JP2006071131A - Carbonizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbonizing device for giving effective carbonizing treatment while reducing heat loss by improving the utilizing efficiency of combustion heat. <P>SOLUTION: A heat exchanger 14 is provided in a heating combustion furnace 13 which supplies heat to a carbonizing furnace 12 and burns dry distilled gas E produced in the carbonizing furnace 12 following the carbonizing treatment. Heat medium B is heated and supplied via the heat exchanger 14 to a dryer 11. Thus, the utilizing efficiency of the combustion heat is improved to give effective carbonizing treatment while reducing the heat loss in the whole device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a carbonization apparatus that treats, for example, agricultural settlement wastewater treatment sludge and performs carbonization for its use.

  In general, wastewater treatment sludge generated in agricultural villages does not contain much heavy metal substances, so it is concentrated and dehydrated with a centrifugal dehydrator and then dried with a centrifugal thin film dryer, etc., and then returned to agricultural land as compost compost or compost compost. Etc. are used. However, since farmland fertilization and compost compost are unevenly used, problems such as sludge alteration during storage and odor generation occur.

  For this reason, in recent years, attempts have been made to carbonize sludge and use it as a soil improvement material. A method of carbonizing organic waste has been proposed so far (see, for example, Patent Document 1). In such a carbonization method, in order to carbonize the sludge, a pretreatment for drying the sludge with a dryer is required. In the method of Patent Document 1, the high temperature exhaust heat discharged from the deodorization furnace is used to heat the heat medium with a heat exchanger, and this heat medium is used as a heating means of the drying furnace, A drying process is performed.

However, in the above-described method, the heat exchanger is installed outside the deodorizing furnace. For this reason, heat loss is large, heat exchange efficiency is low, and heat utilization is insufficient.
JP-A-10-330760

  As described above, in the conventional techniques, it is difficult to efficiently perform the carbonization treatment because the utilization efficiency of the combustion heat is low and the heat loss is large.

  The objective of this invention is providing the carbonization apparatus which can reduce heat loss and can perform an effective carbonization process by improving the utilization efficiency of combustion heat.

  The carbonization apparatus of the present invention includes a dryer that introduces concentrated sludge and obtains dried sludge by heating with a heat medium, and a carbonization furnace that introduces the dried sludge and heats the dried sludge in a low oxygen state to perform carbonization. A heating combustion furnace that introduces auxiliary fuel, initially burns the auxiliary fuel, supplies the combustion gas to the carbonization furnace, introduces dry distillation gas generated in the carbonization furnace, and burns it as fuel; and the heating combustion furnace And a heat exchanger that heats the heat medium supplied to the dryer by the combustion heat.

  Further, in the present invention, malodorous gas generated from the dryer may be introduced into the heating combustion furnace, and the malodorous gas may be pyrolyzed at a high temperature in the heating combustion furnace.

  Moreover, in this invention, you may comprise so that the waste gas after heating a carbonization furnace may be supplied to the preheater of the dewatered sludge introduced into a dryer.

  Further, in the present invention, the dryer may have a preliminary boiler for heating the heat medium, and may be operated independently for the carbonization furnace and the heating combustion furnace.

  According to the present invention, a heat exchanger is provided in the heating and combustion furnace for supplying heat to the carbonization furnace and combusting the dry distillation gas generated by the carbonization process in the carbonization furnace, and the heat exchanger supplies the heat to the dryer. Since the heat medium is heated, the use efficiency of the combustion heat is improved, the heat loss in the entire apparatus is small, and an effective carbonization treatment can be performed.

  Hereinafter, an embodiment of a carbonization apparatus according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the overall configuration of the carbonization apparatus in this embodiment. 11 is a sludge dryer, for example, a centrifugal thin film dryer. This dryer 11 introduces concentrated sludge H having a water content of about 85% dehydrated by a decanter-type centrifugal dehydrator (not shown) provided in the preceding stage, and stretches it into a thin film on the inner wall of a cylindrical heating cylinder. The processing capacity is 30 to 40 kg / h of dry sludge G having a water content of about 50%.

