WO2021167560A1

WO2021167560A1 - The use of plasma to reduce flue gas emissions in systems working with fossil fuels

Info

Publication number: WO2021167560A1
Application number: PCT/TR2020/051290
Authority: WO
Inventors: İbrahim İBRAHİMOĞLU; Beycan İbrahi̇moğlu; Ziniat İBRAHİMOĞLU
Original assignee: Anadolu Plazma Teknoloji Enerji Danismanlik Arastirma Ve Geli̇istirme Merkezi Sanayi Ticaret Limited Sirketi
Priority date: 2020-02-18
Filing date: 2020-12-14
Publication date: 2021-08-26

Abstract

The invention is related to the recovery heat of with the production of syngas via the transfer of flue gasses released as a result of combustion of various hydrocarbon-containing raw products, especially low-calorie coal, wood, shale gas, plant matter and waste materials such as medical waste, municipal waste, industrial waste, livestock waste with a plasma system to a secondary plasma system, without the gasses in question to become exhaust gasses In particular, the invention is related to the system, which presents a new source of energy by transforming waste gasses released as a result of fuel combustion to purified syngas by mixing the waste gasses with water vapor and purifying it using plasmatron (7), which in turn allows the reduction of harmful gas emissions within the flue gasses formed as a result of the combustion of fuel and the increases energy effiency, and the system is comprised of the main components of a plasmatron (7), which is used to ionize the gasses released as a result of fuel combustion and a mixer (16), which is used to mix the waste gasses formed as a result of combustion with water vapor.

Description

DESCRIPTION

THE USE OF PLASMA TO REDUCE FLUE GAS EMISSIONS IN SYSTEMS WORKING WITH FOSSIL

FUELS

TECHNICAL FIELD

The invention is related to the system and method which allows the recovery heat of with the production of syngas via the transfer of flue gasses released as a result of combustion of various hydrocarbon-containing raw products, especially low-calorie coal, wood, shale gas, plant matter and waste materials such as medical waste, municipal waste, industrial waste, livestock waste with a plasma system to a secondary plasma system, without the gasses in question to become exhaust gasses

In particular, the invention is related to the system, which presents a new source of energy by transforming waste gasses released as a result of fuel combustion to purified syngas by mixing the waste gasses with water vapor and purifying it using plasmatron, which in turn allows the reduction of harmful gas emissions within the flue gasses formed as a result of the combustion of fuel and the increases energy effiency, and the system is comprised of the main components of a plasmatron , which is used to ionize the gasses released as a result of fuel combustion and a mixer, which is used to mix the waste gasses formed as a result of combustion with water vapor.

PRIOR ART

It has become inevitable to obtain energy from fossil fuels due to the increased energy demands of the recent times. Chemical energy released as a result of the combustion of coal and its derivative fuels is transformed into heat energy with various systems, and this energy is then converted into mechanical energy, which in turn is transformed into into electrical energy. One of the most critical problems today is the thermal power plants and the flue gases that are discharged from them, both of which negatively affect the environment and the quality of human life. Generally, low-calorie lignite coals are used in the existing thermal power plants. The usage of lignite coals is almost obligatory to meet the energy demands of the world. In this context, endeavors are being undertaken to make the flue gases released from coal-fired power plants more friendly to the environment. Today, most of the energy demand is met by thermal power plants. One of the main problems experienced with thermal power plants is the release of harmful flue gases to the atmosphere. Emitted flue gases cause environmental pollution and adversely affect human health.

Carbon dioxide emissions are mainly caused by industrial enterprises. Worldwide, such businesses cause an average of 60% of the total C0 released into the atmosphere, while the remaining 40% is caused by the operation of thermal power plants to produce energy. Carbon monoxide and carbon dioxide are combustion products produced in thermal power plants and they are released into our environment, which creates ecological problems. The fact that these exhausted gases cannot be minimized constitutes an important problem.

The problem in the current art is that toxic gases are released as a result of combustion in thermal power plants. These released gases adversely affect nature, environment and human health.

In the systems used in the current art, different filters and flue gas purification systems have been developed for cleaning flue gases. However, due to their high cost and short service life, these types of filters and purification systems are not preferred.

The systems used in the current art cannot be used due to their cost. This situation causes the gases containing carcinogenic particles and harmful emissions to be released to the atmosphere.

