Two-effect energy-saving ammonia distillation system for kitchen waste anaerobic liquid

Abstract

The invention discloses a two-effect energy-saving ammonia distillation system for kitchen waste anaerobic liquid. The two-effect energy-saving ammonia distillation system comprises a first-effect heat exchanger, a first-effect ammonia distillation tower, a first-effect separation tank, a second-effect heater, a second-effect ammonia distillation tower, a second-effect heat exchanger, a second-effect separation tank, an ammonia recovery device, a cooler, an absorption ejector and a second-effect condenser, the first-effect heat exchanger is connected with the first-effect ammonia still and is used for heat exchange and feeding; a top outlet of the first-effect ammonia still is connected with the second-effect heater, the second-effect heater is connected with the first-effect separating tank, the first-effect separating tank is connected with the first-effect ammonia still, the second-effect heat exchanger is connected with the second-effect ammonia still, and outlets of the second-effect heater and the second-effect ammonia still converge and are jointly connected with the second-effect condenser. The second-effect condenser is connected with a second-effect separation tank, and the first-effect separation tank and the second-effect separation tank are connected with an absorption ejector at the same time. The problems that an existing ammonia still cannot effectively improve the production efficiency and cannot effectively guarantee reduction of energy consumption are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of restaurant garbage treatment, and in particular relates to a two-effect energy-saving ammonia distillation system for anaerobic liquid of restaurant garbage. Background Art

[0002] Anaerobic liquid from food waste is the treated liquid after anaerobic treatment of food waste, which has the characteristics of high SS, high alkalinity, high ammonia nitrogen, etc. The conventional treatment method is direct A / O or pre-treatment with ammonia evaporation followed by A / O. Due to the high ammonia nitrogen concentration and C / N imbalance in direct A / O treatment, a large amount of carbon source needs to be added, resulting in a long biochemical cycle, a large footprint, and it is difficult for the effluent ammonia nitrogen to meet the standard stably; pre-treatment with ammonia evaporation to reduce the ammonia nitrogen concentration and then A / O treatment does not require the addition of carbon source, and the biochemical cycle is greatly shortened, but the conventional single-effect ammonia evaporation tower consumes a lot of steam, and the investment and operation costs are high; in addition, due to the easy scaling of anaerobic liquid from food waste, the ammonia evaporation tower used for deammoniation of anaerobic liquid from food waste mostly adopts a plate structure, and its gas phase channel is mostly sieve holes or strip holes, and its diameter or width is mostly 5mm, which is very easy to scale and clog, and needs frequent cleaning.

[0003] Patent CN206188408U discloses a double-tower negative pressure deamination and ammonium bicarbonate recovery system. It includes a raw water pump, a preheater, an analysis tower, a deamination tower, a condenser, a hydraulic ejector, a purification device, a carbonization tower, a condensation coil, a circulation pump, a centrifuge, a gas-liquid separation tank, a reflux pump, a water outlet pump, and a material lifting pump. In this patent, the material first enters the analysis tower and then the deamination tower, and the steam first enters the deamination tower and then the analysis tower. Its essence is still a single-effect ammonia distillation tower in series, which does not effectively improve production efficiency and fails to effectively ensure energy consumption reduction. Summary of the invention

[0004] The invention proposes a two-effect energy-saving ammonia evaporation system for anaerobic liquid of kitchen waste, so as to solve the problem that the existing ammonia evaporation tower fails to effectively improve the production efficiency and fails to effectively ensure the reduction of energy consumption.

[0005] In order to realize the above scheme, the present invention discloses a two-effect energy-saving ammonia distillation system for anaerobic liquid of kitchen waste, comprising: a first-effect heat exchanger, a first-effect ammonia distillation tower, a first-effect separation tank, a second-effect heater, a second-effect ammonia distillation tower, a second-effect heat exchanger, a second-effect separation tank, an ammonia recovery device, a cooler, an absorption ejector and a second-effect condenser; the first-effect heat exchanger is connected with the first-effect ammonia distillation tower for heat exchange and feeding; the top outlet of the first-effect ammonia distillation tower is connected with the second-effect heater, the second-effect heater is connected with the first-effect separation tank, the first-effect separation tank is connected with the first-effect ammonia distillation tower, the second-effect heat exchanger is connected with the second-effect ammonia distillation tower, the second-effect heater and the outlet of the second-effect ammonia distillation tower are collected and connected with the second-effect condenser together, the second-effect condenser is connected with the second-effect separation tank, the first-effect separation tank and the second-effect separation tank are simultaneously connected with the absorption ejector, and the absorption ejector is connected with the cooler and the second-effect condenser.

