JP2006007139A - System and method for treating material to be treated - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for treating a material to be treated capable of significantly reducing a running cost of the whole system by producing methanol which makes a large proportion of the running cost required to treat in the treating process and also efficiently utilizing methanol, and a method for treating the material to be treated. <P>SOLUTION: Methanol produced by a methanol production apparatus 3 can be used for either of denitrification treatment of sewage sludge and an electric generator 4, and gas yielded by a gasifying apparatus 2 can also be used for the electric generator 4. A control mechanism is provided so as to sense methanol required to carry out denitrification treatment and operate the electric generator 4, and on the basis of the sensing result, select/feed methanol produced by the methanol production apparatus 3 to the denitrification treatment or the electric generator 4 each by a required amount. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an object processing system and an object processing method, and more specifically, a gasification apparatus for gasifying an object to be processed, and a methanol production apparatus for producing methanol from a gas obtained by the gasification apparatus. The present invention relates to a workpiece processing system and a workpiece processing method.

  Sludge generated from sewage treatment plants and human waste treatment plants has many organic components and few harmful components such as heavy metals. Therefore, after being dehydrated or dried, they are buried in landfills or incinerated. However, since there are many organic components, it contains high-concentration nitrogen, and denitrification treatment is performed because of the need to prevent eutrophication to protect the environment of the disposal site. In order to activate the denitrifying bacteria in the denitrification treatment, it is necessary to add methanol or the like as a carbon source (usually, it is necessary to add about three times as much carbon as the nitrogen contained), but methanol is never cheap. Therefore, the cost of methanol occupying the running cost necessary for the sludge disposal is large, leading to an increase in running cost.

Therefore, in order to reduce the running cost for disposal of human waste sludge as much as possible, the solid matter obtained by the sludge treatment process is gasified or gasified and combusted, and the obtained gas is recovered as electric power or thermal energy. And the method of utilizing this for sludge processing is proposed (for example, patent documents 1).
JP-A-9-150143

  However, the above-mentioned prior art only uses the solid matter generated in the sludge disposal process as an energy source, and does not reduce the amount of expensive methanol used, so it is not sufficient as a reduction in running cost in sludge treatment. .

  Therefore, in view of the above-mentioned problems of the prior art, the object of the present invention is to treat methanol that accounts for a large proportion of the running cost required for treatment when methanol is used for treatment of an object to be treated such as sewage sludge. An object of the present invention is to provide a processing object processing system and a processing object processing method that can efficiently reduce the running cost of the entire system by efficiently using this methanol when manufactured in the process.

  The above object can be achieved by the invention described in the claims. That is, the characteristic configuration of the sludge treatment system according to the present invention includes a gasification device that gasifies an object to be treated, and a methanol production device that produces methanol from the gas obtained by the gasification device, The methanol produced by the methanol production apparatus can be used for both the denitrification treatment of the object to be processed and the power generation apparatus, and the gas obtained by the gasification apparatus can also be used for the power generation apparatus. In the treatment system, the methanol required for the denitrification treatment and the methanol required for the power generation device are detected, and the methanol produced by the methanol production device based on the detection result is supplied to the denitrification treatment or the power generation device. In other words, a control mechanism is provided to select and feed only the necessary amount.

  According to this configuration, when it is necessary to use methanol for the treatment of the object to be treated, it is possible to supply methanol at a low cost by producing methanol having a large proportion of the running cost from the object to be treated. By controlling to select and deliver power and power generation, it is possible to efficiently use methanol in the system.

  As a result, when methanol is used for the treatment of an object to be treated such as sewage sludge, when methanol having a large proportion of the running cost required for the treatment is produced in the treatment process, this methanol is efficiently used, It was possible to provide a workpiece processing system that can significantly reduce the overall running cost.

  It is preferable that the refiner | purifier which refine | purifies the gas obtained by the said gasifier is provided in the upstream of the said methanol production apparatus, and produces | generates methanol from the refined gas.

  According to this configuration, since harmful components are removed from the gas necessary for the production of methanol, high-purity methanol can be efficiently produced, and the utilization efficiency in the subsequent steps is increased.

  It is preferable that unreacted gas generated in the methanol production apparatus can be supplied to the power generation apparatus.

