Organic waste treatment system and treatment method

Abstract

[Problem] To provide a treatment system and a treatment method for organic waste. [Solution] The present invention comprises: a digestion tank 3 for digesting organic waste W1 from the inside of a water treatment facility 51A; a digested sludge circulation line L3 for circulating, to the digestion tank 3, a portion of the digested sludge W11 treated in the digestion tank 3 as circulating digested sludge W11a; a thermal reformer 2 for introducing an outside dehydrated cake 52B from a water treatment facility 51B outside the water treatment facility 51A, and performing a thermal reforming treatment; a controller 50 for controlling the operating conditions for the thermal reformer 2; and a thermally reformed substance introduction line L12 for introducing, into the digestion tank 3, a thermally reformed substance W12B reformed by the thermal reformer 2, wherein the controller 50 controls the pressure in a thermal reforming tank 11 of the thermal reformer 2 to be kept equal to or higher than the saturated water vapor pressure.

Description

【Technical Field】 【0001】 The present invention relates to a treatment system and a treatment method for organic waste. 【Background Art】 【0002】 For example, as a method for treating organic waste such as food waste, livestock manure, and sewage sludge in a water treatment facility, anaerobic digestion treatment using anaerobic organisms is known. In this anaerobic digestion treatment, organic waste such as sludge introduced into a digestion tank is subjected to solubilization, hydrolysis, and acid fermentation, and then methane fermentation is carried out to decompose the solid content into methane gas and carbon dioxide, thereby reducing the volume of the solid content. The methane gas is used as energy. 【0003】 Before performing anaerobic digestion treatment, heat solubilization treatment may be performed on the sludge. Heat solubilization treatment is a treatment for heating sludge (organic waste) to a predetermined temperature and hydrolyzing the solid content. For example, Patent Document 1 describes a technique for heat solubilizing by supplying high-temperature steam to sludge (organic waste) containing an organic material. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Japanese Patent Translation of PCT International Publication No. 2003-500208 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 By the way, as a method for treating organic waste such as sewage sludge, when a digestion tank is installed to treat a dewatered cake, the digestion tank is large, and there is a problem that it is difficult for each local government to install a digestion tank for each treatment plant. 【0006】 Therefore, when dewatered cake is transported from other processing plants and consolidated for processing in one location, a large amount of dewatered cake brought in increases the amount of steam used for thermal reforming, and this heat is supplied to the digestion tank, which raises the temperature of the digestion tank. This is because the entire process from the heat reforming unit to the digestion tank is conducted in a sealed environment, and if a large amount of steam is required for solubilization, the temperature of the solubilized sludge transported to the digestion tank will rise. 【0007】 On the other hand, methods for cooling the thermosolubilized sludge, whose temperature has risen, are also being considered, but this would require separate equipment and utilities such as electricity. Furthermore, it is possible to lower the temperature by releasing steam from a sealed heat reformer, but this results in energy loss, and releasing steam to the outside also creates problems such as the release of odors and other substances into the outside environment. 【0008】 The present invention provides an organic waste treatment system and treatment method that allows for the treatment of dewatered cake from water treatment facilities outside of the water treatment facility, as well as from within the water treatment facility, in a single location when treating organic waste such as sewage sludge. [Means for solving the problem] 【0009】 The first invention relates to a digester for digesting organic waste from within a water treatment facility, A digested sludge circulation line that circulates a portion of the digested sludge processed in the digester back to the digester as circulating digested sludge, A thermal reforming apparatus that introduces off-site dewatered cake from the water treatment facility outside the aforementioned water treatment facility and performs thermal reforming treatment, A control device for controlling the operating conditions of the heat reforming apparatus, A thermal reforming material introduction line for introducing the thermally reformed material modified by the thermal reforming apparatus into the digester, Equipped with, In the control device, the pressure inside the heat reforming tank of the heat reforming apparatus is controlled to be maintained at or above the saturated water vapor pressure. The aforementioned heat reforming apparatus is A heat reforming tank for performing heat reforming treatment on sludge, A steam supply device that supplies steam to the sludge in the heat reforming tank, A gas discharge line for discharging gas from inside the heat reforming tank to the solubilized sludge discharged from the heat reforming tank, A pressure sensor for measuring the pressure inside the heat reforming tank, A pressure control valve for opening and closing the aforementioned gas discharge line, The system includes pressure control means for adjusting the opening degree of the pressure control valve so that the measurement value of the pressure sensor becomes a target value, The thermal reforming tank is equipped with an outlet pipe for discharging the solubilized sludge, The organic waste treatment system is characterized in that the gas discharge line is connected to the outlet pipe. 