WO2009020442A1

WO2009020442A1 - Solid fuel gasification and gas cleaning system

Info

Publication number: WO2009020442A1
Application number: PCT/TR2007/000122
Authority: WO
Inventors: Huseyin Yamankaradeniz; Mustafa Tolay
Original assignee: Detes Maden Enerji Ve Cevre Teknoloji Sistemleri Limited Sirketi
Priority date: 2007-08-03
Filing date: 2007-10-10
Publication date: 2009-02-12
Also published as: TR200705430A2

Abstract

The invention relates to a system for gasification of solid fuels such as coal, lignite, petro coke, dangerous solid wastes, domestic solid waste, industrial solid waste, biomass covering wood charcoal, wood wool, wood shaving, agricultural wastes, treatment sludge, leather wastes, leather industry treatment sludge and cleaning of the produced gas. The solid fuel gasifier comprises: a drying zone (2.1); a pyrolysis zone (2.2); a first gasification zone comprising an oxidization zone (2.3), a reduction zone (2.4); a strait zone (2.5); a screen zone (2.13); a second oxidation zone (2.14). Furthermore the system comprises an ash extraction system (2.15) and a wet discharge system (2.7) where the ash is extracted from the water bath. The system comprises also an elaborate gas cleaning unit (3).

Description

SOLID FUEL GASIFICATION AND GAS CLEANING SYSTEM TECHNICAL FIELD

The invention relates to a system for gasification of solid fuels and removal of produced gas. Coal, lignite, petro coke, dangerous solid wastes, domestic solid waste, industrial solid waste, biomass covering wood charcoal, wood wool, wood shaving, agricultural wastes, treatment sludge, leather wastes, leather industry treatment sludge are gasified.

PRIOR ART

Gasification is performed in the gasification reactors prepared in the form of fuel bed where solid fuels contact oxidants (air, oxygen, steam or various mixtures of them) Gasification reactors are classified as updraft or downdraft fixed bed, fluid bed and integrated bed depending on the use of gas fuel. Although fluid and integrated gasification beds are strong and functional for gasification, since, in general the design, construction and operation of them is expensive, they are not recommended for small scaled operations (1 MWe). On the other hand, being considerably common in poor countries because of particularly simple design and construction, fixed bed gasification beds are also convenient in terms of investment, operation and maintenance costs.

Generation of combustible gasses such as poor gas types of synthesis gas (syngas), air gas, city gas from solid fuels is a chemical process known as gasification.

If to make a comprehensive definition of gasification; it is the process of converting the carbonaceous and hydrogenous solid fuels into gas product of convenient heating value. Definition of gasification cannot be called exactly as full combustion nor such definition consists of processes such as pyrolysis, partial oxidization, reduction and hydrogenization.

The first technological applications known in regard to gasification mainly are based on pyrolysis; (for example, application of heating to supply materials in non-oxygen ambient). Today pyrolysis is not as important as before, and the mostly applied technology is partial oxidization providing generation of synthesis gas from solid fuels. The said synthesis gas composes of methane, hydrogen, carbon monoxide as combustible components in varying rates as well as oxygen, nitrogen and water. The gasification process realized by means of partial oxidization is not only applied to coal, wood, solid wastes and similar solid fuels but also can be applied to solid, liquid and gas supply materials such as waste oil and natural gas. Although pyrolysis is considered as an intermediate step for transition to mining technologies, it is also associated with gasification which is partial oxidization and is deemed as intermediate reaction in solid waste gasification. Hydrogenation has obtained a unique place in the process of development of gasification technology, and this process is also called as hydro-gasification or hydrogenation gasification. More efficient electric and heating energy can be generated by means of gasification instead of generating energy as a result of combustion of solid fuels. In addition, direct burning of solid wastes to discard them is not preferred as it cannot be employed as an adequate power source and causes additional air pollution.

Conversion of solid wastes into electric and heating by means of gasification of them today is preferred for both reasons namely, high energy and no environmental problems. Although source of solid wastes is limited, it is essential as it is a sustainable and renewable power source when compared to hydrocarbon fuels which are finishing. In the future, gas fuel to be generated from gasification of solid wastes can also be commonly used in the places where natural gas is used as an additional fuel and most of the power can be supplied from this fuel. Solid wastes can be easily used as substitute of hydrocarbon fuels because of the environmental problems caused by hydrocarbon fuels as well as potential energies of it.

Gasification is a technology known since end of 18th century. Particularly for the developing countries, since then it has been proved that biomass and solid wastes playing a role from today to future can be used. Another matter which is known is that solid wastes used as power source has several disadvantages. If the solid wastes having low power density (about 1000-1500 kcal/kg) are burnt directly, the efficiency is too low and it causes high level of air pollution in indoor and outdoor locations. Fuel oil gasifiers are advantageous in terms of fixed investment, and operating costs when compared to power generated by use of classical burning techniques in terms of power efficiency. The setting-up costs of the system as design of gasification reactor is comparable to plants where electric energy is generated from conventional waste (WtE) (is cheaper) and the reason is that electric energy effectiveness of such systems is 50% grated than the conventional WtE plants, all costs related to waste treatment considerably decreases. The results of one of those techno-economic studies has indicated that gas generation from waste systems is more effective than those of modern WtE plants and in addition investment and operational costs are less [2,3,4,17,18,19]. When the success achieved in KAG (Solid Waste Gas) during last decade, it is seen that there is scientific information shortcoming in gasification process and gas removal. However, a few have resulted in advancement, success, operating pilot plants and demos. Despite this, just few projects have achieved commercial success in the market where the technology has competitive advantage.

Obtaining biomass sources is more expensive than obtaining hydrocarbon source. However, being a renewable source biomass is an essential component of the sustainable global power. In addition to this, green house gases decreases in emission and carbon cycle and supports green industry with rural economy development.

Where gasification gas is used, solid wastes are converted into gas combustible with thermal cycle technology by means of gasification. Gasification occurs with partial oxygen, air, steam or reaction of them with solid waste. The generated gas consists of carbon monoxide, carbon dioxide, hydrogen, methane, ethylene, propylene, water and nitrogen as well as wastes such as carbon particle, ash and tar. Following cleaning of the generated gas, it is used in steam boilers, gas engines, gas turbines to generate heat and power. The gasification technique produces a gas fuel from biomass, which can be used in petrol operated turbines generating power and thermal at high efficiency. The cleaned gas fuel generated by means of gasification from biomass is directly burnt at thermal and steam generating boilers or used in Stirling engines for electric generation at 20-30% efficiency. Electric generation can be provided at compressed gasification turbines at 40% or higher efficiency.

Tar and particulates should be cleaned in order to burn the generated gas in internal combustible engines. The combustible content of the generated gas is mixture of varying rates of mainly carbon monoxide, hydrogen and hydro carbon gases (varies depending on raw material) and nitrogen. The nitrogen content in the gas composition generated with gasification reaction is more when compared to other gases and therefore, thermal value of the gas is low (1800-2000 kcal/m³). Tar is the side products known as non-burnt carbon particles and ash. The power content of the generated gas is suitable for use in internal combustible engines, boilers and furnaces but the gas containing nitrogen is not recommended for medium and long transportation. In order to provide full capacity burning in solid waste gasification, when pure oxygen or steam is used instead of air, gas of high power intensity can be generated. Although the thermal value is low, it has been started to gasify solid wastes in gas engines and turbines, electric generation or internal combustible engines and to use it as power source. With this method, the usable and modernized gas fuels can be used as conventional fuels of less harmful emission releases. Gasification is known as use of solid biomass energy. Gasification Thermodynamics:

Gasification is the thermo chemical conversion process wherein gas fuel is generated from solid fuel, solid waste or biomass. In other words, such solid fuels and biomass is converted into gas fuel through thermo chemical conversion. The aim of the modernized carbon source power technologies is to decrease rate of emissions during production and use and thus to increase intensity of the fuel. The solid fuel provided in the gasifier as raw material is usually of a very complicated structure, and a theory for potential fuel types at a wide range is validated.

Gasification consists of mainly volatilization, pyrolysis, burning and reducing reactions with the effect of temperature. For that reason, reaction thermodynamic is studied by focusing on pure carbon simply as done by several researchers while establishing the gasification theory. Approach of gasification of the carbon contends materials accepted for solid fuels can be adapted for partial oxidization of gases such as natural gas. While discussing the theoretical infrastructure of any chemical process both thermodynamics (for example, the status of the process in a given time and under pressure circumstances for a certain time) and kinetics (e.g. the direction of development and now long will it take) should be studies. Gasification process occurs at temperature of 800⁰C to 1300⁰C. The certain temperature depends on supply material features, particularly softening and melting points of the ash. However, the said range of temperature is adequately high for modeling the gas compounds and carbon (if considered to be graffiti) according to thermodynamic balances, and it constitutes the foundation of several industrial reactor designing as the values close of real are obtained. This situation is unconditionally suitable for all fixed bed gasifiers and can even be applied to several fluid bed and traveling bed gasifiers. However, it should be known here that the supply material is theoretically carbon and hydrogen source. In the said thermodynamic modeling, use of carbon as supply material in traveling bed gasifier suggests some exceptions such as movement of oxygen and steam in reverse direction towards fuel. In such gasifiers, the pyrolysis reaction occurs in cold upper parts of the reactor and for that reason, it is not suitable to formulate a simple definition for the said part of the reactor by prediction of thermodynamic balances. Whereas, the steam/oxygen and carbon reaction occurring in hot lower part of the reactor can be easily defined based on thermodynamic balances. A second exception is for the biomass gasification occurring at 850°C. Gasification theory is limited for gasification reactions at 85O⁰C and higher. For modeling in regard to occurrences under 850⁰C , there are pyrolysis reactions constituting big difficulties and partial oxidization reactions occurring very slowly and having small practical values. Thermodynamic studies should be made considering all those assumptions,

