Research of New Cross-Flow Technology with a Gas Heat Carrier for Lignite Pyrolysis.

Abstract

The adaptability of the gas heat carrier cross-flow pyrolysis process to Huolinhe lignite (0–80 mm) and the influence of the temperature of the heat carrier and moisture of the raw materials on the yield and properties of the pyrolysis products were studied using a 30 t/d cross-flow pyrolysis pilot plant with a gas heat carrier. When the temperature of the gas heat carrier was increased from 750 to 850 °C, the volatiles (Vdaf) produced from the char decreased from 16.81 to 10.57%, the yield of tar (Tard) increased from 73.81 to 81.1% of the Gray-King (G-K) tar yield, and the yield of gas decreased from 1312 to 1205 Nm3/t. When the temperature of the gas heat carrier was constant at 850 °C and the moisture content (Mt) of lignite was reduced from 12.49 to 7.14%, the Vdaf of char declined from 10.57 to 6.59%, the yield of gas was reduced from 1205 to 805 Nm3/t, the calorific value of gas increased from 3.88 to 4.68 MJ/m3, and the Tard increased to 81.56% of the G-K tar yield. The light tar content (boiling point below 360 °C) was more than 60%, and the ash content was less than 0.04%. The cross-flow pyrolysis moving bed could effectively treat full-size lignite, afforded continuous and stable operation, and provided a high oil and gas yield, which provides basic data for further industrial design.