302 results about "Mixed fuel" patented technology

The application provides a simplified modeling method, device and computer program product of a complex mixed fuel combustion reaction kinetics model. The simplified modeling method comprises the following steps: model coupling, one-time simplification of the model by using an error transmission-based directed relationship diagram method and a species sensitivity analysis method, optimization of the one-time simplified model by taking the optimal pre-exponential factor, temperature index and activation energy of the three-parameter modified Arrhenius equation as optimization objects, and re-simplification of the optimized model. The application adopts a method for directly simplifying a complex model, does not need to artificially disassemble and construct the model, does not need to perform in-depth reaction path analysis, does not need to perform program writing, is suitable for combustion simulation engineering practitioners without a combustion reaction kinetics research foundation, is used to quickly produce a fuel mechanism model, and is reasonably verified.

The invention discloses an amino mixed fuel explosion characteristic visualization and explosion suppression coordinated regulation and control system and method, and the system comprises an explosion suppression device which is disposed in a combustion chamber and is in communication connection with a holographic monitoring device and an explosion overpressure real-time prediction model. A graded explosion suppression scheme is set according to the safety early warning grade, so that active intervention of explosion suppression intensity and mode matched with combustion or explosion development stages with different intensities in the combustion cavity is implemented. Therefore, visualization of the mixed gas combustion and explosion dynamic process under the multi-parameter coupling condition can be achieved, and the comprehensiveness and reliability of combustion and explosion research are remarkably improved; through real-time monitoring and intelligent prediction of the explosion process, the explosion process in the device can be rapidly started, the explosion suppression response can be optimized, the explosion development can be suppressed, the integrity and operation safety of an experiment system can be guaranteed, and the intrinsic safety and the system protection capability of the experiment process can be effectively enhanced.

An ammonia mixed combustion engine 1 that operates by burning ammonia and a hydrocarbon liquid fuel causes a control unit 2 to implement at least one of decrease or increase in an air excess ratio in fuel, advance or retard in injection timing of the liquid fuel, and decrease or increase in injection pressure of the liquid fuel in accordance with increase or decrease in a mixed fuel burning ratio of ammonia in the fuel.

The invention discloses an intelligent prediction method and system for the alkali metal slagging tendency of a biomass gas coupled coal-fired boiler, and relates to the field of slagging tendency prediction.The intelligent prediction method comprises the steps that flue gas temperature data of a target area of a convection heating surface of the boiler is obtained, and the ash content melting characteristic temperature and alkali metal element content data of mixed fuel entering the boiler are obtained; performing physically constrained ash temperature-liquid phase yield adaptive correlation calculation, calculating coupling adhesion force, generating equivalent adhesion strength distribution of particle surfaces, counting particle turbulence collision physical parameters based on the equivalent adhesion strength distribution of the particle surfaces, and judging effective collision adhesion efficiency based on energy competition. The method comprises the following steps: calculating the agglomeration growth rate of ash particles in a flow field, outputting the spatial growth configuration of ash particle aggregates, carrying out macroscopic mechanical characteristic analysis and bridging stability judgment on an accumulation body at the throat part of the dry bottom hopper according to the spatial growth configuration of the ash particle aggregates, and outputting the blockage risk level of the dry bottom hopper, thereby effectively solving the blockage problem of the dry bottom hopper.

The present technology relates to biofuels, and more particularly, to biomass-based diesel from olefin oligomers. Diesel fuels with cetane number of 49 or greater are prepared by blending hydrocarbons produced by olefin oligomerization with renewable diesel, resulting in a blended fuel that has a lower cloud point than the cloud point of the renewable diesel. A different aspect relates to an integrated process for lipid HDO and olefin oligomerization wherein the propane coproduct of lipid HDO is subjected to dehydrogenation to produce a vapor stream having propylene and hydrogen. The propylene is subsequently oligomerized to iso-olefins and the iso-olefins are combined with the lipid feed for hydrogenation in the HDO reactor.

