Diploma on the topic: District thermal station with water heating boilers PTVM-120E

Contents

1. Introduction

2. Calculation of boiler room thermal diagram

3. Boiler description

4. Boiler Heat Calculation

4.1. Composition of design gaseous fuel

4.2. Boiler heat balance

4.3. Calculation of heat exchange in the furnace

5. Boiler room gas equipment

6. Description and calculation of chemical water treatment scheme

7. Water deaeration

8. Automation and monitoring of PTVM-120E operation

9. Calculation of 1 Gcal heat power generation cost

10. Safety of life

11. List of literature

Introduction

Heat loads, that is, consumers' hourly heat requirements, are the starting point for the boiler plant design. On the basis of heat loads, the boiler room thermal diagram is compiled and calculated and equipment is selected. Heat is released to consumers not only with various parameters, but also with the use of various heat carriers.

For heating, ventilation and hot water supply, as a rule, the coolant is water at various temperatures. Heat supply system of consumers connected to RTS heat networks is closed, double-tube. Superheated water coolant with a temperature schedule of 15070 ° C. In two-tube systems, the thermal network consists of two lines; feed and reverse. On the supply line, hot water is supplied from the station to the subscribers, on the return line, cooled water returns to the station. The predominant use of dual-tube systems in cities is due to the fact that these systems require less initial investments and are cheaper to operate. From both directions, the return network water is supplied through the mud tank to the suction header of the network pumps. Also, the suction line of heat pumps is supplied with water for its own needs and make-up water. Further, under the action of the network pumps, water enters the boilers. To prevent corrosion of boiler heating surfaces, return water temperature of at least 56 ° С is required. The water temperature is controlled at the inlet of the boilers by recirculating hot water. Part of heated water is withdrawn and supplied by recirculation pumps to return water pipeline behind network pumps. The bridge between the supply and return lines serves to control the flow rate and temperature of water in the heating system. The RTS heating capacity is controlled by changing the fuel supply. Coolant losses are compensated by chemically purified, deaerated water. The initial water is softened according to the scheme of two-stage sodium-cation. The chemically purified water is supplied to the vacuum deaerator, then it is supplied to the suction manifold of the mains pumps by underfill pumps. The boiler house thermal diagram is calculated in order to determine the water flow rate for individual units under the characteristic operating modes of the boiler house and to compile the total material balance of water. The calculation also determines the temperature of the various water streams.

The calculation results are the initial data for the equipment selection of the individual units of the thermal circuit and the main pipelines of the boiler house.

Increasing the number of people living in areas is a real problem. In densely notched areas, point development is used. In areas remote from the center, it is possible to build microdistricts with their connection to existing thermal stations. The main types of heat-generating sources are CHP of various capacities and purposes, RTS with medium and high-capacity water heating boilers, CTS of low power, as well as thermal stations with GTU.

When choosing heat generating plants to supply heat to residential areas and industrial enterprises, the most important argument is the lowest capital and operating costs. The capital costs for the construction and operation of a station with hot water boilers are 2-4 times less compared to stations with steam boilers. It is for this reason that small energy has recently played an important role.

Boiler Description

This manual provides information for the correct installation and operation of 58.2 (50) MW (Gcal/h) and 116.3 (* 0 *) MW (Gcal/h) hot water boilers (hereinafter referred to as boilers) operating on gaseous and liquid fuel .

The boiler type symbol for gaseous and liquid fuel consists of sequentially located:

- HF designations - hot water boiler;

- indices of GM fuel type - gaseous, liquid (fuel oil)

- values of boiler heating capacity in MW;

- values of nominal temperature of water at boiler outlet;

The designation accepted at OJSC DKM is given in parentheses

- P - peak;

- T - heating;

- B - hot water;

- M - fuel oil;

- boiler heating capacity values in Gcal/h.

- M - modernized

Example of a water heating boiler for gaseous and liquid fuels with a heating capacity of 58, * (50) MW (Gcal/h) with a rated outlet water temperature of 150 ° C: KV-GM - 58.2150 (PTVM - 50M ).

During operation of the boiler, except for this manual, shall

additionally use the following regulatory and technical

documents:

- "Rules for arrangement and safe operation of steam and hot water boilers," approved by the Gosgortekhnadzor of Russia

May 28, 1993.

- "Safety Rules for Gas Industry."

- "Guide to production of obmurovochny works" of A22910 I.

- "Gas burner of GGRU1000 recirculation devices"

6585.OPS passport and operating manual.

- "Instruction on technical diagnostics and expert

examination "A27750 I.

