KR19980077128A - Smokeless Hot Water Boiler with Waste Oil - Google Patents

Abstract

The present invention relates to a hot water boiler for agricultural horticulture such as a vinyl house, using a waste oil-free hot water boiler capable of fully automated operation at low operating cost due to high thermal efficiency without pollution pollution such as slag or soot.

The present invention forms a combustion chamber in the center and a boiler body having a hot water tank connected to the upper and lower boiler pipes disposed outside the combustion chamber, air supply means for blowing external air at a high pressure into the combustion chamber, and a waste oil tank; And a first refining means for refining water and foreign substances contained in the waste oil by using a specific gravity difference, a waste oil guide means for supplying the purified waste oil into the combustion chamber, and a high thermal conductivity material at a lower end of the combustion chamber. Ignition promoting means connected to the waste oil guiding means to promote ignition, preheating means connected to the lower end of the combustion chamber for preheating the inside of the combustion chamber for a predetermined time only during initial ignition, and installed in communication with the combustion chamber. Dust removal means for removing the dust contained in the exhaust gas to the above, After operating the preheating means for a predetermined time, the waste oil is introduced into the combustion chamber, and the combustion control means for blocking the introduction of the waste oil when the temperature of the hot water tank rises above the set temperature.

Description

Smokeless Hot Water Boiler with Waste Oil

The present invention relates to a smokeless hot water boiler using waste oil, in particular, a horticultural hot water boiler such as a plastic house, unleaded hot water using waste oil capable of fully automated operation at low operating costs due to high thermal efficiency without pollution pollution such as slag or soot It's about a boiler.

In general, farming vinyl house farming must maintain a constant indoor and underground temperature for four seasons of vegetables or horticulture, from autumn to winter to spring.

To this end, in the past, a briquette stove or a diesel boiler was installed to maintain a room temperature of the house at a temperature suitable for plant growth.

However, the method using the briquettes has to replace and maintain the briquettes with new briquettes at regular or unspecified times. Therefore, in the case of a large number of large houses, the management personnel and the management difficulties accordingly exist. In addition, there is a disadvantage that it is difficult for the user to maintain the temperature of the house to the desired set temperature.

On the other hand, the method using diesel has the disadvantage that the maintenance cost of operating the boiler is relatively high.

In view of such a problem of the prior art, Korean Utility Model Publication No. 90-1373 proposes a hot water boiler for waste oil combustion using waste oil which has a low fuel cost and causes pollution when it is discharged steplessly.

Referring to the hot water boiler in more detail with reference to Figure 1, the heating unit 2 is formed in the center of the boiler hot water tank 1, the upper end is connected to the chimney 17, the combustion chamber under the heating unit 2 (4) forming a combustion plate (5) having a waste oil diffusion plate (5A) in the combustion chamber (4) to open and close the waste oil through the oil guiding pipe (7) from the waste container (11). The volume is adjusted to the combustion plate 5, and the electric blower 6 is provided to the side of the combustion plate 5 to supply the combustion wind.

In Fig. 1, reference numeral 3 is a communication tube, 6A is a blower tube, 8 is an oil supply pipe, 10 is a connection hose, 12 is an opening and closing cock, 13 is a bucket, 14 is a water supply pipe, 15 is a water supply opening and closing cock, 16 is an expansion canister, 18 is Point out each of the draw filters.

By the way, in the conventional hot water boiler, since the direct ignition of waste oil having a high ignition point is directly fired at the time of initial ignition, ignition is difficult and thus combustion is performed at a low temperature, resulting in incomplete combustion, which causes a large amount of soot. The draw filter 18 can not filter the soot and harmful gas discharged to the outside has a problem that the soot is discharged in large quantities.

In addition, since the combustion temperature is low, slag, which is a pollution-inducing substance, is generated at the bottom of the combustion chamber after a long time of operation, and the supply amount of waste oil has to be manually adjusted according to the amount of combustion. Incomplete combustion may occur in the case, and conversely, when the supply amount of the waste oil is smaller than the combustion amount, there is a problem that the heat amount is low.

Therefore, the present invention has been made in view of the problems of the prior art, the purpose of which is a horticultural hot water boiler, such as a plastic house, can be fully automated operation at low operating costs due to high thermal efficiency without pollution pollution such as slag or soot To provide a smokeless hot water boiler using waste oil.