The invention discloses a catalytic porous medium clean combustion reactor for hydrogen-ammonia blended fuel, and relates to the technical field of reactors. The reactor comprises a reactor body, wherein a filtering assembly and a crushing assembly are mounted at the top of the reactor body; a combustion chamber is arranged in the reactor body, a ceramic porous plate is arranged on the combustion chamber, and an air inlet pipe, an air outlet pipe and a catalysis pipe are arranged on one side of the reactor body. A composite crushing structure of primary crushing of the crushing rods and secondary impact of the elastic crushing rods is adopted, and the crushing efficiency is improved by 40% or above compared with a traditional rigid structure; a conical filter screen of the filter assembly is matched with a clamping piece rapid dismounting and mounting mechanism, the screening efficiency is improved by 30%, shutdown is not needed in the impurity recycling process, retention materials can be collected by connecting lead screws between an annular shielding plate of a sliding shielding piece and an upper barrel body and a lower barrel body of a rotary fixing barrel, and the manual maintenance cost is reduced.

The invention provides a cold-state boiler starting combustion control method for a sludge and solid waste collaborative incineration boiler. Whether the feeding rate of ignition fuel, auxiliary solid waste fuel and sludge meets the requirement for safe operation of the boiler or not can be rapidly judged. The method comprises the following steps: 1, obtaining the length, width and height sizes of a hearth and the maximum heating rate of the castable; calculating the total heat exchange area and the total volume of the hearth, the total energy of ignition fuel fed into the hearth during combustion, the temperature rise value of air in the hearth after the ignition fuel is combusted, and the temperature rise value of the castable in unit time; comparing the temperature rise value of the castable in unit time with the maximum temperature rise rate of the castable; 2, calculating smoke components in the hearth when the auxiliary solid waste fuel and the sludge are added, the total energy of mixed fuel fed into the hearth during combustion, the temperature rise value of smoke in the hearth space after the mixed fuel is combusted, and the temperature rise value of the castable in unit time under the condition that the mixed fuel is added; and comparing the temperature rise value of the castable in unit time with the maximum temperature rise rate of the castable.

The present invention discloses a combined quality improvement method for a flue gas modified wheat straw and lignite mixed fuel, comprising the following steps: uniformly mixing wheat straw powder and lignite powder to obtain a mixture, drying the mixture at 200-270°C for 25-30 minutes in a flue gas atmosphere, and cooling to room temperature to obtain a flue gas modified wheat straw and lignite mixed fuel. The fuel quality and physical properties of the flue gas modified wheat straw and lignite mixed fuel are improved. The combined quality improvement method can compensate for the loss of combustible components during the drying process, enhance the hydrophobicity of the flue gas modified wheat straw and lignite mixed fuel while improving the quality of the combined quality improved fuel, effectively improve the combined utilization value of lignite and wheat straw, significantly reduce the emission of NOx from the combustion product, and reduce pollution, effectively improve the utilization value of wheat straw and lignite, and achieve efficient energy saving and carbon reduction at the production capacity end.

The present application relates to the technical field of metal material plating, in particular to a kind of γ-TiAl material turbine blade sawtooth crown wear-resistant coating plating method, it includes multi-station special plating device and aviation kerosene oxygen mixed fuel supersonic flame spraying process.Plating device is divided into two kinds of linear arrangement and annular arrangement, respectively realize 15 pieces and 30 pieces of blade one time clamping plating, significantly improve efficiency;Device realizes accurate positioning and non-spraying area protection by positioning block, pressing plate assembly and other structures.Co-Mo-Cr-Si wear-resistant coating is plated by using supersonic flame spraying process, heat input is low, coating is dense, and bonding strength is high;Subsequent grinding processing makes coating surface roughness reach Ra<0.8 μm.The present application solves the problem of high heat input and low construction efficiency in the prior art, and meets the requirements of high precision and high reliability for aeroengine.

The application discloses a kind of layer board type ammonia-hydrogen mixed fuel nozzle, the nozzle includes bottom platform, cover and flow guide column, the fixed end and ammonia fuel import end of the flow guide column, the fixed end of the flow guide column is fixedly connected with cover, and the ammonia fuel import end of the flow guide column extends outward and penetrates bottom platform;The middle part of the flow guide column is provided with a plurality of ammonia fuel outlets;Flow guide column between bottom platform and cover is provided with by a plurality of first flow guide plate and second flow guide plate alternately arranged and formed layer board stack;The bottom platform is also provided with a plurality of hydrogen fuel inlet channels.The layer board type ammonia-hydrogen mixed fuel nozzle of the application is formed by layer board stack etched with multiple flow channels, and the function of directly injecting and mixing ammonia and hydrogen two fuels without mixing container can be realized.

