Self-adjustable lithium bromide unit with prediction function

Abstract

The utility model belongs to the technical field of heat exchange equipment, and relates to a self-adjustable lithium bromide unit with a prediction function. The unit is composed of an absorber, an evaporator, a condenser, a low-temperature regenerator, a high-temperature regenerator, a low-temperature heat exchanger, a high-temperature heat exchanger, a refrigerant condensate heat recovery device, a low-temperature heat regenerator, a drainage device, a high-temperature heat regenerator, a dilute solution pump, a concentrated solution pump, a refrigerant pump, a temperature sensor, a flow regulating valve, a pressure sensor and a liquid level electrode. And the control center is provided with a prediction module. According to the utility model, the state of the unit is predicted through the prediction module, and the control center adjusts the unit according to the prediction result. And the running state of the unit adopting predictive control is more stable. When external conditions change drastically, the prediction control system responds more correctly and quickly. And safe and stable operation of the unit is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat exchange equipment and relates to a self-regulating lithium bromide unit with a prediction function. Background Art

[0002] Lithium bromide refrigeration units use water as refrigerant and lithium bromide solution as absorbent. With the advantages of high energy efficiency and green environmental protection, lithium bromide refrigeration units are widely used in the industrial field. The complex and changeable conditions in the industrial system have a huge impact on the control system of the lithium bromide unit. At present, the control system of the lithium bromide unit mainly detects and controls cold water, cooling water and heat source, and the control means are relatively simple. When the cold water, cooling water and heat source change too fast or the change is more complex, the unit cannot make corresponding changes in time and accurately, affecting the operation of the unit. Therefore, how to design a more intelligent and self-adjustable unit that meets the actual operating conditions of the unit has become an urgent issue to be solved. Utility Model Content

[0003] In order to solve the above problems, the utility model provides a self-adjustable lithium bromide unit with a prediction function.

[0004] The technical solution adopted by the utility model to achieve the above-mentioned purpose is: a self-regulating lithium bromide unit with a prediction function, characterized in that it includes an evaporator, an absorber, a condenser, a low-temperature regenerator, a high-temperature regenerator, a refrigerant condensate heat recovery device, a low-temperature heat exchanger, a heat recovery device, a high-temperature heat exchanger, a refrigerant pump, a dilute solution pump, a concentrated solution pump and a control center with a prediction module; wherein the absorber and the evaporator are arranged in a cylinder, the condenser and the low-temperature regenerator are arranged in a cylinder, and a dilute solution pump is arranged below the cylinder where the evaporator and the absorber are arranged;

[0005] A dilute liquid pipeline B and a dilute liquid pipeline C are arranged in parallel on the dilute liquid pipeline A connected to the outlet of the dilute solution pump, a refrigerant condensate heat recovery device is arranged on the dilute liquid pipeline B, a low-temperature heat exchanger is arranged on the dilute liquid pipeline C, the ends of the converging pipelines of the dilute liquid pipelines B and C are connected to the dilute liquid pipeline D, the end of the dilute liquid pipeline D is connected to the high-temperature regenerator, the high-temperature regenerator is connected to the high-temperature heat exchanger through the intermediate liquid pipeline A, the high-temperature heat exchanger is connected to the low-temperature regenerator through the intermediate liquid pipeline B, the low-temperature regenerator is connected to the low-temperature heat exchanger through the concentrated liquid pipeline A, a concentrated solution pump is arranged on the concentrated liquid pipeline A, the low-temperature heat exchanger is connected to the absorber through the concentrated liquid pipeline B, the high-temperature regenerator and the low-temperature regenerator are connected through a refrigerant steam pipeline, the low-temperature regenerator is connected to the refrigerant condensate heat recovery device through the refrigerant steam condensate pipeline A, the refrigerant condensate heat recovery device is connected to the condenser through the refrigerant steam condensate pipeline B, and a refrigerant pump is also arranged below the absorber and the evaporator cylinder.

[0006] The high-temperature regenerator is connected to a steam inlet pipeline, a steam control valve is arranged on the steam inlet pipeline, the high-temperature regenerator is connected to a heat recovery device through a steam condensate pipeline, a drain device is arranged on the steam condensate pipeline, and the heat recovery device is connected to a steam condensate outlet pipeline.

