AU2009100157A4 - Apparatus and method for the thermo-chemical conversion of fuel raw materials into mechanical or electric energy - Google Patents

Description

Title of the invention: Apparatus and method for the thermo-chemical conversion of fuel raw materials into mechanical or electric energy Inventor 1.Inventor Name / Title Dr.-Ing. Berkan First name Jens Street address 42 Schofield CCT Address, Suburb Caboolture, QLD 4510 Country AUSTRALIA Nationality German / Australian Proportion of invention [%] 100 Signature Page 1 / 17 Definition: Symbol Description Unit N Running number, index X1 Interface X2 Interface 4,. Fuel gas mass flow Kg/s m, Exhaust gas mass flow Kg/s 410 Fuel mass flow Kg/s rn Gas mass flow Kg/s Heat flow kJ/s Page 2 / 17 Description [0001] The present invention relates to a combustion engine which is integrated into an apparatus or a plant to generate mechanical power, thermal power or both. The mechanical power can either be used directly to propel consumers, or indirectly to generate electric energy or other forms of energy to drive consumers. The thermal power can either be used directly by plant internal or plant external consumers or be directly discharged or be transferred to other components or sub-assembly of the power generation plant or external assemblies. Preferred the combustion engine can be integrated into a plant, generating fuel gas from a fuel gas generator which can be for example a gasifier for the gasification of various solid fuels preferred such as bio fuels from wood or other sources but not limited to this. The present invention is a novel design and method to integrate and optimize the functionality and the design of combustion engines into such power plant systems, preferably small scale systems within the power output range below 200 kW mechanical but not limited to this. The combustion engine will feature a single unit circulation loop for the engine's lubricant, also acting as engine and system coolant fluid, also acting as heat exchanger fluid, also acting as thermal buffer, capable of operating at various temperature levels to enable optimized operating conditions for the whole power plant. State of the art [0002] It is now known that combustion engines for traction or industrial purpose in general feature two separate closed fluid circuits. One close fluid circuit represents the oil lubrication circuit and the other one the coolant circuit. Typically the lubrication fluid is an engine oil and can be situated either directly in the oil pan attached to the bottom of the engine or the engine can feature a dry sump, where the oil volume storage is separated from the combustion engine but connected with pump devices and hoses respectively pipes. The coolant circuit typically features a mixture of water and glycol or similar chemicals to enhance the temperature range and the corrosive protection ability of the coolant fluid. Typically the engine's lubrication fluid pump is housed directly in the engine and driven by the crankshaft. Typically the engine's coolant fluid pump is housed in the front end accessory drive of the engine and driven by the belt, propelled by the crankshaft. Typically this differentiation and split of the two different fluid circuits is a very good solution for common applications as e.g. vehicle or truck applications where for safety and cost reasons (crash event, risk of fire, environmental pollution etc) a water based coolant circuit is preferred and where for cost and weight reasons as well as for design integration reasons the volume of engine lubricant is to be minimized, hence requiring regular service and change. Page 3 / 17 Background and description of the invention [0003] The aim of the invention is to modify the existing conventional traction or industrial combustion engine design as described in [0001] and [0002] to enable the optimized usage in combination with fuel gas generators (e. g. gasifiers) and system integration respectively plant integration for stationary purpose such as e. g. power plants and mobile purpose such as e. g. traction of vehicles or boats. [0004] Another most important aspect is the robustness of the modified engine fluid circuit in terms of maintenance free operation time, variability of operation points to optimize the whole system including sub-systems and components such as, but not limited to, combustion engine, gasification unit, heat exchangers for solid, liquid and gaseous fuels and oxidizing agents, heat consumers, mechanical and other power consumers. Also the invention will increase the reliability and cost effectiveness of sub-components and the whole system. Ideally, the invention will allow independent adjustment of temperature levels of the fluid within the different interconnected sub systems and therefore of the sub-systems themselves, volume flow rates between the sub-systems and also it will enable monitoring of fluid consumption or leakage, of fluid state of health, for instance contamination with particles or foreign chemical materials, ageing etc. By this, the whole system shows a feature to instantly react to (and to optimize for) different conditions of environment, fuel, wear, health (e. g. partial plugging), load, dynamics, variation in heat consumer requirements etc. [0005] Therefore, in view of the foregoing, it is desirable to have an improved combustion engine lubrication system that solves these and other problems of the prior art. [0006] Therefore, in view of the foregoing, it is desirable to have an improved combustion engine coolant system that solves these and other problems of the prior art. [0007] Therefore, in view of the foregoing, it is desirable to have an improved integrated thermal network between the sub-systems and the consumers that solves these and other problems of the prior art. [0008] Therefore, in view of the foregoing, it is desirable to have an method of control and regulation for the control of all aspects of the improved integrated thermal network between the sub-systems and the consumers that solves these and other problems of the prior art. This includes the temperature level and the volume flow of the combined lubrication-coolant fluid