The invention discloses a fuel detergent, a preparation method thereof and a mixed fuel. The fuel clearing agent comprises a clearing agent main agent and an optional auxiliary agent, and the clearing agent main agent comprises a pentene amine compound, polyether amine and a phenylacetone compound. The pentene amine compound, the polyether amine and the phenylacetone compound are combined, the pentene amine compound, the polyether amine and the phenylacetone compound are mixed for use to generate a synergistic effect, the cleaning effect of the fuel detergent can be remarkably improved, the polyether amine provides good dispersity and solubility, the phenylacetone compound can be fully dispersed in fuel, and the cleaning effect of the fuel detergent is improved. The ketone group of the phenylacetone compound can further enhance the removal capability of polyether amine to specific pollutants and improve the cleanliness of the fuel, and the pentene amine compound is combined, so that the combustion efficiency can be further improved and the emission of harmful gas can be further reduced.

The invention relates to the technical field of integrated energy system dispatching, in particular to an integrated energy system low-carbon dispatching method considering fuel gas hydrogen mixing and carbon transaction, which comprises the following steps of: constructing an integrated energy system model containing electric power, thermal power, natural gas and coupling equipment, and defining an electric hydrogen production process and an electric methane production process of power-to-gas equipment by the coupling equipment model; a fuel gas mixed hydrogen energy flow calculation model is constructed, a decomposition solution method is adopted for iterative convergence and dynamic calculation of a mixed fuel gas real-time heat value, and energy balance constraints are improved; constructing an optimal scheduling model considering the stepped carbon transaction, and taking the minimization of the total operation cost as a target; and applying hydrogen mixing proportion upper limit constraint, and cooperatively deciding power distribution and a hydrogen storage tank charging and discharging strategy through an optimization algorithm to solve a target function. According to the method, the energy flow calculation precision and the renewable energy consumption capability are improved, and collaborative optimization of system economy and environmental protection benefits is realized.

The invention provides a ship ammonia gas mixed fuel and a safe release device thereof, the ship ammonia gas mixed fuel comprises a first adjusting mechanism and a second adjusting mechanism, the first adjusting mechanism is mounted in a cabin, and a storage mechanism for storing ammonia gas and a combustion improver is mounted in the cabin; the top end of the cabin is provided with an air inlet mechanism used for increasing the internal ventilation of the cabin and supplying fuel oxygen, and the air inlet mechanism is communicated with a mixing mechanism used for mixing fuel gas and air; a pressure relief mechanism used for exhausting is installed at the bottom end of the cabin, and the pressure relief mechanism communicates with the rotary drum and the second communicating pipe. The ship ammonia gas mixed fuel and the safe release device thereof have the advantages that the fuel concentration is reduced, fire is prevented, and the fuel is rapidly discharged from the interior of a ship body.

Whether the co-firing ratio is low or high, interlock control is appropriately implemented when the co-firing ratio fluctuates due to the influence of external disturbances. [Solution] This application relates to a gas turbine control device for controlling a gas turbine equipped with a fuel supply system that supplies a first mixed fuel of a first fuel and a second fuel to a first fuel nozzle. The gas turbine control device determines whether or not interlock control of the gas turbine is necessary by comparing the deviation between a target mixing ratio, which is a target value for the mixing ratio of the second fuel in the first mixed fuel, and the mixing ratio of the second fuel in the first mixed fuel, with a reference value. The reference value for determining whether interlock control is necessary differs between the first mixing ratio region, where the combustibility index of the first mixed fuel decreases with increasing mixing ratio, and the second mixing ratio region, where the combustibility index of the first mixed fuel increases with increasing mixing ratio.

The utility model relates to the technical field of cement production, and provides an ammonia-coal mixed fuel cement clinker calcining system which comprises a rotary kiln, a smoke chamber and a decomposing furnace which are sequentially connected. A sufficient combustion area and an ammonia gas pre-decomposition-NOx reduction area are formed in the decomposition furnace, and the sufficient combustion area is located at the downstream of the ammonia gas pre-decomposition-NOx reduction area; the rotary kiln and the ammonia gas predecomposition-NOx reduction area are both connected with an ammonia-coal mixture feeding module used for introducing ammonia gas, pulverized coal and a primary air mixture, the rotary kiln is provided with a secondary air inlet, and the sufficient combustion area is provided with a pulverized coal inlet and a tertiary air inlet. According to the system for calcining the cement clinker by using the ammonia-coal mixed fuel, the ammonia and the coal powder are mixed for use, so that the use of fossil fuel can be reduced, the emission of greenhouse gas CO2 in the calcining process of the cement clinker is reduced, the cost is lower, and meanwhile, the problem that a large amount of NOx is generated by combustion of the ammonia gas is solved.

