For most CO shift systems, catalyst selection starts with the process temperature, feed composition, steam availability, and the required outlet CO level. High-temperature shift (HTS) catalysts are commonly iron-based and operate at higher temperatures, while low-temperature shift (LTS) catalysts are commonly copper-based and operate at lower temperatures to support deeper CO conversion. In many hydrogen and syngas plants, the two stages are used in sequence, but the appropriate arrangement depends on the process design and operating conditions.
This guide explains the differences between HTS and LTS catalysts, how to match catalyst type to an application, and what information to prepare when evaluating products or suppliers. Operating ranges below are indicative industry ranges, not guaranteed specifications; always confirm them against the catalyst supplier’s technical documentation and the plant design.
This guide is intended for process engineers, project teams, plant operators, and procurement professionals evaluating CO shift catalysts for new units or catalyst replacement. It is relevant to hydrogen production, ammonia synthesis gas, methanol feed gas, and other processes where carbon monoxide reacts with steam to form carbon dioxide and hydrogen. The exact process configuration and gas composition vary, so selection should be verified for the individual plant.
Buyers comparing quotations can also use the guide to align technical scope before commercial evaluation. A catalyst price is meaningful only when the catalyst type, quantity basis, loading requirements, delivery terms, and technical support included are clear. For revamps or replacement projects, existing reactor and operating data are especially important.
The water-gas shift reaction converts carbon monoxide and steam into carbon dioxide and hydrogen: CO + H2O ⇌ CO2 + H2. The reaction releases heat, and the equilibrium generally favors greater CO conversion at lower temperatures. A shift catalyst helps the reaction reach equilibrium more quickly; it does not change the equilibrium itself.
HTS and LTS catalysts address different parts of the process. An HTS bed can handle the hotter gas leaving upstream reforming or gasification steps, while an LTS bed can provide further CO conversion after gas cooling. Where both stages are installed, interstage cooling and gas conditioning are part of the process design, not optional details to be decided from catalyst type alone.
HTS catalysts are commonly based on iron oxide, with promoters and formulation details varying by product. An indicative operating range is approximately 310–450°C, but actual allowable inlet and outlet temperatures depend on the catalyst and reactor design. HTS is often selected for the hotter, higher-CO portion of a shift process.
When evaluating an HTS product, review its specified startup and reduction procedures, operating temperature limits, pressure-drop expectations, and tolerance for the anticipated feed composition. Confirm whether the catalyst is supplied in a form requiring activation or reduction before operation. Do not assume that two iron-based products have identical loading, conditioning, or operating requirements.
LTS catalysts are commonly based on copper, zinc oxide, and alumina. An indicative operating range is approximately 190–250°C, with product-specific limits and recommended startup procedures. The lower-temperature stage is used when the process needs additional CO conversion after the gas has been cooled and conditioned.
Copper-based catalysts can be sensitive to contaminants, including sulfur compounds, and may also be affected by unsuitable thermal or operating conditions. Buyers should confirm feed contaminant limits and required upstream protection with the supplier and process licensor. The catalyst’s recommended startup, shutdown, and temperature-control procedures should be treated as part of the selection.
First determine whether the project requires an HTS bed, an LTS bed, or a staged HTS–LTS arrangement. Review the gas source, existing reactor sequence, interstage cooling, and the target CO concentration at each process boundary. A catalyst cannot be selected reliably from the product name or application label alone.
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For a replacement, compare current operating data with the original design basis, including changes in feed composition, throughput, steam supply, and pressure drop. If a unit has experienced performance changes, investigate possible process, mechanical, or contamination causes before assuming that a different catalyst formulation will solve the problem. Share both normal and relevant upset conditions during technical discussions.
Provide the supplier with gas composition, expected operating range, steam availability, pressure, flow rate, and reactor dimensions where available. Include known sulfur or other contaminant levels, as well as details of upstream guard beds or cleanup steps. These inputs help determine whether a proposed product is technically compatible and what operating restrictions may apply.
Also review the plant’s constraints on pressure drop, bed loading, heat management, and turnaround schedule. The exothermic shift reaction can create temperature rises through the catalyst bed, so inlet temperature alone is not sufficient for evaluating operating suitability. Ask the supplier to clarify which values are design assumptions and which are product limits.
Ask suppliers to distinguish guaranteed product properties from typical or informational values. Request the relevant technical data sheet and safety documentation, and check that the quoted product identity matches the intended process stage. Where a change from the current catalyst is proposed, ask what process or reactor modifications, if any, are assumed.
CO shift catalyst pricing depends on factors such as catalyst formulation, order quantity, packaging, production schedule, and delivery requirements. Minimum order quantities and lead times are supplier- and project-specific, so buyers should request current terms rather than rely on general market estimates. For shutdown planning, clarify the required delivery date and allow time for technical review, transport, and site receiving arrangements.
When comparing offers, use a consistent scope: identify the catalyst stage, quantity and measurement basis, packaging, destination, delivery terms, technical documents, and any support included. A lower unit price may not represent equivalent scope if product specifications or delivery conditions differ. Procurement teams should coordinate the commercial comparison with engineering approval.
A suitable supplier should be able to explain the intended application of the quoted catalyst, provide relevant technical documentation, and identify the operating information needed to assess fit. Evaluate responsiveness to technical questions, clarity around product limits, packaging and logistics, and the supplier’s ability to support project-specific requirements. Do not treat general performance statements as a substitute for a documented product specification.
At SCST, we support B2B buyers evaluating CO shift catalyst requirements for industrial projects. To begin a technical discussion, provide the process stage, gas composition, operating temperature and pressure, steam conditions, reactor information, target outlet conditions, and required delivery schedule. We can then review the scope with you and clarify the information needed for a product and commercial proposal.
The right CO shift catalyst depends on the process duty: HTS commonly uses iron-based catalyst at higher temperatures, while LTS commonly uses copper-based catalyst at lower temperatures for further CO conversion. The indicative ranges of 310–450°C for HTS and 190–250°C for LTS provide a starting point, not a substitute for product-specific limits or process engineering review. A staged HTS–LTS arrangement may be appropriate, but the plant configuration and gas conditioning determine the final choice.
As a next step, assemble the process data, confirm contaminant controls and reactor constraints, and request a technical specification that matches the intended duty. Then compare supplier documentation, delivery scope, and support alongside price. Contact SCST with your operating conditions and procurement requirements to discuss a suitable CO shift catalyst evaluation.
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