CN107840515A - A slag and gray water treatment system - Google Patents

Abstract

The invention provides a slag and grey water treatment system, which belongs to the technical field of coal gasification and is used for solving the problem that the traditional slag and grey water treatment system cannot reasonably utilize flash steam to cause waste of water resources and energy, and the slag and grey water treatment system comprises: the traditional slag and grey water treatment system is used for recycling black water output by the gasification and synthesis gas washing system; and the hydraulic turbine system is connected between the gasification and synthesis gas washing system and the traditional slag and grey water treatment system and is used for recovering the pressure energy of the black water and converting the pressure energy of the black water into kinetic energy so as to convey the process water recovered and treated by the traditional slag and grey water system back to the gasification and synthesis gas washing system for recycling. The slag and grey water treatment system provided by the invention can achieve the effects of saving energy and reducing consumption.

Description

A slag and gray water treatment system

technical field

The invention relates to the technical field of coal gasification, in particular to a slag and gray water treatment system.

Background technique

In view of my country's endowment characteristics of "rich in coal, lack of oil, and little gas" and the current situation of the development of the coal chemical industry, in recent years, the state has promoted the clean and efficient use of coal and ensured national energy security on the one hand; Green development principles for total energy consumption and intensity.

Coal gasification is the gas head of modern coal chemical industry, and it is also a major consumer of water and electricity in modern coal chemical industry. In the energy consumption composition of coal-to-ammonia plants, the energy consumption of coal gasification units (including air separation units) accounts for more than 85%, and the water consumption of coal gasification technology mainly lies in the water consumption of primary coal gasification and the subsequent deep processing of gasification synthesis gas process water consumption. Therefore, coal gasification is an important part of saving water and reducing consumption in modern coal chemical industry.

The slag and ash water treatment system plays an important role in the process of coal gasification to realize energy recovery and water recycling, and is an important part of coal gasification. The circulating water consumed by the system accounts for 70% to 80% of the entire gasification system, and the circulating water consumed by flash steam cooling accounts for more than 80% of the consumption of the slag and gray water treatment system. However, there is no effective way to reasonably Recycling the energy of flash steam and reducing the use of circulating water, resulting in waste of water resources and energy.

Contents of the invention

In order to solve the problem that the traditional slag and gray water treatment system cannot rationally utilize flash steam, resulting in waste of water resources and energy, the present invention provides a slag and gray water treatment system that can recover the energy of flash steam, thereby saving the consumption of circulating water, To achieve the purpose of saving energy and reducing consumption.

A slag and gray water treatment system provided by the invention comprises:

The traditional slag and gray water treatment system is used to recycle the black water output from the gasification and syngas scrubbing system;

An organic Rankine cycle system is connected to the waste gas outlet of the traditional slag and gray water treatment system, and is used to recover and utilize the heat energy in the waste gas of the traditional slag and gray water treatment system.

In a specific implementation, the slag and gray water treatment system also includes:

A hydraulic turbine system, connected between the gasification and syngas scrubbing system and the traditional slag and gray water treatment system, is used to recover the pressure energy of the black water and convert the pressure energy of the black water As kinetic energy, the process water recovered and treated by the traditional slag and gray water treatment system is transported back to the gasification and syngas scrubbing system for recycling.

In a specific embodiment, the hydraulic turbine system includes a hydraulic turbine and a centrifugal pump;

The liquid input end of the hydraulic turbine is connected to the output end of the gasification and syngas scrubbing system, the liquid output end is connected to the traditional slag and gray water treatment system, and the energy output end is connected to the control of the centrifugal pump terminal connection;

The inlet of the centrifugal pump is connected to the process water output of the traditional slag and gray water treatment system, and the outlet is connected to the water inlet of the gasification and syngas scrubbing system.