The invention discloses a garbage incinerator combustion regulation and control system based on sludge atomization spraying and a regulation and control method, and belongs to the technical field of garbage combustion treatment. The regulation and control system comprises a garbage incinerator, a combustion monitoring unit, a dry sludge storage bin, a wet sludge storage bin, a sludge drying unit, a calculation control unit, a dry sludge feeding control unit and a wet sludge feeding control unit. The regulation and control method comprises the steps that the garbage incinerator is started; starting a combustion monitoring unit and a calculation control unit; the dry sludge is uniformly sprayed on a garbage bed layer through the dry sludge feeding control unit, and the overall regulation and control of combustion are realized from a fuel end; the wet sludge is accurately sprayed to an overtemperature area through a wet sludge feeding control unit, and the local temperature is reduced through heat absorption in the evaporation process; and the system automatically realizes closed-loop feedback and dynamic optimization. According to the method, the dual purposes of mixed fuel combustion stability and hearth local temperature field optimization control are achieved, and efficient and stable operation of the incineration process is effectively guaranteed.

The invention discloses a mixed fuel explosion limit rapid prediction and visual platform construction method, and relates to the technical field of explosion limit prediction modeling, and the method comprises the steps: obtaining a multi-source sample data set which comprises the explosion state labels of a plurality of mixed fuels under the conditions of different temperatures, pressures, equivalence ratios and diluent gases; based on the multi-source sample data set, performing training and hyper-parameter optimization on at least one machine learning classification model to obtain a trained explosion limit prediction model; obtaining state parameters of to-be-predicted mixed fuel input by a user through the constructed visual interaction platform, and calling the trained explosion limit prediction model to process the state parameters through the visual interaction platform to obtain an explosiveness prediction result; and carrying out fusion display on the explosiveness prediction result and an explosion limit distribution diagram generated based on the multi-source sample data set on a visual interaction platform. According to the invention, the efficiency and accuracy of mixed fuel explosion limit prediction are obviously improved.

The invention discloses a fuel supply device and a mixed fuel engine test bench, the fuel supply device comprises a raw material supply module, a fuel mixing module, a first conveying pipeline, a second conveying pipeline and a third conveying pipeline, the raw material supply module comprises a first fuel module and a second fuel module; the fuel mixing module comprises a mixed fuel storage tank and a weighing device, the weighing device is used for obtaining the mass change of the mixed fuel storage tank, the first conveying pipeline is connected between the first fuel module and the mixed fuel storage tank, and the second conveying pipeline is connected between the second fuel module and the mixed fuel storage tank. According to the invention, the weighing device is used for weighing the mixed fuel storage tank, so that the mixed fuel with an accurate proportion can be obtained in a test room, the waiting time cost in the test process is reduced, and the test efficiency is improved. The problem that the transportation cost and the transportation risk of the mixed fuel needed by the test are high is solved.

The present invention discloses a mixed fuel burner, comprising an outer tube, a preheating tube, and a fuel delivery tube. One end of the preheating tube is connected to a fuel supply device; a fan is provided at one end of the outer tube, and a tail nozzle is provided at the other end of the outer tube; a multi-stage catalytic injection device is provided in the center of the outer tube; a catalyst chamber is provided in the tail nozzle, and the other end of the preheating tube is connected to the catalyst chamber; one end of the fuel delivery tube is connected to the catalyst chamber; the multi-stage catalytic injection device includes several stages of catalytic injection components, each of which is provided with a catalyst cavity, a central heat storage body is provided in the catalyst cavity; a second catalyst is installed in the catalyst cavity; an annular gap is formed between the side of the central heat storage body and the inner wall of the catalyst cavity; a supporting connecting tube is provided between two adjacent stages of the catalytic injection components; and a thermal catalytic cover is provided around the supporting connecting tube between the two adjacent stages of the catalytic injection components. The present invention can promote the vaporization and cracking of the mixed fuel, improve the combustion efficiency of the mixed fuel, and save the use of the mixed fuel.

A method for combustion of an ammonia mixed fuel, according to one embodiment, comprises: a fuel adjustment step of preparing a mixed fuel containing ammonia and hydrogen by mixing ammonia and hydrogen such that hydrogen is mixed in an amount in excess of gaseous ammonia on a volume basis; and a combustion step of supplying the mixed fuel and oxygen to an ammonia combustion catalyst to perform combustion.

