The rapid development of large‑scale coal‑chemical industry requires corresponding technical equipment support. In particular, coal‑to‑liquid, methanol, synthetic ammonia and coal‑to‑olefin projects demand a large quantity of heavy‑duty coal‑chemical valves. Among them, coal‑to‑liquid (oil produced by coal liquefaction) is a key newly‑developed technology. The process conditions of direct coal liquefaction units are extremely harsh, imposing stringent requirements on valves. Characterized by flammable medium, high temperature, corrosion and abrasion, coal‑to‑liquid service places high performance requirements on valves.