Impacts of features of solid wastes on gasification:

First of all features of solid waste to be gasified should be very well known for selection of gasification process. Moisture, ash, fixed carbon and volatile agent contents and activity of solid waste briquette element analysis, grain size, caking property and ash melting temperature have all significant effects on the gasification. a) Moisture: Gasification is applied in fixed bed gasifiers provided that moisture does not exceed 15% and ash content 20%. If the moisture content of the solid waste exceeds this value, pre-heating is required. High moisture content in fluid bed systems helps water vapor supplied for gasification. But in such case, the system should be provided with heating. b) Ash: Solid wastes giving high amount of ash causes problems during gasification. The higher the ash rate the less the amount of combustible material to be gasified; and therefore, gasification efficiency decreases. In addition, gasification of the solid waste becomes difficult and it becomes impossible after a certain ash rate. Excess ash causes decrease in capacity of reactors. c) Volatile agent: During heating process applied in gasification process of solid waste briquette, the solid waste briquette firstly looses its volatile content. The volatile agents mixed with the gasses produced during the process causes increase in total gas product amount. The hydrogen in the volatile agent content combines with the carbon in the coal and forms methane and even ethane. Tar and oils can also increase the efficiency of the process. d) Melting temperature of the Ash: The highest temperature of the burning area of the fixed bed gasifiers should be under melting point of the ash.

Solid waste Gasification Reactions: Solid fuels such as coal, wood, lignite and solid waste briquette used for gasification contain carbon, oxygen, nitrogen, sulphide and hydrogen as element. The gasifiers providing gasification convert carbon sources such as solid fuel into gas under high temperature. Main chemical reactions occurring during gasification of the solid carbon in the form of coal, coke or wood coal contain carbon, carbon monoxide, carbon dioxide, hydrogen, water (water vapor) and methane. Also hydrocarbon and tar derivatives such as ethylene, propylene are also formed in small amount.

Gasification of solid wastes consists of some steps. First of all, solid wastes are converted into suitable briquette or pellet. Removal of water in the solid waste is conducted during preliminary processes. Converted into briquette or pellet and containing 10-15% water content in general, the solid waste converts its water into steam phase inside the gasifier. Upon drying process, the pyrolysis, reduction, burning and similar reactions occur. Biomass of solid waste containing more than 35% of water is not convenient for electric generation with thermo chemical conversion. 8-15% of moisture rate is convenient for gasification and pieces of 50- 100 cm size are deemed as ideal. In general 10% of moisture rate is preferred for gasification reactions. The water in the solid waste is used to produce water vapor required for water vapor reaction which is one of the gasification reactions, and this reaction is highly significant. Because the carbon monoxide gas in the poor gas to be generated is generated by this reaction.

For starting the gasification process, a part of the carbon element in the solid waste briquette is burned and thus firstly water is passed into steam phase, then pyrolysis phase and gasification reaction temperatures are achieved. Drying, pyrolysis, carbonization, degradation and burning reactions occurring in gasifier are described in details below respectively.

Stage I: Drying; Vaporization of Water Solid fuels contains higher rate of water than other fuels. The water content of solid waste briquette is in the form of surface water remained on the surface of the fuel or hygroscopic moisture kept in the porosity of the fuel. Particularly if this rate is high in the briquette obtained from solid wastes, gasification reactions do not occur. Because temperature of gasification reactions cannot reach 1000-1200⁰C since the energy to be needed for vaporization of the excess water will be obtained from the incarnation energy of the solid waste briquette. Otherwise, the energy obtained from incarnation reactions is spent on vaporization of the excess water. The solid waste briquette involved in gasification firstly gives its water and water passes into gasification environment in vapor form to realize water gas reactions. Stage II: Pyrolysis

Pyrolysis is the chemical decomposition of organic materials by heating in the absence of oxygen. During the heating up to 500-600⁰C in the absence of oxygen, gas components, volatile and non-volatile condensable agents known as tar, wood coal type materials known as fixed carbon and ash occurs. When high temperature is reached, the gas compounds and char gas is released.

Pyrolysis process develops as following: mixed organic molecules are decomposed in the temperature range of 400°C-600°C , and separated into much smaller molecules by means of decomposition with distillation, polymerization, condensation reactions, and converted into combustible and non-combustible gases and tar derivatives. Pyrolysis occurs at short term reactions at medium temperatures. At the end of pyrolysis, biomass of 75% weight, tar of 12% and gas of 13% occur. The following theoretical reactions develop in the pyrolysis process and big molecules are decomposed by heating. The gas compositions released as a result of pyrolysis process are: 50% CO₂, 35% CO , 10 CH₄ %, 5% other hydrocarbons and H₂. Liquid products are liquefied part and tar.

C₆H₁₀O₅ + Heat = C_nH_mO_y

In addition, a third step independent of degradation reaction at high temperature occurs. The energy needed for this reaction step is supplied by the energy released at oxidization step, As a result of the reaction, high molecule agents are decomposed to lower molecules and carbon monoxide.

Stage III: Degradation (Gasification)

The process up to about 500⁰C in gasification of the organic agents is phase of pyrolysis wherein carbon, gases (calorific value of up to 20 MJ/m³) and tar are obtained. When the temperature reaches 1000⁰C, carbon reacts with water vapor and CO and H₂ are generated. Additional oxygen input may not be needed for gasification process depending on variable oxygen rate in the raw material. What is important in gasification is that the moisture rate of biomass does not exceed 30%. The higher the moisture rate the lower the calorific value of the gas. In addition, when amount of combustible gas CO decreases in volume, the amount of CO₂ increases. If the agent existing at 1000⁰C in the gasifier contacts with water vapor, water gas is obtained. As seen below, the most suitable temperature for water gas generation is 1000⁰C. Table-1 :Quantities of CO, CO₂ and H₂ at increasing temperatures

t (temperature) (⁰C) % CO %CO₂ % H₂

400 0.2 33.1 66.6

600 19.2 200.3 60.5 800 46.1 2.6 51.3

1000 49.5 0.3 50.3

The following reactions occur at 1000⁰C:

C + H₂O > CO + H₂ (Δ H= +31.35 kcal/mol) (Water gas reaction)

C + 2H₂O > CO₂ + 2H₂ (Δ H= +22.5 kcal/mol)

CO + H₂O > CO₂ + H₂ (Δ H= -9.85 kcal/mol) In this case, the first two reactions are endothermic. The first reaction dominates the method and the third one is a semi-reaction. Reaction heating is met by carbon burning. The third reaction is exothermic and at 0⁰C and 1 atm, ΔH= -9.85 kcal/mol. When the number of mole in the reaction is equal to the resulting, the pressure has no impact on chemical conversion. For occurrence of CO in gasifier, the carbon layer should be thick, penetrable and hot enough. In the reaction zone, the oxygen of the sent air and carbon and hydrogen react arid the following reactions occur on the surface of the carbon particulates:

C + O₂ > CO₂ (Δ H= -94.09 kcal/mol) CO₂ + C > 2CO (Δ H= +41.16 kcal/mol) (Boudouard reaction) C+ 2H₂ «- CH₄ -17.90 kcal/kmol (Methanisation Reaction)

Furthermore. In the spaces of the particulates:

CO + !4O₂ > CO₂ (Δ H= -67.63 kcal/mol) reaction occurs. As a result, CO₂ is formed mainly in the burning zone described below.

Conversion of CO₂ into CO occurs in degradation zone. C + CO₂ > 2CO (Δ H= +41.16 kcal/mol)

In addition in gasifier, H₂, CH₄, CO₂, H₂S and SO₂ in small amount also occur in addition to CO. Composition of a typical poor gas obtained from solid waste is ; 11% H₂, 20% CO, 3% CH₄, 55% N₂, 10% CO₂, 1 O₂% and other ethylene and propylene. Resulting carbon monoxide and hydrogen are converted into carbon monoxide and hydrogen subject to a second treatment which is a degradation reaction as per the reactions. In addition to this, non-burnt carbon and tar also occur and solid waste converted into tar is gasified. The resulting gases are combustible gases and particulate agent concentration in the product decrease.

C₆Hi₀O₅ + O₂ > C_xH₂ + C_nHmOk + CO + H₂ + heat

The reaction equations listed above are reduced to two homogenous equation below.

CO Conversion Reaction: CO+ H₂O ÷- CO₂ + H₂ -9.8 kcal/kmol

Vapor Methane Conversion Reaction:

CH₄+ H₂O ÷- CO + 3H₂ +49.28 kcal/kmol

When mole and heat effects of the above reactions are examined, it is defined that solid fuel containing carbon and hydrogen can be gasified. When carbon is gasified, it plays an essential role in obtaining CO. Water gas and hydrogenation reaction is the basis of gasification treatment. However, several gasification processes are based on the balance between partial burning and water gas reaction. Comprehensive reaction for real fuels can be formulated as follows.

C_nHm +n/2O₂ = nCO + m/2 H₂ Wherein;

For gas being pure methane, m=4 and n=1, therefore, m/n=4 and For liquid fuel; m/n ~2, therefore m=2 and n=1 and For coal and solid waste; m/n~1 , therefore, m=1 and n=1.

