Can I just speed my industrial fan up to make it more powerful?

Most industrial fan motors these days are suitable for speed increase by invertor control. (But beware motors for hazardous areas may not be certified for use with speed control.) However you should be aware of the industrial fan laws because you will get an increase in flow, pressure and power and could overload your motor. You will also need to contact Fans & Blowers Ltd Technical Sales department to ensure the centrifugal fan is mechanically suitable.