In a specific embodiment, the organic Rankine cycle system includes: a segmented evaporator, a screw expander, a generator, a condenser, and an organic working medium pump;

The heat source inlet of the segmented evaporator is connected to the exhaust gas outlet of the traditional slag and gray water treatment system, the heat source outlet is connected back to the traditional slag and gray water treatment system, and the organic working medium output is connected to the screw expander The air inlet of the screw expander is connected with the heat source inlet of the condenser; the heat source outlet of the condenser is connected with the input end of the organic working medium pump; the organic working medium pump The output end is connected with the organic working medium input end of the sectional evaporator; the screw expander is also connected with the control end of the generator.

In a specific embodiment, the traditional slag and gray water treatment system includes: a three-stage flash evaporation system, an oxygen removal system, and a sedimentation clarification system;

The high-pressure flash inlet of the three-stage flash system is connected to the black water output of the hydraulic turbine system, and the high-pressure flash outlet of the three-stage flash system is connected to the section of the organic Rankine cycle system The inlet of the high-temperature section of the evaporator, the outlet of the high-temperature section of the segmented evaporator of the organic Rankine cycle system is connected to the low-pressure flash inlet of the three-stage flash evaporation system, and the low-pressure flash evaporation of the three-stage flash evaporation system is discharged The port is connected to the vacuum flash inlet of the three-stage flash evaporation system, and the low-pressure flash vapor outlet of the three-stage flash evaporation system is connected to the input end of the oxygen removal system; the vacuum flash outlet of the three-stage flash evaporation system Connect the segmented evaporator low-temperature section inlet of the organic Rankine cycle system, and the segmented evaporator low-temperature section of the organic Rankine cycle system is connected back to the three-stage flash system; the three-stage flash system The final flash liquid output end of the settling clarification system is connected with the liquid water input end of the settling clarification system, the liquid water output end of the settling clarification system is connected with the liquid water input end of the deaeration system, the liquid state of the deaeration system is The water output end is connected to the heating pipe inlet of the three-stage flash evaporation system, and the heating pipe outlet of the three-stage flash evaporation system is connected to the hydraulic turbine system as the process water output end.

In a specific embodiment, the black water output from the gasification and syngas scrubbing system includes: black water from a gasification furnace, black water from a scrubber, and black water from a cyclone separator.

The beneficial effects of above-mentioned technical scheme of the present invention are as follows:

In the above scheme, the organic Rankine system is used to recover the energy of the waste heat flash steam discharged from the traditional slag and gray water treatment system. On the one hand, it reduces the power consumption of the entire gasification device. The amount of circulating water for process cooling flash steam indirectly saves the amount of fresh water replenishment in the gasification system, achieving the purpose of saving energy and reducing consumption.

Description of drawings

Fig. 1 is a schematic structural view of a slag and gray water treatment system provided by an embodiment of the present invention;

Figure 2 is a schematic structural view of another slag and gray water treatment system provided by an embodiment of the present invention;

Fig. 3 is a schematic structural diagram of another slag and gray water treatment system provided by an embodiment of the present invention.

[Description of Reference Signs]

1. Traditional slag and gray water treatment system, 2. Hydraulic turbine system,

3. Organic Rankine cycle system, 4. Hydraulic turbine,

5. Centrifugal pump, 6. Sectional evaporator,

7. Screw expander, 8. Generator,

9. Condenser, 10. Organic working medium pump,

11. Three-stage flash evaporation system, 12. Settling clarification system,

13. Deoxygenation system.

Detailed ways

An embodiment of the present invention provides a slag and gray water treatment system, as shown in Figure 1, the system includes a traditional slag and gray water treatment system 1 and an organic Rankine cycle connected to the waste gas outlet of the traditional slag and gray water treatment system 1 System 3; Among them, the traditional slag and gray water treatment system 1 is used to recycle the black water output from the gasification and syngas scrubbing system; the organic Rankine cycle system 3 is used to recycle the traditional slag and gray water treatment system 1 Heat energy in exhaust gases. In the prior art, the original process of black water from the gasification and syngas scrubbing system is sent to the three-stage flash system after being decompressed by the regulating valve, and the pressure of the black water can be wasted. Ken circulation system further recovers the heat energy of the waste heat steam discharged from the traditional slag and gray water treatment system, on the one hand, it reduces the power consumption of the entire gasification unit, on the other hand, while recovering the heat energy of the flash steam, it greatly reduces the cycle of cooling the flash steam in the original process The amount of water used indirectly saves the fresh water replenishment of the gasification system and achieves the purpose of saving energy and reducing consumption.

