KR100515577B1 - Apparatus and process for treatment of waste oils - Google Patents

Abstract

The present invention relates to a treatment apparatus and a method for regenerating fuel oil from waste oil. The apparatus and method of the present invention are characterized by pyrolysing waste oil by combining sequential pressurization and vacuum conditions at high temperatures. While the conventional batch method proceeds with 400-450 ° C., the method of the present invention undergoes rapid pyrolysis at 300-350 ° C., which is lower than this. The method of the present invention is a semi-continuous method with an evacuation process to remove ash from the pyrolysis vessel and therefore does not require an outage step to collect ash. In addition, the content of ash mass is also lowered from 5% to 1.4% of the prior art because the slow reaction rate that causes the oxidation problem associated with the formation of the tar compound is lost. In addition, the production rate of second-class diesel fuel oil can be increased by three times as compared to the conventional batch process.

Description

Apparatus and process for treatment of waste oils

The present invention relates to a treatment apparatus and a method for regenerating fuel oil from waste oil.

Waste engine oils and lubricating oils from industrial sites are not only harmful to the environment but also cause problems in their treatment. They are collected by public service agencies and sent to commercial facilities where they are recycled through centrifugation and filtration and sold in the form of regenerated lubricating oils. The regenerated oil is also sold as a fuel source such as a boiler. This waste oil is often subjected to a pyrolysis process to make a second grade diesel oil.

Lubricant oils are prepared when crude oil is typically placed in a boiling temperature range of 300-500 ° C. However, when lubricating oils, including synthetic oils, function within the bulkhead of the engine, they usually capture dust and heavy metal components from the metal parts of the engine and the fuel used. Thus, conventional used oils will contain significant amounts of cadmium, chromium, zinc and lead. On the other hand, prolonged use of the oil in the engine makes the lubricating oil easy to undergo depolymerization, which in turn results in the production of short hydrocarbons of low boiling point. In addition, the process of removing the lubricating oil from the engine inevitably involves the process of cleaning with a solvent, a cleaning agent and water.

Thus, there is a need for the development of efficient pyrolysis processes to replace used oils with useful products such as diesel oils and to reduce environmentally harmful solids and sludge.

U. S. Patent Nos. 5,286, 349 and 5, 271, 808 disclose devices for regenerating useful oil products from waste oil. According to the description of the device, the device basically comprises a kettle-type boiler of the prior art, in which the boiled material is regenerated using a condenser. 1 is a schematic diagram of a pyrolysis apparatus for illustrating a pyrolysis process according to the prior art, which is the same as FIG. 3 of US Pat. No. 5,871,618. Referring to FIG. 1, the pyrolysis apparatus includes a pyrolysis vessel 101 consisting of a lid 106, sidewalls 105, a bottom 102 and an upper outlet 120. Prior art devices for regenerating oil products from waste oil are described in US Pat. No. 5,871,618, where an open batch type pyrolysis vessel used at atmospheric pressure is employed. This prior art device is somewhat more advanced than the techniques disclosed in US Pat. Nos. 5,286,349 and 5,271,808, but still has the problem that it takes a long time to raise and react.

In addition, the apparatus of the prior art, as shown in FIG. 2, requires an interruption step for removing an ash cake which takes at least 10 hours every 3.5 days. 2 is a graph showing time versus temperature curves in the manufacturing process cycle of the prior art device. In the technique disclosed in US Pat. No. 5,286,349, it should be noted that applying heat only to the bottom of the container causes the sludge mass to be produced. In addition, this results in different temperature ranges from the bottom to the top of the waste oil in the vessel, which not only degrades the efficiency of the pyrolysis process but also creates more sludge mass at the bottom of the vessel.

Therefore, according to the prior art apparatus and method, excessive energy demand, large reaction time, large reactor and low production rate are unavoidable. In particular, the large volume of raw material takes a long time to react, which leads to undesirable polymerization, oxidation and dehydrogenation reactions, which lead to the generation of unstable diesel fuel and large volumes of sludge mass as described in US Pat. No. 6,132,596. do. Disadvantages of these prior arts include unnecessary by-products such as physical damage to the structure of the pyrolysis vessel due to the use of high temperatures of 450-500 ° C., structural modifications, high production costs, and too short hydrocarbon fragments. Generation is included.

Therefore, the technical problem of the present invention, in order to overcome the disadvantages caused by the conventional batch type waste oil pyrolysis process, a semi-continuous waste oil treatment apparatus by a combination of pressurized and vacuum modes and the like and To provide a way.

Another technical problem of the present invention is a waste oil treatment apparatus capable of achieving the same or better production rate as the prior art even when using a relatively small container compared to the prior art by the high reaction rate under sequential pressurization and vacuum conditions And a method.