  According to this configuration, the unreacted gas has a large calorific value, can be effectively used as a fuel for the power generation apparatus, and can greatly contribute to a reduction in running cost of the entire system.

  Moreover, the characteristic structure of the to-be-processed object processing method which concerns on this invention gasifies a to-be-processed object with a gasifier, and sends this gas to a methanol manufacturing apparatus, manufactures methanol, This methanol is said to-be-processed object In the denitrification treatment and the power generation apparatus, and in the treatment method of making the gas obtained by the gasification apparatus usable also in the power generation apparatus, methanol required for the denitrification treatment, The methanol required for the power generation device is detected, and based on the detection result, the methanol produced by the methanol production device is controlled to be denitrified or selected and supplied to the power generation device in a necessary amount. There is.

  According to this configuration, when methanol is used for the treatment of an object to be treated such as sewage sludge, when methanol having a large proportion of the running cost required for the treatment is produced in the treatment process, the methanol is efficiently used. Thus, it is possible to provide an object processing method that can significantly reduce the running cost of the entire system.

  It is preferable to purify the gas obtained by the gasifier and supply the purified gas to the methanol production apparatus to produce methanol.

  According to this configuration, high-purity methanol can be efficiently produced, and utilization efficiency in the subsequent steps is increased.

  It is preferable that unreacted gas generated in the methanol production apparatus can be supplied to the power generation apparatus.

  This configuration can greatly contribute to the reduction of the running cost of the entire system.

  It is preferable that the object to be treated is heated to 700 to 900 ° C. in the gasifier and gasified, and a gasifying agent is supplied to the gasifier.

  According to this configuration, the operation of the gasifier can be performed more stably.

  It is preferable that the methanol production in the methanol production apparatus is performed at a temperature of 200 to 240 ° C. and a pressure of 2 to 4 MPa by a one-pass process without passing through a circulation process.

  This configuration not only consumes less energy than the conventional technology, but also avoids energy loss during circulation and reduces the number of compressors arranged compared to the conventional circulation type. This can reduce the equipment cost of the entire system.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a sludge treatment system according to the present embodiment.

  This sludge treatment system is a circulating fluidized bed gas, which is a kind of gasifier, for treating sludge generated from a sewage treatment plant or human waste treatment plant 1 (hereinafter also referred to as a sewage treatment plant, etc.). Then, the sludge is heated to about 700 to 900 ° C. and gasified, and methanol is produced by the methanol production apparatus 3 using the obtained gas. The produced methanol is supplied to the sewage treatment plant 1 or the like. It is sent and used as a carbon source for denitrification treatment. Furthermore, the gas obtained by the circulating fluidized bed gasification furnace 2 is supplied to the power generation device 4 which is an external facility and is also used for recovery as electric power.

  Hereinafter, the configuration of each device will be described in more detail. It is preferable that the sludge generated from the sewage treatment plant 1 is dehydrated and dried so as to be reduced in volume and volume before being fed to the circulating fluidized bed gasification furnace 2. Various methods can be adopted for dehydration or drying, and the method is not particularly limited. As the drying device, for example, various types such as a direct heating type, an indirect heating type, a type using a heater, and a type using steam can be used.

  The dried and dehydrated sludge is put into the circulating fluidized bed gasification furnace 2 and heated to be gasified. This circulating fluidized bed gasification furnace 2 is convenient because it is easy to control the gasification temperature and enables stable operation. In the circulating fluidized bed gasification furnace 2, a fluid medium such as silica sand is flowed by a fluid such as air, and the sludge is heated and gasified. As described above, the operation temperature in the furnace is about 700 to 900 ° C., but it is preferable to add a gasifying agent such as oxygen and steam in addition to the fuel as necessary. This is because a more stable operation can be performed by using a gasifying agent.

  From the heated and partially burned sewage sludge, a gas containing carbon monoxide, hydrogen, hydrocarbons and the like is generated. A purification device for purifying the gas thus obtained is connected to the downstream side of the circulating fluidized bed gasification furnace 2 to remove harmful components such as ash, tar, acidic components and alkaline components in the gas. Preferably, methanol is produced from the purified gas. In this case, the ash is removed using a ceramic filter or a bag filter, the tar is removed by a removing means using a catalyst, and other harmful components are removed using a gas cleaning system or the like.

