JP2005226954A - Fuel oil heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel oil heating device for heating fuel oil to a temperature suitable for combustion to supply the fuel oil at the constant temperature while suppressing the power consumption of a line heater to a required minimum when heating to supply the fuel oil. <P>SOLUTION: This fuel oil heating device is provided with a fuel oil temperature controller 16 having a function of changing at least two kinds of heating set temperatures according to the temperature detected by a steam temperature sensor 15, driving the line heater 4 on and off in relation to the detected temperature of a fuel oil temperature sensor 14, outputting signals allocated from 0% to 100% to the set temperature, to a flow regulating valve 13 to perform heating control of the fuel oil in fuel oil supply piping 25 with steam supplied by proportional opening/closing to a heat exchanger 5. During the steady operation of a boiler 23, fuel oil heating control mainly based on the heat exchanger 5 is performed to supply the fuel oil at the constant temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a fuel oil heating apparatus for heating fuel oil supplied to a burner of a steam boiler to a predetermined temperature and supplying the fuel oil at a constant temperature suitable for combustion.

When supplying highly viscous fuel oil to the burner of a steam boiler, the conventional method is to install a line heater that heats the fuel oil supply pipe with electric power and a heat exchanger that heats with the steam of its own boiler. The fuel oil supply pipe that exits from the oil tank is made into a circulation circuit that passes through the oil pump, the line heater, and the heat exchanger and returns to the fuel oil tank from the combustion nozzle inlet. The fuel oil is supplied using these line heater and heat exchanger. There is a fuel oil heating device that heats and supplies the fuel to a predetermined temperature.

At the start of boiler operation, the fuel oil is not heated to a predetermined temperature, and no steam is generated in the boiler. Therefore, the heat exchanger cannot be used, so the fuel oil is heated by the line heater. It will be.

At this time, when the fuel oil is heated up to a predetermined temperature only by passing through the line heater once, the boiler can shift to the combustion state immediately after the start of operation, but if the fuel oil is not heated up to the predetermined temperature unless it passes a plurality of times, the fuel Since the oil circulates to the fuel oil tank again, the boiler cannot move to the combustion state unless all the fuel oil in the fuel oil tank is heated, and much time is required from the start of operation to combustion. .

When the fuel oil is not heated by the heat exchanger for some reason during operation of the boiler, or is insufficient, the line heater heats the fuel oil to a predetermined temperature in order to supplement the capacity of the heat exchanger. As described above, when the line heater performs a heating operation, power is consumed. From the viewpoint of reducing running costs, it is desirable to minimize the power consumption of this line heater.

Also, if the line heater is installed upstream and the heat exchanger is installed downstream in the fuel oil supply pipe, and the fuel oil supply pipe from the line heater outlet to the heat exchanger inlet has a distance, the boiler In such a case, the fuel oil heated by the line heater causes a temperature drop due to heat radiation while passing through the fuel oil supply piping from the line heater outlet to the heat exchanger inlet and the heat exchanger to which no steam is supplied. Therefore, it is necessary to set the temperature of the fuel oil temperature controller in consideration of this temperature drop. Here, when the line heater outlet is very close to the heat exchanger inlet, and the heat dissipation of the heated fuel oil passing through the fuel oil supply pipe between them is negligible, the line heater It is not necessary to consider the temperature drop due to heat radiation of the fuel oil supply pipe from the outlet to the heat exchanger inlet.

When steam is generated by the boiler and steam is supplied to the heat exchanger, it is heated by the heat exchanger, so it is necessary to heat the fuel oil to a set temperature that takes into account the temperature drop after heating with the line heater. Disappear. Therefore, if the temperature set value can be changed according to these different states, such as before and after steam generation in the boiler, the power consumption of the line heater can be minimized.

When fuel oil is heated by a heat exchanger, the temperature drop due to heat dissipation upstream of the heat exchanger in the fuel oil supply pipe need not be considered, and the fuel oil supply pipe from the heat exchanger to the burner As for the temperature drop of this part, the temperature drop in this part is the same condition as the heating by the line heater and the heating by the heat exchanger, and therefore, the description is omitted here.