within a broad range. While the lowest possible temperature will be given by the viscosity behavior of the fluid, the highest possible temperature will be given by the thermal stability of the fluid. Typical values Page 4 / 17 .) / I I are for instance a lowest operating temperature of -40 deg C for a OWXX oil and a highest temperature in excess of 160 deg C for synthetic oil. [0009] Therefore, the primary feature or advantage of the present invention is an improved lubrication and cooling circuit, featuring an integrated thermal network for the connected sub-systems, allowing broad variation of temperature levels and heat flow rates, economical to operate and durable in use. [0010] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the solid fuel pre-conditioner of the gasifier respectively gasification unit. [0011] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the oxidizing agent of the gasifier. [0012] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the fuel gas cooler. [0013] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the intake air of the combustion engine, which for instance is to prevent from throttle icing or engine ventilation icing. [0014] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the lubrication circuit of the combustion engine. [0015] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the cooling circuit of the combustion engine. [0016] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the exhaust heat exchanger of the combustion engine. [0017] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the waste heat exchanger of the system. [0018] Another more specific feature or advantage of the present invention is the provision of thermal energy allowing broad variation of temperature and heat flow rate to the heat storage device of the system. Page 5 /17 V1 It [0019] These and the other features or advantages of the present invention are described and claimed in the following. [0020] The embodiment of the combustion engine (1) modification exemplarily shown in figure 1 employs a modified dry sump lubrication circuit (2). The lubrication oil intake nozzle is directly connected with the fresh oil intake pipe (3). The fresh oil intake pipe can feature an oil filter element (4) and an additional oil pump (5). In this case it can replace the combustion engine internal oil pump (0). Inside the combustion engine the spilled oil flows back to the bottom of the sump where a suction pump (6) will remove it from the dry sump. An oil fill sensor (7) inside the dry sump can monitor the oil level and control the volume flow of the suction pump (6) as well as monitor the state of function of the pump to enable emergency shut off as a safety feature. The removed oil by the suction pump (6) will then be pumped through the outlet pipe (8) which can feature a series of oil filter elements (9) which is preferable dimensioned in a way that redundancy applies in case of partial plugging as well as change intervals are optimized. This can be achieved by employment of pressure sensors (10) to measure the flow resistance of the filter elements. The suction pipe also can feature a heat exchanger (11) while it is possible to integrate the heat exchanger before, after or parallel to the oil filter elements. The fresh oil intake pipe (3) can be connected to the fluid reservoir (12). The outlet pipe (8) can be connected to the fluid reservoir (12). [0021] The embodiment of the combustion engine (1) modification exemplarily shown in figure 1 also employs a modified engine cooling circuit (13). The modifications can either employ the conventional belt driven engine coolant pipe (14) to pump the oil through the engine's cooling circuit or this pump can be replaced by an external, electric driven coolant pump (15). It is also possible to employ multiple pumps for the reason of redundancy or a combination of both, belt driven and external pumps. The engine's coolant oil inlet (17a) is directly connected with the fresh oil intake pipe (16). The fresh oil intake pipe can feature an oil filter element (4) and the mentioned external oil pump (15). The cooling oil flow will cool the combustion engine and in exchange heat up. The ratio between engine load and coolant volume flow will determine the heat and temperature increase of the cooling oil inside the engine. Therefore these values are depending on the coolant temperature at the engine's inlet (17a), and the cooling oil outlet temperature at the engine's coolant outlet (17b). A number of actuated valves and throttles will allow splitting the outlet cooling oil flow into separate partial oil flows to utilize separate heat transfer functionalities as cooling and heating of connected sub-components and internal external devices. [0022] By actuation of valve (18) and (1 8a) a variable portion of the outlet cooling oil flow can be directed to the engine's exhaust gas heat exchanger (19) and then further to multi-position valve unit (20). The multi-position valve unit can control N Page 6 / 17 separate fluid flows with N between N=1 and N=x. Actuating the bypass valve (23) allows to incremental bypass the engine's exhaust gas heat exchanger (19) for enhanced control of temperature and heat flow. The multi-position valve unit (20) allows to control and to manipulate the oil and heat flow to different sub-systems, assemblies and devices. As one feature, an arbitrary portion of the oil and heat flow can be directed to the gasifier heat exchanger (21) where it can be used to pre-heat the gasifier (22) itself or the oxidizing agent (23) to control and manipulate the performance of the gasification process. As another feature, an arbitrary portion of the oil and heat flow can be directed to an external heat exchanger (24) for heat disposal. As another feature, an arbitrary portion of the oil and heat flow can be directed to an external heat exchanger (25) for customer specific usage. As another feature, an arbitrary portion of the oil and heat flow can be directed to a heat energy storage device which can employ a phase changer material (26) and which can be connected to different heat consumers. [0023] In figure 1 the combustion engine is driving an