Pipes

Starting the boiler from a cold state. Ex.r.

The purpose of launch operations of a steam power boiler of a non-block TPP is to achieve the nominal steam parameters (pressure and temperature of live steam, as well as its quality) and such a minimum steam output at which the boiler can work stably for a general station steam collector.

Minimum steam output of the boiler depends on its initial thermal state, on the operating parameters of the boiler, its power, as well as on the degree of automation and the start-up technology used.

Feature of starting the boiler of a non-block thermal power plant is that the starting operations on it are carried out independently of the operations performed on the turbines. With a block layout of the equipment, the operations for raising the parameters on the boiler are associated with heating the live steam pipelines up to the turbogenerator, and the required steam parameters depend on the thermal state of the turbine. Currently, the blocks are launched on the "sliding parameters" of the steam.

Start-up operations on the boiler begin from the moment the DIS command is given to start the boiler and are considered completed when the nominal steam parameters and the minimum steam production are reached.

The start mode must meet the following requirements:

1. Reliable flow of internal boiler processes necessary for uniform heating of all elements of the boiler must be ensured.

2. The heating rate of the boiler elements must not exceed the values determined by the allowable thermal stresses in these elements.

3. Heat losses should be as low as possible.

4. The safety of personnel and equipment must be ensured.

Let us consider in more detail the issue of thermal stresses of the metal of the boiler elements.

In stationary thermal modes of operation of the boiler, the temperature difference on the walls of the boiler elements is small, so the temperature stresses are minimal. In non-stationary modes (starts, stops, load changes), the wall temperature differences increase significantly, which also leads to an increase in thermal stresses. In general, these stresses can be defined as

σ t = [β E/(1 – μ)] Δt K,

β is the coefficient of linear expansion of the material;

E is the modulus of elasticity of the material;

μ is Poisson's ratio;

Δt is the temperature difference between the inner and outer walls;

K is the coefficient characterizing the heating mode of the element:

K = 1/3 for stationary heat transfer modes;

K = 1/2 for start modes;

· K = 1 for thermal shocks.

In real conditions, thermal stresses cannot be determined. This is due to a number of reasons, for example, with the presence of deposits on the inner surface of the pipes and their slagging from the outside, with the uneven temperature field of the working fluid and gas flow, etc. In this case, the so-called criteria for safe operation, which are:

Permissible temperature differences in the critical elements of the boiler;

Permissible warm-up (cooling-down) rates;

Permissible temperature limits.

When operating boilers, one should be guided by the requirements of PTE, PPB, PTB, the rules of Gosgortekhnadzor, the requirements of factory and standard instructions, local job and production instructions for the maintenance and operation of the main and auxiliary equipment. The values of the specified criteria for safe operation are also regulated by these RD.

Start-up operations, in addition, are regulated by the "Standard Instructions for Starting from Different Thermal States and Shutdown of a Steam Boiler of a TPP with Cross-Links", 1995.

According to this instruction, depending on the initial thermal state of the boiler, the following types of starts are distinguished:

From a cold state (there is no pressure in the steam-water path, the boiler and steam pipelines are completely cooled down, corresponds to the shutdown of the boiler for a period of more than 2 days);

From the uncooled state (in the steam-water path, the overpressure is not more than 13 atm, corresponds to the shutdown of the boiler for 10 or more hours);

From the hot state (overpressure in the steam-water path is more than 13 atm).

It should be noted that the boundary pressure of 13 atm was chosen based on the steam parameters in the general station steam collector. This implies that when starting from a hot state, the purge steam can immediately be directed to the ignition ROU.

During launches, the following general principles should be observed:

1. The start-up of the boiler includes three stages:

Preparatory stage;

Ignition of the boiler and raising the parameters;

Inclusion of the boiler in the general station steam collector.

To optimize and improve the quality of preparatory operations, start-up schedules should be used that regulate the sequence of operations, the time for carrying out one or another operation and the person responsible for performing this operation. These graphs allow you to determine the execution of preparatory operations for any point in time.

From the moment the boiler is fired up and until the moment it is brought to the nominal parameters of the steam, the operating personnel must be guided by the so-called schedule - the start task, which is a curve of pressure change in the drum, associated with a graph of the temperature of superheated steam, indicating the moments of boosting the furnaces and parameters for carrying out preventive measures (purges, switching on sampling points, connecting RRDS, etc.). Schedules - tasks and network schedules should be developed from all thermal states of the boiler.

t met

2. Initial fuel consumption during cold starts should be approximately 10% of nominal. At the same time, since this fuel consumption lies in the insensitivity zone of gas (fuel oil) flow meters, the control of the amount of supplied fuel should be carried out according to the maximum gas temperature at the outlet of the furnace, which, for example, for ultra-high pressure boilers should be at least 420 - 440 o C according to the conditions of uniformity of the gas temperature field and ensuring a sufficient heating rate of the elements and not higher than 540 o C under the conditions of reliable cooling of the superheater with low heat removal from the steam side.

3. When starting from an uncooled and hot thermal state, the initial fuel consumption should be 15–20% of the nominal, and the maximum gas temperature at the outlet of the furnace should be 10–30 ° C higher than the maximum temperature of the superheater metal, so that in the initial point in time there was no decrease in the pressure of the superheated steam.

4. A slow increase in the initial steam pressure during cold start-ups should be ensured by fully opening the superheater purge, additional purge from the superheater section and full opening of the air vents from the boiler steam path and from the steam pipelines. At the same time, it is necessary to achieve the slowest possible increase in steam pressure with a relatively rapid increase in steam production, which will ensure good ventilation of the drum, "breathing" of the boiler.

