ES2571992B1 - Process and cogeneration plant through the gasification of organic solid materials - Google Patents

Abstract

A process and a cogeneration plant through the gasification of organic solid materials where the high temperature chemical and thermal energy of the resulting combustible gas is used, in which the exhaust gases are conducted to a heat exchanger to transfer heat energy to a thermal fluid, such that the thermal fluid outlet temperature after passing through the exchanger is higher than the thermal fluid inlet temperature prior to the exchanger Said thermal fluid is in fluid communication with an additional heat exchanger that is linked with a Organic Rankine cycle (ORC).

Description

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Process and cogeneration plant through the gasification of organic solid materials

DESCRIPTIVE MEMORY OBJECT OF THE INVENTION

The purpose of this application is to register a process and a cogeneration plant through the gasification of organic solid materials.

More specifically, the invention proposes the development of a cogeneration process through the gasification of organic solid materials where the chemical and thermal energy of high temperature of the resulting combustible gas is used.

BACKGROUND OF THE INVENTION

Gasification is a thermochemical process in which a carbonaceous substrate (organic solid) is transformed into a combustible gas of low calorific value, by means of a series of reactions that occur at a certain temperature in the presence of a gasifying agent (air, oxygen and / or water vapor or mixture of any of the above).

When the gasification is carried out for energetic purposes, the solid waste is transformed into combustible gases of low-medium caloric power which are the ones that are subsequently burned in an internal combustion engine, steam generator or turbine generating energy.

It is scientifically proven that the energy efficiency of gas combustion can be around 10-15% higher than that obtained in the combustion of a solid. On the other hand, from an environmental point of view, gasification is also a cleaner technology, since when carried out under less oxidizing conditions, the production of pollutants such as NOx and SOx is lower.

At present, gasification systems integrated in combined cycles (GICC), applied in energy production plants, are used as a source

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fuel a wide variety of organic solid materials, among which is biomass.

Biomass is a natural resource used since the beginning of time for its energy and environmental advantages. The use of biomass as fuel reduces emissions of pollutants into the atmosphere such as sulfur oxides, carbon monoxides, nitrogen oxides and especially carbon dioxide. In addition, the biomass being a fuel with high carbon content, is ideal for conversion into a gaseous fuel with low-medium calorific value. This process is known as gasification. Biomass gasification is a thermochemical process under an oxygen-reducing reducing atmosphere in which solid fuel is converted into a synthesis gas through a sequence of processes. The calorific value of the synthesis gas is directly related to the operating conditions; election of the gasifying agent, time and speed of gasification, etc.

The gasification plants of organic solid materials produce a gas known as gas of synthesis or "syngas", which is a mixture of carbon monoxide (CO) and Hydrogen (H2). The syngas obtained in these gasification plants have various applications, among which energy production is found, however, usually the produced syngas must be cleaned of contaminants and cooled before it can be used in any subsequent application.

It is precisely in these processes of conditioning of the gas of synthesis or syngas where a residual heat is generated that is wasted as a general rule in the state of the art. In addition, it is also known that there is an accumulation of contaminants present in said gas product of the gasification and that they are not usually used. These pollutants are usually, for example, carbonaceous solids and tars remaining in the current of said gas of synthesis.

In relation to the background of the state of the art, patent no. ES2319026 is

refers to a procedure for the use of glycerin as biomass, for the

obtaining energy in a gas pulverization gasification process, based on

the use of a mixture of oxygen, steam and atmospheric air as gasifying agents,

which are introduced into a gasification chamber at temperatures above 900 ° C, to

that the gas obtained passes to a reformer in which, also at temperatures above

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900 ° C, the set of partial oxidation / thermal cracking reactions is completed in the presence of metal oxides and, subsequently, a hot cyclone is carried out to retain the ashes larger than 5 microns and the gas is cooled sharply through a basket type evaporator.

