JP5557041B2 - Pretreatment apparatus and pretreatment method for herbaceous biomass - Google Patents

Description

  The present invention relates to a pretreatment apparatus and a pretreatment method for performing pretreatment before using herbaceous biomass as fuel, gasification raw material, or carbide raw material.

  Attention has been focused on the effective use of biomass energy as a measure to prevent global warming. Biomass is a renewable, organic resource that is not a fossil resource. In particular, among biomass, plant-derived biomass can effectively use carbon resources converted from carbon dioxide by photosynthesis during the plant growth process, and therefore does not lead to an increase in atmospheric carbon dioxide from the viewpoint of the life cycle of the resources. Since biomass is an organic substance, carbon dioxide is emitted when it is burned. However, the carbon contained in this is derived from carbon dioxide absorbed from the atmosphere by photosynthesis during the growth process, so using biomass does not increase the amount of carbon dioxide in the atmosphere as a whole It can be considered that. This property is called carbon neutral. Of plant-derived biomass, herbaceous biomass, particularly oil palm empty fruit bunches and kinggrass described below, are expected to reduce carbon dioxide emissions.

  Studies have been made to effectively use the remaining empty fruit bunches when extracting palm oil from oil palm fruit. There are hundreds of small fruits with a diameter of several centimeters in the oil palm fruit bunch, and the fruit that is removed from the fruit is called the empty fruit bunch (EFB). Since the fruit is strongly bound to the core of the fruit bunches, in order to weaken this bond and facilitate separation, and to suppress alteration of the oil extraction components, the fruit bunches are heated with steam, and then the fruit is removed by a rotary sieve or the like. End. A large amount of empty fruit bunches with high water content were discharged, but they were discarded without being used effectively or left outdoors. Kinggrass is an energy crop that grows significantly faster, and the use of stems as fuel is being studied.

In recent years, attention has been paid to using biomass as an energy source to reduce CO ₂ gas emissions, and attempts have been made to effectively use oil palm empty fruit bunch as boiler fuel. Patent Document 1 proposes an apparatus used for this purpose. The apparatus of Patent Document 1 includes a steam-heated fruit removing machine that separates fruits and empty fruit bunches with a rotary sieve under steam pressure, an empty fruit bun cutting machine that cuts the empty fruit bunches after ripening, and an empty fruit after cutting. It is equipped with an empty fruit bunch press that squeezes the bunch. The empty fruit bunch is cut into fiber strips by an empty fruit bunch cutting machine, and then the water is removed by the empty fruit bunch press and used as boiler fuel.

JP-A-3-146593

  However, herbaceous biomass such as oil palm empty fruit bunch or kinggrass is burned in a combustion furnace as boiler fuel and the combustion heat energy is recovered, or gasified as gasification raw material in a gasification furnace to obtain fuel gas or chemical raw material gas In some cases, the herbaceous biomass contains an alkali metal such as potassium (potassium content of about 3% by weight (dry base)), and the ash content of the residue obtained by burning or gasifying the herbaceous biomass contains a lot of potassium. Cause problems. In other words, if the ash contains a lot of potassium, the ash is fused to the inner wall of the combustion furnace or gasification furnace, resulting in slugging that hinders the flow of the gas in the furnace, and the operation of the combustion furnace or gasification furnace is unstable. Ash is fused to the waste heat recovery boiler, fouling occurs and the flow of exhaust gas is hindered, heat transfer efficiency of the heat transfer tubes etc. is reduced, and heat recovery is hindered, and in the fluidized bed furnace, silica sand, etc. As a result, molten ash adheres to the surface of the fluidized particles and the fluidized particles are agglomerated, causing problems in the operation of the furnace.

  In addition, if potassium is contained in the carbide produced from the herbaceous biomass as a carbide raw material, the same problems occur when the carbide is used as a fuel. Also, the carbide of the herbaceous biomass is used as blast furnace blown pulverized coal (reduced blast furnace reduction). When used as a material, there is a problem in that potassium stays in the blast furnace, causing blockage or deterioration of air permeability in the furnace.

  In view of such circumstances, the present invention is a herbaceous biomass that can prevent the occurrence of problems caused by the inclusion of potassium in the herbaceous biomass when using the herbaceous biomass as a fuel, gasification raw material, or carbide raw material. It is an object of the present invention to provide a preprocessing apparatus and a preprocessing method.

  In order to solve the above-mentioned problems, the present inventors tried to remove potassium contained in herbaceous biomass by washing with water, but potassium was simply removed by washing with water or warm water and dehydrating. It has been found that the potassium content cannot be reduced to such an extent that no trouble occurs in the combustion furnace or the like. Furthermore, as a result of intensive studies, it has been found that the potassium content can be sufficiently reduced by providing the following configuration, leading to the present invention.

  According to the present invention, the above-described problems are solved by the following configuration for the herbaceous biomass pretreatment apparatus and pretreatment method.

<Pretreatment device>
The pretreatment apparatus for herbaceous biomass according to the present invention performs pretreatment before using the herbaceous biomass as fuel, gasification raw material, or carbide raw material.

  In such a pretreatment apparatus, the present invention is characterized in that a means for pressing and dehydrating herbaceous biomass, adding water thereafter, and pressing and dehydrating again has a pressing and dehydrating apparatus configured as one apparatus.

