RU2737572C1 - Method of optimizing combustion process of hydrocarbon fuel in boiler - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to power engineering, in particular to methods for burning hydrocarbon fuel of variable composition in heat power engineering, industrial heat engineering, industries, housing and communal services. Method for optimization of combustion process of hydrocarbon fuel in boiler includes continuous measurement of fuel consumption in boiler and the heat flow in the heat carrier at the boiler outlet, determination of deviations of the measured values from the previous values and subsequent change in the air flow rate depending on the increase or decrease of the heat flow. Based on the measured values, specific fuel consumption is determined per 1 Gkal of heat, calculating the ratio of the amount of fuel consumption to the value of the heat flow in the heat carrier at the outlet of the boiler, wherein at the beginning of optimization of the fuel combustion process, a one-time discrete increase in the air flow rate is performed to determine the tendency of the heat flow value change in the heat carrier towards the increase or decrease, at that, in order to obtain an optimum fuel-air ratio with increase of the heat flow value, air is continued to increase until the heat flow reduction start, at reduction of heat flow value air is reduced till the moment of heat flux reduction begins.

EFFECT: technical result is optimization of combustion process of hydrocarbon fuel in boiler due to minimization of fuel consumption for generation of heat energy, which is communicated to heat carrier, and, accordingly, provision of maximum complete combustion of fuel.

3 cl, 4 dwg

Description

The invention relates to methods of combustion of hydrocarbon fuel of variable composition in heat power engineering, industrial heat power engineering, industries, housing and communal services. Designed primarily for the combustion of pipeline gas, mixtures of hydrocarbons of undetermined composition, such as associated gas, oil and gas processing waste.

There is a known method for automatic optimization of the combustion process in a boiler (RF patent No. 2647940, IPC F23C 1/02, F23C 1/08, published on 03/21/2018), based on continuous measurement of fuel consumption and temperature of the coolant at the outlet of the heat exchanger of the fuel-burning device, in which a single reduction of fuel consumption, which makes it possible to specify the tendency of change in specific heat of combustion of the fuel, unknown as a result of arbitrary changes in the composition of the fuel used, synchronize the rate of change in temperature at the outlet of the heat exchanger with the rate of change in fuel consumption, then perform simultaneous and / or non-simultaneous interconnected discrete changes in fuel consumption and supply air into the fuel combustion device according to one of the algorithms of optimizing actions implemented by a computer according to a given program, with the possibility of simplifying the method for optimizing the combustion process and increasing the accuracy of achieving optimal vapors etrov.

The disadvantage of this technical solution is that the values of the coolant temperature at the outlet of the heat exchanger of the fuel-burning device as a parameter that determines the fuel consumption do not reflect and are not an indicator of the required amount (consumed) of fuel, since readings of only the coolant temperature without measuring its amount do not reflect the completeness fuel combustion and, as a result, do not affect the minimization of fuel consumption.

As the closest analogue, a method of automatic optimization of the combustion of hydrocarbon fuel in the furnace of a drum steam boiler was chosen (RF patent No. 2425290, IPC F23N 1/02, published on July 27, 2011), including continuous measurement of parameters characterizing fuel consumption and the amount of heat flux in the coolant at the boiler outlet and calculation of the heat flow introduced into the boiler furnace, determination of the deviations of the measured parameters from the optimal calculated values and the subsequent change in the air flow rate.

In this method, the indicator of the optimality of the combustion process is the boiler efficiency, which is determined by the measured values of the heat flux coming from the furnace to the boiler circulation loop and the heat flux introduced by the fuel into the furnace. The disadvantage of this technical solution is that the correlation measurement of the time shift of the specified heat fluxes and the synchronized ratio of the specified heat fluxes do not reflect the completeness of fuel combustion and, as a consequence, do not affect the minimization of fuel consumption. In addition, the disadvantage of this method is the need for a large number of interrelated actions, the laboriousness and inertia of the process, while adjustment is possible only in cases where both the composition and the specific heat of combustion of the gas are predetermined and known.

The objective of the present invention is to develop a method for optimizing the combustion process of hydrocarbon fuel.

The technical result is to optimize the combustion process of hydrocarbon fuel in the boiler by minimizing fuel consumption for generating heat energy communicated (transmitted) to the coolant, and, accordingly, ensuring the maximum possible completeness of fuel combustion.