Also known is European Patent No. EP 0889943 which refers to a fluidized bed reactor system and a method of actuating said system. Said system comprises: a fluidized bed reactor chamber, a particle separator connected to said chamber (to separate the solid material from the exhaust gases) and a gas cooler having cooling surfaces connected to the particle separator. According to this invention, means are provided for separating a flow of solid bed material from the separated material in the particle separator and for introducing said material from the separated bed into the gas cooler. A flow of bed material is separated from the main flow of solid particles, before or after discharging said first flow of solid particles from the particle separator. The separated particle flow is introduced into the gas discharged from the separator during or before cooling said gas, so that said particles mechanically dislodge the deposits from the cooled surfaces.

Another known system is that described in EP1286113 which refers to an apparatus for processing combustible material, comprising: a fluidized bed gasification furnace having a fluidized gas supply means for supplying a fluidized gas in said fluidized bed gasification furnace and to create a flow stream of a fluidized medium within said fluidized bed gasification furnace; means for supplying said combustible material in said fluidized bed gasification furnace to be gasified in said circulation current of said fluidized medium created by said fluidization gas, thereby generating combustible gas and vegetable carbon; and a smelting furnace in which said discharged fuel gas and charcoal are introduced from said fluidized bed gasification furnace and to melt ash to form molten slag.

Another patent document of the state of the art is European Patent No. EP0433547

which refers to an apparatus for gasifying solid fuels, which consists of a

gas producer with a pre-charge silo a carbonization or coking silo and a silo

of gasification and an oven that is especially suitable for gasifying low products

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cost such as wood waste, and chips, solid biomass in general, tires, peat, brown coal, coal, and other materials, and advantageously, solid urban waste.

Lastly, patent No. CN204003297 which refers to a complex energy generation system comprises a solar light collection and heat accumulation system, a biomass gasification device, a gas generator, a steam turbine and a steam generator, in which the solar light captation and the heat collection system is connected to a solar heat exchange system; the biomass gasification device is connected to the gas generator through a gas compressor, a combustion chamber and a gas turbine; The gas turbine outlet is connected to a residual gas heat system; The low pressure steam outlet of the residual gas heat system is connected to the medium and low pressure cylinders of the steam turbine; The high pressure steam outlet of the residual heat system steam and high pressure gas produced by the solar heat exchange system are connected to a mixture of steam and a regulation system; Finally the steam mixture outlet and regulation system are connected to a high pressure cylinder of the steam turbine.

However, there is no knowledge in the state of the art of an efficient fuel gas generation system comprising a gasification plant of organic solid materials with the coupling of an organic Rankine cycle to take advantage of high temperature thermal energy from the processes of thermal cracking and reforming of the gas product of the gasification, to generate energy and to present the additional advantage that it does not generate or accumulate spills of polluting products into the environment.

DESCRIPTION OF THE INVENTION

The present invention has been developed in order to provide a cogeneration process through the gasification of organic solid materials that is configured as a novelty within the field of application and resolves the aforementioned drawbacks, also providing other additional advantages that they will be evident from the description that accompanies continuation.

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It is therefore an object of the present invention to provide a cogeneration process through the gasification of organic solid materials, which comprises the steps of:

- gasification of an organic solid material such that a volume of solid material is transformed into a gaseous state;

- thermal cracking and steam reforming of the gas flow obtained from the gasification in which a thermal fluid is used;

- the filtration of the gas flow from the thermal cracking and steam reforming stage, such that the residual solid particles are separated from the gas flow;

- washing the flow of gas from the filtration;

- the conditioning of the gas flow from washing by means of the condensation in which the thermal fluid is used; Y

- the generation of electric current from at least a part of the flow of condensed gas that generates exhaust gases.

Additional features of the invention are described in dependent claims 2 to 7.

The thermal treatment is carried out in a thermal oxidation chamber at high temperature.

In particular, the invention is characterized by the fact that the exhaust gases are conducted to a heat exchanger to transfer heat energy to the thermal fluid, such that the temperature of the thermal fluid leaving after passing through the exchanger is higher than the temperature thermal fluid inlet prior to the exchanger; wherein said thermal fluid is in fluid communication with an additional heat exchanger that is linked to an organic Rankine (ORC) cycle.