1 is a cross-sectional view showing the structure of a conventional waste oil hot water boiler,

Figure 2 is a cross-sectional view showing the entire structure of a smokeless hot water boiler using waste oil according to the present invention,

3 is a cross-sectional view showing the internal structure of the waste oil tank shown in FIG.

4 is a cross-sectional view showing the structure of the fuel filter shown in FIG.

5A and 5B are front enlarged and enlarged perspective views of the air injection pipe shown in FIG. 2;

6 is a control sequence diagram of the present invention hot water boiler shown in FIG.

Explanation of symbols on the main parts of the drawings

21: Oil burner (LB) 21A: Oil burner fan (BF)

22: switch 23: solenoid for the switch (S1)

24: combustion chamber 25: blower (FAN)

26: air injection pipe 26A: air injection port

27: fire plate 28: communication

29: solenoid valve (S2) 30: oil valve

31: copper coil 32: oil supply pipe

33: heat insulating material 34A, 34B: water spray nozzle

35 filter for removing impurities 36 air cleaner

37: drag removal device 38: water tank

39: water circulation pump 40: oxygen supply pipe

41 waste oil tank 41A, 41B: first and second refined plates

42: fuel filtration device 42A / 42B: waste oil inlet / outlet

42C: Drainage device 43: Water supply tank

44: thermometer 45: pressure gauge

46: pressure stabilizer 47: control box

48: hot water circulation exit 49: hot water circulation exit

50: air hole 51: level gauge

52: waste oil inlet 53: main power switch

54 Ammeter 55 Voltmeter

56: blower timer (T1) 57: burner fan timer (T2)

58: temperature controller 59: power supply relay (R)

60: timer for oil burner (T3) 61: timer for fuel switch (T4)

70: boiler case 71: hot water tank

72: float 73: water supply valve

74: hot water pipe 75: water

76 waste oil 77 exit

78: flame inlet pipe 79: discharge pipe

80: collecting container 81: oil tank

82: bottom plate

In order to achieve the above object, the present invention forms a combustion chamber in the center and the boiler body having a hot water tank connected to the upper and lower boiler pipes arranged outside the combustion chamber, and for blowing the outside air at a high pressure into the combustion chamber An oil supply means, a waste oil tank storing waste oil to be combusted, first purifying means for purifying water and foreign substances contained in the waste oil by using a specific gravity difference, and waste oil purified from the waste oil tank through a purifying means Waste oil guide means for supplying the inside of the combustion chamber and a high heat conductive material at the lower end of the combustion chamber and connected to the waste oil guide means to guide the waste oil supplied therein to flow along it to promote ignition. Means and connected to the lower end of the combustion chamber so that the inside of the combustion chamber Preheating means for heating, dust removal means for removing dust contained in the exhaust gas in a double manner in communication with the upper end of the combustion chamber, and operating the preheating means for a predetermined time during initial ignition and then Lead-free hot water boiler using waste oil characterized in that the waste oil is introduced into the combustion chamber through the waste oil guide means, and the combustion control means for blocking the introduction of the waste oil when the temperature of the hot water tank rises above the set temperature. to provide.

In the present invention, it is preferable that the control means further operates the air supply means for a set time so that slag does not remain in the combustion chamber when the waste oil is blocked.

In addition, the preheating means is a petroleum burner, a flame induction pipe for guiding the flame of the petroleum burner into the combustion chamber, and a switch installed in the flame induction pipe is opened during the operation of the petroleum burner and closed after a set time after the end of operation The switch is driven in accordance with the operation of the solenoid valve on / off in accordance with the control signal of the control means to protect the burner from the high heat of the combustion chamber when the oil burner is inoperative.

On the other hand, the dust removing means is installed in a vertical portion extending in the downward direction is bent in two stages from the communication and connected to the first dust removing means for collecting dust discharged by the water spray method, and the rear end of the dust removing means It is preferably composed of an air cleaner for removing residual dust, the water used to collect the dust is preferably configured to be reused by the water circulation system with a built-in filter.

Furthermore, the present invention further includes an oxygen supply pipe connected to the dust removing means and the lower part of the combustion chamber to supply oxygen during initial ignition and recycle part of the exhaust gas during combustion to induce complete combustion. Prevents incomplete combustion during boiler operation.

