JPS62111129A - Waste water treatment device for recovering power by gas turbine - Google Patents

Abstract

PURPOSE:To improve the efficiency of power recovery by increasing temperature of exhaust gas generated in a waste water treatment device to a high value by a heater and introducing the hot waste water into a gas turbine. CONSTITUTION:Gas which is generated in a waste water treating high pressure oxidizer 1 is fed to a heater 3 via a separator 2. After increasing temperature of the gas by the burner 4 of the heater 3, the gas is carried into a high pressure gas turbine 5. The gas is further carried into a low pressure gas turbine 6 via a reheater 7 to drive a generator 8. Hence the efficiency of power recovery from the exhaust gas can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION Although there are various methods for treating wastewater, the treatment of sludge generated by the reaction remains an unresolved problem. A multi-stage hearth method for incinerating this waste, and ways to turn it into fertilizer and construction materials are being explored. On the other hand, the wet combustion method, in which organic matter is completely combusted in water, does not generate such sludge and is a preferable system. However, this method requires expensive equipment because the wastewater and air are brought to a high pressure of 700 atmospheres or more, and is often not economically viable. The present invention
To solve this problem, the generated high-pressure gas, which is mainly a mixture of unreacted air and carbon dioxide gas, is passed through a heater to create high-pressure, high-temperature gas, which is then guided to a gas turbine to recover power. In this way, the wastewater treatment device can also be used as a high-efficiency power generation device, greatly improving economic efficiency. As the high-pressure compressor for this plant uses isothermal compression and high efficiency, its power generation efficiency will be sufficiently high.

Next, there is the activated sludge method as a simpler method of wastewater treatment.As mentioned above, this method has the drawback of generating sludge, but it is still an effective method and many attempts have been made to improve it. One of these is a process called the deep shaft process, in which the reaction is carried out in a deep well-like hole. Some of these are quite deep, so the water pressure is high, and the air that blows in here is also high pressure and roaring. Therefore, the partial pressure of air is also high, and the solubility in wastewater is also high. In addition, because of the high pressure, air bubbles are small and uniformly dispersed in water, making it suitable for activated sludge reactions, and the air utilization rate increases nearly 10 times compared to atmospheric pressure systems. This method does not require space, does not require a pressure vessel, and does not require a high-pressure pump, but there are cases where a deep well is not suitable for the geology and there are problems with AA.

In contrast, in the present invention, a pressure vessel is provided on the ground, and the pressure thereof is approximately IO atmospheric pressure. This is equivalent to a deep well of about 100 meters. In this case as well, the mixture of unreacted air and carbon dioxide that is generated is heated by a heater and guided to a gas turbine to recover power. As the fuel for this heater, if the heat produced by drying and burning the generated sludge is used, sludge treatment can be done at the same time, which is extremely economical. Furthermore, even if fuel is used for auxiliary combustion, it is effectively utilized and does not harm economic efficiency. The compressor for this plant uses isothermal compression with high efficiency, so its power recovery efficiency is sufficient.

Next, to explain the details with reference to the drawings, FIG. 1 shows the overall structure of the wet combustion method of the present invention. In Figure i, 1 is a high-pressure oxidizer for wastewater treatment. Since it is a pressure-resistant container with a pressure of 100 atmospheres or more, it is shaped like a tall tower with a small diameter. Inside this, at a temperature of around 300 degrees Celsius,
Organic matter is oxidized by high-pressure air and becomes carbon dioxide and water, and the generated gas is separated from the water surface and led to the top. 2 is a separator for the water droplets, which allows the water to exit as dry gas. 3 is a heater that heats this gas to raise its temperature, which is 50 degrees Celsius required for the gas turbine.
Raise the temperature to 0-100 degrees. 4 is a burner for this heater 3, and the fuel is oil, gas, etc.

Also, instead of a burner, a stoker for solid fuel can be used. 5 is a high-pressure gas turbine, and since the gas pressure is high, it is expanded in multiple stages of high pressure and low pressure. 6 is a low pressure gas turbine. Reference numeral 7 denotes a reheater, which heats the gas that has become low temperature after being expanded by the high-pressure gas turbine 5 again to increase cycle efficiency. The combustion gas from the heater 3 is bypassed from the middle and guided to the reheater 7 for heating.

Reference numeral 8 denotes a generator, which is powered by a high-pressure gas turbine 5 and a low-pressure gas turbine 6. 9 is an air compressor, which is close to isothermal compression and has high efficiency.

Reference numeral 10 denotes an air preheater, which uses exhaust heat from the heater 3 and the low pressure gas turbine 6 to preheat high pressure air and improve efficiency. Reference numeral 11 is a high-pressure pump for wastewater, and a highly efficient diaphragm pump is used. Reference numeral 12 denotes a hydraulic turbine that recovers the pressure energy of the waste water that has completed the reaction to drive the high-pressure pump 11. 13 is a wastewater preheater that recovers thermal energy from wastewater and preheats new wastewater.

Next, in FIG. 2, this is an overall structural diagram in the case of an activated sludge system, and 1 is a reactor for wastewater treatment. The pressure in this reactor is usually around 10 atmospheres. This also results in a narrow diameter tower pressure vessel. Activated sludge is growing in this chamber, and the organic matter in the wastewater is decomposed in the presence of air, generating a mixture of air and carbon dioxide, which is separated from the water surface and introduced to the top of the reactor. It will be destroyed. 2 is a separator for the water droplets, which allows the water to exit as dry gas. Reference numeral 3 denotes a heater that heats this gas to raise its temperature to a temperature of soo-goo degrees Celsius required for the gas turbine. In this case, the pressure is as low as 10 atmospheres, so there is no reheating. 14 is a combustion stoker for this heater 3, and 14 is a combustion stoker for this activated sludge system, which converts the sludge generated in this activated sludge system into ordinary fuel such as coal. Incinerate with auxiliary combustion. This allows the energy of auxiliary combustion to be used effectively, and the sludge is completely treated. 5 is a gas turbine, which in this case may have a single stage. 6 is the power generation rock. 7 is an air compressor, which is close to isothermal compression and has high efficiency. 8 is a pump for waste water, and a high efficiency diaphragm pump is used. Reference numeral 9 denotes a hydraulic turbine that recovers the pressure energy of the waste water that has completed the reaction to drive the pump 8 .

[Brief explanation of drawings]

FIG. 1 is an overall structural diagram of the wet combustion method. Second
The figure shows the overall structure of the activated sludge system.

Claims (1)

[Claims] Exhaust gas generated by systems that chemically oxidize organic matter in wastewater by blowing high-pressure, high-temperature air into high-temperature wastewater in a high-pressure container, or biologically decompose organic matter using activated sludge in a high-pressure container. Wastewater treatment equipment uses a heater to raise the temperature of water to a high temperature, guides it to a gas turbine to generate power, and recovers the power with the gas turbine.