Another technical problem of the present invention is to provide a waste oil treatment apparatus and method which exhibits a production rate equivalent to or better than that of the prior art, even if a relatively low process temperature is employed.

Another technical problem of the present invention is to provide a waste oil treatment apparatus and method capable of removing the sludge mass to be solidified by using a bleeding valve at the bottom of the container without interrupting the process for wiping and removing solid contaminants. It is.

Waste oil treatment apparatus of the present invention for solving the above technical problems:

A pyrolysis vessel capable of maintaining airtightness;

A waste oil tank for storing waste oil to be supplied to the pyrolysis vessel;

Pressing means for raising an internal pressure of the pyrolysis vessel;

A vacuum pump capable of vacuuming the interior of the pyrolysis vessel;

A high pressure reducing valve for reducing excessive pressure in the pyrolysis vessel;

A heater that surrounds the pyrolysis vessel as a whole and uniformly heats waste oil contained in the pyrolysis vessel;

A discharge valve for discharging the ash mass which is solidified at the bottom of the pyrolysis vessel to the outside;

Characterized in having a.

Waste oil treatment method of the present invention for solving the above technical problems:

(a) increasing the pressure in the pyrolysis vessel to 50-100 psi while introducing waste oil into the pyrolysis vessel by a high pressure pump;

(b) heating the temperature in the pyrolysis vessel to reach approximately 200 ° C .;

(c) opening the pyrolysis vessel slightly to release the trapped air into the atmosphere and then closing it again;

(d) heating the temperature in the pyrolysis vessel to maintain a constant temperature within 300-350 ° C., to proceed with the pyrolysis process until approximately 50% of the waste oil is removed;

(e) stopping heating to the pyrolysis vessel and depressurizing the pressure within the pyrolysis vessel to be approximately 10 ⁻⁶ torr;

(f) if up to approximately 70% of the waste oil is removed, removing the vacuum pressure in the pyrolysis vessel;

Characterized in having a.

In the present invention, it is preferable to pressurize the pyrolysis vessel to 300 psi to accelerate the reaction time about three times faster than the reaction time of the conventional batch process. The high pressure relief valve or pneumatic valve connected to the PLC is set to 300 psi and connected to the inlet of the distillation column. For emergencies such as excessive pressure, a high pressure burst valve set at 350 psi is mounted on top of the pyrolysis vessel in connection with the safety tank. Therefore, when the waste oil begins to pyrolyze and the pressure reaches 300 psi, the high pressure relief valve is opened by pneumatic pressure to send the pyrolyzed oil gas to the distillation column. This results in a process about three times faster than the prior art.

In addition, in the present invention, it is preferable to vacuum the pyrolysis vessel to accelerate the reaction faster than the reaction of the conventional batch process, because the vacuuming lowers the boiling point of the pyrolyzed oil and pyrolyzes the pyrolyzed low molecular weight compounds. This is because it saves energy and time much faster by removing it from the container.

It is also preferred in the present invention that heat is applied to the side walls as well as to the bottom of the pyrolysis vessel so that no different temperature zones are present in the vessel.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention.

3 is a view for explaining the waste oil treatment apparatus and treatment method according to an embodiment of the present invention employing sequential pressurization and vacuum conditions.

Waste oils, such as engine oils, metal cutting oils, hydraulic oils and the like, basically contain water, solvents and detergents when they are transported to a pyrolysis plant. The water is removed before the waste oil enters the pyrolysis vessel 30. Valves 31 and 32 are closed and valve 39 is opened before oil is pumped in. The waste oil from which the water in the waste oil tank 29 is removed is put into the pyrolysis vessel 30 using the high pressure pump 38. This high pressure pump 38 increases the pressure in the pyrolysis vessel 30 to 50-100 psi while allowing waste oil in the waste oil tank 29 to enter the pyrolysis vessel 30. By the way, the pyrolysis vessel 30 may be previously pressurized to 200 psi by the argon gas 44 depending on the situation. Heat is not only applied directly to the bottom of the pre-pressurized pyrolysis vessel 30 but also directly to its side walls. Before heat is applied to the pyrolysis vessel 30, it is preferable to pressurize the pressure in the pyrolysis vessel 30 with argon gas 44 at a pressure of 100 to 150 psi in advance to accelerate the reaction.

When the temperature in the pyrolysis vessel 30 reaches approximately 200 ° C, the high-pressure reducing valve 31 is slightly opened to release air trapped in the pyrolysis vessel 30 to the atmosphere and then closed. The valve connected to the argon tank may be open to compensate for pressure loss. After approximately 1.0 to 1.5 hours, the temperature continues to rise and reaches 300 to 350 ° C. The waste oil begins to decompose, producing high boiling point and low molecular weight hydrocarbons, which increases the pressure and is completely controlled by the programmable logic controller (PLC). Open the controlled high pressure relief valve 31. Optimization of prepressurization is an important factor in determining the ratio of pressure and temperature that varies depending on the size of the vessel and the capacity of the waste oil. In general, it is preferable to fill the container with 70-80% of waste oil. Welding argon is used only at the beginning of each semi-continuous cycle to increase the pyrolysis reaction rate as the pressure in the vessel increases. This pressure increases as the pyrolysis process proceeds, because pyrolysis results in the formation of high boiling, low molecular weight hydrocarbons.

