JP2015208716A - Sludge drying installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge drying installation which reduces the temperature variation of dried exhaust gas and allows stabilization of the treatment capacity of the whole system.SOLUTION: A sludge drying installation 1 includes a disintegrator 31 which dries sludge with circulated air and disintegrates the sludge and sludge circulation paths 82 to 85 for connecting the upstream and downstream of the disintegrator together and also is provided with a heat exchange line 88A which supplies circulated air before temperature raising to the heat exchanger 50 and returns the circulated air after temperature raising to the sludge circulation path and a bypass line 88B which returns the circulated air to the sludge circulation path without passing through the heat exchanger 50. The sludge drying installation 1 is provided with control means of controlling the supply amount of the circulated air supplied to the heat exchange line 88A, and the control means controls the supply amount of the circulated air supplied to the heat exchange line 88A on the basis of the temperature of the inlet of the disintegrator.

Description

  The present invention relates to a sludge drying facility that dries sludge with a high-temperature drying gas, and more particularly to a sludge drying facility that can reduce temperature fluctuations of dry exhaust gas and stabilize the processing capacity of the entire system.

  Conventionally, it is known that sludge waste (simply referred to as “sludge”) such as livestock manure and sewage sludge is dried with a drier, and the resulting dry solid is used as fuel.

  For example, in Patent Document 1, sludge waste is transported together with a drying gas, pulverized by a pulverizer, then solid-gas separated by a solid-gas separation device, and part of the separated gas is again dried. A treatment facility that is circulated as a gas is disclosed. Further, in this document, for example, about 300 ° C. is exemplified as the temperature of the hot air for drying (mixed gas of combustion exhaust gas and circulating gas).

JP 2000-65476 A

  As described above, in equipment for circulating wet waste by circulating a high-temperature gas, it is important to control the temperature of the dry exhaust gas from the viewpoint of stabilizing the processing capacity of the entire system.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a sludge drying facility that can reduce the temperature fluctuation of the dry exhaust gas and stabilize the processing capacity of the entire system. There is.

  The sludge drying equipment of one form of the present invention for solving the above-mentioned problems is as follows.

Sludge supply source,
A heat exchanger that raises the temperature of the circulating air;
While drying the sludge with the circulating air, a crusher for crushing the sludge,
A sludge circulation path connecting the upstream and downstream of the crusher;
Solid-gas separation means provided on the downstream side of the crusher in the sludge circulation path,
The sludge circulation path is provided separately, and includes a branching means for discharging part of the sludge after drying from the downstream of the solid-gas separation means,
A mixer that is provided on the downstream side of the solid-gas separation means in the sludge circulation path, mixes and discharges sludge after drying and sludge before drying supplied from the sludge supply source;
The sludge circulation path is connected to the heat exchanger, and has a pipe connection portion for supplying the circulating air to the downstream side of the mixer,
A heat exchange line connected to the sludge circulation path, supplying the circulating air before the temperature rise to the heat exchanger, and returning the circulation air after the temperature rise to the sludge circulation path;
A bypass line provided in parallel with the heat exchange line and returning the circulating air to the sludge circulation path without passing through the heat exchanger;
A temperature measuring means provided between the pipe connection portion and the heat exchanger, for measuring a crusher inlet temperature;
Control means for controlling the amount of circulating air supplied to the heat exchange line,
The crusher is the sludge circulation path and is provided on the downstream side of the pipe connection part,
The said control means controls the supply amount of the circulating air supplied to the said heat exchange line based on the said crusher inlet temperature. The sludge drying equipment characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the sludge drying equipment which can reduce the temperature fluctuation | variation of dry waste gas and can stabilize the processing capacity of the whole system can be provided.

It is a figure which shows typically the structure of the sludge drying installation by one form of this invention. It is a flowchart which shows an example of the processing flow in the installation of FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, expressions such as “upstream” and “downstream” may be used on the basis of sludge waste and gas flow direction.

  The sludge drying facility 1 of FIG. 1 includes a receiving hopper 10 as a sludge supply source, a mixer 15 disposed on the downstream side thereof, a pulverizer 31 for pulverizing sludge waste discharged from the mixer 15, Cyclones 35 and 36 as solid-gas separation means arranged on the downstream side, and a heat exchanger 50 for raising the temperature of circulating dry exhaust gas (circulated air) are provided. In this embodiment, a cement production facility 120 is also provided, and waste heat from the cement production facility 120 is supplied to the heat exchanger 50.