In the systems used in the current art, permanency cannot be achieved in preventing flue gas emissions. This situation causes environmental pollution and adverse effects on human health. Another problem in the current art is that the harmful flue gases created as a result of combustion destroy agricultural lands and reduce their production quality with their negative impact on the environment.

Another problem in the current art is that enterprises are subject to criminal sanctions due to their inability to install expensive systems.

As fossil fuels harm the nature and are one of the primary problems of global warming, alternative fuels have started seeing usage and new technologies have been developed to combat the harmful emissions. Therefore, emulsion fuels have become one of the most important research areas in recent years.

Thermal Power Plants

The demand for energy is increasing constantly during these days and it is inevitable and very necessary to obtain energy via fossil fuels. It is also known that thermal power plants, where coal and lignite are used, are becoming widespread in the world. Thermal power plants are systems that convert chemical energy which is generated by combusting coal and derivative fuels, into mechanical energy with certain systems. This resulting mechanical energy then turned into electrical energy through other various systems. The primary equipment of a thermal power plant are: the boiler, the turbine-generator, the condenser and the cooling tower. The boiler is the section where the fuel is burned with various ignition systems to obtain heat. The temperature of boiler varies between 800-2300°C depending on the type of boiler. The heat turns the water around the boiler and in the pipes inside it into superheated steam and sends it to the turbine via appropriate systems. Since steam and water circulate in a closed circuit, the losses are reduced. Combustion gases are given to the chimney at a certain speed after air preheating and filters by giving most of its heat to the boiler.

Losses in a modern thermal power plant are around 61%. These losses consist of losses in the chimney, losses via the cooling tower to the general environment, losses in combustion and thermal losses. The negative effects of coal fuelled thermal plants to the environment are as the following: air pollution, which is the widest-spread environmental effect caused by the waste produced as a result of combustion (SOx , NOx , CO, C0₂ , HF, HCI, Hg, dioxin, tetraphenals, mote emissions, acid rains, etc.), the greenhouse effect that is the result of the emission of greenhouse gasses with C0₂ being the most common culprit, and climate change.

Coal Combustion

Coal consists of two flammable components. These are the volatile substances and the solid (coke) residue. In the first stage of combustion, volatile substances are released. With excessive oxygen coal burns quickly and for a long time, but provides little heat. Then, the coke residue is combusted. The combustion intensity and ignition temperature depend on the degree of carbonization, that is to say, the type of coal (brown, stone, anthracite, lignite). The higher the carbonization degree (highest for anthracite), the higher the ignition and combustion temperatures will be. However, the combustion rate will be as low. Carbon (C) is the primary carrier of heat. When 1 kg of carbon is burned, approximately 34,000 Id of heat is released.

C + 0₂ CO_z

Hydrogen is the second most important element of combustion: When 1 kg of hydrogen is burned, approximately 125,000 kJ of heat is released.

4H + Oz ^ 2HzO

Combustion of 1 kg of sulfur releases 10,000 kJ of heat.

S + Oz SOz

Sulfur is a negative fuel factor. Because S0₂ pollutes the atmosphere, causes corrosion of metals and decreases their quality by interacting with them.

Nitrogen (N) and oxygen (O) are internal organic fuels, and since they are non-combustible, they are only conditionally included in the fuel mass. Increased heat consumption for the evaporation of moisture and the increase in the volume of combustion products (due to the presence of water vapor) reduces the combustion temperature of the fuel.

Ash is a mixture of various mineral substances that are leftover after the combustion of the combustible portions of the fuel. Mineral substances reduce the calorific value of the fuel. The calorific value is equal to the standard value of the enthalpy of the formation of the reaction product

Boiler Ignition

Fuels such as fuel oil and diesel are generally used in igniting the boiler. In these systems, gaseous fuels injected directly to the boiler and combust immediately when coming in contact with air. Air is drawn from the atmosphere and heated. This heated air is transferred to the boiler for the process of combustion. The flue gas temperature resulting from combustion reaches up to 460-550 ° C. The fuel is discharged into the atmosphere at approximately 125-180 ° C with various heat transfer mechanisms, depending on its type and content. Flue gasses are discharged after they are passed through NO_x purification, particle control, and S0₂ purification.

