CN103910399B - Rubbish leachate treatment system - Google Patents

Abstract

The invention discloses a garbage leachate treatment system, which comprises an evaporator, a heater and a steam compressor; the evaporator is provided with a steam outlet, a garbage filtrate feed pipe, a concentrate return pipe and a concentrate outlet; the heater is provided with a concentrate Inlet, heater steam inlet, concentrated liquid outlet, condensed water outlet, uncondensed steam outlet; the steam outlet of the evaporator is connected to the steam compressor, and the outlet of the steam compressor is connected to the heater steam inlet of the heater; the evaporator The outlet of the concentrated liquid is divided into two paths, one is connected to the concentrated liquid discharge pump, the other is connected to the forced circulation pump, the forced circulation pump is connected to the concentrated liquid inlet of the heater, and the concentrated liquid outlet of the heater is connected to the concentrated liquid of the evaporator. Liquid return pipe. The heat source of the evaporation system in the present invention mainly adopts the secondary steam generated by itself. It reuses the secondary steam as a heat source.

Description

Garbage leachate treatment system

technical field

The invention relates to a garbage leachate treatment system, in particular to an evaporation system for treating garbage leachate in a garbage incineration plant with low cost, low energy consumption and convenient operation and management, belonging to the technical field of wastewater treatment.

Background technique

With the acceleration of the pace of urbanization in our country, the growth of population and the improvement of people's living standards, urban domestic waste is also increasing day by day. At present, the methods of waste treatment and disposal mainly include landfill, composting, incineration, etc. Compared with traditional landfill and composting, incineration has the advantages of reduction, harmlessness, and resource utilization. has been well developed.

In order to ensure the efficiency of incineration in the process of garbage incineration, fresh garbage needs to be fermented in the garbage storage pit for 3 to 7 days before incineration, and this process produces garbage leachate. The leachate is a kind of toxic and harmful high-concentration organic wastewater that is difficult to treat. It is yellow-brown or gray-brown. The volatilized gas has a strong stench and is harmful to the human body. It can cause nausea, hematuria, dizziness and other symptoms.

Evaporation is a method of treating landfill leachate. Evaporation is a physical process that separates volatile components from non-volatile components. It consists of two parts: heating the solution to boil and vaporize the water and continuously removing the vaporized water. steam. When the landfill leachate is evaporated, the water is boiled out of the leachate and the pollutants remain in the concentrate. All heavy metals and inorganics and most organics are less volatile than water and therefore remain in the concentrate, only some of the volatile hydrocarbons, volatile organic acids and contaminants such as ammonia enter the vapor and end up in the condensate . However, the existing evaporation devices for treating garbage leachate are multi-effect evaporators and horizontal tube falling film evaporators. The disadvantages are complex evaporation devices, high energy consumption, high operating costs, easy scaling, and complicated cleaning.

Contents of the invention

Purpose of the invention: The purpose of the invention is to relate to an evaporation system for treating waste leachate in waste incineration plants with low cost, low energy consumption and convenient operation and management.

Technical solution: The garbage leachate treatment system of the present invention includes an evaporator, a heater and a steam compressor; the evaporator is provided with a steam outlet, a garbage filtrate feed pipe, a concentrated liquid return pipe and a concentrated liquid outlet; the heater is provided with There are a concentrated liquid inlet, a heater steam inlet, a concentrated liquid outlet, a condensed water outlet, and an uncondensed steam outlet; the steam outlet of the evaporator is connected to a steam compressor, and the steam compressor outlet is connected to the heater steam inlet of the heater; The concentrated liquid outlet of the evaporator is divided into two paths, one is connected to the concentrated liquid discharge pump, the other is connected to the forced circulation pump, the forced circulation pump is connected to the concentrated liquid inlet of the heater, and the concentrated liquid outlet of the heater is connected to the evaporator The concentrate return line of the device.