The technical result is achieved in that the method for optimizing the combustion of hydrocarbon fuel in the boiler includes continuous measurement of fuel consumption in the boiler and the amount of heat flow in the coolant at the outlet of the boiler, determination of deviations of the measured values from the initially measured values and the subsequent change in the air consumption depending on the increase or a decrease in the heat flux, while, on the basis of the measured values, the specific fuel consumption for the generation of 1 Gcal of heat is determined, calculating the ratio of the amount of fuel consumption to the value of the heat flux in the coolant at the outlet of the boiler, while at the beginning of the optimization of the fuel combustion process, a one-time discrete increase in the consumption is performed air to determine the tendency to change the value of the heat flux in the coolant in the direction of increase or decrease, while in order to obtain the optimal fuel-air ratio, with an increase in the value of the heat flux, the air continues to increase until the moment That the beginning of a decrease in the heat flux, with a decrease in the magnitude of the heat flux, reduce the air until the beginning of the decrease in the heat flux.

The invention is further illustrated by the following drawings.

FIG. 1 - A schematic block diagram of a method for optimizing the combustion of hydrocarbon fuel in a boiler.

FIG. 2 - Diagram of a method for optimizing the combustion of hydrocarbon fuel while reducing the specific consumption of hydrocarbon fuel for the production of 1 Gcal of heat.

FIG. 3 - Diagram of a method for optimizing the combustion of hydrocarbon fuel with an increase in the specific consumption of hydrocarbon fuel for the production of 1 Gcal of heat.

FIG. 4 - A schematic block diagram of a method for optimizing the combustion of hydrocarbon fuel in a boiler, implemented in industry in the Kichui boiler house.

In the schematic block diagrams shown in FIG. 1 and FIG. 4 introduced the following designations:

1 - boiler;

2 - fuel supply control device;

3 - fuel consumption meter;

4 - air flow regulator;

5 - coolant temperature sensor at the inlet to the heat exchanger;

6 - temperature sensor of the coolant at the outlet of the heat exchanger;

7 - coolant flow sensor;

8 - heat meter for determining the amount of heat;

9 - personal computer with a special program installed.

The inventive method is carried out as follows.

In a method for optimizing the combustion of hydrocarbon fuel in a boiler, associated petroleum gas of variable composition can be used as fuel, and atmospheric air can be used as an oxidizer.

Before starting the implementation of the proposed method for optimizing the combustion process of hydrocarbon fuel, the boiler 1 is brought to the power specified by the consumer in accordance with the regime map of the boiler.

After the combustion process has begun and the required amount of heat is supplied to the consumer, with a constant initially set fuel supply, at the command of the computer 9, the air flow controller 4 produces a one-time discrete increase in the air flow.

Further, according to the measured values of the temperature of the coolant at the inlet of the boiler 1 using the sensor 5 and at the outlet of the boiler 1 using the sensor 6, as well as the values of the mass of the passing coolant measured by the sensor 7, the heat meter 8 determines the deviation of the heat flux reported to the coolant from the initially set values.

Thus, the primary one-time discrete increase in the air flow rate makes it possible to estimate the tendency for the heat flow value to change relative to the initially set value, i.e. allows you to determine the point from which the regulation process begins (Point 1 in Fig. 2 and Fig. 3).

Then, depending on the change (increase or decrease) in the magnitude of the heat flux, actions are taken to ensure the optimal mode of fuel combustion with the achievement of the minimum specific fuel consumption per unit of heat flux.

In this case, two options for changing the combustion process are possible.

If, after a one-time discrete increase in air flow, there is a decrease in the specific consumption of hydrocarbon fuel for the production of 1 Gcal of heat, computer 9 issues a command to the air flow regulator 4 to increase the air flow step by step (Point 2 in Fig. 2), and each time after another increase in flow air, the computer 9 calculates the specific fuel consumption and compares its change with the previous value.

The process of increasing the air consumption occurs until the computer 9 detects the beginning of the increase in the specific fuel consumption (Point 3 of Fig. 2).

At this moment, from the computer 9, the air flow regulator 4 receives a command to stop the increase in the amount of supplied air, and then a command to decrease the amount of supplied air by one step (Point 4 in Fig. 2). Point 4 will be the point of the optimal fuel-air ratio at a given time when the maximum heating capacity of the boiler is reached with a given amount of fuel consumed and the minimum specific consumption of hydrocarbon fuel for the generation of 1 Gcal of heat.