【0010】 The second aspect of the present invention is: A digester tank for digesting organic waste from within the water treatment facility, A digested sludge circulation line that circulates a portion of the digested sludge processed in the digester back to the digester as circulating digested sludge, A thermal reforming apparatus that introduces off-site dewatered cake from the water treatment facility outside the aforementioned water treatment facility and performs thermal reforming treatment, A control device for controlling the operating conditions of the heat reforming apparatus, A thermal reforming material introduction line for introducing the thermally reformed material modified by the thermal reforming apparatus into the digester, Equipped with, In the control device, the pressure inside the heat reforming tank of the heat reforming apparatus is controlled to be maintained at or above the saturated water vapor pressure. A sludge dewatering machine that dewaters a portion of the aforementioned digested sludge to produce an in-house dewatered cake, The system includes a dewatered cake introduction line for introducing the dewatered cake from the sludge dewatering machine into the heat reforming device, The heat reforming apparatus is used to heat reform the dewatered cake from within the facility and the dewatered cake from outside the facility. The aforementioned heat reforming apparatus is A heat reforming tank for performing heat reforming treatment on sludge, A steam supply device that supplies steam to the sludge in the heat reforming tank, A gas discharge line for discharging gas from inside the heat reforming tank to the solubilized sludge discharged from the heat reforming tank, A pressure sensor for measuring the pressure inside the heat reforming tank, A pressure control valve for opening and closing the aforementioned gas discharge line, The system includes pressure control means for adjusting the opening degree of the pressure control valve so that the measurement value of the pressure sensor becomes a target value, The thermal reforming tank is equipped with an outlet pipe for discharging the solubilized sludge, The organic waste treatment system is characterized in that the gas discharge line is connected to the outlet pipe. The third aspect of the present invention is an organic waste treatment system characterized in that, in the first or second aspect of the present invention, the thermal reforming conditions of the thermal reforming apparatus are 120 to 150°C, and the digestion conditions of the digester are 30 to 60°C. The fourth aspect of the present invention is the first or second aspect of the present invention, further comprising an outlet pipe for discharging the solubilized sludge from the heat reforming tank, The outlet pipe has its inlet portion inserted into the inside of the heat reforming tank. The organic waste treatment system is characterized in that the pipe inlet is positioned opposite the bottom of the heat reforming tank. The fifth aspect of the present invention relates to the first or second aspect of the present invention, and includes a liquid level sensor that measures a physical quantity correlated with the liquid level height of the sludge in the heat reforming tank, A liquid level control valve that opens and closes the outlet pipe, before The organic waste treatment system is characterized by comprising: liquid level control means for adjusting the opening degree of the liquid level control valve so that the measured value of the liquid level sensor becomes a target value. The sixth aspect of the present invention is, in the fourth aspect of the present invention, The inner diameter of the pipe of the heat reforming tank is D, The inner diameter of the outlet pipe is d, Let X be the length from the inner wall surface of the heat reforming tank chamber at the pipe inlet to the lower end of the tip portion. When the upper edge angle of the tip portion in a side view is denoted as θ, X: 0~1 / 2D θ:30~85 degrees d: Inner diameter 65mm~1 / 2D WL: (Sludge volume) / (Tank volume) = 1 / 5 to 4 / 5 The organic waste treatment system described in 4 is characterized by having the following relationship. The seventh aspect of the present invention includes, in the first or second aspect of the present invention, an input line L6 for introducing off-site dewatered cake 52B from an off-site water treatment facility into the heat reforming tank, The input line L6 is connected to the lower end of the heat reforming tank 11 via a mixing pot 12 to which a discharge nozzle 20 is connected. The mixing pot 12 receives high-temperature first steam S over the off-field dewatered cake 52B. 1 The organic waste treatment system according to claim 1 or 2, characterized in that it incorporates a first steam pipe 15 for injecting a vapor. [Effects of the Invention] 【0011】 According to the present invention, when processing organic waste such as sewage sludge, dewatered cake from both within and outside the water treatment facility can be collected and processed in one location. Furthermore, variations in the thermal reforming treatment become less likely, and energy consumption during the digestion treatment of thermally reformed sludge can be reduced. [Brief explanation of the drawing] 【0012】 [Figure 1] This is a conceptual diagram of the organic waste treatment system according to Embodiment 1. [Figure 2] This is a processing flow diagram of the organic waste treatment system of Embodiment 1. [Figure 3] This is a cross-sectional view of the thermal reforming apparatus of Embodiment 1. [Figure 4] This is a cross-sectional view of another thermal reforming apparatus from Embodiment 1. [Figure 5] This is a processing flow diagram of the organic waste treatment system of Embodiment 2. [Modes for carrying out the invention] 【0013】 [Embodiment 1] Figure 1 is a schematic diagram of the organic waste treatment system according to Embodiment 1. Figure 2 is a treatment flow diagram of the organic waste treatment system of Embodiment 1. Figure 3 is a cross-sectional view of the thermal reforming apparatus of Embodiment 1. As shown in FIG. 1, in the organic waste treatment system 100A of Embodiment 1 (hereinafter, also simply referred to as "treatment system"), when treating organic waste such as sewage sludge, not only the organic waste W1 in the in-plant water treatment facility (hereinafter, referred to as "in-plant water treatment facility" or "water treatment facility (in-plant)") 51A but also the off-site dewatered cake 52B from the off-site water treatment facility (hereinafter, referred to as "off-site water treatment facility" or "water treatment facility (off-site)") 51B is treated in a single digestion tank 3. 