One-step method coal system synthetic natural gas system

The utility model discloses an one-step method coal system synthetic natural gas system, including the rectisol plant's that connects gradually first absorption tower, the shell side or the tube side of first feed gas pre-heater, deep purification desulfurizer, the tube side or the shell side of second feed gas pre-heater, isothermal methanator, the tube side or the shell side of first feed gas pre-heater, the shell side or the tube side of boiler feed water pre-heater, demineralized water pre-heater, condensate separator and rectisol plant's second absorption tower, wherein the shell side or the tube side export of second feed gas pre-heater still pass through adiabatic methanator, steam superheater's shell side or tube side and isothermal methanator's access connection in proper order, isothermal methanator's export is still in proper order through the tube side or the shell side of second feed gas pre-heater, recycle gas compressor and adiabatic methanator's access connection. The utility model discloses simple structure, the flow is brief, and device operation and investment cost are low, concentrate recuperative heat and the high-quality steam of by-product.