CN103373801B - Continuous dehydrating method and device for explosive production wastewater and sludge - Google Patents

Abstract

The invention discloses a method and device for continuous dehydration of wastewater sludge from explosive production. The device includes a sludge storage tank, a sludge thermal dehydrator and a belt conveyor, and a sludge pipe is arranged between the sludge storage tank and the thermal dehydrator. , a sludge pump is arranged on the sludge pipe; a spiral preheating pipe is arranged at the bottom of the sludge thermal dehydrator, a spiral steam heating pipe is arranged on the upper part, and a return water pipe is arranged under the spiral steam heating pipe in the sludge thermal dehydrator; A sludge cooling tank is arranged on one side of the sludge thermal dehydrator, and a cold water injection pipe is arranged in the sludge cooling tank. The equipment of the invention improves the dehydration rate of the sludge, and the structure of the dewatered sludge is compact, and the volume of the sludge is small, which is convenient for transportation, storage and treatment. At the same time, the present invention does not need to input chemicals in the dehydration process, reducing environmental pollution.

Description

Continuous dehydration method and device for explosives production wastewater sludge

technical field

The invention belongs to the technical field of sludge dehydration treatment in environmental engineering, and in particular relates to a continuous dehydration device for explosive production wastewater sludge.

Background technique

After the explosive is produced, in order to ensure its storage stability and safety, it is usually made into explosive particle microcapsules, that is, a layer of organic wall material is coated on the surface of the explosive particle. When reused, it is necessary to emulsify the wall material with alkali and surfactant in water, filter and remove it, and use the explosive after drying, and discharge the filtrate to form a certain amount of explosive production wastewater. The wastewater contains a large amount of organic matter in wall materials and surfactants, etc., and the content of organic pollutants is high and the pollution is serious. This kind of wastewater can be treated by acid precipitation to remove the pollutants in the wastewater. After acid analysis, a large amount of water-containing sludge is produced, generally with a water content of 98% to 99%, which is difficult to dewater.

For this kind of sludge dewatering method, conventional sludge dewatering methods such as mechanical filter press dewatering or centrifugal dewatering are adopted. The equipment used mainly includes plate and frame filter press, belt sludge dewatering machine and centrifuge. These conventional dehydration methods and equipment need to add chemical agents, such as polyaluminum chloride and polyacrylamide, to improve the sludge floc structure. Its operation is troublesome, and the dehydration efficiency is low. After dehydration, the moisture content of the solid sludge is still high (generally, the moisture content is more than 75%). The sludge structure is loose and the volume is large, which is not conducive to transportation, storage and treatment.

Contents of the invention

The object of the present invention is to provide a continuous dehydration method and device for sludge produced in the treatment of explosive production wastewater, which can improve the sludge dehydration rate and reduce the sludge volume.

A continuous dehydration method for explosives production wastewater sludge, comprising the following steps:

Step a. The sludge produced by the acid analysis of the explosive production wastewater is discharged into the mud storage tank, and mechanically stirred into a uniform slurry;

Step b. Pump the sludge into the sludge thermal dehydrator and heat it to a temperature of 75-85°C for sludge dehydration. The dehydrated water is returned to the front section of the thermal dehydrator for preheating the sludge, and the hot sludge flows to the cooling tank by itself.

Step c. Pulse spray cold water to the hot sludge flowing to the cooling tank, cool the sludge to a temperature of 30-40°C, make the sludge form a hard block, and flush it out from the outlet at the end of the cooling tank.

Step d. The lumpy sludge falls onto the conveyor belt of the belt conveyor, and is output from the end of the conveyor belt after gravity dehydration on the conveyor belt.

Step b. The heating temperature is preferably 75°C, 80°C or 85°C;

The continuous dehydration device for explosives production wastewater sludge includes a sludge storage tank, a sludge thermal dehydrator and a belt conveyor.

The sludge storage tank is an open cylinder with a vertical mixer inside to stir the discharged sludge into a uniform slurry.

A sludge pipe is arranged between the sludge storage tank and the thermal dehydrator, and a sludge pump is arranged on the sludge pipe. The bottom of the sludge thermal dehydrator is provided with a spiral preheating pipe, the upper part is provided with a spiral steam heating pipe, and the spiral preheating pipe is connected to the return water pipe;

A sludge cooling tank is arranged on one side of the sludge thermal dehydrator, and a cold water injection pipe is arranged in the sludge cooling tank;

The inlet of the return pipe is 15-30cm away from the hot sludge outlet baffle;

The spiral steam heating tube is externally connected to the steam pipeline.

The height of the outlet baffle of the cooling tank is 15-20cm.

A cold water injection pipe is arranged horizontally at the hot sludge inflow end at the bottom of the sludge cooling tank, the inner diameter of the injection pipe is 60-80 mm, and the injection pipe is connected to the cooling water inlet pipe at the bottom of the cooling tank;

There is a row of holes with a diameter of 20-30mm on the top of the spray pipe, and the center distance of the holes is 60-80mm.

