Steam double-effect type lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation function

Abstract

The utility model relates to a steam double-effect type lithium bromide absorption refrigeration heat pump unit with a condensate flash evaporation function, which comprises a low-pressure generator, a high-pressure generator, a condenser, a high-temperature heat exchanger, a low-temperature heat exchanger, an absorber, an evaporator, a solution pump, a refrigerant pump and a condensate flash evaporation tank. Flash steam generated by flash evaporation of steam condensate in the condensate flash tank enters a low-pressure generator for heat release and condensation, the condensate returns to the condensate flash tank again or directly flows out of the unit, and the steam condensate in the condensate flash tank flows out of the unit automatically, or the condensate flash tank is provided with a condensate delivery pump. And steam condensate water in the condensate water flash tank is conveyed out through a condensate water conveying pump. According to the unit, under the condition that heat exchange and cooling of a concentrated solution in the low-temperature heat exchanger are not affected, the temperature of driving steam condensate is reduced as much as possible to recycle heat in driving steam.

Description

Technical Field

[0001] The utility model relates to the technical field of air-conditioning equipment, in particular to a steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation. Background Art

[0002] Conventional steam double-effect lithium bromide absorption refrigeration heat pump unit (referred to as conventional steam double-effect unit or unit) Figure 1 As shown, it is composed of a low-pressure generator 1, a high-pressure generator 2, a condenser 3, a high-temperature heat exchanger 4, a low-temperature heat exchanger 5, an absorber 6, an evaporator 7, a solution pump 8, a refrigerant pump 9 and a control system (not shown in the figure) and pipes and valves connecting various components. Low-temperature water flows through the evaporator 7 to cool down; medium-temperature water flows through the absorber 6 and the condenser 3 to heat up; driving steam flows through the high-pressure generator 2, releasing heat to heat the concentrated lithium bromide solution, and condenses itself into saturated water and then flows out. When the unit is running, the refrigerant water drawn out by the refrigerant pump 9 and sprayed from the top of the evaporator 7 absorbs the heat of the low-temperature water flowing through the heat transfer tube of the evaporator 7, vaporizes into refrigerant steam, enters the absorber 6 and is absorbed by the lithium bromide concentrated solution, and the released heat is absorbed and taken away by the medium-temperature water flowing through the heat transfer tube of the absorber 6. After the lithium bromide concentrated solution absorbs the refrigerant vapor, its concentration becomes dilute. After being pumped out by the solution pump 8, it enters the high-pressure generator 2 through the low-temperature heat exchanger 5 and the high-temperature heat exchanger 4, and is heated and concentrated by the driving steam. The concentrated high-temperature refrigerant vapor enters the low-pressure generator 1, and the concentrated lithium bromide solution also enters the low-pressure generator 1 through the high-temperature heat exchanger 4, and is heated and concentrated again by the high-temperature refrigerant vapor from the high-pressure generator 2. The concentrated lithium bromide solution finally returns to the absorber 6 through the low-temperature heat exchanger 5. The high-temperature refrigerant vapor generated by the concentration of the solution in the high-pressure generator 2 is used as a heat source to heat and concentrate the lithium bromide solution in the low-pressure generator 1, and then it is cooled and condensed into refrigerant water. It and the refrigerant vapor concentrated from the solution in the low-pressure generator 1 both enter the condenser 3, are cooled and condensed by the medium-temperature water, and return to the evaporator 7.