Therefore, the present invention has devised a gasification system that incorporates an organic Rankine cycle (also called "Organic Rankine Cicle" or "ORC"), to maximize the availability of heat present in gaseous streams, making said heat in electric energy to achieve high thermal and electrical performance compared to traditional schemes and also has the advantage that it does not generate polluting spills into the environment.

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Thanks to these characteristics, a system is obtained that takes advantage of the thermal energy from the washing and cooling processes of the gas produced by the gasification, which does not generate or accumulate spills of polluting products into the environment. All this guarantees an increase in the energy efficiency of the cogeneration plant via integrated gasification compared to other facilities for the same purpose, also guaranteeing an efficient management of resources. Another advantageous aspect is the fact that it allows to reduce the environmental impact and that allows to obtain zero spills of polluting products to the environment.

It is well known that the use of Rankine's organic cycle ("Organic Rankine Cicle" or "ORC") uses a heat source to make an organic cooling fluid change its state (vaporization / condensation), taking advantage of residual heat of various industrial processes. Usually the operating temperature is between 70-300 ° C.

It is also another object of the invention to provide a gasification plant of organic solid materials that performs the process described above, comprising:

- A gasification reactor to gasify a fraction of organic solid material;

- A cyclonic particle separator that is in fluid communication with the gasification reactor,

- a cracking reactor for cracking a gas flow from the cyclonic separator that includes a thermal fluid inlet to condition the gas flow and an outlet of the heated thermal fluid;

- a filtering means for filtering the gas flow resulting from thermal cracking that includes an outlet for the extraction of residual materials;

- a washing device for washing the flow of gas from the filtering medium;

- A conditioning medium treating the gas flow by condensation at low temperature;

- An electric energy generating device that is in fluid communication with the conditioning means so that it converts the gas flow into electric current by means of an alternator;

- a heat exchanger that is in fluid communication with the electric power generating device where energy is transferred to the thermal fluid.

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Additionally, the plant includes an organic Rankine cycle (ORC) operating facility that is linked to the thermal fluid linked to the washing device and the cracking reactor through an evaporator device.

Other characteristics and advantages of the process and cogeneration plant through the gasification of organic solid materials object of the present invention will be evident from the description of a preferred, but not exclusive, embodiment illustrated by way of non-limiting example in the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1.- It is a schematic view of a preferred embodiment of a gasification plant of organic solid materials according to the present invention; Y

Figure 2.- is a schematic view of a second embodiment of the gasification plant that includes a Rankine cycle installation with regeneration.

DESCRIPTION OF A PREFERRED EMBODIMENT

In view of the aforementioned figures and, according to the numbering adopted, an example of a preferred embodiment of the invention can be observed therein, which comprises the parts and elements that are indicated and described in detail below.

As can be seen in Figure 1, a plant planned to perform a cogeneration procedure where the high temperature chemical and thermal energy of the combustible gas resulting from the gasification of organic solid compounds has been schematically represented.

This plant comprises a fluidized bed gasification reactor (21) to gasify a volume of organic solid material (1) with the help of a fluidizing agent (air, steam, O2, etc.) (2), a cyclonic particle separator (22) equipped with an outlet (221) for the recirculation to the gasification reactor (21) of carbonaceous solids, a thermal cracking and reforming reactor (23) of the gas produced by the gasification consisting of a thermal fluid inlet (A ) for conditioning the gas flow and an outlet of the same thermal fluid (A1) heated to a temperature between 280-300 ° C.

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The gasification reactor (21) used in the plant described herein may be of the type, for example, as described in WO 2015/040266 belonging to the same applicant.

On the other hand, the thermal cracking and reforming reactor (23) of the gas produced by the gasification can be of the type, for example, as described in WO 2015/059328 belonging to the same applicant.

The gasification plant also includes a filtration means (24) to filter at high temperature (350-450 ° C) the flow of gas resulting from thermal cracking and steam reforming that includes an outlet for the extraction of ashes, tar and solids residual carbonates (c), as well as a washing device (25) for washing the flow of said product gas from the filtration medium that includes an outlet for the extraction of water that has been used to perform the washing step as well as of condensable residual materials (w2).

