Hydrogen and Carbon Monoxide Production Technology
At present, hydrogen is being produced from light hydrocarbon, such as natural gas, LPG, naphtha, etc. as feedstock for consumers in various capacities, for example production at a few hundred normal cubic meters per hour for consumer such as semi-conductor industry, pharmaceutical industry, etc. and production at over 200,000 normal cubic meters per hour per unit for hydrodesulphurization units in the oil refinery.
The production process of hydrogen from light hydrocarbon is composed of four steps: the first step is pre-treatment of raw materials to remove impurities, such as sulphur compounds contained in the feedstock; the second step is production of raw synthesis gas mainly composed of hydrogen and carbon monoxide (CO) by steam reforming reactions of feedstock hydrocarbon; the third step is (when hydrogen is required as the final product) reaction of CO in the raw synthesis gas with steam (CO shift reaction) to convert the majority of CO into hydrogen to increase the hydrogen concentration and the final step is introduction of hydrogen-rich raw synthesis gas into the Pressure Swing Adsorption (PSA) unit to remove CO2, CO by adsorption and to obtain high-purity hydrogen with purity over 99.9% as final product. The core of hydrogen production technology is the steam reforming process that must be very reliable as it requires reactions at high temperatures of 800°C to 950°C.
High-purity CO can also be produced from raw synthesis gas produced by the steam reforming by applying purification and separation technologies of CO, such as cryogenic separation, CO PSA, or CO membrane separation. CO is an important substance in the chemical industry as secondary feedstock for acetic acid production by methanol carbonylation process, phosgene production, formic acid production, and so on.
The hydrogen and CO production technology offered by Chiyoda was originally developed and commercialized by Haldor Topsoe, Denmark, and is now adopted many numbers in different countries all over the world. Since 1954, Chiyoda has designed and constructed many hydrogen production plants in and outside of Japan based on Topsoe's technology. Topsoe's latest hydrogen production technology has the following features:
- High energy efficiency
- Feedstock flexibility
- Tailor-made and flexible design
- High on-stream availability
- Safe and reliable operation
- Low investment cost
To demonstrate aforementioned features, Topsoe is in possession of a Side-fired Tubular Steam Reformer that allows adoption of uniform and higher heat flux, which eventually results in less required number of catalyst tube and expectation of longer life of catalyst tube, and also allows safe and reliable operation as there is no chance of burner flame impingement to the catalyst tubes. In addition to abovementioned fired heater type steam reformer technology, Topsoe is also in possession of 2 types of heat exchanger type steam reformer, one technology is to utilizes the sensible heat of combustion flue gas as heat source for reaction (HTCR: Haldor Topsoe Convection Reformer) and the other one is to utilize the sensible heat of the high temperature process gas as heat source for reaction (HTER: Haldor Topsoe Exchange Reformer).
Commercial plants using HTCR and HTER technologies are already in operation all over the world. Chiyoda is pleased to offer to clients the most suitable reforming technologies from abovementioned many options taking the capacity of the plant and other specific requirement by client into account.
Further, Chiyoda is able to offer pre-reforming technology, which is an adiabatic reformers to be installed at up-stream of abovementioned steam reformer.