[0007] The condenser and the evaporator are connected via a refrigerant water pipeline B, a refrigerant pump is arranged on the refrigerant water pipeline C, and the refrigerant water pipeline C is connected to the absorber via the refrigerant water pipeline A.

[0008] The refrigerant water pipeline C is provided with a refrigerant temperature sensor A, and the refrigerant water pipeline B is provided with a refrigerant temperature sensor B.

[0009] The evaporator is connected to the cold water inlet pipeline and the cold water outlet pipeline respectively. A cold water inlet temperature sensor and a cold water inlet regulating valve are arranged on the cold water inlet pipeline. A cold water outlet temperature sensor and a cooling water inlet regulating valve are arranged on the cold water outlet pipeline. The condenser is connected to the cooling water inlet pipeline. A cooling water inlet temperature sensor is arranged on the cooling water inlet pipeline. The absorber is connected to the cooling water outlet pipeline. A cooling water outlet temperature sensor is arranged on the cooling water outlet pipeline. The condenser and the absorber are connected through a cooling water pipeline.

[0010] The dilute liquid pipeline A is provided with a dilute liquid temperature sensor and a dilute liquid flow regulating valve A, the dilute liquid pipeline B is provided with a dilute liquid flow regulating valve C, and the dilute liquid pipeline C is provided with a dilute liquid flow regulating valve B.

[0011] The concentrate pipeline A is provided with a concentrate temperature sensor and a concentrate flow regulating valve in sequence, the intermediate liquid pipeline B is provided with an intermediate liquid flow regulating valve, and the refrigerant steam condensate pipeline B is provided with a refrigerant steam condensate regulating valve.

[0012] The dilute solution pump is provided with a frequency converter, and the high temperature regenerator is provided with a high re-liquid level gauge. The frequency conversion and start-stop control of the dilute solution pump are performed based on the comparison between the pressure detected by the high re-pressure sensor and the set pressure of the high temperature regenerator and the liquid level fed back by the liquid level detection device.

[0013] The control center of the unit with a prediction module includes all sensors connected to various parts, a control center, and a prediction module. The sensors are connected to the control center signal, and the control center is connected to the prediction module. The prediction module records the unit operation data, predicts the upcoming data changes and the adverse consequences that may occur based on the changing trend of the unit's operating status, and determines in a short time whether the predicted data and the actual measured data change trends are consistent. After feedback, the control center adjusts the regulation process based on past experience data to ensure the stability of the unit's operating status. The unit is applicable to steam-type units, direct-fired units, and flue gas absorption units.

[0014] The beneficial effect of the utility model is as follows: by adding a prediction module to the control center, after the control center receives the cooling water inlet temperature, cold water inlet temperature, cold water outlet temperature, high temperature regenerator pressure, refrigerant condensate temperature, high temperature regenerator liquid level, dilute liquid concentration, and concentrated liquid concentration, the prediction module comprehensively judges and predicts the changes that will occur in the unit. According to the prediction results, the opening of the cold water regulating valve, the opening of the cooling water regulating valve, the opening of the steam control valve, the refrigerant steam condensate flow regulating valve, the solution pump frequency, and the refrigerant pump frequency are adjusted. The cold water flow, cooling water flow, solution circulation volume, refrigerant circulation volume, and heat source input volume can be adjusted in advance. The refrigerant pollution, the reduction of the unit's refrigeration capacity, and the unit alarm caused by changes in external conditions and changes in the unit itself can be effectively avoided, and the unit can be operated smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The utility model is a schematic diagram of the structure of a self-adjustable lithium bromide refrigeration unit with a prediction function.

[0016] Figure 2 The utility model is a control flow chart of a self-regulating lithium bromide unit with a prediction function.

[0017] Figure 3 This is a curve chart showing the fluctuation of the cold water outlet temperature of the lithium bromide unit without adding the prediction module.

[0018] Figure 4 This is a curve chart showing fluctuations in the cold water outlet temperature of a lithium bromide unit with a prediction module added.