On the other hand, the air supply means to inject the external air while forming a vortex from the vertical end located in the combustion chamber to ensure a smooth oxygen supply during the combustion of the fuel.

The ignition promoting means is made of a helical copper copper wire, and serves as a catalyst to easily ignite when the waste oil flows down in a preheated state at a high temperature.

The waste oil tank further includes second refining means for refining water and foreign matter contained in the waste oil by using a specific gravity difference, and heating means for increasing fluidity of the waste oil, wherein the refining means has a plurality of sequential heights. It is formed into a tablet plate that is lowered.

As described above, in the present invention, the preheating structure using the petroleum burner suppresses the occurrence of dragging during the initial ignition of the waste oil, and induces complete combustion and zero slag by the vortex forming air injection pipe and the high-conductivity copper coil. In addition, the exhaust gas recirculation structure returns a part of the incomplete combustion gas to the combustion chamber, and at the same time, the exhaust gas is blocked by the particulate spray system using a water spray device and an air cleaner. Savings.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 is a cross-sectional view showing the entire structure of the unleaded hot water boiler using the waste oil according to the present invention, Figure 3 is a cross-sectional view showing the internal structure of the waste oil tank shown in Figure 2, Figure 4 is a fuel filtration device shown in Figure 2 5A and 5B are front enlarged and enlarged perspective views of the air injection pipe shown in FIG. 2, and FIG. 6 is a control sequence diagram of the hot water boiler of the present invention shown in FIG.

First, referring to FIG. 2, the unleaded hot water boiler using waste oil according to the present invention has a combustion chamber 24A formed therein by a cylindrical combustion cylinder 24, and a hot water tank 71 for heat exchange outside the combustion cylinder 24. ), A boiler case 70 is formed.

The boiler case 70 is formed of inner / outer cases 70A and 70B, and is filled with a heat insulating material 33 which can be used, for example, asbestos, in between.

The upper portion of the hot water tank 71 is connected through a pipe with a water supply tank 23 of a well-known structure in which a level sensing float 72 is installed therein so as to constantly adjust the level of water in the tank. The tank 23 serves as an expansion tank that absorbs the expanded water when the hot water expands from the hot water tank 71. The water supply tank 23 supplies water when the water level in the hot water tank 71 falls, and accordingly, when the water level in the water supply tank 23 falls below a set level, the float 72 operates to supply water. The valve 73 is automatically opened to act to replenish insufficient water.

On the other hand, the hot water tank 71 is provided on the lower side of the hot water tank 71 after the heat exchange takes place through the heat exchanger pipe buried in the ground of, for example, the hot water circulation outlet 48 is installed thereon The hot water circulation inlet 49 is returned.

In the lower part of the combustion chamber 24A, a copper coil 31 having a conical shape and a copper (Cu) line is installed, and an upper end of the copper coil 31 communicates with a waste oil tank 41. One end of the supplied oil supply pipe 32 is connected. The copper coil serves to promote the ignition by contacting the hot metal body while guiding the flow of the waste oil, and the material and shape can be adopted as long as the material has high thermal conductivity, high temperature resistance, and durability. Any coil shape such as the above can be used.

The waste oil tank 41 is provided with a waste oil inlet 52 on an upper portion of one side, as shown in Figure 3, the inside of the waste oil 76 using water 75 or foreign matter, etc. using a specific gravity difference Two first and second purification plates 41A and 41B which are sequentially lowered toward the outlet 77 side of the tank in order to filter them out, and on the outlet side the fluidity of the waste oil 76 in winter The hot water pipe 74 for improving is disposed in the form of a coil and connected to the hot water tank 71. In Fig. 3, reference numeral 50 designates an air hole and 51 designates a level gauge.

In addition, the outlet 77 of the waste oil tank 41 is connected to a fuel filtration device 42 for filtering the water 75 contained in the waste oil 76 secondaryly, the structure of which is shown in FIG. Likewise, the waste oil inlet 42A and the waste oil outlet 42B are disposed above the fuel filtration device 42 to filter the water 75 having a specific gravity greater than the waste oil to the lower portion. Further, a drain device 42C for discharging the filtered water 75 is provided below the fuel filtration device 42.