  The amount of gas generated by the circulating fluidized bed gasification furnace 2 is respectively required for the methanol production apparatus 3 and the power generation apparatus 4 via a switching valve, an on-off valve (not shown) provided in the middle of supply, and the like. Only be selected and sent. This selection / feeding can be performed by switching the switching valve or adjusting the opening / closing degree of the opening / closing valve using a control device (not shown). That is, when power generation is prioritized, most of the generated gas is supplied to the power generation device 4, but surplus gas is supplied to the methanol production device 3 for methanol production. In the case of giving priority to the production of methanol, the gas is supplied to the methanol production apparatus 3 in an amount capable of generating methanol necessary as a carbon source for denitrification, and then the remaining gas and unreacted in the methanol production apparatus 3 Gas is sent to the power generator 4.

  The methanol production apparatus 3 is composed of a reaction tower or the like for making the gas into a pressurization / heating condition necessary for methanol production, and the gas fed here is subjected to the pressurization and temperature conditions necessary for methanol synthesis. Furthermore, it is used for methanol synthesis by interposing a catalyst as required. As the methanol production apparatus 3, a conventional apparatus can be used. In particular, it is preferable to synthesize methanol by a one-pass process at a temperature of 200 to 240 ° C. and a pressure of 2 to 4 MPa without passing through a circulation process. Under these conditions, the temperature and pressure are lower than in the conventional technology, so not only less energy is consumed, but also energy loss during circulation is avoided compared to the circulation type as in the conventional technology. In addition, the number of compressors can be reduced and the equipment cost of the entire system can be reduced.

  On the other hand, the power generation device 4 includes a gas turbine and a steam turbine or the like (not shown) connected thereto, and high power generation efficiency can be achieved by using these together. It is preferable that unreacted gas in the methanol production apparatus 3 is also supplied to the power generation apparatus 4 and, if necessary, auxiliary fuel such as methanol produced in the methanol production apparatus 3 or city gas is supplied. However, as the power generation device, a gas turbine alone or a gas engine may be used, and these can be selected as appropriate from the amount of sludge treated and the characteristics.

  Furthermore, in this embodiment, in order to effectively utilize the methanol produced by the methanol production apparatus 3 in the system, a control mechanism (not shown) for controlling the amount of feeding is provided. In other words, when power generation is prioritized, the amount of power generation is insufficient, the carbon source for denitrifying bacteria is detected to be sufficient, and if the need to supply the carbon source is low, the degree of power generation shortage Accordingly, the generated methanol is controlled to be mainly fed to the power generation device 4.

  When the amount of power generation is sufficient and the carbon source of denitrifying bacteria is insufficient, the methanol is controlled to be supplied mainly to a denitrification tank such as a sewage treatment plant. When both the power generation amount and the carbon source are insufficient, the use of methanol as a carbon source reduces the running cost rather than the use of methanol as a fuel, so control is mainly performed to supply to a sewage treatment plant or the like. In addition, if both the amount of power generation and the carbon source are sufficiently secured, methanol may be temporarily stored and stored in a separate storage tank until use, or other chemical factories may be used as raw materials. You may use for the use. The necessary amount of the carbon source can be easily calculated by measuring the nitrogen concentration in the treated water, and the amount of power generation can be easily detected by using a power meter or the like.

  By providing the control mechanism in this way, the efficiency of the entire sludge treatment system can be improved, the amount of expensive methanol used can be made appropriate, and the treatment cost can be reduced.

  The electric power obtained by the power generation device 4 is effectively used as a driving power source for a sewage treatment plant or the like, as well as a driving power for the present sludge treatment system, or as a power sale or others. Further, a heat source generated from a gas turbine or a steam turbine may also be used in addition to power generation.

About 10 t-wet / day of sewage sludge generated from a sewage treatment plant with a sewage treatment amount of about 10,000 t / day, methanol was produced according to the above-described treatment steps. The used sewage sludge has a water content of about 80%, an SS (solid suspended matter) concentration of about 0.2 kg / m ³ , and a nitrogen content of about 15 ppm. The amount of methanol required as a carbon source for treating this sludge is: About 450 kg / day.