In urgent cases, such as excessive internal pressure being generated in the pyrolysis vessel 30, a rupture valve 41 mounted on top of the pyrolysis vessel 30 may be ruptured by excessive pressure, in which case hot waste The internal pressure with some of the oil leaks into the safety tank 42 which is physically separated from the pyrolysis vessel 30. This can prevent fire or explosion. Thus, the pressure gauge 40 can be monitored during the whole process or connected to a PLC so that automatic shut down can be performed.

Pyrolysed oil in gaseous form, low boiling point and low molecular weight hydrocarbons is discharged to the distillation tower and condenser for further cleaning. This pyrolysis process at high temperature and high pressure takes about 1.5 hours and continues until approximately 50% of the waste oil is removed. A level gauge 43 or floating level indicator may be used to read the level of waste oil remaining in the pyrolysis vessel 30.

During the pressurization mode of the pyrolysis process, the release valve 34 controlled by the PLC continues to open to slowly flow the ash mass which solidifies at the bottom of the pyrolysis vessel 30 into the storage tank 37. The waste oil at the top of the storage tank 37 is recycled to the waste oil tank 29 after passing through the valve 36 and the pump 35, and the waste oil at the bottom of the storage tank 37 is heated or spray dried. To form a solid ash mass.

When about 50% of the waste oil is pyrolyzed and distilled in the pyrolysis vessel 30, the pressurized mode is switched to the vacuum mode. The high pressure relief valve 31 opens slowly and completely for pressure reduction in the pyrolysis vessel 30. In addition, the heater surrounding the pyrolysis vessel 30 must be turned off because the temperature in the vacuum mode in the 300-350 ° C. range is still sufficiently high. In this vacuum mode, 50% of the remaining pyrolysis oil is made to boil, which is often preferred for safety purposes. When the pyrolysis vessel 30 is depressurized by completely opening the high pressure reducing valve 31, the valve 32 is opened while closing the high pressure reducing valve 31 and starting the operation of the vacuum pump 33. At this time, it is preferable to vacuum to at least 10 ^-6 torr.

As the vacuum pump 33 continues to vacuum the pyrolysis vessel 30, the residual oil begins to boil, which not only accelerates the removal of the pyrolyzed oil in the pyrolysis vessel 30 but also increases the reaction rate. This step takes approximately 0.5 hours and completes the incomplete pyrolysis process in pressurized mode. A vacuum degree of at least about 10 ⁻⁶ torr is preferred depending on the temperature in the pyrolysis vessel 30.

After approximately 20% of the oil remaining in the pyrolysis vessel 30 is typically removed by the vacuum mode, the vacuum pump 33 is stopped and the valve 39 is opened to remove the vacuum pressure in the pyrolysis vessel 30. Thus, approximately 70% of waste oil is distilled from the pyrolysis vessel 30 through a pyrolysis process by sequential pressurization and vacuum modes, and the whole process is repeated again by replenishing the pyrolysis vessel 30 with fresh waste oil.

4 is a graph showing the relationship between temperature, pressure and reaction time during a process according to an embodiment of the invention. Referring to Figure 4, it can be seen that the total reaction time was 4.0 hours. The size of the vessel and the capacity of the waste oil are 2,500 L and 1,800 L, respectively, which means that 72% of the vessel is filled. The volume produced is from 1,800 L to 1,900 L, which is equal to or slightly higher than the input volume, because the volume increase occurs during depolymerization despite the formation of sludge masses and tars. This yield is 2.9 times better than the batch type device disclosed in US Pat. No. 5,871,618.

What may optionally be further included in the operation of this embodiment is that the vacuum mode may be preceded to remove the gas containing oxygen in the waste oil prior to the pressurized mode. This may help to avoid the problem of early oxidation that may occur during the pyrolysis process, which is known to be a major factor in tar generation.

The PLC controls all the valves, heaters, gauges and pumps shown in FIG. In addition, probes are connected to the PLC for proper monitoring.

Table 1 below shows a typical analysis of the feedstock waste oil and the oil produced.