[0003] After the saturated condensate of the driving steam of the conventional steam double-effect unit flows out from the high-pressure generator, it can be Figure 1 As shown in the figure, for the direct high-temperature and high-pressure outflow unit, for the steam condensate that needs to be lowered in temperature before discharge or recovery, the conventional steam double-effect unit basically exchanges heat with the condensate heat exchanger using a low-temperature dilute lithium bromide solution, which may be as follows Figure 2 The lithium bromide solution exiting the low temperature heat exchanger as shown enters the condensate heat exchanger for heat exchange, or as Figure 3 The lithium bromide dilute solution exiting the absorber at a lower temperature is fed into the condensate heat exchanger for heat exchange. Figure 2 In the process shown, since the dilute lithium bromide solution entering the condensate heat exchanger has been heated up in the low-temperature heat exchanger, its own temperature is relatively high, and it is impossible to reduce the steam condensate temperature to a very low level. Figure 3 In the process shown, although the temperature of the lithium bromide solution entering the condensate heat exchanger is low, the temperature of the steam condensate can be reduced to a very low level. However, due to the limitation of the solution circulation volume, that is, the total flow rate of the lithium bromide solution leaving the absorber, if the temperature of the steam condensate is reduced to a very low level to recover as much heat of the steam condensate as possible, it is necessary to increase the flow rate of the lithium bromide solution entering the condensate heat exchanger, thereby inevitably reducing the flow rate of the lithium bromide solution entering the low-temperature heat exchanger, thereby limiting the capacity of the lithium bromide solution to recover the heat of the lithium bromide concentrated solution in the low-temperature heat exchanger, resulting in the lithium bromide concentrated solution entering the absorber at a relatively high temperature and then being cooled by the medium-temperature water flowing through the absorber. The heat is taken out by the medium-temperature water and released to the external environment, thereby causing heat waste. If you want to reduce the temperature of the driving steam condensate as much as possible to recover more of its heat, and not increase the temperature of the lithium bromide concentrated solution leaving the low-temperature heat exchanger, you must reduce the temperature of the driving steam condensate entering the condensate heat exchanger as much as possible. Utility Model Content

[0004] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide a steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation, which can reduce the temperature of the driving steam condensate out of the unit without affecting the heat exchange effect of the low-temperature heat exchanger, that is, without increasing the outlet temperature of the concentrated solution of the low-temperature heat exchanger, thereby recovering and utilizing as much heat in the driving steam as possible.

[0005] The purpose of the utility model is achieved in this way:

[0006] A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation comprises a low-pressure generator, a high-pressure generator, a condenser, a high-temperature heat exchanger, a low-temperature heat exchanger, an absorber, an evaporator, a solution pump, and a refrigerant pump. It also comprises a condensate flash tank, driving steam to flow through the high-pressure generator and the condensate flash tank in sequence, the flash steam driven by the steam condensate flash evaporation in the condensate flash tank enters the low-pressure generator to release heat and condense, the condensate directly flows out of the unit or returns to the condensate flash tank, the steam condensate in the condensate flash tank flows out of the unit by gravity, or the condensate flash tank is equipped with a condensate delivery pump, and the steam condensate in the condensate flash tank is delivered by the condensate delivery pump.

[0007] Preferably, the steam condensate in the condensate flash tank is directly sent out of the unit via a condensate delivery pump.

[0008] Preferably, the steam condensate in the condensate flash tank is pumped out by a condensate delivery pump and sent out of the unit after passing through a low-pressure generator.

[0009] Preferably, it is further provided with a condensate heat exchanger, and the steam condensate in the condensate flash tank is pumped out by a condensate delivery pump and flows out of the unit after passing through the condensate heat exchanger;

[0010] Or it can be pumped out through the condensate transfer pump and flow out of the unit after passing through the low-pressure generator and the condensate heat exchanger.

[0011] Preferably, the dilute lithium bromide solution exiting the absorber flows in series through a low-temperature heat exchanger and a high-temperature heat exchanger into a high-pressure generator, then flows through the high-temperature heat exchanger into a low-pressure generator, and finally returns to the absorber through a low-temperature heat exchanger;

[0012] Or it first enters the low-pressure generator through the low-temperature heat exchanger, then enters the high-pressure generator through the high-temperature heat exchanger, and finally returns to the absorber through the high-temperature heat exchanger and the low-temperature heat exchanger;

[0013] Or it can be divided into two paths, one path enters the high-pressure generator through the high-temperature heat exchanger, and then returns to the absorber through the high-temperature heat exchanger, and the other path enters the low-pressure generator through the low-temperature heat exchanger, and then returns to the absorber through the low-temperature heat exchanger.

