Only Na_3PO_4 is injected into boiler water in EPT, and a few free NaOH is permited to exist, so the value of pH is master of Na_3PO_4 and NaOH together.

• EPT往炉水中只添加Na_3PO_4,且允许有少量游离的氢氧化钠存在,炉水碱度由Na_3PO_4和NaOH共同控制。