Stage IV : Burning Reactions:

The carbon (C) and hydrogen (H) elements of biomass formed from solid waste briquette releases heating energy upon oxidization according to the above reactions. Such reactions are exothermic reactions where heat is given out. They convert into carbon dioxide and water vapor respectively. Ash containing the inorganic minerals not burnet as a result of burning and gasification reactions also occurs. Burning reactions of carbon and hydrogen in solid waste with partial oxygen are as follows theoretically. Since free oxygen all reactions under gasification conditions exist fully, burning reactions should not be mentioned in definition of synthesis gas composition balance.

C+1 /2O₂=CO + Heat -26.55 kcal/kmol

00+1/2O₂=CO₂ + Heat -67.70 kcal/kmol H₂+ 1/2O₂= H₂O + Heat -57.90 kcal/kmol Fixed Bed Gasifiers

Fixed bed gasifiers are divided into four types namely down flowing, up flowing, counter flowing and open flowing according to air and fuel inlet direction.

Down flow gasifiers have fuel input from the above and air from below. Sizes, forms and moisture content of biomass particulates should be kept within the specified limits. The quality of produced gas is generally good. They are convenient for 1 MW and less electric capacity systems. Biomass is dried and moisture content is reduced under 20% for a good gasification process. The gas produced at high temperature (700⁰C) is separated from gasifier. The advantage of down flow gasifiers is that the tar in the produced gas is at very little quantity.

While the biomass in up flow gasifiers moves down, the gas flows up. Such gasifiers are convenient for tens of megawatt electricity capacity systems. The sizes, forms and moisture content of biomass particulates are more flexible when compared to down flow gasifiers. They are of simple design in general and produce high ash and moisture content and less quality gas. Since the gas consists of 10-20% volatile oils (tar), they are not convenient or use in engines and turbines.

Table-2: Features of raw material to be used in fixed bed gasifiers

Type of gasifier Up flow Down flow Open flow Counter flow

Fuel Wood Wood Brass shield Coal Size (mm) 20-100 5-100 1-3 40-80

Moisture, % <25 <60 <12 <7

Ash, % <6 <25 About 20 <6

In down flow gasifier, the air enters from the special air supply part located in the down part and solid fuel and gas flows down in the same direction. When solid fuel enters the gasifier, the moisture starts to dry. This part is the drying zone of the gasifier. The temperature in drying zone is about 200⁰C. The dried solid fuel moving down reaches the pyrolysis zone. The temperature of this zone is about 600⁰C. Solid fuel starts to decompose in this zone and organic molecules are decomposed and production of tar starts. While thermal decomposition occurs on one side, chemical conversions occurs on the other side and solid fuel also starts to undergo deformation. The solid fuel undergoing pyrolysis reactions and thermal deformation starts to produce CO, H₂, CH₄, CO₂ and light hydrocarbon molecules in oxidization and reaction zones located further down. The main gas generation part of the gasifier is this zone. The only remaining part from the solid fuel completely converted into synthesis gas theoretically is the ash which cannot be converted. However, both shortcoming of the gasifier system and raw material differences lead to failure to fully gasify. For that reason, although low quantity of tar is provided in particularly the down flow gasifiers, it fails to continuously operate due to faults of mechanical, constructional design. In addition, it has been failed to generate fully clean gas due to shortcomings in the cleaning stages of synthetic gas generated in gasification systems[2,3,4,7,23,24,25_I26,27].

One of the disadvantages of the down flow gasifier type is that the capacity of the unit is limited. When higher capacity is required, several units are operated. Another disadvantage is that it has higher moisture and ash content and total efficiency is lower. Blocking may occur because of shortcoming in construction of ash removal systems. Since the gasifier does not have gas emission system, gas emission pipes can be blocked by ash, soot etc. Gas cleaning systems are not effective. Since the gas is only tried to be flushed with distilled chemical solvent and filtered by means of polymer type filters, the tar and soot coming with the gas covers the surface of the polymer filters immediately and gas cleaning line is out of order and the system fails to operate. The tar coming with the gas consists of hundreds of organic compounds and therefore divided into certain classes. Known as tar entirely, those compounds are classified into six main classes namely heavy tar, light tar, wet tar, tar consisting of aromatic and aliphatic light compounds, water solved tar, compounds consisting of BTX, tar containing ammoniac compounds. It is not likely to clean the tars from gas by means of water flushing containing chemical solvents. Gas cleaning systems of the said down flow type gasifiers are not able to clean the tar completely. The synthesis gas which is end product contain tar since all of the known types of tar cannot be cleaned, and the tar causes problem in gas engine or gas turbine while burning the gas. Gas cleaning system is the most important part of gasifiers and must be highly advanced in respect to tar cleaning. The gas cleaning systems provided before are not effective, and their operation is not likely in terms of technology either. Ash extracting systems are in the form always causing problems. The system has to stop in case of agglomeration, sintering , clinkering in the ash.

OBJECT OF THE INVENTION

From the known status of the related art, the purpose of the invention is to develop a solid fuel gasification and gas cleaning system which can be used in gasification of any solid wastes such as coal, lignite, petro coke, dangerous solid wastes, domestic solid wastes, industrial solid wastes, biomass covering wood waste, wood chips, wood chipping, agricultural wastes, treatment sludge, leather wastes, leather industry waste sludge and is alternative to fixed bed down flow gasification reactors.

Another purpose of the invention is to prevent occurrence of supply or feeding problems by means of operation of solid fuel supply unit free of problems. Integration of the solid fuel supply unit with entire system automation provides full automatic operation of the system.

A further purpose of the invention is to prevent problems such as overflowing, missing that might occur in regard to raw material in the system by help of controlling the raw material level in the solid fuel gasifier.

Another purpose of the invention is to provide gasification reactions at ideal gasification temperatures between 1000°C-1200⁰C by means of process control and automation and thus provide low tar production and the most convenient synthetic gas mixture.

Another purpose of the invention is to provide supply of air to gas by means of saving in the heat near the gasification since the oxygen needed for gasification is supplied from the air, and to develop a unique system having feature of the highest efficiency in terms of power and heat economy.

Another purpose of the invention is to ensure the required reactions of the materials being source for carbon and hydrogen loaded into gasifier by means of air inlet ducts and enable realization of gasification in full efficiency. A further purpose of the invention is to prevent occurrence of gas leakage into external environment and take the system under full safety by means of operation of the solid fuel gasifier and gas cleaning unit under atmospheric pressure. Since the system is under vacuum, unique safety at maximum level is provided.

Another purpose of the invention is to provide vibration since automation of the system is fully provided in the gasifiers, and prevent the blocking that might occur in the system because of properties of the raw materials by means of operations such as ash mixtures.

Another purpose of the invention is to prevent ash and soot clogging in the gas output pipes by means of preliminary dust separator and dust separator cyclone of the produced raw gas provided around the solid fuel gasifier in order to prevent the clogging of soot, ash, grains in the solid fuel gasifier.

A further purpose of the invention is to prevent occurrence of agglomeration, sintering, clinkering problems in the ash by means of ash emission system, ash analysis in the ash fuel and temperature controls conducted continuously. Another purpose of the invention is to prevent pressure loss, gas leakage and air leakage in the solid fuel gasifier as the ash is flowed into water in the ash emission system.

Another purpose of the invention is to provide production of combustible gas of carbon and hydrogen content in the most economical and easy way. The said combustible gases are generally CO, H2,CH₄. A further purpose of the invention is to provide optimum level of gasification of solid wastes particularly enriched and converted into briquette and pellet..

Another purpose of the invention is to provide cleaning of harmful gases, all tar derivatives such as dust, ash, heavy metal, metal oxides, H₂S, HCN, ammoniac existing in the gas generated in the solid fuel gasifier and thus ensure operation of gas cleaning line and system free of problem.

Another purpose of the invention is to provide heat insulation and metal material wearing in solid fuel gasification zone by means of internally coating the gasification part of the solid fuel gasifier entirely or in partial with heat insulation material depending on type of the solid fuel.

Another purpose of the invention is to develop a solid fuel gasifier and gas cleaning system preferred to down flow gasifiers for internal combustible engines of which gas quality has been proven with easy to operate feature and commercialized best solid fuel gasifiers due to the most reduced tar problem in raw material.

Another purpose of the invention is to develop a environmentally friend solid fuel gasifier and gas cleaning system having shorter duration required for ignition and temperature to operate at proper gas quality (20-30 minutes) than down flow gasifiers, having technical structure and automation without any explosion risk. In order to achieve the said purposes, a solid fuel gasification and gas cleaning system for gasification of solid fuels such as coal, lignite, petro coke, dangerous solid wastes, domestic solid wastes, industrial solid wastes, biomass covering wood waste, wood chips, wood chipping, agricultural wastes, treatment sludge, leather wastes, leather industry waste sludge and cleaning of produced gas, consisting of a solid fuel feeding unit feeding briquette or pelleted solid fuels into the system

- a solid fuel gasifier consisting of a drying zone providing vaporization of the water content of the solid fuel pellet or briquette, a pyrolysis zone located on the lower part of the said drying zone, wherein solid fuels are subjected to thermal deformation at temperature range of 400°C-600°C and decomposed into coke, char, tar, CO, CH_4, and H₂, an oxidization and reduction zone located on lower part of the said pyrolysis zone, wherein oxidization and reduction reactions are realized at temperature range of

1000°C-1200⁰C with heated air and organic compounds and char compounds having all high molecule weight of the pyrolysed solid waste are oxidized and reduced and decomposed into CO, H₂, CO₂, CH₄ and light hydrocarbon of very light molecule weight, a strait zone located on the lower part of the said reduction zone where the obtained solid fuel gas and ash

. are conveyed, a screen zone located on lower part of the said strait zone, a second oxidization zone where the said screen part combines with partial air once more and the remaining char is oxidized,

- an ash extraction system located on the lower part of the said solid fuel gasifier, an extraction and mixing apparatus preventing agglomeration and sintering that might occur in the ash during gasification and wet discharge system into which the produced ash is discharged.