5. The heating rate of the boiler drum should be controlled by the rate of increase in the temperature of the metal of the lower generatrix of the drum, which should not exceed 30 ° C in 10 minutes.

Due to the complexity of regulating the rate of increase in the temperature of the metal of the lower generatrix of the drum due to fuel consumption or the magnitude of the blowdown of the superheater, it is recommended that the moments of forcing the furnaces be reflected in the schedule - the start task. In this case, kindling nozzles must be used. In this case, the amount of fuel supplied to the furnace at the moments of forcing can be regulated by the number of ignited nozzles and the pressure in front of them.

Warming up the drum is not a mandatory operation, subject to the above recommendations, since in this case the safety criterion is based on the temperature difference between the upper and lower generatrices of the drum (60 ° C) can be carried out with heating of the drum from a third-party source.

6. The boiler is considered empty if the water level in the drum is below the firing level.

The water path of the boiler must be filled with deaerated water, while the temperature difference between the water and the metal of the drum must not exceed 40 - 60 ° C. The temperature difference between the metal of the upper and lower generatrices of the drum after filling must not exceed 80 ° C. It is not allowed to fill the drum at the temperature of the metal drum is higher than 160 ° C. Hydropressure of the steam-water path of the boiler is not allowed if the temperature of the metal of the lower generatrix of the drum exceeds 150 ° C.

Filling the boiler should be done slowly, especially in the first minutes. In this case, the temperature difference of the metal of the right and left generatrixes of the drum, the upper and lower generatrixes of the drum must be strictly controlled.

It is considered the most rational to fill the water path of the boiler through the lower collectors of the screens, namely through the drainage system, which contributes to a better displacement of air from the water path.

7. The duration of periodic purges from the lower points of the screens during starts and stops should be from 1.5 to 3 minutes. In stationary modes of operation of the boiler, the frequency of blowdowns and the time of their implementation is regulated by the personnel of the chemical department (usually at least 1.5 minutes once every 2-3 days for each screen).

To increase the efficiency of periodic blowdowns in the lower collectors of the screens, it is recommended to install sludge collectors or install additional drainage lines.

On boilers of non-unit TPPs, subject to the above requirements, there is practically no need to control the temperature of the superheated steam during the kindling period until the moment the boiler is connected to the plant-wide live steam collector.

Emergency injections are used extremely rarely. At the same time, their use for controlling the temperature of superheated steam should be carried out in agreement with the personnel of the chemical shop.

Regular injections are connected when the nominal steam temperature is reached. When using regular injections, it is necessary to load the first injections in the course of the steam as much as possible and connect, if necessary, the following ones.

It should also be noted that when the boiler is idle in reserve for more than three days, before starting, protections and interlocks should be tested with preliminary scrolling of the protective fittings and control of its serviceability in place.

8. To simplify launch operations, the RRDS should be kept in a hot reserve. This means that the RRDS from the high side (steam pipelines from the boiler to the valve at the RRDS inlet) must be heated by steam from the boiler, and from the low side (steam pipelines from the valve at the RRDS inlet to the TPP auxiliary steam collector) - by steam from the SPV.

The quality of the launch operations should be evaluated, and appropriate measures should be taken to eliminate the problems that arise. For this purpose, the operational personnel fills in the appropriate sheets, which include the criteria for safe operation and the main provisions on the organization of boiler start-ups.

RUSSIAN JOINT STOCK COMPANY ENERGY
AND ELECTRIFICATION "UES OF RUSSIA"

STANDARD INSTRUCTIONS
ON LAUNCH
FROM VARIOUS THERMAL STATES
AND I WILL STOP THE BOILER
THERMAL POWER PLANTS
CROSS-LINKED

RD 34.26.514-94

SERVICE OF EXCELLENCE ORGRES

Moscow 1995

DEVELOPED by ORGRES Firm JSC

CONTRACTOR V.V. KHOLSHCHEV

APPROVED by RAO "UES of Russia" on September 14, 1994.

First Vice President V.V. CURLY

The Instruction takes into account the comments and suggestions of research and design institutes, energy enterprises and adjustment organizations.

RD 34.26.514-94

Expiry date set

from 01.01.1995

until 01.01.2000

The standard instruction is intended for engineering and technical personnel of thermal power plants. This Manual is being reissued. From similar works, the “Collection of instructions for servicing power plant boilers” (M.-L .: Gosenergoizdat, 1960), “Temporary instruction for servicing a TGM-84 type boiler when burning natural gas and fuel oil” (M .: BTI ORGRES, 1966).

When operating the boiler, you should be guided by the requirements:

current PTE, PTB, PPB, "Rules for the Design and Safe Operation of Steam and Hot Water Boilers", "Explosion Safety Rules for the Use of Fuel Oil and Natural Gas in Boiler Installations";

factory operating instructions for the boiler;

local instructions for the maintenance and operation of the boiler and auxiliary equipment;

local job descriptions;

. GENERAL PROVISIONS

The procedure for switching on automatic regulators when starting the boiler is given in the appendix.

The basic principles of organizing the modes of starting and stopping the boiler are set out in the appendix.

The scope of temperature control is given in the appendix.

In the process of filling, turn on the dosing pumps of the conservation plant to supply the hydrazine-ammonia solution (Fig. ) to one of the possible points on the boiler (drum, lower points, power unit). When full, turn off the dosing pumps and connect the boiler to the hot (or cold) feed water assembly; make a pressing.