In addition, it is known that the oils and moisture contained in fuel oil generally expand in volume, that is, decrease in density when the temperature rises. Therefore, when fuel oil is supplied using a constant volume transfer type fuel pump per unit time, the combustion amount per unit time decreases as the temperature of the fuel oil rises. At this time, the combustion blower ( If the amount of air is not limited to the heating temperature of the fuel oil but is constant, combustion due to relative excess air is performed. When the oil temperature is lowered, the density increases and combustion occurs in an air-deficient state. At the same time, the viscosity of the fuel oil also increases, resulting in a problem in the supply of the fuel oil. For this reason, the fuel oil is required to be supplied at a constant temperature with respect to a predetermined temperature.
Japanese Utility Model Publication No. 4-108143

It is an object of the present invention to provide a control method capable of heating a fuel oil to a predetermined temperature and supplying the fuel oil at a constant temperature while suppressing power consumption of the line heater to a necessary minimum in the fuel oil heating apparatus in the background art. And

In order to solve the above-described problems, the invention according to claim 1 is directed to a line heater (4) and a boiler for heating fuel oil pumped by the oil pump (3) with fuel in the fuel oil supply pipe (25). Fuel oil heating for supplying a part of the steam sent out from (23) to the burner part (11) of the boiler (23) via the heat exchanger (5) supplied and heated by the fuel oil heating steam pipe (19) In the apparatus, at least the fuel oil supplied to the burner section (11) is supplied to the oil pump (3) until the fuel oil supply pipe (25) rises to a first predetermined temperature suitable for combustion. The fuel oil temperature sensor (14) is formed on the outlet side of the heat exchanger (5) of the fuel oil supply pipe (25), and is connected to the boiler (23) or the fuel oil heating steam pipe. (19) measure the steam temperature The steam temperature sensor (15) is provided with a flow rate adjusting valve (13) for adjusting the steam flow rate in the fuel oil heating steam pipe (19), and the fuel oil supply pipe before the start of the boiler (23). The fuel oil temperature rises to the first predetermined temperature until the fuel oil temperature sensor (14) detects that the temperature of the fuel oil circulating in (25) first rises to the first predetermined temperature. When the temperature sensor (14) detects that the fuel oil is heated only by the line heater (4) which is stopped driving, the fuel oil temperature sensor (14) indicates that the temperature of the fuel oil has first risen to the first predetermined temperature. ) Is detected, the burner section (11) is driven to a continuous operation state, and the fuel oil temperature sensor indicates that the temperature of the fuel oil has decreased by a specific temperature from the first predetermined temperature until the steam temperature becomes equal to or higher than the specified temperature. (14) When detected, the line heater (4) is re-driven, the fuel oil is heated only by the line heater (4), and when the steam temperature sensor (15) detects that the steam temperature has exceeded the specified temperature, the temperature of the fuel oil burns However, the flow rate adjustment valve (13) is operated so that the second predetermined temperature is lower than the first predetermined temperature, and the fuel oil is heated only by the heat exchanger (5). When the fuel oil temperature sensor (14) detects that the fuel oil temperature sensor (14) has decreased by a specific temperature from the predetermined temperature, the fuel oil temperature is controlled so that the line heater (4) is restarted and the line heater (4) is stopped when the second predetermined temperature is reached A fuel oil heating device provided with a controller (16).

When the fuel oil temperature sensor (14) detects that the fuel oil temperature has dropped below the limit temperature in the fuel oil heating device according to claim 1, the fuel oil temperature controller (14) 16) performs control to stop the supply of fuel oil to the burner section (11).

According to a third aspect of the present invention, in the fuel oil heating device according to the first or second aspect, when the fuel oil first rises to a first predetermined temperature, the fuel that drives the burner section (11) to a continuous operation state. The control of the oil temperature controller (16) is based on a drive signal issued to the burner unit (11) when the fuel oil temperature sensor (14) detects that the temperature of the fuel oil first rises to the first predetermined temperature. It is control.

According to a fourth aspect of the present invention, in the fuel oil heating device according to the first or second aspect, when the temperature of the fuel oil first rises to a first predetermined temperature, the burner unit (11) is driven to a continuous operation state. When the fuel oil temperature sensor (14) detects that the temperature of the fuel oil first rises to the first predetermined temperature, the control of the fuel oil temperature controller (16) is supplied to the burner section (11). In order to raise the pressure of the fuel oil to the automatic injection pressure of the burner part (11), it is emitted to the first solenoid valve (7) provided in the circulation path from the burner part (11) of the fuel oil supply pipe (25). The control is based on a closing signal.

According to a fifth aspect of the present invention, in the fuel oil heating apparatus according to the first to fourth aspects, the fuel supplied to the burner section (11) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion. A fuel supply valve (26) interlocking with the oil pump (3) is provided upstream of the inlet of the circulation path of the fuel oil supply pipe (25), and at least the oil pump in the circulation path of the fuel oil supply pipe (25) The entry side of (3) is a vessel (1) for supplying fuel oil to an oil pump (3) for storing a predetermined amount of fuel oil.