【0014】 That is, as shown in FIG. 1, the organic waste treatment system 100A according to the present embodiment includes a digestion tank 3 that introduces and digests the organic waste W1, which is sludge from the in-plant water treatment facility 51A, through an introduction line L1, and a discharge line L2 that discharges the digested sludge W 11 from the digestion tank 3, a digested sludge circulation line L3 that circulates a part of the digested sludge W 11 as digested sludge W 11a back to the digestion tank 3, a thermal reforming device 2 equipped with a thermal reforming tank 11 that thermally reforms the off-site dewatered cake 52B from the off-site water treatment facility 51B, and a thermal reformed product W 12B reformed in the thermal reforming tank 11 is introduced into the digestion tank 3 through a thermal reformed product introduction line L 12 . Here, in the present invention, "thermal reforming" means solubilizing sludge (dewatered cake) by the heat of steam (S) supplied from the outside, and includes a state where it is not completely solubilized. In FIG. 1, reference numeral 4 denotes a steam supply device, S denotes high-temperature steam, L6 denotes an off-site dewatered cake input line (also referred to as "input line"), L 11 denotes a steam introduction line, L 13 denotes a gas discharge line (described later), and L 14 denotes a biogas line that discharges biogas (CH4) as digested gas from the digestion tank 3, respectively. 【0015】 Also, as shown in FIG. 2, the digested sludge W 11After being dewatered in the sludge dewatering machine 6, the dewatered cake 52A is discharged to the outside as a dry material via the dewatered cake discharge line L4. The dewatered filtrate 53 from the sludge dewatering machine 6 is also discharged as return water via the drainage line L5. 【0016】 Here, the off-site dewatered cake 52B, which has been treated as sludge at the water treatment facility 52B where no digester tank is installed, is transported and brought in by means of transport (e.g., trucks). The off-site dewatered cake 52B that is brought in is fed in from the input section 55 and introduced into the heat reforming tank 11 via the input line L6. 【0017】 Steam S is introduced into the heat reforming tank 11 by a steam supply device 4 to heat reform the sludge. The heat reformed material W is then heat reformed (partially solubilized) in the heat reforming tank 11. 12B The thermal reforming material introduction line L is for the digester 3. 12 It is being implemented through [a specific method / platform]. 【0018】 In this embodiment, the control device 50 controls the pressure inside the heat reforming tank 11 to be maintained at or above the saturated water vapor pressure. When off-site dewatered cake 52B is transported from another treatment plant (off-site water treatment facility 51B) and consolidated in one location for large-scale processing, the amount of steam S required for thermal reforming increases. As a result, the increased amount of heat from the introduced steam is added to the digester tank 3, causing the temperature of the digester tank 3 to rise. 【0019】 In other words, if you want to perform thermal reforming at a low temperature (for example, 120°C) to prevent the heat rise described above, setting the vapor pressure of the corresponding water vapor S to 0.1 MPa (gauge pressure) will result in the thermal reformed material W 12B The extrusion pressure decreases. As a result, the thermal reformed material W from the thermal reforming tank 11 12B Discharge into digester tank 3 becomes difficult. 【0020】 Therefore, in this embodiment, the internal pressure in the tank of the thermal reforming apparatus 2 is controlled to a set pressure of 0.2 to 0.3 MPa, thereby reducing the thermal reforming sludge W from the thermal reforming tank 11. 12B It facilitates the discharge of waste. 【0021】 An example of this control will be further explained using Figures 2 and 3. As shown in Figure 2, the organic waste treatment system 100A includes a digester (device) 3 that digests the first organic waste W1, which is sludge from the on-site water treatment facility 51A, and the digested sludge W processed in the digester 3. 11 Discharge line L2 discharges the digested sludge W, and a branch line from discharge line L2 discharges the digested sludge W. 11 A portion of the sludge is recycled W 11a A sludge circulation line L3 that circulates the sludge to the digester 3, a thermal reforming device 2 that introduces off-site dewatered cake 52B from the off-site water treatment facility 51B via the off-site dewatered cake input line L6 and performs thermal reforming treatment, a control device 50 that controls the operating conditions of the thermal reforming device 2, and thermal reformed material W that has been reformed by the thermal reforming device 2. 12B The thermal reforming material introduction line L introduces the material into digester tank 3. 12 The device comprises the above, and the control device 50 controls the pressure inside the heat reforming tank 11 of the heat reforming apparatus 2 to be maintained at or above the saturated water vapor pressure. 【0022】 Here, the processing temperature in the heat reforming tank 11 is controlled to 110-150°C. Furthermore, the gauge pressure at a processing temperature of 120°C is controlled to approximately 0.1-0.4 MPa. In other words, the control device 50 sets the control setting value (X) for the heat reforming tank 11 to a value higher than 0.1 MPa (X = 0.2 to 0.3 MPa). This control is also performed on the gas discharge line L, as will be described later. 13 The pressure is regulated by a pressure regulating valve 31a installed between them. 