- Gas cleaning unit consisting of dust separator cyclones providing cleaning of impurities such as dust, soot, ash grains, tar derivatives, H₂S, HCN, dioxan, furan and water, and trapping dust particulates existing in raw gas leaving the solid fuel gasifier, wet gas flusher where heavy char in raw basis in the gas, soluble char and chemical agents such as H₂S, HCN are passed through flushing solution and cleaned, wet solvent pool located on the lower part of the wet gas flusher, wherein collected char and dust particulates are accumulated in form of soil upon agglomeration, oily gas flusher wherein light char derivatives, char derivatives in form of aromatic and aliphatic structure not soluble in water, BTX aromatic compounds are passed through grease, flushing oil tank located on lower part of the said oil gas flusher wherein the accumulated tar are accumulated, sand filters used to recycle water solvents and oil solvents used in wet gas flusher and oil gas flusher, wet electrostatic precipitator wherein liquids, dust particulates, heavy metal particulates, acid fogs, smokes, dioxan or furan compounds of aerosol in micron size are electric loaded and providing holding in the water saturated gas, a gas emission fan providing gas emission from the system and pressure decrease, gas storing tank providing supply of produced cleaned gas into gas burning line without floating in gas supply and procuring the required gas amount in case of various stops, gas conditioner which filters the dust particulates remaining in synthetic gas produced and cleaned in solid fuel gasifier and provides required moisture to the gas, gas cooling / heating part where the temperature adjustments and moisture adjustments of the gas from gas conditioner are provided.

In order to achieve the said purposes, the solid fuel pellets or briquettes are in 80 - 110 mm diameter and 100-150 mm long. In order to achieve the said purposes, the solid fuel pellets or briquettes are of 10- 15% of the moisture rate in weight.

In order to achieve the said purposes, the said solid fuel gasifier consists of an inner region coated fully or in partial with refractory material depending on type of solid fuel. In order to achieve the said purposes, the solid fuel supply unit consists of one valve air locking system,, solid fuel silo and weighing system.

In order to achieve the said purposes, it consists of a level control system located on the solid fuel gasifier and providing control of solid fuel level.

In order to achieve the said purposes, it consists of a vibrator located on the solid fuel gasifier and providing vibration.

In order to achieve the said purposes, it consists of at least one pre-heating chamber located on the lower part of the solid fuel gasifier, heating the incoming air and taking the heat from solid fuel gasifier wall.

In order to achieve the said purposes, it consists of at least one air inlet chamber connected to the second oxidization zone and providing heated air.

In order to achieve the said purposes, it consists of at least one nozzle providing convey of air into solid fuel gasifier.

In order to achieve the said purposes, it consists of at least one air inlet duct located on the strait zone and supplying the heated air. In order to achieve the said purposes, it consists of at least one control valve providing control of air inlet.

In order to achieve the said purposes, it consists of a pre-dust separator located around the solid fuel gasifier. In order to achieve the said purposes, it consists of at least one gas output pipe located on the pre-dust separator.

In order to achieve the said purposes, it consists of rotary valve and air locking system located on lower part of the dust separator cyclones and removing the dusts trapped in the holder cyclones and supply of it into ash emission system. In order to achieve the said purposes, it consists of wet electrostatic precipitator, one gas inlet part, one gas flushing and wetting part, one filter, one electrostatic precipitator and gas output.

The structural and characteristic features and all advantages of the invention will be better understood with the detailed description with the figures given below and referring to the figures and for that reason, the assessment should be made taking into consideration the figures and detailed description.

BRIEF DESCRIPTION OF THE FIGURES

Figure -1 is the schematic view of the solid fuel gasifier and gas cleaning system. Figure - 2 is front view of the solid fuel gasifier. REFERENCE NUMBERS 1. Solid fuel supply unit

1.1. Valve air locking system

1.2. Solid fuel silo

1.3. Weighing system 2. Solid fuel gasifier

2.1. Drying zone

2.2. Pyrolysis zone

2.3. Oxidization zone 2.4. Reduction zone

2.5. Strait zone

2.6. Inner zone

2.7. Wet discharge system 2.8. Air inlet ducts

2.9. Control valve

2.10. Vibrator

2.11. Air pre-heating chamber

2.12. Nozzle 2.13. Screen part

2.14. Second oxidization zone

2.15. Ash extraction system

2.16. Extraction and mixing apparatus

2.17. Level control system 2.18. Air inlet chamber

2.19. Pre-dust separator

2.20. Gas output pipes 3. Gas cleaning unit

3.1. Dust separator cyclones 3.1.1. Rotary valve

3.1.2. Air locking system

3.2. Wet gas flusher 3.2.1. Wet solvent pool

3.3. Oil gas flusher 3.3.1. Flushing oil tank

3.4. Sand filter 3.5. Wet electrostatic precipitator

3.5.1. Gas inlet part

3.5.2. Gas flushing and moistening part

3.5.3. Filter 3.5.4. Electrostatic precipitator

3.5.5. Gas output

3.6. Gas emission fan

3.7. Gas storing tank

3.8. Gas conditioner 3.9. Gas cooling / heating part

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a system for gasification of solid fuels and cleaning of the produced gas. The solid fuel gasification process developed under the invention can be defined as conversion of partial oxygen source into combustible gas product (combustible gas) under heat application with a solid carbon containing material (raw material). Figure -1 shows schematic view of the solid fuel gasifier and gas cleaning system.

Solid Fuel Supply Unit (1):

If the solid fuels to be used in solid fuel gasifier (2) are not in the appropriate grain size, they are converted into pellet or briquette of 80-110 mm diameter and 100-

150 mm length. After the domestic wastes (DW) are enriched and converted into fuel briquette or pellets produced from the waste, they can be used in solid fuel gasifier (2). Under the scope of the invention, solid wastes such as coal, lignite, petro coke, dangerous solid wastes, domestic solid wastes, industrial solid wastes, biomass covering wood waste, wood chips, wood chipping, agricultural wastes, treatment sludge, leather wastes, leather industry waste sludge are gasified.

The solid fuel used under the invention contains moisture of 10 - 15% in weight. The moisture amount is needed for hydrogen production as required by the water gas reaction. The solid fuel to be used may contain inorganic material in rate of 10 - 15%. The said inorganic materials form ash as a result of gasification. Such inorganic materials of the solid fuel not gasified consist of materials such as lass, metal, sand etc. which will form ash. Solid wastes are enriched and can consist of materials of 3500 - 4000 kcak/kg lower thermal value. As an example, the solid waste compound consisting of combustible compounds can be in the form of (lower sum of gasifiable rate %: 94.0%), paper and cartoon (45.8%), plastic waste (25,2%), organic (10.8%), hygienic materials (5,6%), textile waste (3,4%), wood etc. (3,4%), leather (0,6%) and inert inorganic materials known as ash in general (lower sum: 6,0%), glass (0,7%), metal (0,6%), other inorganic material (3,9%).

After drying and briquette operation, solid fuel briquette or pellets of 80 110 mm diameter are fed into solid fuel gasifier (2) from solid fuel feeding unit (1) . However, distilled raw material is never fed into solid fuel gasifier (2).

Solid fuel feeding unit (1) mounted on the solid fuel gasifier (2) consists of a valve air locking system (1.1), solid fuel silo (1.2) and weighing system (1.3), and depends on automation. Solid fuel gasifier (2) contains one level control system (2.17) controlling solid fuel level and vibrator (2.10) located on solid fuel gasifier (2) providing vibration.

Solid Fuel Gasifier (2): Figure -2 shows front view of the solid fuel gasifier (2). Solid fuels reaches drying zone (2.1) of the solid fuel gasifier (2) located on the upper part. Since the maximum temperature in drying zone (2.1) is about 250⁰C, solid fuel is dehydrated firstly in this zone and such water content is immediately vaporized.

Pyrloysis zone (2.2) is located under the drying zone (2.1). Pyrolysis zone (2.2) extends down to strait zone (2.5) in shape of conic. Pyrolysis cone (2.2) and inner zone (2.6) of the solid fuel gasifier (2) is coated with refractory material entirely or in partial depending on type of solid fuel. The purpose of it is to provide heat insulation and protect the inner zone (2.6) against high temperatures and temperature changes as it is in the coal gasification. Solid fuels reaching pyrolysis zone (2.2) in dried and heated to 250⁰C start to be subject to thermal deformation and convert into tar, CO, light hydrocarbons. The temperature of the pyrolysis zone (2.2) is about 400°C-600°C. Solid waste reaching this zone starts to be subject to thermal deformation, shape deformation and thermo-chemical, thermo-physical changes. In particular, it is decomposed into coke, char, CH₄, and H₂ in great amount. For gasification the solid fuel must be of features providing solid-gas contact and of gas penetration and this feature is provided by the solid fuel gasifier (2) developed under the invention.

The solid fuel meeting the oxygen at 600⁰C in pyrolysis zone (2.2) starts to give the first low temperature reactions and reaches oxidization and reduction zones (2.3, 2.4) which is lower part and provides main gasification. Heated air inlet ducts (2.8) are located on strait zone (2.5) in two lines. The heated air coming from air inlet ducts (2.8) goes in reaction with pyrolysed solid fuel of first oxidization. Air inlet is provided by an air inlet duct (2.8) and control valve (2.9). The coming air flows into nozzles (2.12) through air pre-heating chamber (2.11) obtaining its heat from solid fuel gasifier (2) wall. While both oxidization and reduction reactions occur in the upper part of this strait zone (2.5), the temperature must be around 1000°C-1200⁰C. Thus at temperature of 1000°C-1200⁰C, organic compounds, tar compounds of high molecule weight having pyrolysed solid waste are decomposed and converted thermo-chemically and oxidized and reduced and converted into CO, H₂, CO₂, CH₄ and light hydrocarbons having very light molecule weights.