Foil Oil produced water(%) 6.00 0.05 Ash (%) 2.47 <0.01 sulfur(%) 0.213 0.069 carbon(%) 83.02 82.65 Hydrogen(%) 14.26 13.23 Nitrogen (ppm) 489 98.5 Specific gravity, 24/25 ℃ 0.905 0.807 Specific gravity, 15/15 ℃ 0.909 0.819 Flash point (℃) 42 38 Density-API 24.23 40.39 Calorific Value (BTU / lb) 18963 19631 Color-ASTM Not available 2.5

The characteristics and effects of the present invention are summarized as follows.

1) Since the waste oil treatment apparatus of the present invention includes a container operating at a single pressure and in a vacuum, its configuration is simple.

2) The combination of pressurization and vacuum modes can accelerate the reaction rate by at least three times compared with the prior art.

3) It is possible to use a container which is about 1/6 smaller than the conventional container which is processed at atmospheric pressure.

4) The use of relatively small vessels reduces the energy required to heat the pyrolysis vessel interior.

5) By using a container of relatively small size, heating time and reaction time can be reduced.

6) The bleeding process can prevent process interruptions that were necessary in conventional batch vessels to remove solidified ash mass at the bottom of the pyrolysis vessel.

7) There is no need to use an impeller agitator because agitation is not necessary to prevent solidification of the ash mass at the bottom of the pyrolysis vessel.

8) It can be used at low temperature of 300 ~ 350 ℃ by using high pressure.

9) Evenly applied heat around the pyrolysis vessel does not produce different temperature ranges and reduces the occurrence of sludge masses.

10) By using vacuum process, distillation rate and production rate are increased, and pyrolysis time is reduced.

1 is a schematic diagram of a pyrolysis apparatus for illustrating a pyrolysis process according to the prior art;

2 is a graph showing a time versus temperature curve in a manufacturing process cycle of a device of the prior art;

3 is a view for explaining a waste oil treatment apparatus and a treatment method according to an embodiment of the present invention employing sequential pressurization and vacuum conditions; And

4 is a graph showing the relationship between temperature, pressure and reaction time during a process according to an embodiment of the invention.

Claims (10)

In the waste oil treatment apparatus for regenerating fuel oil from waste oil, A pyrolysis vessel capable of maintaining airtightness; A waste oil tank for storing waste oil to be supplied to the pyrolysis vessel; Pressing means for raising an internal pressure of the pyrolysis vessel; A vacuum pump capable of vacuuming the interior of the pyrolysis vessel; A high pressure reducing valve for reducing excessive pressure in the pyrolysis vessel; A heater that surrounds the pyrolysis vessel as a whole and uniformly heats waste oil contained in the pyrolysis vessel; A discharge valve for discharging the ash mass which is solidified at the bottom of the pyrolysis vessel to the outside; Waste oil processing apparatus having a. The method of claim 1, A burst valve for releasing excessive pressure by rupturing in an emergency such as excessive internal pressure being generated in the pyrolysis vessel; A safety tank connected to the rupture valve to store waste oil discharged; Waste oil processing apparatus further comprising a. The method of claim 1, A storage tank for storing waste oil including lumps from the discharge valve; Means for recycling waste oil in the storage tank connected to the storage tank to the waste oil tank; Waste oil processing apparatus further comprising a. The method of claim 1, The pressing means is: A pump for supplying waste oil from the waste oil tank to the pyrolysis vessel; An argon tank connected to said pyrolysis vessel; Waste oil treatment apparatus, characterized in that each consisting of. The method of claim 1, A level gauge for measuring the level of the waste oil; A temperature probe measuring the temperature of the waste oil; Waste oil processing apparatus further comprising a. The method of claim 5, And a PLC for controlling the valve, the probe, the heater, the gauge, and the pump. (a) increasing the pressure in the pyrolysis vessel to 50-100 psi while introducing waste oil into the pyrolysis vessel by a high pressure pump; (b) heating the temperature in the pyrolysis vessel to reach approximately 200 ° C .; (c) opening the pyrolysis vessel slightly to release the trapped air into the atmosphere and then closing it again; (d) heating the temperature in the pyrolysis vessel to maintain a constant temperature within 300-350 ° C., to proceed with the pyrolysis process until approximately 50% of the waste oil is removed; (e) stopping heating to the pyrolysis vessel and depressurizing the pressure within the pyrolysis vessel to be approximately 10 ⁻⁶ torr; (f) if up to approximately 70% of the waste oil is removed, removing the vacuum pressure in the pyrolysis vessel; Waste oil treatment method comprising a. The method of claim 7, wherein And a step of pre-pressurizing the pressure in the pyrolysis vessel with argon gas to a pressure of 100 to 150 psi before the step (b). 8. The method of claim 7, wherein in the step (a), the waste oil is filled in the pyrolysis vessel with 70 to 80%. The waste oil treatment method according to claim 7, wherein in the steps (a) to (d), the bottom of the pyrolysis vessel is opened to release the lumps which solidify.