** Shares of India's Thirumalai Chemicals THRM.NS up 2.6% to 277 rupees
** Tuesday's gains come after co said on Monday it will double production capacity of phthalic anhydride by FY28 and ended session 8% higher
** Phthalic Anhydride is a chemical compound used to make resins, paints and is a key product in co's portfolio
** Co owns a quarter of India's Phthalic Anhydride export market - statement
** Trading vols 683k shares vs 30-day avg of 322k shares
** YTD stock down ~14%
(Reporting by Hritam Mukherjee in Bengaluru)
((Hritam.Mukherjee@thomsonreuters.com;))