【0023】 (Processing system 100A) An example of the configuration of the organic waste treatment system 100A according to the present invention will be explained with reference to Figure 2. As shown in Figure 2, the heat reforming apparatus 2 of the organic waste treatment system 100A includes a mixing pot 12 that performs pretreatment on the off-site dewatered cake 52B from outside the site, a heat reforming tank 11 that performs heat reforming on the off-site dewatered cake 52B discharged from the mixing pot 12, and a steam introduction line L into the heat reforming tank 11 and the mixing pot 12. 11 (Steam introduction line L) 11-1 , steam introduction line L 11-2 A steam supply device 4 that supplies steam S (S1, S2) via a ) and a gas discharge line L that discharges gas 31 from the heat reforming tank 11. 13 And, gas discharge line L 13 It is equipped with a pressure regulating valve 31a that opens and closes, and 【0024】 Figure 3 is a system diagram of the thermal reforming apparatus 2, which provides a concrete representation of the system configuration. As shown in Figure 3, the thermal reforming apparatus 2 of this embodiment includes a pressure sensor 32 for measuring the pressure inside the thermal reforming tank 11, a pressure control means 33 for adjusting the opening degree of the pressure control valve 31a so that the measurement value of the pressure sensor 32 becomes a target value, and thermal reforming material W from the thermal reforming tank 11. 12B The system includes an outlet pipe 24 for discharging the sludge, a liquid level sensor 34 for measuring a physical quantity correlated with the liquid level of the sludge in the heat reforming tank 11, a liquid level control valve 24a for opening and closing the outlet pipe 24, and a liquid level control means 35 for adjusting the opening degree of the liquid level control valve 24a so that the measurement value from the liquid level sensor 34 becomes a target value. 【0025】 Referring to Figure 2, an example of the processing flow of the organic waste processing system 100A will be explained. First, the new organic waste W1 to be processed on-site is put into the digester 3. Examples of organic waste W1 include organic sludge such as sewage sludge and septic tank sludge, food waste, kitchen waste, and livestock manure. In the digester 3, the organic waste W1 is subjected to methane fermentation (digestion treatment) by anaerobic methane-fermenting bacteria. 【0026】 The operating temperature of the digester 3 is set appropriately, taking into consideration the type of methane fermentation bacteria and the doubling time. During methane fermentation, biogas G, which is a digester gas consisting mainly of CH4 and CO2, is generated from the digester 3. Some or all of this biogas G is sent out as fuel for the steam boiler of the steam supply device 4. The steam supply device 4 uses this biogas G as fuel to generate high-temperature steam S and supplies the high-temperature steam S (S1, S2) to the heat reforming tank 11 and mixing pot 12 of the heat reforming device 2. 【0027】 Alternatively, instead of a steam boiler, biogas G may be supplied to a digester gas generator to generate electricity, and high-temperature steam recovered from the waste heat of the digester gas generator (consisting of a digester gas engine and a generator) may be supplied to the heat reforming tank 11 and the mixing pot 12. 【0028】 Digested sludge W is organic waste that has been digested in digester 3. 11 The digested sludge W is stored in the digested sludge storage tank 5 via the discharge line L2. 11 Part of W 11a The remaining sludge W is then circulated to the digester tank 3 via the circulation line L3. 11 The sludge is temporarily stored in the digested sludge storage tank 5 and then sent to the sludge dewatering machine 6. The sludge dewatering machine 6 consists of, for example, a centrifugal dewatering machine (decanter), a screw-type dewatering machine, a belt-press dewatering machine, etc. The dewatered filtrate 53 discharged from the sludge dewatering machine 6 is sent to a water treatment system (not shown). 【0029】 The thermal reforming unit 2 thermally reforms the off-site dewatered cake 52B that is fed into it, and the thermally reformed sludge W is produced. 12B This is the thermal reformer introduction line L 12 It is sent to the digestive tank 3 via [this method]. 【0030】 Furthermore, digested sludge W is collected from digested sludge storage tank 5. 11 In some cases, the entire amount may be sent to the sludge dewatering machine 6. Alternatively, digested sludge W may be sent from the digester tank 3 without the need for a digested sludge storage tank 5. 11In some cases, the sludge may be sent directly to the sludge dewatering machine 6. The residence time of the sludge in the heat reforming unit 2 is, for example, about 10 to 60 minutes. 【0031】 (Thermal reforming unit 2) Next, the configuration of the thermal reforming apparatus will be described in detail with reference to Figures 3 and 4. Figure 3 is a cross-sectional view of the thermal reforming apparatus of Embodiment 1. Figure 4 is a cross-sectional view of another thermal reforming apparatus of Embodiment 1. As shown in Figure 3, in the thermal reforming apparatus 2A of this embodiment, pretreatment of the off-field dewatered cake 52B is performed in the mixing pot 12, and steam S1 is introduced into the mixing pot 12. Thermal reforming treatment is then performed on this pretreated off-field dewatered cake 52B in the thermal reforming tank 11. In this embodiment, the steam supply device 4 supplies first steam (S1) to the off-field dewatered cake 52B in the heat reforming tank 11, and also supplies second steam (S2) to the off-field dewatered cake 52B in the mixing pot 12. 【0032】 The mixing pot 12 is connected to the downstream end of the input line L6 for the off-field dewatered cake 52B. The mixing pot 12 comprises a substantially cylindrical pot body 14 arranged as part of the input line L6, and a first steam pipe 15 that supplies first steam (S1) inserted into the interior of the pot body 14 from the circumferential surface of the pot body 14. 