zeroBOG™: efficient LNG boil-off gas (BOG) recondensation technology
Sulzer’s zeroBOG is an advanced LNG recondensation technology designed to efficiently recover and reuse boil-off gas (BOG) during LNG transport and terminal operations. Engineered for compactness and reliability, zeroBOG enables total recondensation with proven performance across marine and offshore applications.
Compact & reduced investment
Up to 5 times smaller than traditional units, saving space and reducing costs
Fast & flexible installation
Modular design allows fast assembly on new or existing vessels
Easy, reliable operation
Self-regulating system ensures efficient performance with minimal effort
Main benefits
Compact and reduced investment costs zeroBOG design is typically 5 times smaller than traditional BOG recondensers
Fast installation Supplied as a modular solution, allowing quick assembly and seamless installation on new ships or during retrofit of existing vessels
Ease of operation The self-regulating system and simplified control scheme make the unit easy to operate
Key characteristics
Compact inline condensation system: Offering high operational stability and flexibility for typically non-stable BOG flow rates
Lowest pressure drop <0.5 bar: Making it less sensitive to tilt and motion conditions, ideal for offshore applications such as floating storage and regasification units (FSRU)
Minimal design margin requirements: Use of Sulzer’s proprietary internals design minimizes the margins used to compensate for maldistribution of liquid and gas in offshore applications
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GT‑DWC is a unique distillation technique called dividing wall column, that produces three or more purified products in a single tower that otherwise in conventional way is done by 2-3 columns in series.
A vertical wall splits typically the mid‑section into two functional zones so the column can pre‑fractionate the feed on one side while the other side refines the middle cut (heart‑cut) from the top and the bottom cuts. Compared with a conventional in-series distillation columns, this integrated column reduces investment by half of the equipment count, and its internal arrangement reduces remixing that lower the utility consumption as well.
When comparing with the normal column with a side draw, GT-DWC produces the heart‑cut where it is most concentrated with contamination from top & bottom products, and achieves the same (or better) product specs as by the multi-column system.
A two‑column sequence inevitably wastes duty by splitting and then remixing components between shells, causing thermal inefficiency that drives up utility consumptions for reboiling and condensing. GT‑DWC® consolidates that work inside one shell, so the separation is done once without such thermal inefficiency, with one reboiler and one condenser. That means fewer separation efficiency losses, lower internal flows, and smaller overall duty. Where applicable, GT-DWC typically provide 20-30% energy saving comparing with two-column system with the same or better product separation quality.
Yes. GT‑DWC is often a revamp enabler because it replaces two columns with one shell, freeing plot space and reducing energy consumption. It can also be applied for revamping an existing column with sidedraw to greatly improve the middle heartcut purity/quality that benefit its value and downstream units. Sulzer high-efficiency tower internals and proprietary DWC design are key to guarantee the success of the revamp. Dynamic simulation is used to validate start‑up/shutdown procedures as well as the feed variation to prove controllability within your existing utility envelope.
Sulzer supplies the full set of trays or structured packings, along with distributors, collectors, and when needed, custom wall hardware. The internals are engineered to maintain pressure balance and uniform liquid/vapor distribution on both sides of the wall—this is critical to prevent maldistribution, channeling, or cross‑leakage that can degrade efficiency. Selection (trays vs. packing) depends on capacity, turndown, fouling tendency, and pressure drop targets; our design team sizes distributors/redistributors and sealing elements to keep performance stable across the operating range.
Yes. A single shell creates a clean condenser ↔ reboiler pairing that a heat pump can bridge: the overhead releases heat while condensing; VoltaSplit™ lifts that heat to the reboiler temperature replacing a large share of steam with electricity and reusing condenser heat that would otherwise be rejected.
GT‑DWC excels when there is a meaningful middle cut (heart‑cut) to recover, and when the alternative would be a two‑column arrangement. Typical examples include aromatics heart‑cuts, naphtha splitter, reformate splitter, iso/normal-separation column, and light/medium hydrocarbon fractionations where three product slates are needed. As a rule of thumb, if your feed has a clear light, middle, and heavy region—and the middle product purity/yield matters—GT‑DWC is a strong candidate.
We pair a standard temperature/reflux control structure with additional loops to maintain vapor/liquid splits around the dividing wall. It ensures high controllability, and robust operation even facing the feed variation. Dynamic simulation is used to test disturbances (feed swings, utility changes) and to finalize startup/shutdown sequences before commissioning.
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