A device and method for utilizing waste incineration waste heat for combined cooling and power generation

Abstract

The present invention provides a waste incineration waste heat utilization device and method for combined cooling and power generation, including a waste incinerator, wherein the waste incinerator is provided with a municipal domestic waste inlet and an air inlet; the waste incinerator is provided with a high-temperature flue gas outlet and a high-temperature slag outlet, wherein the high-temperature slag outlet and the high-temperature flue gas outlet are both connected to a steam Rankine cycle system; the low-temperature gas outlet of the steam Rankine cycle system is connected to the gas inlet of an organic Rankine cycle system; the organic Rankine cycle system is provided with a low-temperature gas outlet and a circulating water outlet, and the low-temperature gas outlet is connected to a refrigeration device; the circulating water outlet is connected to the circulating water inlet of the steam Rankine cycle system; the present invention recovers the heat in the slag and flue gas at the bottom of the incinerator of a waste incineration power plant through a multi-stage heat recovery unit, and then generates electricity through the steam Rankine cycle system and the organic Rankine cycle system, thereby increasing the output power of the waste incineration power plant; then, the heat of the low-temperature flue gas generated by the organic Rankine cycle system is used to drive the refrigeration machine to extract cold energy, thereby realizing combined cooling and power generation and providing cooling income for the power plant.

Description

Technical Field

[0001] The present invention belongs to the field of waste incineration power generation, and in particular relates to a waste incineration waste heat utilization device and method for combined cooling and power generation. Background Art

[0002] In the long run, the leachate generated during the landfill process is difficult to treat and will cause pollution to the land and groundwater resources in the area. With the advancement of urbanization, the pressure on landfills is increasing.

[0003] Waste incineration power generation is to release the chemical energy stored in domestic waste through incineration, convert it into heat energy and use it. Compared with landfill, the pollutant gas emissions generated by waste incineration are much lower. At the same time, the electricity and heat generated can also reduce the consumption of non-renewable energy, achieve energy conservation and emission reduction, and is gradually becoming the mainstream of urban domestic waste treatment in my country.

[0004] Although incineration has significant advantages in the harmless treatment of urban domestic waste, there are also some key issues to be resolved. The most widespread problem is that the overall energy efficiency of waste incineration power plants is low, and there is a large loss of low-grade energy, mainly due to the heat loss of boiler combustion and the low-temperature heat loss of exhaust gas. In addition, the bottom ash particles at the bottom of the incinerator of the waste incineration power plant also contain a large amount of waste heat energy, but the current waste incineration power plants rarely use this part of heat. Summary of the invention

[0005] The purpose of the present invention is to provide a waste incineration waste heat utilization device and method for combined cooling and power generation, which solves the defect that the prior art does not utilize the heat in the slag at the bottom of the incinerator of the waste incineration power plant, but only utilizes the waste heat in the flue gas.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a waste incineration waste heat utilization device for combined cooling and power generation, comprising a waste incinerator, wherein the waste incinerator is provided with a municipal domestic waste inlet and an air inlet; the waste incinerator is provided with a high-temperature flue gas outlet and a high-temperature slag outlet, wherein the high-temperature slag outlet and the high-temperature flue gas outlet are both connected to a steam Rankine cycle system;

[0008] The low-temperature gas outlet of the steam Rankine cycle system is connected to the gas inlet of the organic Rankine cycle system; the organic Rankine cycle system is provided with a low-temperature gas outlet and a circulating water outlet, the low-temperature gas outlet is connected to a refrigeration device; the circulating water outlet is connected to the circulating water inlet of the steam Rankine cycle system.