electric generator (27). Between the gasifier's fuel gas outlet pipe (X1) and the combustion engine's air-fuel gas inlet (X2), typically a series of apparatus exist to condition the gas flows. Figure 2 shows exemplarily such series of devices located between (X1) and (X2). Following the connecting interface (X1) the fuel gas passes a de-duster (28) and a filter unit (29) with integrated heat exchanger (30). Integration of a blower (31) allows compensation of pressure losses. The intake air passes the intake air heat exchanger (33) and gets mixed with the fuel gas in the fuel gas air mixer (32) and will be transferred into the combustion engine via connection interface (X2). The solid fuel treatment unit (34) prepares the fuel prior discharging into the gasifier. This includes transportation, which can preferred be achieved by utilizing a screw conveyor or other means. It also includes drying and heating of the fuel to its specific optimal properties in terms of water content, temperature and other features. To achieve this in an optimal way, the fuel treatment unit (34) features an integrated heat exchanger, transferring heat from the closed oil circuit to the fuel. To adjust and control the temperature and the amount of transferred heat, the heat exchanger of (34) is connected either to multi-position valve unit (20) or to the multi-valve unit (35), which can also be designed as a multi-position valve unit, or to another control valve, located at another position of the closed oil circuit. [0024] While combustion engines feature a minimum oil consumption depending on the mode of operation, the average typical oil consumption is about 1 g per kWh mechanical energy produced. Therefore the closed oil circuit features devices to control the amount of circulating oil. Figure 3 shows as an example that this can be achieved by measuring the oil level of the fluid reservoir (12) with a suitable measuring device (36). If the oil level is lowering to a specific level, then pump (42) will be activated to refill (12) with fresh fluid from the storage containment (40) through the pipe arrangement (41). (41) can also employ an additional filter element (43). The amount of refilled fluid will also be controlled by (36). The pipe Page 7 / 17 0/ I arrangement (37) in conjunction with pump (38) can be used to actively reduce the amount of fluid in reservoir (12) in order to enable refilling with fresh fluid from (40) in order to maintain a minimum oil quality by "toping up", while the schedule to practice this can be a complex function of ageing factors of the oil which can be calculated from the duty cycle of the combustion engine respectively the whole power plant. To obtain a closed loop waste management, the oil discharged via pump (38) can also be dosed and added to the solid fuel entering the gasifier. In figure 3 this is exemplarily given in (39), adding the fluid to the solid fuel within the fuel treatment unit (34). It can also be added at other locations. [0024] It is favorable to minimize the amount of fluid pumps, valves, filters and pipes by optimizing the functional integration. For instance, pump 38 and pump 42 can be one, utilizing an intelligent shift schedule of actuating valves, switching between the two functions (refilling the reservoir (12) from storage (40)) and (lowering the fluid level in the reservoir (12) for partial fluid disposal via addition to the gasifier primary fuel). [0025] A major advantage of the invention is that one single fluid can be used to lubricate and cool the combustion engine within a broad temperature range. Typically this range can be as low as -40 deg C and as high as 160 deg C. Conventional water based coolant fluids build up a high system pressure when heated above 100 deg C. The usage of engine oil as coolant prevents from building up system pressure. Independent of the fluid temperature the system pressure maintains stable at the range of ambient pressure. This independency of the fluid gas pressure enables another engine health monitoring function. Monitoring the coolant system pressure, a potential leakage can be easily detected. It is preferable to always maintain a minor vacuum in the coolant system to prevent fluid being spilled into the environment through leakage. If the vacuum cannot be maintained, two possible leakage failure modes become likely. First, if the coolant circuit pressure will rise to a stable level in the range of ambient pressure, then it is likely that the circuit has a leakage to the ambient. By activating the fluid control valves, an intelligent detection function can isolate the separate coolant flow circuits to detect the faulty sub-circuit. This can then be switched off and the total power plant system can run into a stable and maybe power reduced "limb home" mode. The second detectable failure mode is a leakage of the engine's head gasket. If the coolant circuit gets pressurized above ambient pressure, then it is likely that the head gasket is damaged. Monitoring the amount of pressure build up in conjunction with the monitoring of the oil consumption will allow to predict the remaining life time of the combustion engine to schedule a required service. [0026] Another advantage of this invention is that a potential failure of the engine's head gasket will not automatically result in a major break down, as lubricant and coolant are the same and no pressure exists in the coolant circuit. This will allow additional cost saving by utilizing more cost effective material for the engine build. Page 8 / 17 [0027] Another advantage of this invention is that within the thermal network each heat flow can be controlled separately with regard to temperature and volume flow. This will allow complex controlling of the whole system in order to optimize the state of function of each sub-system depending on different factors in order to optimize the operation of the whole plant. [0028] Another advantage of this invention is that the large fluid volume of the combined oil circuit allows for very large service intervals. It is achievable to operate the plant continuously without oil services for the whole life time of the combustion engine. Page 9 / 17