Particularly, the reaction conducted at 1000°C-1200⁰C to produce H₂ by water vapor is essential in such reactions. For that reason, initially 10-15% of moisture is required in the solid fuel.

Solid waste reaching strait zone (2.5) has been fully gasified and converted into ash, and the produced solid waste gas has temperature of 1000°C-1200°C, and mainly CO, H_2, CO_2, CH₄ are produced. The gas passing through screen part (2.13) made of metal durable against heat in strait zone (2.5) combines once more with partial air in second oxidization zone (2.14) on lower part of the strait zone (2.5) and the finally remaining are oxidized here. The conical part providing connection of the second oxidization zone (2.14) with ash collection area and providing separation from air inlet chamber (2.18) is made of special steel material and is coated with refractory material if required. There is an additional air inlet chamber (2.18) here to provide heated air.

Air inlet is provided by one air inlet duct (2.8) and control valve (2.9). The air is supplied to lower nozzle (2.12). Tars and other non oxidized and not converted into gas parts flowing in the gas undergo a final oxidization. Such nozzles (2.12) are used when required. Such utilization depend on type of the solid fuel and composition of obtained gas.

Thus, solid fuel is subject to conversion in a great amount and leaves the solid fuel gasifier (2) as synthetic gas. Pre-dust separator (2.19) surrounding the solid fuel gasifier (2) like a jacket extending through and over the ash is a component completely unique to the invention. In the systems provided before, the gas output part is located just near the strait zone (2.5) and therefore, gas pipe section may encounter narrowing due to ash and soot clogging in the strait zone (2.5).

Under the scope of the invention, the gas leaving the pre-dust separator (2.19) enters into dust separator cyclones (3.1) of the gas output pipes (2.20) in upper part and flows towards gas cleaning unit (3).

Table-3: Brief analysis value of some solid fuel types

Sample Moisture Volatile Ash Lower thermal

Fixed materia value Carbon I (kcal / kg)

Solid waste 10 40 35 15 3.500 briquette%

Wood 17 63 17 3 4.440

Grain husk 16 59 21 4 4.120

Rice husk 30 48 16 6 3.840

Lignite 34 29 31 6 3.600

Coal 11 35 45 9 6.000

Table-4: Analysis values of some solid fuel derivatives (non-moisture, without ash base) Sample C (%) H (%) O (%) N (%] I S (%)

Solid waste 53,0 8,0 31.5 6,0 0.4 briquette %

Wood 51.6 6.3 41.1 0.6 0.4

Grain husk 49.5 7.1 42.5 0.5 0.4

Rice husk 50.8 6.7 41.5 0.5 0.5

Coal 76.1 9.8 10.5 1.9 1.7

Lignite 68.9 6.8 22.4 1.2 0.7

Ash Extraction System (2. 15) and Sinter Breaker:

There is an ash extraction system operating in different form under solid fuel gasifier (2). Ash extraction system can be helical type or conveyor type depending on type and character of the fuel. Ash extraction system (2.15) of solid fuel gasifier (2) operating under atmospheric pressure must also operate under atmospheric pressure. For that reason, regardless of operating type of the ash extraction system (2.15), the extracted ash has to be discharged into wet discharge system (2.7). Both metal conveyor ash extraction system (2.15) and metal helical ash extraction system have to operate under atmospheric pressure in a manner not disturbing the reactor pressure. The ash obtained from ash extraction system (2.15) contains not converted carbon particulates in too little amount. The ash obtained can be used as raw material in asphalt production material or cement production. [6, 7, 20, 23, 24]. Ash extraction system (2.15) is also a special design not leaking gas and allowing air passage. The structure of the inorganic materials present in solid fuels in general changes depending on type of the fuel. When solid fuels such as coal and particularly lignite is used, the ash structure of such materials can be different. Particularly, if inorganic structure of the ash contain Na, K compounds in high rates, since the fusion temperature of such ash can are lower, in case of point temperature increases during gasification, agglomeration and sintering may occur in the ash. Sintering and agglomeration in the solid fuel causes different structure of the ash particulate size and even existence of big size clinkered and sintered ash cakes. In order to eliminate such occurrence, regardless of type of the solid fuel used as raw material in gasification, inorganic chemical structure of the ash must be considered and monitored. The following table shows solid fuel types in different ash inorganic structure and particularly ash melting temperatures. This topic can be seen in a previously conducted study on agglomeration and sintering of ash contents in solid fuels.

The vibrator (2.10) and extraction and mixing apparatus (2.16) located on the solid fuel gasifier (2) developed under the invention eliminates the agglomeration and sintering problem that might occur in the ash during gasification. One of the important criteria of the invention is that monitoring of chemical structure of the ash and sintering in the ash are prevented.

Table-5: Analysis values in ashes of different solid fuels (% weight)

Sample SiO₂ AI₂O₃ CaO MgO Fe₂O₃ Na₂O K₂O Ash softening temperature ⁰C

Solid 54,0 12,0 17,0 2,6 9,4 2,2 2,8 1500 waste

Coal 35,7 17,0 11,5 5,1 6,2 7,2 0,9 1220 (Gδynϋk) Coal 44,5 3,2 4,3 1,3 17,3 0,9 0,2 1400 (Can) Wood 54,0 12,0 17,0 2,6 9,4 2,2 2,8 1600 Gas Cleaning Unit (3):

Raw gas cleaning unit (3) is used to clean raw gas from solid fuel gasifier (2), impurities therein such as any dust, ash particulates, tar types, H₂S, HCN, dioxan, furan and water. Such contaminants must be cleaned from the gas. Particularly, the tar causes problems in gas engines and gas turbines where gas is burned to generate electricity and can also cause air pollution in flue gas occurring as a result of burning of the gas during heat energy generation. Thus use of clean synthetic gas is provided in gas engine, gas turbine or burning systems where cleaned synthetic gas is used.

For that purpose, a series of pollution cleaner mainly dust separator cyclones (3.1), wet gas flusher (3.2), ail gas flusher (3.3), flushing ail tank (3.3.1), water solvent pool (3.2.1), sand filter (3.4), gas emission fan (3.6), wet electrostatic precipitator (3.5), gas storing tank (3.7) clean the gas in gas conditioner (3.8). In order to understand completion of gas cleaning process, a series of gas analysis is conducted by means of gas analysis systems.

Dust separating process firstly starts from pre-dust separator (2.19) located around the solid fuel gasifier (2). Not existing in previous gasifiers this feature provides a pre-dust separation in the solid fuel gasifier (2) developed under this invention and prevents clogging of gas output pipes (2.20) and thus helps gas cleaning unit (3). The dust particulates, ash, soot, gasified carbon particulates separated in pre-dust separator (2.19) are conveyed into ash extraction system (2.15). Dust particulates existing in raw gas leaving the solid fuel gasifier (2) move to dust separator cyclones (3.1) via pipes extending from pre-dust separator (2.19) of the solid fuel gasifier (2). Dust separator cyclones (3.1) has the design of classical cyclonic dust separator and the dust kept in conic lower parts of the two dust separator cyclones (3.1) are removed out by means of rotary valve (3.1.1) and air locking system (3.1.2) and sent to ash extraction system (2.15) [7,23,24].

In addition to ash particulates, particulates consisting of non gasified solid fuel and in general carbonized and called soot, H₂S, HCN₁ NH₃ gases, ammoniac water etc. listed among pollutant components of gas, tar is also particularly important. Tar is organic chemicals not fully gasified as a result of gasification reactions. For that reason, it is important in gasification studies and gas cleaning.

Importance and Cleaning of Tar in Solid Fuel Gasification:

Tar is a mixture of chemical agents consisting of black, bad odor, aromatic and aliphatic hydrocarbons. It is a bit heavier than water. It contains aromatic hydrocarbons and their derivatives and oxygen, nitrogenous sulphide aromatic compounds. It consists of 2-8% light oil, 8-10% medium oils, 8-01% heavy oils, 16-

20% anthracene oil and 50-55% heavy tar. Light oils is a mixture obtained at temperatures of 70-170 ⁰C and consisting of 50-55% benzene, 5-10% benzene homolog (toluene, xylene), 10-15% naphthalene, 10-12% acid compounds

(phenol), 1-3% base (pyridine etc.) and sulphur compounds. Middle oil is a mixture obtained at the temperatures of 170-230⁰C and consisting of 33-40 % naphthalene, 15-25 % acids (phenol), 5 % base (pyridine). Heavy oil is mixture obtained at the temperatures of 230 - 270 ⁰C and consisting of mainly naphthalene, anthracene, high molecule cresols and xylenol and pyridine derivatives. Anthracene oil is a mixture obtained at the temperatures of 270-360⁰C and consisting of anthracene, phenanthrene, high phenols and base.

In order to clean the tar occurred during gasification and conveyed to gas cleaning unit (3), it should be cleaned by use of appropriate cleaning techniques in the form of firstly heavy tar and water soluble cationic, anionic characterized tar and light characterized tar. Since tar compound contains hundreds of different classes of chemical agents, it is likely to classify these chemical agents at certain intervals and dissolve them from gas. For that purpose, the tars of high condensation temperature, water soluble are separated from the gas immediately in the water flushing system and can be separated in the form of caked with dust and ash particulates. The wet gas flushers (3.2) described below are used for this purpose. With this water flushing system not only heavy precipitated tar materials but also chemicals such as H₂S, HCN, NH₃ present in the gas are flushed with alkali water solvent and can be separated from gas.

