Low-dew-point dehumidification unit of paper pulp transport ship

Abstract

The utility model relates to a low-dew-point dehumidification unit of a paper pulp transport ship, which relates to the field of refrigeration air conditioners and comprises a fresh air subsystem and an air return subsystem which both pass through the same dehumidification rotating wheel. The fresh air subsystem comprises a condenser, a regeneration filter screen, a regeneration heater, a dehumidification rotating wheel and a regeneration fan which are sequentially arranged along a fresh air transmission path, and the return air subsystem comprises a primary filter screen, an evaporator, a dehumidification rotating wheel and an air feeder which are sequentially arranged along a return air transmission path. Air flowing back from the cargo hold is cooled through the refrigeration dehumidification surface air cooler, part of moisture is removed, and then the air enters the macromolecule rotating wheel to be further dried, so that the lower dew point temperature is achieved. The dehumidification system can dehumidify air in the cargo hold, ensures that the temperature of the cargo hold does not rise again, and avoids the risk of condensation of the cargo hold cover caused by a large amount of water vapor generated when the dehumidification system adsorbs heat to accelerate re-evaporation of the cargo.

Description

Technical Field

[0001] The utility model relates to the field of refrigeration and air conditioning, and relates to a low dew point ship cargo hold dehumidification technology. Background Art

[0002] Pulp ships are used to transport pulp, and the loading ports are generally in Uruguay and Brazil in South America and Finland in the Baltic Sea. Unloading is generally done at ports in Europe, the Mediterranean and the Far East. In order to keep the cargo dry during transportation, a dedicated cargo hold dehumidification and drying system is required. For global routes across oceans, the navigation areas are complex and changeable, which causes certain difficulties in cargo loading and unloading and management. In the past, traditional adsorption drying and dehumidification units were reported by shipowners to have condensation in the cargo hold during transportation, which would cause damage to some cargo. As the air temperature and seawater temperature dropped rapidly, the hull temperature dropped accordingly, but the pulp temperature in the hold was relatively high. As a clean cargo that is easy to generate water vapor, pulp will generate a lot of water vapor during transportation. In the traditional single-rotor dehumidifier, the dehumidifier rotor is filled with hygroscopic materials such as molecular sieves. During the moisture absorption process, due to the thermophysical properties of the adsorbent, a large amount of adsorption heat will be generated, resulting in an increase in the dehumidifier outlet temperature. Part of this adsorbed heat cargo hold is transferred to the outside through the hatch cover, and part of it causes the temperature in the cabin to rise. The high temperature cargo hold intensifies the evaporation of water in the pulp and increases the load of the dehumidifier. If the original design system is not well considered, the dehumidifier's ability to take away this part of the water vapor will cause the dew point temperature of the cabin to rise, which is higher than the temperature of the bulkhead, and the bulkhead will condense. The dehumidifier cannot reduce the humidity in the cabin in a short time. In addition, the temperature of the hull is reduced, which makes it easier to generate a large amount of condensed water on the back of the hatch cover. If it is not discovered in time and correct measures are not taken, it is very easy to cause cargo damage and bulging. In response to this problem, a new type of special dehumidification system is urgently needed to achieve the purpose of safe and convenient transportation of goods. Utility Model Content

[0003] The utility model aims to provide a low dew point dehumidifier unit for pulp transport ships, so as to avoid the risk of condensation on hatch covers caused by heat adsorption by the dehumidification system accelerating the re-evaporation of cargo and generating a large amount of water vapor.

[0004] In order to achieve the above-mentioned purpose, the technical solution of the utility model provides a low dew point dehumidification unit for a pulp transport ship, including a fresh air subsystem and a return air subsystem, both of which pass through the same dehumidification wheel, the fresh air subsystem includes a condenser, a regeneration filter, a regeneration heater, the dehumidification wheel, and a regeneration fan arranged in sequence along the fresh air transmission path, and the return air subsystem includes a primary filter, an evaporator, the dehumidification wheel, and a blower arranged in sequence along the return air transmission path.

[0005] Preferably, the pipeline between the condenser and the regeneration filter is further connected with a pipeline leading to a condensing fan.

