The article is devoted to the problem of optimizationOptimization of demulsifierDemulsifier (separator) designDesign, widely used for oil–water emulsion separation in oil and gas industry. The aim of the study is to develop an optimal designDesign of horizontal demulsifierDemulsifier according to the criteria of strength, rigidity and metal consumption. A solid-state model of the demulsifier was built, including parametric modelingModeling of the bottom and support. A composition of five varying parameters was selected and a system of constraints was developed to formulate optimizationOptimization problems. A research plan was developed, including 16 experiments for the demulsifierDemulsifier bottom and 27 experiments for the demulsifier support. The optimizationOptimization problems of the demulsifier bottom and support designs were formulated and solved. As a resultResult, the reduction of metal intensity of the bottom by 134 kg and of the support by 193 kg was achieved.