- "The instruction for repair of elements of boilers in the course of installation and operation with P <25 kgfs/cm2" A9570 .

- "Instructions for installation of thermal equipment in

part of small and medium-capacity boilers "Giprotehmontazh, 1993.

Technical description.

Water heating stationary boilers are designed for production

hot water with pressure up to *, 35 (13.5) MPa (kgf/cm2) and nominal temperature * 50 ° С used in heating, ventilation and hot water supply systems for industrial and domestic purposes, as well as for technological purposes .

2.4. Instrumentation, automatic control equipment, thermal protection and remote control are supplied by the component organization to the consumer according to its custom specifications.

2.5. Marking.

2.5.1. The hot water boiler shall have a plate as per GOST 129 * 167

indicating:

manufacturer;

designation of the boiler in accordance with this manual;

heating capacity in MW (Gcal/h);

operating pressure in MPa (kgf/cm2);

product serial number;

years of manufacture ;

rated outlet water temperature.

2.5.2. Marking on cargo places (box, package, bundle) meets the requirements of GOST 1419 * 96 .

2.5.3. Boiler elements operating under pressure are marked in accordance with the Rules of the State Gortekhnadzor of the Russian Federation. The locations of the markings are shown in the annex to this manual .

2.6. Packaging.

2.6.1. The boiler components are sent to the consumer in the following package :

small parts and assemblies, flanges, fasteners of all types and sizes, nozzles, support elements, as well as fittings and electrical appliances - in boxes, containers or boxes of welded structure;

screens, sections of the convective part, columns and beams of the frame, platforms, stairs, box, bunkers and other large-sized products - in packages, bundles or without packaging ;

bent pipes of similar configuration, straight pipes and rolled steel with a length of more than one meter - in bundles.

2.6.2. The boiler elements are packed according to the manufacturer's drawings.

2.6.3. Boiler elements are subjected to preservation by paint materials and lubricants before packing to protect them from atmospheric corrosion during transportation and storage. Preservation period is 12 months from the day of boiler shipment.

2.6.4. Cast iron parts, pipes and rolled stock sent to the consumer are not subject to preservation.

2.6.5. When packing parts, a packing sheet is inserted into the box

specifying the type and number of parts .

Water treatment plant

Management of the water regime and water treatment have become important in ensuring reliable and cost-effective operation of thermal plants and networks. Therefore, for the organization of water preparation, a complex and developed economy was created, which includes a complex of mechanical filtration of the source water - desalination of water at an electrodialysis plant - alkalization of diluate softening of water on counter-current sodium cationite filtrates - vacuum deaeration of chemically purified water - correction treatment of heating system make-up water.

Softening, deaeration of water are the main methods of combating scale formation and internal corrosion of pipelines and heat exchange equipment of the heat supply system.

At the station, to intensify and increase the efficiency of technological processes on the basis of scientific and technological progress, the means of complex automation of technological processes (boilers, auxiliary equipment: DU and STP) were widely used.

Deaeration unit

Description of the deaeration unit.

To protect the boiler heating surfaces, pipelines of the heat exchange equipment from corrosion, corrosive gases (dissolved oxygen and free carbon dioxide) are removed from the make-up water by degassing it. Corrosive gases enter the source water as a result of prolonged contact with the atmosphere. Removal of dissolved gases is a prerequisite for reliable and economical operation of boiler plants.

The design provides for one deaeration vacuum plant with a capacity of 50 m3/h (DV50) with two columns with a capacity of 25 m3/h each installed on a battery tank with an automated process control system.

Chemically purified water is supplied to the deaerator columns through the control valve, which has passed through the evaporator cooler and is heated on the heat exchanger of the 2nd stage up to 80 0С.

Deaerated water is discharged to make-up pumps from tank center.

Evaporation from the unit is removed through the evaporation cooler, where it is almost completely condensed, and not condensed steam-gas mixture is removed by ejectors into the BG separator and further into the atmosphere.

Condensate from the evaporator coolers is discharged to the service water tank.

APCS provides the following functions:

automatic protection of equipment when parameters fall outside the limits of the norm;

maintaining the level in the battery tank;

maintaining the temperature of the chemically purified water after the II stage heat exchanger;

maintaining a predetermined vacuum in the deaeration unit;

maintaining a certain temperature in the bacegas separator;

maintaining a certain level in the tank gas separator and in the service water tank;

transfer of water from the tank-gas separator to the service water tank;

pumping water from the service water tank to the deaerator column;

maintaining pressure on the "comb" of the coolant for technological needs;

determination of dissolved oxygen content in make-up water after make-up pumps using a stationary device - an oxygen meter;

information support of operators, based on design algorithms of equipment operation modes and displaying both the current state and helping to act in extreme situations.

