PT108075B - HYDROCARBON PRODUCTION MECHANISM BY PLASTIC WASTE PYROLYSIS AND METHOD OF PRODUCTION - Google Patents

Abstract

THIS INVENTION FITS IN THE ENVIRONMENT AND ENERGY AREAS AND HAS AS A FINAL RESULT THE PRODUCTION OF A LIQUID FUEL FROM PLASTIC MATERIAL RECYCLING, BASED ON A NEW FAST PYROLYSIS PROCESS. THE INVENTION IS A EXTERNAL REACTOR (1), AN INTERNAL REACTOR (12), TWO GAS BURNERS (9) LOCATED IN THE EXTERNAL REACTOR'S WALLS (1), WHERE THE MAIN BURNER IS LOCATED (7) ), A CIRCULAR DISTRIBUTION BOX (5), A HEAT EXCHANGER (13), A GAS COMPRESSOR AND A WATER COOLING SYSTEM. A NEW FEATURE IS THE USE OF TWO CONCENTRIC AND CIRCULAR REACTORS, IN WHICH THE EXTERNAL REACTOR (1) PROVIDES HEAT TO THE PYROLYSIS PROCESS. In addition to the mechanism, it is also intended to patent the method of operation.

Description

DESCRIPTION

SYSTEM OF PRODUCTION OF HYDROCARBONS BY PYROLYSIS OF

PLASTIC WASTE AND PRODUCTION METHOD OF THE SAME

Brief introduction to the invention concept of sustainability has prevailed in the 21st century, with the international community becoming increasingly aware of the need to reduce environmental problems and, therefore, committed to the achievement of ambitious objectives in the environmental area.

One of the main objectives is the gradual and significant reduction in emissions of polluting gases.

These environmental issues are particularly relevant in the energy sector, where there is an increasing demand for alternative energies, clean and at a lower cost, which also allow to reduce the existing dependence on oil and its direct derivatives (diesel and gasoline ).

Thus, the recycling of waste for the production of fuels assumes an extremely important role, as it simultaneously contributes to the objectives in terms of the environment and energy production.

The present invention fits in the areas of the environment and energy and has as its final result the production of a liquid fuel (diesel) from the thermochemical recycling of plastic materials, based on a new process of rapid pyrolysis.

It foresees a reuse of plastic, in hydrocarbons, which new and improved way of through its transformation can be used as substitutes for oil.

One of the main advantages of this method for the production of hydrocarbons is that it proposes an alternative use to direct burning for plastic waste, which is not limited to recycling them, thus contributing to the reduction of environmental problems.

In addition, the waste pyrolysis process contributes to the rational use of oil as a source of energy. Through this process, the heavier hydrocarbons are transformed into hydrocarbons of lower molecular weight (liquid or gaseous), through thermochemical degradation, in the absence of oxygen, and condensation by cooling.

In this way, it can be said that this invention provides a new way of recycling plastic waste, with a view to obtaining hydrocarbons, which can be used, namely, in the oil and petrochemical industries.

In addition, this plastic transformation process is self-sufficient from the point of view of thermal energy, since part of the gases generated are burned to provide the necessary heat for pyrolysis reactions.

State of the art of the invention

In research of the state of the art of the invention, which was carried out with the objective of assessing whether it had already been thought or executed by third parties, the following patent documents were identified, of which we highlight its distinction with the present invention.

- Yoshioka, T. at al, Pyrolysis of poly (ethylene terephthalate) in a fluidized bed plant, 2004, Elsevier - describes pyrolysis in a fluidized bed system consisting of a fluidized bed reactor, a cyclone, an electrostatic precipitator, a compressor , a preheater and a cooler. Now, as will be seen below, this system does not comprise all the components of the present invention, the embodiment of the invention being different.

- US20140027265A1 - this invention describes a method for producing hydrocarbons from carbon-containing materials, using a fluidized bed pyrolysis reactor and a solid catalyst. However, this patent describes only one method, no product is claimed, unlike the present invention which is product and method.

In addition to the analysis of the aforementioned patent application, the two reactors used separately, not one internal and one external, as will be described in the present invention.