The holes are distributed regularly or irregularly;

The water volume is controlled by the hole diameter and the number of holes, and the hole pulse sprays water to cool the inflowing hot sludge, making it cool to form a hard block, and the sludge is washed out from the outlet baffle at the end of the cooling tank and dropped to the belt conveyor for transportation On the belt, the cold water used is the waste water after the separation of mud and water in waste water treatment.

The belt conveyor is placed in the lower part of the cooling tank. The conveyor belt is circular, and the conveyor belt is porous synthetic fiber filter cloth. The sludge in the form of lumps falls onto the conveyor belt for further gravity dehydration and then is output from the end of the conveyor belt.

The belt conveyor is an ordinary belt conveyor, and a U-shaped sump is added under the conveyor belt to collect cooling water and be discharged from the drain pipe of the sump. The width of the sump is the same as that of the filter belt, and the length is more than 2m.

The sludge is pumped into the sludge thermal dehydrator, preheated by the lower spiral preheating tube, and then heated by the upper spiral steam heating tube.

After the sludge heating temperature reaches 75°C, it begins to soften, automatically shrinks and gathers, and floats on the surface of the water layer. The water inside the sludge escapes through the sludge pores and enters the lower water layer by gravity to achieve sludge dehydration; the hot water coming out of the lower layer enters through the return pipe The spiral preheating pipe is used to preheat the sludge. The dehydrated hot sludge flows to the cooling tank through the inlet baffle of the cooling tank between the heating zone of the dehydrator and the sludge cooling tank, and is cooled by pulse water spray to form hard lump sludge. The spiral preheating pipe is connected to the return water pipe, and the hot water released from the sludge is used to preheat the subsequent sludge through heat exchange, so as to save heat energy, reduce treatment costs, and discharge the effluent. The cooling tank outlet baffle height is lower than the hot sludge outlet baffle.

The spiral steam heating pipe is externally connected with a steam pipe, and is used for heating the sludge, so that the sludge is softened, shrunk and aggregated to form a block with a compact structure.

The present invention has the following beneficial effects:

After being treated by the equipment and method of the invention, the water content of the blocky sludge formed after dehydration is lower than 30%, which is far lower than the conventional dehydration method. The structure of the dewatered sludge is dense, and the volume of the sludge is small, only 1/3 to 1/4 of the volume of the dewatered sludge of the plate and frame filter press, belt filter press or centrifuge.

Description of drawings

Fig. 1 is a schematic diagram of a sludge continuous dehydration treatment system according to the present invention

Figure 2 Top view of sludge thermal dehydrator

Figure 3 Sectional view of sludge thermal dehydrator

Fig. 4 Partial enlarged cross-sectional view of the cooling tank, cold water injection pipe, and return water pipe connection of the thermal dehydrator

Explanation of reference signs

1. Sludge storage tank 2. Mixer 3. Sludge pump 4. Return water outlet pipe 5. Steam main pipe 6. Sludge thermal dehydrator 7. Sludge cooling tank 8. Cooling water inlet pipe 9. Belt conveyor 10 , sump 11, return pipe 12, sump drain pipe 13, sludge input pipe 14, spiral preheating pipe 15, spiral steam heating pipe 16, adjustable support 17, cold water injection pipe 18, hot sludge outlet baffle 19. Cooling tank outlet baffle 20. Return hot water inlet

Detailed ways

Refer to Figure 1, Figure 2, Figure 3 and Figure 4.

The present invention provides a continuous dehydration equipment for explosives production wastewater sludge, which comprises three parts: a sludge storage tank 1 , a sludge thermal dehydrator 6 and a belt conveyor 9 . Wherein the sludge storage tank 1 is a cylinder with a vertical mixer 2 inside, and the sludge produced by the acid analysis of the explosives production wastewater is discharged into the sludge storage tank and stirred into a slurry;

The sludge thermal dehydrator 6 includes a spiral preheating pipe 14, a spiral steam heating pipe 15, a cold water injection pipe 17, and a return water pipe 11, and the spiral preheating pipe 14 is connected to the return water outlet pipe 4, the steam main pipe 5, and the sludge input pipe 13 , adjustable support 16;

After the sludge is pumped into the sludge thermal dehydrator, the spiral preheating pipe uses the hot water released from the sludge to preheat through heat exchange, and the steam from the main steam pipe 5 enters the spiral steam heating pipe 14 to heat the sludge until T≥75°C. The sludge is softened, shrunk and aggregated to form compact blocks, and enters the sludge cooling tank 7 through the hot sludge outlet baffle plate 18, and the cold water entering the cooling water inlet pipe 8 cools the sludge temperature to T≤40°C through pulse water spraying. A lump is formed and punched out through the outlet baffle 19 of the cooling tank.

The massive sludge falls onto the conveyor belt of the belt conveyor 9 for further gravity dehydration and then is output from the end, and the extracted water is collected by the sump 10 and then discharged to the waste water treatment system through the drain pipe 12. The structure of the dewatered sludge output from the end of the belt conveyor is compact and hard, and the moisture content is lower than 30%.