In the event that, after a one-time discrete increase in the air flow rate, an increase in the specific consumption of hydrocarbon fuel for the production of 1 Gcal of heat occurs (Point 2 of Fig. 3), a command is sent from the computer 9 to the air flow controller 4 to stop the increase in the air supply and then the command to decrease the amount of supplied air. In this case, the computer 9 each time calculates the specific fuel consumption and compares its change with the previous value.

This process will continue until the specific fuel consumption starts to increase. At this moment, the computer issues the air flow regulator 4 (point 3 of Fig. 3) a command to stop the decrease in the amount of air and increase the air by one step, that is, to return to the point of optimal fuel-air ratio (point 4 of Fig. 3).

Further operation of the fuel-burning device is carried out taking into account the optimal ratio of fuel and air consumption determined as a result of the above actions (optimization of the combustion process), and with any changes in the value of the heat flow reported to the coolant, and, accordingly, changes in the specific fuel consumption for the production of 1 Gcal of heat, the process fuel combustion optimization is repeated.

Optimization of the combustion process of hydrocarbon fuel according to the claimed method can be carried out both in automatic and manual mode with the help of an operator.

After the implementation of the method for optimizing the combustion of hydrocarbon fuel in the boiler, it may be necessary to adjust the heat flux of the heat carrier to achieve the value required by the consumer.

So, with an increase in the value of the heat flow above the value required by the consumer, at the command of the computer 9, the fuel supply control device 2 first reduces the fuel consumption to the value of the heat flow in the coolant required by the consumer, after which the air flow controller 4 reduces the air consumption until the start of the decrease in the heat flow.

Accordingly, with a decrease in the heat flow value required by the consumer, at the command of the computer 9, the fuel supply control device 2 first increases the fuel consumption to generate the heat flow value required by the consumer in the coolant, after which the air flow controller 4 increases the air flow rate until the increase in the heat flow value stops. In this case, the air supply is adjusted without measuring its amount, i.e. without measuring the absolute value of the air flow.

After reaching the optimal fuel combustion mode, boiler 1 continues to operate at the set amount of supplied fuel and air until the next change in the specific fuel consumption occurs, indicating that there have been changes in external conditions.

An example of the implementation of the method.

The method for optimizing the combustion process of hydrocarbon fuel is implemented on boiler 1 (Fig. 4) DE 10-14 (enterprise of OAO TATNEFT, Kichui).

First, boiler 1 (Fig. 4) is fired up and brought to the required mode according to the boiler mode map, in which the ratio of fuel and air is prescribed in various modes of boiler operation.

After bringing the boiler 1 to the required power, a method for optimizing the combustion of hydrocarbon fuel is started. To do this, at the command of the computer 9, the air flow regulator 4 produces a one-time discrete increase in the air flow in the range from 0.01% to 2% of the total volume of the supplied air (while the fuel supply remains constant).

Further, the heat meter 8 (KrokhneVHV 310), using sensors 5, 6 and 7, installed to measure the temperature values of the coolant at the inlet of the boiler 1, at the outlet of the boiler 1 and determine the mass of the passing coolant, respectively, determines the current value of the heat flux reported to the coolant. This amount of heat flux is transferred to the computer 9.

Then, in the event that, after a one-time discrete increase in the air flow rate, the heat flow value increased from the initial set value, a discrete increase in the air flow rate is carried out using the air supply regulator 4 (Houndai N300R110NF) at the command of the computer 9, until the heat flow value decreases ... And vice versa, if the value of the heat flux has decreased from the initially set value, then a discrete decrease in the air consumption is carried out, using the air supply regulator 4 at the command of the computer 9, until the heat flux increases.

Computer 9 sends an appropriate command to the air flow regulator 4 based on the calculation of the specific consumption of hydrocarbon fuel for the production of a unit of heat (1 Gcal) reported to the coolant and comparing this value with the previous calculation (every 3 seconds). Thus, the optimum fuel-air ratio is determined.

After the implementation of the method for optimizing the combustion of hydrocarbon fuel in the boiler, it may be necessary to adjust the heat flux of the heat carrier to achieve the value required by the consumer.