During pressure testing, take a sample and determine the quality of water in the boiler, including visually. If necessary, flush the screen system through the lower points until the boiler water is clarified. The concentration of hydrazine in the boiler water should be 2.5 - 3.0 mg/kg, pH > 9.

steam valves PP-1, PP-2 for blowing the boiler into the atmosphere;

steam valves PP-3, PP-4 from the section of the superheater into the atmosphere;

turn on the dosing pumps at the request of the chemical workshop and organize the phosphating mode in the absence of phosphates in the boiler water, maintaining the pH value of the boiler water of the clean compartment at least 9.3;

set the required flow rate of boiler water from remote cyclones by covering the continuous blowdown control valve, making sure that the quality indicators of feed water and steam are stabilized at the standard level.

. START-UP OF THE BOILER FROM THE UNCOOLED STATE

. BOILER START FROM HOT STATE

. STOP THE BOILER TO STANDBY

Turn on moment

Lowering the water level in the boiler drum

When the pressure in the drum reaches 13.0 - 14.0 MPa and the readings of the level gauges are compared with the readings of direct-acting water-indicating instruments

Increasing the water level in the boiler drum (limit II)

Extinction of the torch in the furnace

At a load of 30% of the rated

Decrease in gas pressure after the control valve

With the opening of the gas valve to any burner

Reducing the oil pressure after the control valve

With the opening of the oil valve to any burner

Reducing the oil pressure in the lubrication system of mills with direct injection with its centralized supply

Switching off all primary air fans

Shutdown of all mill fans when transporting dust with a drying agent from these fans

Tarnishing of the pulverized coal torch in the furnace

Shutdown of all smoke exhausters

With the opening of the fuel shut-off valve to any kindling burner

Shutdown of all blowers

Disabling all RWPs

Failure to ignite or extinguish the flame of any pilot burner

Function at start

Turn on moment

Kindling water level regulator in the drum

Maintaining a constant level

After switching to the control valve on the bypass with a diameter of 100 mm of the power unit

Drum water level regulator

After switching to the main PKK

fuel regulator

Maintaining fuel consumption in accordance with the task

According to local regulations

Live steam temperature controller downstream of the boiler

Maintenance of the nominal temperature of live steam by means of injection

When the nominal temperature of live steam is reached

Continuous purge controller

Maintaining a predetermined flow rate of continuous purge

After turning on the boiler in the main

General air regulator

Maintaining a given excess of air in the furnace

Primary air flow regulator

Maintaining a predetermined primary air flow

After switching to dust incineration

Vacuum regulator in the furnace

Maintaining vacuum in the furnace

With boiler ignition

Annex 3

BASIC PRINCIPLES OF THE ORGANIZATION OF START AND STOP MODES OF THE BOILER

Earlier, as is known, it was proposed to control the temperature of the water in front of the drum when filling the hot boiler, which should not differ by more than 40 ° C from the temperature of the metal at the bottom of the drum. However, this requirement can be met only if the first portion of water is sent in addition to the drum. Existing schemes for supplying water to the boiler drum usually do not provide for such a possibility. Nevertheless, when developing a scheme for monitoring the temperature state of the drum, it was decided to keep the measurement of the water temperature in front of the drum; the saturation temperature control is also retained.

Filling the drum for hydropressing is prohibited if the temperature of the metal of the top of the empty drum exceeds 140 °C.

The graphs given in the tasks for firing up the boiler from various thermal states are of a specific nature: the testing of starting modes was carried out on the TPE-430 boiler of a thermal power plant with cross connections; The graphs also apply to boilers of other types.

Rice. 9 . Temperature distribution along the superheater path:

Depending on the technology used, boiler shutdowns are divided into the following groups:

shutdown of the boiler in reserve;

shutdown of the boiler for a long-term reserve or repair (with conservation);

shutdown of the boiler with cooldown;

Emergency Stop.

Boiler standby shutdown refers to a short shutdown while keeping the water level in the drum, mainly due to downtime of non-repairable equipment over the weekend. During a shutdown lasting more than 1 day, the pressure in the boiler, as a rule, decreases to atmospheric pressure. When shutting down for more than 3 days, it is recommended to put the boiler under excess pressure from a deaerator or other source for conservation purposes.

The boiler shutdown technology is adopted as simplified as possible and provides for unloading the boiler up to 20 - 30% at nominal parameters, followed by its redemption and disconnection from the main steam pipeline.

To maintain steam pressure during shutdown, the boiler purge valves to atmosphere are not opened. The requirement contained in the "Scope and technical conditions for the implementation of technological protection of thermal power equipment of power plants with cross connections and hot water boilers" (Moscow: SPO Soyuztekhenergo, 1987), on the opening of purge valves during boiler shutdowns, was revised and when listing the actions performed by technological protection, this operation is not mentioned (Circular No. Ts-01-91 / T / “On Amending the Technological Protection Schemes of Thermal Power Equipment of Operating TPPs” - M .: SPO ORGRES, 1991).

It is enough to confine ourselves to the remote control of the purge valves.

When equipment is put into long-term reserve or repair, this Standard Instruction provides for its conservation with hydrazine with ammonia in the boiler shutdown mode. Other preservation methods are also possible.

Shutdown with cooldown of the boiler and steam pipelines is used if it is necessary to repair the heating surfaces in the furnace, gas ducts, warm box. When the boiler is extinguished, the draft machines remain in operation for the entire cooldown period. The drum is cooled down by the steam of a neighboring boiler (through jumpers) both without maintaining the water level in the drum (such a mode is given as an example in this Standard Instruction) and with maintaining the level. In the latter case, the supply of steam for cooling down is carried out only in the upper collectors of the drum. With the help of RRDU, the rate of pressure reduction of steam, which is first discharged into the auxiliary collector, then into the atmosphere, is regulated.

