TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The coal gas is mixed and processed with separating ring coal gas after cooling and degreasing. The coal enters into coal gas separating part. The sewage evaporation system (WG) comprises sewage degassing part S3, sewage softening part, and sewage evaporation part. In sewage degassing part, gas and degassing water are acquired after removing oxygen of sewage containing coal tar. In sewage softening part, hardness of degassing water is reduced to become softened water. In sewage evaporation part, most of softened water is evaporated to acquire steam and concentrated water, such that quantity of concentrated water is smaller than 20% of quantity of sewage containing coal tar. The second steam is used as water steam evaporation agent. The sewage evaporation system also comprises steam overheating part, in which second steam is heated to acquire overheating steam used as evaporation agent water steam. The mixed gas is acquired after mixing mixed part, concentrated water, and overheating steam. The mixed gas is used as evaporation agent steam to enter into sewage gas making part. The concentrated water is removed with independent burning process. The coal gas sequentially passes through steam generator to carry out steam cooling. In sewage evaporation part, steam and concentrated water are acquired using evaporation pressure of 0.15-1.0 MPa (absolute pressure). The weight ratio between concentrated water and sewage containing coal tar is smaller than 0.2. The sewage gas making part has pressure of 0.15-1.0 MPa, temperature of 1000-1450 degrees C, and steam evaporation agent conversion rate of greater than 80%. The operation condition of sewage gas making part includes pressure of 0.15-0.5 MPa, temperature of 1100-1400 degrees C, and steam evaporation agent conversion rate greater than 90%. In the sewage evaporation part, steam and concentrated water are acquired under evaporation pressure of 0.15-0.3 MPa (absolute pressure). The weight ratio between concentrated water and sewage containing coal tar is less than 0.1. The operation condition of sewage gas making part includes pressure of 0.15-0.3 MPa, temperature of 1150-1350 degrees C, and steam evaporation agent conversion rate of greater than 95%. In Lan charcoal screening part, Lan charcoal is separated into large grain size Lan charcoal DLT and small grain size Lan charcoal XLT. At least one part of small grain size Lan charcoal XLT is used as carbon raw material of sewage gas making part. The grain diameter of large grain size Lan charcoal DLT is larger than 5 mm. The grain diameter of small grain size Lan charcoal XLT is larger than 5 mm. In tar fractionation part, coal tar is separated into coal tar distillate so that coal pitch formed component whose routine boiling point is higher than 450 degrees C and at least one part of coal pitch is used as carbon raw material of sewage gas making part. The coal pitch is formed by component whose routine boiling point is higher than 485 degrees C or higher than 515 degrees C.