An internal combustion engine system (100) is described herein. An internal combustion engine system (100) uses one or more fuels that may be hydrophilic. The system uses a water measurement sensor to determine the water concentration in the hydrophilic fuel. To meet the power demand, the system uses the measured water concentration to modify the data stored in the fuel map (136). The fuel map (136) provides a pump speed and a fuel mixing ratio with respect to a given power level to the controller (134). The system receives the data and modifies the data based on the measured water concentration.

A method of operating a rotating detonation combustor includes providing a flow of air through an air inlet to flow into a detonation chamber, providing a flow of fuel from at least one fuel injector into the detonation chamber, mixing the flow of the fuel and the flow of the air in the detonation chamber to generate a fuel-air mixture, detonating the fuel-air mixture in the detonation chamber to generate rotating detonation waves within the detonation chamber, and controlling, during operation of the rotating detonation combustor from a first power operating state to a second power operating state, different from the first power operating state, the air inlet wall to control the flow of the air through the air inlet into the detonation chamber to control a discharge coefficient and an operating mode within the detonation chamber.

The invention relates to the technical field of liquid fuel engines, in particular to a valve injection structure integrated igniter which comprises a first valve shell, a second valve shell, a first hollow valve element assembly, a second hollow valve element assembly, a fluid driving assembly and a spark plug. When the second hollow valve element assembly moves upwards to jack up the first hollow valve element assembly, gas fuel enters the gas-oxygen channel, liquid fuel enters the kerosene channel, and the gas fuel and the liquid fuel are mixed at outlets of the kerosene channel and the gas-oxygen channel and then enter the fuel gas channel for ignition. Synchronous control over the first valve rod is achieved by controlling the second valve rod, so that propellant injection in the vapor-liquid dual-element propellant assembly is controlled at the same time, the response time of fuel injection is shortened, and reliable ignition is achieved.

The invention relates to a combustion system for mixed fuel of hydrogen and fuel gas, a secondary pipeline and a main pipeline are vertically arranged, the secondary pipeline is arranged between a natural gas box body and a combustor, an inlet flow-equalizing mixing device is arranged in the main pipeline, the inlet flow-equalizing mixing device is of a blade structure, and the blade device is arranged on the upstream of the secondary pipeline. The blade structure is provided with a plurality of blades, the connecting line of the two ends of each blade is perpendicular to the central axis direction of the secondary pipeline, the extending direction of each blade is perpendicular to the central axis direction of the secondary pipeline, the distances between the adjacent blades are different, and the farther the distance from the secondary pipeline is, the smaller the distance between the adjacent blades is. According to the combustor capable of directly mixing the fuel, natural gas and hydrogen can be mixed in equal proportion through the arrangement of the distance between the blades, the situation that the proportion of local natural gas and hydrogen is different can be avoided, the combustion efficiency can be improved, and accidents are avoided.

The application discloses a cold-state testing device and method for ammonia-coal mixed fuel turbulent flow, wherein, during the testing process, media with different particle sizes are configured into testing media according to a preset mixing ratio of ammonia-coal fuel, the testing media is carried by primary air into a primary air pipe and into a chamber from an outlet end of the primary air pipe, and secondary air enters into an annular space through a cyclone and is mixed with the testing media entering from the primary air pipe. In this way, the actual mixing state of ammonia-coal mixed fuel in a burner is simulated. A laser Doppler wind speed measuring device is mainly used for measuring the average speed of gas phase / solid phase, the average speed of radial / tangential direction, the root mean square speed, the root mean square speed of radial / tangential direction and the average particle size distribution of particles in the burner, so that the turbulent flow characteristics of the ammonia-coal mixed fuel in the burner are obtained, the change rule of the turbulent flow characteristics in the burner is clarified, and the burner is designed and optimized.

The invention discloses an energy-saving and carbon-reducing method for thermal power generation, which relates to the technical field of thermal power generation and comprises the following steps: S1, flue gas pretreatment: performing pretreatment such as denitration, dust removal and desulfurization on flue gas discharged by a boiler of a power plant; s2, coal gas conversion is conducted, specifically, pipe surrounding is conducted on a coal gas conversion furnace, and filtered and discharged high-temperature waste gas about to enter an air pre-heater is pressurized through an induced draft fan and then sent to a decomposition position; s3, waste gas decomposition and mixing treatment is conducted, specifically, waste gas is introduced into each decomposition mixed fuel generating furnace through a waste gas operation pipeline and then sprayed into the furnace by controlling a flow gate valve, fuel in the decomposition mixed fuel generating furnace is set off C, and CO2 gas in the decomposition mixed fuel generating furnace is continuously decomposed till the CO2 gas is reduced into CO; s4, waste steam washing is conducted, specifically, waste steam obtained after C0 reduction is washed, particulate matter is used for conducting waste gas shearing and waste heat decomposition on waste gas, a combustible gas source is synthesized through temperature difference cooperation, and carbonization is achieved; and S5, waste gas recycling. The method saves energy and reduces carbon emission.