The steam pressure reduction rate must be maintained in such a way as not to exceed the allowable rate of temperature decrease in the lower generatrix of the drum, which at shutdown is [↓Vt] = 20 °C/10 min. The temperature difference between the upper and lower generatrices of the drum should not exceed [ Dt] = 80 °C.

Appendix 4 SCOPE OF TEMPERATURE CONTROL

It is advisable to control the temperature regime of the superheater during boiler start-ups with standard thermoelectric thermometers installed at the outlet of individual stages, refusing to measure with coil thermoelectric thermometers. In start-up modes, first of all, it is necessary to ensure control over the steam temperature in the first stages of the superheater as the most heat-stressed heating surfaces in such modes, as well as over the steam temperatures at the boiler outlet in both flows. It is recommended to bring these measurements to automatic registration along with the existing drum metal temperature registration. The latter must be brought into line with the requirements of the application of Sec. 1.6 "Collection of administrative documents for the operation of energy systems (Heat engineering part). Part 1." M.: SPO ORGRES, 1991:

the number of temperature measurements along the top-bottom drum was reduced to six: in the center and in the extreme sections;

measurement of saturation temperatures is provided by installing sleeve or surface thermocouples on the steam outlet and drain pipes of the drum;

it is provided to measure the temperature of the feed water behind the economizer (for control when filling the drum).

RUSSIAN JOINT STOCK COMPANY ENERGY
AND ELECTRIFICATION "UES OF RUSSIA"

STANDARD INSTRUCTIONS
ON LAUNCH
FROM VARIOUS THERMAL STATES
AND I WILL STOP THE BOILER
THERMAL POWER PLANTS
CROSS-LINKED

RD 34.26.514-94

SERVICE OF EXCELLENCE ORGRES

Moscow 1995

DEVELOPED by ORGRES Firm JSC

CONTRACTOR V.V. KHOLSHCHEV

APPROVED by RAO "UES of Russia" on September 14, 1994.

First Vice President V.V. CURLY

The Instruction takes into account the comments and suggestions of research and design institutes, energy enterprises and adjustment organizations.

RD 34.26.514-94

Expiry date set

from 01.01.1995

until 01.01.2000

When operating the boiler, you should be guided by the requirements:

current PTE, PTB, PPB, "Rules for the Design and Safe Operation of Steam and Hot Water Boilers", "Explosion Safety Rules for the Use of Fuel Oil and Natural Gas in Boiler Installations";

factory operating instructions for the boiler;

local instructions for the maintenance and operation of the boiler and auxiliary equipment;

local job descriptions;

instructions of environmental authorities, recommendations of commissioning and research organizations.

. GENERAL PROVISIONS

The basic principles of organizing the modes of starting and stopping the boiler are set out in the appendix.

The scope of temperature control is given in the appendix.

. START-UP OF THE BOILER FROM THE UNCOOLED STATE

Turn on moment

Lowering the water level in the boiler drum

When the pressure in the drum reaches 13.0 - 14.0 MPa and the readings of the level gauges are compared with the readings of direct-acting water-indicating instruments

Raising the water level in the boiler drum ( II limit)

Extinction of the torch in the furnace

At a load of 30% of the rated

Decrease in gas pressure after the control valve

With the opening of the gas valve to any burner

Reducing the oil pressure after the control valve

With the opening of the oil valve to any burner

Reducing the oil pressure in the lubrication system of mills with direct injection with its centralized supply

Switching off all primary air fans

Same

Shutdown of all mill fans when transporting dust with a drying agent from these fans

-»-

Tarnishing of the pulverized coal torch in the furnace

-»-

Shutdown of all smoke exhausters

With the opening of the fuel shut-off valve to any kindling burner

Shutdown of all blowers

Same

Disabling all RWPs

-»-

Failure to ignite or extinguish the flame of any pilot burner

-»-

Appendix 2 ORDER OF TURNING ON AUTOMATIC REGULATORS WHEN STARTING THE BOILER

Function at start

Turn on moment

Kindling water level regulator in the drum

Maintaining a constant level

After switching to the control valve on the bypass with a diameter of 100 mm of the power unit

Drum water level regulator

Same

After switching to the main PKK

fuel regulator

Maintaining fuel consumption in accordance with the task

According to local regulations

Live steam temperature controller downstream of the boiler

Maintenance of the nominal temperature of live steam by means of injection

When the nominal temperature of live steam is reached

Continuous purge controller

Maintaining a predetermined flow rate of continuous purge

After turning on the boiler in the main

General air regulator

Maintaining a given excess of air in the furnace

Same

Primary air flow regulator

Maintaining a predetermined primary air flow

After switching to dust incineration

Vacuum regulator in the furnace

Maintaining vacuum in the furnace

With boiler ignition

Annex 3

BASIC PRINCIPLES OF THE ORGANIZATION OF START AND STOP MODES OF THE BOILER

In this case, it is possible to reduce the duration of the purge to 50–60 s with a frequency of once every 4–6 days.

9 . Unlike block-type boilers, on boilers connected to the main, there is practically no need to regulate the temperature of fresh steam until reaching the nominal parameters, after which the regular injection system is turned on. The presence of a special starting injection of feed water is not necessary. On the graphs-tasks, the increase in the temperature of fresh steam during the start-up process is conventionally depicted by a straight line.

10 . One of the common causes of damage to the superheater is the operation of the boiler with a non-optimal distribution of injections. Firstly, when selecting control valves, it is necessary to pay attention not only to their diameter, but also to the version number, on which the consumption of own condensate for injection depends. And, secondly, when regulating, it is necessary to adhere to the principle of maximum reduction in steam temperature with the help of the first injection along the steam path and the minimum temperature difference with the help of the final injection, up to 0 (

12 . Depending on the technology used, boiler shutdowns are divided into the following groups:

shutdown of the boiler in reserve;

shutdown of the boiler for a long-term reserve or repair (with conservation);

shutdown of the boiler with cooldown;

Emergency Stop.