  The press dewatering device is a screw press dewatering device that accepts herbaceous biomass, presses and dehydrates, presses and dehydrates the squeezed dehydrated herbaceous biomass transferred from the first press dewatering unit, and squeezes dehydrated herbaceous biomass. It is preferable to have a second squeezing and dehydrating unit that squeezes and dehydrates the hydrous herbaceous biomass again and discharges the dehydrated herbaceous biomass.

  The pressure dewatering device is a filter press dewatering device, and has a filtration chamber that receives herbaceous biomass in the gap between the filter media facing each other, and a water supply section that hydrates the dehydrated herbaceous biomass in the filtration chamber, After the received herbaceous biomass is squeezed and dehydrated, it is added to the dehydrated herbaceous biomass from the hydration supply unit, and is squeezed and dehydrated again to discharge the dehydrated herbaceous biomass.

<Pretreatment method>
The pretreatment method for herbaceous biomass according to the present invention performs pretreatment before using the herbaceous biomass as fuel, gasification raw material or carbide raw material.

  In such a pretreatment method, in the present invention, the first press dehydration step of pressing and dehydrating the herbaceous biomass, the hydration step of adding water to the dehydrated herbaceous biomass squeezed and dehydrated in the first press dehydration step, and the hydration step And a second squeezing and dehydrating step for squeezing and dehydrating the hydrolyzed biomass again, and performing the above three steps with a single squeezing and dewatering device.

  In the present invention, a first press dehydration step for receiving and dehydrating herbaceous biomass in the upstream portion of the screw press dehydrator, and a hydration step for adding water to the dehydrated herbaceous biomass transferred from the upstream portion in the middle portion of the screw press dehydrator And a second squeezing and dehydrating step of squeezing and dehydrating the herbaceous biomass transferred from the midstream part in the downstream part of the screw press dehydrator.

  Further, in the present invention, the first press dehydration step of supplying herbaceous biomass to the filter chamber of the filter press dehydrator and compressing and dehydrating, the hydration step of adding water to the dehydrated herbaceous biomass in the filter chamber, and the hydration of the filter chamber It may be characterized by having a second squeezing and dehydrating step of squeezing and dehydrating the herbaceous biomass again.

  The pretreated herbaceous biomass pretreated by the herbaceous biomass pretreatment apparatus and pretreatment method of the present invention is supplied to a combustion furnace as fuel and burned, and heat is recovered from the combustion gas in a boiler to obtain steam, Power can be generated by a turbine generator or used as a heat source. As the combustion furnace, known biomass combustion furnaces such as a fixed bed furnace, a fluidized bed furnace, a circulating fluidized bed furnace, and a rotary kiln can be used, and the potassium in herbaceous biomass is greatly reduced by pretreatment. It can burn smoothly and recover heat.

  Further, the pretreated herbaceous biomass pretreated by the herbaceous biomass pretreatment apparatus and the pretreatment method of the present invention is supplied to a gasification furnace as a gasification raw material, gasified by partial combustion and pyrolysis, and gasified The fuel gas can be supplied to a gas engine generator for power generation, or the fuel gas can be burned with a combustion device to recover the combustion heat. Further, gas can be gasified to obtain a chemical raw material gas to synthesize methanol and the like. As the gas furnace, a known biomass gas furnace, for example, a fixed bed furnace or a fluidized bed furnace can be used, and potassium in the herbaceous biomass is greatly reduced by pretreatment, so that it can be smoothly gasified without any trouble. Can do.

  Furthermore, pre-treated herbaceous biomass can be supplied to a carbonization furnace as a carbide raw material and carbonized to obtain a carbide, and the carbide can be used as fuel or used as blast furnace blown pulverized coal (reducing material for blast furnace). May be. As the carbonization furnace, a known carbonization furnace, for example, a packed moving bed furnace or a rotary kiln can be used. Since potassium in the herbaceous biomass is greatly reduced by the pretreatment, the carbonization can be performed smoothly without any trouble.

  In the present invention configured as described above, the herbaceous biomass is treated in the following manner in the press dehydration apparatus and the pretreatment method in which the first press dehydration, the hydration and the second press dehydration are configured in one apparatus. Is done. Here, a case where the pressing dewatering device is a screw press dewatering device and a case where it is a filter press dewatering device will be described.

<Screw press dehydrator>
(1) In the first press dehydration unit and the first press dehydration step of the screw press dehydrator, the herbaceous biomass is dehydrated (first press dehydration). By pressing and dewatering, the water containing potassium eluted from the herbaceous biomass is removed, and by pressing and pressurizing, the water containing potassium is leached from the stalks and the like of the herbaceous biomass, and further, the herbaceous biomass It softens the core and other small pieces, breaks the cell membrane, and exudes intracellular potassium into the surrounding water.

  (2) In the hydration part and the hydration process, water is added to the herbaceous biomass depressurized and dehydrated in (1) above. By adding water to the squeezed and dehydrated herbaceous biomass, the pressure applied by the squeezing is released and the moisture is absorbed while expanding, so the herbaceous biomass is absorbed efficiently in a short time. At the same time, water spreads to the inside and the remaining potassium can be sufficiently eluted in the water.