Claims (21)

1. Integrated combustion engine characterized by the fact that the engine's oil lubrication circuit and the engine's coolant circuit are interconnected by elimination of the water-glycol based coolant fluid and utilization of one single oleaginous fluid source for engine lubrication and engine cooling in both engine's lubrication circuit and engine's coolant circuit.

2. The integrated combustion engine of claim 1 integrated into a stationary or mobile power plant, further comprising a storage device for the oleaginous fluid, further comprising a variable controllable fluid pump providing variable fluid flow from the storage device for the oleaginous fluid to the engine's coolant circuit.

3. The integrated combustion engine of claim 1 integrated into a mobile, traction force generating device, further comprising a storage device for the oleaginous fluid, further comprising a variable controllable fluid pump providing variable fluid flow from the storage device for the oleaginous fluid to the engine's coolant circuit.

4. The integrated combustion engine of claim 1, 2, 3 further comprising a storage device for the oleaginous fluid, further comprising a variable controllable fluid pump providing variable fluid flow from the storage device for the oleaginous fluid to the engine's lubrication circuit.

5. The integrated combustion engine of claim 1, 2, 3, 4 further comprising a variable controllable fluid pump attached to the sump of the combustion engine, further comprising a fluid level sensor in the sump of the combustion engine, further comprising a pipe or hose attached to the pump for the recirculation of the fluid into the storage device for the oleaginous fluid, further comprising a filter element attached to this pipe or hose, further comprising pressure sensors attached to the filter element, further comprising a heat exchanger attached to the pipe or hose.

6. Method and procedure to activate and de-activate the fluid pump of claim 5 triggered by fluid level thresholds detected by the fluid level sensor in the sump to evacuate the sump and to pump the oleaginous fluid back to the fluid storage device, further hereby passing through the oil filter elements and the heat exchanger, further comprising the activation of a trigger signal to a central plant operation control module if the pressure drop over the filter elements exceeds a threshold.

7. The fluid storage device of claim 2, 3, 4 further comprising a sensor to measure the fluid level of the oleaginous fluid inside the storage device, further comprising a sensor to measure the pressure inside the storage device, further comprising a sensor to measure the temperature inside the storage device, further comprising a droplet and foam separator, further comprising a vacuum evacuation pump. Page 10 / 17

8. Method and procedure to operate a vacuum pump according to claim 7, maintaining a mild vacuum below ambient pressure under stationary operation conditions in the fluid storage device, to measure the pressure in the fluid storage device with the means of claim 7, further compromising the activation of a trigger signal to a central power plant operation control module if the pressure in the fluid storage device exceeds a threshold.

9. Method and procedure according to claim 8, further comprising a multi-threshold detection algorithm detecting the time related gradient of pressure change, and comparing the measured pressure with the ambient pressure to detect, determine and distinguish a leakage in the combustion engine's head gasket or in peripheral cooling circuit components and transmitting related data to the central power plant operation control module.

10. Method and procedure according to claim 8, further comprising a multi-threshold detection algorithm detecting the time related gradient of oil level change, to transmit related data to the central power plant operation control module.

11. Method and procedure according to claim 9, 10, further comprising an algorithm to assess and evaluate the data delivered to the central power plant operation control module according claim 9, 10, to calculate by means of comparing, integrating and differentiating to determine critical operation conditions to determine the following measures: normal operation mode, a controlled power plant shut down, "limb home operation" with reduced performance, setting signals for service requirement, calculating remaining operation time before service.