Then tar types of light density and soluble in grease oils are contacted with grease oil in oil gas flusher (3.3) and light tars are separated from the gas. Other impurities remaining in the produced gas are separated in the wet electrostatic precipitator (3.5). The said physical and chemical processes are directly related to condensation temperature and chemical properties of the tar. For that reason, gas cleaning unit (3) selected according to such properties for tar separation are unique and sole [30,31,32,40].

During each gasification process, hydrocarbons, heavy aromatic materials, light aliphatic and aromatic oils, different organic compounds can be produced. In particular, the fact that aromatic and aliphatic organic compounds called tar occur in an adhesive form adhered to ash and soot grains in output of solid fuel gasifier (2) causes cover of an adhesive agent inside the pipe and other equipment of the gas cleaning unit (3). This impact will lead to covering thereof in a manner leading to damage on mechanical part of the gas engine or gas turbine if gas is not cleaned. The contaminants conveyed with tar and having corrosive impact should also be cleaned. As it has been tried to be explained above, it is obvious that the contaminant factors in the gas must be cleaned. The tar and ash and sand grains as adhered to the tar clog all filters of the gas engine and gas turbine in a short time, and also cause blocking in engine cylinder and similar mechanic parts. In short, any and all contaminant factors existing in the gas, grains of size bigger than micron level, acidic compounds, compounds of corrosive impacts, gases such as H2S, HCN, NH₃ , harmful chemicals such as dioxan, furan, heavy metals, any tar types and organic chemicals should be cleaned from the synthetic gas not only for system security but also for environmental requirements. In addition, the tar cleaned from the gas can be used again in solid fuel gasifier (2) as side product and sold.

Gas flushing systems:

After removal of dusts from raw synthetic gas produced and existing in the solid fuel gasifier (2), raw gas flows to wet gas flusher (3.2) and oil gas flusher (3.3) divided into two parts and operation in serials.

Wet (Water) gas flusher (3.2):

Wet gas flusher (3.2) relates to water and chemical flushing. The former flushing usually consists of heavy tar in raw base, water soluble tar and chemical agents such as H₂S, HCN flushable and extracted with water chemical agent solvent. The gas is supplied to wet gas flusher (3.2) through a vortex. The flushing is realized by means of spraying the flushing solvent in the wet gas flusher (3.2) and atomized form spraying the gas and flushing solvent in opposite current. In general wet chemicals, flushing solvent of alkali feature and heavy tar, water soluble aromatic tars materials such as H₂S, HCN and an amount of conveyed dust particulates are collected and accumulated in the water solvent pool (3.2.1) located under the wet gas flusher (3.2). The tar and dust particulates collected here are provided with the feature of accumulation on the water surface in form of cake as agglomerated with water. Then the tar accumulated on the surface of water solvent pool (3.2.1) and lighter than water are removed with an upper scrapper and can be recycled to solid fuel gasifier (2) as fuel via an appropriate pumping system. The water solvent accumulated in water solvent pool (3.2.1) are flushed in sand filters (3.4) and then upon filtering are sent back to water gas flusher (3.2) for use. The gas flows to oil gas flusher (3.3) after this stage.

Oil Gas flusher (3.3): Synthetic raw gas not only contains heavy tar types, water soluble tar types but also BTX, light tar types and aliphatic and aromatic tar types of low molecule weight not water soluble. Oil gas flusher (3.3) of similar feature to wet gas flusher (3.2) but containing grease oil instead of water is used for separation of tar types of low molecule not water soluble but grease oil soluble from the gas. Grease oils are sprayed toward gas from center of oil gas flusher (3.3) and sent in atomized form and thus the most convenient gas oil contact is provided and thus light tar types in the gas, non water soluble aromatic and aliphatic tar types, BTX aromatic compounds are separated from gas and accumulated in the flushing oil tank (3.3.1) located under the oil gas flusher (3.3). Such tars accumulated therein are used as fuel in solid fuel gasifier (2) by means of an appropriate supply system.

Great amount of all contaminants existing in synthetic raw gas coarsely are flushed and cleaned. However, the gas still contains contaminants in mist form and wet electrostatic precipitators (3.5) are used to clean them. Filters:

Separate sand filters (3.4) are used to regain the water solvent and oil solvents used in both wet gas flusher (3.2) and oil gas flusher (3.3) For that purpose, the filter called tandem consists of sand filter (3.4) for water storing system wet gas flusher (3.2) or similar filter systems, and oil tandem filter system consists of similar sand filter (3.4) or similar filter system

Wet Electrostatic Precipitator (3.5):

After the produced gas are cleaned of contaminants such as dust, ash, tar and H₂S, HCN etc in a great amount in order to prevent any problems in gas engines or gas turbines where they are burned, they are passed through a final wet electrostatic precipitator (3.5) I so as to clean all impurities that might remain. It is not likely to remove the impurities of the liquids, dust particulates, heavy metal particulates, acid fogs, smokes, dioxan or furan compounds in the form of aerosol in micron size by means of charging electric by wet electrostatic precipitator (3.5). For that reason, wet electrostatic precipitator (3.5) holds such micron sized contaminants in the gas saturated with water. The micron sized gas reaching longer part of the wet electrostatic precipitator (3.5) is saturated with water and thus positive charge is applied to walls of the precipitator while the contaminants loaded onto water particulates pass through the electrostatic area, the particulates are negative load loaded and collected and flows downward by gravity force. The wet electrostatic precipitator (3.5) separates the particulates from the gas at an efficiency of 99.9%. High ionization occurs on the wires between poles of wet electrostatic precipitator (3.5) and it provides separation of the particulates. The panels where particulates are collected are always water flushed and therefore, the collected and gathered particulates flushed downward. Thus wet electrostatic precipitator (3.5) operates much more effectively than other precipitators and cleans the last contaminants remaining in the gas. Since cold water is passed through the panels where particulates are accumulated, tar type particulates are accumulated without vaporization.

Since condensing points of tar compounds vary between 130⁰C and 21⁰C because of composed o hundreds of different aromatic and aliphatic organic compounds. For that reason, cleaning of such complicated chemical agents may cause problems and wet electrostatic precipitator (3.5) provides solution to such problems. Tar types can be cleaned easily from gas and wet electrostatic precipitator (3.5) can be very easily used as they are not effected from high voltage.

Wet electrostatic precipitator (3.5) 28 to 37 kV can be applied between wire and panels therein and the period of gas staying there is between 4 to 11 seconds. The foam occurrence on the panels of wet electrostatic precipitators (3.5) is ignorable and it is of continuous operating feature for 200 hours. If flushing is conducted at wet electrostatic precipitator (3.5) at certain times, the impurities are cleaned [6,7,23,24,29]. Specially designed wet electrostatic precipitator (3.5), wet gas flusher (3.2) and oil gas flusher (3.3) are main characteristics of the invention and are used for the first time under the scope of the invention. Wet electrostatic precipitator (3.5) can operate isothermally at ambient temperature, is effective with its capability to operate at high voltage and convenient period of gas staying. The effectiveness of the wet electrostatic precipitator (3.5) depends on temperature, pressure, voltage, gas flow, gas composition, quantity and tar type.

Wet electrostatic precipitator (3.5) consists of gas inlet part (3.5.1), gas flushing and moistening part (3.5.2), filter (3.5.3), electrostatic precipitator (3.5.4) and gas output (3.5.5), namely five parts. Such a wet electrostatic precipitator (3.5) operates at 99,9% efficiency and provides full opacity in gas and holding the grains less than 0.01 size at low pressures. Thus, even the metal oxides in the gas can be trapped.

The electrodes located in the wet electrostatic precipitator (3.5) prevent clogging. In addition, it has a simple, durable, maintenance free design. Wet electrostatic precipitator (3.5) can be added to any existing wet scrubber in order to increase and enhance particulate removal affectivity to meet zero opacity. The affectivity of the wet electrostatic precipitator (3.5) is to remove the dust and condensable tar drips from the gas. Gas location period of 4 seconds is adequate to remove all tar. Inner part of the wet electrostatic precipitator (3.5) is not subject to contamination. Cleaned product gas is of the feature to protect the equipment against tar and deformation with dust causing failure in ignition of the gas engine.

Wet electrostatic precipitator (3.5) developed under the scope of the invention operates on the same principle as the one of tubular and multi-stage electrostatic precipitators. In the multi-stage design, the particulates are collected in the cell attacking them electrically in the ionization part (consists of plates and wires) and are electrically drawn to earthed parallel plates in the accumulation part. In the tubular design, the plates in the accumulation part are replaced with an "egg case" network consisting of electrically earthed triangle tubes. One of the triangle tubes consists of one electrode extending alongside the tube parallel to earthed walls and central lines randomly located along the tube. When the particulate starts flowing through the tube, the electrode acts as if it is negative loaded. Pushing powers (depending on load similarities) do not effect each other between the electrode and particulate, the traction power between the particulate and earthed walls (earthed walls are of "opposite load" of the particulate load) causes particulate to move towards the walls where particulate collection occurs. This "pushing-pulling" effect is under high accumulation effectiveness of the electrostatic precipitators and less power needs. [6,7,23,24,29].