Furthermore, the oil supply pipe 32 connected to the outlet 42B of the fuel filtration device 42 has a manual oil valve 30 for manually adjusting the supply amount of the waste oil supplied to the combustion chamber 31 and a solenoid which is controlled to be opened and closed electronically. The valve 29 is provided.

On the other hand, the flame inlet pipe 78 through which the flame for preheating the combustion chamber 24A from the petroleum burner 21 is connected to the lower side of the combustion chamber 24A at a height corresponding to the copper coil 31. In addition, when connected to the combustion gas discharge pipe 79 through the drag removal device 37 to be described later to supply fresh air at the initial stage of the ignition of the oil burner 21 and the waste oil is ignited and burned in the combustion chamber 24A An oxygen supply pipe 40 is connected to recycle a part of the combustion gas discharged to the outside to achieve complete combustion.

The flame inlet pipe 78 is provided with a switch 22 which is opened and closed in accordance with the operation of the oil burner 21, the switch 22 is opened and closed in conjunction with the operation of the solenoid (23). In addition, an oil burner fan 21A is installed inside the oil burner 21 to supply flame and hot air into the combustion chamber 24A during burner operation.

On the other hand, the upper portion of the combustion chamber 24A has one end protruding from the inside of the combustion cylinder 24 so that the heated hot air combusted in the combustion chamber 24 immediately escapes from the combustion chamber 24A via the communication 28. A fire plate 27 is formed to shut off and stay inside the combustion chamber for a long time.

In the middle of the combustion chamber 24A, an air injection pipe 26 for discharging fresh air supplied from the blower 25 provided outside the boiler to the room while forming a vortex (vortex) is disposed in the vertical direction. In order to form a vortex of the air injection pipe 26, an air injection hole 26A is formed in the vertical direction in a symmetrical manner as shown in FIGS. 5A and 5B. In this case, if the air injection port is a structure that forms a vortex, it is also possible to form a different injection port.

Here, the lower end of the air injection port 26A needs to be positioned at an appropriate distance from the ignition portion, for example, 32 ± 5 mm. If the distance is out of the above range, incomplete combustion occurs, smoke is generated, and thermal efficiency is reduced.

On the other hand, the vertical communication 28 is connected to the upper part of the combustion cylinder 24, and this communication is made so that the edge part may face downward through a horizontal bending part. A plurality of water spray nozzles 34A and 34B, for example, are provided with a height difference in the downward communication 28, and the water spray nozzles 34A and 34B are installed from the water tank 38. Ascending to the high pressure by the circulation pump 39 is injected into the communication. A collecting cylinder 80 for collecting the injected water to collect the soot such as dust in the exhaust gas discharged through the communication is disposed in the lower portion of the communication 28, the collecting cylinder 80 is a soot in the middle It is connected to the water tank 38 through the filter 35 for filtering out impurities such as.

In addition, the upper portion of the collecting container 80 is connected to the oxygen supply pipe 40, and also connected to the discharge pipe 79 through the air cleaner 36.

On the other hand, the inside of the hot water tank 71 is provided with a temperature controller 58 for stopping the operation of the boiler when the temperature of the hot water reaches the set temperature, for example, it may be configured using a bimetal.

In FIG. 2, reference numeral 44 denotes a thermometer, 45 a pressure gauge, 46 a pressure stabilizer, 47 a control box, and 81 a petroleum tank.

Hereinafter, the operation of the smokeless hot water boiler using the waste oil according to the present invention configured as described above will be described in detail with reference to FIG. 6.

First, when the main power switch 53 of the boiler is turned on, the power supply relay R 59 is turned on to close the contact R-a. As a result, the fan 25 operates to blow the vortex air into the combustion chamber 24 through the air injection pipe 26, and at the same time, the oil burner 21 is ignited to burn the burner. Burner pan (BF) 21A is activated.

At the same time, the solenoid (S1) 23 for the switch is turned on so that the switch 22 of the flame inlet pipe 78 is opened, and the flame of the burner 21 enters into the combustion chamber 24. In this case, the burner timer T3 60 and the fuel switch timer T4 61 are also started to start counting 5 minutes and 3 minutes, respectively. That is, the combustion chamber 24 is preheated by the petroleum burner 21 for 3 minutes.