[0014] Preferably, the dilute lithium bromide solution exiting the absorber is divided into two paths, one path enters the high-pressure generator through the high-temperature heat exchanger, and then returns to the absorber through the high-temperature heat exchanger, and the other path flows in parallel through the low-temperature heat exchanger and the condensate heat exchanger, then enters the low-pressure generator, and then returns to the absorber through the low-temperature heat exchanger;

[0015] Or it first flows through the low-temperature heat exchanger and the condensate heat exchanger in parallel, then enters the high-pressure generator through the high-temperature heat exchanger, then enters the low-pressure generator through the high-temperature heat exchanger, and then returns to the absorber through the low-temperature heat exchanger after leaving the low-pressure generator;

[0016] Alternatively, it first flows through the low-temperature heat exchanger and the condensate heat exchanger in parallel and then enters the low-pressure generator. After exiting the low-pressure generator, it passes through the high-temperature heat exchanger and then enters the high-pressure generator, and finally returns to the absorber through the high-temperature heat exchanger and the low-temperature heat exchanger.

[0017] Preferably, the medium-temperature water flows through the absorber and the condenser in parallel, but it can also flow through the absorber and the condenser in any order.

[0018] The beneficial effects of the utility model are:

[0019] The saturated condensate of the driving steam from the high-pressure generator enters the condensate flash tank for flash evaporation. The flashed steam enters the low-pressure generator and is used as a heat source to heat the lithium bromide solution and then condenses. The condensate returns to the condensate flash tank or flows out of the unit directly. The steam condensate in the condensate flash tank flows out of the unit by gravity or is sent out by adding a condensate delivery pump.

[0020] When the temperature of the driving steam condensate needs to be lowered even further, a condensate heat exchanger can be added. A small portion of the low-temperature lithium bromide solution exiting the absorber can be separated and flowed through the condensate heat exchanger. The condensate transfer pump extracts the condensate from the condensate flash tank and sends it out of the unit after cooling it in the condensate heat exchanger, or sends it out of the unit after passing through the low-pressure generator and the condensate heat exchanger.

[0021] Compared with conventional steam double-effect units, there is no need for a condensate heat exchanger. The temperature of the driving steam condensate out of the unit can be reduced by a condensate flash tank, which is low in cost. When the temperature of the driving steam condensate needs to be reduced to a minimum, a condensate heat exchanger can be set. Since the temperature of the steam condensate coming out of the condensate flash tank and entering the condensate heat exchanger is much lower than the temperature of the driving steam saturated condensate, the heat contained in it is greatly reduced, so only a small amount of lithium bromide dilute solution is needed to exchange heat and cool it down. Under the condition of not affecting or less affecting the temperature of the lithium bromide concentrated solution out of the low-temperature heat exchanger, the temperature of the steam condensate out of the condensate heat exchanger can be reduced even lower, thereby making full use of the heat of the driving steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the working principle diagram of a conventional steam double-effect lithium bromide absorption refrigeration heat pump unit (the driving steam saturated condensate from the high-pressure generator flows directly out of the unit).

[0023] Figure 2 This is the working principle diagram of a conventional steam double-effect lithium bromide absorption refrigeration heat pump unit (the driving steam saturated condensate from the high-pressure generator enters the condensate heat exchanger, and the condensate heat exchanger exchanges heat with the lithium bromide solution from the low-temperature heat exchanger).

[0024] Figure 3 This is the working principle diagram of a conventional steam double-effect lithium bromide absorption refrigeration heat pump unit (the saturated condensate of driving steam from the high-pressure generator enters the condensate heat exchanger, and the condensate heat exchanger exchanges heat with the dilute lithium bromide solution exiting the absorber).