【0033】 The pot body 14 is formed with a larger diameter in the center and gradually narrows in diameter towards the upper and lower ends. The flange 13 at one end (lower end) of the pot body 14 is bolted to the flange 7a of the supply pipe 7. The opening diameter at the lower end of the pot body 14 is approximately the same as the inner diameter of the supply pipe 7, and the opening diameter at the upper end is approximately the same as the inner diameter at the lower end of the discharge nozzle 20, which will be described later. In this embodiment, there are two first steam pipes 15, which are inserted into the pot body 14 so as to be offset from each other in the axial direction of the pot body 14 and extending in a direction perpendicular to the axial direction of the pot body 14. The tip of each first steam pipe 15 is fitted into a steam pipe support portion 16 recessed in the inner circumferential surface of the pot body 14. 【0034】 The heat reforming tank 11 is a sealed, cylindrical body. When the set temperature (target temperature) of the gas phase inside the heat reforming tank 11 is set to, for example, 110°C to 150°C, preferably 120°C to 140°C, the set pressure is approximately 0.2 to 0.7 MPa, preferably 0.3 to 0.5 MPa. 【0035】 A large-diameter drain section 18 is attached coaxially to the lower end of the heat reforming tank 11, and a discharge nozzle 20 is coaxially arranged inside this drain section 18. The discharge nozzle 20 consists of a tubular member with an open lower end and is connected to the upstream end of the mixing pot 12. The flange 21 at the lower end of the discharge nozzle 20 is bolted to the flange 22 at the upper end of the pot body 14. The discharge nozzle 20 is formed with a slightly larger diameter around its upper end than the diameter of the pipe near its lower end and is positioned at the bottom of the heat reforming tank 11. The upper end of the discharge nozzle 20 is closed without opening. Multiple small-diameter nozzle holes 23 are drilled around the upper end (discharge end) of the large-diameter discharge nozzle 20 at equal intervals in the circumferential direction. In other words, the multiple nozzle holes 23 are formed at equal intervals around the axis O of the heat reforming tank 11. The diameter of the nozzle holes 23 is, for example, about 15 millimeters. 【0036】 The surrounding wall of the heat reforming tank 11 is made of heat reforming material W. 12B An outlet pipe 24 is installed for discharging the contents to the outside. The outlet pipe 24 is connected to the thermal reformer introduction line L 12 It constitutes a part of the system. A liquid level control valve 24a is attached to the outlet pipe 24 to open and close the outlet pipe 24. The liquid level control valve 24a is, for example, an air-operated ball valve. 【0037】 A liquid level sensor 34 is mounted on the side of the heat reforming tank 11. The liquid level sensor 34 measures a physical quantity that correlates with the liquid level of the sludge in the heat reforming apparatus 2A. The liquid level sensor 34 in this embodiment is of the differential pressure type and includes a sensor that measures the pressure of the gas phase in the heat reforming tank 11 and a sensor that measures the pressure of the liquid phase (sludge) in the heat reforming tank 11. The measurement results of the liquid level sensor 34 are output to the liquid level control means 35. 【0038】 The liquid level control means 35 adjusts the opening of the liquid level control valve 24a according to the measurement value from the sludge liquid level sensor 34, adjusting the sludge liquid level to the target value. The liquid level control means 35 transmits a control signal to the drive unit of the liquid level control valve 24a. 【0039】 At the top of the heat reforming tank 11 is a gas discharge line L through which the gas 31 is discharged. 13 A pressure sensor 32 is attached to the gas discharge line L. 13 One end of it is in communication with the top 11a of the heat reforming tank 11. Also, the gas discharge line L 13 The other end is connected to the heat-modified material W of the liquid level control valve 24a interposed in the outlet pipe 24. 12B It is connected to the discharge destination side. Also, gas discharge line L 13 This gas discharge line L 13 A pressure regulating valve 31a is installed to open and close the valve. The pressure regulating valve 31a is, for example, an air-operated regulating valve. 【0040】 The pressure sensor 32 measures the pressure in the gas phase within the thermal reforming tank 11. The measurement result from the pressure sensor 32 is output to the pressure control means 33. The pressure control means 33 adjusts the opening of the pressure regulating valve 31a so that the measurement value from the pressure sensor 32 becomes the target value. In other words, the pressure in the gas phase of the heat reforming tank 11 is controlled by the pressure control means 33. By controlling the pressure sensor 32 so that its reading reaches the target value (set pressure), the saturated water vapor pressure in the gas phase within the heat reforming tank 11 can be kept constant, thereby maintaining the temperature in the gas phase at a temperature corresponding to the saturated water vapor pressure. 【0041】 In this embodiment, the steam supply device 4 includes a steam injection pipe 25 that supplies high-temperature second steam S2 into the heat reforming tank 11, separate from the mixing pot 12 and steam pipe 15. The steam injection pipe 25 is attached to the peripheral wall near the bottom of the heat reforming tank 11. Multiple steam injection holes 26 are drilled in the steam injection pipe 25. The diameter of the steam injection holes 26 is, for example, about 6 millimeters. Here, the temperature range of the high-temperature second water vapor S2 is preferably, for example, 110°C to 180°C. 【0042】 According to this embodiment, in a thermal reforming tank 11 that continuously supplies dewatered cake from an external source to a thermal reforming device 2A for thermal reforming, the temperature inside the tank is set to, for example, a range of 120 to 140°C, and the pressure inside the thermal reforming tank 11 is controlled to be maintained at or above the saturated water vapor pressure. This allows the solubilized sludge from the thermal reforming tank 11 to be discharged without installing a pump for sludge transfer to a digestion tank near the outlet of the thermal reforming tank. 