JP2001070996A - Direct drying facility of sludge slurry utilizing waste heat of cogeneration gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the initial operation cost, maintenance cost and chemical cost, and thus the total operation cost for drying a sludge slurry, by utilizing the subject direct drying facility having a concentrator, a mixing granulator, dryer, a cogeneration electric power gas turbine and a classifier but having no dehydrator. SOLUTION: A direct drying facility of a sludge slurry utilizing waste heat of a cogeneration gas turbine has a concentrator 11 for concentrating high moisture slurry of sludge such as cleaned water or sewage, a mixing granulator 12 for mixing the concn. sludge slurry with dry sludge to form a sludge cake, a dryer 13 for drying the sludge cake, a cogeneration electric power gas turbine 14 sending waste heat to the dryer in order to utilize the same as a heat source and a classifier for classifying the dry sludge from the dryer into a necessary circulating amt. of the dry sludge to the mixing granulator and a dry product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a facility for directly drying sludge slurry using cogeneration gas turbine exhaust heat. The facility is applied to wastewater treatment at water treatment plants that produce drinking water from river water and lake water, and sewage treatment plants.

[0002]

2. Description of the Related Art Conventionally, sludge generated in a wastewater treatment system in a water purification plant is concentrated in a concentration tank to an SS concentration of about 1 to 10%, and the obtained concentrated sludge slurry is subjected to a dehydrator to obtain a water content of 50 to 80%. After dewatering and reducing the volume of the dewatered cake, or removing water to the same extent on a solar drying bed, it can be landfilled as it is, or it can be dried to 30 to 40% moisture with a dryer using fuel after dehydration After granulation, it was recycled as greening soil.

[0003]

In the above dewatering step, in order to obtain a dewatered cake by dewatering the concentrated sludge slurry, lime is added to the slurry as a filter aid in an amount of 20 to 30%.
There is a case where a chemical injection type dehydrator for adding and increasing a filtration speed is used, and a case where a concentrated sludge slurry is directly added to a dehydrator without adding lime to use a chemical injection type dehydrator.

In the former case, since the filtration speed is generally 5 to 10 times faster than the latter, the dehydrator becomes compact. However, the amount of dehydrated cake generated is increased by the amount of lime added, and the cost is increased due to the addition of lime. Is expensive. On the other hand, in the latter case, the dehydration energy is large, and the dehydrator becomes large, resulting in high cost. In the former, the pH is increased by adding lime.
It is difficult to use sludge effectively. Also, in any case, the water from the dehydrator may contain bacteria,
In many cases, heat disinfection with steam or the like is required, and in water purification plants, rivers are often discharged as they are.

[0005] The present invention provides a facility for directly drying sludge slurry capable of solving the above problems.

[0006]

SUMMARY OF THE INVENTION The present invention provides a concentrator for concentrating a high moisture slurry of sludge such as purified water and sewage, a mixing granulator for mixing the concentrated sludge slurry with dry sludge to form a sludge cake, A dryer that dries the sludge cake, a gas turbine for cogeneration power generation that sends waste heat to use as a heat source for the dryer, and the required amount of dried sludge from the dryer to the mixing granulator and the dried product This is a direct drying facility for sludge slurry using cogeneration gas turbine exhaust heat, which is equipped with a classifier that divides the sludge slurry into sludge slurry.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In a water purification plant, as shown in FIG. 1, a mechanical or membrane type concentrator (11) is used in order to increase the concentration of a high-moisture slurry, preferably about 15 to 20%. Concentrate to SS concentration. The concentrated sludge slurry is sent to a mixing granulator (12) where it is mixed with the dried sludge to form a sludge cake having a water content of about 50%. The sludge cake is sent to a dryer (13) where the sludge is dried to a moisture content of 20% or less.

A gas turbine for cogeneration power generation (1
The exhaust gas is sent from 4) to the dryer (13) for use as a heat source of the dryer (13). The exhaust gas that has passed through the dryer (13) is sent to the processing device, where it is processed.

The dried sludge discharged from the dryer (13) is classified into a classifier (15).
, Where a part of the dried sludge is classified and mixed with a mixing granulator (1
Circulate to 2) to make sludge cake with about 50% moisture.

A gas turbine for cogeneration power generation (1
Instead of sending exhaust gas from 4) to the dryer (13), a boiler may be installed at the subsequent stage of the gas turbine (14), and a heat medium such as steam generated from turbine exhaust gas may be used as a heat source of the dryer.

Table 1 shows the water content and the like of the high moisture slurry, the concentrated sludge slurry, the sludge cake, the dried sludge and the like in FIG.

[0012]

[Table 1]

[0013]

As described above, the direct drying equipment for sludge slurry according to the present invention comprises a concentrator, a mixing granulator, a dryer, a gas turbine for cogeneration power generation, and a classifier, and Because it does not have a machine, initial costs and maintenance costs for operating the facility are low,
In addition, the drug cost is also reduced, and thus, a reduction in total operating costs can be achieved.

[0014] Further, since the cogeneration gas turbine is cost-effectively balanced with the amount of power generation, the fuel efficiency of the dryer using the calorific value of the exhaust gas is reasonable and economical.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a facility for directly drying sludge slurry according to the present invention.

[Explanation of symbols]

 11: Concentrator 12: Mixing granulator 13: Dryer 14: Gas turbine for cogeneration power generation 15: Classifier

Claims (1)

[Claims] 1. A concentrator for concentrating a high moisture slurry of sludge such as purified water or sewage, a mixing granulator for mixing a concentrated sludge slurry with a dry sludge to form a sludge cake, and a dryer for drying a sludge cake. Equipped with a gas turbine for cogeneration power generation that sends waste heat to use as a heat source for the dryer, and a classifier that separates the dried sludge from the dryer into the required amount of circulation to the mixing granulator and the dried product. Direct drying equipment for sludge slurry using cogeneration gas turbine exhaust heat.