[0006] Preferably, the dehumidifier casing is composed of an upper and lower structural casing, the condenser, the blower, the evaporator, and the primary filter are located in the lower structural casing, the condensing fan, the regeneration filter, and the regeneration heater are located in the upper structural casing, the dehumidification wheel occupies the upper and lower structural casings, and the regeneration fan and compressor are located on the top of the lower structural casing.

[0007] Preferably, temperature sensors are provided at the inlet end of the primary filter, between the evaporator and the dehumidification wheel, between the dehumidification wheel and the blower, at the outlet end of the blower, at the inlet end of the condenser, between the regeneration filter and the dehumidification wheel, and between the dehumidification wheel and the regeneration fan; dew point temperature sensors are provided at the inlet end of the primary filter and the outlet end of the blower; pressure sensors are provided at the inlet and outlet ends of the compressor; an over-temperature switch is provided between the regeneration filter and the regeneration heater.

[0008] Preferably, the automatic control system is composed of a PLC controller, the pressure sensor, the temperature sensor, the humidity sensor and low-voltage electrical components.

[0009] Preferably, the evaporator and the condenser are further connected to an expansion valve and the compressor to form a refrigeration subsystem.

[0010] Preferably, a hot gas bypass valve is further connected to the pipeline between the evaporator and the expansion valve and the pipeline between the condenser and the compressor.

[0011] Preferably, the dehumidifier case includes a main frame and a panel. The main frame frames are connected by a three-prong connection. The panel is a sandwich structure composed of an upper metal plate and rock wool insulation material in the middle. The panel and the frame assembly are connected by screws and sealed with a rubber sealing strip.

[0012] Preferably, the condensing fan adopts a DC variable frequency fan, and the fan speed can be automatically adjusted according to the condensing pressure to achieve the set condensing temperature and the air outlet temperature of the condenser.

[0013] Preferably, the regeneration heater is controlled by a thyristor, with multi-stage energy regulation, and the regeneration temperature setting value tracks the change of ambient temperature.

[0014] In summary, the utility model includes the following beneficial technical effects:

[0015] The air returning from the cargo hold is first cooled by the refrigerated dehumidifier to remove some of the moisture, and then enters the polymer rotor for further drying to reach a lower dew point temperature. The utility model can not only dehumidify the cargo hold air, but also ensure that the temperature of the cargo hold does not rise again, avoiding the risk of the dehumidification system absorbing heat to accelerate the evaporation of the cargo again and generate a large amount of water vapor, causing condensation on the hatch cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the principle of a low dew point dehumidification unit for a pulp transport ship according to the utility model;

[0017] Figure 2 This is a schematic diagram of the main structure of a low dew point dehumidifier unit for a pulp transport ship according to the utility model;

[0018] Figure 3 This is a schematic diagram of the top view of the structure of a low dew point dehumidifier unit for a pulp transport ship according to the utility model;

[0019] Figure 4 The utility model is a side view structural schematic diagram of a low dew point dehumidification unit for a pulp transport ship.

[0020] Figure numerals: 1. primary filter; 2. evaporator; 3. regeneration fan; 4. dehumidification wheel; 5. regeneration heater; 6. regeneration filter; 7. air blower; 8. condenser; 9. condensing fan; 10. compressor. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] The utility model provides a low dew point combined dehumidification unit that integrates a low temperature regeneration polymer material dehumidification rotor 4 system and a refrigeration dehumidification system. The air returning from the cargo hold is first cooled by a refrigeration dehumidification surface cooler to remove part of the moisture, and then enters the polymer rotor for further drying to reach a lower dew point temperature. This system can not only dehumidify the cargo hold air, but also ensure that the cargo hold temperature does not rise, avoiding the risk of the dehumidification system adsorbing heat to accelerate the evaporation of the cargo again and generate a large amount of water vapor, resulting in condensation on the hatch cover.

[0023] The dehumidifier principle and internal components are attached. Figure 1 And attached Figure 2 The dehumidifier is composed of a refrigeration compressor 10, an air-cooled condenser 8, a dehumidification evaporator 2, an electronic expansion valve, a hot gas bypass valve, a polymer dehumidification rotor 4, a dry air blower 7, a regeneration blower 3, a condensing blower 9, a regeneration heater 5, a PLC control box, and a plurality of temperature sensors, humidity sensors, etc.