[0006] An application of a two-effect energy-saving ammonia distillation system based on anaerobic liquid from kitchen waste, comprising:

[0007] The anaerobic liquid is divided into two streams. The first stream of anaerobic liquid enters the first-effect heat exchanger and exchanges heat with the bottom outlet water of the first-effect ammonia evaporation tower to 55-60°C, then enters the top feed port of the first-effect ammonia evaporation tower, moves from top to bottom through the packing surface in the first-effect ammonia evaporation tower, and fully transfers mass and heat with the fresh saturated steam moving from bottom to top in the first-effect ammonia evaporation tower, so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase and can be discharged from the top of the first-effect ammonia evaporation tower;

[0008] The second stream of anaerobic liquid enters the second-effect heat exchanger and exchanges heat with the bottom outlet water of the second-effect ammonia evaporation tower to 45-50°C, then enters the top feed port of the second-effect ammonia evaporation tower, moves from top to bottom through the packing surface in the second-effect ammonia evaporation tower, and fully transfers mass and heat with the secondary steam moving from bottom to top in the second-effect ammonia evaporation tower, so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase and escapes from the top of the second-effect ammonia evaporation tower;

[0009] The ammonia-containing steam from the top of the first-effect ammonia distillation tower enters the second-effect heater as a heat source to heat the deammoniation water at the bottom of the second-effect ammonia distillation tower to generate secondary steam;

[0010] The secondary steam condensate containing ammonia in the second-effect heater enters the first-effect separation tank, and is then pumped to the top reflux port of the first-effect ammonia distillation tower;

[0011] The non-condensable gas in the second-effect heater is merged into the vapor phase pipeline at the top of the second-effect ammonia distillation tower. The ammonia-containing secondary steam at the top of the second-effect ammonia distillation tower enters the second-effect condenser and enters the second-effect separation tank after condensation.

[0012] The non-condensable ammonia gas in the first-effect separation tank is merged into the ammonia gas pipeline before the absorption ejector;

[0013] The condensate in the second-effect separation tank is pumped to the reflux port at the top of the second-effect ammonia distillation tower, and the ammonia in the second-effect separation tank is merged into the front ammonia pipeline of the absorption ejector;

[0014] The recovered liquid in the ammonia recovery device is pumped to the cooler and then enters the absorption ejector, and then enters the ammonia recovery device to form an absorption cycle.

[0015] As a further improvement of the above technical solution:

[0016] The top pressure of the first-effect ammonia distillation tower is -0.045MPa to -0.05MPa, the temperature is 80-85°C, and the bottom pressure is -0.035MPa to -0.040MPa, the temperature is 85-90°C.

[0017] The top pressure of the second-effect ammonia distillation tower is -0.075MPa to -0.080MPa, the temperature is 60-65°C, and the bottom pressure is -0.065MPa to -0.070MPa, the temperature is 65-70°C.

[0018] The pressure in the first-effect separation tank is -0.050MPa to -0.055MPa, and the temperature is 67-72°C.

[0019] The pressure in the second-effect separation tank is -0.080MPa to -0.085MPa, and the temperature is 35-40°C.

[0020] The ammonia recovery device is at normal pressure and temperature of 35-40°C.

[0021] The first-effect ammonia distillation tower and the second-effect ammonia distillation tower are both filler structures, using high-temperature resistant PTFE fillers with an operating temperature of -200°C to 260°C, a thermal deformation temperature of 130-140°C, a water absorption rate of <0.01%, and a Rockwell hardness of HRD50-60.

[0022] The first-effect heat exchanger and the second-effect heat exchanger are both wide-channel plate heat exchangers, with a channel width of 20 mm and a plate thickness of 2 mm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Significant energy-saving effect: By adopting a two-effect ammonia evaporation tower, the secondary steam of the first-effect ammonia evaporation tower is used as the heat source of the second-effect ammonia evaporation tower, which effectively reduces the steam consumption. Compared with the single-effect ammonia evaporation tower, the steam consumption can be reduced by 50%, greatly improving the energy utilization efficiency.

[0025] Reduced investment cost: The design of the two-effect ammonia evaporation tower greatly reduces the size of the equipment such as the ammonia evaporation tower and the second-effect condenser, thereby reducing the manufacturing cost and floor space of the equipment and reducing the investment cost.

[0026] Stable equipment operation: The application of new high-temperature resistant PTFE filler avoids narrow gas phase channels, reduces scaling, and improves the operating stability and service life of the equipment.