  The receiving hopper 10 is a part that receives sludge waste before drying. The sludge waste is not limited, but may be livestock manure, sewage sludge or the like. The sludge waste supplied to the receiving hopper 10 is sent downstream by the supply pump 11 and the like. Specifically, in this example, the outlet of the supply pump 11 and the mixer 15 are connected by a conveyance path 81, and sludge waste is sent to the mixer 15 via the conveyance path 81.

  The mixer 15 is an apparatus that mixes the sent sludge waste before drying and the sludge waste after drying (detailed later). The sludge waste mixed by the mixer 15 is sent into a sludge circulation path (described later in detail).

  Here, the sludge circulation path of the present embodiment will be described. In this example, a circulation line 82 that connects the mixer 15 and the crusher 31, a circulation line 83 that connects the crusher 31 and the cyclones 35 and 36, and a cyclone. Circulation lines 84 and 85 connecting the solid outlets 35 and 36 and the mixer 15 are provided. Roughly speaking, sludge waste is pulverized by the crusher 31 while being transported in the circulation path (82 to 85) by a drying gas described later, and then solid-gas separated by the cyclones 35 and 36. The dried solids separated by the above are discharged from the cyclone outlet side, sorted by the sorting means 39, and sent to the cement production facility 120 side.

  In the present embodiment, in addition to the above-described sludge circulation path (partially common), a circulation path for drying gas is also provided. Specifically, (a) a gas line 87 that conveys the outlet gas from the gas outlet side of the cyclones 35 and 36 to the downstream side, and (b1) heat that branches from the middle of the gas line 87 and travels toward the heat exchanger 50. An exchange line 88A, (b2) a bypass line 88B that bypasses the heat exchanger 50, and (c) a return gas line 89 that returns the drying gas from the heat exchanger 50 to the sludge circulation path (82 to 85) are provided. It has been.

  The return gas line 89 extends from the heat exchanger outlet and is connected to the end of the return gas line 89 in the sludge circulation line 82 (connecting portion P1). As a result, the high-temperature drying gas is blown into the circulation line 82, and the sludge is conveyed by gas. A thermometer 22 that measures the internal gas temperature may be provided on the upstream side of the connection portion P <b> 1 of the return gas line 89. A flow meter (not shown) for measuring the gas flow rate may be provided. The thermometer 22 may be of any type as long as it can measure the gas temperature. For example, the thermometer 22 may have an analog display unit or a digital display unit.

  The crusher 31 finely grinds the sludge waste that has been sent. The crusher 31 is not particularly limited, and for example, a crusher 31 used in Japanese Patent Laid-Open No. 2000-65476 may be used. The sludge waste discharged from the crusher 31 is sent to the cyclones 35 and 36 via the circulation line 83.

  The cyclones 35 and 36 perform solid-gas separation. In this example, two cyclones are connected in parallel as an example. A part of the outlet gas of the cyclones 35 and 36 is circulated and used as a drying gas, and the separated dry solid is sent to the cement production facility 120 side or to the mixer 15 side (that is, in the sludge circulation path). Returned. A conventionally known rotary valve RV may be disposed downstream of each of the cyclones 35 and 36.

  Next, the configuration of the heat exchanger 50 and the surrounding gas circulation path will be described in detail.

  The heat exchanger 50 serves to raise the temperature of the drying gas using an external heat source. As an example, in this example, the exhaust gas from the cement manufacturing facility 120 is used.

  In the present embodiment, as described above, the heat exchange line 88A and the bypass line 88B are branched from the middle of the gas line 87 (branch portion P2), whereby the line to the heat exchanger 50, A line that bypasses the heat exchanger 50 and connects to the return gas line 89 is formed. As a result, the gas passing through the heat exchanger 50 is heated, and the bypass gas is not heated.

  Although not particularly limited, on the upstream side of the branch portion P2, the air flow meter 21 for measuring the gas flow rate, the valve V3 for opening and closing the flow path, and the gas are sent to the downstream side on the gas line 87. A drying fan B1 or the like may be provided.

  The heat exchange line 88A and the bypass line 88B are also provided with flow path opening and closing valves V1 and V2, respectively. By operating these valves V1 and V2, the flow path opening and closing can be adjusted. It can be done.