According to the first aspect of the present invention, the fuel oil pressure-fed in the fuel oil supply pipe (25) by the oil pump (3) is sent out from the line heater (4) and the boiler (23) for heating with electric power. In the fuel oil heating apparatus for supplying a part of the steam to the burner part (11) of the boiler (23) through the heat exchanger (5) supplied and heated by the fuel oil heating steam pipe (19), the fuel oil supply The pipe (25) has a circulation path for returning the fuel oil supplied to the burner section (11) to at least the inlet side of the oil pump (3) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion. The fuel oil temperature sensor (14) is formed on the outlet side of the heat exchanger (5) of the fuel oil supply pipe (25), and the steam temperature is supplied to the boiler (23) or the fuel oil heating steam pipe (19). Steam temperature sensor to measure (15 However, the fuel oil heating steam pipe (19) is provided with a flow rate adjusting valve (13) for adjusting the steam flow rate, and circulates through the fuel oil supply pipe (25) before starting the boiler (23). The fuel oil temperature sensor (14) indicates that the temperature of the fuel oil has increased to the first predetermined temperature until the fuel oil temperature sensor (14) detects that the temperature of the fuel oil has first increased to the first predetermined temperature. When the fuel oil temperature sensor (14) detects that the fuel oil is heated only by the line heater (4), which is stopped when detected, and the temperature of the fuel oil first rises to the first predetermined temperature, the fuel oil is detected. When the fuel oil temperature sensor (14) detects that the temperature of the fuel oil has decreased by a specific temperature from the first predetermined temperature before the burner portion (11) is driven to a continuous operation state and the steam temperature becomes equal to or higher than the specified temperature. Rheinhe (4) is driven again, the fuel oil is heated only by the line heater (4), and when the steam temperature sensor (15) detects that the steam temperature has exceeded the specified temperature, the temperature of the fuel oil is suitable for combustion. However, the flow rate adjusting valve (13) is operated so that the second predetermined temperature is lower than the first predetermined temperature, and the fuel oil is heated only by the heat exchanger (5), and the temperature of the fuel oil is lower than the second predetermined temperature. When the fuel oil temperature sensor (14) detects that the temperature has decreased by a specific temperature, the fuel oil temperature controller (14) performs control to restart the line heater (4) and stop the line heater (4) when the second predetermined temperature is reached. 16), a highly viscous fuel oil can be supplied to the burner part (11) of the boiler (23) at a constant temperature suitable for combustion. Requires power consumption of heater (4) It can be minimized.

According to the invention of claim 2, in the fuel oil heating device of claim 1, when the fuel oil temperature sensor (14) detects that the fuel oil temperature has dropped below the limit temperature, the fuel oil temperature control By performing control that stops the supply of fuel oil to the burner section (11) by the vessel (16), combustion in an air-deficient state in the burner (21) can be prevented.

According to the invention described in claim 3, in the fuel oil heating apparatus according to claim 1 or 2, when the fuel oil first rises to the first predetermined temperature, the burner section (11) is driven to a continuous operation state. When the fuel oil temperature sensor (14) detects that the fuel oil temperature controller (16) detects that the temperature of the fuel oil has first increased to the first predetermined temperature, the drive is issued to the burner unit (11). By controlling with a signal, fuel oil suitable for combustion can be supplied to the burner part (11), and stable combustion can be performed in the burner (21).

According to the fourth aspect of the present invention, in the fuel oil heating device according to the first or second aspect, when the temperature of the fuel oil first rises to the first predetermined temperature, the burner unit (11) is continuously operated. Is supplied to the burner unit (11) when the fuel oil temperature sensor (14) detects that the temperature of the fuel oil first rises to the first predetermined temperature. The first solenoid valve (7) provided in the circulation path from the burner portion (11) of the fuel oil supply pipe (25) in order to increase the pressure of the fuel oil to be increased to the automatic injection pressure of the burner portion (11). Due to the control by the closed signal that is emitted, the fuel oil rises from the fuel oil heating state in which the fuel oil circulates in the fuel oil supply pipe (25) below the first predetermined temperature to the first predetermined temperature, and the fuel oil is burned. Efficient in continuous operation state supplied to (11) It is possible to Ku transition.

According to a fifth aspect of the present invention, in the fuel oil heating apparatus according to the first to fourth aspects, the fuel supplied to the burner section (11) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion. A fuel supply valve (26) interlocking with the oil pump (3) is provided upstream of the inlet of the circulation path of the fuel oil supply pipe (25), and at least the oil pump ( 3) The entry side of 3) is a vessel (1) for supplying fuel oil to an oil pump (3) for storing a predetermined amount of fuel oil, so that fuel oil is being heated or the boiler (23) is shut down. The volume expansion of the fuel oil generated in the fuel oil supply pipe (25) of the boiler (23) can be absorbed by the residual heat afterwards.