In another specific embodiment, as shown in FIG. 2 , the slag and gray water treatment system provided by the present invention further includes a system connected between the gasification and syngas scrubbing system and the traditional slag and gray water treatment system 1 A hydraulic turbine system 2, the hydraulic turbine system 2 is used to recover the pressure energy of the black water, and convert the pressure energy of the black water into kinetic energy to recycle the traditional slag and gray water treatment system 1 The final process water is sent back to the gasification and syngas scrubbing system for recycling. In this embodiment, the pressure energy of the black water is recovered through the hydraulic turbine system 2, and the pressure energy is converted into kinetic energy, and the process water recovered by the slag and gray water system is gasified and recycled by the syngas scrubbing system, saving the pressure reducing valve consumption, simple structure, and low equipment cost.

Preferably, as shown in Figure 3, the hydraulic turbine system 2 may include a hydraulic turbine 4 and a centrifugal pump 5; wherein, the liquid input end of the hydraulic turbine 4 is connected to the gasification and syngas scrubbing system The output end is connected, the liquid output end of the hydraulic turbine 4 is connected to the traditional slag and gray water treatment system 1, the energy output end of the hydraulic turbine 4 is connected to the control end of the centrifugal pump 5; the inlet of the centrifugal pump 5 is connected to the traditional slag and the process water output of the gray water treatment system 1, and the outlet of the centrifugal pump 5 is connected to the water inlet of the gasification and syngas scrubbing system. In this embodiment, the hydraulic turbine 4 recovers the pressure energy of the black water, converts the pressure energy into kinetic energy to drive the centrifugal pump 5, and the centrifugal pump 5 sends the process water recovered from the slag and gray water system to the gasification and synthesis gas washing system Recycling. The operation is convenient and simple, the number of pressure reducing valves in the system is reduced, and the equipment cost is reduced.

Preferably, as shown in Figure 3, the organic Rankine cycle system 3 may include: a segmented evaporator 6, a screw expander 7, a generator 8, a condenser 9, and an organic working medium pump 10; wherein, the segmented The heat source inlet of the evaporator 6 is connected to the waste gas outlet of the traditional slag and gray water treatment system 1, the heat source outlet is connected back to the traditional slag and gray water treatment system 1, and the output end of the organic working medium is connected to the air inlet of the screw expander 7; The gas outlet of the expander 7 is connected to the heat source inlet of the condenser 9; the heat source outlet of the condenser 9 is connected to the input end of the organic working medium pump 10; The quality input end is connected; the screw expander 7 is also connected with the control end of the generator 8. In this embodiment, the waste gas from the traditional slag and gray water treatment system 1 is input into the sectional evaporator 6 for heat exchange with the organic working medium. The organic working medium absorbs the heat in the waste heat steam and then evaporates. The evaporated organic working medium is Work done in the screw expander 7 drives the generator 8 to generate electricity, and finally the organic working medium is condensed by the condenser 9 and sent back to the segmented evaporator 1 by the organic working medium pump 10 to complete a cycle.

