(593e) Improvement of Reformer Section Performance with Poor Feed Gas Quality: Case Study

Reformers are very critical equipment in the production of synthesis gas. Synthesis gas is an important feedstock for many processes like ammonia, methanol, oxo alcohols and also for hydrogen. Operating the reformers at its highest efficiency with equipment integrity is key to have the maximum productivity from reforming section. Methanol and Oxo alcohols processes require synthesis gas with lower hydrogen to carbon monoxide ratio than that of ammonia process. Industrial processes that require lower hydrogen to carbon monoxide ratio will have either different or complex configuration of reforming section with harsh operating conditions and additional feedstocks like carbon dioxide. For the synthesis gas with lower hydrogen to CO ratio applications, care must be taken during the concept and design phase of reforming section, otherwise, modification of the existing reforming section for the lower H2 to Co ratio synthesis gas, will lead into really complex operation. In this paper, various aspects that need to be considered and studied thoroughly while modifying the existing reformer to get lower H2 to CO mole ratio synthesis gas.

Most of the reformers use natural gas as a feed gas for the reforming. The reforming process uses steam as another feed additive to reform the natural gas containing hydrocarbons to produce hydrogen and carbon monoxide. A typical H2 to CO mole ratio in the pure steam reforming process is around 3. In order to get lower ratio of hydrogen and carbon monoxide, carbon dioxide will also be added to reformer feed to convert CO2 to CO using reverse water gas shift reaction in the reformer. With this, higher CO with lower H2 is produced, and resulting lower ratio.

In this paper, a detailed analysis of existing steam methane reformer has been carried to revamp it to produce lower H2 to CO ratio. The objective of the study is in two steps. 1. Minimum capex 2. Minimum ratio to be achieved. This study’s first step has been implemented with minimum capex and 10% lower ratio reduction. Operating window of the reforming has also been modified. This has enabled almost 8% higher CO mole flow that has resulted higher downstream production of OXO alcohol. For the minimum hydrogen to CO ratio, it has been required to increase the CO production by almost 30%. This case has been studied using in-house advanced modelling using Aspen Plus. Various options have been developed and each option has been benchmarked with others in terms technical and economically. This case study shows that more than one solution is possible to improve the CO flow, thereby reduce the H2 to CO ratio. At the end, optimum case has been selected based on the technical and economic complexity, and future growth. Using the selected case, it has been showed that 2 MM USD EBITDA improvement with better reformer integrity can be achieved.