We are interested in reducing treatment load on spent caustic treatment unit. Then we are going to idle visbreacker gasoline treatment process by feeding it to other units. At present we use sweetening process (washing with caustic and converting with Merox) for visbreacker gasoline product. The problem regarding to produced spent caustic as byproduct is unreliable spent caustic treatment process to meet the environmental specs. The alternatives are suggested as follows:
1- introducing to heavy naphtha hydrotreater unit (unifiner)
2- introducing to Kerosene/diesel hydrotreater unit
3- introducing to hydrocracker unit
4- sending to crude storage and refine it again
Would you please explain pros and cons about the abovementioned alternatives? What is the best alternative?