Hereinafter, embodiments of the fuel oil heating device of the present invention will be described in detail with reference to the drawings.

The fuel oil heating apparatus of the present invention shown in FIG. 1 includes a line heater (4) and a boiler (23 that heats the fuel oil pumped by the oil pump (3) through the fuel oil supply pipe (25) with electric power. In the fuel oil heating apparatus for supplying a part of the steam sent out from the fuel oil heating steam pipe (19) to the burner section (11) of the boiler (23) via the heat exchanger (5) for heating. The fuel oil supply pipe (25) returns at least the fuel oil supplied to the burner section (11) to the inlet side of the oil pump (3) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion. A fuel oil temperature sensor (14) is formed on the outlet side of the heat exchanger (5) of the fuel oil supply pipe (25), and is connected to the boiler (23) or the fuel oil heating steam pipe (19). Steam temperature sensor for measuring steam temperature The sensor (15) is provided with a flow rate adjusting valve (13) for adjusting the steam flow rate in the fuel oil heating steam pipe (19), and before the start of the boiler (23), the fuel oil supply pipe (25 The fuel oil temperature sensor indicates that the temperature of the fuel oil has increased to the first predetermined temperature until the fuel oil temperature sensor (14) detects that the temperature of the fuel oil circulating through the first gas temperature has increased to the first predetermined temperature. When the fuel oil is heated only by the line heater (4) whose driving is stopped when (14) is detected, the fuel oil temperature sensor (14) indicates that the temperature of the fuel oil first rises to the first predetermined temperature. When detected, the burner unit (11) is driven to a continuous operation state, and the fuel oil temperature sensor (14) indicates that the temperature of the fuel oil has decreased by a specific temperature from the first predetermined temperature before the steam temperature becomes equal to or higher than the specified temperature. When detected When the steam temperature sensor (15) detects that the steam temperature has exceeded the specified temperature by re-driving the heater (4) and heating the fuel oil only with the line heater (4), the temperature of the fuel oil is suitable for combustion. However, the flow rate adjusting valve (13) is operated so that the second predetermined temperature is lower than the first predetermined temperature, and the fuel oil is heated only by the heat exchanger (5), and the temperature of the fuel oil is lower than the second predetermined temperature. When the fuel oil temperature sensor (14) detects that the temperature has decreased by a specific temperature, the fuel oil temperature controller (14) performs control to restart the line heater (4) and stop the line heater (4) when the second predetermined temperature is reached. 16).

In the fuel oil heating apparatus, the boiler (23) has a structure for generating steam by the combustion heat of the burner (21). The generated steam is separated from the liquid component that could not be evaporated in the steam separator (22), passes through the main steam valve (12), and is supplied to the use destination of the steam. At this time, since the boiler (23) has a structure capable of generating steam at a pressure higher than atmospheric pressure, normally only steam at 100 ° C. can be obtained at atmospheric pressure. In this case, for example, in the boiler (23) When the absolute pressure is 0.2 MPa, steam at about 120 ° C. can be obtained.

The fuel oil temperature controller (16) is a device for setting the fuel oil heating temperature of the line heater (4) and the heat exchanger (5), and the steam of the boiler (23) detected by the steam temperature sensor (15). Is input to the fuel oil temperature controller (16) via the steam temperature detector (17), and two fuel oil heating set temperatures SP0, SP1 and VP0, VP1 are set according to the specified temperature of the steam. By switching, the drive signal to the line heater (4) is analyzed by the fuel oil heating temperature detected by the fuel oil temperature sensor (14), and the temperature change of the fuel oil detected by the fuel oil temperature sensor (14) is also analyzed. However, an operation signal to the flow rate adjusting valve (13) for supplying the steam of the boiler (23) to the heat exchanger (5) is transmitted to the heat exchanger (5) with a signal allocated from 0% to 100% with respect to the heating temperature of the fuel oil. Function that can With.

The line heater (4) is driven by a signal from the fuel oil temperature controller (16) according to the temperature of the fuel oil detected by the fuel oil temperature sensor (14). The heat exchanger (5) exchanges the heat of the steam generated in the boiler (23) with fuel oil, and also controls the temperature change of the fuel oil detected by the fuel oil temperature sensor (14). The flow rate control valve (13) is proportionally opened / closed by an operation signal transmitted by allocating from 0% to 100% with respect to the set heating temperature of the fuel oil while being analyzed by the vessel (16). The heating control of the fuel oil is performed by controlling the supply amount of the steam.