【0043】 (Methods for disposing of organic waste) Next, we will explain the method for processing organic waste. The method for processing organic waste involves a supply process, a measurement process, and a control process. 【0044】 The supply process involves supplying steam generated in the steam boiler of the steam supply device 4 as a heat source to the heat reforming device 2A (heat reforming tank 11 and mixing pot 12). After the heat reforming tank 11 reaches a predetermined pressure, the off-field dewatered cake 52B is introduced into the heat reforming device 2A, and heat reforming is started within a predetermined temperature range. 【0045】 Furthermore, the total amount of high-temperature first steam S1 and high-temperature second steam S2 supplied to the heat reforming tank 11 is the amount supplied to the heat reforming tank 11 and the gas discharge line L 13 Taking into account heat dissipation and exhaust from the outside, it is preferable to supply a slightly larger amount than the amount required to heat the off-site dewatered cake 52B. Specifically, the increment amount, when the amount of high-temperature steam required for heating is set to 100% by mass, is, for example, 3% to 50% by mass. Here, the temperature range of the high-temperature first water vapor S1 is preferably, for example, 110°C to 180°C. 【0046】 The off-site dewatered cake 52B, transported by the input line L6, is directly mixed in the mixing pot 12 with high-temperature first steam S1 injected from the steam injection holes 17 of the first steam pipe 15. This mixture heats the cake and adds condensed water, reducing its viscosity. The temperature of the off-site dewatered cake 52B in the input line L6 is approximately 25-35°C. The off-site dewatered cake 52B, whose viscosity has decreased in the mixing pot 12, is then introduced into the thermal reforming tank 11 via the discharge nozzle 20 as treated sludge. The treated sludge introduced into the thermal reforming tank 11 is thermally reformed by high-temperature second steam S2 injected from the steam injection holes 26 of the steam injection pipe 25. After a predetermined residence time, it is discharged from the outlet pipe 24 and introduced into the thermal reforming material introduction line L6. 12 It is transported to the digestive tank 3 via [this method]. 【0047】 The measurement process involves continuously measuring the pressure in the gas phase within the thermal reforming tank 11 using a pressure sensor 32. The measurement values ​​from the pressure sensor 32 are sent to the pressure control means 33. 【0048】 The control process involves controlling the opening of the pressure control valve 31a so that the pressure in the gas phase of the heat reforming tank 11, as measured in the measurement process, reaches the target value. If the pressure in the heat reforming tank 11 exceeds the target value, the opening of the pressure control valve 31a is increased to release the gas (gas containing water vapor) from the heat reforming tank 11 to the gas discharge line L 13 The waste is released to the outlet pipe 24 via this. If the pressure inside the heat reforming tank 11 falls below the target value, the pressure inside the heat reforming tank 11 is increased by reducing the opening of the pressure control valve 31a or closing it completely. By controlling the pressure in the gas phase of the heat reforming tank 11 to the target value, the heat reformed sludge W is released from the heat reforming tank 11. 12B It facilitates the discharge of waste. 【0049】 According to the heat reforming apparatus 2A described above, based on the measured pressure of the gas phase in the heat reforming tank 11, the gas (gas containing water vapor) in the heat reforming tank 11 is introduced into the heat reforming material introduction line L 12 Since the water is discharged outside the heat reforming tank 11 through this outlet, the pressure inside the heat reforming tank 11 can be kept constant. 【0050】 Also, gas discharge line L 13 The gas (waste heat) discharged outside the heat reforming tank 11 through this process is the heat reformed material W discharged from the heat reforming tank 11. 12B Because it is supplied to, the thermal reformer W 12B This allows for heating, and consequently, reduces the energy consumption required to heat the digester tank 3. 【0051】 Furthermore, in this embodiment, the gas (waste heat) from the heat reforming tank 11 is discharged through the gas discharge line L 13 The heat reformed material W inside the outlet pipe 24 is passed through it. 12B To supply to the thermal reformer W, heat loss is minimized. 12B It can be heated efficiently. In other words, the heat-modified material W 12B This can be used as a heat source for the digester tank 3. 【0052】 Furthermore, the thermal reforming unit 2A can maintain a constant liquid level in the thermal reforming tank 11 by adjusting the opening of the liquid level control valve 24a, thus reducing variations in the thermal reforming process. This makes it possible to reduce the energy consumption when digesting the thermal reformed sludge. 【0053】 In conventional facilities that process organic waste, dewatered sludge (dewatered cake) was incinerated if it was not subjected to thermal reforming treatment. However, with the increasing demand for CO2 reduction as a measure against global warming, there is now a trend towards avoiding the incineration of dewatered cake. By consolidating and processing dewatered cake from outside the facility in a water treatment facility equipped with a digestion treatment system, as in this embodiment, it becomes possible to contribute to measures against global warming. 【0054】 Figure 4 also shows a modified example of a thermal reforming apparatus. In the thermal reforming apparatus 2A shown in Figure 3, the thermal reforming material W is inserted inside the outlet pipe 24 shown in Figure 3. 12B The shape of the pipe inlet section 24b into which the fuel is introduced is an upward-facing opening. In contrast, in the thermal reforming apparatus 2B shown in Figure 4, the thermal reformed material W in the outlet pipe 24 12B The tip of the pipe inlet 24b inserted into the interior for introduction is cut diagonally downwards. That is, if the outlet pipe 24 is circular, the cut surface will be elliptical, and the elliptical opening is positioned to face the bottom of the heat reforming tank 11. 