Beginning from Spark 3.0, you may use the 

make_interval(years, months, weeks, days, hours, mins, secs)

 function if you want to add intervals using values from other columns.

SELECT

id

, Start_time + make_interval(0, 0, 0, 0, time_zone_offset, 0, 0) AS Local_Start_Time

FROM MyTable

https://stackoverflow.com/questions/60209203/adding-variable-hours-to-timestamp-in-spark-sql