  (3) In the second squeezing / dehydrating part and the second squeezing / dehydrating step, the herbaceous biomass hydrated in the above (2) is squeezed again (second squeezing / dehydrating). By squeezing and dehydrating the herbaceous biomass that has been hydrated and absorbing moisture, the potassium content in the herbaceous biomass can be further reduced on the same principle as the first squeeze dehydration.

  Thus, when the herbaceous biomass is burned in a combustion furnace as fuel, when it is gasified and carbonized, the potassium content is set to such an extent that it does not hinder the recovery of the combustion and combustion heat, gasification and carbonization. Reduced herbaceous biomass can be obtained.

<Filter press dehydrator>
(1) Herbaceous biomass is squeezed and dehydrated (first squeezing dehydration) in the filter chamber and the first squeezing dehydration step of the filter press dehydrator. By pressing and dewatering, the water containing potassium eluted from the herbaceous biomass is removed, and by pressing and pressurizing, the water containing potassium is leached from the stalks and the like of the herbaceous biomass, and further, the herbaceous biomass It softens the core and other small pieces, breaks the cell membrane, and exudes intracellular potassium into the surrounding water.

  (2) In the filtration chamber and the hydration step, water is added to the herbaceous biomass depressurized and dehydrated in (1) above. By adding water to the squeezed and dehydrated herbaceous biomass, the pressure applied by the squeezing is released and the moisture is absorbed while expanding, so the herbaceous biomass is absorbed efficiently in a short time. At the same time, water spreads to the inside and the remaining potassium can be sufficiently eluted in the water.

  (3) In the filtration chamber and the second squeezing dehydration step, the herbaceous biomass hydrolyzed in the above (2) is squeezed again (second squeezing dehydration). By squeezing and dehydrating the herbaceous biomass that has been hydrated and absorbing moisture, the potassium content in the herbaceous biomass can be further reduced on the same principle as the first squeeze dehydration.

  Thus, when the herbaceous biomass is burned in a combustion furnace as a fuel, when it is gasified, and when carbonized, the potassium content is such that the combustion and recovery of combustion heat, gasification and carbonization do not hinder. It becomes possible to obtain a herbaceous biomass having a reduced amount.

  The herbaceous biomass supplied to the filter chamber of the filter press dehydrator is subjected to the first press dehydration, hydration, and second press dehydration while remaining in the filter chamber, and the herbaceous biomass with reduced potassium content is obtained. Discharged.

  In the present invention, as described above, the first press dehydration is performed on the herbaceous biomass and then the water is added, and then the second press dehydration is performed, thereby effectively reducing the potassium content of the herbaceous biomass. . As a result, when using herbaceous biomass as fuel, gasification raw material and carbonization raw material, it is possible to prevent troubles in the operation of the combustion furnace such as slugging in the furnace and aggregation of fluidized particles. In addition, fouling in the waste heat recovery boiler can be prevented and trouble in heat recovery can be prevented, and the obtained carbide can be used without any problem.

  In addition, the present invention has a press dehydration device in which a unit for compressing and dehydrating herbaceous biomass, then adding water, and then pressing and dehydrating again is configured in one device, so that the potassium reduction treatment of herbaceous biomass is performed in one device. The equipment can be compact, the equipment cost can be reduced, and the operation can be performed easily.

It is a block diagram which shows the outline of a structure of the pre-processing apparatus which concerns on 1st embodiment of this invention. It is a figure which shows the structure of the screw press dehydration apparatus as a pressing dehydration apparatus which concerns on 1st embodiment, (A) shows sectional drawing in the surface containing the axis line of the screw shaft of a screw press dehydration apparatus, (B) Shows a cross-sectional view in a plane perpendicular to the axis. It is a longitudinal cross-sectional view which shows the structure and operation | movement of the pressing dehydration apparatus which concerns on 2nd embodiment of this invention, and has shown the biomass supply process. It is a longitudinal cross-sectional view which shows the structure and operation | movement of the pressing dehydration apparatus which concern on 2nd embodiment of this invention, and has shown the 1st pressing dehydration process and the 2nd pressing dehydration process. It is a longitudinal cross-sectional view which shows the structure and operation | movement of the pressing dehydration apparatus which concerns on 2nd embodiment of this invention, and has shown the hydration process. It is a longitudinal cross-sectional view which shows the structure and operation | movement of the pressing dehydration apparatus which concerns on 2nd embodiment of this invention, and has shown the biomass discharge process.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<First embodiment>
In the present invention, oil palm empty fruit bunch or kinggrass can be used as the herbaceous biomass. This embodiment demonstrates as what uses an oil palm empty fruit bunch as herbaceous biomass.

  FIG. 1 is a block diagram showing an outline of the configuration of the preprocessing apparatus according to the present embodiment. FIG. 2 is a diagram illustrating a configuration of a screw press dewatering device as a press dewatering device according to the present embodiment, and (A) is a cross-sectional view of a surface including an axis of a screw shaft of the screw press dewatering device, (B) shows a cross-sectional view in a plane perpendicular to the axis.