【0055】 Here, in the heat reforming apparatus 2B shown in Figure 4, if we let D be the inner diameter of the pipe of the heat reforming tank 11, X be the length between the side wall 11c (point a) of the heat reforming tank 11 and the lower end (point b) of the tip of the pipe inlet 24b inserted into the outlet pipe 24, d be the inner diameter of the outlet pipe 24, and θ be the angle of the tip of the pipe inlet 24b, It is preferable to have the following relationship. X: 0~1 / 2D θ:30~85 degrees d: Inner diameter 65mm~1 / 2D WL: (Sludge volume) / (Tank volume) = 1 / 5 to 4 / 5 【0056】 Here, d is defined as an inner diameter of 65mm to 1 / 2D for the following reasons. Because the sludge to be discharged has a high solid content of 5-20 wt%, it is difficult to discharge it through an inner diameter of 65 mm or less, while making it 1 / 2D or larger makes tank fabrication difficult. 【0057】 The side view upper edge angle θ of the pipe inlet portion 24b is not particularly limited, and any tip opening shape that can face the bottom 11b of the heat reforming tank 11 is acceptable, and its cutting shape can be appropriately designed and modified. For example, 30 to 85 degrees is preferred, and 45 to 75 degrees is even more preferred. In this embodiment, the side view upper edge angle θ of the pipe inlet portion 24b is set to approximately 60 degrees. 【0058】 Here, if the upper edge angle θ of the pipe inlet 24b in a side view is outside the range of 30 to 85 degrees, the ratio of the area of ​​the discharge port to the area of ​​the flow path of the outlet pipe 24 is undesirable in terms of sludge discharge. 【0059】 Furthermore, for example, an embodiment can be adopted in which the circular pipe used in Figure 3 (with an upward-facing funnel-shaped outlet opening) is rotated 180 degrees so that the funnel-shaped outlet opening faces the bottom 11b of the heat reforming tank 11. 【0060】 Furthermore, it is preferable that the protruding length X of the outlet pipe 24 inserted into the heat reforming tank 11 be 1 / 2 or less of the inner diameter D of the heat reforming tank 11. Here, the protruding length X is preferably set to be 1 / 2 or less of the inner diameter D of the heat reforming tank 11, as this facilitates maintenance of the outlet of the outlet pipe 24. 【0061】 Furthermore, WL is preferably calculated as (sludge volume) / (tank volume), for example, 1 / 5 to 4 / 5. 【0062】 By limiting the values ​​as described above, when thermally solubilizing a highly viscous thermal modifier W in a temperature range of 150°C or less, 12B Since it is necessary to discharge the heat reformed material W from inside the heat reforming tank 11, 12B This makes it easier to discharge the waste. Furthermore, by keeping the values ​​within this range, a gas phase can be provided within the tank 11, making it easy to manage the temperature and pressure of the tank 11. 【0063】 [Embodiment 2] Figure 5 is a flow chart of the organic waste treatment system of Embodiment 2. Note that components identical to those in Embodiment 1 are denoted by the same reference numerals, and their descriptions are omitted. As shown in Figure 5, the organic waste treatment system 100B is the same as the organic waste treatment system 100A of Embodiment 1, where digested sludge W 11The system includes a sludge dewatering machine 6 that dewaters a portion of the sludge to produce an in-house dewatered cake 51A, and a dewatered cake introduction line L7 that introduces the in-house dewatered cake 52A from the sludge dewatering machine 6 to the heat reforming unit 2 (2A, 2B). This dewatered cake introduction line L7 is connected to an off-site dewatered cake input line L6, and the in-house dewatered cake 52A and off-site dewatered cake 52B are introduced into the heat reforming tank 11. In the heat reforming tank 11, the in-house dewatered cake 52A and off-site dewatered cake 52B are mixed and both are heat reformed. 【0064】 This allows the in-house dewatered cake 52A and the off-site dewatered cake 52B to be integrated and subjected to thermal reforming treatment in the thermal reforming tank 11. 【0065】 Although embodiments of the invention have been described above, the design can be modified as appropriate without violating the spirit of the present invention. For example, the gas discharge line L 13 The system may also be configured to connect to the digester tank 3, allowing the gas in the heat reforming tank 11 to escape into the digester tank 3. 【0066】 Furthermore, the thermal reforming apparatus 2 (2A, 2B) in this embodiment is merely an example, and the apparatus is not particularly limited as long as it has a configuration that produces substantially the same effects as this configuration. [Industrial applicability] 【0067】 The present invention is applicable to organic waste treatment systems and treatment methods in general. [Explanation of Symbols] 【0068】 100A, 100B Organic Waste Treatment System 2(2A, 2B) Thermal reformer 3 Digestion tank 4. Steam supply device 11. Heat reforming tank 12 Mixing pots 15. First steam pipe 24 Outlet pipe 24a Liquid level control valve 24b Pipe inlet 25 water vapor injection tubes 31 Gases 31a Pressure regulating valve 32 Pressure Sensor 33 Pressure control means 34 Liquid level sensor 35 Liquid level control means 51A On-site water treatment facilities (On-site water treatment facilities) 51B Off-site water treatment facilities 52A Dehydrated cakes on site 52B Off-field dehydrated cake 55 Insertion section S(S1,S2) High-temperature steam S1 High-temperature first steam S2 High-temperature second steam W1 Organic Waste W 11 Digested sludge W 12B Thermal reformers L1 introduction line L2 discharge line L3 Digestive Sludge Circulation Line L4 Dewatered Cake Discharge Line L5 drainage line L6 Off-Track Dewatered Cake Input Line (Input Line) L7 Dehydration Cake Introduction Line L 11 Steam introduction line L 12 Thermal reformer introduction line L 13 Gas discharge line

Claims