[0009] Preferably, the steam Rankine cycle system comprises a slag waste heat boiler, a flue gas waste heat boiler, a first steam turbine and a third steam turbine, wherein the high-temperature slag outlet is connected to a slag inlet provided on the slag waste heat boiler, and the superheated steam outlet provided on the slag waste heat boiler is connected to a steam inlet of the first steam turbine;

[0010] The high-temperature flue gas outlet is connected to the flue gas inlet provided on the flue gas waste heat boiler, and the superheated steam outlet provided on the flue gas waste heat boiler is connected to the steam inlet of the third steam turbine;

[0011] The exhaust steam outlet provided on the first steam turbine and the low-temperature flue gas outlet provided on the flue gas waste heat boiler are connected to an organic Rankine cycle system;

[0012] The circulating water inlet arranged on the slag waste heat boiler is connected to the circulating water outlet of the organic Rankine cycle system.

[0013] Preferably, a second condenser is provided between the circulating water inlet of the slag waste heat boiler and the circulating water outlet of the organic Rankine cycle system.

[0014] Preferably, the exhaust steam outlet on the third steam turbine is connected to the exhaust steam inlet of the first condenser, and the condensed water outlet provided on the first condenser is connected to the circulating water inlet provided on the flue gas waste heat boiler.

[0015] Preferably, the organic Rankine cycle system includes a first heat exchanger, a second heat exchanger and a second steam turbine, wherein the gas inlet on the first heat exchanger and the gas inlet on the second heat exchanger are both connected to the gas outlet set on the steam Rankine cycle system; the organic working fluid outlet set on the first heat exchanger is connected to the organic working fluid inlet set on the second heat exchanger; the superheated steam outlet set on the second heat exchanger is connected to the steam inlet set on the second steam turbine, and the exhaust steam outlet set on the second steam turbine is connected to the organic working fluid inlet of the first heat exchanger through a third condenser.

[0016] Preferably, the low-temperature gas outlet on the first heat exchanger is connected to a circulating water inlet provided on the steam Rankine cycle system through a second condenser.

[0017] Preferably, the low-temperature gas outlet provided on the second heat exchanger is connected to a refrigeration device.

[0018] Preferably, the refrigeration equipment comprises a refrigerator, and the refrigerator is provided with a flue gas inlet, wherein the flue gas inlet is connected to a low-temperature flue gas outlet of the organic Rankine cycle system, and the refrigerator is provided with a cold water outlet.

[0019] A method for utilizing waste incineration waste heat for combined cooling and power generation, comprising the following steps:

[0020] Municipal domestic waste enters the waste incinerator and is burned with the help of air, producing high-temperature slag and high-temperature flue gas;

[0021] The obtained high-temperature flue gas and high-temperature slag are used to generate electricity using a steam Rankine cycle system;

[0022] The low temperature gas produced by the steam Rankine cycle system is used to generate electricity using the organic Rankine cycle system;

[0023] The low-temperature flue gas generated by the organic Rankine cycle is used to cool the cooling return water.

[0024] Preferably, the high-temperature slag enters the slag waste heat boiler to exchange heat with the circulating water. The circulating water receives the heat from the high-temperature slag and is heated to form superheated steam, which is sent to the first steam turbine to generate power. The exhaust steam after the power generation enters the first heat exchanger to exchange heat with the circulating organic working medium, and then enters the second condenser to condense into water and return to the slag waste heat boiler, completing the steam Rankine cycle.

[0025] The circulating organic working medium is heated up after heat exchange with exhaust steam in the first heat exchanger, and then enters the second heat exchanger to exchange heat with the cooled flue gas and exhaust gas to evaporate into steam, and then enters the second steam turbine to generate power. The organic working medium steam after work is condensed into liquid through the third condenser, completing the organic Rankine cycle.

[0026] The flue gas exhaust from the incinerator enters the flue gas waste heat boiler to exchange heat with the circulating water for cooling, then enters the second heat exchanger to exchange heat with the organic working fluid, and then enters the refrigerator to drive the refrigeration mechanism to extract cooling capacity;

[0027] The circulating water generates superheated steam in the flue gas waste heat boiler, enters the third steam turbine to generate power, and the exhaust steam enters the first condenser to condense into water and then returns to the flue gas waste heat boiler to complete the cycle.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The invention provides a waste incineration waste heat utilization device for combined cooling and power generation. Through multi-stage heat recovery, the heat in the slag and flue gas at the bottom of the incinerator of the waste incineration power plant is simultaneously recovered and utilized, and power is generated through steam Rankine cycle and organic Rankine cycle, thereby increasing the output power of the waste incineration power plant. The heat of the low-temperature flue gas is used to drive the refrigerator to extract cold energy, realize combined cooling and power generation, and provide cooling income for the power plant.