[0025] Figure 4 The working principle diagram of the application example 1 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0026] Figure 5 This is a working principle diagram of application example 2 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0027] Figure 6 This is a working principle diagram of application example 3 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0028] Figure 7This is a working principle diagram of application example 4 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0029] Figure 8 This is a working principle diagram of Application Example 5 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0030] Fig. 9 This is a working principle diagram of Application Example 6 of the steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation of the utility model.

[0031] Among them: low-pressure generator 1, high-pressure generator 2, condenser 3, high-temperature heat exchanger 4, low-temperature heat exchanger 5, absorber 6, evaporator 7, solution pump 8, refrigerant pump 9, condensate heat exchanger 10, condensate flash tank 11, condensate transfer pump 12.

[0032] Low-temperature water enters A1 and exits A2; medium-temperature water enters B1 and exits B2; driving steam enters C1 and driving steam condensate exits C2. DETAILED DESCRIPTION Example 1

[0033] See also Figure 4The utility model relates to a steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation. The steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation (hereinafter referred to as the unit) involved in the utility model is composed of a low-pressure generator 1, a high-pressure generator 2, a condenser 3, a high-temperature heat exchanger 4, a low-temperature heat exchanger 5, an absorber 6, an evaporator 7, a solution pump 8, a refrigerant pump 9, a condensate flash tank 11 and a control system (not shown in the figure) and pipes and valves connecting various components. Low-temperature water flows through the evaporator 7, and medium-temperature water flows through the absorber 6 and the condenser 3 in parallel, driving steam to flow through the high-pressure generator 2 to release heat and condense, and then enter the condensate flash tank 11. The flashed steam enters the low-pressure generator 1 to heat the solution and returns to the condensate flash tank 11 after releasing heat and condensing, and the condensed water flows out of the condensate flash tank 11. When the unit is running, the refrigerant water pumped out by the refrigerant pump 9 and sprayed from the top of the evaporator 7 absorbs the heat of the low-temperature water flowing through the heat transfer tube of the evaporator 7, and after being vaporized into refrigerant steam, enters the absorber 6 and is absorbed by the lithium bromide concentrated solution. The released heat is taken away by the medium-temperature water flowing through the heat transfer tube of the absorber 6. After the lithium bromide concentrated solution absorbs the refrigerant vapor, its concentration becomes dilute, and it is pumped out by the solution pump 8 and sent to the high-pressure generator 2 through the low-temperature heat exchanger 5 and the high-temperature heat exchanger 4, where it is heated and concentrated by the driving steam. The concentrated lithium bromide solution then enters the low-pressure generator 1 through the high-temperature heat exchanger 4, and the concentrated high-temperature refrigerant vapor also enters the low-pressure generator 1, and is used as a heat source to heat the concentrated lithium bromide solution therein again. The re-concentrated solution returns to the absorber 6 through the low-temperature heat exchanger 5, and the high-temperature refrigerant vapor generated by the concentration of the solution in the high-pressure generator 2 is used as a heat source to heat the concentrated solution in the low-pressure generator 1, and then it is cooled and condensed. It and the refrigerant vapor generated by the concentration of the solution in the low-pressure generator 1 both enter the condenser 3, are cooled and condensed by the medium-temperature water, and then return to the evaporator 7.

[0034] The flash steam generated by the flash condensation of the driving steam in the flash condensation tank 11 enters the low-pressure generator 1 to release heat and condense, and then returns to the flash condensation tank 11; it can also directly flow out of the unit after releasing heat and condensing in the low-pressure generator 1.

[0035] The steam condensate in the condensate flash tank 11 flows out by gravity.

[0036] The medium-temperature water flows through the absorber 6 and the condenser 3 in parallel, and it can also flow through the absorber 6 and the condenser 3 in any order.