  As shown in FIG. 1, the pretreatment device according to the present embodiment prepares to supply the oil palm empty fruit bunches as herbaceous biomass to the squeezing and dewatering device 10, and crushing apparatus 3 for crushing the oil palm empty fruit bunches. And a dispersing device 4 for dispersing the crushed empty fruit bunches in water. Further, as an apparatus for taking out the empty palm fruit bunches from the oil palm fruit bunches, a steam heating apparatus 1 for heating the oil coconut fruit bunches with water vapor, and a fruit removing apparatus 2 for defruiting the fruits from the heated oil coconut fruit bunches into empty fruit bunches, Is provided.

  The oil palm fruit bunch has several hundred to about 2000 fruits having a size of about 3 to 4 cm on the stem portion that will later become an empty fruit bunch. The said steam heating apparatus 1 accommodates this oil palm fruit bunch in a cage, sprays water vapor | steam to this, and maintains the state heated with water vapor | steam for about several tens of minutes. By being heated with this steam, the fruit is easily separated from the stem portion.

  The fruit removal device 2 has a horizontal cylindrical rotary sieve. When the oil palm bunch is put into the rotary sieve from one end side, it receives impact force by rotation while reaching the outlet on the other end side. The fruit is separated from the stem portion and falls from the sieve mesh on the side of the rotary sieve, and the remaining empty fruit bunches are discharged from the outlet. This empty fruit bunch contains about 70% by weight of water and is brought to the crushing device 3.

  In this embodiment, since the oil palm empty fruit bunch was used as the herbaceous biomass, a steam heating device and a defruiting device were provided. However, when using, for example, kinggrass as the herbaceous biomass, the steam heating device and the dehulling device are provided. The fruit apparatus can be omitted.

  The crushing device 3 crushes the oil palm empty fruit bunch to a size suitable for pretreatment. Although this crushing apparatus 3 is not limited to the crushing format, for example, a biaxial crusher can be used. This biaxial crusher is provided with a number of cutter blades around the fuselage respectively supported by two parallel shafts rotating in reverse, and herbaceous biomass that has entered between the two fuselage is It is cut into a predetermined size and falls. When the oil palm empty fruit bunch is used as the herbaceous biomass as in this embodiment, the empty fruit bunch is cut into a size of, for example, less than 100 mm. The dispersion device 4 mixes and disperses the oil palm empty fruit bunches crushed by the crushing device 3 in the water accommodated in the container. The oil palm empty fruit bunches are brought to the squeezing and dehydrating apparatus 10. Note that the distribution device is not an essential configuration and can be omitted.

  The pressing and dehydrating apparatus 10 includes a first pressing and dehydrating unit 11, a hydrating unit 12, and a second pressing and dehydrating unit 13 in order. As seen in FIGS. 2A and 2B, the press dewatering device 10 is configured as a screw press dewatering device, and a horizontal cylindrical casing (not shown) has a horizontal cylindrical shape. A screen 14 is provided, and a screw shaft 15 extending coaxially with the screen is disposed in the screen 14. The squeezing and dehydrating apparatus 10 receives the crushed oil palm empty fruit bunch from the supply port 10A located on the upstream side (the left side in FIG. 2A), and preprocesses the oil palm empty fruit bunch on the downstream side ( It discharges | emits from the discharge port 10B located in the FIG. 2 (A) right side. The squeezing and dehydrating apparatus 10 is formed of three regions: a first squeezing and dehydrating part 11 located in the upstream part, a hydration part 12 located in the midstream part, and a second squeezing and dehydrating part 13 located in the downstream part.

  The screen 14 is made of, for example, a punching metal or a wedge wire screen, and is provided with an infinite number of pores (not shown) having a pore diameter of about several hundred μm to several mm. The screen 14 has three regions of a first dewatering screen 14A, a water dehydrating screen 14B, and a second dewatering screen 14C corresponding to the first press dehydrating unit 11, the water adding unit 12, and the second press dehydrating unit 13, respectively. ing.

  The screw shaft 15 is tapered so that the outer diameter gradually increases from the supply port 10A side toward the discharge port 10B side. That is, the radial interval between the screw shaft 15 and the screen 14 is gradually reduced from the supply port 10A side in the axial direction toward the discharge port 10B side. On the outer peripheral surface of the screw shaft 15, a spiral blade 15 </ b> A is provided that extends over almost the entire area in the axial direction (the left-right direction in FIG. 2A). The screw shaft 15 is rotationally driven around the axis by a screw driver 16 connected to the screw shaft 15, and the oil palm empty fruit bunch is transferred toward the discharge port 10B side by the rotation of the blade 15A. Yes.

  As shown in FIG. 2A, on the outside of the hydration screen 14B in the hydration section 12, a plurality of nozzles 18 for injecting water supplied from the hydration pipe 17 toward the hydration screen 14B are screw shafts 15. Are provided in the axial direction. Further, as seen in FIG. 2B, a plurality of nozzles 18 are arranged in the circumferential direction. The nozzle 18 is preferably swingable in the circumferential direction. Water sprayed from the nozzle 18 toward the hydration screen 14B is supplied to the oil palm empty fruit bunch through the pores of the hydration screen.

  Hereinafter, the pretreatment of the oil palm empty fruit bunches by the pressing and dehydrating apparatus 10 will be described.