In this example, as shown by the following formula 1, the methanol conversion rate is about 50%, and oxygen is used as a gasifying agent in the circulating fluidized bed gasification furnace (processing capacity 30 t / day) at about 27 Nm ³ / hour. While being fed, the sewage sludge was heated to about 850 ° C. for gasification, and the generated gas was fed at about 260 Nm ³ / hour to a methanol production apparatus to obtain about 430 kg / day of methanol. At this time, the reaction tower of the methanol production apparatus was synthesized under conditions of about 4 MPa and about 220 ° C.

Thus, the amount of methanol obtained corresponded to nearly the total amount of methanol required for sludge treatment (95% or more). Further, unreacted gas during the methanol production process contains carbon monoxide, hydrogen, etc., and these have a calorific value of about 6-7 MJ / Nm ³ , By supplying it to the device 4, it could be used as a drive power source for this sludge treatment system or as a power sale.
[Formula 1]
Amount of methanol produced (kmol) / Amount of carbon monoxide in the gas after gasification gas purification (kmol) = 50%
[Another embodiment]
(1) In the above embodiment, sewage sludge has been described as an example of the object to be treated. However, as the object to be applied to the present invention, if methanol treatment is required as an advanced treatment during the treatment, The sludge is not limited to sewage sludge, and may be general sludge or other organic waste.
(2) In the above embodiment, a circulating fluidized bed gasification furnace has been described as an example of a gasifier, but other fluidized bed furnaces can be used as long as the product gas in a temperature range equivalent to this can be discharged. A gasifier may be used.

The schematic block diagram of the to-be-processed object processing system which concerns on one Embodiment of this invention.

Explanation of symbols

2 Gasifier 3 Methanol production device 4 Power generator

Claims (8)

A gasifier for gasifying the object to be processed; and a methanol manufacturing apparatus for manufacturing methanol from the gas obtained by the gasifier, wherein the methanol manufactured by the methanol manufacturing apparatus is converted into the object to be processed. This is necessary for the denitrification process in the object treatment system that makes it possible to use both the denitrification process and the power generation apparatus of the gas and the gas obtained by the gasification apparatus also for the power generation apparatus. Methanol and methanol required for the power generation device are detected, and based on the detection result, methanol produced by the methanol production device is selected and supplied to the denitrification process or to the power generation device, respectively. A workpiece processing system, characterized in that a control mechanism is provided. The to-be-processed object processing system of Claim 1 with which the refiner | purifier which refine | purifies the gas obtained by the said gasifier is provided in the upstream of the said methanol production apparatus, and produces | generates methanol from the refined gas. The to-be-processed object processing system of Claim 1 or 2 which can supply the unreacted gas which generate | occur | produced in the said methanol manufacturing apparatus to the said electric power generation apparatus. A gasification apparatus gasifies the object to be processed, and this gas is supplied to a methanol production apparatus to produce methanol. The methanol can be used for both denitrification treatment of the object to be processed and a power generation apparatus. In the method for treating an object to be used, the gas obtained by the gasifier can also be used in the power generation device, and the methanol required for the denitrification treatment and the methanol required for the power generation device are detected. A processing method for an object to be processed, comprising: controlling the methanol produced by the methanol production apparatus based on the detection result so as to select and supply a required amount of methanol to a denitrification process or a power generation apparatus. The to-be-processed object processing method of Claim 4 which refine | purifies the gas obtained by the said gasifier, and supplies the refined gas to the said methanol manufacturing apparatus, and produces | generates methanol. The processing method of the to-be-processed object of Claim 4 or 5 which can supply the unreacted gas which generate | occur | produced in the said methanol manufacturing apparatus to the said power generation apparatus. The object to be treated according to any one of claims 4 to 6, wherein the object to be treated is heated to 700 to 900 ° C in the gasifier and gasified, and a gasifying agent is supplied to the gasifier. Processed material treatment method. The object treatment according to any one of claims 4 to 7, wherein the methanol production in the methanol production apparatus is performed at a temperature of 200 to 240 ° C and a pressure of 2 to 4 MPa in a one-pass process without passing through a circulation process. Method.

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