biomass gasifier
  • Technology of Biomass Gasification

    What is biomass gasification?

     

    Biomass gasification is a thermo chemical technology, by the action of partial air (oxygen) and water vapor, biomass raw material will produce combustible gases through pyrolysis, oxidation and reduction reactions. The combustible gas can be used for centralized gas supply, heating, and power generation, etc.

     

    Gasification is the key conversion technology in all processes for the production of energy, fuels or products from biomass. In electricity production biomass is thermally converted by gasification into a combustible gas that can be used in a gas engine or turbine with electricity as well as heat as products. The advantage of the gasification route is the higher overall electric efficiency compared to the alternative of direct biomass combustion. In the process of fuels and chemicals the combustible gasification gas is used in a catalytic process to synthesis the desired product.

    Biomass Gasifier

    The gasifier is actually a chemical reactor where biomass fuel is converted to gas, there are four processes take place in the gasifier:

     

    Drying: In drying process, the moisture of biomass comes out in the form of water vapor. Typically the resulting water vapor is mixed into the gas flow and be involved with subsequent chemical reactions.

     

    Pyrolysis: The pyrolysis process take place at temperature of above 200 degree C. During pyrolysis, the organic material of biomass is decomposed, volatiles and char are produced.

     

    Combustion: Volatile products and some char react with oxygen to primarily form carbon dioxide and small amounts of carbon monoxide, heat and energy are released.

     

    Reduction: The char reacts with H2O and carbon dioxide to produce carbon monoxide and hydrogen.

    The gasifier is actually a chemical reactor where biomass fuel is converted to gas, there are four processes take place in the gasifier:

     

    Drying: In drying process, the moisture of biomass comes out in the form of water vapor. Typically the resulting water vapor is mixed into the gas flow and be involved with subsequent chemical reactions.

     

    Pyrolysis: The pyrolysis process take place at temperature of above 200 degree C. During pyrolysis, the organic material of biomass is decomposed, volatiles and char are produced.

     

    Combustion: Volatile products and some char react with oxygen to primarily form carbon dioxide and small amounts of carbon monoxide, heat and energy are released.

     

    Reduction: The char reacts with H2O and carbon dioxide to produce carbon monoxide and hydrogen.

    Biomass Gasification:    Carbonaceous Material +Controlled Oxygen+Heat →Gases + Tars + Char

  • Biomass Fuel

    Biomass refers to the organic carbon-containing materials produced through photosynthesis by the use of air, water, land. Biomass is available in many forms, comprising products as well as residues from agriculture, forestry and agro-industry.

    It is characterized by renewability, less pollution, wide distribution and abundant resources. During growth of the plants, crops, and trees, co2 is withdrawn from the atmosphere and stored in the biomass as chemical energy. The co2 cycle is closed again when co2 is released during conversion of the biomass and the derived products. The renewble and co2-neutral nature of biomass is the major motivation to use the material for the energy generation.

    Biomass Ash-Biochar

    By gasification of biomass raw material, the ash produced is called as “ biochar”. Biochar can be used as a soil conditioner to improve soil conditions and environment.   Biochcar has advantages of porous, large specific surface area and adundant functional groups, when it is added to the soil, it can improve the water-holding capacity of soil and the structure of the soil porosity, reduce soil bulk density and so on. In addition, biochar is alkaline, it can neutralize the soil acidity, and thus to improve PH value of the soil.

    The more pore sturcture and stronger absorption capacity of biochar make it have stronger element absorption capacity it the soil. Some properties of biochar can also affect the stability of elements and the activity of soil microorganisims, so as to promote the cation of exchange of soil and improve and maintain the fertility of soil.

    Biochar not only have a great effect on soil improvement, but also have a great effect on growth and quality improvement of crop.

  • Biomass Gasifier Type

    Manufacturer of Biomass Gasifier

    Carrysun Technology is a biomass gasifier manufacturer that make gasifier with high quality and efficiency. The gasifier is a thermo-chemical reactor in which the biomass (i.e. wood chips, husk, ) is gasified to syngas through pyrolysis, combustion, and reduction.

    Comparation Between Four Types of Gasifier 

    The rotary type gasifier is basically an improved updraft fixed bed gasifier.

     

  • Biomass Power Plant

    Main Equipment:

    1. Feeding Elevator          2. Gasifier          3. Cyclone Dust Collector          4. Heat Exchanger          5. ESP(Dry Type)       

    6. Gas Tank         7. Gas Flare       8. Gas Generator Sets

    Flow Chart of Biomass Power Plant

    Technical Parameters of Biomass Gasification Power Generation System

     

  • Gas Generator Set

    Biomass gas generator sets uses biomass pyrolysis gas as fuel. Biomass gas is combustible gas obtained by pyrolysis gasification of various biomass feedstock, such as straw, wood chips/waste, branches, shells, husks and municiple wasste, etc.. The main combustible gas compositions are CO, H2 and CH4. Normally the biomass gas produced contains lots of tar, water and ash, which is not good for operation of gas engine, so the gas must be cleaned before entering engine. Using biomass waste as raw fuel to produced fuel gas is a good substitue of fossil fuel and also can reduce emissions to environment, The development and utilization of biomass energy by modern technology has great significance to the establishment of sustainable energy system, the promotion of social and economic development and the improvement of ecological environment.

     

    Quality requirements for biomass gas: within 1 meter to gas inlet valve of gas engine:

    1. Temperature of gas ≤40℃;
    2. Gas pressure : 1.5-15kpa, pressure change ratio≤1kpa/min;
    3. H2S ≤20mg/Nm³;
    4. NH3≤20mg/Nm³;
    5. Tar Content ≤20mg/Nm³;
    6. Impurity granularity≤5um, Impurity content ≤30mg/Nm³;
    7. Moisture content of gas ≤20mg/Nm³;
    8. CalorifiC Value of Gas ≥4.2MJ/Nm³

    Technical Parameters of Biomass Gas Generator Set

    Pictures: Biomass Gas Generator Sets

  • Gas Conditioning System

    ESP(electrostatic precipitator) is a gas initial cooling equipment which uses high voltage direct current electric to separate the tar and the gas. It has characteristics of high efficiency (can reach 99%), small resistance loss and large handling capacity, etc.

    There are three types of ESP structure: concentric circle, tube and honeycomb. The woring principle is, high voltage direct current is applied to maintain an electric fieldsufficient to ionize the gas, creating a corona area between the anode and the cathode.

    The positive ions are absorbed on the negatively charged corona pole, and the negative ions are absorbed on the positively charged precipitation pole. All ionized positive and negative ions fill in the entire space between the corona pole and the precipitate pole. When the gas containing tar droplets and other impurities passes through the electric field, the impurities absorbing negative ions and electrons move to the precipitate pole under the action of coulomb force, and release the charge and absorb on the precipitate pole. So as to achieve the purpose of purifying gas, which is usually called the charge phenomenon. When the impurity mass absorbed on the precipitate electrode increases to more than its adhesion, it will automatically flow down and discharge from the bottom of the electric tar trap, while the net gas will leave from the upper part of the electric tar trap and enter the next process.

    The syngas produced by gasifier comntains lots of impurities (i.e. tar, particles,etc.). Before sending the syngas to gas generator sets, it will need to purify the syngas through gas conditioning system. The main equipment is ESP(Electrostastic Precipitator), which can effectively remove the tar and particles from the produced syngas.

    Electrostastic Precipitator (ESP)