  The oil palm empty fruit bunch crushed by the crushing device 3 and dispersed by the dispersing device 4 is supplied to the radial interval between the screw shaft 15 and the screen 14 in the first squeezing / dehydrating part 11 of the squeezing / dehydrating device 10. Then, the screw shaft 15 is rotated to the discharge port 10B side. Since the said space | interval becomes narrow as it goes to the discharge port 10B side, an oil palm empty fruit bunch is squeezed by the screw shaft 15 and the screen 14, and a water | moisture content is discharged | emitted from the 1st dehydration screen 14A. During the squeezing, water squeezed from the empty palm fruit bunch (referred to as squeezed water) is filtered by the first dewatering screen 14A and drained out of the casing. Since this compressed water contains potassium, the elution of potassium from the oil palm empty fruit bunch is eliminated by discharging the compressed water.

  In the hydration part 12, the oil palm empty fruit bunch (dehydrated herbaceous biomass) squeezed and dehydrated in the first squeezing and dehydrating part 11 is hydrated by sprinkling water from the nozzle 18 toward the hydration screen 14B. By adding water to the pressed and dehydrated oil palm empty fruit bunches, the oil empty fruit bunches are absorbed with moisture and spread to the inside, and the remaining potassium can be sufficiently eluted into the water.

  In the second squeezing and dehydrating part 13, the oil palm empty fruit bunches (hydrous herbaceous biomass) squeezed by the hydrating part 12 are squeezed again in the same manner as the first squeezing and dehydrating part 11, and the squeezed water is supplied from the second dehydrating screen 14C. Discharged. The compressed water is filtered by the second dewatering screen 14C and drained out of the casing. Since the compressed water contains potassium, the elution of potassium from the oil palm empty fruit bunch is eliminated by discharging the compressed water. The compressed and dehydrated oil palm empty fruit bunch (dehydrated herbaceous biomass) is discharged from the discharge port 10B side in the second squeezed and dehydrated portion 13 in a state where potassium elution is eliminated.

  The water obtained by oil-water separation of the compressed water squeezed from the first press dehydration unit 11 and the second press dehydration unit 13 is useful as a fertilizer because it contains potassium in a high concentration. As it is, it can be used as fertilizer after spraying or concentrating on the farm. The reason why the compressed water squeezed out from the second squeezing and dewatering part 13 also contains high-concentration potassium is that the amount of water hydrated in the hydration part 12 is dehydrated in order to elute potassium, This is because the amount of potassium contained in the squeezed solution is relatively high because the amount is sufficient. For this reason, the value as the fertilizer of the water | moisture content which carried out the oil-water separation of the press-dewatered compressed water is high.

  In such a pretreatment device according to the present embodiment, the herbaceous biomass is crushed to a predetermined size by the crushing device 3 and squeezed and dehydrated by the first squeezing and dehydrating unit 11 so that the water content is greatly reduced. Biomass. The dehydrated herbaceous biomass is hydrated by the hydration unit 12 and absorbs moisture appropriately, and is squeezed and dehydrated again by the second squeezing and dehydration unit 13, and the moisture is greatly reduced.

  The crushed herbaceous biomass is squeezed and dehydrated by the first squeezing and dehydrating unit 11 to remove moisture containing potassium eluted from the herbaceous biomass, and squeezed and pressurized to remove small pieces such as stems of herbaceous biomass. In addition, water containing potassium can be leached, and further, a flake such as a core of herbaceous biomass can be softened, the cell membrane can be broken, and intracellular potassium can be leached into the surrounding water. By adding water to the dehydrated herbaceous biomass that has been squeezed and dehydrated by the hydration unit 12, the moisture is absorbed and the moisture is spread to the inside, and the remaining potassium can be sufficiently eluted into the moisture. Further reducing the potassium content in the herbaceous biomass by the same principle as the first squeezing and dehydrating unit 11 by squeezing and dehydrating the hydrolyzed herbaceous biomass that has been hydrated and absorbed moisture in the second squeezing and dehydrating unit 13. Can do.

  Further, in this embodiment, since the means for squeezing and dehydrating herbaceous biomass, the means for adding water thereafter, and the means for squeezing and dehydrating again have a compression dehydrator configured in one screw press dehydrator, potassium of herbaceous biomass Reduction processing can be performed by a single device, equipment is compact, equipment costs can be reduced, and driving operations can be performed easily.

  In the present embodiment, two squeezing / dehydrating units and one hydration unit are provided, but the number of squeezing / dehydrating units and hydration units provided in one squeezing / dehydrating device may be increased as necessary. In this case, the pressing dewatering unit and the water adding unit are provided alternately.

<Combustion and heat recovery>
The pretreated dehydrated herbaceous biomass taken out from the press dehydrator 10 is supplied to a combustion furnace as fuel and burned, and heat is recovered from the combustion gas in a boiler to obtain steam, which can be generated by a steam turbine generator. Can be used as a heat source. As the combustion furnace, known biomass combustion furnaces such as a fixed bed furnace, a fluidized bed furnace, a circulating fluidized bed furnace, and a rotary kiln can be used. As a heat recovery apparatus for recovering heat of combustion generated by burning compressed biomass in a combustion furnace, a boiler that generates steam, a heat exchanger that exchanges heat to obtain hot water or heated air, and the like are used. Electric power can also be obtained by connecting a generator that drives the steam turbine using the generated steam to generate electricity.