The flow rate control valve (13) heats the fuel oil by operating in the fully open state or the fully closed state so as to drive the line heater (4) according to the heating temperature of the fuel oil detected by the fuel oil temperature sensor (14). Although it is possible to perform control, it is possible to perform more stable fuel oil heating control with respect to the heating set temperature by the operation method as described above.

When the boiler (23) is started, the fuel oil pressure-fed through the fuel oil supply pipe (25) by the oil pump (3) is supplied to the first predetermined temperature by the line heater (4) and the heat exchanger (5). Until heated. When the heating temperature of the fuel oil detected by the fuel oil temperature sensor (14) is lower than the first predetermined temperature, the burner (21) does not enter the combustion operation and the fuel oil circulates through the fuel supply pipe (25). Heated to a predetermined temperature. When the fuel oil temperature sensor (14) detects that the fuel oil has been heated to the first predetermined temperature or higher, a drive signal is issued from the fuel oil temperature controller (16) to the burner (21), and the combustion operation is started. Transition. When the burner (21) shifts to the combustion operation, a closing signal is transmitted from the fuel oil temperature controller (16) to the first electromagnetic valve (7), thereby closing the first electromagnetic valve (7). The fuel oil circuit in the burner section (11) is switched from the circulation path side to the combustion side by the fuel hydraulic pressure feed pressure of the oil pump (3), and the fuel oil heated from the low combustion side nozzle (9) is sprayed and burner ( The low combustion is performed by the ignition operation of 21). Then, if more steam is required due to an increase in the load at the place where the steam is used, an open signal is transmitted from the fuel oil temperature controller (16) to the second solenoid valve (8). The solenoid valve (8) is opened, fuel oil is sprayed from the high combustion side nozzle (10), and high combustion is performed.

What is described in the present embodiment is a fuel oil supply circuit whose combustion method is “stop-low combustion-high combustion”, but if a circulation path for heating the fuel oil as described above is formed. The same effect can be obtained even in a fuel oil circuit whose combustion mode is “stop-combustion”.

FIG. 3 shows that when steam temperature generated by the boiler (23) and detected by the steam temperature sensor (15) is TV and the specified temperature is 100 ° C., (A) shows that the steam temperature TV is less than 100 ° C. (I) is the proportionality of the flow rate control valve (13) to the driving condition of the line heater (4) when the steam temperature TV is 100 ° C. or higher and the fuel oil heating temperature detected by the fuel oil temperature sensor (14). The steam supply ratio to the heat exchanger (5) by opening and closing is shown. Then, the steam of the boiler (23), which is detected by the steam temperature sensor (15), is switched from the two fuel oil heating set temperatures SP0 to SP1 and VP0 to VP1 or vice versa (a) and (b). The fuel oil temperature controller (16) receives a signal output from the steam temperature detector (17) due to the temperature change.

In this embodiment, in consideration of the temperature drop after heating the fuel oil as described above, the set temperatures of the line heater (4), combustion limit, and heat exchanger (5) of the fuel oil temperature controller (16) are boilers. The steam temperature TV generated at (23) and detected by the steam temperature sensor (15) is set to be higher by 10 ° C. when the steam temperature TV is lower than 100 ° C., when the steam temperature TV is lower than 100 ° C.

Combustion restriction is an operation of stopping and waiting for burner combustion when the temperature of the fuel oil is assumed to affect the steady combustion of the burner.

Here, the specified temperature of the steam is 100 ° C. is an example. The specified temperature can be determined by the capacity of the heat exchanger (5). In other words, the heat exchanger (5) can be selected so that the steam and the fuel oil can exchange heat even if the specified temperature is not excessively high.

For example, in the case of saturated steam, the retained latent heat at a steam temperature of 100 ° C. is about 2256 kJ / kg, but the retained latent heat at 150 ° C. is about 2113 kJ / kg, and as the steam temperature increases, the per unit mass Since the retained latent heat decreases, it can be seen that if the steam temperature is high, the efficiency is not always good, and a large amount of steam is required for heat exchange. For this reason, the specified temperature of the steam does not need to be set too high.

In the present invention, the line heater (4) of the fuel oil temperature controller (16) and the heat exchanger (5) are generated with the steam temperature generated by the boiler (23) and detected by the steam temperature sensor (15) as a specified temperature. However, in this case, the steam pressure generated in the boiler (23) is used instead of the steam temperature as the fuel instead of the steam temperature. You may use for the parameter of the setting temperature switching with respect to the line heater (4) and heat exchanger (5) of an oil temperature controller (16).

For example, when the steam temperature is 100 ° C., the steam pressure is about 0.101 MPa, and when it is 150 ° C., it is about 0.476 MPa.

