Export to csv adding html to file

I am trying to export results to a csv file using the following code. The export appears to work, but when I open the file, it contains the html code from the page. Any help is appreciated.

ob_start();
global $wpdb;
$domain = $_SERVER['SERVER_NAME'];
$table = $wpdb->prefix . "qi_project_requests";
$filename = "export.csv";
$sql = $wpdb->get_results("select * from $table");

$header_row = array(
    'Date Submitted',
    'Requestor Name'
);

$data_rows = array();

foreach ($sql as $data) {
    $row = array(
        $data->date,
        $data->rname
    );
    $data_rows[] = $row;
}

$fh = @fopen( 'php://output', 'w' ); 
fprintf( $fh, chr(0xEF) . chr(0xBB) . chr(0xBF) ); 
header( 'Cache-Control: must-revalidate, post-check=0, pre-check=0' ); 
header( 'Content-Description: File Transfer' ); 
header( 'Content-type: text/csv' ); 
header( "Content-Disposition: attachment; filename=$filename" ); 
header( 'Expires: 0' ); 
header( 'Pragma: public' ); 
fputcsv( $fh, $header_row ); 
foreach ( $data_rows as $data_row ) { 
    fputcsv( $fh, $data_row ); 
} 
fclose( $fh ); 

ob_end_flush(); 

die();