[0019] In the figure: 1-evaporator, 2-absorber, 3-condenser, 4-low temperature regenerator, 5-high temperature regenerator, 6-refrigerant condensate heat recovery device, 7-low temperature heat exchanger, 8-heat recovery device, 9-high temperature heat exchanger, 10-refrigerant pump, 11-dilute solution pump, 12-concentrated solution pump, 13-dilute solution pipeline A, 14-dilute solution pipeline B, 15-dilute solution pipeline C, 16-dilute solution pipeline D, 17-intermediate liquid pipeline Line A, 18-intermediate liquid pipeline B, 19-concentrated liquid pipeline A, 20-concentrated liquid pipeline B, 21-refrigerant steam pipeline, 22-refrigerant steam condensate pipeline A, 23-refrigerant steam condensate pipeline B, 24-steam inlet pipeline, 25-steam condensate pipeline, 26-steam condensate outlet pipeline, 27-drain device, 28-refrigerant water pipeline A, 29-refrigerant water pipeline B, 30-refrigerant water pipeline C, 31 -cold water inlet pipeline, 32-cold water outlet pipeline, 33-cooling water inlet pipeline, 34-cooling water outlet pipeline, 35-cooling water pipeline, 36-cold water inlet temperature sensor, 37-cold water outlet temperature sensor, 38-cooling water inlet temperature sensor, 39-cooling water outlet temperature sensor, 40-steam control valve, 41-dilute liquid temperature sensor, 42-concentrated liquid temperature sensor, 43-refrigerant temperature sensor A, 44-refrigerant temperature sensor B, 45-cold water inlet regulating valve, 46-cooling water inlet regulating valve, 47-dilute liquid flow regulating valve A, 48-dilute liquid flow regulating valve B, 49-dilute liquid flow regulating valve C, 50-refrigerant steam condensate regulating valve, 51-intermediate liquid regulating valve, 52-high re-pressure sensor, 53-high re-level gauge, 54-frequency converter, 55-concentrated liquid flow regulating valve. DETAILED DESCRIPTION

[0020] The utility model is further described below in conjunction with the accompanying drawings and specific embodiments: Example

[0021] like Figure 1A self-regulating lithium bromide unit with a prediction function is shown. It consists of an absorber 2, an evaporator 2, a condenser 3, a low-temperature regenerator 4, a high-temperature regenerator 5, a low-temperature heat exchanger 7, a high-temperature heat exchanger 9, a refrigerant condensate heat recovery device 6, a low-temperature heat exchanger 7, a high-temperature heat exchanger 9, a heat recovery device 8, a dilute solution pump 11, a concentrated solution pump 12, a refrigerant pump 10 and a control center with a prediction module. The absorber 2 and the evaporator 1 are arranged in a cylinder, the condenser 3 and the low-temperature regenerator 4 are arranged in a cylinder, a dilute solution pump 11 is arranged at the lower part of the cylinder where the evaporator 1, the absorber 2 and the evaporator are arranged, a dilute solution pipeline B14 and a dilute solution pipeline C15 are arranged in parallel on the dilute solution pipeline A13 connected to the outlet of the dilute solution pump 11, a refrigerant condensate heat recovery device 6 is arranged on the dilute solution pipeline B14, a low-temperature heat exchanger 7 is arranged on the dilute solution pipeline C15, the end of the converging pipeline of the dilute solution pipeline B14 and the dilute solution pipeline C15 is connected to the dilute solution pipeline D16, the end of the dilute solution pipeline D is connected to the high-temperature regenerator 5, and the high-temperature regenerator 5 is connected to the intermediate concentration solution. The liquid pipeline A18 is connected to the high-temperature heat exchanger 9, the high-temperature heat exchanger is connected to the low-temperature regenerator 4 through the intermediate concentration solution pipeline B18, the low-temperature regenerator is connected to the low-temperature heat exchanger 7 through the concentrated solution pipeline A19, a concentrated solution pump 12 is provided on the concentrated solution pipeline A, the low-temperature heat exchanger 7 is connected to the absorber 2 through the concentrated solution pipeline B20, the high-temperature regenerator 5 and the low-temperature regenerator 4 are connected through the refrigerant steam pipeline 21, the low-temperature regenerator 4 is connected to the refrigerant condensate heat recovery device 6 through the refrigerant steam condensate pipeline A25, the refrigerant condensate heat recovery device 6 is connected to the condenser 3 through the refrigerant steam condensate pipeline B23, and a refrigerant pump 10 is also provided below the absorber and evaporator cylinders. The absorber 2, the low-temperature regenerator 4, the high-temperature regenerator 5, the low-temperature heat exchanger 7, the high-temperature heat exchanger 9, the refrigerant condensate heat recovery device 6, the heat recovery device 811, the dilute solution pump 11, and the concentrated solution pump 12 form a solution cycle, that is, the dilute solution from the absorber 2 is sent to the dilute solution pipeline A3 by the dilute solution pump 11 and then divided into two paths, one path passes through the dilute solution pipeline B14 and passes through the refrigerant condensate heat recovery device 6, and the other path enters the dilute solution pipeline C5 and passes through the low-temperature heat exchanger 7. After the dilute solutions converge, they enter the high-temperature regenerator 5 through the dilute solution pipeline D42 to be heated and concentrated to form an intermediate concentration solution. The intermediate concentration solution It enters the high-temperature heat exchanger 9 through the intermediate concentration solution pipeline A17 for cooling, and then enters the low-temperature regenerator 4 through the intermediate concentration solution pipeline B18, and is heated and concentrated by the refrigerant steam from the high-temperature regenerator 5 through the refrigerant steam pipeline 21 into the low-temperature regenerator 4 to form a concentrated solution. The concentrated solution passes through the concentrated solution pump 12 and passes through the low-temperature heat exchanger 7 for heat exchange, and the temperature of the concentrated solution is reduced. It returns to the absorber 2 through the concentrated solution pipeline B20 and drips on the cooling water pipe, absorbs the refrigerant steam from the evaporator 1, and becomes a dilute solution. At the same time, the refrigerant water drips on the cold water pipe of the evaporator 1 to cool the cold water entering the evaporator 1, thereby realizing refrigeration.