[0027] Good environmental benefits: The system adopts reduced-pressure ammonia evaporation technology, which reduces ammonia nitrogen emissions and is beneficial to environmental protection.

[0028] The water-saving effect is obvious: by recycling the condensate, the consumption of fresh water is reduced and the efficient use of water resources is achieved.

[0029] Small footprint: As the equipment size is reduced, the footprint is correspondingly reduced, which is conducive to saving land resources.

[0030] Strong adaptability: The system can adapt to the anaerobic liquid treatment needs of food waste of different scales and has strong adaptability.

[0031] Safe and reliable: The system adopts negative pressure operation, which reduces the safety risks during operation and improves the safety of the system.

[0032] Significant economic benefits: The overall economic benefits are improved by saving energy and reducing consumption, investment costs and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the test tube of the present invention when installed.

[0034] Figure numerals: 1. first-effect heat exchanger; 2. first-effect ammonia evaporation tower; 3. first-effect separation tank; 4. second-effect heater; 5. second-effect ammonia evaporation tower; 6. second-effect heat exchanger; 7. second-effect separation tank; 8. ammonia recovery device; 9. cooler; 10. absorption ejector; 11. second-effect condenser. DETAILED DESCRIPTION

[0035] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0036] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] like Figure 1 As shown, the two-effect energy-saving ammonia distillation system for anaerobic liquid of kitchen waste in this embodiment comprises: a first-effect heat exchanger 1, a first-effect ammonia distillation tower 2, a first-effect separation tank 3, a second-effect heater 4, a second-effect ammonia distillation tower 5, a second-effect heat exchanger 6, a second-effect separation tank 7, an ammonia recovery device 8, a cooler 9, an absorption ejector 10 and a second-effect condenser 11; the first-effect heat exchanger 1 is connected to the first-effect ammonia distillation tower 2 for heat exchange and feeding; the top outlet of the first-effect ammonia distillation tower 2 is connected to the second-effect heater 4, the second-effect heater 4 is connected to the first-effect separation tank 3, the first-effect separation tank 3 is connected to the first-effect ammonia distillation tower 2, the second-effect heat exchanger 6 is connected to the second-effect ammonia distillation tower 5, the outlets of the second-effect heater 4 and the second-effect ammonia distillation tower 5 are collected and connected to the second-effect condenser 11, the second-effect condenser 11 is connected to the second-effect separation tank 7, the first-effect separation tank 3 and the second-effect separation tank 7 are simultaneously connected to the absorption ejector 10, and the absorption ejector 10 is connected to the cooler 9 and the second-effect condenser 11.

[0040] The invention uses the decompression effect of the two-effect ammonia evaporation tower and the secondary steam of the first-effect ammonia evaporation tower as the heat source of the second-effect ammonia evaporation tower, thereby reducing the steam consumption by 50% compared with the single-effect ammonia evaporation tower. The two-effect ammonia evaporation tower can greatly reduce the size specifications of the equipment such as the ammonia evaporation tower and the second-effect condenser, thereby greatly reducing the investment cost. The two-effect ammonia evaporation towers both use new high-temperature resistant PTFE fillers, thereby avoiding narrow gas phase channels and solving the problem of scaling substances adhering to the wall of metal materials, thereby preventing scaling.

[0041] The application of the two-effect energy-saving ammonia distillation system of anaerobic liquid from kitchen waste according to claim 1 in this embodiment includes:

[0042] The anaerobic liquid is divided into two streams. The first stream of anaerobic liquid enters the first-effect heat exchanger 1 and exchanges heat with the bottom outlet water of the first-effect ammonia distillation tower 2 to 55-60°C, and then enters the top feed port of the first-effect ammonia distillation tower 2. The first stream of anaerobic liquid moves from top to bottom through the surface of the packing in the first-effect ammonia distillation tower 2, and fully transfers mass and heat with the fresh saturated steam moving from bottom to top in the first-effect ammonia distillation tower 2, so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase and can be discharged from the top of the first-effect ammonia distillation tower 2.