To provide an ammonia mixed combustion engine that enables operation at any ammonia mixed fuel burning ratio and can improve a combustion stability and an exhaust gas property.SOLUTION: An ammonia mixed combustion engine 1, which operates by combusting ammonia and hydrocarbon system liquid fuel, causes a control unit 2 to implement at least one of lowering or raising the air excess ratio in the fuel, advancing or retarding the injection timing of the liquid fuel, and lowering or raising the injection pressure of the liquid fuel, in accordance with an increase or decrease in a mixed fuel combustion ratio of ammonia in the fuel.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of solid waste resource utilization and fuel preparation, and particularly relates to a method for preparing fuel oil from waste plastics or waste rubber. Comprising the following steps: S1, pretreating raw materials; s2, loading materials; s3, mechanochemical conversion: carrying out mechanical ball milling to break and convert molecular chains of the waste plastics or the waste rubber; and S4, product separation: carrying out solid-liquid separation on the ball-milled system, and collecting to obtain the hydrocarbon mixed fuel oil which is in a liquid state or a half-flow state at normal temperature. The method can be used for treating polyolefin and rubber wastes and a mixed system thereof, and is close to an actual complex waste plastic source; additional high temperature and organic solvents are not needed, the process is simplified, and energy consumption and environmental burden are reduced; under the synergistic effect of mechanochemistry and catalytic regulation, a normal-temperature flowable oil product can be stably obtained, and the carbon number and molecular weight distribution are more adaptive to the application scene of fuel oil; and reduction and high-value utilization of the waste plastics are realized, and a supplementary source is provided for fuel oil.

The utility model discloses a pilot deflagration ignition device system, which relates to the technical field of petrochemical torch combustion ignition systems, and comprises an incandescent light deflagration ignition pipeline, a pilot deflagration ignition pipeline, a pilot deflagration ignition pipeline and a pilot deflagration ignition pipeline, one end of the deflagration ignition ring pipeline is connected with the deflagration ignition ring pipe; an outlet of the deflagration mixed fuel gas unit is respectively connected with an incandescent light deflagration ignition control valve and an incandescent light deflagration ignition ring control valve, the incandescent light deflagration ignition control valve and the incandescent light deflagration ignition ring control valve are arranged in parallel, the incandescent light deflagration ignition control valve is connected with an incandescent light deflagration ignition pipeline, and the incandescent light deflagration ignition ring control valve is connected with a deflagration ring ignition pipeline; an inlet of the deflagration ignition unit is respectively connected with an air inlet pipe and a fuel gas inlet pipe; the control unit is in control connection with the incandescent light deflagration ignition pipeline, the deflagration ignition ring pipeline, the deflagration mixed fuel gas unit and the deflagration ignition unit; the ignition device system is simple in structure, successful ignition can be completed in a remote automatic or manual mode, and successful ignition can be completed in an on-site automatic or manual mode.

A fuel system includes a first fuel subsystem having a supply of a first fuel and at least one fuel pump to provide a high-pressure feed of a first fuel and a low-pressure feed of the first fuel. The fuel system also includes a second fuel subsystem having a supply of a second fuel, and a plurality of fuel injectors. Each fuel injector forms a high-pressure fuel inlet, a low-pressure fuel inlet, a second-fuel inlet, and a combined-fuel outlet passage. A first fuel admission valve is movable to admit the first fuel into the combined-fuel outlet passage displacing some of the second fuel to form a combined fuel charge. A second fuel admission valve admits the second fuel to the combined-fuel outlet passage. The first fuel may include a compression-admission fuel such as diesel, and the second fuel may include an alcohol fuel such as methanol. Providing the first fuel at two different fuel pressures enables the first fuel to serve lubrication and cooling purposes within fuel injector, whilst also providing a component of a segmented combined fuel charge or substantially all of a fuel charge.