  In addition, since the pretreated dehydrated herbaceous biomass has a significantly reduced potassium content, it can prevent the occurrence of problems caused by the inclusion of potassium when burned in a combustion furnace as fuel. And can be burned smoothly and stably without hindrance, and the heat of combustion can be efficiently recovered. Moreover, the water | moisture content obtained by carrying out oil-water separation of the pressing water squeezed out from a pressing dehydration part contains potassium, and is used as a fertilizer as mentioned above.

  In addition, when using oil palm empty fruit bunches as herbaceous biomass, the pre-treated oil palm empty fruit bunches are supplied to the combustion furnace, and the residue obtained by squeezing nuclear oil from fiber and oil palm seeds squeezed from oil palm fruits PKS (Palm Kernel Shell) may also be supplied to the combustion furnace for mixed combustion. Even in the case of mixed combustion of the oil palm empty fruit bunch and other biomass discharged from the palm oil mill, potassium in the oil palm empty fruit bunch is greatly reduced, so that potassium is included. It is possible to prevent the occurrence of problems due to this, and the ratio of oil palm empty fruit bunches to the whole burning biomass can be greatly increased.

<Chlorine removal effect>
Some herbaceous biomass contains chlorine, and combustion of herbaceous biomass containing chlorine causes a problem that hydrogen chloride is generated and the heat recovery boiler is corroded. By using the pretreatment device according to this embodiment, the herbaceous biomass is first squeezed and dehydrated, and then subjected to the second squeeze dehydration to reduce potassium and greatly increase the chlorine in the herbaceous biomass. There is an effect that can be reduced. As a result, when using herbaceous biomass as fuel, corrosion of the heat recovery boiler due to chlorine can be prevented. Moreover, since the combustion gas introduced into the heat recovery boiler can be increased in temperature, the generated steam temperature can be increased and the power generation efficiency can be improved. Furthermore, since chlorine in herbaceous biomass is reduced, generation of dioxins can be suppressed.

<Second embodiment>
This embodiment is different in configuration from the first embodiment in which the press dewatering device is a screw press dewatering device in that the press dewatering device is a filter press dewatering device. Also in this embodiment, since the structure until herbaceous biomass is supplied to the pressing and dehydrating apparatus is the same as that of the first embodiment, the description will be omitted, and the description will focus on the structure of the pressing and dehydrating apparatus. Hereinafter, although the example which processes an oil palm empty fruit bunch as herbaceous biomass is demonstrated, the point which can process other herbaceous biomass, such as king glass, is the same as that of 1st embodiment.

  3 (A) to 3 (D) are longitudinal sectional views showing the configuration and operation of the pressing and dehydrating apparatus 20 according to the second embodiment of the present embodiment, and FIG. 3 (A) is a biomass supply process, FIG. 3 (B) shows a first press dehydration step and a second press dehydration step, FIG. 3 (C) shows a hydration step, and FIG. 3 (D) shows a biomass discharge step.

  The structure of the pressing and dewatering device 20 will be described in detail with reference to FIG. The press dewatering device 20 is configured by arranging a plurality of pairs of a filter plate 21 and a diaphragm filter plate 22 on a guard rail (not shown) in the plate thickness direction. FIG. 3D shows a pair of filter plates 21 and a diaphragm filter plate 22. In each pair, the diaphragm filter plate 22 can reciprocate on the guard rail by a tightening cylinder or the like. In this embodiment, in each pair, the diaphragm filter plate 22 is in a closed position (see FIGS. 3A to 3C) where it is in contact with the filter plate 21 and an open position separated from the filter plate 21 (FIG. 3D). )). Further, between the filter plate 21 and the diaphragm filter plate 22, a filtration chamber 20A that is a space for receiving the oil palm empty fruit bunch is formed.

  FIG. 3D shows a state in which the pair of filter plates 21 and the diaphragm filter plate 22 are in the open positions separated from each other. The filter plate 21 has a recess 21A formed on the surface facing the diaphragm filter plate 22, and the side plate surface (the surface facing the diaphragm filter plate 22) of the inner wall surface of the recess 21A functions as the filtration bed 21F. . The filtration bed 21F has a plurality of grooves 21B extending at right angles to the paper surface of FIG. 3D, and the plurality of grooves 21B communicate with each other. A supply port 21C for supplying water from an oil palm empty fruit bunch from the dispersing device 4 and a water supply unit (not shown) is formed through the filter plate 21 at a position above the recess 21A. A discharge port 21D for discharging compressed water to the outside is formed through the filter plate 21 at a position below the recess 21A. The supply port 21C communicates with the filtration chamber 20A, and the discharge port 21D communicates with the filtration chamber 20A and the plurality of grooves 21B.

  The filter bed 21F of the filter plate 21 is provided with a filter medium 23 so as to cover the plurality of grooves 21B. As will be described later, the filter medium 23 filters the compressed water of the empty palm bunch. Yes. The filter medium 23 is formed of, for example, a metal filter medium such as a filter cloth or a wedge wire filter.

  The diaphragm filter plate 22 has a recess 22 </ b> A corresponding to the recess 21 </ b> A of the filter plate 21 on the surface facing the filter plate 21. Above the recess 22A, an oil palm empty fruit bunch from the dispersing device 4 and a supply port 22C for supplying water from a water supply unit (not shown) are formed through the diaphragm filter plate 22. A discharge port 22D for discharging compressed water to the outside is formed through the diaphragm filter plate 22 at a position below the recess 22A.