[0022] The high-temperature regenerator 5 is connected to the steam inlet pipeline 24, and a steam control valve 40 is arranged on the steam inlet pipeline 24. The high-temperature regenerator 5 is connected to the heat recovery device 8 through a steam condensate pipeline 25, and a drain device 27 is arranged on the steam condensate pipeline 25. The heat recovery device 8 is connected to the steam condensate outlet pipeline 26.

[0023] The condenser 3 and the evaporator 1 are connected via a refrigerant water pipeline B29, a refrigerant pump is arranged on the refrigerant water pipeline C30, and the refrigerant water pipeline C30 is connected to the absorber 2 via a refrigerant water pipeline A28.

[0024] The evaporator 1 is connected to a cold water inlet pipeline 31 and a cold water outlet pipeline 32 respectively, a cold water inlet temperature sensor 36 is arranged on the cold water inlet pipeline, and a cold water outlet temperature sensor 37 is arranged on the cold water outlet pipeline 32; the condenser 3 is connected to a cooling water inlet pipeline 33, and a cooling water inlet temperature sensor 38 is arranged on the cooling water inlet pipeline 33; the absorber 2 is connected to a cooling water outlet pipeline 34, and a cooling water outlet temperature sensor 39 is arranged on the cooling water outlet pipeline 34; the condenser 3 and the absorber 2 are connected via a cooling water pipeline 35.

[0025] The dilute liquid pipeline A3 is provided with a dilute liquid temperature sensor 41 and a dilute liquid flow regulating valve A47 in sequence. The dilute liquid pipeline B14 is provided with a dilute liquid flow regulating valve C49, and the dilute liquid pipeline C15 is provided with a dilute liquid flow regulating valve B48.

[0026] The concentrate pipeline A19 is provided with a concentrate temperature sensor 42 and a concentrate flow regulating valve 55 in sequence. The intermediate liquid pipeline A17 is provided with an intermediate liquid flow regulating valve 51 .

[0027] A refrigerant steam condensate regulating valve 50 is provided on the refrigerant steam condensate pipeline B23.

[0028] The dilute solution pump 11 is provided with a frequency converter 54, and the high temperature regenerator 5 is provided with a high re-liquid level gauge 53. The frequency conversion and start-stop control of the dilute solution pump are performed based on the comparison between the detection pressure of the high re-pressure sensor 52 and the set pressure of the high temperature regenerator 5 and the liquid level fed back by the liquid level detection device.