The present invention provides a continuous dehydration equipment and operation method for explosives production wastewater sludge, which mainly includes the following steps:

Step a. The sludge produced by the acid analysis of the explosives production wastewater is discharged into the mud storage tank 1, and the mixer 2 is started to stir the sludge into a uniform slurry; the specific process of the sludge generation is that the explosives production wastewater is collected and left to settle. The precipitation time is 24-36 hours; after precipitation, the upper wastewater layer is discharged, and dilute inorganic acid is added to the wastewater to adjust the pH of the wastewater to 2-3; the inorganic acid is hydrochloric acid, sulfuric acid or nitric acid; after adding acid, fill the wastewater with compressed air and expose The air time is 30-60 minutes, so that the pollutants float up to form a sludge layer.

Step b. Pump the sludge into the sludge thermal dehydrator 6 by the sludge pump 3, heat the sludge to 80°C by the spiral preheating pipe 14 and the spiral steam heating pipe 15, and dehydrate the sludge, and the dehydrated water enters from the return pipe 20 enters 11 and flows back to the front section of the thermal dehydrator through the spiral preheating pipe 14 to preheat the sludge, and the effluent is discharged, and the hot sludge flows to the sludge cooling tank 7 by itself.

Step c. Pulse cold water is sprayed from the cold water injection pipe 17 to the hot sludge flowing into the sludge cooling tank 7 to cool the sludge to a temperature of 35° C. and make the sludge form lumps.

Step d. The massive sludge is washed out by the cooling water and falls onto the conveyor belt of the belt conveyor 9. After further gravity dehydration on the conveyor belt, it is output from the end of the conveyor belt. The extracted water is collected by the sump 10 and then passes through the sump drain pipe 12 emissions.

The actual treatment effect shows that the sludge produced by the acid precipitation of the explosives production wastewater is treated by the equipment and method of the present invention without the need for additional chemical agents, and the water content of the massive sludge formed after dehydration is lower than 30%, which is far lower than that of conventional dehydration method. The structure of the dewatered sludge is dense, and the volume of the sludge is small, only 1/3 to 1/4 of the volume of the dewatered sludge of the plate and frame filter press, belt filter press or centrifuge.

Claims (9)

1. an explosive production wastewater mud continuous dehydration device, comprises mud basin, sludge hot dewaterer and ribbon conveyer,

Be provided with sludge pipe between mud basin and hot dewaterer, described sludge pipe arranges sludge pump; Arrange spiral economizer bank bottom described sludge hot dewaterer, top arranges helicoidal stream heating tube, and spiral economizer bank connects backflow water pipe; Described sludge hot dewaterer side arranges mud cooling bath, and described mud cooling bath Base Heat mud flows into end horizontally set cold water injection pipe.

2. explosive production wastewater mud continuous dehydration device as claimed in claim 1; It is characterized in that described playpipe bore 60-80mm, playpipe is connected with cooling bath bottom coohng water water inlet pipe; Described playpipe top has row's diameter 20-30mm eyelet, eyelet center distance 60-80mm; Described eyelet is rule or Non-regular distribute.

3. explosive production wastewater mud continuous dehydration device as claimed in claim 1; It is characterized in that described ribbon conveyer is positioned over cooling bath bottom, conveyer belt is circulating, and conveyer belt is porous synthetic fiber filter cloth.

4. explosive production wastewater mud continuous dehydration device as claimed in claim 3; It is characterized in that described conveyer belt has U-shaped water leg.

5. explosive production wastewater mud continuous dehydration device as claimed in claim 1; It is characterized in that cooling bath is provided with cooling bath outlet damper.

6. explosive production wastewater mud continuous dehydration device as claimed in claim 5; It is characterized in that described sludge hot dewaterer connects mud cooling bath side and arranges hot sludge outlet baffle plate.

7. explosive production wastewater mud continuous dehydration device as claimed in claim 6; It is characterized in that cooling bath outlet damper height is lower than hot sludge outlet baffle plate.

8. adopt an explosive production wastewater mud continuous dehydration method for dewater unit described in any one in claim 1-6, it is characterized in that, comprise the following steps:

The mud that step a. explosive production wastewater acid out produces enters in storage mud tank, and mechanical agitation is pulpous state uniformly;

Mud is pumped into sludge hot dewaterer by step b., and to be heated to temperature be 75-85 DEG C, carries out sludge dewatering, deviate from water and be back to hot dewaterer leading portion for preheating mud, and hot mud is from flowing to cooling bath;

Step c is to flowing to cooling bath hot mud impulse jet cold water, and cooling mud is 30-40 DEG C to temperature, makes mud form lump shape, and it is gone out by cooling bath end outlet;

Steps d. block mud falls in belt of belt conveyor, is exported on the conveyor belt after gravity dehydration by conveyer belt end.

9. explosive production wastewater mud continuous dehydration method as claimed in claim 8, it is characterized in that, described heating-up temperature is 75 DEG C, 80 DEG C or 85 DEG C.