As shown in FIG. 3A, the boiler detected by the steam temperature sensor (15) at the start of the boiler (23) in a state where steam is not generated in the boiler (23) such as a cold start. When the temperature of the steam generated in (23) is less than 100 ° C., the fuel oil heating control is mainly performed by the line heater (4). According to this figure, the heating set temperature VP0 of the heat exchanger (5) is set higher than the heating set temperature SP0 of the line heater (4). However, since the steam temperature is actually less than 100 ° C., at this time It may be considered that the fuel oil is not heated in the heat exchanger (5). Therefore, the fuel oil is heated to the temperature of SP0 by the line heater (4). This temperature corresponds to the first predetermined temperature.

When the temperature of the steam generated in the boiler (23) detected by the steam temperature sensor (15) becomes 100 ° C. or higher as shown in FIG. 3 (a), the output is made via the steam temperature detector (17). The set temperature of the fuel oil is switched by the fuel oil temperature controller (16) based on the signal, and the control proceeds to the fuel oil heating control mainly of the heat exchanger (5). At this time, the fuel oil heating set temperature SP1 of the line heater (4) is set to be lower than that in FIG. 3 (a). This is for giving priority to the heating capacity of the heat exchanger (5). This is because the fuel oil heating control of the heat exchanger (5) with the proportional flow rate can be performed more stably than the fuel oil heating control by ON-OFF driving of the line heater (4). At this time, the fuel oil is heated to the temperature of VP1. This temperature corresponds to the second predetermined temperature.

As in this embodiment, when the predetermined temperature of the fuel oil is set to 90 ° C. and supplied to the burner (21) of the boiler (23), no steam is generated in the boiler (23) such as a cold start. When the temperature of the steam generated in the boiler (23) detected by the steam temperature sensor (15) at the start of the boiler (23) is less than 100 ° C, the fuel oil temperature detected by the fuel oil temperature sensor (14) The fuel oil supply pipe from the line heater outlet to the heat exchanger inlet and the steam are not supplied to the predetermined temperature of the fuel oil only by the fuel oil heating control by driving the line heater (4) on and off according to the temperature. The fuel oil must be heated in consideration of the temperature drop due to heat dissipation while passing through the heat exchanger, but the steam temperature TV generated by the boiler (23) and detected by the steam temperature sensor (15) is 1. When the temperature is 0 ° C. or higher, the fuel oil temperature controller (16) analyzes the change in the temperature of the fuel oil detected by the fuel oil temperature sensor (14) by using the heat exchanger (5). The flow rate control valve (13) is proportionally opened / closed by an operation signal transmitted by allocating from 0% to 100% with respect to the heating set temperature of the fuel, and stable fuel oil is obtained by controlling the amount of steam supplied based on the degree of opening / closing. Can be controlled.

Here, since the predetermined temperature of the fuel oil is 90 ° C., SP0 is set to 90 ° C. even when the steam temperature TV as shown in FIG. SP0 is set to 95 ° C. because the temperature drop due to heat radiation while passing through the fuel oil supply pipe to the heat exchanger inlet and the heat exchanger not supplied with steam is taken into account at 5 ° C.

When the steam temperature TV as shown in FIG. 3 (a) is 100 ° C. or higher, the line heater (4) is driven from the fuel oil temperature detected by the fuel oil temperature sensor (14) from 90 ° C. to 84 ° C. Although it is a case where it falls, since it is designed so that the fuel oil can be heated to 90 ° C. by the heat exchanger (5) if the steam temperature TV can be secured at 100 ° C. or higher, the boiler (23) During steady operation, the fuel oil heating control of the heat exchanger (5) can be performed. Therefore, with the fuel oil heating device, the line heater (4) can be handled as an auxiliary role of the heat exchanger (5) during operation of the boiler (23), and power consumption can be minimized. it can.

In the present invention, the predetermined temperature of the fuel oil is set to 90 ° C., but in experiments conducted by the present inventors for determining the predetermined temperature suitable for the combustion of the fuel oil, the temperature of the fuel oil is about 120 ° C. or higher or about 70 ° C. or lower. In such a situation, due to excess air combustion due to a decrease in the density of the fuel oil or air deficiency combustion due to an increase in density and an increase in the viscosity of the fuel oil, vibration combustion in the burner (21) and generation of soot in the combustion exhaust gas Abnormal combustion was confirmed.