[0024] Specifically, the utility model includes a fresh air subsystem and a return air subsystem, both of which pass through the same dehumidification wheel 4, the fresh air subsystem includes a condenser 8, a regeneration filter 6, a regeneration heater 5, a dehumidification wheel 4, and a regeneration fan 3 arranged in sequence along the fresh air transmission path, the return air subsystem includes a primary filter 1, an evaporator 2, a dehumidification wheel 4, and a blower 7 arranged in sequence along the return air transmission path, the pipeline between the condenser 8 and the regeneration filter 6 is further connected with a pipeline leading to the condensing fan 9, the evaporator 2 and the condenser 8 are further connected with an expansion valve and a compressor 10 to form a refrigeration subsystem, and the pipeline between the evaporator 2 and the expansion valve and the pipeline between the condenser 8 and the compressor 10 are further connected with a hot air bypass valve.

[0025] Preferably, the dehumidifier casing of the utility model is composed of an upper and lower structural casing, the condenser 8, the blower 7, the evaporator 2, and the primary filter 1 are located in the lower structural casing, the condensing fan 9, the regeneration filter 6, and the regeneration heater 5 are located in the upper structural casing, the dehumidification wheel 4 occupies the upper and lower structural casings, and the regeneration fan 3 and the compressor 10 are located on the top of the lower structural casing.

[0026] Among them, temperature sensors are provided at the inlet end of the primary filter 1, between the evaporator 2 and the dehumidification wheel 4, between the dehumidification wheel 4 and the air blower 7, at the outlet end of the air blower 7, at the inlet end of the condenser 8, between the regeneration filter 6 and the dehumidification wheel 4, and between the dehumidification wheel 4 and the regeneration fan 3. Dew point temperature sensors are provided at the inlet end of the primary filter 1 and the outlet end of the air blower 7. Pressure sensors are provided at the inlet and outlet ends of the compressor 10. An over-temperature switch is provided between the regeneration filter 6 and the regeneration heater 5. The automatic control system is composed of a PLC controller, a pressure sensor, a temperature sensor, a humidity sensor and low-voltage electrical components.

[0027] Specifically, the structural design of the marine combined low dew point dehumidifier:

[0028] As attached Figure 2 The dehumidifier structure consists of two parts, the lower part is equipped with air filter, refrigeration coil, condenser 8, dry air blower 7, base, water tray, refrigeration pipes and refrigeration valves, etc., and the upper part is equipped with condensing fan 9, regeneration electric heater and regeneration fan 3. The dehumidification wheel 4 occupies the upper and lower parts, and the refrigeration compressor 10 is installed on the top of the lower structure box. There is a junction box on the top of the dehumidifier to facilitate the connection of various cables on site.

[0029] The dehumidifier box is composed of a main frame and a panel. The main frame frames are connected by a specially designed three-prong connection. The panel is a sandwich structure composed of an upper metal plate and rock wool insulation material in the middle. The panel and the frame assembly are connected by screws and sealed with a rubber sealing strip. All panels can be disassembled and assembled on site. The maintenance panel is made into an open door and connected to the frame assembly with a special hinge and a special door lock for the air conditioner box.

[0030] The frame, panel combination and internal components divide the dehumidifier into three functional sections, namely the air intake, filtration and refrigeration functional sections, the rotary dehumidification functional section and the air supply fan 7, condenser 8 and regeneration heating functional section. The three functional sections are finally fixed on a common base, and the middle seams are sealed with rubber sealing strips.

[0031] The base of the dehumidifier is formed by bending thick steel plates and bolting them together, and a lifting mechanism is provided on the base. The condensate water receiving tray is installed on the base. The specially designed marine receiving tray is welded from stainless steel plates with a drainage slope, and the receiving tray is enlarged and deepened. Because the installation position of the dehumidifier cannot drain the condensate, a condensate drainage pump is installed inside the receiving tray to drain the condensate to the top of the regeneration wind horizontal drainage pipe, and spray it into the regeneration wind exhaust pipe in the form of mist through a special nozzle, and then be discharged to the outside of the cabin along with the regeneration wind.

[0032] The main components, such as the filter, evaporator 2, condenser 8, dehumidification wheel 4, and electric heater can be pulled in and out from the side of the dehumidifier for easy maintenance and replacement. The above components are equipped with specially designed tracks inside the dehumidifier. The upper and lower slide rails of the dehumidification wheel 4 are equipped with multiple rolling bearings, which can be easily pulled out. There is a sponge seal between the wheel frame and the upper and lower slide rails.