Plasma

Science indicates that there are four states of matter as solid, liquid, gas and plasma. The first three phases make up only 1% of the universe, and these have been researched and learned more or less fully by the researchers, as they are the cornerstones of life in our planet. Plasma occupies a distinct position in this series. It is a source of energy in the open space. Natural scientific researches carried out by scientists for years on end have demonstrated the existence of plasma, which is a mysterious state of matter. Plasma is the most common form of all materials in nature and it constitutes 99% of the universe. The ionosphere, the sun, stars and lightning are all in the plasma state. Plasma is a contemporary technology and it is essentially a renewable energy source. It was first applied in the military field in the 1950s and in sectors such as space, energy, metallurgy, automotive, textile and medicine in the following years. There are various types of plasma such as low temperature, medium temperature, and high temperature. Microwave plasma systems are widely used in the energy field.

Microwave plasma Parallel to high temperatures, the strong ionizing effects of microwave plasma causes complex molecules of carbon-containing materials within the reactor to completely dissociate and ionize. On average, molecules are split into ions at 20% to 80% respectively. By ionizing carbon-containing materials, 95.0-98.0% carbon conversion is achieved via microwave plasma. Most importantly, in the processing of flue gasses which reaches up to 40%, the potential energy of synthesized chemical structures is 105-107 J/cm³. The thermal efficiency of the microwave plasma torch reaches up to 95%.

OBJECT OF INVENTION

In general, the invention in question is related to decreasing harmful gas emissions and increasing energy efficiency of fosil fuel systems which discharge flue gasses as result of the plasma combustion of their fuel, by transferring the flue gasses in question to a secondary unit without exhausting them. With the invention, it becomes possible to obtain a secondary source of heat by producing syngas via injecting flue gasses of thermal plants and other systems which use fossil fuels to the plasma system before they are exhausted and to employ this new source of heat.

The purpose of the invention is to reduce the emission values in the system which uses fossil fuels by having the harmful gasses that are formed as the result of combustion in thermal plants react employing the plasma system.

Another purpose of the invention is the reduction of flue gas emissions by 20% via using plasmatrons for igniting the fuel.

Another purpose of the invention is that it enables the formation of syngas at high temperature by mixing the gases formed as a result of combustion with water vapor and having their ions decompose by using plasmatrons. Another purpose of the invention is to inject the gasses that form as a result of combustion to a secondary unit to use them as a source of heat in the system which uses fossil fuels such as thermal plants.

Another purpose of the invention is to increase efficiency of commercial, agricultural and industrial fields by decreasing harmful gas emissions of systems which use fossil fuels with the use of the plasma method.

Another purpose of the invention is to develop the plasma system, which is more affordable in terms of costs in comparison to expensive filtration and gas purification systems, to ensure that a more efficient and affordable system is being employed.

Another purpose of the invention is the reduction of harmful particles by employing the plasma system, which will also increase effiency and save a significant amount of fuel.

THE FIGURES TO ASSIST IN UNDERSTANDING THE INVENTION

Figure 1 is the drawing of the experimental setup which demonstrates the production of syngas by having the flue gasses produced as a result of combustion in the first section of systems which use fossil fuels injected to the plasmatron in the second section.

Figure 2 is the drawing which demonstrates the combustion of fossil fuels in systems which use fossil fuels with the plasma method.

Figure 3 is the drawing which demonstrates the production of syngas by injecting the flue gasses leaving systems which use fossil fuels into the plasmatron in the second section.

Figure 4 is the drawing which demonstrates the flue gasses leaving the plasma combustion units of thermal plants being injected into the secondary unit and the heating of the second unit with syngas. Figure 5 demonstrates the plasma combustion in one unit of the thermal plant and the transformation of flue gasses produced as a result of this combustion into syngas using the plasma method in the same unit.