[0043] The second stream of anaerobic liquid enters the second-effect heat exchanger 6 and exchanges heat with the bottom outlet water of the second-effect ammonia distillation tower 5 to 45-50°C, then enters the top feed port of the second-effect ammonia distillation tower 5, moves from top to bottom through the packing surface in the second-effect ammonia distillation tower 5, and fully transfers mass and heat with the secondary steam moving from bottom to top in the second-effect ammonia distillation tower 5, so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase and escapes from the top of the second-effect ammonia distillation tower 5;

[0044] The ammonia-containing steam from the top of the first-effect ammonia evaporation tower 2 enters the second-effect heater 4 as a heat source to heat the deammoniation water at the bottom of the second-effect ammonia evaporation tower 5 to generate secondary steam;

[0045] The ammonia secondary steam condensate in the second-effect heater 4 enters the first-effect separation tank 3, and is then pumped to the top reflux port of the first-effect ammonia distillation tower 2;

[0046] The non-condensable gas in the second-effect heater 4 is merged into the top vapor phase pipeline of the second-effect ammonia distillation tower 5, and the ammonia-containing secondary steam at the top of the second-effect ammonia distillation tower 5 enters the second-effect condenser 11, and enters the second-effect separation tank 7 after condensation;

[0047] The non-condensable ammonia gas in the first-effect separation tank 3 is merged into the front ammonia gas pipeline of the absorption ejector 10;

[0048] The condensate in the second-effect separation tank 7 is pumped to the top reflux port of the second-effect ammonia distillation tower 5, and the ammonia in the second-effect separation tank 7 is merged into the front ammonia pipeline of the absorption ejector 10;

[0049] The recovered liquid in the ammonia recovery device 8 is pumped to the cooler 9 and then enters the absorption ejector 10, and then enters the ammonia recovery device 8 to form an absorption cycle.

[0050] The top pressure of the first-effect ammonia distillation tower 2 is -0.045MPa to -0.05MPa, the temperature is 80-85°C, and the bottom pressure is -0.035MPa to -0.040MPa, the temperature is 85-90°C.

[0051] The top pressure of the second-effect ammonia distillation tower 5 is -0.075MPa to -0.080MPa, the temperature is 60-65°C, and the bottom pressure is -0.065MPa to -0.070MPa, the temperature is 65-70°C.

[0052] The pressure in the first-effect separation tank 3 is -0.050MPa to -0.055MPa, and the temperature is 67-72°C.

[0053] The pressure in the second-effect separation tank 7 is -0.080MPa to -0.085MPa, and the temperature is 35-40°C.

[0054] The inside of the ammonia recovery device 8 is at normal pressure and the temperature is 35-40°C.

[0055] The first-effect ammonia distillation tower 2 and the second-effect ammonia distillation tower 5 are both packing structures, using high-temperature resistant PTFE packing, with an operating temperature of -200°C to 260°C, a thermal deformation temperature of 130-140°C, a water absorption rate of <0.01%, and a Rockwell hardness of HRD50-60.

[0056] The first-effect heat exchanger 1 and the second-effect heat exchanger 6 are both wide-channel plate heat exchangers, with a channel width of 20 mm and a plate thickness of 2 mm.

[0057] Specific examples:

[0058] The original single-effect ammonia distillation system with a processing capacity of 20t / h adopts a tray structure. Two sets of ammonia evaporation towers, condenser heat exchange area 160㎡, steam consumption 2-2.4t / h, cleaning cycle 7-15d; adopt the two-effect energy-saving ammonia evaporation system of this embodiment, one-effect ammonia evaporation tower Second effect ammonia distillation tower The heat exchange area of ​​the second-effect condenser is 80㎡, the steam consumption is 1-1.2t / h, and the cleaning cycle is 4-6 months; when the ammonia nitrogen in the inlet water is about 3000mg / L, the ammonia nitrogen in the outlet water is below 100mg / L.

[0059] The above is only an embodiment of the present invention, and the common sense such as the known specific structure and characteristics in the scheme is not described in detail here. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

Claims

1. A two-effect energy-saving ammonia distillation system for anaerobic liquid from kitchen waste, characterized in that: include: A first-effect heat exchanger (1), a first-effect ammonia evaporation tower (2), a first-effect separation tank (3), a second-effect heater (4), a second-effect ammonia evaporation tower (5), a second-effect heat exchanger (6), a second-effect separation tank (7), an ammonia recovery device (8), a cooler (9), an absorption ejector (10) and a second-effect condenser (11); the first-effect heat exchanger (1) is connected to the first-effect ammonia evaporation tower (2) for heat exchange and feeding; the top outlet of the first-effect ammonia evaporation tower (2) is connected to the second-effect heater (4), and the second-effect heater (4) is connected to the first-effect separation tank (3 ), the first-effect separation tank (3) is connected to the first-effect ammonia evaporation tower (2), the second-effect heat exchanger (6) is connected to the second-effect ammonia evaporation tower (5), the second-effect heater (4) and the second-effect ammonia evaporation tower (5) are connected together and connected to a second-effect condenser (11), the second-effect condenser (11) is connected to the second-effect separation tank (7), the first-effect separation tank (3) and the second-effect separation tank (7) are simultaneously connected to an absorption ejector (10), and the absorption ejector (10) is connected to a cooler (9) and a second-effect condenser (11).