  The supply port 22C and the discharge port 22D communicate with the filtration chamber 20A. The supply port 22C and the discharge port 22D communicate with the supply port 21C and the discharge port 21D of the filter plate 21 when the filter plate 21 and the diaphragm filter plate 22 are in the closed position (FIG. 3A). To (C)). The supply ports 22C and 22D are connected to each other between a plurality of pairs of the filter plate 21 and the diaphragm filter plate 22 by a single supply pipe (not shown). Oil palm empty fruit bunch and water are supplied to 20A. Further, in the concave portion 22A, as will be described later, an air port 22E through which compressed air is fed and discharged is formed through the side plate of the concave portion 22A (a plate portion whose plate surface faces the filter plate 21). ing. In the present embodiment, the oil palm empty fruit bunch and water are supplied from the supply port 21C to the filtration chamber 20A. The supply port 22C communicated with the supply port 21C in the closed position allows the oil palm empty fruit bunch and water from the supply port 21C to pass through another pair adjacent to the pair of the filter plate 21 and the diaphragm filter plate 22. Is supplied to the filtration chamber.

  In the recess 22A, a plate-shaped diaphragm filtration bed 24 that is accommodated and accommodated in the recess 22A is provided. The diaphragm filtration bed 24 is made of, for example, elastic rubber. The diaphragm filtration bed 24 is formed with a plurality of groove portions 22B extending at right angles to the paper surface of FIG. 3D on the surface facing the filter plate 21, and the plurality of groove portions 22B communicate with each other. . Further, the plurality of groove portions 22B communicate with the discharge port 22D when the diaphragm filtration bed 24 is in a pressing position described later (FIG. 3B).

  A filter medium 25 is provided on the surface of the diaphragm filter plate 22 where the groove 22B is formed so as to cover the groove 22B, and the filter medium 25 filters the compressed water of the oil palm empty fruit bunches. It has become. Similarly to the filter medium 23, the filter medium 25 is formed of a metal filter medium such as a filter cloth or a wedge wire filter.

  As seen in FIG. 3D, a space functioning as a diaphragm chamber 26 is formed between the side plate surface of the recess 22 </ b> A and the diaphragm filter plate 22. As will be described later, the diaphragm chamber 26 expands when compressed air is fed from the air port 22E (see FIG. 2B), and when the compressed air is discharged from the air port 22E, the diaphragm chamber. 26 contracts (see FIG. 3C).

  Hereinafter, the pretreatment of the oil palm empty fruit bunch by the squeezing and dehydrating apparatus 20 will be described with reference to FIGS. 3 (A) to 3 (D).

<Biomass supply process>
First, as seen in FIG. 3A, the diaphragm filter plate 22 is moved to the filter plate 21 side and brought to the closed position. As a result, the supply port 22C and the discharge port 22D of the diaphragm filter plate 22 communicate with the supply port 21C and the discharge port 21D of the filter plate 21, respectively. Next, the empty palm fruit tress P is put into the space between the filter medium 23 of the filter plate 21 and the filter medium 25 of the diaphragm filter plate 22, that is, the filtration chamber 20A, from the supply port 21C.

<First pressing dehydration process>
Next, as shown in FIG. 3B, the air for compression is supplied from the air port 22E of the diaphragm filter plate 22 to the diaphragm chamber 26 to expand the diaphragm chamber 26, and the diaphragm filtration bed 24 is moved to the filter plate 21. Move to the side. As a result, as shown in FIG. 3 (B), the diaphragm filtration bed 24 is brought to a pressing position where the oil palm empty fruit bunches P are squeezed, and the oil palm empty fruit bunches P are sandwiched between the filter medium 23 and the filter medium 25. And squeezed and dehydrated. The squeezed water squeezed out from the oil palm empty fruit bunches P is filtered by the filter media 23 and 25, and is discharged to the outside from the discharge ports 21D and 22D after passing through the plurality of grooves 21B and 22B. Since this compressed water contains potassium, the elution of potassium from the oil palm empty fruit bunches P is eliminated by discharging the compressed water.

  By squeezing and dehydrating the oil palm empty fruit buns P in this way, water containing potassium eluted from the oil palm empty fruit bunches P is removed, and by pressing and pressurizing, potassium is removed from the small pieces of the oil palm empty fruit bunches P. Moisture contained is leached, and the strip is softened, and the cell membrane is broken, and intracellular potassium is leached into the surrounding moisture.

<Hydrolysis step>
Next, as shown in FIG. 3 (C), by discharging the air for compression from the air port 22E and supplying water to the filtration chamber 20A from the water supply part (not shown) through the supply port 21C. The water is added to the oil palm empty fruit bunch (dehydrated herbaceous biomass) that has been squeezed and dehydrated in the first pressing step. The diaphragm filtration bed 24 moves toward the direction away from the filter plate 21 (to the right in FIG. 3C) due to the discharge of the air for compression, and the oil palm empty fruit tress P is added in the first pressure dehydration step. The pressure that had been released is released. Then, by adding water to the oil palm empty fruit bunches P, the oil palm empty fruit bunches P absorb moisture while expanding, so that the oil palm empty fruit bunches P absorb water quickly and are absorbed in a short time. At the same time, water spreads to the inside and the remaining potassium can be sufficiently eluted in the water.