Accordingly, in the present invention, in order to prevent the fuel oil from being supplied to the burner (23) when the fuel oil is not sufficiently heated for some reason, the steam temperature TV is less than 100 ° C. as a combustion limit. When the fuel oil temperature detected by the fuel oil temperature sensor (14) is 80 ° C. or lower, the fuel oil temperature is 70 ° C. or lower when the steam temperature TV is 100 ° C. or higher. The controller (16) performs control to stop the supply of fuel oil to the burner section (11) to stop and wait for the combustion of the burner (21). The set temperature for stopping the fuel oil supply corresponds to the limit temperature. Further, the fuel oil temperature for combustion restriction is set when the temperature drops by 10 ° C. with respect to SP0 and SP1, respectively, and this 10 ° C. corresponds to the specific temperature.

In addition, when the fuel oil as in the present invention is heated to about 90 ° C., when the fuel oil is heated with a liquid using a heating device such as the heat exchanger (5), the heat to be exchanged is only sensible heat. Therefore, in the case of hot water, it is necessary to increase the heat transfer area to obtain a large amount of exchange heat, or to use a liquid that can be heated to a high temperature, such as heat transfer oil. On the other hand, when fuel oil is heated by steam, since the retained latent heat of steam can be used as described above, if a heat exchanger (5) that can exchange heat with saturated steam is selected, superheated steam is used. Even if not, the fuel oil can be heated more easily than the liquid.

For these reasons, the fuel oil heating device of the present invention is used in a steam boiler, and the predetermined temperature of the fuel oil is 90 ° C. in this embodiment.

The fuel oil heating apparatus of the present invention shown in FIG. 2 is a burner section (11) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion in the fuel oil heating apparatus of the present invention shown in FIG. ) Is provided upstream of the inlet of the circulation path of the fuel oil supply pipe (25), and at least the oil pump (3) in the circulation path of the fuel oil supply pipe (25). A vessel (1) for supplying fuel oil to an oil pump (3) for storing a predetermined amount of fuel oil is provided on the inlet side.

For example, when the boiler (23) is stopped due to the difference in height between the installation position of the boiler (23) and the installation position of the fuel oil tank (not shown), the fuel oil in the fuel oil tank passes through the fuel oil supply pipe (25). A fuel supply valve (26) interlocking with the oil pump (3) may be provided upstream of the inlet of the circulation path of the fuel oil supply pipe (25) in order to prevent passage and supply to the burner (21). Conceivable.

When the boiler (23) stops after normal operation, the fuel oil supply pipe (25) becomes a closed circulation path because the fuel supply valve (26) is closed. The fuel oil in the fuel oil supply pipe (25) leaks from the joint of the fuel oil supply pipe (25) due to volume expansion due to the residual heat of the boiler (23) itself and its surroundings after the boiler (23) stops. There is also a risk that it may occur or, similarly, leak from the low combustion side nozzle (9) and the high combustion side nozzle (10) into the boiler (23) and cause an explosion when the burner (21) is ignited next time. In order to prevent these accidents, the vessel (1) is provided at least on the inlet side of the oil pump (3) in the circulation path of the fuel oil supply pipe (25). The vessel (1) has a structure capable of absorbing the volume expansion of the fuel oil generated by the boiler (23) itself after stopping the boiler (23) and the residual heat in the vicinity thereof.

In the fuel oil heating apparatus of the present embodiment, the fuel oil heating control similar to that of the fuel oil heating apparatus of the first embodiment is performed, so that the boiler (23) is in steady operation except during a cold start, and the heat exchanger (5) The main fuel oil heating control is possible. Therefore, with the fuel oil heating device, the line heater (4) can be handled as an auxiliary role of the heat exchanger (5) during operation of the boiler (23), and power consumption can be minimized. it can.

It is explanatory drawing which showed Example 1 of the fuel oil heating apparatus which concerns on this invention. It is explanatory drawing which showed Example 2 of the fuel oil heating apparatus which concerns on this invention. Fuel oil detected by the fuel oil temperature sensor (14) when the steam temperature of the boiler (23) detected by the steam temperature sensor (15) is lower than the specified temperature (A) and when the steam temperature is higher than the specified temperature (I) It is explanatory drawing showing the drive state and combustion restriction | limiting of a line heater (4) or a heat exchanger (5) with respect to the fuel oil temperature in supply piping (25).