Further, it also includes a condensed water heat exchanger and a gas heat exchanger; the condensed water outlet of the heater is connected to the condensed water heat exchanger; the non-condensed steam outlet of the heater is connected to the gas heat exchanger, and the garbage filtrate is exchanged through the condensed water The waste filtrate feed pipe connected to the evaporator after being heated by the heater and the gas heat exchanger.

Further, the garbage filtrate is first connected to the condensed water heat exchanger, then connected to the gas heat exchanger, and then connected to the garbage filtrate feed pipe of the evaporator.

Further, the garbage filtrate is divided into two paths, which are respectively connected to the gas heat exchanger and the condensed water heat exchanger, and then merged into a garbage filtrate feed pipe connected to the evaporator.

Further, it also includes a condensed water transfer tank, a condensed water tank and a gas-liquid separator; the condensed water outlet of the heater is connected to the condensed water heat exchanger through the condensed water transferred tank; The condensed water outlet of the water tank; the gas heat exchanger is provided with a gas outlet connected to the gas-liquid separator; the gas-liquid separator is provided with a gas outlet and a liquid outlet, wherein the gas discharged from the gas outlet is discharged to the atmosphere, and the liquid outlet is connected to To the condensation water tank; the condensation water transfer tank is provided with a first exhaust pipe, the condensation water tank is provided with a second exhaust pipe, and both the first exhaust pipe and the second exhaust pipe are connected to the gas heat exchanger.

Further, the evaporator is a vertical tank, the heater is a horizontal tank, and the heater is provided with a plurality of heating tube bundles, and the space in the heater is divided into the inside of the heating tube bundle and the outside of the heating tube bundle , the concentrated liquid conducts heat exchange with the steam outside the heating tube bundle in the heating tube bundle.

Compared with the prior art, the present invention has the following beneficial effects: 1. The heat source of the evaporation system of the present invention mainly adopts the secondary steam generated by itself. It reuses the secondary steam as a heat source. After the secondary steam is collected together, the steam compressor is used to increase the pressure and temperature, and then transport it to the heater of the evaporation system as its own heating source, and transfer its own enthalpy to the other side while condensing. Leachate. The heated leachate is heated and evaporated in the evaporator to generate secondary steam, thereby continuously circulating. 2. There is no need to set up a special large-scale cooling device. After the secondary steam used as the heat source is condensed after boosting the pressure and temperature, it will exchange heat with the incoming liquid through the heat exchanger, and leave the system after transferring most of its own heat to the incoming liquid, which not only recovers energy, but also Played the role of cooling down. 3. Lowest energy consumption. It reuses the secondary steam as a heat source, which is equivalent to a multi-effect evaporator, but it does not need steam supply, it only needs a small amount of electric energy to supply the steam compressor, and the secondary steam is boosted to a temperature by the steam compressor. A slightly higher energy level than the secondary steam is sufficient. 4. The evaporation system described in this system evaporates under negative pressure and low temperature, which saves the amount of steam used, and the negative pressure and low temperature evaporation is conducive to reducing the concentration of organic matter in the steam and improving the removal effect of organic matter. 5. Low investment, simple structure and easy operation. The evaporator of the present invention is equivalent to a single-effect evaporator in terms of structure, and equivalent to a multi-effect evaporator in terms of efficacy. It does not have the complicated control system required by the multi-effect evaporator, and the equipment manufacturing cost is also relatively high. Inefficient. 6. The concentrated liquid conducts heat exchange with the steam outside the heating tube bundle in the heating tube bundle of the heater. The concentrated liquid in the heating tube bundle has a fast flow rate and a large impact force, and the heating tube bundle is not easy to scale. The horizontal tube evaporator evaporates by spraying the leachate outside the heating tube bundle, and the outside of the heating tube bundle is prone to fouling. The evaporator and heater designed in the present invention are simple in structure and easy to clean. 7. The input leachate first passes through the condensate heat exchanger to increase the temperature to a certain extent, and then is heated by the steam in the gas heat exchanger, because although the temperature of the steam in the gas is roughly the same as that of the condensate, the heat released by it is mostly Condensation heat can release a large amount of heat when the temperature is lowered, thereby increasing the temperature of the whole garbage leachate before entering the evaporator after preheating, and saving more energy.