  The valves V1 and V2 may be manually operated (opening / closing and / or opening degree adjustment) by an operator.

  Another embodiment includes a drive mechanism (not shown) that opens and closes and / or adjusts the opening of the valves V1 and V2, and a control circuit (for example, a computer unit) that automatically controls the operation of the drive mechanism. The control circuit may be configured to control the operation of the drive mechanism by making a predetermined determination.

As the cement manufacturing facility 120, various types of conventionally known ones can be used, and the cement manufacturing facility 120 is not limited to a specific structure. For example, as disclosed in Japanese Patent No. 4445147,
-A mixing unit for mixing the sludge cake and a part of the dried powder dried by the air dryer described below,
-A crusher for crushing the mixed powder from this mixing section together with a hot air flow;
-A substantially vertical drying duct for air-drying the crushed powder;
-A dust collector connected to the upper end of the drying duct;
-A dryer exhaust duct connected to the top of the dust collector;
An air dryer having a dry powder supply tank with a dry powder supply device connected to the lower part of the dust collector via a discharger;
A suspension preheater comprising a multi-stage cyclone;
-A calcining furnace connected to the lowermost cyclone of the suspension preheater;
-A rotary kiln connected via an inlet hood to the calciner and the lowermost cyclone;
A cement firing device having a cooler coupled to the outlet of the rotary kiln;
A cement manufacturing facility comprising

  Referring to FIG. 1 again, in this example, an elevator 63, a raw material tank 65, a rotary valve RV, a once-through feeder 67, a roots blower 69, and the like constituting a receiving portion for raw materials and the like are provided as the cement manufacturing facility 120. As a result, the dry raw material is supplied to the lower part of the suspension preheater 121 and combusted in the rotary kiln 125. Waste heat of the rotary kiln 125 is sent to the cyclones 135 and 136 through the gas line 91 and further supplied to the heat exchanger 50 through the gas line 93.

  The outlet gas exiting from the heat exchanger 50 may be configured to be returned to the cement production facility 120 via the gas line 94. In this example, a valve V5 and a hot air fan B3 are provided on the gas line 94. Further, the gas may be configured to be sent to the combustion gas flow path 127 of the cement manufacturing facility 120 through the gas line 97 branched from the middle of the heat exchange line 88A. The solids separated by the cyclones 135 and 136 may be returned to the cement production facility 120 via the conveyance path 92 using the screw conveyor 137 and the roots blower 138.

  The basic operation of the sludge drying apparatus 1 of the present embodiment configured as described above will be described below.

  First, the sludge waste to be treated is supplied to the receiving hopper 10, and is sent to the mixer 15 via the conveyance path 81 by the supply pump 11. The sludge waste mixed here is then discharged from the outlet of the mixer 15 to the sludge circulation line 82. When the sludge waste passes through the rotary valve RV and reaches the connection part P1, the drying gas from the heat exchanger 50 side is blown in here, so the sludge waste is then gas transported by the drying gas. And sent to the crusher 31.

  Next, in the crusher 31, the sludge waste is finely crushed, gas transported further downstream, and sent to the cyclones 35, 36 for solid-gas separation. The separated solid is sent to the cement production facility 120 side or returned to the mixer 15. In addition, when sending a solid substance to the cement manufacturing equipment 120 side, the quantity may be measured, for example with the flowmeter 61, and the rotary valve RV may be utilized.

  The outlet gas of both cyclones 35 and 36 is sent to the downstream heat exchanger 50 side through the gas line 87. The drying gas passing through the gas line 87 may be such that at least one of air volume and temperature is measured. In this state, the valve V3 is open, and one or both of the valves V1 and V2 are open.

  About adjustment of the gas flow rate which passes the heat exchanger 50, it can control according to a flowchart as shown in FIG. 2 as an example.

  First, after the operation of this facility is started (one example), the crusher inlet temperature is set in step S1. The “cracker inlet temperature” refers to the temperature of the drying gas upstream of the crusher 31 (particularly, as an example, upstream of the connecting portion P1). As an example, this set value of the crusher inlet temperature may be in the range of about 150 ° C to 350 ° C. Note that such setting value determination (step S1) may be performed in advance before the start of the sludge waste drying operation, but before the start.

  Next, in step S2, the crusher inlet temperature is measured. This step may be performed, for example, by the operator looking at the thermometer 22. Alternatively, a control circuit such as a computer may be performed by obtaining information of the detected value from the thermometer 22.