12. Method and procedure to measure the engine's coolant circuit outlet temperature by direct measurement or calculation based on engines load and coolant circuit inlet temperature.

13. The stationary or mobile power plant according to claim 2, 3, further comprising at least one of the following heat exchangers: liquid-to-solid mass heat exchanger between the engine's coolant circuit and the solid fuel feed device for the gasifier, liquid-to-gas heat exchanger between the engine's coolant circuit and the oxidizing agent for the gasifier, liquid-to-gas heat exchanger between the engine's coolant circuit and the fuel gas produced by the gasifier, liquid-to-gas heat exchanger between the engine's coolant circuit and the engine's fresh air intake, liquid-to-gas heat exchanger between the engine's coolant circuit and the environment to dispose waste heat, liquid-to-gas heat exchanger between the engine's coolant circuit and an external user to dispose useable heat, liquid-to liquid heat exchanger between the engine's coolant circuit and an external user to dispose useable heat, liquid-to-phase-change element heat exchanger between the engine's coolant circuit and a thermal energy storage device, further comprising control valves to adjust and to bypass the mass and energy flow through the described heat exchangers, preferred independently. Page 11 / 17 LI I1

14. Method and procedure to calculate an optimum engine's coolant circuit inlet and outlet temperature based on at least one of the combustion engine operation performance parameter and power plant operation performance parameter: knocking (spark retardation), lubrication circuit temperature, oil consumption, operating hours, remaining time before service, rpm, torque, ambient temperature, solid fuel moisture content, gasifier efficiency, combustion engine efficiency, total energy conversion efficiency, fuel-air-mixture inlet temperature, caloric heat value of the fuel gas, thermal power requirement of the heat exchangers according to claim 13.

15. Power generation plant with integrated combustion engine, characterized by the fact that the fuel for the combustion engine is a gaseous fuel produced in a fuel gasification unit (gasifier) by the gasification of solid or liquid fuels, further characterized by the fact that the inlet delivery system for the oxidizing agent for the gasifier is coupled to a heat exchanger, further characterized by the fact that this heat exchanger is a liquid to gas heat exchanger or a gas to gas heat exchanger or a combination of both, further characterized by the fact that the fuel for the gasification process is a solid or liquid fuel, processed and preconditioned in a fuel conditioning unit (solid fuel feed device) comprising a heat exchanger, whereby the thermal energy provided by this heat exchanger can be provided by a gaseous heat source or a liquid heat source or a combination of both, further comprising an injection nozzle to inject a fluid into the fuel conditioning unit, further comprising an apparatus to mix the fuel with the injected liquid, whereby the liquid is exhausted waste oil from the combined engine lubrication and cooling circuit or any other liquid.

16. Method and procedure to calculate and to dispose an optimum amount of waste oil through the injection nozzle into the fuel conditioning unit (solid fuel feed device) according to claim 15, based on at least one of the combustion engine operation performance parameter and power plant operation performance parameter: knocking (spark retardation), lubrication circuit temperature, oil consumption, operating hours, remaining time before service, rpm, torque, ambient temperature, solid fuel moisture content, gasifier efficiency, combustion engine efficiency, total energy conversion efficiency, fuel-air-mixture inlet temperature, caloric heat value of the fuel gas. Page 12

/ 17 Definitions 0 Pump 1 Combustion engine 2 Dry sump lubrication circuit 3 Fresh oil intake pipe 4 Filter element 4a Filter element 5 Pump 6 Suction pump 7 Oil level sensor 8 Outlet pipe 9 Filter element 10 Pressure sensor 11 Heat exchanger 12 Fluid reservoir 13 Engine cooling circuit 14 Engine coolant pipe 15 Electric coolant pipe 16 Fresh oil intake pipe 17a Engine coolant inlet 17b Engine coolant outlet

18 Valve 18a Valve

19 Exhaust gas heat exchanger

20 Multi position valve unit

21 Gasifier heat exchanger 22 gasifier 23 Oxidizing agent 24 External heat exchanger 25 External heat exchanger 26 Phase changer material for heat storage 27 Electric generator 28 De-duster 29 Filter unit 30 Heat exchanger 31 Blower 32 Fuel gas air mixer 33 Heat exchanger 34 Solid fuel treatment unit 35 Multi-valve unit Page 13 /17 I -T I I 36 Measuring device 37 Pipe arrangement 38 pump 39 Solid fuel treatment unit with integrated fluid mixer 40 Fluid storage containment 41 Pipe arrangement 42 pump 43 Filter element 50 Heatexchanger X1 Interface X1 Interface Page 14 /17