Three minutes thereafter, the solenoid valve S2 29 for fuel switchgear is operated by the timer T4 61, i.e., the contact T4-a is closed to remove the fuel filter device from the waste oil tank 41. Waste oil having passed through 42 is introduced into the combustion chamber 24 through the oil supply pipe 32. The injected waste oil comes down along the copper coil 31 and is heated by the flame supplied from the oil burner 21 and heated by the copper coil 31 heated to a high temperature during the preheating period.

After 2 minutes of operation of the solenoid 29 for the fuel switch, the oil burner timer T3 60 is activated to open the timer contact T3-b to the burner 21 so that the oil burner is turned off. Off. At the same time, when the contact T3-a is closed and the timer T2 57 starts counting and 10 seconds have elapsed, the contact T2-b is opened and the oil burner fan 21A is operated for 10 seconds further. As the oil burner 21 is extinguished, incomplete combustion gas of petroleum generated momentarily is pushed into the combustion chamber 24 so that complete combustion is achieved.

In addition, since the solenoid 23 for the switch is turned off according to the opening of the contact point T2-b, the switch 22 is closed and the combustion chamber 24 and the flame inlet pipe 78 are blocked, so that the oil burner 21 is replaced with the combustion chamber 24. ) Can be protected from heat.

Then, according to the combustion of the waste oil, the main burner is operated to increase the temperature of the water stored in the hot water tank 71. As a result, when the temperature rises to the set temperature, the temperature controller 58 is operated to supply power to the power supply relay 59. The power supply to the power supply is cut off, and the blower timer (T1) 56 is started for 10 minutes.

As a result, the fuel opening and closing solenoid 29 is turned off to stop the supply of the waste oil from the waste oil tank 41 to the combustion chamber 24. In this case, the blower 25 is continuously operated for 10 minutes, and then the contacts T1-b are opened to stop the operation. As a result, the remaining amount of waste oil injected into the combustion chamber 24 is combusted.

After that, when the temperature of the hot water tank 71 is lowered below the set temperature, the temperature controller 58 is set to the reset state again so that power is supplied to the power supply relay 39. Therefore, the operation of the boiler is started again from the start of the burner 21 described above.

In FIG. 6, reference numeral 54 denotes an ammeter, and 55 denotes a voltmeter.

The reason for preheating the combustion chamber 24 with the petroleum burner 21 in the operation of the boiler as described above is to increase the temperature inside the combustion chamber 24 to facilitate the ignition of the waste oil. Can be suppressed. In this case, a structure for preheating the inside of the combustion chamber in advance may be adopted as long as the burner device capable of automatically igniting with low generation of smoke in addition to using a petroleum burner.

In addition, the air injection pipe 26 is connected to the blower 25 located in the center of the boiler needs to be positioned at a proper distance from the ignition portion, and injected compressed air through the air injection port 26A of the symmetrical structure Therefore, oxygen is supplied to the combustion of the waste oil while forming a vortex in the combustion chamber 24 to help complete combustion.

Furthermore, the copper coil 31 has a structure suspended in a spiral shape at the end of the oil supply pipe 32 located at the lower end of the combustion chamber 24, and the waste oil injected into the oil supply pipe 32 descends on the copper coil 31. Combustion proceeds to complete combustion without generating slag. As a result, the odor is removed and high temperature heat is generated. In this case, the copper coil 31 may be formed in any other shape capable of guiding the waste oil in addition to the above-described spiral.

In addition, the bottom plate 82 of the combustion chamber 24 is preferably formed of a high-strength carbon steel material, which is less affected by heat and does not entangle impurities.

Meanwhile, in the present invention, the lower end of the combustion chamber 24 is sequentially connected to the draw removal device 37 and the combustion gas discharge pipe 79 through the oxygen supply pipe 40 to supply oxygen at the ignition of the oil burner 21. After combustion, a part of the exhaust gas is recycled to completely burn the incomplete combustion gas, thereby preventing heat loss while suppressing the emission of CO gas.

In addition, the water spray nozzles 34A and 34B connected to the communication 28 may collect dust contained in the smoke discharged to the outside and collect the dust into the collection container 80, thereby suppressing the discharge of the smoke. Furthermore, the discharge pipe 79 is provided with an air cleaner 36 to perform a double dust removal function.