Preferably, as shown in Figure 3, the traditional slag and gray water treatment system 1 may include: a three-stage flash system 11, an oxygen removal system 13, and a sedimentation clarification system 12; wherein, the high-pressure flash evaporation of the three-stage flash system 11 The inlet is connected to the black water output end of the hydraulic turbine 4, the high-pressure flash outlet of the three-stage flash evaporation system 11 is connected to the inlet of the first heat exchange tube of the organic Rankine cycle system 3, and the first heat exchange tube of the organic Rankine cycle system 3 The outlet of the heat pipe is connected to the low-pressure flash inlet of the three-stage flash evaporation system 11, that is, after the three-stage flash evaporation system 11 performs high-pressure flash evaporation on the black water output by the hydraulic turbine 4, the high-pressure flash steam is input into the organic Rankine cycle system 3 The first heat exchange tube (such as the high-temperature evaporation section of the segmented evaporator of the Organic Rankine cycle system 3) performs heat exchange, and the heat of the high-pressure flash steam is used to heat the organic working fluid in the Organic Rankine cycle system 3, and then The high-pressure flash steam becomes liquid and enters the low-pressure flash section. The low-pressure flash evaporation outlet of the three-stage flash evaporation system 11 is connected to the vacuum flash evaporation inlet of the three-stage flash evaporation system 11, and the low-pressure flash evaporation gas outlet of the three-stage flash evaporation system 11 is connected to the input end of the oxygen removal system 13, That is: the low-pressure flash section performs low-pressure flash on the output stream after the heat exchange between the high-pressure flash and the organic Rankine cycle system 3, and the obtained low-pressure flash gas is input into the oxygen removal system 13 for deoxygenation, and the liquid output from the low-pressure flash is Enter the vacuum flash section. The vacuum flash evaporation outlet of the three-stage flash evaporation system 11 is connected to the second heat exchange tube inlet of the organic Rankine cycle system 3, and the second heat exchange tube outlet of the organic Rankine cycle system 3 is connected back to the three-stage flash evaporation system 11, namely: The vacuum flash steam produced by the vacuum flash evaporation section is input to the second heat exchange tube of the organic Rankine cycle system 3 (for example, the low-temperature evaporation section of the segmental evaporator of the organic Rankine cycle system 3) for heat exchange, and the heat of the vacuum flash steam It is used for further heating and evaporating the organic working fluid in the organic Rankine cycle system 3. The final flash liquid output port of the three-stage flash evaporation system 11 is connected to the liquid water input port of the settling clarification system 12, so that the liquid output from the vacuum flash section enters the settling clarification system 12 for sedimentation. The liquid water output end of the sedimentation clarification system 12 is connected with the liquid water input end of the deaeration system 13, the liquid water output end of the deaeration system 11 is connected with the heating pipeline inlet of the three-stage flash evaporation system 11, and the three-stage flash evaporation system 11 The outlet of the heating pipeline is used as the output end of the process water to connect with the hydraulic turbine system 2, that is, the treated liquid water output from the deaeration system 11 is heated by the three-stage flash evaporation system 11 and then output to the hydraulic turbine system 2, and is fed to the hydraulic turbine system 2 by The hydraulic turbine system 2 is sent back to the gasification and syngas scrubbing system for reuse.

Preferably, the black water output from the gasification and syngas scrubbing system includes: black water from a gasification furnace, black water from a scrubber, and black water from a cyclone separator.

The slag and gray water treatment system provided by the embodiment of the present invention will be described below through specific examples.

Embodiment one

As shown in FIG. 3 , the black water from the gasification furnace, scrubber and cyclone separator from the gasification and syngas scrubbing system enters the three-stage flash system 11 after passing through the hydraulic turbine 4 . After flash evaporation, the high flash gas and true flash gas enter the segmented evaporator 6 respectively, the true flash gas enters the low-temperature evaporation section of the segmented evaporator 6, and the high flash gas enters the high-temperature evaporation section of the segmented evaporator 6, which are used in the organic industry. qualitative evaporation. The organic working medium vapor exiting the segmented evaporator 6 expands in the screw expander 7 to perform work, and drives the generator 8 to generate electricity. The organic working medium exhaust steam exiting the screw expander 7 is cooled to a liquid state by circulating water in the condenser 9, and then sent to the segmented evaporator 6 through the organic working medium pump 10 to complete an organic Rankine cycle.

The liquid after the three-stage flash evaporation is sequentially sent to the sedimentation clarification system 12, the oxygen removal system 13, and the three-stage flash evaporation system 11 to be heated, and the hydraulic turbine 4 drives the centrifugal pump 5 to recover the traditional slag and gray water treatment system. The process water is sent back to the gasification and syngas scrubbing system for recycling.

