Improvement of the adsorption-absorption vapor recovery unit for cleaning the gas-air mixture from volatile organic compounds and hydrogen sulfide when loading naphtha on marine tankers

Abstract

The article proposes the improvement of adsorption and absorption plants for the recovery of naphtha vapors through the use of a sulfur compounds purification unit. This unit allows you to remove environmentally hazardous sulfur components from naphtha vapors, which adversely affect adsorption filters, without increasing the temperature and significant pressure drop of the gas-air mixture. The relevance of the study is due to the fact that marine terminals are objects of significant emissions of hydrocarbons and sulfur compounds. Intensive evaporation of naphtha during the filling process leads to air pollution and loss of valuable product. Vapor recovery units with a desulfurization unit are designed to solve the problem, however, their implementation at loading facilities requires the installation of additional flow stimulators and, as a rule, additional electricity consumption. The main purpose of the study was to find ways to improve environmental safety and improve adsorption and absorption vapor recovery units at existing sea tanker loading facilities, taking into account the current level of their technical equipment. It established that the use of the proposed desulphurization unit makes it possible to expect a reduction in energy consumption due to the absence of flow stimulators (gas blowers), as well as an increase in the operation of adsorption filters by 35-45%. The effectiveness of modeling the purification of low-pressure gas from hydrogen sulfide has been confirmed by studies on a laboratory installation including a desulfurization reactor. Purification of gas from hydrogen sulfide using a chelated iron complex ensures the conversion of hydrogen sulfide into sulfur, while the residual content of hydrogen sulfide can be reduced to less than 1 ppm. The implementation of catalytic purification by a chelated iron complex in a disk film apparatus makes it possible to purify the gas-air mixture from hydrogen sulfide impurities.