S: Water vapor B: Flue gas K: Boiler H: Air Y: Fuel

REFERENCE NUMBERS

1. Floor

2. Cinder Reservoir

3. Reactor

4. Plazmatron Holder

5. Water Inlet Pipe

6. Water Outlet pipe

7. Plasmatron

8. Gas Outlet pipe

9. Thermocouple

10. Insulation

11. Upper Plane

12. Grinder

13. Electric Engine

14. Control System

15. Frequency Inverter

16. Mixer

17. Water Vapor Inlet Field

18. Heat Exchanger The invention will be better understood when explained by referring to the numbers given above and the attached figures.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 provides the drawing which demonstrates the application of the plasma method in systems which use fossil fuels. This system, which reduces the harmful gas emissions in flue gasses, comprises of the following elements: (1) Floor, (2) Cinder Reservoir, (3) Reactor, (4) Plazmatron Holder, (5) Water Inlet Pipe, (6) Water Outlet pipe, (7) Plasmatron, (8) Gas Outlet pipe, (9) Thermocouple, (10) Insulation, (11) Upper Plane, (12) Grinder ,(13) Electric Engine, (14) Control System, (15) Frequency Inverter, (16) Mixer, (17) Water Vapor Inlet Field, and (18) Exchanger

In the invention, the processes of combustion and coal dust ignition are performed using plasma. The flue gases formed as a result of combustion are injected to a second unit without being exhausted. For this purpose, the flue gasses are mixed with the water vapor called "decayed", which leaves the turbines without being discharged. Waste flue gas is mixed with water vapor and injected to the second plasma system. The mixture (flue gas and water vapor) injected to the second plasma system creates syngas at high temperatures via the plasmatron (7).

When the thermal power plants shown in Figure 4 and Figure 5 are analyzed, it can be seen that the process of ignition for the combustion of 1 kilograms of coal is initiated by the injection of 8 to 9 m³ of heated air. As a product of the combustion, carbon-containing constituents such as CO and CO2 are exhausted as flue gas. From carbon-containing constituents such as the exhausted CO and C0 are mixed with water vapor for the purpose of reusage and injected into the plasma system to produce syngas. The syngas produced is used as a secondary heat source. In the system demonstrated in Figure-4, the coal is combusted in the first unit of the thermal power plant and syngas is combusted in the second unit. In a thermal plant employing this system, one unit operates with coal while the other operates with syngas. This system is also used in all combustion systems operating with fossil fuels. In the system demonstrated in Figure-5, coal is combusted at the thermal power plant and the syngas produced using the waste flue gasses are directed into the same thermal plant unit to increase efficiency.

In the system, high temperature plasma with partial ionization method is applied instead of ignition. The combustion process starts with the injection of plasma to the fuel using plasmatrons (7). This ensures that emissions are reduced during commissioning of the boiler. The harmful gas emissions are reduced by approximately 20%.

The powdered coal demonstrated in Figure 2 is transported to the grinder (12) via the operation of the electric engine (13) located on the upper plane (11). The speed and rpm of the grinder (12) is adjusted via the frequency inverter (15) and the control system (14) according to the density of the incoming coal. The powdered coal deposited in the grinder (12) is sent to the reactor (3) mounted on the floor (1). The reactor (3) is covered with insulation (10) to reduce heat loss. Plasmatrons (7) are operated by feeding the coal to the reactor (3). The temperature control of the plasmatrons (7), which are kept fixed by the plasmatron holder (4), is provided by the water circulated by the water inlet pipe (5) and the water outlet pipe (6). Thus, the plasmatrons are cooled. Coal is combusted via the operation of the plasmatrons (7). The cinders formed as a result of combustion is collected in the cinder reservoir (2) to be discharged. The high temperature waste gases released by the combustion of the coal are cooled by the heat exchanger (18) and passed through the gas outlet pipe (8) and transferred to the mixer (16) without discharging them into the atmosphere. The temperature of the gases supplied to the mixer (16) and the temperature inside the reactor (3) are controlled by using the thermocouple (9).

The waste gas entering to the mixer (16) is mixed with the water vapor injected into the mixer (16) through from the water vapor inlet area (17). Water vapor can be the waste steam coming from the turbine or it can be supplied from outside. Water vapor and flue gases are mixed and injected into the plasmatrons (7) shown in Figure-3. With the operation of Plasmatrons (7), the syngas is purified of harmful emissions at a maximum level. High temperature (over 5000 °C) syngas fed from the Plasmatron (7) to the reactor (3) is utilized as a secondary source of heat. Then, the purified syngas inside the reactor (3) is discharged from the reactor (3). The system which uses fossil fuels that is used to reduced the harmful emissions formed as a result of fuel combustion and to increase energy efficiency consists a plasmatron (7) that is used to reduce the emission of waste gases formed as a result of fuel combustion and to ionize the waste gases formed as a result of combustion and a mixer (16) that is used to intake the waste gases formed as a result of combustion and to mix waste gases with water vapor. After the waste gases formed as a result of combustion are mixed with water vapor, they are transformed into syngas by the Plasmatron (7).