Design of the vacuum deaerator DV50.

On the storage tank there is a jet column. The jet column is an apparatus in which water is distributed by means of hole trays into jets flowing from top to bottom in series in the form of several stages.

Softened water superheated in heaters of II stage above saturation temperature corresponding to pressure in deaerator is supplied through connector (1) to open chamber (2). In the chamber, superheated water boils and a significant amount of steam-gas mixture is formed. The water then overflows through the spillway threshold 3 and enters the first tray 4. In this tray there is a throat 5 for the vapour passage. The water is then cascaded through four more trays 6, 7, 8, 9 and drained into the storage tank. As the water moves through the height of the column, an additional removal of the vapor-gas mixture takes place, which is withdrawn through the necks of the trays 7, 9, the gaps between the body of the apparatus and the trays 6, 8 and is removed from the top of the column through the pipe 10 by water jet ejectors.

The formed steam is supplied towards the jet flow of water. Countercurrent flow in the deaerator is a positive element of this scheme.

Commissioning works.

The purpose of setting up a vacuum deaeration plant is to establish an optimal temperature vacuum mode, in which the content of aggressive gases in make-up water is within the limits of the norm, the minimum amount of evaporation is achieved, which ensures the reliability and cost-effectiveness of the boiler plant equipment and heat networks.

Sequence of DM adjustment operations with ACS:

maintaining constant level within specified limits at different values of source water pressure and makeup flow rate;

maintaining constant cold water temperature after the heat exchanger of the II stage at various values ​ ​ of the coolant temperature, pressure after the valve on the auxiliary "comb," makeup costs;

maintaining vacuum in accordance with the schedule of temperature vacuum dependence;

maintaining the level in the bacegas separator within certain limits;

transfer of water from the tank-gas separator to the service water tank when the specified temperature is exceeded.

During adjustment, the conditions required for normal deaeration were determined:

level in the deaerator tank - 1.6 m ± 0.1 m;

temperature of water supplied to the columns - 75 ± 5 OS;

water temperature in the bacegas separator is not more than 40 OS;

water level in the bacegas separator;

vacuum on columns corresponds to the diagram of temperature vacuum dependence;

the supply HOVE in a column has to be uniform, without sharp fluctuations both on an expense, and on temperature.

If the temperature vacuum mode, i.e. the ratio of the vacuum on the columns and the temperature of the cold water in the deaerator (see Appendix 2.8.4 "Table of the boiling point versus vacuum pressure") is observed, as well as the stable hydraulic load on the deaerator, the oxygen content was - 020 μg/dm3, free carbon dioxide - 0.

The results of adjustment tests DV50: for loads, temperature, pressure in the deaerator, as well as oxygen and carbon dioxide content in the deaeration plant are presented in Table 2.3 "Summary data table of controlled during adjustment of the deaeration plant DV50."

Water quality standards for heating system makeup

PTE, 2003; GOST 287482; OST 108030.4781.

Free carbon dioxide content - absence

pH value - 8.3 - 9.5

Dissolved oxygen content, μg/dm3, not more than - 50

Amount of suspended substances, mg/dm3, not more than - 5

Oil products content, mg/dm3, not more than - 1

Total stiffness, μgeq/dm3, not more than - 30

Automation and monitoring of PTVM-120E operation

The general tasks of monitoring and controlling the operation of the boiler unit and the plant are to ensure fuel combustion efficiency, rational use of electricity for its own needs; safety of operation of both the unit itself and auxiliary equipment.

The boiler personnel shall always have an idea of its operating mode, as can be seen from the readings of the instrumentation to be provided with the boiler unit.

When selecting the number of devices and their placement, they are guided by the rules of Gosgortekhnadzor for boiler units, gas supervision and SNiP II3576 "Boiler plants." The general position when choosing the place of installation of devices is the convenience of servicing the unit with a minimum number of people at low capital and operational costs for devices .

Modern control of boilers at thermal stations is carried out using automated process control systems (APCS) based on microprocessor equipment and controllers.

The ACS developed in this diploma project performs the following functions:

- adjustment of parameters characterizing the process;

- protection of equipment from damage due to violations during its operation;

- interlock, which provides automatic switching on and off of equipment of auxiliary mechanisms and controls with a certain sequence required by the technological process.

I&C boiler room has two levels, upper and lower.