  Next, in step S3, the set temperature is compared with the measured value, and it is determined whether or not the set temperature is higher than the measured value. When the set temperature is higher than the measured value (in the case of Yes), it means that the temperature of the drying gas in the circulation path is low, so in step S4, the temperature raising action by the heat exchanger 50 is increased. The flow path opening is adjusted. Specifically, the valve is operated and (a) the opening degree of the heat exchange line 88A is raised and the opening degree of the bypass line 88B is lowered, or (b) the heat exchange line 88A is completely opened and only the bypass line 88B is opened. Try to block it. By doing in this way, since the temperature raising effect | action of gas increases, the temperature of the gas for drying can be raised gradually.

  On the other hand, in step S3, when the set temperature is equal to or lower than the measured value (in the case of No), it means that the temperature of the drying gas in the circulation path is high, so in step S5, the gas temperature rising action is reduced. Thus, contrary to the above, the flow path opening may be adjusted. Thereby, the temperature of the drying gas sent to the crusher 31 can be gradually reduced.

  The above steps may also be performed by an operator, or a driving mechanism (not shown) may automatically open and close a valve based on an operation signal from a control circuit. .

  In conventional sludge drying equipment, it is common to simply control the air volume balance between the line that is circulated to the heat exchanger and the line that is not circulated so that the temperature of the dry exhaust gas to be controlled is, for example, about 115 ° C. It was. In particular, when waste heat from a cement production facility is used as a heat source for a heat exchanger, the temperature of the waste heat is about ± 30 ° C. with respect to 400 ° C. as an example, depending on the operation status of the cement production process. It may fluctuate. Further, the sludge waste itself also has a moisture content that varies within a range of 80% to 85%, for example. Therefore, even if the temperature of the dry exhaust gas between the cyclones 35 and 36 and the drying fan B1 is controlled to a predetermined temperature, a temperature fluctuation of about ± 5 ° C. occurs.

  On the other hand, according to the configuration of the present embodiment, the circulation air flow to the heat exchanger 50 and the bypass air flow are controlled with a point downstream from the point where the return gas line 89 and the bypass line 88B merge. Therefore, it is possible to stabilize the temperature of the dry exhaust gas. As a result, the water content of the product (dried sludge) is stabilized, fluctuations in the processing capacity of the drying equipment are reduced, and the occurrence of troubles such as crusher overload is suppressed.

  In addition, by introducing cascade control that automatically follows deviations in dry exhaust gas and changes in the amount of sludge waste to be introduced, the temperature fluctuations in the dry exhaust gas can be further improved. Can be small.

  As mentioned above, although one form of this invention was demonstrated along the specific example, this invention is not necessarily limited to said specific structure and procedure. Each part apparatus etc. of the sludge drying equipment 1 can be suitably changed in the range which does not deviate from the meaning of this invention.

  In the present invention, for example, “apparatus” and “means” are not necessarily limited to those physically configured as one. A plurality of devices or the like may be combined to constitute an “device” that exhibits a predetermined function.

  In the above embodiment, the sludge waste and drying gas paths have been described using terms such as “conveyance path” and “line”, but the routing of these “conveyance path” and “line” is also changed as appropriate. Is possible. Further, the number and arrangement position of valves and rotary valves that open and close the flow path can be changed as appropriate.

(Appendix)
This application discloses the following inventions:
1. Sludge supply source (10);
A heat exchanger (50) for raising the temperature of the circulating air;
A crusher (31) for drying sludge with the circulating air and crushing the sludge,
A sludge circulation path (82 to 85) connecting the upstream and downstream of the crusher;
Solid-gas separation means (35, 36) provided on the downstream side of the crusher in the sludge circulation path;
A branching means (39) provided separately from the sludge circulation path and for partially discharging the sludge after drying from the downstream of the solid-gas separation means,
Mixing which is the said sludge circulation path (82-85), is provided in the downstream of the said solid-gas separation means, mixes sludge after drying, and sludge before drying supplied from the said sludge supply source, and discharges Machine (15),
A pipe connection part (P1) that is the sludge circulation path, is connected to the heat exchanger, and supplies the circulating air to the downstream side of the mixer;
A heat exchange line (88A) connected to the sludge circulation path, supplying the circulating air before temperature rise to the heat exchanger, and returning the circulating air after temperature rise to the sludge circulation path;
A bypass line (88B) provided in parallel with the heat exchange line and returning the circulating air to the sludge circulation path without passing through the heat exchanger;
A temperature measuring means (22) provided between the pipe connection part (P1) and the heat exchanger (50) for measuring a crusher inlet temperature;
Control means (V1, V2) for controlling the supply amount of circulating air supplied to the heat exchange line,
The crusher (31) is the sludge circulation path and is provided on the downstream side of the pipe connection part (P1),
The control means (V1, V2) controls the supply amount of circulating air supplied to the heat exchange line (88A) based on the inlet temperature of the crusher.

