The relevance of the research is caused by the need to increase energy efficiency when using hydrocarbons for combined production of chemical products and energy carriers applying gasification technologies. This will allow reducing production costs and expanding the possibilities of gas chemistry. The main aim of the research is to determine the thermodynamic efficiency of partial fuel oxidation reactors, being the part of energychemical plants, by the combined production of energy carriers and synthesis gas. The main attention is paid to the influence of the regime parameters on numerical value of the exergy efficiency. Object of the research is a partial oxidation reactor with a set of auxiliary equipment for providing synthesis gas production. This takes into account the system factor, i. e. parameters of the power system within the framework of which it is planned to build a similar type of power plant. Method: numerical experiment involving traditional approaches to compiling exergy balance of heat and power plants. The authors have used as well the mathematical models developed earlier by them for calculating the parameters of synthesis gas formed at processing hydrocarbon raw materials in flow-through autothermal non-catalytic reactors. Results. The obtained results enable us to choose the most expedient operating parameters of the partial oxidation reactor, which is a part of the energy-chemical plants with the gasification of unstable gas condensate. So the maximum values of exergy efficiency are achieved by using atmospheric air without enrichment with oxygen, both for the case of water vapor supply ( ŋ ex =78-83 %), and for the case without steam supply ( ŋ ex =82-88 %). At the same time, some variants of thermal schemes of energy-chemical plants with fuel gasification in thermodynamic terms can be considered equally effective, and the decision on the amount of water vapor supplied to the reaction zone must meet the requirements for synthesis gas. The choice of working pressure level in the reactor requires additional studies since the evidence of the use of the atmospheric-type reactor is not revealed at this stage of the study.