natural - dashed);

- crossed roads, railway and tram tracks, cuvettes, as well as other underground and above-ground communications and structures affecting the laying of the designed networks, indicating their overall dimensions, elevations and, if necessary, coordinates or references;

- channels, tunnels, chambers, niches of U-shaped compensators, racks, separate supports, ventilation shafts, pavilions and other structures and structures of networks - with simplified contour outlines of internal and external dimensions - with a continuous thin line;

- pipelines of channel-less gasket - contour outlines of external dimensions with a continuous thin line indicating axes of pipes;

- fixed supports - with a schematic graphic image.

Pipelines in channels, tunnels, chambers and niches are not depicted.

On the profiles of the above-ground laying of networks, the pipelines of each tier are depicted as one solid main line. We place a table under the network profiles. We mark the networks at characteristic points, at intersections with roads and railways, tram tracks, engineering communications and structures that affect the laying of designed networks.

The elevation and length values of the mesh sections are indicated in meters with two decimal places, and the slope values ​ ​ are indicated in percentage or ppm.

15 Automation and control

Heat networks should include:

a) automatic regulators, shock devices and interlocks providing:

- the given water pressure in the supply or return pipelines of water heating networks with maintaining in the supply pipeline the constant pressure "after itself" and in the reverse - "to itself" (overpressure regulator);

- division (dissection) of the water network into hydraulically independent zones when the water pressure exceeds the permissible one;

- actuation of make-up devices in cutting units to maintain static water pressure in the disconnected zone at the specified level;

b) selection devices with the necessary shutoff valves for measurement:

- water temperatures in supply (selectively) and return pipelines in front of sectional gate valves and, as a rule, in the return pipeline of branches Dy 300 mm in front of the gate valve in the direction of water;

- water pressure in supply and return pipelines before and after sectional gate valves and control devices, and, as a rule, in supply and return pipelines of branches Dy 300 mm in front of the gate valve;

- water flow rate in supply and return pipelines of branches Dy400 mm;

- steam pressure in branch pipelines upstream the gate valve;

c) protection of equipment of heat networks and systems of thermal use of consumers against unacceptable pressure changes during shutdown of network or pumping pumps, closing (opening) of automatic regulators, shut-off valves.

Heat chambers shall be capable of measuring coolant temperature and pressure in pipelines.

18 Technical and economic calculation of heat supply system.

We will determine the most economical option for the construction of a heating line by comparing two types: laying heat pipelines in impassable channels and a channel-less gasket.

The creation of new enterprises, the expansion of existing ones, as well as the reconstruction and technical re-equipment of enterprises, require material labor and monetary resources. The totality of these costs is called investments.

Capital investments are used for construction and installation works, acquisition of technological equipment and other needs.

All construction and installation works can be performed in two ways:

- by contractor - under it works are carried out by specialized self-accounting construction organizations under contracts with the customer;

- by economic means - under it, work is carried out on its own.

The cost of construction is determined by the estimate. Estimate (estimated financial calculation) - a document describing the limit of permissible costs for the construction of the facility. The estimated cost can be divided into the following components: estimated cost of equipment; cost of construction and installation works; other expenses and income of the construction organization.

Estimates for the laying of the heating line in non-flow channels with insulation from mineral wool mat and a channel-less gasket with insulation from polyurethane foam are given in Tables 11 and 12, respectively.

The calculations will be based on the following data:

- estimated total hourly flow rate of network water Gph = 273.6 t/h;

- annual heat losses during laying in impassable channels Qtp year 1 = 6218.8 GJ/year;

- annual heat loss at channel-free laying Qtp year 2 = 6050 GJ/year;

- temperature plot of heat networks 14070 ° С;

- capital investments for laying of pipelines in impassable channels K1 = 29477043.81 rubles (Table 11);

- capital investments for channel-free gasket K2 = 26022294.78 rub.