- CN202359074U - the present invention describes a mechanism in which to produce hydrocarbons through plastic pyrolysis, two fluidized beds are used, one with low temperature and the other with high temperature. Now, in the case of the mechanism now claiming the fluidized bed there is only one, which is being cooled throughout the process.

- Garforth, A. A et al, Production of hydrocarbons by catalytic degradation of high density polyethylene in a laboratory fluidized-bed reactor, 1998, Elsevier - in this article only one reactor is described and not two as the invention now claimed.

- EP0008169A1 - also in the case of this invention only a reactor is used, in addition the method of production is different from the method now claimed in the present invention.

- In patent application no. WO03029384 the plastics are fed in batch mode and on a hot surface, that is, the entire quantity of plastics to be processed is fed to the reactor at the same time, and all this mass of plastics will have to be be heated at the same time, until the reaction temperatures are reached, which causes the final product (which leaves the reactor continuously) to vary and fluctuate in terms of composition and flow (which starts from being low, increases until reaching a maximum and then decreases to zero, when plastics are fed back).

In patent application no. WO03029384 feeding a large quantity of cold plastics on a hot surface poses risks of material aggregation and consequent clogging.

In the present invention, the plastics are fed to the reactor by pneumatic transport, which consists of a transport tube surrounded by an annular exchanger, in which cold water circulates on the outside and a process gas flow passes through the interior, which drags plastics into the reactor.

- 5 The advantage of the present invention over patent application No. WO03029384 is that this method allows a continuous and stable supply of plastics to the reactor, and the fact that the transport tube is cooled, prevents the plastics from heating up, they fuse and clog the supply system before entering the reactor.

In the present invention the feeding of plastics, as well as the operation of the reactor is carried out continuously and under constant and stabilized operating conditions. The use of the fluidized bed in sand, which has heat transfer coefficients much higher than those of steel and gas (which are the heat transfer mechanisms described in patent application no. WO03029384), allows the processing of a higher amount of plastics per unit of reactor volume, in relation to patent application no. WO03029384. In the present invention, due to the residence time of the material, being a few seconds, it is possible to obtain a final product with constant and consistent physicochemical characteristics over time, and also at a constant flow rate. The level of industrial use allows for easy integration with the unit operations that are intended to be installed downstream, for processing the final product, which is no longer the case with patent application no. WO03029384.

The constant movement of the fluidized bed of sand described in the present invention, also promotes the mixing and separation of the plastics, thus preventing their aggregation and the consequent occurrence of clogging.

The present invention can easily be integrated into an industrial installation, unlike the technology described in patent application no. WO03029384.

Since the main purpose of pyrolysis is to produce a product that is mostly liquid at room temperature, it implies that some of the gases that leave the reactor will have to be condensed. In the case of patent application No. WO03029384, the equipment located downstream will have to be dimensioned in order to be able to process the peak production of the reactor. But only for part of the time will this maximum capacity be operated, the rest will be underutilized, since they will have to deal with fluctuations in production, both in terms of thermal needs and in the flow of gas to be processed. . The one that implies higher investment costs, which will not be fully profitable.

Due to the fact that the equipment, located downstream of the reactor, is in operation or in the process of starting, while the reactor is not producing or with low production, it implies an increase in Operating costs, which is never desirable in an industrial level operation. .

In patent application no. WO03029384, the water purifier that scrapes the inner wall of the reactor, this mechanical action prevents plastics and carbonaceous residue from heating up the wall, but does not prevent them from heating up to surfaces where this mechanical contact does not exist between two surfaces, such as the interior of the blower and even the shaft itself. In these locations, deposits of carbonaceous waste will begin to form, which tend to increase in size by accumulation, until they are removed, which implies periodic stops for the removal of the waste, which implies loss of production time and an increase in costs. maintenance.

In the present invention, plastics fall on a bed of sand, which is fluidized, which will promote their separation by the bed of sand, preventing any type of watering and increasing the contact area between the plastics and the sand. The movement of the sand itself erodes the particles of carbonaceous residue, which allows the reactor to operate continuously and under stable operating conditions. This mode of operation makes it easier to scale up, with all the benefits for industrial scale application, saving time, energy and costs.