Description of drawings

Fig. 1 is a schematic diagram of the garbage leachate treatment system of the present invention.

detailed description

The technical solutions of the present invention will be described in detail below, but the protection scope of the present invention is not limited to the embodiments.

Example:

The garbage leachate treatment system of the present embodiment is shown in Figure 1, comprises evaporator 1, heater 2, steam compressor 3, and evaporator main body is vertical tank, and evaporator top is provided with steam outlet 4, and evaporator middle part Garbage leachate feed pipe 5 and concentrated liquid return pipe 6 are provided, and the concentrated liquid outlet 7 is provided at the lower part of the evaporator; multiple concentrated liquid heating tube bundles 8 are arranged in the heater, and the concentrated liquid outlet 7 of the evaporator is connected to the heater 2 The concentrated liquid inlet 10 of the heating tube bundle is connected through a forced circulation pump 9 , the heater heating tube bundle outlet 12 is connected to the evaporator concentrated liquid return inlet 6 , and the evaporator steam outlet 4 is connected to the heater steam inlet 11 through a steam compressor 3 .

An external steam pipe is arranged inside the evaporator, and the heat source of the external steam pipe is steam from a waste incineration plant. External steam is used to preheat landfill leachate when starting up.

A condensed water outlet 13 is provided at the bottom of the heater, and the condensed water outlet is connected to the condensed water transfer tank 16, which is connected to the condensed water heat exchanger 17, and the garbage leachate feed pipe is also connected to the condensed water heat exchanger. The condensed water enters the condensed water tank 18 after being heat-exchanged by the condensed water heat exchanger. The condensed water tank is provided with a condensed water discharge pipe, and the condensed water enters the next process for treatment.

The heater 2 is provided with a heater non-condensed steam outlet 14, a first exhaust pipe 21 is provided on the upper part of the condensed water transfer tank 16, a second exhaust pipe 22 is provided on the upper part of the condensed water tank 18, and a heater non-condensed steam outlet 14, The first exhaust pipe 21 and the second exhaust pipe 22 are all connected to the gas heat exchanger 19, the outlet of the gas heat exchanger is connected to the gas-liquid separator 20, and the gas outlet of the gas-liquid separator is connected to the vacuum pump 23, and the vacuum pump 23 is connected to the gas-liquid separator. The extracted gas is discharged to the atmosphere, and the liquid outlet of the gas-liquid separator is connected to the condensate tank 18. The condensate heat exchanger 17 and the gas heat exchanger 19 are arranged in parallel. However, the two can also be arranged in series, and, as can be seen from the sixth beneficial effect, the condensate heat exchanger 17 is connected in series first, and then the gas heat exchanger 19 is connected in series, so that the preheating efficiency of the garbage leachate will be higher.

A concentrated liquid discharge pump 15 is connected between the concentrated liquid outlet 7 of the evaporator and the forced circulation pump 9 .

The equipment of the evaporation system works under negative pressure. First, the external steam is passed into the garbage leachate at the bottom of the evaporator to heat the garbage leachate, so that the garbage leachate evaporates under negative pressure, and the water and ammonia in the leachate become steam. It rises to the upper part of the evaporator, and then is compressed by a steam compressor and the temperature rises to slightly higher than the boiling point. The concentrated liquid in the tube bundle, after the temperature of the concentrated liquid rises, returns to the evaporator for evaporation again, and the cycle continues. This system uses the steam generated by evaporation itself to heat the leachate of garbage, which saves energy.

After the evaporation starts, the condensed water and steam produced by the system have a higher temperature and can be recycled. Before the garbage leachate enters the evaporator, it exchanges heat with condensed water, non-condensable steam/a small amount of non-condensable steam in the condensed water heat exchanger and the gas heat exchanger. When the temperature of the garbage leachate increases, the temperature of the condensed water and steam decreases and is recovered Energy is saved, and there is no need to set up a special cooling device. After the system is in normal operation, the external steam can be turned off, and only the energy generated by the system itself and the electric energy of the steam compressor can be used to make the evaporation run stably.