[0030] Furthermore, the output power and energy utilization efficiency of the waste incineration power plant are improved through the cascade recovery of flue gas and slag heat and the matching and coupling between heat of different grades;

[0031] Furthermore, by using waste heat boilers to recover slag heat for steam Rankine cycle power generation, the cooling water consumption in the conventional slag treatment process is greatly reduced.

[0032] Furthermore, by using low-temperature flue gas to drive a refrigeration mechanism to extract cold energy, combined cooling and electricity generation can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a system structure diagram involved in the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0035] like Figure 1 As shown, a waste incineration waste heat utilization device for combined cooling and power generation provided by the present invention comprises a waste incinerator 1, a slag waste heat boiler 2, a first steam turbine 3, a second steam turbine 4, a third steam turbine 5, a flue gas waste heat boiler 6, a first condenser 7, a first heater 8, a second heater 9, a second condenser 10, a refrigerator 11 and a third condenser 12, wherein the waste incinerator 1 is provided with a waste inlet, an air inlet, a high-temperature flue gas outlet and a high-temperature slag outlet, wherein the high-temperature flue gas outlet is connected to the flue gas inlet of the flue gas waste heat boiler 6, and the superheated steam outlet arranged on the flue gas waste heat boiler 6 is connected to the flue gas inlet of the third steam turbine 5.

[0036] The exhaust steam outlet on the third steam turbine 5 is connected to the inlet of the first condenser 7 , and the condensed water outlet of the first condenser 7 is connected to the circulating water inlet provided on the flue gas waste heat boiler 6 .

[0037] The flue gas waste heat boiler 6 is provided with a flue gas outlet connected to the flue gas inlet of the second heater 9 , and the low-temperature flue gas outlet provided on the second heater 9 is connected to the flue gas inlet of the refrigerator 11 .

[0038] The high-temperature slag outlet is connected to the slag inlet of the slag waste heat boiler 2, the superheated steam outlet arranged on the slag waste heat boiler 2 is connected to the steam inlet of the first steam turbine 3, the exhaust steam outlet on the first steam turbine 3 is connected to the gas inlet of the first heat exchanger 8, and the organic working fluid outlet of the first heat exchanger 8 is connected to the organic working fluid inlet of the second heat exchanger 9.

[0039] The superheated steam outlet of the second heat exchanger 9 is connected to the steam inlet of the second steam turbine 4 , the exhaust steam outlet of the second steam turbine 4 is connected to the inlet of the third condenser 12 , and the condensed water outlet of the third condenser 12 is connected to the circulating water inlet of the first heat exchanger 8 .

[0040] The circulating water outlet arranged on the first heat exchanger 8 is connected to the inlet of the second condenser 10 , and the circulating water outlet of the second condenser 10 is connected to the circulating water inlet of the slag waste heat boiler 2 .

[0041] The refrigerator 11 is provided with a cooling return water inlet and a cooling water outlet.

[0042] Working process of the present invention:

[0043] Urban domestic waste 13 enters the waste incinerator 1 and is burned with the assistance of air 14 to produce high-temperature slag 16 and high-temperature flue gas 15 .

[0044] The high-temperature slag 16 from the bottom of the incinerator of the waste incineration power plant enters the slag waste heat boiler 2 to exchange heat with the circulating water, and the solid particles are discharged after being cooled.

[0045] The circulating water absorbs the heat from the slag to become superheated steam, which is sent to the first steam turbine 3 to generate power. The exhaust steam after the work enters the first heat exchanger 8 to exchange heat with the circulating organic working medium, and then enters the second condenser 10 to condense into water and return to the slag waste heat boiler 2, completing the steam Rankine cycle.