The embodiment of the present invention uses the energy recovered by the hydraulic turbine and the screw expander. On the one hand, the power consumption of the entire gasification device is reduced. On the other hand, while the heat energy of the flash steam is recovered, the amount of circulating water used to cool the flash steam in the original process is greatly reduced. , which indirectly saves the amount of fresh water replenishment in the gasification system and achieves the purpose of saving energy and reducing consumption.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, these improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (6)

1. a kind of slag and grey water treatment system, it is characterised in that including：

Traditional slag and grey water treatment system, for being recycled to the Heisui River of gasification and the output of synthesis gas washing system；

Organic rankine cycle system, it is connected with the waste gas outlet of traditional slag and grey water treatment system, for recycling State the heat energy in the waste gas of traditional slag and grey water treatment system.

2. slag as claimed in claim 1 and grey water treatment system, it is characterised in that the slag and grey water treatment system also wrap Include：

Hydraulic turbine system, be connected to the gasification and synthesis gas washing system and traditional slag and grey water treatment system it Between, for reclaiming the pressure energy in the Heisui River, the pressure energy in the Heisui River is converted into kinetic energy with by traditional slag and buck Process water after processing system recycling is transmitted back in the gasification and synthesis gas washing system and recycled.

3. slag as claimed in claim 2 and grey water treatment system, it is characterised in that it is saturating that the hydraulic turbine system includes fluid power Gentle centrifugal pump；

The fluid input port of the hydraulic turbine is connected with the output end of the gasification and synthesis gas washing system, fluid output port It is connected with traditional slag and grey water treatment system, energy output end is connected with the control terminal of the centrifugal pump；

The centrifugal pump inlet is connected with the process water output end of traditional slag and grey water treatment system, outlet and the gasification And the water inlet connection of synthesis gas washing system.

4. slag as claimed in claim 1 and grey water treatment system, it is characterised in that the organic rankine cycle system includes： Segmented evaporator, screw expander, generator, condenser, organic working medium pump；

The thermal source inlet of the segmented evaporator is connected with the waste gas outlet of traditional slag and grey water treatment system, and thermal source goes out Mouth connects back to traditional slag and grey water treatment system, and organic working medium output end is connected with the air inlet of the screw expander； The gas outlet of the screw expander is connected with the thermal source inlet of the condenser；The thermal source outlet of the condenser has with described The input connection of machine working medium pump；The output end of the organic working medium pump and the organic working medium input of the segmented evaporator Connection；Control terminal of the screw expander also with the generator is connected.

5. slag as claimed in claim 4 and grey water treatment system, it is characterised in that traditional slag and grey water treatment system, Including：Three stages of flashing system, deaerating type of cycles, sedimentation clarification system；

The high pressure flash entrance of the three stages of flashing system is connected with the Heisui River output end of the hydraulic turbine system, the three-level The high pressure flash outlet of flash system connects the segmented evaporator high temperature section entrance of the organic rankine cycle system, described to have The segmented evaporator high temperature section outlet of machine Rankine cycle system connects the low pressure flash entrance of the three stages of flashing system, described The low pressure flash liquid outlet of three stages of flashing system connects the vacuum flashing entrance of the three stages of flashing system, the three stages of flashing system The low pressure flash gas outlet of system is connected with the deaerating type of cycles input；The vacuum flashing outlet connection of the three stages of flashing system The segmented evaporator low-temperature zone entrance of the organic rankine cycle system, the segmented evaporation of the organic rankine cycle system The outlet of device low-temperature zone takes back the three stages of flashing system；The final flashed liquid output end of the three stages of flashing system is sunk with described The aqueous water input connection of clarification system, the aqueous water output end and the liquid of the deaerating type of cycles of the sedimentation clarification system drop State water input connects, and the heating pipe entrance of the aqueous water output end of the deaerating type of cycles and the three stages of flashing system connects Connect, the heating pipe outlet of the three stages of flashing system is connected as process water output end with the hydraulic turbine system.

6. slag as claimed in claim 1 and grey water treatment system, it is characterised in that the gasification and synthesis gas washing system are defeated The Heisui River of the Heisui River output gone out includes：Gasification burner Heisui River, scrubbing tower Heisui River and cyclone separator Heisui River.