In the present invention, the inner reactor and the outer reactor are both fluidized with sand, the height of the sand beds being similar in both. Since fluidized sand has a high heat transfer coefficient, the heat transfer between a fluidized bed and the reactor walls can be 20-40 times greater than the heat transfer between a gas and the walls, which allows:

1. Maintain a constant and homogeneous temperature inside the pyrolysis reactor, avoiding the appearance of zones with heterogeneous temperatures, since the sand is at a constant temperature and in constant movement. The diffusion of heat, from the combustion gases from the interior of the exterior reactor to the interior of the interior reactor, is higher compared to that of patent application no. WO03029384.

2. Quickly mix the solids, which makes it operate in almost isothermal conditions, throughout the reactor bed, which allows automatic control of the operation, in a simple and reliable way.

3. Process a higher flow rate of plastics, compared to the reactor of patent application No. WO03029384, since it operates with higher heat transfer coefficients.

The circular distribution box allows uniform distribution of the gases through the perforated tubes, resulting in a uniform fluidization of the outer reactor bed.

pneumatic feeding system is fed by silos that are based on load cells, which continuously control the weight of plastics, allowing a strict control of the flow of plastics fed into the reactor.

Description of the figures

The description that follows is made with reference to the attached diagrams which are presented for reference only, without any limiting character, and in which:

Figure 1 - overall view of the mechanism, in which the various components are identified;

Figure 2 - vertical section of the mechanism, in which the various interior and exterior components of the invention are identified; and

Figure 3 - bottom view of the invention, in which the various components of the same are described.

Legend of the reference numbers - an external reactor (1);

- an external furnace (2);

- a fan (3);

- connecting part (4);

- a circular distribution box (5);

- microperforated tubes (6);

- a main burner (7);

- two gas burners (9);

- two flue gas outlets (10);

- a sand supply tube (11);

- an internal reactor (12);

- a heat exchanger (13);

- an external part where cold water circulates (14);

- pressure gauge tube (15);

- extraction tube (16);

- two tubes (17);

- a refractory lining (18);

- a distributor (19);

- Sand replacement tube (20) from the internal reactor bed (12), during operation; and

- a pneumatic transport mechanism (21).

Description of the invention

The present invention concerns a hydrocarbon production system by pyrolysis of plastic waste in a fluidized bed, as shown in figure 1, which consists of an external reactor (1), an internal reactor (12), two gas burners ( 9) located on the walls of the external reactor (1), an external furnace (2) where the main burner (7) is located, a circular distribution box (5), a heat exchanger (13), a gas compressor and a water cooling system (14).

In addition to the hydrocarbon production system by pyrolysis of plastic waste in the fluidized bed claimed in the present invention, it is also intended to patent in the present invention the method of operation of the hydrocarbon production system by pyrolysis of plastic waste.

As for the hydrocarbon production system by pyrolysis of plastic waste in a fluidized bed, it should be noted that one of the novelties is the use of two concentric and circular reactors, as shown in Figure 2, namely the external reactor (1) and the internal reactor ( 12), in which the external reactor (1) provides heat for the pyrolysis process, with part of the pyrolysis gas being burned in an external furnace (2) to produce hot gases, which will be mixed with outside air through the fan ( 3) reaching about 500-900 ° C.

These hot gases produced in the outer furnace (2) are then used to heat and fluidize the sand bed of the external reactor (1).

The hot gases produced in the outer furnace (2) are transported through a connection (4) to a circular distribution box (5) with microperforated tubes (6), which is located around the external reactor (1).

In this circular distribution box (5), there are microperforated tubes (6) which transport the hot gas to the external reactor (1) and where they inject this hot gas into the sand.

The outer furnace and circular distribution box are made of carbon steel and internal in refractory material (2) _r the outer reactor (1), a (5) and the connection piece (4) covered with a coating (18).

A main burner (7) is located in the outer furnace (2).

This main burner (7) produces gases at 8001200 ° C, which are then cooled to 500-900 ° C using a secondary air introduced into the main burner (7) through the fan (3).

This mixture is introduced into the outer reactor (1) through the circular distribution box (5).

The outer reactor (1) is constructed of carbon steel coated with a refractory lining (18).

In the outer reactor two gas burners (9) walls of the external reactor (1) (1), laterally, there are located in order to raise the temperature of the external reactor (1) to 700-1000 ° C.