[0037] The dilute lithium bromide solution exiting the absorber 6 flows in series through the low-temperature heat exchanger 5 and the high-temperature heat exchanger 4 into the high-pressure generator 2, then enters the low-pressure generator 1 through the high-temperature heat exchanger 4, and finally returns to the absorber 6 through the low-temperature heat exchanger 5; it can also first enter the low-pressure generator 1 through the low-temperature heat exchanger 5, then enter the high-pressure generator 2 through the high-temperature heat exchanger 4, and finally return to the absorber 6 through the high-temperature heat exchanger 4 and the low-temperature heat exchanger 5; it can also be divided into two paths, one path enters the high-pressure generator 2 through the high-temperature heat exchanger 4, and then returns to the absorber 6 through the high-temperature heat exchanger 4, and the other path enters the low-pressure generator 1 through the low-temperature heat exchanger 5, and then returns to the absorber 6 through the low-temperature heat exchanger 5. Example 2

[0038] See also Figure 5 The difference between this embodiment and embodiment 1 is that the condensate flash tank 11 is provided with a condensate output pump 12, and the flash steam flashed out of the driving steam condensate in the condensate flash tank 11 enters the low-pressure generator 1 to release heat and condense, and then returns to the condensate flash tank 11, and the steam condensate in the condensate flash tank 11 is sent out of the unit through the condensate delivery pump 12. Example 3

[0039] See also Figure 6 The difference between this embodiment and embodiment 1 is that the condensate flash tank 11 is provided with a condensate output pump 12, and the flash steam flashed out of the driving steam condensate in the condensate flash tank 11 enters the low-pressure generator 1 for heat release and condensation and then returns to the condensate flash tank 11, and the steam condensate in the condensate flash tank 11 is then pumped out by the condensate delivery pump 12 and sent out of the unit through the low-pressure generator 1. Example 4

[0040] See also Figure 7 The difference between this embodiment and embodiment 1 is that: a condensate delivery pump 12 and a condensate heat exchanger 10 are further provided. The flash steam from the driving steam condensate flash tank 11 enters the low-pressure generator 1 for heat release and condensation and then returns to the condensate flash tank 11. The steam condensate in the condensate flash tank 11 is then pumped out by the condensate delivery pump 12 and sent out of the unit through the condensate heat exchanger 10.

[0041] The dilute lithium bromide solution exiting the absorber 6 may first flow through the low-temperature heat exchanger 5 and the condensate heat exchanger 10 in parallel, then enter the high-pressure generator 2 through the high-temperature heat exchanger 4, then enter the low-pressure generator 1 through the high-temperature heat exchanger 4, and return to the absorber 6 through the low-temperature heat exchanger 5 after exiting the low-pressure generator 1; or it may first flow through the low-temperature heat exchanger 5 and the condensate heat exchanger 10 in parallel, then enter the low-pressure generator 1, then enter the high-pressure generator 2 through the high-temperature heat exchanger 4 after exiting the low-pressure generator 1, and finally return to the absorber 6 through the high-temperature heat exchanger 4 and the low-temperature heat exchanger 5. Example 5

[0042] See also Figure 8 The difference between this embodiment and embodiment 4 is that the flash steam from the driving steam condensation in the condensation flash tank 11 enters the low-pressure generator 1 for heat release and condensation and then returns to the condensation flash tank 11. The steam condensate in the condensation flash tank 11 is then pumped out by the condensate delivery pump 12 and sent out of the unit through the low-pressure generator 1 and the condensate heat exchanger 10. Example 6

[0043] See also Fig. 9 The difference between this embodiment and embodiment 5 is that:

[0044] The dilute lithium bromide solution exiting the absorber 6 is divided into two paths. One path enters the high-pressure generator 2 through the high-temperature heat exchanger 4, and then returns to the absorber 6 through the high-temperature heat exchanger 4. The other path flows in parallel through the low-temperature heat exchanger 5 and the condensate heat exchanger 10 and then enters the low-pressure generator 1, and then returns to the absorber 6 through the low-temperature heat exchanger 5.