Characteristics of Wet electrostatic precipitators (3.5): Solid electrodes almost eliminate maintenance unless there is a broken wire requiring replacement. Wider space alongside tubular location considerably decreases problems in ignition and narrowing in the cells. Therefore, this design decreases the exhaust of treatment containing particulates in high amount effectively. Elimination of lower pressure drips (0.25 in w.g. etc. 10-15 in. w.g.) and broken or blind bag screening makes this design preferable to fabric collector. Wider tube space also provides continuous and interval wet operation of the wet electrostatic precipitator (3.5). Interval or continuous wet operation provides cleaning while operating. Therefore, an extra time is not needed or flushing. If desired, the cells can be cleaned by compressed air or slightly tapping or shaking instead of water or treatment solvent. Tubular design provides higher surface speed. For equal effectiveness, tubular precipitator can operate with higher volume of exhaust and thus a more compact design is provided. This characteristic will become more important if continuous operation of wet electrostatic precipitator (3.5) is allowed. The problems encountered due to new loading depending on high resistant or high conductive materials will be lost by wet operation of the wet electrostatic precipitator (3.5). It will be moved away as soon as the particulate is adhered. Because of its "sensitivity to wet" the wet electrostatic precipitator (3.5) can be made conformant to today's problems in scrubbers in down stream from wet scrubber. Depending on high effectiveness of the wet electrostatic precipitator (3.5) pressure decrease can be decreased in respect to current high power scrubber (such as Venturi). This will be a considerable power saving while increasing the system performance. Wet electrostatic precipitator (3.5) specially designed under the scope of the invention can be controlled by systemized and electronic equipment PLC and made of special stainless steel material.

Gas Extraction Fan (3.6): Solid fuel gasification and gas cleaning system developed under the scope of the invention operate under atmospheric pressure. Thus, gas safety of the system has been ensured. Since the system fully operates under atmospheric pressure, required gas extraction volume, pressure decrease is provided by a gas extraction fan (3.6). The sucking line of the gas extraction fan (3.6) provides pressure under atmospheric pressure to solid fuel feeding unit (1), solid fuel gasifier (2), ash extraction system (2.15), dust separator cyclones (3.1),wet gas cleaner (3.2) oil gas cleaner (3.3) and wet electrostatic precipitator (3.5).

Pumping line of the gas extraction fan (3.6) provides accumulation of gas in a gas storing tank (3.7) passage of it under pressure through gas conditioner (3.8) and gas cooling /heating part (3.9) line and supply of it into gas engine or gas turbine line where it is burned. Automation system is needed for passage of gas through suction line and gas pumping line under atmospheric pressure in a control manner. Therefore, gas explosion risk is not likely. Gas extraction fan (3.6) operating under atmospheric pressure in the system can be two-phased fan providing 400 mbar vacuum operating with centrifuge method.

Gas Storing Tank (3.7):

Gas storing tank (3.7) is of 150 m³ volume and is a floating storing tank operating while lower part is under water. It provides supply of produced cleaned gas into gas burning line without floatation in gas supply and supply required gas amount during stops.

Gas Conditioner (3.8):

The synthetic gas produced at solid fuel gasifier (2) and cleaned at gas cleaning unit (3) is stored in the gas storing tank (3.7) for a while before supplying it to gas engine, and flows into gas conditioner (3.8). The gas conditioner (3.8) filters the finally remaining dust particulates in the gas and provides required moisture for the gas. In addition, it adjusts gas pressure, gas engine pressure where power is produced. Gas leaving the gas conditioner (3.8) is supplied to the next part, gas cooling/heating zone (3.9) for required temperature adjustment and moisture adjustments.

Gas Cooling / Heating zone (3.9): The gas should be supplied to gas engine for burning in gas engine or gas turbine at a certain temperature, moisture, pressure and chemical quality. For this purpose, the gas is firstly cooled to temperature of +4 ⁰C to adjust the gas temperature at particularly final point and to condense the excess moisture, and the moisture is condensed according to dew point and excess moisture is removed so as to prevent change of operating conditions of gas engine by unnecessary moisture.

Cooling is conducted by means of heat exchanger in the gas cooling / heating part (3.9) and cold water or cold atmosphere is provided by ambient coolers. The gas leaving the water cooling system of air circulation passes through a heating system up to 40⁰C finally, and it is sent to gas engine or gas turbine at this temperature and appropriate pressure without moisture. If required, the moisture of the gas is kept under relative humidity of 60%.

Operating Capacity of Solid Waste Gasification and Gas Cleaning System:

It is likely to supply solid fuel of about 1 tons (± 0,25ton ) per hour to solid fuel gasification and gas cleaning system developed under the scope of this invention and produce 1500-1800 m³synthetic gas per hour. Gasification and gas cleaning system has been designed as modular system. If it is desired to increase the system capacity, new modules should be added. Each module will produce gas at capacity to produce 1 MWVeI power in average; that is the gas amount is of 1500- 1800 Nm3/hour.

It is likely to generate 1 MW electric and heat power at a certain times thereof by use of the synthetic gas obtained from each solid fuel gasifier (2). The crude synthetic gas produced at the solid fuel gasifier (2) contains low rate of tar. Carcinogenic agents such as dioxin and furan do not occur. Gasification zone of the solid fuel gasifier (2) should be operated at 1000-1200⁰C. The input and output values of stoichiometric simple mass balance in solid fuel gasification by solid waste gasifier (2) are as follows:

Raw material input value of solid fuel qasifier (2): solid fuel, 80 -110 mm diameter and 100-150 mm long briquette, pellet etc.; 1 ton/hour, min. 3500 mcal/kg. Output synthetic gas value of solid fuel qasifier (2) and gas cleaning unit (3): 1500-1600 kcal/Nm³, average 1800 Nm³/hour.

Physical characteristics of produced synthetic gas:

Gas pressure: 80-110 mBar (normally 100 mBar)

Gas temperature: 30-60 ⁰C (ideal 35⁰C) Gas density: 1.027 kg/m3 (40 ⁰C)

Specific thermal capacity (Cp): 1.25 kJ/kgK = 0.298 cal/grK

Chemical characteristics of produced synthetic gas:

Measuring method: Gas chromatography (TDC, two columns)

Main components: In volume-%: Methane CH₄: 2.0-3.0%

Ethan C₂H₆: ~0,5%

Propane C₃H₈: -0,3%

Butane C₄Hi₀:

Pentane C₅Hi₂: Hexane C6H14:

Carbon monoxide CO: 17-21 %

Hydrogen H₂: 9-12%

Carbon dioxide CO₂ 8-12%

Nitrogen N₂: 55-58% Oxygen O₂: 1 ,0%

Others: Track elements: ppm or mg/mN³:

Measuring system: EPA Standard; tar and dust measuring method Ammoniac NH₃: Total chloride: Total florid:

Hydrogen sulphur H₂S: Total silicate : Total sulfur: dust: 5 -10 mg/Nm³ Others: (tar and oil) 100 mg/Nm³

Automation should be considered while conducting gasification with the said solid fuel gasifier (2). The system operates fully with automation. All equipment in the system should be used according to the order. Otherwise, problems may occur during burning the gas in gas engines since adequate cleaning of gas cannot be provided.

The scope of protection of this invention has been specified under the claims part and cannot be limited to those described above for indicative purposes. It is obvious that any person skilled in the related art can suggest similar inventions by use of the embodiment described under this invention, by use of similar embodiments and/or can apply this embodiment to other fields of similar purposes. Therefore, it is obvious that such embodiments will lack invention and particularly excess of the criteria of the related art.

REFERENCE LIST

[1]-Tchobanoglous,G., Theisen.H., Vigil, S. (1993), 'Integrated Solid Waste Management¹, McGraw-Hill, New York, sf. 684-697.

[2]-Higman, C₁ Burght, M., 'Gasification', GPP, Elsevier, New York, 2003. [3]- http://www.qasification.org/. downloading date: May, 2007 [4]- http://www.qasification.de/. downloading date: 2007 [51-http://bαq.mek.dtu.dk/qasification/ downloading date: November, 2006

[6]-Tolay, M., "Clean Energy and Chemical Substance Production by Coal Gasification', ICCI 2007; 13. International Energy, Co-Generation and Environmental Technology Conference, 30-31 May 2007, Istanbul. [7]-Tolay, M., "Coal Gasification Systems and Design Methods', Energy World Magazine, publication 51 , May 2007, istanbul.(in Turkish)

[8]-Tolay, M., "Solid Waste Treatment and Compost Production', Recycling Magazine , published 1 , May 2007, Istanbul.

[9]-Califomia Energy Commission, 'Municipal Solid Waste Power Plants', http://www.energy.ca.gov/ downloading date: November, 2006

[10]-Mark A. Paisley, Robert D. Litt, and Kurt S. Creamer, 'Gasification Of Refuse- Derived Fuel In a High Throughput Gasification System', Energy From Biomass And Wastes XIV Lake Buena Vista, Florida January 29 - February 2, 1990

[11]-Eden R., 'Gasification of Domestic Waste for Energy Recovery and Waste Minimization', University of Warwick, the UK, 2002

[12]-U.S. Department Of Energy, 2004 National Energy Technology Laboratory, 'Gasifier Technologies', 2004.

[13]-Recovered Energy Inc., "Plasma Gasification Process Description Overview" http://www.recoveredenerqy.com. downloading date: May, 2007 [14]-M. Morris, L. Waldheim, 'Energy recovery from solid waste fuels using advanced gasification technology', Waste Management , volume: 18. publication 6- 8 , October 1998, page. 557-564.

[15]-V. Belgiorno, G. De Feo, 'Energy from gasification of solid wastes', Waste Management . volume: 23. publication 1. 2003, page 1-15 [16]-Klein, A., "An Alternative Process for Energy Recovery and Disposal Municipal Solid Wastes", M.S. Thesis, Columbia University, 2002.