In the system which is used to reduce the harmful gas emissions of flue gasses that are formed as a result of the fuel combustion in the system which uses fossil fuels and to increase the efficiency of such systems, the first stage of the process is the delivery of the fuel to the reactor (3), which is followed by the combustion of the fuel by the plasmatrons (7), after which the waste gasses that are formed as a result of combustion is delivered to the mixer (16). Following which, the waste gasses arriving to the the mixer (16) are injected inside the mixer (16) and are mixed with water vapor. After the waste gasses are mixed with the water vapor, the resulting mixture is delivered to the plasmatrons (7) and through the operation of the plasmatrons (7) the syngasses are purified of harmful emissions, and the high-temperature syngasses that is being injected from the plasmatrons (7) to the reactor (3) are used as a secondary sources of heat. In the system which uses fossil fuels, one unit can be operated using solid fuels while the other unit can be operated using the syngas produced off the solid fuels. In the system which uses fossil fuels, the syngas which is produced by mixing flue gasses with water vapor without discharging them and injecting them to the plasma system is delivered to the second unit to ensure that one of the units of the system operates with solid fuels while the other unit operates using syngas. In the system which uses fossil fuels, the flue gasses that are formed as a result of combustion are delivered into the plasma unit before being discharged, which allows them to be used as a secondary source of heat. The water vapor arriving to the mixer (16) can be the water vapors leftover from the steam turbines that are used in fossil fuel using systems, which is also named as decayed.

Claims

1- The invention is a system which works using fossil fuels and it allows the reduction of the harmful emissions of flue gasses that are formed as a result of the combustion of fuel and it also allows the increase in efficiency. The invention's property is characterized in that it comprises of a plasmatron (7) that is used to ionize the waste gasses that are produced as a result of combustion and a mixer (17), which intakes the waste gasses produced as a result of combustion and mixes waste gasses with water vapor.

2 It is a system which uses fossil fuels in accordance with the Claim 1 and it is characterized in that it decreases emission of waste gasses that are formed as a result of combustion by using the aforementioned plasmatron (7) to combust the fuel.

3- It is a system which uses fossil fuels in accordance with the Claim 1 and it is characterized in that the aforementioned plasmatron (7) is used to transform waste gasses that are formed as a result of combustion after the waste gasses are mixed with water vapor.

4 The invention is the method that is used in the system which is used to decrease the harmful emissions within flue gasses that are formed as a result of fuel combustion and to increase efficiency in systems that use fossil fuels and it is characterized in that it comprises of the following process steps:

• delivery of the fuel to the reactor (3),

• ignition of the fuel in the reactor (3) with plasmatrons (7),

• Delivery of the waste gases resulting from combustion to the mixer (16),

• Mixing the waste gases coming into the mixer (16) with the water vapor injected into the mixer (16),

• Delivering the mixture formed after the mixing of waste gases and water vapor to the plasmatrons (7), • Purification of the syngases from harmful emissions by the operation of plasmatrons (7)

• The usage of high temperature syngas fed from the plasmatron (7) to the reactor (3) as a secondary heat source.

5- It is a system that is working using fossil fuels according to Claim 1 and Claim 2 and it is characterized in that, in the system working using fossil fuels, one unit operates using solid fuels while the other operates using syngas derived from the solid fuel.

6- It is a system that is working using fossil fuels according to Claim 1 and Claim 2 and it is characterized in that, in the system working using fossil fuels, one unit of the system can operate using fossil fuels and the second unit of the system can operate with syngas by delivering the syngas that is produced by feeding to the plasma system the non- discharged flue gasses that are mixed with water vapor to the secondary unit.

7- It is a system that is working using fossil fuels according to Claim 1 and Claim 2 and it is characterized in that, in the system working using fossil fuels, the flue gasses that are formed as a result of combustion are fed to the plasma unit and are used as a secondary source of heat without being discharged.

8- It is a system that is working using fossil fuels according to Claim 1 and Claim 2 and it is characterized in that, the water vapor delivered to the mixer (16) is the decayed vapor that is left over from the steam turbine that is used in the fossil fuel using system.