[0033] Specifically, the application of low temperature regeneration polymer dehumidification wheel 4 is:

[0034] The dehumidification wheel 4 used in the utility model is different from the traditional molecular sieve wheel which requires a high regeneration temperature and a higher dry air outlet temperature. The high-molecular dehumidification wheel 4 with low-temperature regeneration only needs a maximum regeneration temperature of 70°C, which is more than 60% energy-saving compared with the regeneration temperature of 140°C of the traditional molecular sieve wheel. The polymer wheel, the adsorption material is a wet desorption polymer adsorption material composed of an organic polymer. The polymer adsorption material has extremely high moisture absorption and desorption performance, is not deliquescent, has a long life, and can be regenerated at low temperatures. Through adsorption, water molecules are absorbed by the polymer, and the polymer chain expands to retain a large amount of water. During desorption, water vapor is released, and the polymer chain shrinks to restore the adsorption capacity again.

[0035] Specific, refrigeration condensation heat recovery technology:

[0036] To further save energy, the heat released by the condenser 8 of the refrigeration and dehumidification system is recovered as a heat source for preheating the regeneration gas. Principle: The outdoor fresh air first passes through the heat exchanger of the condenser 8, absorbs the condensation heat and heats up. A part of the hot air is discharged to the outside of the cabin through the condensing fan 9, and another part of the hot air (the air conditioning flow is the same as the rotor regeneration air flow) is sucked into the rotor regeneration fan 3, and is reheated by the regeneration electric heater to reach the regeneration set temperature. In this way, the regeneration system can recover part of the condensation heat, thereby reducing the power input of the electric heater.

[0037] Specifically, DC variable frequency condensing fan 9:

[0038] In order to recover the condensation heat to the maximum extent, the condensing fan 9 is designed as a DC variable frequency fan, and the fan speed can be automatically adjusted according to the condensing pressure to achieve the set condensing temperature and the air outlet temperature of the condenser 8. The regeneration heater 5 is controlled by a thyristor, with multi-level energy regulation, and the regeneration temperature setting value is based on the change of ambient temperature.

[0039] Specifically, automatic energy regulation of the refrigeration system:

[0040] This utility model dehumidifier unit adopts a fully enclosed refrigeration compressor 10. The compressor 10 body has no energy regulation function. However, the dehumidifier operates all year round. The wet load of the cargo hold is small in the transition season and winter, and the required refrigeration capacity is also small. In addition, in order to prevent the evaporator 2 from frosting in the low temperature season and affecting the ventilation and dehumidification effect, it is necessary to perform energy regulation control on the refrigeration system. The utility model designs an energy regulation valve for hot gas bypass in the refrigeration system. The valve opening degree is controlled by the preset evaporation pressure. When the evaporation pressure is lower than the set value, the energy regulation valve opens, bypassing part of the high-temperature gas exhausted by the compressor 10 to the inlet of the evaporator 2 and mixing with the refrigerant at the outlet of the expansion valve to increase the temperature of the evaporator 2, thereby achieving the energy regulation function of the compressor 10.

[0041] Specific, specially designed dehumidifier automatic control system:

[0042] The dehumidifier automatic control system is specially designed according to the dehumidification requirements of pulp boats. The automatic control system consists of a PLC controller, pressure sensor, temperature sensor, humidity sensor and necessary low-voltage electrical components, and has the following functions and control logic:

[0043] 1. Function switch

[0044] Manual dehumidification mode and automatic dehumidification mode can be selected. In manual mode, you can manually switch between single refrigeration dehumidification, single rotor dehumidification and combined dehumidification; in automatic mode, the PLC can automatically switch between three air dehumidification modes according to the ambient temperature, automatically set the air supply dew point temperature, automatically set the rotor regeneration temperature, and automatically control the condensing fan 9 speed and the regeneration electric heater power, and automatically control the start and stop of the refrigeration compressor 10.