[17]-Alameda Power and Telecom, "Investigation into Municipal Solid Waste Gasification for Power Generation", Draft to the Public Utilities Board, California, 2004. [18]-Wetherold, B., 'A Comparision of Gasification and Incineration of Hazardous Wastes', Final Report, DCN 99.803931.02, American power department, West Virginia, 2000.

[19]-Barducci, G., Uluvieri, P., Pike, D.C., McDonald, N., Repetto, F. And Cristo.F., 'The Greve in Chinati Project', Renewable Energy, 16, 1041-1044, 1999.

[20]-Chioni, M., La Marca, C, and Riccardi, J., 'RDF Gasification in a Circulated Bed Gasifier: Characterization of Syngas and Ashes', Gasification: the Clean Choice for Carbon Management, Noordwijk, The Netherlands, 08-10 Nisan, 2002.

[21]-Blue Ridge Environmental Defense League, 'Pyrolysis and Thermal Gasification of Municipal Solid Waste', Northern Carolina, 2002.

[22]-Michael, M., Pickett, R., 'Modeling The Performance And Emissions Of British Gas/Lurgi Based Integrated Gasification Combined Cycle Systems', M.S. Thesis, Northern Carolina State University, 2000.

[23]-Tolay, M., "Gasification of Solid Waste', Recycling Magazine , publication 2, June 2007, Istanbul.

[24]-http://www.detesenergy.com, / downloading date: Mayis, 2007

[25]-Tolay, M., Onal, N. S., Mancuhan, C₁ Salman, O., 'Solid Waste Gasification', Patent: International Application Number.:PCT/TR2005/000053, publication no.: WO/2007/037768, 2007. [26]-Yamankaradeniz, H., 'System of Production of Original Industrial Raw Materials by Gasification of Solid and Liquid Waste. in Closed Circuits', Patent International Application Number.:PCT/TR2006/01436, 2006

[27]-Dogru, M., Akay, G., 'Gasification', Patent: publication no: US 2006/0265954 A1. 2006 [28]-http://www.adamequipment.com/docs/fax/AMB.pdf, / downloading date: May, 2007

[29]-http://www.beltranassociates.com, / downloading date: May, 2007

[30]-CEN/BT/TF 143, 'Biomass Gasification - Tar and Particles in Product Gases -Sampling and Analysis', TC BT/TF 143 WICSC 03002.4, 10, 2004. [31]-Milne T.A., Abatzoglou N., Evans R.J, Biomass Gasifier "Tars": Their Nature, Formation and Conversion, National Renewable Energy Laboratory, Colorado, 1999

[32]-http://www.tarweb.net/images/train-1.gif, / downloading date: May, 2007 [33]-EPA-4, 'Determination of Moisture Content in Stack Gases', 2/2000. http://www.epa.gov/ttn/emc/promqate/m-04.pdf. / downloading date: May, 2007

[34]-EPA-5, 'Determination of Particulate Emissions from Stationary Sources', http://www.epa.gov/ttn/emc/promqate/m-05.pdf.. / downloading date: May, 2007

[35]-http://www.epa.gov/ttn/emc/promgate.html, / downloading date: May, 2007 [36]-Das, A, 'Contaminant Testing Method for Gasifier Engine Systems', The Biomass Foundation Press, Colorado, 1999.

[37]-Craig, J. G., 'Final Report and Gas Analysis for a Biomass Gasifier', Western Regional Energy Program, Texas, 2001.

[38]-Tolay, M., "Determination of Segregation and Agglomeration Tendencies in Fluidised Bed Using Temperature Measurements, PhD Thesisi, ITU, 1994, Istanbul.

[39]-Davies,I.L, Raynor.M.W., Urwin.D.J., Bartle.K.D., Tolay.M., Ekinci.E., Schwartz, H. I., "Analysis of Turkish Lignite Tar by Coupled LC/GC, GC/MS and Capillary SFC", Journal of High Resolution Chromatography and Chromatography Communications, Volume 11 , No 11 , page792-799, 1988.

[40]-Tolay,M., Ekinci.E., Davies.l., Raynor.M.W., Bartle.K.D., Scmalles.D.V., "Analysis of Turkish Gόynϋk Lignite Pyrolysis Products by Coupled HPLC/GC and Capillary SFC", 9th International Symposium on Capillary Chromatography, Conference Center, Monterey, California, May. 1988.

Claims

1. A system for gasification of solid fuels such as coal, lignite, petro coke, dangerous solid wastes, domestic solid waste, industrial solid waste, biomass covering wood charcoal, wood wool, wood shaving, agricultural wastes, treatment sludge, leather wastes, leather industry treatment sludge and cleaning of the produced gas characterized in that it comprises;

- a solid fuel feeding unit (1) feeding briquette or pellet solid fuels into the system

- a solid fuel gasifier (2) comprises a drying zone (2.1) providing vaporization of the water content of the solid fuel pellet or briquette, a pyrolysis zone

(2.2) located on the lower part of the said drying zone (2.1), wherein solid fuels are subjected to thermal deformation at temperature range of 400⁰C- 600⁰C and decomposed into coke, char, tar, CO, CH₄, and H₂, an oxidization zone (2.3) and a reduction zone (2.4) located on lower part of the said pyrolysis zone (2.2), wherein oxidization and reduction reactions are realized at temperature range of 1000°C-1200⁰C with heated air and organic compounds and char compounds having all high molecule weight of the pyrolyzed solid waste are oxidized and reduced and decomposed into CO, H₂, CO₂, CH₄ and light hydrocarbon of very light molecule weight, a strait zone (2.5) located on the lower part of the said reduction zone (2.4) where the obtained solid fuel gas and ash are conveyed, a screen zone (2.13) located on lower part of the said strait zone (2.5), a second oxidization zone (2.14) where the said screen part (2.13) combines with partial air once more and the remaining char is oxidized, - an ash extraction system (2.15) located on the lower part of the said solid fuel gasifier (2), an extraction and mixing apparatus (2.16) preventing agglomeration and sintering that might occur in the ash during gasification and wet discharge system (2.7) into which the produced ash is discharged.

- Gas cleaning unit (3) consisting of dust separator cyclones (3.1) providing cleaning of impurities such as dust, soot, ash grains, tar derivatives, H₂S,

HCN, dioxan, furan and water, and trapping dust particulates existing in raw gas leaving the solid fuel gasifier (2), wet gas flusher (3.2) where heavy char in raw basis in the gas, soluble char and chemical agents such as H₂S, HCN are passed through flushing solution and cleaned, wet solvent pool (3.2.1) located on the lower part of the wet gas flusher (3.2), wherein collected char and dust particulates are accumulated in form of soil upon agglomeration, oily gas flusher (3.3) wherein light char derivatives, char derivatives in form of aromatic and aliphatic structure not soluble in water, BTX aromatic compounds are passed through grease in order to be cleaned, flushing oil tank (3.3.1) located on lower part of the said oil gas flusher (3.3) wherein the accumulated tar are accumulated, sand filters (3.4) used to recycle water solvents and oil solvents used in wet gas flusher (3.2) and oil gas flusher (3.3), wet electrostatic precipitator (3.5) wherein liquids, dust particulates, heavy metal particulates, acid fogs, smokes, dioxan or furan compounds of aerosol in micron size are electric loaded and providing holding in the water saturated gas, a gas emission fan (3.6) providing gas emission from the system and pressure decrease, gas storing tank (3.7) providing supply of produced cleaned gas into gas burning line without floating in gas supply and procuring the required gas amount in case of various stops, gas conditioner (3.8) which filters the dust particulates remaining in synthetic gas produced and cleaned in solid fuel gasifier and provides required moisture to the gas, gas cooling / heating part (3.9) where the temperature adjustments and moisture adjustments of the gas from gas conditioner (3.8) are provided.

2. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that the said solid fuel pellets or briquettes are of 80 - 110 mm diameter and 100 -150 mm long.

3. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that the moisture content rate of the said solid fuel pellets or briquettes is 10 - 15% in weight.

4. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that the said solid fuel gasifier (2) comprises an inner zone (2.6) entirely or partially coated with refractory material depending on type of the solid fuel.

5. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that the said solid fuel feeding unit (1) comprises a valve air locking system (1.1), solid fuel silo (1.2) and weighing system (1.3).

6. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises a level control system (2.17) located on the said solid fuel gasifier (2).

7. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises a vibrator (2.10) located on the said solid fuel gasifier (2) and providing vibration.

8. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one air preheating chamber (2.11) located on lower part of the said solid fuel gasifier (2), heating the coming air and taking its heat from wall of the solid fuel gasifier (2).

9. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one air incoming chamber (2.18) connected to the said second oxidization zone (2.14) and supplying the heated air.

10. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one nozzle

(2.12) providing supply of the air to solid fuel gasifier (2).

11. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one air inlet duct (2.8) located on the strait zone (2.5) and supplying the heated air.

12. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one control valve (2.9) providing control of air inlet.

13.A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises one pre-dust separator (2.19) located around the said solid fuel gasifier (2).

14. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises at least one gas output pipe (2.20) located on the said pre-dust separator (2.19).

15. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that it comprises rotary valve (3.1.1) located on the lower part of the said separator cyclones (3.1) and removing the dusts from the separator cyclones (3.1) and supplying it into ash extraction system (2.15), and air locking system (3.1.2).

16. A system for gasification of solid fuels and cleaning of the produced gas according to claim 1 characterized in that the said wet electrostatic precipitator

(3.5) comprises one gas inlet part (3.5.1), one gas flushing and moistening zone (3.5.2), one filter (3.5.3) one electrostatic precipitator (3.5.4) and gas output (3.5.5).