JPH0465317B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control device that optimally distributes the heat exchange amount of a separate heat pipe, and is applicable to a field where heat exchange of exhaust gas is performed using a plurality of heat exchange means. can be used.

BACKGROUND ART A separate heat pipe is a type of heat exchanger, and is characterized in that an evaporator and a condenser for water, which is a heat exchange medium, are provided separately. A heat pipe system consists of several sets of closed cycle units, each consisting of a separate evaporator and condenser and a circulating water pump connecting them.

The amount of heat exchanged in conventional separate heat pipes is controlled by controlling the heating side gas temperature and controlling the water level in the evaporator, using a circulating water flow rate control valve as the operating end.

Problems to be Solved by the Invention However, in a system consisting of multiple units, even if the external conditions (temperature and flow rate at the inlet of the heating side gas and heated side gas) are constant, there are multiple balance points. do. For example, if the total amount of heat exchanged in a system consisting of three units is, for example, 6, the amount of heat exchanged in each unit may be distributed as ``3:2:1'' or ``2:2:1''.
2" may be distributed. Therefore, conventional systems in which each unit independently operates to achieve a control objective have the following drawbacks.

(1) Some units are operated in areas where control performance is poor, where the amount of heat exchange is too much or too little.

(2) The heating side gas temperature may be cooled too much in the upstream unit, resulting in negative pressure in the downstream unit. In this case, air leakage occurs, resulting in poor heat exchange efficiency and shortened service life due to oxidation within the system.

The present invention has been made in view of the above circumstances, and an object of the present invention is to optimally allocate the heat exchange amount of a separate type heat pipe consisting of a plurality of units.

Means for Solving the Problems According to the present invention, in a separate heat pipe system including a plurality of heat exchange units, each heat exchanger is The optimum distribution amount of the heat exchange amount to the units is calculated, and the heat exchange medium of each unit is finely adjusted to the respective standard flow rate.

Embodiment The drawings show a control system of a control device according to the present invention together with a configuration of a separate heat pipe.

Separate type heat pipe has evaporators 1A, 1
B, each having condensers 2A and 2B, and an evaporator 1
A circulating water pump 3A and a circulating water control valve 4A are provided between A and the condenser 2A, and a circulating water pump 3B and a circulating water control valve 4B are provided between the evaporator 1B and the condenser 2B. In the illustrated example, the B gas is heated by exhaust gas for convenience, but any gas may be used on both the heating side and the heated side. Furthermore, although two units are shown as the closed cycle, three or more units may be used.

Evaporators 1A and 1B are provided with evaporator water level transmitters 5A and 5B, the outputs of which are connected to evaporator water level deviation controllers 7A and 7B together with the outputs of evaporator water level setters 6A and 6B,
These outputs are connected to adders 8A and 8B, respectively. A B gas temperature transmitter 9 and a B gas flow rate transmitter 10 are provided upstream of the B gas duct, and an exhaust gas temperature transmitter 11 and an exhaust gas flow rate transmitter 12 are also provided upstream of the exhaust gas duct. The output of each of these transmitters is connected to a function 13 that calculates the amount of heat exchange required of the heat pipe system. In the illustrated example, transmitters 9, 10, 11,
Although 12 four output signals are used, the present invention is not limited to these as long as the signals can calculate the amount of heat exchange. For example, when applied to a boiler plant, the heat exchange amount can be calculated from the boiler load and exhaust gas temperature. The output of function 13 is function 14A which calculates the reference flow rate for each unit.
and 14B, and these outputs are connected to adder 8
A and 8B are respectively connected.

Function The amount of heat exchange required for the system is determined using the function 13 based on the external conditions of the system, that is, the signals from the B gas temperature transmitter 9, the B gas flow rate transmitter 10, the exhaust gas temperature transmitter 11, and the exhaust gas flow rate transmitter 12. Calculated. The signal from function 13 is used to set the reference flow rate for each unit in functions 14A and 14B. This reference flow rate is determined to prevent each unit from operating in a region with poor controllability or from operating under negative pressure. The optimal reference flow rate for each unit is added by adders 8A and 8B to the signals from the evaporator water level deviation controllers 7A and 7B, which are feedback signals for fine adjustment. The opening degrees of the circulating water control valves 4A and 4B are controlled by the addition signal.

In this example, an example of constant level control is given, but the same applies to outlet exhaust gas temperature control.

Effects of the Invention In a separate heat pipe system that includes multiple heat exchange units, there are multiple balance points, so in a conventional system where each unit operates individually, some units may have poor controllability. However, according to the present invention, the balance point of each unit can be limited to a convenient point for operation, so the above-mentioned drawbacks can be solved. .

Furthermore, since the required amount of heat exchange is calculated from the system external conditions, operating conditions can be changed in advance, and control responsiveness is significantly improved.

[Brief explanation of drawings]

The drawing is a diagram showing a system of a control device according to the present invention together with a configuration of a separate heat pipe. 1A, 1B...Evaporator, 2A, 2B...Condenser, 3A, 3B...Circulating water pump, 4A, 4B...
...Circulating water control pump, 5A, 5B...Evaporator water level transmitter, 6A, 6B...Evaporator water level setting device, 7A, 7B...Evaporator water level deviation controller, 8A, 8B...Adder , 9...B gas temperature transmitter, 10...B gas flow rate transmitter, 11...Exhaust gas temperature transmitter, 12...Exhaust gas flow rate transmitter, 1
3, 14A, 14B...function.

Claims (1)

[Claims] 1. A plurality of heat exchange units each having an evaporator and a condenser arranged separately are provided in the heating side gas duct and the heated side gas duct, and each unit has an evaporator, a condenser, a circulating water pump, and a circulating water flow rate control valve. In the control device configured to individually control the circulating water flow rate control valve in each unit, there is provided a means for calculating the total amount of heat exchanged by each unit based on system external conditions, and a means for calculating the calculated amount of heat exchanged. A control device for a separate type heat pipe, comprising means for adjusting the control system of the circulating water flow rate control valve in each unit by distributing the water in accordance with the optimum operating conditions of each unit.