13 . The boiler shutdown technology is adopted as simplified as possible and provides for unloading the boiler up to 20 - 30% at nominal parameters, followed by its redemption and disconnection from the main steam pipeline.

It is enough to confine ourselves to the remote control of the purge valves.

14 . When equipment is put into long-term reserve or repair, this Standard Instruction provides for its conservation with hydrazine with ammonia in the boiler shutdown mode. Other preservation methods are also possible.

15 . Shutdown with cooldown of the boiler and steam pipelines is used if it is necessary to repair the heating surfaces in the furnace, gas ducts, warm box. When the boiler is extinguished, the draft machines remain in operation for the entire cooldown period. The drum is cooled down by the steam of a neighboring boiler (through jumpers) both without maintaining the water level in the drum (such a mode is given as an example in this Standard Instruction) and with maintaining the level. In the latter case, the supply of steam for cooling down is carried out only in the upper collectors of the drum. With the help of RRDU, the rate of pressure reduction of steam, which is first discharged into the auxiliary collector, then into the atmosphere, is regulated.

16 . The steam pressure reduction rate must be maintained in such a way as not to exceed the allowable rate of temperature decrease in the lower generatrix of the drum, which at shutdown is [↓ V t ] = 20 °С/10 min. The temperature difference between the upper and lower generatrices of the drum should not exceed [ Dt] = 80 °C.

Appendix 4 SCOPE OF TEMPERATURE CONTROL

the number of temperature measurements along the top-bottom drum was reduced to six: in the center and in the extreme sections;

measurement of saturation temperatures is provided by installing sleeve or surface thermocouples on the steam outlet and drain pipes of the drum;

it is provided to measure the temperature of the feed water behind the economizer (for control when filling the drum).

Reliable flow of intra-boiler processes necessary for uniform heating of the boiler elements must be ensured.

The heating temperature of the elements should not exceed the value that is set by the allowable temperature parameters of the metal:

- coefficient of linear expansion;

E is Young's modulus of elasticity;

- Poisson's ratio;

- the temperature difference that occurs during heating;

- characterizes the heating mode;

- in stationary mode;

- at start-up;

- with thermal shock;

The main defining parameters characterizing the start-up mode.

A). cold state:
, which is achieved when the boiler is idle for more than two days;

b). cold state:
. Downtime of 10 hours or more;

V). hot state:
.

The choice of a boundary pressure of 1.3 MPa is due to the fact that the steam pressure in the station's auxiliary collector is 1.3 MPa. When starting from a hot state, the steam generated by the boiler can be immediately sent to the auxiliary collector.

When starting the boiler from various states, the following fuel consumptions are observed:

However, after ignition
gas burner or nozzle. The temperature of the gases in the revolving chamber must not exceed

Starting a drum boiler of a non-block TPP from a cold state.

Startup includes the following steps:

Preparatory stage starts after the command of the station shift supervisor to start the boiler. In doing so, the following actions are performed:

checking the possibility of launching (presence of a supply of fuel, deaerated water, etc.).

bypassing the equipment of the boiler plant (they check compliance with safety regulations, the serviceability of the equipment, preparations are underway to fill the boiler with water).

filling the boiler with water. Testing of technological protections and interlocks. Preparing the boiler for kindling.

Before starting the boiler, the following parameters are monitored:

,
,
,
, expansion of the drum, the temperature difference between the metal of the drum of the upper and lower generatrices and along the length. The thermal state of the boiler is determined.

The source of filling the boiler with water is selected. In this case, the following conditions must be met:

The difference between the temperature of the water and the temperature of the metal of the drum must be less than 40°C.

The boiler is filled with deaerated water. The duration of filling, depending on the power of the boiler, is 1.5-2 hours.

When filling the boiler with water, the air vents on the drum and in other elements of the boiler must be open to expel the air. The boiler is filled to a level approximately 50 mm below zero.

During the filling of the mill, smoke exhausters, etc. equipment is transferred to the test position, i.e. they are disconnected from high voltage circuits. This is necessary for testing the boiler protections, since during testing of the protections this equipment must be turned off, and restarting will cause overheating of the stator and rotor windings.

In the event of a protection failure, the boiler start-up is prohibited.. Registration of protection failures is carried out in the operational log.

After testing the protections, the boiler is prepared for kindling. Namely: the ignition level is set in the drum, the electrical circuits of the equipment are put into working condition, the circuit of the oil ring is assembled. Due to recirculation, the temperature of the fuel oil rises to 100-120°C.

When kindling on gas, a gas ring diagram is assembled. Gas supply to the gas ring is allowed only after the start-up of draft machines. When filling gas pipelines, the oxygen content in the gas is controlled (
).

When kindling on fuel oil, after the performed operations, it is necessary to assemble the boiler kindling scheme, which includes the elements necessary for heating the steam pipeline from the boiler steam collecting chamber to the steam line and devices that utilize superheated steam.

PPP-1 - the first blowdown of the superheater;

PPP-2 - the second blowdown of the superheater;

GPZ - main steam valve;

PM - steam line;

KSN - collector of own needs;

Dr - drainages;

RD - pressure regulator;

RROU - kindling ROWE. It is necessary to reduce steam parameters.

PC - safety valve.

Open purge PPP-1 and PPP-2; GPZ-1; Dr-2; air vent on the steam chamber B1 and B2; The RRW should be on standby (under pressure from the SPC).