[Claim 1] A digester tank for digesting organic waste from within the water treatment facility, A digested sludge circulation line that circulates a portion of the digested sludge processed in the digester back to the digester as circulating digested sludge, A thermal reforming apparatus that introduces off-site dewatered cake from the water treatment facility outside the aforementioned water treatment facility and performs thermal reforming treatment, A control device for controlling the operating conditions of the heat reforming apparatus, A thermal reforming material introduction line for introducing the thermally reformed material modified by the thermal reforming apparatus into the digester, Equipped with, In the control device, the pressure inside the heat reforming tank of the heat reforming apparatus is controlled to be maintained at or above the saturated water vapor pressure. The aforementioned heat reforming apparatus is A heat reforming tank for performing heat reforming treatment on sludge, A steam supply device that supplies steam to the sludge in the heat reforming tank, A gas discharge line for discharging gas from inside the heat reforming tank to the solubilized sludge discharged from the heat reforming tank, A pressure sensor for measuring the pressure inside the heat reforming tank, A pressure control valve for opening and closing the aforementioned gas discharge line, The system includes pressure control means for adjusting the opening degree of the pressure control valve so that the measurement value of the pressure sensor becomes a target value, The thermal reforming tank is equipped with an outlet pipe for discharging the solubilized sludge, An organic waste treatment system characterized in that the gas discharge line is connected to the outlet pipe. [Claim 2] A digester for digesting organic waste from within a water treatment facility, A digested sludge circulation line that circulates a portion of the digested sludge processed in the digester back to the digester as circulating digested sludge, A thermal reforming apparatus that introduces off-site dewatered cake from the water treatment facility outside the aforementioned water treatment facility and performs thermal reforming treatment, A control device for controlling the operating conditions of the heat reforming apparatus, A thermal reforming material introduction line for introducing the thermally reformed material modified by the thermal reforming apparatus into the digester, Equipped with, In the control device, the pressure inside the heat reforming tank of the heat reforming apparatus is controlled to be maintained at or above the saturated water vapor pressure. A sludge dewatering machine that dewaters a portion of the aforementioned digested sludge to produce an in-house dewatered cake, The system includes a dewatered cake introduction line for introducing the dewatered cake from the sludge dewatering machine into the heat reforming device, The heat reforming apparatus is used to heat reform the dewatered cake from within the facility and the dewatered cake from outside the facility. The aforementioned heat reforming apparatus is A heat reforming tank for performing heat reforming treatment on sludge, A steam supply device that supplies steam to the sludge in the heat reforming tank, A gas discharge line for discharging gas from inside the heat reforming tank to the solubilized sludge discharged from the heat reforming tank, A pressure sensor for measuring the pressure inside the heat reforming tank, A pressure control valve for opening and closing the aforementioned gas discharge line, The system includes pressure control means for adjusting the opening degree of the pressure control valve so that the measurement value of the pressure sensor becomes a target value, The thermal reforming tank is equipped with an outlet pipe for discharging the solubilized sludge, An organic waste treatment system characterized in that the gas discharge line is connected to the outlet pipe. [Claim 3] The organic waste treatment system according to claim 1 or 2, characterized in that the thermal reforming conditions of the thermal reforming apparatus are 120 to 150°C, and the digestion conditions of the digester are 30 to 60°C. [Claim 4] The tank comprises an outlet pipe for discharging the solubilized sludge from the heat reforming tank, The outlet pipe has its inlet portion inserted into the inside of the heat reforming tank. The organic waste treatment system according to claim 1 or 2, characterized in that the pipe inlet is arranged to face the bottom of the heat reforming tank. [Claim 5] A liquid level sensor that measures a physical quantity correlated with the liquid level of the sludge in the heat reforming tank, A liquid level control valve that opens and closes the outlet pipe, The organic waste treatment system according to claim 4, further comprising: liquid level control means for adjusting the opening degree of the liquid level control valve so that the measurement value of the liquid level sensor becomes a target value. [Claim 6] The inner diameter of the pipe of the heat reforming tank is D, The inner diameter of the outlet pipe is d, The length from the inner wall surface of the heat reforming tank chamber at the pipe inlet to the lower end of the tip portion is X. When the upper edge angle of the tip portion in a side view is denoted as θ, X: 0 to 1 / 2D θ: 30-85 degrees d: Inner diameter 65mm ~ 1 / 2D WL: (Sludge volume) / (Tank volume) = 1 / 5 to 4 / 5 The organic waste treatment system according to claim 4, characterized in that the relationship is as follows. [Claim 7] Includes an input line L6 for introducing off-site dewatered cake 52B from an off-site water treatment facility into the heat reforming tank, The input line L6 is connected to the lower end of the heat reforming tank 11 via a mixing pot 12 to which a discharge nozzle 20 is connected. The organic waste treatment system according to claim 1 or 2, characterized in that the mixing pot 12 is equipped with a first steam pipe 15 for injecting high-temperature first steam S1 onto the off-site dewatered cake 52B.

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