A conditioning means is also provided to treat the flow of gas from said washing device by means of low temperature condensation (26), a means of conditioning the clean gas to increase its temperature and avoid future condensation (27) which has a thermal fluid inlet (A1) as a heating source and an outlet of the same fluid (A2) (180-240 ° C) and electric power generation device (28) in fluid communication with the conditioning medium that converts the flow of gas in electric current (E) through an alternator (29) (of a known type so that it will not go into greater detail in its description). A water treatment plant (70) is arranged to allow the separation of condensable materials (701) from the process water (w1) for reuse in the washing unit (25) mentioned above.

Exhaust gases (281) at high temperature (480-500 ° C) generated in the electric power generation device (28) are taken to a chimney, previously passing through a heat exchanger (30A) where a transfer takes place of an energy to the thermal fluid (A2) so that it results in a stream of hot thermal fluid (A31) that is at a temperature in a range between 280-300 ° C.

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Ace! The plant itself has a thermal oxidation chamber (50) fed with a fraction of the gas stream (91) before it enters the electric power generation device (28) and where the residual currents of ash and carbonaceous solids (c), condensable liquids and wastewater (701) for thermal treatment, producing a flow of exhaust gas (501) at elevated temperatures, approximately 900-1000 ° C, than in an exchanger Heat transfer (30B) transfers energy to the thermal fluid (A) to result in a stream of hot thermal fluid (A32) at a temperature of approximately 280-300 ° C. Said thermal oxidation chamber (50) also has an outlet (502) provided for inert ash output.

The thermal fluid flow rate heated to a temperature of 280-300 ° C is directed to a thermal fluid storage tank (61) in order to homogenize properties and through the heat exchanger (80) it is able to transfer the thermal energy exchanged to return to the system at the operating temperature (140 ° C), that is, back to the cracking reactor (23).

Additionally, the plant integrates an installation based on an organic Rankine cycle (also called "Organic Rankine Cicle" or "ORC"), linked to the thermal fluid used in different stages of the procedure for the generation of electric energy that allows maximum utilization of the availability of heat present in the gas flows, converting said heat into electric energy. In the embodiment of Figure 1, this Rankine cycle installation comprises a hydraulic circuit provided with a turbine (90) for the reception of a flow of thermal fluid from the heat exchanger (80), generating electric current (92), a condenser (91) that receives the thermal fluid flow from the turbine, the fluid flow being pumped by a pump (CP3).

On the other hand, in a second preferred embodiment, where the same parts have the same numerical references, it differs from the previous embodiment in the fact that the hydraulic circuit includes an organic fluid regenerator that is in fluid communication with the turbine (90 ) and the condenser (91), such that the flow of thermal fluid is directed to the heat exchanger (80) from the regenerator (92).

The details, shapes, dimensions and other accessory elements, used in the

Fabrication of the plant of the invention may be conveniently substituted by others.

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that do not depart from the scope defined by the claims that are included below.

Numerical References:

1. Solid fuel organic matter

2. Fluidizing agent

3. Gas flow from the gasifier

4. Gas flow leaving the cyclonic particle separator

5. Flow of gas leaving the cracking reactor

6. Gas flow leaving the filtering stage

7. Gas flow leaving the washing stage

8. Gas flow leaving the condenser

9. Reheated gas flow

21. Gasifier or gasification reactor

22. Cyclonic particle separator

23. Thermal cracking and steam reforming reactor

24. Filters

25. Station or washing area

26. Capacitors

27. Gas reheater

28. Internal gas combustion engine

29. Alternator

30A Heat exchanger for engine exhaust

30B. Heat exchanger for exhaust gases from the chamber

oxidation

50. Oxidation chamber

60. Additional air cooler

61. accumulator deposit

70. Process water treatment station

701. condensable liquids and wastewater

80. Evaporator or evaporator device

81A and 81B. Organic fluid that is part of the ORC cycle

90. Turbine

91. Condenser

92. Organic fluid regenerator

221. Recirculation of solid particles

281A and 281B. Engine cooling water

5 A, A1, A2, A3, A4, A5. Thermal fluid

C. Ash mass and carbonaceous solids from the gas flow CP1, CP2, CP3. E1 and E2 pumps. Electricity produced

W1 and W2. Water flow

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Claims (9)