[0045] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation, comprising a low-pressure generator (1), a high-pressure generator (2), a condenser (3), a high-temperature heat exchanger (4), a low-temperature heat exchanger (5), an absorber (6), an evaporator (7), a solution pump (8), and a refrigerant pump (9), characterized in that: It also includes a condensate flash tank (11), which drives steam to flow through the high-pressure generator (2) and the condensate flash tank (11) in sequence. The flash steam driven by the steam condensate flash in the condensate flash tank (11) enters the low-pressure generator (1) to release heat and condense. The condensed water directly flows out of the unit or returns to the condensate flash tank (11). The steam condensate in the condensate flash tank (11) flows out of the unit by gravity. Alternatively, the condensate flash tank (11) is equipped with a condensate delivery pump (12), and the steam condensate in the condensate flash tank (11) is delivered by the condensate delivery pump (12).

2. A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 1, characterized in that: The steam condensate in the condensate flash tank (11) is directly delivered out of the unit via the condensate delivery pump (12).

3. A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 1, characterized in that: The steam condensate in the condensate flash tank (11) is pumped out by the condensate delivery pump (12) and then delivered out of the unit through the low-pressure generator (1).

4. The steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 1, characterized in that: It is also provided with a condensate heat exchanger (10). The steam condensate in the condensate flash tank (11) is pumped out by the condensate delivery pump (12) and flows out of the unit after passing through the condensate heat exchanger (10); Alternatively, the condensate is pumped out through the condensate delivery pump (12) and flows out of the unit after passing through the low-pressure generator (1) and the condensate heat exchanger (10).

5. A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 1, 2 or 3, characterized in that: The dilute lithium bromide solution exiting the absorber (6) flows in series through the low-temperature heat exchanger (5) and the high-temperature heat exchanger (4) to enter the high-pressure generator (2), then enters the low-pressure generator (1) through the high-temperature heat exchanger (4), and finally returns to the absorber (6) through the low-temperature heat exchanger (5); Alternatively, the gas first enters the low-pressure generator (1) through the low-temperature heat exchanger (5), then enters the high-pressure generator (2) through the high-temperature heat exchanger (4), and finally returns to the absorber (6) through the high-temperature heat exchanger (4) and the low-temperature heat exchanger (5); Alternatively, the heat may be divided into two paths, one path entering the high-pressure generator (2) through the high-temperature heat exchanger (4) and then returning to the absorber (6) through the high-temperature heat exchanger (4); and the other path entering the low-pressure generator (1) through the low-temperature heat exchanger (5) and then returning to the absorber (6) through the low-temperature heat exchanger (5).

6. A steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 4, characterized in that: The lithium bromide dilute solution exiting the absorber (6) is divided into two paths, one path passes through the high-temperature heat exchanger (4) to enter the high-pressure generator (2), and then passes through the high-temperature heat exchanger (4) to return to the absorber (6), and the other path flows in parallel through the low-temperature heat exchanger (5) and the condensate heat exchanger (10) to enter the low-pressure generator (1), and then passes through the low-temperature heat exchanger (5) to return to the absorber (6); Alternatively, the liquid first flows in parallel through the low-temperature heat exchanger (5) and the condensate heat exchanger (10), then enters the high-pressure generator (2) through the high-temperature heat exchanger (4), then enters the low-pressure generator (1) through the high-temperature heat exchanger (4), and then returns to the absorber (6) through the low-temperature heat exchanger (5) after exiting the low-pressure generator (1); Alternatively, the liquid first flows through the low-temperature heat exchanger (5) and the condensate heat exchanger (10) in parallel and then enters the low-pressure generator (1). After exiting the low-pressure generator (1), the liquid then passes through the high-temperature heat exchanger (4) and then enters the high-pressure generator (2). Finally, the liquid returns to the absorber (6) through the high-temperature heat exchanger (4) and the low-temperature heat exchanger (5).

7. The steam double-effect lithium bromide absorption refrigeration heat pump unit with condensate flash evaporation according to claim 1, characterized in that: The medium-temperature water flows through the absorber (6) and the condenser (3) in parallel, and may also flow through the absorber (6) and the condenser (3) in any order.

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