Close GPZ-2 and bypasses GPZ-1, GPZ-2, valves for emergency and working injections.

Boost stage

Before ignition of the first burner, it is necessary to ventilate the furnace and boiler flues for at least 10 minutes:
.

At the end of ventilation, air is taken from the upper part of the furnace (a sample is taken for the absence of methane (
) in the air).

The vacuum in the upper part of the furnace is set to 4-5 mm of water st.

The kindling of the boiler is carried out with the help of kindling burners, which are switched on in a certain sequence.

After the start of kindling and the start of steam formation, the PE, the drum and the connecting manifold are heated. The heating of the metal of the superheater is regulated by the amount of purge PPP-1 and PPP-2; heating of the connecting collector is carried out due to the exit of the heating steam condensate through drain-2, while drain-1 must be closed. When a continuous jet of steam appears through the air vents B-1 and B-2, they close.

The start-up speed of the drum boiler is limited by the conditions for heating the drum of the boiler, as the most thick-walled element.

The rate of rise of the parameters is determined by the rate of heating of the lower generatrix of the drum:

in 10 min.

In this case, the temperature difference between the metal of the upper and lower generatrices of the drum should be no more than 60 °.

Kindling must be carried out at the highest possible speed. Reducing the warm-up rate will cause excessive fuel consumption at start-up.

At
the density of the steam-water path is controlled.

At
the lower points are purged for 2-3 minutes (each collector). At the end of the purge, it is necessary to close PPP-1 and discharge steam only through PPP-2. When the pressure reaches 1.3 MPa, it is necessary to take a sample for the quality of the steam and adjust the water regime of the boiler so as not to reduce the quality of the steam in the KSN.

Conditions necessary to turn on the kindling ROU.

coordinate the inclusion of the RRDS with the chemical shop in order to exclude the reduction in the quality of steam in the SPV and maintain the quality of the feed water;

coordinate this operation with the personnel of the turbine department so that the automatic pressure control devices in the auxiliary manifold are turned on;

turn on continuous blowing.

The RROU is connected in steps, by opening the gate valve at the RROU circuit inlet and shutting off the superheater purge (SPP-2).

Further, the main parameters of the boiler operation, the level in the drum, the temperature difference between the top and bottom of the drum, the expansion of the drum and steam pipelines, etc. are controlled. Next, the subsequent increase in parameters is performed.

in 10 min.

Upon reaching the nominal parameters that correspond to the parameters
in the steam line and achieving the required steam capacity according to the circulation conditions, preparations are made for the inclusion of the boiler in the steam line. At the same time, the main parameters of the boiler are additionally controlled. The performance of the main and auxiliary equipment of the boiler is assessed, the quality of the steam is monitored, and the operators of steam boilers and turbines are warned about the inclusion of the boiler in parallel operation.

5.2.1. Fire up the boiler. Ignite two fuel oil nozzles for what:

Light a torch and bring it under the oil burner. Before opening the valve for fuel oil, it is necessary to apply spray steam with a pressure of 7-8 kgf / cm 2. After stabilizing the pressure in the atomizing steam line, supply fuel oil. Fuel oil pressure at startup 3-5 kgf/cm 2 . After igniting the fuel, use the valves for steam and fuel oil to set the desired operating mode of the nozzle. Burning should be smokeless, the torch should be stable and powerful enough. If dark streaks, smudges, large drops and sparks appearing at the root of the torch appear, the fuel oil nozzle must be extinguished and handed over for repair. The torch must not touch the heating surfaces. It is unacceptable to get fuel oil on the panels of the screens of the furnace and, as a result, on the hearth of the furnace. From time to time, in compliance with PTB measures, it is necessary to control the absence of fuel oil on the furnace screens and its flow through the tap-hole into the SHV. The control is carried out through tapholes and inspection hatches of the furnace, the oil-oil injectors embrasure. If fuel oil is found on the heating surfaces or in the SHV, stop the kindling, wash off the spilled fuel oil with hot water. Turn off fuel oil nozzles giving poor-quality spray and hand over for repair for revision;

It must be remembered that when fuel oil is ignited, a sharp increase in the volume of combustion products occurs. With insufficient vacuum in the furnace, pressure arises with the knocking out of gases outside the furnace. Before igniting the oil burner, set the vacuum to at least minus 10-20mm. v.st. ”, followed by immediate adjustment by influencing the directing vane DS;

After the first nozzle, light the second in another pre-furnace.

Kindling should be carried out on at least two nozzles. If, when the first fuel oil burner is ignited, the fuel oil does not immediately ignite, or if all operating nozzles go out, immediately close the valve on the fuel oil supply to the nozzles. Determine the cause of the flame failure and eliminate it. After finding out and eliminating the reasons for the extinguishing of the fuel oil burners, start firing them up again (after 10 minutes of ventilation of the boiler). Tubes with fuel oil nozzles installed in them must be closed with regular dampers during the operation of the fuel oil nozzle.

The operator-crawler for KO, who controls the operation of the nozzles until they burn steadily (the temperature in the turning chamber is not lower than 250 ° C and the pressure in the PSC is not less than 30 kgf / cm2) should not be absent for other work. Continuous monitoring of the operation of fuel oil nozzles is terminated with the permission of the senior engineer for KO, NSKTC.

The driver of the central heating control room with boilers, upon detecting the pulsation of the furnace during the kindling period, is obliged to demand from the driver-crawler for KO, who controls the operation of the fuel oil nozzles, to take measures to eliminate the pulsation.