In this case, with an increase in the heat flux above the value required by the consumer, at the command of the computer 9, the fuel supply regulator 2 first reduces the fuel consumption to the value of the heat flux in the coolant required by the consumer, after which the air flow controller 4 reduces the air consumption until the start of the decrease heat flux values.

Accordingly, with a decrease in the heat flow value required by the consumer, at the command of the computer 9, the fuel supply control device 2 first increases the fuel consumption to generate the heat flow value required by the consumer in the coolant, after which the air flow controller 4 increases the air flow rate until the increase in the heat flow value stops. In this case, the air supply is adjusted without measuring its amount, i.e. without measuring the absolute value of the air flow.

The value of the fuel consumption is measured by the fuel consumption meter 3 (gas meter SG-800) and entered into the computer memory 9.

The tests carried out showed that the application in the industry of the claimed technical solution provided:

- reduction in the consumption of hydrocarbon fuel by 7% when burning network gas, and 30% when burning associated petroleum gas with refinery waste, depending on the supply of a particular fuel composition;

- increasing the completeness of fuel combustion (no soot formation and underburning of fuel in boilers),

- reducing the labor intensity of the process of optimizing fuel combustion by reducing the number of measurements and, accordingly, reducing the number of instrumentation and auxiliary equipment used.

A significant reduction in the number of operations reduces the labor intensity of optimization, simplifies the optimization process, increases the efficiency of fuel use (minimizes fuel consumption), and expands the field of application of fuel combustion devices for thermal utilization of industrial waste.

The process of optimizing fuel combustion is carried out continuously throughout the entire operation of the boiler. The inventive method ensures the operation of the boiler in the optimal mode with minimal environmental damage, since there is complete combustion of the fuel.

The claimed technical solution is feasible when operating fuel-burning devices using gaseous, liquid and solid fuels. The method is feasible using publicly available measurement and automation tools, personal computers.

A significant difference of the proposed technical solution from the known ones is that the indicators of optimization of the combustion process are not the efficiency of the boiler and not the temperature of the coolant at the outlet of the boiler, but the ratio of the amount of fuel consumption to the amount of heat flow in the coolant at the outlet of the boiler, that is, the specific fuel consumption per generation of 1 Gcal of heat.

The method proposed for patenting is simple and reliable in use, adapts to any existing systems, is based on simple and reliable devices of domestic production, is not affected by the state of boilers, the state of air ducts, the state of chimneys and burners, it allows you to regulate the combustion of each burner in multi-burner boilers ... Moreover, in automatic mode, it provides the values of the heat flux of the heat carrier (steam or hot water) specified by the consumer.

Claims (3)

1. A method for optimizing the combustion of hydrocarbon fuel in a boiler, including continuous measurement of the fuel consumption in the boiler and the amount of heat flow in the coolant at the outlet of the boiler, determination of deviations of the measured values from the previous values and the subsequent change in air consumption depending on the increase or decrease in the heat flow, characterized in that, based on the measured values, the specific fuel consumption for the generation of 1 Gcal of heat is determined, calculating the ratio of the amount of fuel consumption to the value of the heat flow in the coolant at the outlet of the boiler, while at the beginning of the optimization of the fuel combustion process, a one-time discrete increase in the air consumption is performed to determine tendencies of the change in the value of the heat flux in the coolant in the direction of increase or decrease, while in order to obtain the optimal fuel-air ratio with an increase in the value of the heat flux, the air continues to increase until the beginning of the decrease in the heat flux, n With a decrease in the magnitude of the heat flux, the air is reduced until the beginning of the decrease in the heat flux. 2. A method for optimizing the combustion process of hydrocarbon fuel in a boiler according to claim 1 of the claims, characterized in that when the heat flux increases above the value required by the consumer, the fuel consumption for generating the heat flux required by the consumer in the coolant is reduced and then the air consumption is reduced until the start a decrease in the heat flux, and with a decrease in the heat flux below the value required by the consumer, the fuel consumption is increased to generate the heat flux required by the consumer in the coolant and then the air consumption is increased until the growth of the heat flux stops and the heat flux required by the consumer is reached. 3. A method for optimizing the combustion of hydrocarbon fuel in a boiler according to claim 1 of the claims, characterized in that when the value of the heat flux imparted to the heat carrier changes, the process of optimizing fuel combustion is repeated.

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