Meanwhile, in the present invention, only the waste oil is supplied to the combustion chamber 24 in a state in which water and foreign substances are separated from the waste oil according to water and waste oil separation using the difference in specific gravity in the waste oil tank 38 and the fuel filtration device 42. It was raised so that incomplete combustion did not occur.

In addition, in the present invention, the operation of the boiler is controlled by the control box 47, so that it is possible to control it completely automatically, so that it is easy to manage, and the boiler can be operated at an optimum state. It can prevent the growth of the crops or horticultural crops in the inside or the verbs and prevent the consumption of manpower required for boiler management. In addition, the fuel cost can be reduced by more than 70% compared to the existing one, and thermal efficiency is superior to existing diesel boilers, and slag and smoke are not generated, which does not cause environmental pollution, and thus functions as a waste oil incinerator.

As described above, in the present invention, the preheating structure using the petroleum burner suppresses the generation of trailing oil during the initial ignition of the waste oil, induces complete combustion by the vortex forming air injection pipe and the high-conductivity copper coil, and recycles the exhaust gas. By the structure, part of the incomplete combustion gas is returned to the combustion chamber and at the same time, it is possible to block the discharge of the draw by the smoke spray system using the water spray device and the air cleaner, and the fuel cost is also significantly reduced compared with the conventional method.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the present invention is not limited to the spirit of the present invention. Various changes and modifications can be made by those who have

Claims (9)

A boiler body which forms a combustion chamber inside the center and has a hot water tank connected to the boiler pipe at the upper and lower sides of the combustion chamber outside; Air supply means for blowing external air at high pressure into the combustion chamber; A waste oil tank storing waste oil to be combusted, First refining means for refining water and foreign substances contained in the waste oil by using a specific gravity difference; Waste oil guide means for supplying the refined waste oil from the waste oil tank through the refining means into the combustion chamber; It is formed of a high thermal conductivity material at the lower end of the combustion chamber and is connected to the waste oil guide means for ignition promoting means for stimulating the ignition by guiding the waste oil supplied therein to flow along; Preheating means connected to the lower end of the combustion chamber for preheating the inside of the combustion chamber for a predetermined time only during the initial ignition; Dust removal means for removing the dust contained in the exhaust gas is installed in a communication connected to the upper end of the combustion chamber in a dual manner; At the time of initial ignition, after operating the preheating means for a predetermined time, the waste oil is introduced into the combustion chamber through the waste oil guiding means, and combustion control for blocking the introduction of the waste oil when the temperature of the hot water tank rises above the set temperature. Smokeless hot water boiler using waste oil, characterized in that consisting of means. 2. The lead-free hot water boiler using waste oil according to claim 1, wherein the control means further operates the air supply means for a predetermined time so that slag does not remain in the combustion chamber when the waste oil is blocked. The method of claim 1, wherein the preheating means comprises a petroleum burner, a flame induction pipe for guiding the flame of the petroleum burner into the combustion chamber, and a time set at the operation of the petroleum burner and opened at the operation of the oil burner. A lead-free hot water boiler using waste oil, characterized in that it consists of a switch that is closed after. According to claim 1, wherein the dust removing means is installed in a vertical portion extending downward from the communication and the first dust removing means for collecting the dust discharged in the water spray method, and at the rear end of the dust removing means Lead-free hot water boiler using waste oil, characterized in that consisting of an air cleaner connected to remove the residual dust. The method of claim 1, further comprising an oxygen supply pipe connected between the dust removal means and the lower end of the combustion chamber to supply oxygen during initial ignition and to recycle a part of the exhaust gas during combustion to induce complete combustion. Lead-free hot water boiler using waste oil. 2. The lead-free hot water boiler using waste oil according to claim 1, wherein the air supply means injects external air while forming a vortex from a vertical end located inside the combustion chamber. The unleaded hot water boiler using waste oil according to claim 1 or 6, wherein the distance between the lower end of the air supply means and the combustion section is set within a range of 32 ± 5 mm. The lead-free hot water boiler using waste oil according to claim 1, wherein the ignition promoting means comprises a spiral copper copper wire. The waste oil tank of claim 1, further comprising second purifying means for purifying water and foreign matter contained in the waste oil by using a specific gravity difference, and heating means for increasing fluidity of the waste oil. Smokeless hot water boiler with waste oil.