[0029] The control center with a prediction module of the unit includes all sensors connected to various parts, a control center, and a prediction module. The sensors are connected to the control center signal, and the control center is connected to the prediction module. The prediction module records the unit operation data, predicts the upcoming data changes and the adverse consequences according to the changing trend of the unit operation status, and judges whether the predicted data and the actual measured data change trends are consistent in a short time. After feedback, the control center adjusts the regulation process according to the previous experience data to ensure the stability of the unit operation status; the unit with a prediction function is not limited to steam-type units, but can also be direct-fired, flue gas and other absorption units.

[0030] like Figure 2 The figure shows a brief adjustment process of the control center with a prediction module. The unit detects the operating status of the unit through sensors in various parts. When the balance of the unit changes, the prediction module predicts the upcoming data changes and the adverse results according to the change trend, and judges whether the predicted data and the actual measured data change trend are consistent in a short time. If the judgment is correct, the control center can respond in time, and return the unit to a healthy balance state by changing the degree of opening and closing of the flow regulating solenoid valve, adjusting the pump frequency and other adjustment means. For example, when the cold water temperature and cooling water temperature are detected to deviate from the set value, adjust the cold water and cooling water inlet regulating valves to return the cold water cooling water flow temperature to the normal range, and adjust the opening of the steam control valve according to the cold water cooling water outlet temperature to control the heat source input to prevent the evaporator from freezing the pipe. By detecting the cooling water inlet temperature, high-temperature regenerator pressure, and refrigerant condensate temperature, the opening of the refrigerant condensate regulating valve is controlled in real time to prevent the accumulation of refrigerant steam condensate in the heat transfer tube of the low-temperature regenerator and cause the unit performance to decline. By detecting the high-temperature regenerator pressure and liquid level, controlling the frequency conversion and start and stop of the dilute solution pump, the liquid level stability in the high-temperature regenerator is improved, and the heat source input of the high-temperature regenerator is changed to ensure the stability of the high-temperature regenerator. At the same time, the preparatory module can record the unit operation data and adjust the adjustment process based on past experience data to ensure the stability of the unit operation status.

[0031] like Figure 3-Figure 4 By adding a prediction module, the adjustment speed and accuracy of the unit are significantly increased.

[0032] The above-mentioned embodiments are only preferred embodiments of the present invention, but not all feasible embodiments of the present invention. For those skilled in the art, any obvious changes made to the present invention without departing from the principle and spirit of the present invention should be considered to be included in the scope of protection of the claims of the present invention.

Claims

1. A self-regulating lithium bromide unit with a predictive function, characterized in that: The invention comprises an evaporator (1), an absorber (2), a condenser (3), a low-temperature regenerator (4), a high-temperature regenerator (5), a refrigerant condensate heat recovery device (6), a low-temperature heat exchanger (7), a heat recovery device (8), a high-temperature heat exchanger (9), a refrigerant pump (10), a dilute solution pump (11), a concentrated solution pump (12) and a control center with a prediction module; wherein the absorber (2) and the evaporator (1) are arranged in a cylinder, the condenser (3) and the low-temperature regenerator (4) are arranged in a cylinder, and the dilute solution pump (11) is arranged below the cylinder in which the evaporator (1) and the absorber (2) are arranged; A dilute solution pipeline B (14) and a dilute solution pipeline C (15) are arranged in parallel on the dilute solution pipeline A (13) connected to the outlet of the dilute solution pump (11); a refrigerant condensate heat recovery device (6) is arranged on the dilute solution pipeline B (14); a low-temperature heat exchanger (7) is arranged on the dilute solution pipeline C (15); the ends of the converging pipelines of the dilute solution pipelines B (14) and C (15) are connected to the dilute solution pipeline D (16); the end of the dilute solution pipeline D (16) is connected to the high-temperature regenerator (5); the high-temperature regenerator (5) is connected to the high-temperature heat exchanger (9) via the intermediate solution pipeline A (17); the high-temperature heat exchanger (9) is connected to the low-temperature regenerator (4) via the intermediate solution pipeline B (18); The low-temperature regenerator (4) is connected to the low-temperature heat exchanger (7) via a concentrated solution pipeline A (19), and a concentrated solution pump (12) is arranged on the concentrated solution pipeline A (19). The low-temperature heat exchanger (7) is connected to the absorber (2) via a concentrated solution pipeline B (20). The high-temperature regenerator (5) and the low-temperature regenerator (4) are connected via a refrigerant steam pipeline (21). The low-temperature regenerator (4) is connected to the refrigerant condensate heat recovery device (6) via a refrigerant steam condensate pipeline A (22). The refrigerant condensate heat recovery device (6) is connected to the condenser (3) via a refrigerant steam condensate pipeline B (23). A refrigerant pump (10) is also arranged below the absorber (2) and the evaporator (1) cylinder.

