A solvent is dispersed into a natural gas feed at a solvent injection point to produce a mixed feed. The mixed feed contains heavy components with a potentially fouling portion that can cause obstructions in a heat exchanger. A fluid injection system can inject the solvent intermittently, for instance, based on an amount of accumulation or expected accumulation of heavy component solids in the heat exchanger. The solvent prevents the potentially fouling portion of the heavy components from freezing, melts or dissolves the accumulation, and reduces the obstructions in the heat exchanger. The fluid injection system includes a solvent supply, an optional atomizer, an injection controller, optionally one or more sensors, and/or optionally a heater. The solvent injection system can disperse the solvent onto a flow surface for the natural gas feed and/or mixed feed to form a solvent film which further reduces heavy component solids.

A system and method for producing an LNG product stream to provide fuel to generators, as an alternative to diesel, to power drilling and other equipment. Using sales gas from a natural gas/NGL plant containing less than 95% methane as a feed stream, production of LNG having 95% or more methane in quantities of 100,000 GPD or more LNG product are achievable with the system and method. The system and method preferably combine use of strategic heat exchange between the feed and a nitrogen-methane flash vapor stream and other streams within the LNG processing system without requiring heat exchange with process streams in the natural gas/NGL plant and a rectifier column that uses an internal knockback condenser and does not require a reboiler to remove heavier components from the sales gas feed.

A hybrid process of air separation and gas liquefaction, including dividing a compressed multicomponent refrigerant stream into a first portion and a second portion, introducing the first portion into a gas liquefaction system, thereby producing a first multicomponent refrigerant return stream, and introducing the second portion into an air separation system, thereby producing a second multicomponent refrigerant return stream. Wherein the first multicomponent refrigerant return stream and the second multicomponent refrigerant return are recompressed in a common compression system, thereby producing the compressed multicomponent refrigerant stream.

A single compressor is used to separately compress permeate from cascaded first and second gas separation membrane-based separation units and residue from a fourth gas separation membrane-based separation unit in order to avoid too high a CO2 partial pressure in the compressed permeate. After the permeates from the first and second stages are compressed, the compressed stream is fed to a third gas separation membrane-based separation unit.

A system for separating olefinic hydrocarbon and hydrogen in an effluent fluid stream from a dehydrogenation reactor includes a heat exchanger that receives and partially condenses the effluent fluid stream so that a mixed phase effluent stream is formed. A primary separation device receives and separates the mixed phase effluent stream into a primary vapor stream and a primary liquid product stream. A heat exchanger receives and partially condenses the primary vapor stream so that a mixed phase primary stream is formed. A secondary separation device receives and separates the mixed phase primary stream into a secondary vapor stream and a secondary liquid product stream. A heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the effluent fluid stream and a heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the primary vapor stream. A mixed refrigerant compression system provides refrigerant to a heat exchanger to provide refrigeration.

Methods and systems are disclosed to compress raw, liquids-rich natural gas to high pressures while removing heavier hydrocarbons and water through inter-stage gas processing. Some variations provide a method for purifying and compressing natural gas, comprising: conveying a methane-containing input stream to first-compression stages; generating an initial compressed gas stream at a first pressure; conveying the initial compressed gas stream to a low-temperature separation sub-system configured to remove liquid contaminants, thereby generating an intermediate compressed gas stream at a second pressure; conveying the intermediate compressed gas stream to second-compression stages, to generate a compressed gas product stream at a third pressure; recovering purified and compressed natural gas; and feeding the compressed gas product stream into a mobile container. The sub-systems are preferably integrated into a single unit. The invention solves several problems associated with processing and transporting raw natural gas from initial production locations to end markets for final use.

A method is disclosed for start-up of a system for liquefying a feed gas stream comprising natural gas. The system has a feed gas compression and expansion loop, and a refrigerant system comprising a primary cooling loop and a sub-cooling loop. The feed gas compression and expansion loop is started up. The refrigerant system is pressurized. Circulation in the primary cooling loop is started and established. Circulation in the sub-cooling loop is started and established. A flow rate of the feed gas stream and circulation rates of the primary cooling loop and the sub-cooling loop are ramped up.

A method for recovering associated gaseous hydrocarbons from a well for producing liquid hydrocarbons, the method comprising (i) providing gaseous hydrocarbons from a hydrocarbon well; (ii) providing a cryogenic liquid from an air separation unit or an associated nitrogen liquefaction facility within proximity of the hydrocarbon well; (iii) liquefying the gaseous hydrocarbons at a hydrocarbon liquefaction facility within proximity to the hydrocarbon well to thereby produce a liquefied hydrocarbon gas, where heat associated with the gaseous hydrocarbons is transferred to the cryogenic liquid; and (iv) transferring the liquefied hydrocarbon gas to an air separation unit or nitrogen liquefaction facility.

A system for separating olefinic hydrocarbon and hydrogen in an effluent fluid stream from a dehydrogenation reactor includes a heat exchanger that receives and partially condenses the effluent fluid stream so that a mixed phase effluent stream is formed. A primary separation device receives and separates the mixed phase effluent stream into a primary vapor stream and a primary liquid product stream. A heat exchanger receives and partially condenses the primary vapor stream so that a mixed phase primary stream is formed. A secondary separation device receives and separates the mixed phase primary stream into a secondary vapor stream and a secondary liquid product stream. A heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the effluent fluid stream and a heat exchanger receives and warms the secondary vapor stream to provide refrigeration for partially condensing the primary vapor stream. A mixed refrigerant compression system provides refrigerant to a heat exchanger to provide refrigeration

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs a nitrogen-based refrigerant, at least one heat exchanger, three turbine/expanders and two or more refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas containing feed stream but colder than −15° C.