The condensed water after heat exchange enters the next treatment process, which can be ammonia stripping, ion exchange and other processes. The non-condensable gas after gas-liquid separation is pumped out by a vacuum pump and put into the incinerator of the waste incineration plant to prevent secondary pollute. The concentrated liquid is discharged continuously or intermittently through the discharge pump, and then enters the garbage bin and then enters the incinerator for incineration.

As stated above, while the invention has been shown and described with reference to certain preferred embodiments, this should not be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. a garbage leachate treatment system is characterized in that, comprises evaporator (1), heater (2) and steam compressor (3); Evaporator (1) is provided with steam outlet (4), garbage filtrate enters Material pipe (5), concentrated liquid return pipe (6) and concentrated liquid outlet (7); heater (2) is provided with concentrated liquid inlet (10), heater steam inlet (11), concentrated liquid outlet (12), Condensed water outlet (13), uncondensed steam outlet (14); the steam outlet (4) of the evaporator (1) is connected to the steam compressor (3), and the outlet of the steam compressor (3) is connected to the heater (2) The steam inlet (11) of the heater; the concentrate outlet (7) of the evaporator is divided into two paths, one path is connected to the concentrate discharge pump (15), and the other path is connected to the forced circulation pump (9), and the forced circulation The pump (9) is connected to the concentrate inlet (10) of the heater (2), and the concentrate outlet (12) of the heater (2) is connected to the concentrate return pipe (6) of the evaporator (1). 2. The landfill leachate treatment system according to claim 1, characterized in that it comprises a condensed water heat exchanger (17) and a gas heat exchanger (19); the condensed water outlet (13) of the heater (2) communicates with To the condensed water heat exchanger (17); the uncondensed steam outlet (14) of the heater (2) is connected to the gas heat exchanger (19), and the garbage filtrate passes through the condensed water heat exchanger (17) and the gas heat exchanger ( 19) After heating, it is connected to the garbage filtrate feed pipe (5) of the evaporator (1). 3. The garbage leachate treatment system according to claim 2, characterized in that the garbage filtrate is first connected to the condensed water heat exchanger (17), then connected to the gas heat exchanger (19), and then connected to the evaporator (1) Garbage filtrate feed tube. 4. The garbage leachate treatment system according to claim 2, characterized in that the garbage filtrate is divided into two paths, which are respectively connected to the gas heat exchanger (19) and the condensed water heat exchanger (17) and then merged into one path to communicate Landfill filtrate feed to evaporator (1). 5. garbage leachate treatment system according to claim 2 is characterized in that, comprises condensed water transfer tank (16), condensed water tank (18) and gas-liquid separator (20); The condensed water of described heater The outlet (13) is connected to the condensed water heat exchanger (17) through the condensed water transfer tank (16); the condensed water heat exchanger (17) is provided with a condensed water outlet connected to the condensed water tank (18); the gas heat exchanger ( 19) is provided with a gas outlet communicating with the gas-liquid separator (20); the gas-liquid separator (20) is provided with a gas outlet and a liquid outlet, wherein the gas discharged from the gas outlet is discharged to the atmosphere, and the liquid outlet is connected to the condensed water Tank (18); described condensation water transfer tank (16) is provided with first exhaust pipe (21), and described condensation water tank (18) is provided with second exhaust pipe (22), and first exhaust pipe (21 ) and the second exhaust pipe (22) are connected to the gas heat exchanger (19). 6. garbage leachate treatment system according to claim 2, is characterized in that, described evaporator (1) is a vertical tank body, and described heater (2) is a horizontal tank body, and heater ( 2) There are multiple heating tube bundles inside, and the space in the heater is divided into the inside of the heating tube bundle and the outside of the heating tube bundle, and the concentrated liquid performs heat exchange with the steam outside the heating tube bundle in the heating tube bundle.