The danger of the presence of spilled fuel oil in the furnace lies in the fact that at a flue gas temperature in the rotary chamber of 200-250 ° C, an outbreak of fuel oil occurs, a sharp increase in the volume of the combustion product in the furnace with the flame knocking out of leaks in the furnace. Inspection of the furnace, inspection of the fuel oil nozzle for the quality of the fuel oil spray should be carried out in a mask with a cape.

As the combustion chamber warms up, switch the operating nozzles in order to ensure uniform heating of the combustion chamber. When igniting oil burners, you must not stand in front of hatches, nozzle installation sites, so as not to be burned by an accidental flame ejection. The KO operator who ignites the fuel oil and controls the operation of the fuel oil nozzle must be in a mask with a cape.

From the moment the boiler is kindled, organize control over the water level in the drum according to the VUP. Make sure that before starting the kindling, the level in the drum is kindling. Reduced water level indicators should be checked against water-indicating devices during the kindling process, taking into account the amendments. The transition to control over the water level in the drum using reduced level indicators is made after their readings coincide with the readings of the water-indicating columns.

Fire up the boiler in accordance with the schedule-task for starting the boiler from a cold state (Fig. 9 and all graphs, start-up lists), regulatory documentation for starting and stopping the boiler.

5.2.2. In the event of excess pressure, close the air vent valves in the boiler.

5.2.3. At a pressure in the drum of 0.3 MPa, proceed to the first purge of the VUK. Close the drains from the GPC rolls.

The procedure for purge VUK:

Open the purge valve - the water and steam pipes and glass are purged;

Close the water valve - the steam pipe and glass are blown;

Open the water valve, close the steam valve - the water tube is blown;

Close the purge valve, open the steam valve and check the water level (check with another dispenser).

Fig.9. Graph of pressure rise in the boiler drum during kindling

The water level at the first moment after the closure of the drainage should rise rapidly, then fluctuate slightly at the middle position. A slow rise in the water level indicates a blockage in the water line. If the water fills the entire column, then the steam line is clogged. In both cases, the purge should be repeated.

Re-purging of water-indicating columns should be carried out at a pressure in the drum of 1.5-3.0 MPa.

The transition to control over the water level in the drum according to the reduced level indicators is made only after their readings coincide with the readings of the water-indicating columns.

5.2.4. At a pressure in the drum of 0.3-0.4 MPa, it is necessary to blow out the lower chambers of the screens.

The duration of the purge of each collector is no more than 30 seconds.

Only one point is blown at a time.

When purging, make sure (by sound and feel) that the purge points are working properly and are not clogged. If the line is clogged, take measures to clean it up to the end of the boiler firing.

Re-purge should be performed at a pressure in the drum of 2.0-3.5 MPa, if necessary, suspending the increase in parameters until the end of the purge.

Open P-1 with heating of the steam pipeline through the drain to the funnel in front of P-2.

During the kindling period, the rate of increase in the saturation temperature, based on the allowable thermal stresses of the walls of the boiler drum and the allowable temperatures of the walls of the superheater, should not exceed 1.5 ° C per minute, then the increase in pressure in the boiler will proceed approximately in accordance with the schedule of pressure increase in the boiler and the duration of kindling will be about 3.5-4 hours (Fig. 9). The rate of kindling must be controlled by the saturation temperature. To reduce the inertia, this temperature should be viewed on one of the steam pipes in the middle of the drum.

5.2.5. At a pressure in the drum of 1.0-1.5 MPa, turn on continuous blowing by opening the control valves fully. Next, the POT is purged, samples are taken for chemical analysis. Make up the boiler if necessary. Close the superheater drain valves. Transfer the drains in front of P-2, and from the kindling steam pipeline to the HPHP with the drainage valves closed to the funnel.

5.2.6. At a pressure of 1.5 MPa in the drum, ignite 2 additional fuel oil nozzles.

5.2.7. At a pressure in the drum Pb=2.0 MPa, switch the steam supply to the ignition steam pipeline (with satisfactory analyzes of superheated steam), for which open the steam valves R-1; R-2; R-3; close PR-1; PR-2, provided that the temperature difference between the top and bottom of the drum does not exceed 40°C. The steam flow rate at the RRDU is set from the condition of maintaining the required rate of pressure rise in the boiler and sufficient cooling of the superheater coils. To protect the coils of the superheater from overheating, it is advisable to kindle the boiler before it is connected to the main line with increased excess air. Carry out a bypass of the boiler in order to check its good condition and hydraulic density, to verify the VUP.

5.2.8. With further loading of the boiler, the RD RROU valve opens and the RROU remains in operation until the boiler is connected to the main. To the operator of the TsTSCHU with boilers (in his absence, the senior operator of the CO of the CHTC), where the control circuits of the RRDS are located, ensure constant pressure and temperature on the low side of the RRDS.

5.2.9. Periodic restoration of the water level in the drum is carried out using ShDK-1. Make-up should be carried out with a closed recirculation line "drum - VEC" (RTs-1, RTs-2). Keep the level in the drum within ± 100 mm from normal before switching to constant power supply of the boiler, and ± 50 mm from normal after switching to constant power.

5.2.10. Increase, according to the graph of pressure rise in the boiler drum during kindling (Fig. 9), the fuel consumption to approximately 24% of the nominal, by increasing the consumption of fuel oil for fuel oil nozzles.

5.2.11. Switch from periodic to constant power supply of the boiler, for which:

Close the valves RTs-1, RTs-2 on the recirculation line “drum-economizer;

According to the standard temperature control of the metal, check the tightness of the shutdown of the recirculation line drum - economizer;

Turn on the water level regulator in the drum with the impact on the ShDK-1;

Check the operation of the level controller.