[0045] 2. Automatic dehumidification adjustment control logic

[0046] In automatic mode, the PLC controller automatically detects the ambient temperature (fresh air temperature), and automatically changes the supply air dew point setting value and the regeneration temperature setting value according to the ambient temperature (the difference between the return air dew point and the ambient temperature can be manually preset), and then the combined mode dehumidification function is started. At the same time, the PLC automatically tracks the supply air dew point temperature, supply air temperature, return air temperature, return air humidity, refrigerant low pressure, refrigerant high pressure, condenser 8 outlet air temperature, regeneration temperature and other parameters. The speed of the condensing fan 9 automatically changes according to the condensing pressure to achieve a relatively stable condensing pressure value. The electric heater is controlled by a thyristor, and the input power is controlled by the regeneration temperature setting value. When the return air dew point temperature reaches the set value, the regeneration electric heating input power decreases until the heating stops, and the rotary dehumidification function stops. Next, the refrigeration compressor 10 stops and the dehumidification function stops.

[0047] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low dew point dehumidifier unit for a pulp transport ship, characterized in that: The invention comprises a fresh air subsystem and a return air subsystem, wherein the fresh air subsystem and the return air subsystem both pass through the same dehumidification wheel (4), the fresh air subsystem comprises a condenser (8), a regeneration filter (6), a regeneration heater (5), the dehumidification wheel (4), and a regeneration fan (3) which are sequentially arranged along the fresh air transmission path, and the return air subsystem comprises a primary filter (1), an evaporator (2), the dehumidification wheel (4), and a blower (7) which are sequentially arranged along the return air transmission path.

2. A low dew point dehumidifier unit for a pulp transport ship according to claim 1, characterized in that: The pipeline between the condenser (8) and the regeneration filter (6) is further connected to a pipeline leading to a condensing fan (9).

3. A low dew point dehumidifier unit for a pulp transport ship according to claim 2, characterized in that: The dehumidifier casing is composed of an upper and lower structural casing, wherein the condenser (8), the air blower (7), the evaporator (2), and the primary filter (1) are located in the lower structural casing, the condensing fan (9), the regeneration filter (6), and the regeneration heater (5) are located in the upper structural casing, the dehumidification wheel (4) occupies the upper and lower structural casings, and the regeneration fan (3) and the compressor (10) are located on the top of the lower structural casing.

4. A low dew point dehumidifier unit for a pulp transport ship according to claim 3, characterized in that: Temperature sensors are provided at the inlet of the primary filter (1), between the evaporator (2) and the dehumidification wheel (4), between the dehumidification wheel (4) and the blower (7), at the outlet of the blower (7), at the inlet of the condenser (8), between the regeneration filter (6) and the dehumidification wheel (4), and between the dehumidification wheel (4) and the regeneration blower (3); dew point temperature sensors are provided at the inlet of the primary filter (1) and at the outlet of the blower (7); pressure sensors are provided at the inlet and outlet of the compressor (10); and an over-temperature switch is provided between the regeneration filter (6) and the regeneration heater (5).

5. A low dew point dehumidifier unit for a pulp transport ship according to claim 4, characterized in that: The automatic control system is composed of a PLC controller, the pressure sensor, the temperature sensor, the humidity sensor and low-voltage electrical components.

6. A low dew point dehumidifier unit for a pulp transport ship according to claim 3, characterized in that: The evaporator (2) and the condenser (8) are further connected to an expansion valve and the compressor (10) to form a refrigeration subsystem.

7. A low dew point dehumidifier unit for a pulp transport ship according to claim 6, characterized in that: The pipeline between the evaporator (2) and the expansion valve and the pipeline between the condenser (8) and the compressor (10) are further connected with a hot gas bypass valve.

8. A low dew point dehumidifier unit for a pulp transport ship according to claim 3, characterized in that: The dehumidifier case includes a main frame and a panel. The frames of the main frame are connected by a three-prong connection. The panel is a sandwich structure composed of an upper metal plate and rock wool insulation material in the middle. The panel and the frame assembly are connected by screws and sealed with a rubber sealing strip.

9. A low dew point dehumidifier unit for a pulp transport ship according to claim 3, characterized in that: The condensing fan (9) adopts a DC variable frequency fan, and the fan speed can be automatically adjusted according to the condensing pressure to achieve the set condensing temperature and the air outlet temperature of the condenser (8).

10. A low dew point dehumidifier unit for a pulp transport ship according to claim 3, characterized in that: The regeneration heater (5) is controlled by a thyristor and has multi-stage energy regulation, and the regeneration temperature setting value tracks the change of the ambient temperature.

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