  In the present embodiment, water is supplied from the supply port. However, instead of this, for example, water may be supplied from the drain port by using the drain port as the supply port. Further, a water supply system (not shown) may be separately provided in the filtration bed to supply water from the filtration bed.

<Second pressing dehydration process>
Next, as seen in FIG. 3 (B), as in the first squeezing and dewatering step, air for squeezing is supplied to the diaphragm chamber 26 to expand the diaphragm chamber 26, and the diaphragm filtration bed 24 is brought into the squeezing position. By bringing, the oil palm empty fruit bunches P are depressurized and dehydrated again. It is possible to further reduce the potassium content in the oil palm empty fruit bunch on the same principle as the first pressure dehydration by depressurizing and dehydrating the oil palm empty fruit bunch (hydrous herbaceous biomass) that has absorbed water and absorbed moisture. it can. As mentioned above, pre-processing is completed by processing an oil palm empty fruit bunch in a 1st pressing process, a hydration process, and a 2nd pressing dehydration process.

<Biomass discharge process>
As shown in FIG. 3 (D), the diaphragm filter plate 22 is moved in the direction away from the filter plate 21 (rightward in FIG. 3 (D)) to bring it into the open position, and compressed air from the air port 22E. And the diaphragm filtration bed 24 is moved into the recess 22 </ b> A of the filter plate 22. As a result, the filtration chamber 20A is largely opened, and the compressed and dehydrated oil palm empty fruit bunches P (dehydrated herbaceous biomass) are dropped and discharged out of the filtration chamber 20A.

  In this embodiment, the oil palm empty fruit bunches P supplied to the filtration chamber 20A of the squeezing and dehydrating device 20 are subjected to the first squeezing dehydration, the hydration and the second squeezing dehydration while remaining in the filtration chamber 20A. Oil palm empty fruit bunches P with reduced potassium content are discharged. Thus, since the three processes of the 1st press dehydration process, the hydration process, and the 2nd press dehydration process are performed by the one press dehydration apparatus 20, an installation is compact and an installation cost can be made low and it can drive | operate. Operation can be performed simply.

  Moreover, in this embodiment, although it was decided to perform two squeezing dehydration processes and one hydration process, the number of the squeezing dehydration processes and hydration processes provided in one squeeze dehydration apparatus was increased as needed. Also good. In this case, the pressing dehydration step and the hydration step are performed alternately.

10 Press dewatering device (screw press device)
DESCRIPTION OF SYMBOLS 11 1st press dehydration part 12 Water addition part 13 2nd press dehydration part 20 Press dehydration apparatus (filter press apparatus)
20A Filtration chamber

Claims (4)

A pretreatment device that performs pretreatment before using herbaceous biomass as fuel, gasification raw material or carbide raw material,
And squeezing and dewatering herbaceous biomass, then adding water, squeezing and dewatering to means have a squeezing and dewatering device which is structured in a single device again,
The press dewatering device is a screw press dewatering device that accepts herbaceous biomass, presses and dehydrates, presses and dehydrates the squeezed dehydrated herbaceous biomass transferred from the first press dewatering unit, and squeezes dehydrated herbaceous biomass. pretreatment apparatus herbaceous biomass, characterized by chromatic and a second compression dehydration unit to discharge again squeezing and dewatering dried herbaceous biomass hydro herbaceous biomass are. A pretreatment device that performs pretreatment before using herbaceous biomass as fuel, gasification raw material or carbide raw material,
A means for dehydrating and dehydrating herbaceous biomass, and then squeezing and dehydrating again has a squeezing and dehydrating device configured in one device,
The pressure dewatering device is a filter press dewatering device, and has a filtration chamber that receives herbaceous biomass in the gap between the filter media facing each other, and a water supply section that hydrates the dehydrated herbaceous biomass in the filtration chamber, after squeezing and dewatering herbaceous biomass acceptance, hydro from hydro supply unit to dehydration herbaceous biomass, again squeezed and dewatered pretreatment apparatus herbaceous biomass, characterized in that for discharging the dehydrated herbaceous biomass. A pretreatment method for performing pretreatment before using herbaceous biomass as fuel, gasification raw material or carbide raw material,
A first press dehydration step for receiving and squeezing herbaceous biomass in the upstream part of the screw press dehydrator, a hydration step for adding water to the dehydrated herbaceous biomass transferred from the upstream part in the middle part of the screw press dehydrator, and a screw press A pretreatment method for herbaceous biomass, comprising: a second squeezing and dehydrating step of squeezing and dehydrating again the herbaceous biomass transferred from the midstream part in the downstream part of the dehydrator. A pretreatment method for performing pretreatment before using herbaceous biomass as fuel, gasification raw material or carbide raw material,
The first press dehydration step of supplying herbaceous biomass to the filter chamber of the filter press dehydrator and squeezing and dehydrating, the hydration step of adding water to the dehydrated herbaceous biomass in the filter chamber, and pressing the hydrated herbaceous biomass in the filter chamber again A pretreatment method for herbaceous biomass, comprising a second squeezing dehydration step for dehydration.

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