The hot combustion gases exit the external reactor (1) from the top through two outlets (10).

The level of the sand bed of the external reactor (1) is maintained at the desired level by supplying sand through a sand supply tube (11) throughout the time of use of the present invention.

internal reactor (12) is where the pyrolysis reactions occur.

In the internal reactor (12) there is no oxygen present and the sand is fluidized in the internal reactor (12) with a part of the gaseous product previously produced and compressed in the process gas compressor and introduced into the sand through two tubes (17) that are attached to the distributor (19) in a microperforated tube. This gas was preheated to about 300-700 ° C, in an exchanger, taking advantage of the heat from the outside reactor gas (1) evacuated to the chimney. The drawings are not shown, the temperature of the internal reactor (12) is kept at 400 -700 ° C.

This internal reactor (12) is constructed of high temperature resistant steel to withstand high temperatures.

The height of this internal reactor (12) is calculated to ensure that the residence time is sufficient and the heat transfer is as desired.

The plastics are fed into the internal reactor (12) through a pneumatic transport mechanism (21).

pneumatic conveying mechanism (21) consists of an annular exchanger (13) in which cold water (14) circulates on the outside and a flow of process gas mixed with the food plastic to the reactor.

water cooling is necessary to prevent plastic softening before entering the internal reactor (12).

There is also a thin tube (15) inserted in the internal reactor (12) at the level corresponding to the top of the fluidized bed to measure the pressure along the bed.

Thus, pyrolysed plastics are basically converted into a gaseous product that leaves the internal reactor (12) through an extraction tube (16) from where it goes to the cooling and condensation system.

The pyrolysis process involves heating the internal reactor (12) through the external reactor (1) so that the internal temperature in the internal reactor (12) reaches a temperature range between 400-700 ° C.

Once this temperature is reached between 400,700 ° C, the plastics are fed to the internal reactor (12) through a pneumatic transport mechanism (21), which, after entering the internal reactor (12), mostly vaporize to produce a cloud of hydrocarbons, which leave the internal reactor (12) and pass through a cyclone, in which all particles are trapped.

From the cyclone, hydrocarbons flow through a tube (not shown in the figures) that is insulated from the outside to a heat exchanger where the gas temperature drops to 200-400 ° C.

From this heat exchanger, the gases pass to the condensers, in which the diesel is used to cool the hydrocarbon gases to around 1030 ° C.

At a temperature of about 10-30 ° C, the condensable part is mixed with diesel and is separated from the non-condensable part.

The non-condensing gases then pass through a cyclone to recover the hydrocarbon vapors and then flow through a heat exchanger, where the gases will be cooled to 10-30 ° C to ensure that the total condensation occurs. .

After passing through another heat exchanger, the gases pass through a compressor in which the pressure will be increased to 200-850 Mbar.

This produced gas, hereinafter referred to as process gas, will then be used for three purposes:

1) To fluidize the sand from the internal reactor, in order to increase the efficiency of heat transfer;

2) To be used in the burners to heat the external reactor to about 700-1000 ° C; and

3) The remainder will be used to generate electricity.

In the liquefaction system there will be a fixed volume of produced hydrocarbons that will circulate in a closed circuit, passing through a cooling exchanger that will maintain its temperature at around 10-30 ° C and will serve to extract heat from the process gases and condense them.

Finally, it should be noted that the quantity in excess of the fixed volume in circulation in the liquefaction system will be sent to the storage, in tanks, of the fuel produced

The present invention should only be limited by the spirit of the claims that follow.

Claims (7)