5 10 fifteen twenty 25 30 35 1. Cogeneration process through the gasification of organic solid materials (1), which includes the stages of: - gasification of an organic solid material (1) such that a volume of solid material is transformed into a gaseous state; - thermal cracking and steam reforming of the gas flow obtained from the gasification in which a thermal fluid is used; - the filtration of the gas flow from the thermal cracking and steam reforming stage (5), such that the residual solid particles are separated from the gas flow; - washing the flow of gas from the filtration; - the conditioning of the gas flow from the wash (7) by means of the condensation in which the thermal fluid is used; Y - the generation of electric current from at least a part of the flow of condensed gas that generates exhaust gases; characterized by the fact that the exhaust gases are conducted to a heat exchanger to transfer heat energy to the thermal fluid, such that the temperature of the thermal fluid leaving after passing through the exchanger is higher than the inlet temperature of the previous thermal fluid to the exchanger; wherein said thermal fluid is in fluid communication with an additional heat exchanger that is linked to an organic Rankine (ORC) cycle; Y in which a fraction of the gas flow after conditioning and solid residual particles from the filtration undergo an additional stage of thermal treatment, carried out in a thermal oxidation chamber, producing exhaust gases that exchange heat with the thermal fluid that is in fluid communication with the ORC cycle. 2. Process according to claim 1, characterized in that the exhaust gases are at a temperature between 900-1000 ° C. 3. Process according to claim 1, characterized in that the filtering step is carried out at a temperature between 350-450 ° C. 4. Process according to claim 1, characterized in that the thermal fluid that is linked to the thermal treatment and thermal fluid that is linked to the stage Additional heat treatment are in fluid communication in a storage medium. 13 5 10 fifteen twenty 25 30 5. Process according to claim 1, characterized in that the temperature of the fluid linked to the conditioning of the gas flow from the wash after a heat exchange with the gas flow leaves at a temperature between 180-240 ° C. 6. Gasification plant of organic solid materials, comprising: - A gasification reactor (21) intended to gasify a fraction of organic solid material; - A cyclonic particle separator (22) that is in fluid communication with the gasification reactor, - a thermal cracking and steam reforming reactor (23) for cracking a gas flow from the cyclonic particle separator (22) that includes an inlet of thermal fluid to condition the gas flow and an outlet of the heated thermal fluid; - a filtering means for filtering the gas flow resulting from thermal cracking (5) that includes an outlet for the extraction of residual materials; - a washing device for washing the flow of gas from the filtering medium; - A conditioning medium treating the gas flow by condensation at low temperature; - An electric energy generating device that is in fluid communication with the conditioning means so that it converts the gas flow into electric current by means of an alternator (29); - a heat exchanger (30A) that is in fluid communication with the electric power generating device where energy is transferred to the thermal fluid; characterized by the fact that an organic Rankine cycle (ORC) operating facility is linked to the thermal fluid linked to the washing device and the thermal cracking and steam reforming reactor (23) through an evaporator device ( 80). 7. Gasification plant according to claim 6, characterized in that the cyclonic particle separator (22) is provided with an outlet for the recirculation of carbonaceous solids from the gasification of organic matter in the direction of the gasification reactor ( twenty-one). 8. Gasification plant according to claim 6, characterized in that the organic Rankine cycle operation installation (ORC) comprises a hydraulic circuit provided with a turbine (90) for receiving a thermal fluid flow from a heat exchanger and a condenser (91) that receives the flow of 5 thermal fluid from the turbine (90) and pumping means. 9. Gasification plant according to claim 8, characterized in that the pumping means comprise a discharge pump. 10 10. Gasification plant according to claim 8, characterized in that The hydraulic circuit includes an organic fluid regenerator (92) that is in fluid communication with the turbine (90) and the condenser (91), such that the thermal fluid flow is directed to the heat exchanger (80) from the regenerator ( 92).