2. A self-regulating lithium bromide unit with a predictive function according to claim 1, characterized in that: The high-temperature regenerator (5) is connected to a steam inlet pipeline (24), a steam control valve (40) is provided on the steam inlet pipeline (24), the high-temperature regenerator (5) and the heat recovery device (8) are connected via a steam condensate pipeline (25), a drain device (27) is provided on the steam condensate pipeline (25), and the heat recovery device (8) is connected to a steam condensate outlet pipeline (26).

3. A self-regulating lithium bromide unit with a predictive function according to claim 2, characterized in that: The condenser (3) and the evaporator (1) are connected via a refrigerant water pipeline B (29), a refrigerant pump (10) is provided on the refrigerant water pipeline C (30), and the refrigerant water pipeline C (30) is connected to the absorber (2) via a refrigerant water pipeline A (28).

4. A self-regulating lithium bromide unit with a predictive function according to claim 3, characterized in that: A refrigerant temperature sensor A (43) is provided on the refrigerant water pipeline C (30), and a refrigerant temperature sensor B (44) is provided on the refrigerant water pipeline B (29).

5. The self-regulating lithium bromide unit with prediction function according to claim 1 is characterized in that: The evaporator (1) is connected to a cold water inlet pipeline (31) and a cold water outlet pipeline (32) respectively; a cold water inlet temperature sensor (36) and a cold water inlet regulating valve (45) are arranged on the cold water inlet pipeline (31); a cold water outlet temperature sensor (37) and a cooling water inlet regulating valve (46) are arranged on the cold water outlet pipeline (32); the condenser (3) is connected to the cooling water inlet pipeline (33); a cooling water inlet temperature sensor (38) is arranged on the cooling water inlet pipeline (33); the absorber (2) is connected to the cooling water outlet pipeline (34); a cooling water outlet temperature sensor (39) is arranged on the cooling water outlet pipeline (34); and the condenser (3) and the absorber (2) are connected via a cooling water pipeline (35).

6. A self-regulating lithium bromide unit with a predictive function according to claim 1, characterized in that: The dilute liquid pipeline A (13) is provided with a dilute liquid temperature sensor (41) and a dilute liquid flow regulating valve A (47), the dilute liquid pipeline B (14) is provided with a dilute liquid flow regulating valve C (49), and the dilute liquid pipeline C (15) is provided with a dilute liquid flow regulating valve B (48).

7. The self-regulating lithium bromide unit with prediction function according to claim 1 is characterized in that: A concentrate temperature sensor (42) and a concentrate flow regulating valve (55) are sequentially arranged on the concentrate pipeline A (19), an intermediate liquid flow regulating valve (51) is arranged on the intermediate liquid pipeline B (18), and a refrigerant steam condensate regulating valve (50) is arranged on the refrigerant steam condensate pipeline B (23).

8. The self-regulating lithium bromide unit with prediction function according to claim 1 is characterized in that: The dilute solution pump (11) is provided with a frequency converter (54), and the high temperature regenerator (5) is provided with a high regenerator level gauge (53). The frequency conversion and start / stop control of the dilute solution pump are performed based on the comparison between the detection pressure of the high regenerator pressure sensor (52) and the set pressure of the high temperature regenerator (5) and the liquid level fed back by the liquid level detection device.

9. A self-regulating lithium bromide unit with a prediction function according to any one of claims 1 to 8, characterized in that: The control center of the unit with a prediction module includes all sensors connected to various parts, a control center, and a prediction module. The sensors are connected to the control center signal, and the control center is connected to the prediction module. The prediction module records the unit operation data, predicts the upcoming data changes and the adverse consequences that may occur based on the changing trend of the unit's operating status, and determines in a short time whether the predicted data and the actual measured data change trends are consistent. After feedback, the control center adjusts the regulation process based on past experience data to ensure the stability of the unit's operating status. The unit is applicable to steam-type units, direct-fired units, and flue gas absorption units.

Images