Explanation of symbols

1 Vessel 2 Check Valve 3 Oil Pump 4 Line Heater 5 Heat Exchanger 6 Steam Trap 7 First Electromagnetic Valve 8 Second Electromagnetic Valve 9 Low Combustion Side Nozzle 10 High Combustion Side Nozzle 11 Burner 12 Main Steam Valve 13 Flow Control Valve 14 Fuel oil temperature sensor 15 Steam temperature sensor 16 Fuel oil temperature controller 17 Steam temperature detector 18 Main steam pipe 19 Fuel oil heating steam pipe 20 Wind box 21 Burner 22 Steam / water separator 23 Boiler 24 Line 25 Fuel oil supply pipe 26 Fuel supply valve TV Steam temperature SP0 of the boiler (23) detected by the steam temperature sensor (15) Fuel oil heating set temperature SP1 when the TV is less than the specified temperature SP1 By the line heater when the TV is equal to or higher than the specified temperature Fuel oil heating set temperature VP0 Fuel oil heating set temperature VP1 T by heat exchanger when TV is lower than specified temperature Fuel oil heating set temperature by heat exchanger when V is above specified temperature

Claims (5)

A part of the steam sent from the line heater (4) and the boiler (23) for heating the fuel oil pumped in the fuel oil supply pipe (25) by the oil pump (3) by the electric power and the fuel oil heating steam pipe ( 19) In the fuel oil heating device that supplies the heat to the burner section (11) of the boiler (23) through the heat exchanger (5) that is supplied and heated by the fuel oil supply pipe (25), the temperature of the fuel oil Is formed so as to have a circulation path for returning at least the fuel oil supplied to the burner section (11) to the inlet side of the oil pump (3) until the temperature rises to a first predetermined temperature suitable for combustion. A fuel oil temperature sensor (14) on the outlet side of the heat exchanger (5) of the supply pipe (25), and a steam temperature sensor for measuring the steam temperature in the boiler (23) or the fuel oil heating steam pipe (19) (15) is the fuel oil The thermal steam pipe (19) is provided with a flow rate adjusting valve (13) for adjusting the steam flow rate, and the fuel oil circulating through the fuel oil supply pipe (25) before starting the boiler (23) is provided. The fuel oil temperature sensor (14) indicates that the temperature of the fuel oil has increased to the first predetermined temperature until the fuel oil temperature sensor (14) detects that the temperature has first increased to the first predetermined temperature. When the fuel oil temperature sensor (14) detects that the fuel oil is heated only by the line heater (4), which is stopped when detected, and the temperature of the fuel oil first rises to the first predetermined temperature, the fuel oil is detected. The fuel oil temperature sensor (14) drives the burner part (11) to a continuous operation state, and the fuel oil temperature sensor (14) indicates that the temperature of the fuel oil has decreased by a specific temperature from the first predetermined temperature until the steam temperature becomes equal to or higher than the specified temperature. When detected, the line heat (4) is re-driven, the fuel oil is heated only by the line heater (4), and when the steam temperature sensor (15) detects that the steam temperature has exceeded the specified temperature, the temperature of the fuel oil is suitable for combustion. However, the flow rate adjusting valve (13) is operated so that the second predetermined temperature is lower than the first predetermined temperature, and the fuel oil is heated only by the heat exchanger (5). Control for stopping the line heater (4) when the fuel oil temperature sensor (14) detects that the temperature has decreased by a specific temperature from the second predetermined temperature and stopping the line heater (4) when the second predetermined temperature is reached. The fuel oil temperature controller (16) which performs is provided with the fuel oil heating apparatus characterized by the above-mentioned. When the fuel oil temperature sensor (14) detects that the fuel oil temperature has fallen below the limit temperature, the fuel oil temperature controller (16) performs control to stop the supply of the fuel oil to the burner section (11). Item 4. The fuel oil heating apparatus according to Item 1. When the fuel oil first rises to the first predetermined temperature, the control of the fuel oil temperature controller (16) that drives the burner unit (11) to the continuous operation state causes the temperature of the fuel oil to first rise to the first predetermined temperature. The fuel oil heating device according to claim 1 or 2, wherein the fuel oil temperature sensor (14) controls the operation by a drive signal issued to the burner section (11). When the temperature of the fuel oil first rises to the first predetermined temperature, the control of the fuel oil temperature controller (16) that drives the burner unit (11) to the continuous operation state is performed. When the fuel oil temperature sensor (14) detects that the fuel oil temperature has risen, the fuel oil is supplied to increase the pressure of the fuel oil supplied to the burner part (11) to the automatic injection pressure of the burner part (11). The fuel oil heating device according to claim 1 or 2, wherein the control is based on a closing signal issued to a first electromagnetic valve (7) provided in a circulation path from the burner portion (11) of the pipe (25). Interlocking with the oil pump (3) upstream of the circulation path of the fuel oil supply pipe (25) of the fuel oil supplied to the burner section (11) until the temperature of the fuel oil rises to a first predetermined temperature suitable for combustion A fuel supply valve (26) is provided, and at least an input side of the oil pump (3) in a circulation path of the fuel oil supply pipe (25) leads to an oil pump (3) for storing a predetermined amount of fuel oil. The fuel oil heating device according to any one of claims 1 to 4, which is a vessel (1) for supplying fuel oil.

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