Hydrogen sulfide is a chemical compound with the molecular formula H2S. H2S is a colorless toxic gas with an extreme rotten egg odor. Humans can normally detect the odor of the compound at 0.0047 ppm. A single breath at 1000 ppm is lethal. The need to control or remove hydrogen sulfide to safe levels is necessary in all types of industries and applications, but is particularly necessary for the hydrocarbon processing industry. In addition to the safety concerns for plant personnel and operators, H2S removal is required for corrosion control due to the highly corrosive of the compound to pipelines, equipment and downstream processes.
Hydrogen sulfide removal technologies or processes can be classified according to mass of H2S to be removed per day (lbs of H2S per day). As a general rule, H2S removal up to 1,000 lbs per day should consider the use of a fixed bed type scavenger/adsorbent media. A requirement that exceeds this rate of H2S per day would need to consider other processes.
Chemical Products' SULFURTRAP® would be categorized as a fixed bed H2S scavenger. H2S Scavenger can be futher classified as either (1) liquid scavenger or (2) fixed bed scavenger. Both types are treatment options for low temperautre H2S removal from sour hydrocarbon. Liquid H2S scavengers have been used for many years for low-pressure, low-sulfur gas wells. Today, liquid scavenger is being replaced by fixed bed H2S removal media due to the many advantages they present over their liquid scavenger counterparts.
Liquid scavenger is typically supplied in drums or totes, and work by pumping the scavenger liquid directly into the sour gas pipeline. When the liquid scavenger runs out, the empty drum must be replaced with fresh chemical. One of the disadvantages of the chemical is the high treating cost. Operating costs (OPEX) can run as much as 10 times or more than fixed-bed scavengers. The reason the cost difference is so great is that H2S concentrations and gas flow rates fluctuate, but the liquid scavenger pump is normally pre-set to treat the maximum expected H2S concentration. When H2S levels drop, or flow rate decreases, the pump continues pumping the same amount of liquid. This overuse of chemical leads to much higher chemicalo cost. Liquid scavenger is hazardous and difficult to safely dispose. Lastly, liquid scavenger being used for H2S removal have also been proven to form solids that deposit in pipelines, valves and tanks leading to additional costs and headaches for downstream processors.
Conversely, fixed bed hydrogen sulfide removal systems such as SULFURTRAP® offer lower treating costs and form zero by-products or side reactions. A clean, simple process for selective H2S removal. Fixed bed hydrogen sulfide removal media works by passing the sour gas stream through a fixed bed of solid media in a vertical vessel. Fixed bed systems such as SULFURTRAP® can handle fluctuations in flow rate and H2S concentration with no change in performance or the need to “add” chemical, thus lowering operating costs when compared to liquid scavenger.
Fixed bed H2S removal systems are also capable of handling much larger volumes of H2S per day than liquid scavenger systems. Liquid scavenger can typically only treat up to 55 lbs H2S per day where fixed bed media, such as SULFURTRAP™ can economically handle up to 0.5 ton per day.
The choice between these two classes of hydrogen sulfide removal types may seem clear, but are all fixed bed H2S removal technologies alike?
Yes and no.
Many fixed bed products on the market only work in anaerobic, water saturated gas environments and can be extremely difficult to remove from the treating equipment. Spent media caking and agglomeration of certain products can not only lead to an increase in pressure drop, but also pose safety concerns to operators and plant personnel with regard to diffulty of media changeout/replacement. In these instances, potentially dangerous methods to loosen or break the caked, spent material out of the equipment must be employed. Thus leading to more downtime and higher replacment costs.
A solution is finally available…
SULFURTRAP® by Chemical Products Industries, Inc. is the next generation in fixed bed H2S removal technology. SULFURTRAP® easily removes H2S to <1 ppm, is capable of high sulfur loading capacity and is free-flowing in its used form. Finally,a product that performs as expected, and is both safe and easy to replace.
Call us today for assistance with the design of your next hydrogen sulfide removal project, or for information concerning the replacement of your current H2S scavenger system.