1. A hydrocarbon production system by pyrolysis of plastic waste in a fluidized bed, consisting of an external reactor (1) that includes two gas burners (9) located on the wall of the external reactor (1) and an internal reactor (12) , characterized in that the external reactor (1) comprises: - a circular distribution box (5) with microperforated tubes (6); - a heat exchanger (13) with a part where cold water circulates (14); - a gas compressor; - a fan (3); - a water cooling system (14); and - a pressure gauge tube inserted in the internal reactor (12) and which measures the pressure along the bed; in which the external reactor (1) and the internal reactor (12) are concentric and circular, with the internal reactor (12), in which pyrolysis takes place, heated by the external reactor (D; and for understanding: - an external furnace (2) where the main burner (7) is located. A hydrocarbon production system by pyrolysis of plastic waste according to claim 1, characterized in that the outer furnace (2), the outer reactor, the circular distribution box (5) and the connection piece ( 4) be made of carbon steel and covered with an internal coating made of refractory material (18). 3. A hydrocarbon production system by pyrolysis of plastic waste according to claim 1, characterized in that the plastics are fed into the internal reactor (12) by means of a pneumatic transport mechanism (21), which consists of an annular exchanger (13) in which the cold water (14) circulates in the outer part of the pneumatic conveyor (14) and in the interior of the pneumatic conveyor (21) a flow of gas from the process passes which mixed with the plastic it feeds to the external reactor (1). 4. Method of operation of the hydrocarbon production system by pyrolysis of plastic waste, described in claim 1, characterized by: - the external reactor (1) supplies the heat for the pyrolysis process, being part of the process gas burned in the outer furnace (2) that produces the hot gases, which will be mixed with outside air through the fan (3) reaching about 500-900 ° C, which are used to fluidize the sand bed of the external reactor (1); - the hot gases produced in the outer furnace (2) are transported through a connection (4) to the circular distribution box (5) which is located around the external reactor (1); - the microperforated tubes (6) of the circular distribution box (5) transport the hot gas to the external reactor (1) where the hot gas is injected into the sand; - the level of the sand bed of the external reactor (1) is maintained at the desired level by supplying sand through a sand supply tube (11) over the entire hydrocarbon production time; - the main burner (7) located in the outside furnace (2) produces hot gases at 800-1200 ° C, which are cooled to 500-900 ° C using secondary air introduced into the outside furnace (2) through the fan (3) ; - the two gas burners (9) located in the external reactor (1) increase the temperature of the external reactor (1) up to 700-1000 ° C; - the gas is preheated to about 300-700 ° C taking advantage of the heat from the combustion gases from the outside reactor (12) evacuated to the chimney through a heat exchanger with the temperature of the internal reactor (12) maintained at maximum at 400-700 ° C; - the pyrolysis reactions take place in the internal reactor (12), in which no oxygen is present and the sand is fluidized with a part of the gaseous product obtained previously compressed in the process gas compressor and introduced into the sand through two tubes (17 ) that are connected to the distributor (19) through the microperforated tubes (6); - the plastics are fed into the internal reactor (12) via a pneumatic transport mechanism (21), previously claimed in claim no. 3; - fed the internal reactor (12), the pyrolysed plastics vaporize to produce a hydrocarbon cloud that leaves the internal reactor (12) through an extraction tube (16) from where it goes to the cooling / cyclone and condensation system ; - from the cyclone, hydrocarbons flow through an insulated pipe outside to a heat exchanger where the gas temperature drops to 200-400C; - from this heat exchanger, the gases pass to the condensers in which the diesel is used to cool the hydrocarbon gases to around 1030 ° C; - at a temperature of 10-30 ° C, the condensable part is mixed with diesel and is separated from the non-condensable part; - the non-condensed gases then pass through a cyclone to recover the hydrocarbon vapors and then flow through a heat exchanger, where the gases will be cooled to 10-30 ° C to ensure that total condensation; and - after passing through another heat exchanger, the gases pass through a compressor in which the pressure will be increased to 200-850 Mbar. 5. Method of operation of the hydrocarbon production system by plastic waste pyrolysis according to the previous claim, characterized in that in the liquefaction system there is a fixed volume of hydrocarbons produced that will circulate in a closed circuit, passing through a cooling exchanger that will maintain its temperature at about 1030 ° C and will serve to extract heat from the process gases to be condensed. 6. Method of operation of the hydrocarbon production system by pyrolysis of plastic waste according to claim 4, characterized in that the excess quantity of the fixed volume in circulation in the liquefaction system is directed to the storage of the produced fuel. 7. Method of operation of the hydrocarbon production system by pyrolysis of plastic waste according to claim 4, characterized in that in the external reactor (1) a hot gas is produced up to a temperature of about 700-1000 ° C , which fluidizes the bed of the internal reactor (12) and feeds the burners that heat the external reactor (1) to approximately 850 ° C and which feeds generators for the production of electrical energy.