[0046] The circulating organic working medium exchanges heat with steam in the first heat exchanger 8 and enters the second heat exchanger 9 to exchange heat with the cooled flue gas and exhaust gas to evaporate into steam, and then enters the second steam turbine 4 to generate power. The organic working medium steam after work is condensed into liquid through the third condenser 12, completing the organic Rankine cycle.

[0047] The flue gas exhaust 15 discharged from the incinerator enters the flue gas waste heat boiler 6 to exchange heat with the circulating water for cooling, then enters the second heat exchanger 9 to exchange heat with the organic working medium, then enters the refrigerator 11 to drive cooling and then goes to the purification device.

[0048] The circulating water is heated in the flue gas waste heat boiler 6 to generate superheated steam, which enters the third steam turbine 5 to generate power. The exhaust steam enters the first condenser 7 to condense into water and then returns to the flue gas waste heat boiler 6 to complete the cycle.

[0049] The cooling return water 17 enters the refrigerator 11 and extracts cold energy under the action of the low-temperature flue gas for cooling.

[0050] The present invention simultaneously recycles the heat in the slag and flue gas at the bottom of the incinerator of the waste incineration power plant through multi-stage heat recovery, generates electricity through steam Rankine cycle and organic Rankine cycle, and improves the output power of the waste incineration power plant. The heat of low-temperature flue gas is used to drive the refrigerator to extract cold energy, realize combined cooling and power supply, and provide cooling income for the power plant.

[0051] 1. The output power and energy utilization efficiency of the waste incineration power plant are improved through the cascade recovery of flue gas and slag heat and the matching and coupling between heat of different grades;

[0052] 2. By using waste heat boilers to recover slag heat for steam Rankine cycle power generation, the cooling water consumption in the conventional slag treatment process is greatly reduced.

[0053] 3. Use low-temperature flue gas to drive the refrigeration mechanism to extract cold energy and achieve combined cooling and electricity.

[0054] The output power and energy efficiency of the waste incineration power plant are improved by the cascade recovery of flue gas and slag heat and the matching and coupling of heat of different grades; the consumption of cooling water in the conventional slag treatment process is greatly reduced by using waste heat boiler to recover slag heat for steam Rankine cycle power generation. By using low-temperature flue gas to drive the refrigeration mechanism to extract cold energy, a certain amount of cold is provided for the power plant, realizing the combined supply of cooling and electricity.

Claims

1. A waste incineration waste heat utilization device for combined cooling and power generation, characterized in that: The invention comprises a waste incinerator (1), wherein the waste incinerator (1) is provided with a municipal waste inlet and an air inlet; the waste incinerator (1) is provided with a high-temperature flue gas outlet and a high-temperature slag outlet, wherein the high-temperature slag outlet and the high-temperature flue gas outlet are both connected to a steam Rankine cycle system; The low-temperature gas outlet provided on the steam Rankine cycle system is connected to the gas inlet of the organic Rankine cycle system; the organic Rankine cycle system is provided with a low-temperature gas outlet and a circulating water outlet, the low-temperature gas outlet is connected to a refrigeration device; the circulating water outlet is connected to the circulating water inlet of the steam Rankine cycle system; The steam Rankine cycle system comprises a slag waste heat boiler (2), a flue gas waste heat boiler (6), a first steam turbine (3) and a third steam turbine (5), wherein the high-temperature slag outlet is connected to a slag inlet provided on the slag waste heat boiler (2), and the superheated steam outlet provided on the slag waste heat boiler (2) is connected to a steam inlet of the first steam turbine (3); The high-temperature flue gas outlet is connected to a flue gas inlet provided on a flue gas waste heat boiler (6), and the superheated steam outlet provided on the flue gas waste heat boiler (6) is connected to a steam inlet of a third steam turbine (5); The exhaust steam outlet provided on the first steam turbine (3) and the low-temperature flue gas outlet provided on the flue gas waste heat boiler (6) are connected to an organic Rankine cycle system; The circulating water inlet of the slag waste heat boiler (2) is connected to the circulating water outlet of the organic Rankine cycle system; The organic Rankine cycle system comprises a first heat exchanger (8), a second heat exchanger (9) and a second steam turbine (4), wherein the gas inlet on the first heat exchanger (8) and the gas inlet on the second heat exchanger (9) are both connected to a gas outlet provided on the steam Rankine cycle system; the organic working medium outlet provided on the first heat exchanger (8) is connected to an organic working medium inlet provided on the second heat exchanger (9); the superheated steam outlet provided on the second heat exchanger (9) is connected to a steam inlet provided on the second steam turbine (4), and the exhaust steam outlet provided on the second steam turbine (4) is connected to the organic working medium inlet of the first heat exchanger (8) through a third condenser (12); and the low-temperature gas outlet on the first heat exchanger (8) is connected to a circulating water inlet provided on the steam Rankine cycle system through a second condenser (10).

