electrostatic precipitators(ESPs) refurbishment 2

[tinashe8]

can someone help pliz. our ESP's are sturtevant type used for gas cleaning at an old thermal power station. we have a mechanical rectifier driven by a synchronous motor to provide unidirectional current to the electrodes. the mechanical rectifier is fed by a power transformer secondary winding. the primary winding is also connected to a voltage regulator. the mechanical rectifier is of the rotating blade type, rectifies the high tension single phase alternating current output of the main transformer to the unidirectional current required by the precipitator. now the question is we want to use thyristors, what modifications can we do and what equipment do we need to change this existing system or even circuit diagrams or any other possible systems that we can put in place.thanx

 

[7anoter4]

I think will be better purchasing a High Voltage Transformer Rectifier Set as per following link[for instance]:

http://www.powercon.biz/hvr.html

 

[tinashe8]

7anoter4
thanks for the help. can you help me with the specs of the rectifier transformer considering the technical specifications of the voltage regulator below.

OUTPUT VOLTAGE 50KVA at 600V
WINDING Auto
FREQUENCY 50Hz
TYPE R090/150
RATING% 100
INPUT VOLTAGE 380V
OUTPUT VOLTAGE 600V

the precipitator electrodes need about 45KV to 50KV for efficient precipitation.currently the transformer and mechanical rectifier technical parameters are given below:

MAIN TRANSFORMER

TYPE BTH-PLNS
POWER RATING 50KVA
OUTPUT VOLTAGE 60 000V
NO LOAD VOLTAGE 600V
FREQUENCY 50Hz
IMPEDENCE VOLTS 12.5%
TOTAL WEIGHT 1.1 tonnes

MECHANICAL RECTIFIER
TYPE 2A Form A
MAX INPUT VOLTAGE 60KV
CURRENT 500mA
POWER RATING 50KVA

Your help is greatly appreciated, thanks so much.

 

[Skogsgurra]

I do not think that you need to throw out anything but the rotating rectifier. Not if you do not want to implement things lika fast adaptive control near flash-over limit, which needs a fast voltage controller and, therefore, a thyristor controller.

If that is not the case, I would buy a HV rectifier stack/bridge - depending on how your HV transformer is wound - and keep the autotransformer for voltage control.

If you want to apply adaptive control, that is also possible even if you keep the autotransformer for voltage control. The trick is to slowly adjust the voltage until a flash-over occurs and the quickly quench the flash-over with a simple thyristor ON/OFF "contactor" at the same time as you reduce voltage one or two percent. You have then found the optimum operating point and can run there either until a new flash-over occurs (temperature change or othe gas) or until a set time period, usually 15 minutes or som has elapsed. You then increase voltage carefully until there is a new flash-over.

Simple and efficient. Google for more details.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[tinashe8]

thanks skogsgurra.