  12 is a carbonization furnace which introduce | transduces the dry sludge G and heats this dry sludge G in a low oxygen state, and carbonizes. As the carbonization furnace 12, for example, a continuous indirect heating rotary kiln type is used. This type of carbonization furnace has a rotary kiln provided with a heating jacket in the outer peripheral portion, and the dried sludge G supplied into the rotary kiln is heated and carbonized by heat from the heating jacket. The treatment capacity of the carbonization furnace 12 is to carbonize dry sludge G having a water content of about 50% at 20 to 50 kg / h.

  Reference numeral 13 denotes a heating combustion furnace, which burns auxiliary fuel propane gas F and dry distillation gas E generated in the carbonization furnace 12 during carbonization of sludge and keeps it at a high temperature. The dried sludge in the rotary kiln is indirectly heated and carbonized through this heating jacket. That is, the heating and combustion furnace 13 introduces the propane gas F as an auxiliary fuel to cause initial combustion, supplies the high-temperature combustion gas D to the carbonization furnace 12 and heats it. In addition, dry distillation gas (mainly hydrocarbon) E generated along with the carbonization treatment in the carbonization furnace 12 is introduced and burned as fuel to maintain a high temperature state.

  A malodorous gas C generated from the dryer 11 is introduced into the heating and combustion furnace 13. Further, since carbonization in the carbonization furnace 12 is performed in a low oxygen state, a small amount of dioxin is generated. This dioxin is introduced into the heating combustion furnace 13 together with the dry distillation gas E. The heating and combustion furnace 13 thermally decomposes these malodorous gases and dioxins with high-temperature combustion heat and renders them harmless.

  A heat exchanger 14 is provided in the heating combustion furnace 13 and heats the heat medium B supplied to the dryer 11 with the combustion heat. Here, as the heat medium B, for example, water vapor is used. For this purpose, the heat exchanger 14 is supplied with soft water A whose tap water has been reduced in hardness by a water softener by means of a pump, and the soft water A is heated by the combustion heat of the heating combustion furnace 13 to produce a heat medium. Water vapor as B is generated. The water vapor B is supplied to a heating jacket provided on the outer peripheral portion of the centrifugal thin film dryer 11 to heat and dry the concentrated sludge stretched on the inner peripheral surface of the inner cylinder portion.

  Reference numeral 15 denotes a preheater, which introduces exhaust gas that has heated the carbonization furnace 12 as a heat source, and preheats the concentrated sludge H supplied to the centrifugal thin film dryer 11.

Next, the case where the drying treatment and carbonization are performed will be described by taking the agricultural settlement drainage treatment concentrated sludge as an example. In this case, first, the auxiliary fuel propane gas F is automatically supplied to the heating combustion furnace 13. The propane gas F is ignited and burned by a burner (not shown), and the temperature of the heating combustion furnace 13 is raised to a set temperature of 850 ° C. The combustion gas D at this time is supplied to the carbonization furnace 12 to raise the temperature in the carbonization furnace 12. Here, the supply amount of propane gas was 4 m ³ / h.

  The combustion gas D is supplied to the carbonization furnace 12 as described above, and raises the temperature of the carbonization furnace 12 to a set temperature of 800 ° C. In this case, it took 2 hours until the temperature of the carbonization furnace 12 reached 800 ° C.

  On the other hand, soft water A is supplied to the heat exchanger 14 in the heating combustion furnace 13 at a rate of 15 liters / hour, steam 175 ° C. is generated as a heat medium by the combustion heat in the heating combustion furnace 13, and the centrifugal thin film dryer 11 is supplied. The centrifugal thin film dryer 11 is supplied with concentrated sludge H (water content of about 85%) dehydrated by a decanter type centrifugal dehydrator (not shown) in the previous stage through a preheater 15 at 90 liters / hour. The centrifugal thin film dryer 11 heats and dries this concentrated sludge with a heat medium (water vapor) B to produce a dried sludge G (water content 50%) at 30 kg / h.

  The ammoniacal malodorous gas C generated during the drying treatment was passed through the heating combustion furnace 13 and thermally decomposed at a high temperature of 850 ° C. to deodorize it.

  While continuing the production of the dried sludge G, the produced dried sludge G was supplied to the carbonization furnace 12 whose temperature was increased to a set temperature of 800 ° C., and carbonization was started.

  Carbonization conditions are as follows.