The upper control level of the system has the following tasks:

- display of information on process status on monitor screens;

- transmission of boiler valves remote control commands via the network according to the operator's instructions;

- light and sound signalling about approach of process parameters to emergency values (warning) and when they reach emergency values;

- storage and processing of reports, archives, schedules of technological parameters change.

The lower level of boiler control is assigned the tasks of direct control of boiler valves:

- combustion process control;

- output of control actions on valves;

- reception and processing of equipment status information;

- reception and processing of information on process parameters;

- provision of boiler safety automation;

- transfer of all information about the boiler over the network to the upper level;

- reception of operator commands via the network from the upper level (start-up and shutdown of the boiler, start-up and shutdown of burners, valves control).

The heat load of the boiler is controlled by turning on and off the remote burners.

ECS can operate in two modes:

-regulation of gas pressure without oxygen correction;

-with oxygen correction.

In the mode without oxygen correction, when switching to automatic control, the gas pressure is set according to the mode map, regardless of its value in the previous manual mode. When the pair of remote burners is switched on/off, the gas pressure takes a new value. When one burner is on/off, the pressure value will correspond to the average between adjacent burner pairs. The duration of the pressure change transient does not exceed a few seconds.

The temperature change results in a corresponding change in the gas pressure (a decrease in the temperature of the blow air causes an increase in the gas pressure before the burners).

In the mode with correction by oxygen content in outgoing gases,

combustion process optimization controller corrects the gas pressure upstream the boiler according to KGA8S gas analyzer readings. The unified current signals 420 mA proportional to the content of O2, CO and NOX from the gas analyzer are supplied to the controller, where they are compared with the specified values and the required value of gas pressure downstream the damper of the DPE is calculated. At the output of the controller, a control signal is generated for the MEO 40/250.25 U actuator, the shaft of which is connected through a system of rods and levers to the PRZ control flap, which changes the gas supply to the burners of the boiler. The adjustment of the gas pressure downstream the RPP according to the values obtained from the gas analyzer is carried out with a 10 minute interval necessary to change the composition of the exhaust gases after the gas pressure correction pulse. The value of O2 is maintained with an accuracy of 2 - 3% of the value of the boiler specified in the mode map. In case of emergence in the leaving SO gases over 100 rrt adjustment on O2 stops and at the outputs of the controller the pulse signal covering the PRZ gate is developed. The reduction of gas pressure to minimize CO emissions begins. Once the JI has returned to normal, the O2 adjustment will begin again. If during the correction the gas pressure to the boiler received from the pressure sensor starts to differ from the value of gas pressure in the mode map by more than 10%, then the optimization regulator will automatically switch off and only the gas pressure regulator to the boiler will remain in operation according to the mode map. In this case, the operator receives the message "Adjustment according to the CGA readings is not possible" and an audio signal.

The control time is 710 seconds. At a possible gas pressure of 0.4, the control is carried out with an accuracy of 0.001. Change of blast air temperature is performed with discreteness of 0.10С (as per mode map 50С) and also leads to new steady-state values of gas pressure. Dynamic properties of the gas pressure control circuit are selected taking into account all technological features of combustion and capabilities of the actuator.

Boiler ignition is performed only in manual mode (with the control system disconnected). It is possible to switch the boiler to automatic operation only after switching on four decay burners. After ignition, ECS is activated and gas pressure is set in accordance with the mode map.

The following indicators are included in the full mode map:

- boiler heating capacity;

- number of burners on;

- numbers of burners on;

- gas pressure downstream the damper;

- a gas consumption (at 1r - 20 °C and Rb = 760 mm rt. article);

- water flow through the boiler;

- degree of water heating in the boiler;

- hydraulic resistance of the boiler;

- vacuum in boiler furnace;

- temperature of air going for burning;

- temperature of combustion products downstream the boiler;

- content in combustion products: carbon dioxide, oxygen;

- excess air ratio downstream the boiler;

- efficiency of the boiler;

- nominal fuel consumption for generation of one Gcal of thermal energy; air pressure at operating burners.

Calculation of production cost 1 Gcal

The cost of production is the valuation of natural resources, raw materials, fuel, energy, fixed assets, labor resources used in the production process, as well as other costs for its production and sale.

The cost of energy products and the costs of their production are part of the main indicators of the activities of energy enterprises. It depends on operating costs, which, in turn, are determined by the cost of constructing a heat supply source, depends on the productivity, correct selection and technical perfection of auxiliary devices and mechanisms, the degree of automation and mechanization of production processes, the cost of basic and auxiliary equipment, the type and cost of buildings and structures.

The cost of thermal energy is defined as the sum of all costs attributable to the volume of thermal energy production.