5.2.12. When kindling the boiler, it is necessary to monitor the temperatures of the metal of the superheater coils.

5.2.13. Organize the boiler kindling mode in such a way that the temperature of the metal does not exceed the allowable one (see section 6, paragraphs 6.7, 6.10).

In case of insufficient cooling of the pipes by the flowing steam, the kindling mode should be changed in order to prevent an excessive increase in the temperature of the gases in the area of the superheater.

In addition, to protect the metal of the furnace screen coils during kindling, a kindling desuperheater with feed water injection is installed on the boiler. At the same time, it is necessary to ensure that the temperature of the steam after the desuperheater is at least 30˚С higher than the saturation temperature of the steam to prevent water from being thrown into the superheater (with a temperature difference between the top and bottom of the injection manifold not more than 40˚С).

5.2.14. When kindling the boiler, organize control over the temperature regime of the drum. The heating rate of the lower generatrix of the drum should not exceed 30˚С in 10 minutes, and the temperature difference between the upper and lower generatrix of the drum should not exceed 60˚С.

5.2.15. In the process of kindling, control the pH of the feed and boiler water. The pH of the feed water before the WEC is 9.0 - 9.2, after the WEC - 8.5, the pH of the boiler water in the clean compartment should be 9.0 - 9.5, and in remote cyclones (salt compartment) no more than 10.5.

5.2.16. Control the temperature of the superheated steam along the path. At temperatures exceeding the allowable values, turn on the appropriate injections or suspend loading the boiler with fuel.

5.2.17. In the process of firing up the boiler, it is necessary to monitor the uniform expansion of all boiler elements along specially installed benchmarks and check that the movements of the boiler elements correspond to the factory thermal expansion scheme (Fig. 6). In case of jamming of cameras or other elements, it is necessary to establish the cause of the jamming and eliminate it. At a pressure in the boiler drum of 3.5 MPa, check the thermal displacement of the boiler elements, with an entry in the operational log.

5.2.18. Checking the thermal displacement is carried out when the boiler is kindled from a cold state after a major and medium repair, but at least once a year.

5.2.19. When the pressure in the boiler drum is 4.0 MPa, turn off the steam heating of the bottom of the drum.

5.2.20. At a pressure in the boiler drum of 5-7 MPa, which corresponds to a steam load of 130 t/h, switch the boiler to burning coal dust. Oil nozzles must remain in operation.

The procedure for switching to dust incineration:

Turn on the dust system;

Open the shut-off gates above the dust feeders;

In turn, at minimum speed, turn on the dust feeders of the lower tier of burners, having previously opened the steam supply to the PVK ejectors, the dust feeders of the upper tier of the burners are put into operation after stable combustion of the dust supplied to the burners of the lower tier.

After turning on the burners, adjust the combustion mode by changing the flow rates of dust and air.

5.2.21. During kindling, carefully control the flue gas temperature along the convection shaft and the air temperature behind the air heater. If there are signs of a fire, inspect the gas ducts, stop kindling, stop smoke exhausters and blowers, close their guide vanes and turn on the fire extinguishing system.

5.2.22. Before connecting the boiler to a common steam line, check the quality of saturated and live steam. The inclusion of the boiler in the main is allowed when the silicon content of the steam is not more than 60 μg / dm 3. Before starting operations to turn on the boiler, check the readings of the lowered level indicators with the readings of the water-indicating columns, check the water level, and also compare the readings of the upper and lower boiler pressure gauges to make sure their readings are correct. To put into operation the regulator of vacuum in the furnace and air supply to the boiler.

5.2.23. When starting the boiler unit for the first time, after a major overhaul, as well as after repairing the IPC and GPC, when the operating pressure of the superheated steam is reached, the pulse-safety valves are adjusted before being connected to the main.

5.2.24. The inclusion of the boiler in the common steam pipeline must be carried out after draining and warming up the connecting steam pipeline. The steam pressure behind the boiler when switched on must be equal to the pressure in the common steam pipeline. Upon reaching the superheated steam parameters close to those in the line, open the bypass of the main steam valve P-2, increase the fuel consumption up to 30%. Inform the personnel of the thermal shields by radio search communication about the forthcoming inclusion of the boiler in the main.

5.2.25. Connect the boiler to the mains by opening the bypass P-2 and the main steam valve P-2. Simultaneously put into operation the next group of pulverized coal burners, increasing the fuel consumption to 35-40% of the nominal value. Avoid prolonged and significant (more than 20˚С) decrease in steam temperature when connected to the pipeline.

5.2.26. Close the valves R-1; P-2, and bypass of the ignition steam pipeline.

5.2.27. With stable combustion in the furnace, turn off the fuel oil nozzles.

5.2.28. With further loading of the boiler, turn on the rest of the pulverized coal burners.

5.2.29. Put into operation the protection and automatic regulators of the boiler unit.

5.2.30. After loading the boiler:

Redistribute the injections of the superheated steam temperature control system in an optimal way, i.e., the maximum reduction in steam temperature with the help of injection controllers of the 1st stage and the minimum temperature difference with the help of injection controllers of the 2nd stage;

If there is ash in the ash collector bins above the lower level, turn on the PSZ system;

Switch on the phosphate dosing pumps at the request of the chemical workshop and organize, in the absence of phosphates in the boiler water, the phosphating mode, maintaining the pH value of the clean compartment boiler water within 9.0 - 9.5;

After eight hours of boiler operation, by closing the continuous blowdown control valves, set the required flow rate of boiler water from remote cyclones, in agreement with the National Agricultural Center, with water and steam quality indicators at the standard level.

The electrical conductivity of the boiler water must not exceed 20 µS/cm.