・ Dry sludge supply amount: 30 (kg / h)
-Carbonization temperature: 800 (° C)
Carbonization time: 20 (minutes)
・ Rotary kiln rotation speed: 5 (rpm)
After 10 minutes from the start of supplying the dried sludge G to the carbonization furnace 12, dry distillation gas E was generated from the dried sludge. The dry distillation gas E is mainly composed of hydrocarbons, and is supplied to the combustion heating furnace 12 to be burned as fuel. The dioxins generated in the carbonization furnace 12 are introduced into the heating combustion furnace 13 together with the dry distillation gas and thermally decomposed at a high temperature (850 ° C.) in the heating combustion furnace 13.

  Thus, dry sludge was continuously supplied into the carbonization furnace 12 for 5 hours, and 150 kg of dry sludge was carbonized to produce 60 kg of carbide.

  During the carbonization process (5 hours), 450 liters of concentrated sludge is supplied to the centrifugal thin film dryer 11, and 150 kg of dried sludge is continuously produced. The produced dried sludge G is similarly supplied to the carbonization furnace 12 and carbonized.

In this manner, the heating combustion furnace 13 is initially burned with the auxiliary fuel F, the combustion gas D is supplied to the carbonization furnace 12 and heated, the sludge is carbonized, and the dry distillation gas generated with the carbonization treatment is heated. It introduces into the combustion furnace 13 and burns it as fuel. Moreover, it can heat efficiently by providing the heat exchanger 14 in the heating combustion furnace 13, and heating directly with the combustion heat. From these things, the utilization efficiency of the combustion heat in the whole apparatus can be improved, heat loss can be reduced, and an effective carbonization treatment can be performed.The present invention is not limited to the above configuration, Various modifications may be made. For example, although not shown, the dryer 11 may be provided with a preliminary boiler for heating the heat medium B so that the carbonization furnace 12 and the heating combustion furnace 13 can be operated independently. In this case, a kerosene boiler is used as a spare boiler, and water vapor as a heat medium is heated. That is, the kerosene boiler is burned to generate 170 ° C. water vapor and supplied to the centrifugal thin film dryer 11. Concentrated sludge H (water content 85%) was supplied to the centrifugal thin film dryer 11 at 90 liter / hour, and dry sludge G (water content 50%) was produced at 30 kg / h.

In this way, 450 liters of concentrated sludge was supplied to the centrifugal thin film dryer 11 continuously for 5 hours to produce 150 kg of dried sludge. The amount of kerosene used for this drying treatment was 60 liters. 150 kg of the produced sludge was supplied to the carbonization furnace 12 in the same manner as described above, and carbonized under the same conditions to produce 60 kg of carbide.
As described above, when the dryer 11 is provided with a spare boiler so that it can be operated independently, even if the carbonization furnace 12 is not operated for inspection or the like (in this case, the heating combustion furnace 13 is not also operated), the dryer 11 is made uniquely The dried sludge G can be manufactured in advance.

It is a whole lineblock diagram showing one embodiment of a carbonization device by the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Dryer 12 Carbonization furnace 13 Heating combustion apparatus 14 Heat exchanger 15 Preheater A Soft water B Heat medium (steam)
C Odor gas D Combustion gas E Distillation gas F Auxiliary fuel G Dry sludge H Concentrated sludge

Claims (4)

A dryer that introduces concentrated sludge and obtains dried sludge by heating with a heat medium;
A carbonization furnace for introducing the dry sludge and heating the dry sludge in a low oxygen state to perform carbonization;
A heating combustion furnace that introduces auxiliary fuel, initially burns the auxiliary fuel, supplies the combustion gas to the carbonization furnace, introduces dry distillation gas generated in the carbonization furnace, and burns it as fuel;
A heat exchanger that is provided in the heating combustion furnace and heats the heat medium supplied to the dryer by the combustion heat;
A carbonization apparatus comprising:   The carbonization apparatus according to claim 1, wherein malodorous gas generated from the dryer is introduced into a heating combustion furnace, and the malodorous gas is thermally decomposed.   The carbonization apparatus according to claim 1, wherein the exhaust gas after heating the carbonization furnace is supplied to a preheater for concentrated sludge introduced into a dryer.   The carbonization apparatus according to claim 1, wherein the dryer has a preliminary boiler for heating the heat medium, and can be operated independently for the carbonization furnace and the heating combustion furnace.

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