2. The waste incineration waste heat utilization device for combined cooling and power generation according to claim 1 is characterized in that: A second condenser (10) is provided between the circulating water inlet on the slag waste heat boiler (2) and the circulating water outlet of the organic Rankine cycle system.

3. The waste incineration waste heat utilization device for combined cooling and power generation according to claim 1 is characterized in that: The exhaust steam outlet on the third steam turbine (5) is connected to the exhaust steam inlet of the first condenser (7), and the condensed water outlet provided on the first condenser (7) is connected to the circulating water inlet provided on the flue gas waste heat boiler (6).

4. The waste incineration waste heat utilization device for combined cooling and power generation according to claim 1 is characterized in that: The low-temperature gas outlet provided on the second heat exchanger (9) is connected to a refrigeration device.

5. The waste incineration waste heat utilization device for combined cooling and power generation according to claim 1 is characterized in that: The refrigeration equipment comprises a refrigerator (11), the refrigerator (11) being provided with a smoke inlet, wherein the smoke inlet is connected to a low-temperature smoke outlet of an organic Rankine cycle system, and the refrigerator (11) is provided with a cold water outlet.

6. A method for utilizing waste incineration waste heat for combined cooling and power generation, characterized in that: The following steps are involved: Municipal domestic waste (13) enters a waste incinerator (1) and is burned with the aid of air (14), producing high-temperature slag (16) and high-temperature flue gas (15); The obtained high-temperature flue gas (15) and high-temperature slag (16) are used to generate electricity using a steam Rankine cycle system; The low temperature gas produced by the steam Rankine cycle system is used to generate electricity using the organic Rankine cycle system; The low-temperature flue gas generated by the organic Rankine cycle is used to cool the cooling return water; The high-temperature slag (16) enters the slag waste heat boiler (2) to exchange heat with the circulating water. The circulating water receives the heat from the high-temperature slag (16) and is heated to form superheated steam, which is then sent to the first steam turbine (3) to generate power. The exhaust steam after the power generation enters the first heat exchanger (8) to exchange heat with the circulating organic working medium, and then enters the second condenser (10) to be condensed into water and returned to the slag waste heat boiler (2), thus completing the steam Rankine cycle. The circulating organic working medium is heated up after heat exchange with exhaust steam in the first heat exchanger (8), then enters the second heat exchanger (9) to exchange heat with the flue gas and exhaust gas after the temperature has been reduced to evaporate into steam, and then enters the second steam turbine (4) to generate power. The organic working medium steam after the work is condensed into liquid through the third condenser (12), completing the organic Rankine cycle; The flue gas exhaust from the incinerator enters the flue gas waste heat boiler (6) to exchange heat with circulating water for cooling, then enters the second heat exchanger (9) to exchange heat with the organic working fluid, and then enters the refrigerator (11) to drive the refrigerator to extract cooling capacity; The circulating water generates superheated steam in the flue gas waste heat boiler (6), enters the third steam turbine (5) to generate power, and the exhaust steam enters the first condenser (7) to be condensed into water, and then returns to the flue gas waste heat boiler (6) to complete the cycle.

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