2. An application of a two-effect energy-saving ammonia distillation system based on the anaerobic liquid of kitchen waste according to claim 1, characterized in that: include: The anaerobic liquid is divided into two streams. The first stream of anaerobic liquid enters the first-effect heat exchanger (1) and exchanges heat with the bottom outlet water of the first-effect ammonia evaporation tower (2) to 55-60° C., and then enters the top feed port of the first-effect ammonia evaporation tower (2). The first stream of anaerobic liquid moves from top to bottom through the surface of the packing in the first-effect ammonia evaporation tower (2), and fully transfers mass and heat with the fresh saturated steam moving from bottom to top in the first-effect ammonia evaporation tower (2), so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase, and is discharged from the top of the first-effect ammonia evaporation tower (2). The second stream of anaerobic liquid enters the second-effect heat exchanger (6) and exchanges heat with the bottom outlet water of the second-effect ammonia evaporation tower (5) to 45-50°C, then enters the top feed port of the second-effect ammonia evaporation tower (5), moves from top to bottom through the surface of the packing in the second-effect ammonia evaporation tower (5), and fully transfers mass and heat with the secondary steam moving from bottom to top in the second-effect ammonia evaporation tower (5), so that the ammonia nitrogen in the anaerobic liquid is transferred to the vapor phase and discharged from the top of the second-effect ammonia evaporation tower (5); Ammonia-containing steam discharged from the top of the first-effect ammonia evaporation tower (2) enters the second-effect heater (4) and serves as a heat source to heat the deammoniation water at the bottom of the second-effect ammonia evaporation tower (5) to generate secondary steam; The ammonia secondary steam condensate in the second-effect heater (4) enters the first-effect separation tank (3), and is then pumped to the top reflux port of the first-effect ammonia distillation tower (2); The non-condensable gas in the second-effect heater (4) is introduced into the vapor phase pipeline at the top of the second-effect ammonia distillation tower (5), and the ammonia-containing secondary steam at the top of the second-effect ammonia distillation tower (5) enters the second-effect condenser (11), and enters the second-effect separation tank (7) after condensation; The non-condensable ammonia gas in the first-effect separation tank (3) is introduced into the front ammonia gas pipeline of the absorption ejector (10); The condensate in the second-effect separation tank (7) is pumped to the top reflux port of the second-effect ammonia distillation tower (5), and the ammonia in the second-effect separation tank (7) is introduced into the front ammonia pipeline of the absorption ejector (10); The recovered liquid in the ammonia recovery device (8) is pumped to the cooler (9) and then enters the absorption ejector (10), and then enters the ammonia recovery device (8), forming an absorption cycle.

3. The use according to claim 2, characterized in that: The first-effect ammonia distillation tower (2) has a top pressure of -0.045 MPa to -0.05 MPa and a temperature of 80-85°C, and a bottom pressure of -0.035 MPa to -0.040 MPa and a temperature of 85-90°C.

4. The use according to claim 2, characterized in that: The second-effect ammonia distillation tower (5) has a top pressure of -0.075 MPa to -0.080 MPa and a temperature of 60-65°C, and a bottom pressure of -0.065 MPa to -0.070 MPa and a temperature of 65-70°C.

5. The use according to claim 2, characterized in that: The pressure in the first-effect separation tank (3) is -0.050 MPa to -0.055 MPa, and the temperature is 67-72°C.

6. The use according to claim 2, characterized in that: The pressure in the second-effect separation tank (7) is -0.080 MPa to -0.085 MPa, and the temperature is 35-40°C.

7. The use according to claim 2, characterized in that: The ammonia recovery device (8) is at normal pressure and at a temperature of 35-40°C.

8. The use according to claim 2, characterized in that: The first-effect ammonia distillation tower (2) and the second-effect ammonia distillation tower (5) are both filler structures, using high-temperature resistant PTFE fillers, with an operating temperature of -200°C to 260°C, a thermal deformation temperature of 130-140°C, a water absorption rate of less than 0.01%, and a Rockwell hardness of HRD50-60.

9. The use according to claim 2, characterized in that: The first-effect heat exchanger (1) and the second-effect heat exchanger (6) are both wide-channel plate heat exchangers, with a channel width of 20 mm and a plate thickness of 2 mm.

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