Changing default queue to other Broadcasting event

I'm trying to change default queue to another queue of broadcasting event but not work.

I'm tried following instruction from here. Add public $broadcastQueue = 'exports'; but its still running on default queue.

I'm using laravel 5.8. Here is my code.

My controller:

$paramRequest = $request->input();
dispatch(new ProcessExportExcel($paramRequest))->onQueue('exports');
return response()->json('job dispatched to default queue');

My job:

class ProcessExportExcel implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    protected $request;

    public $tries = 3;

    public function __construct($request)
    {
        $this->request = $request;
    }

    public function handle()
    {
        $condition = $this->request;
        // export excel process...
        event(new ExportNotificationEvent($responeData));
    }
}

My event:

class ExportNotificationEvent implements ShouldBroadcast
{
    use Dispatchable, InteractsWithSockets, SerializesModels;

    public $data;

    public $broadcastQueue = 'exports';

    public function broadcastQueue()
    {
        return 'exports';
    }

    public function __construct($data)
    {
        $this->data = $data;
    }

    public function broadcastOn()
    {
        return new Channel('excel-channel.' . $this->data['userId']);
    }

    public function broadcastAs()
    {
        return 'excel-event';
    }
}

via Chebli Mohamed