  According to such a configuration, the control accuracy is improved by controlling the supply amount of the circulating air supplied to the heat exchange line based on the crusher inlet temperature, which is the temperature immediately before the circulating air and sludge are mixed. Can do.

2. The sludge drying facility described above, wherein the heat exchanger uses waste heat from the cement manufacturing facility (120) as a heat source. According to this, the waste heat of a cement manufacturing facility can be used effectively.

3. In the sludge drying facility described above, the sludge after drying is supplied to a cement manufacturing facility (120). According to this, sludge after drying can be effectively used as a raw material and fuel for cement production. At the same time, the heat efficiency of the entire system can be further improved by utilizing the waste heat of the cement production facility as a heat source of the heat exchanger.

4). In the sludge drying facility described above, the control means controls the amount of circulating air supplied to the heat exchanger (50) based on a difference between a target value and an actual value of the crusher inlet temperature. Sludge drying equipment. According to this, the control accuracy can be further improved.

DESCRIPTION OF SYMBOLS 1 Sludge drying equipment 10 Receiving hopper 11 Supply pump 15 Mixer 21 Air flow meter 22 Thermometer 31 Crusher 35, 36 Cyclone 39 Distributing means 50 Heat exchanger 63 Elevator 65 Raw material tank 67 Through-flow feeder 69 Roots blower 81 Conveyance paths 82-85 Circulation line 87 Gas line 88A Heat exchange line 88B Bypass line 89 Return gas lines 91, 93, 94 Gas line 92 Conveyance path 97 Gas line 120 Cement production equipment 121 Suspension preheater 125 Rotary kiln 127 Combustion gas flow path 135, 136 Cyclone 137 Screw conveyor 138 Roots blowers B1 to B3 Fan P1 Connection P2 Branch RV Rotary valves V1 to V5

Claims (4)

Sludge supply source,
A heat exchanger that raises the temperature of the circulating air;
While drying the sludge with the circulating air, a crusher for crushing the sludge,
A sludge circulation path connecting the upstream and downstream of the crusher;
Solid-gas separation means provided on the downstream side of the crusher in the sludge circulation path,
The sludge circulation path is provided separately, and includes a branching means for discharging part of the sludge after drying from the downstream of the solid-gas separation means,
A mixer that is provided on the downstream side of the solid-gas separation means in the sludge circulation path, mixes and discharges sludge after drying and sludge before drying supplied from the sludge supply source;
The sludge circulation path is connected to the heat exchanger, and has a pipe connection portion for supplying the circulating air to the downstream side of the mixer,
A heat exchange line connected to the sludge circulation path, supplying the circulating air before the temperature rise to the heat exchanger, and returning the circulation air after the temperature rise to the sludge circulation path;
A bypass line provided in parallel with the heat exchange line and returning the circulating air to the sludge circulation path without passing through the heat exchanger;
A temperature measuring means provided between the pipe connection portion and the heat exchanger, for measuring a crusher inlet temperature;
Control means for controlling the amount of circulating air supplied to the heat exchange line,
The crusher is the sludge circulation path and is provided on the downstream side of the pipe connection part,
The said control means controls the supply amount of the circulating air supplied to the said heat exchange line based on the said crusher inlet temperature. The sludge drying equipment characterized by the above-mentioned. In the sludge drying facility according to claim 1,
The heat exchanger uses the waste heat from the cement production facility as a heat source. In the sludge drying equipment according to any one of claims 1 and 2,
The sludge drying equipment is characterized in that the dried sludge is supplied to a cement manufacturing facility. In the sludge drying equipment according to any one of claims 1 to 3,
The sludge drying facility characterized in that the control means controls a supply amount of circulating air supplied to the heat exchanger based on a difference between a target value and an actual value of the crusher inlet temperature.

Images