Petrochemical industry is an industry with high energy consumption and high pollution emissions, and the development and application of energy-saving and consumption-reducing technologies are very important, and the application of energy-saving and consumption-reducing technologies has promoted the development of energy-saving and environmental protection in the petrochemical industry. Today I have brought you some principles and cases of energy-saving and consumption-reducing technologies, let's learn them together!
Plate air cooling technology 1Technical principle.
The plate air cooler adopts the all-welded plate bundle as the heat transfer unit structure, and the LT corrugated plate as the heat transfer element.
Because the corrugation of the plate increases the heat transfer due to the flow between the fluid and the plate, the turbulent flow is formed at a very low Reynolds number, which greatly improves the heat transfer efficiency. The static agitation of the corrugated plates also reduces fouling.
Due to the overlapping of plates, the veneer heat exchange area is large, and the heat transfer efficiency is high, under the condition of completing the same heat exchange, the plate air cooler is small in size and light in weight, and the equipment installation space can be greatly saved after use.
2.Energy saving and emission reduction effect.
Taking the application of plate air cooler in the 600,000 t a gas separation unit of an oil refinery as an example, the energy-saving effect and economic benefits that this technology can produce are illustrated. Compared to wet air cooling, the plate air cooler is 48 percent lighter6%, and the floor area is reduced by 722%, water consumption reduced by 665%, saving 60 operating costs3%。During the operation cycle, the total investment was saved by 583%, the economic benefits are very significant.
The thermal combination of the device and the heat supply technology is to output the heat of the excess heat to another set of devices as a heat source to heat the process medium, and its starting point is to find a suitable heat match in the large system to achieve the purpose of energy optimization and utilization.
Hot supply is a form of thermal combination, which is the material supply relationship between two or more sets of devices: that is, the product flow of the upstream device is not cooled or completely cooled, nor is it sent to the intermediate tank for storage and then pumped to the downstream device, but directly (or through 1 thermal buffer tank) to the downstream device as feed.
In this way, the cooling and reheating of the material can be avoided, and the secondary heat transfer (fire) loss of the heat exchange network can be reduced.
High-efficiency heating furnace ash removal technology, gas shock wave soot blowing technology:
The technology is to create a controlled fuel detonation to produce a supersonic shock wave of controlled intensity – a shock wave.
The violent pressure pulsation longitudinal wave of the shock wave produces a kind of first pressure and then pulling effect on the ash accumulation, so that the ash on the heating surface is broken, peeled off and separated from the ash substrate by the impact of the shock wave.
Sootblowing technology:
Sonic sootblowing uses the principles of acoustics, vibration and fatigue to send a certain intensity of sound waves into the ash accumulation area in the furnace during operation.
The intense and rapidly changing vibrations of the sound waves cause the air molecules in these areas to oscillate with the ash particles, and the ash particles collide with each other, causing the ash attached to the heated surface to break away from the heated surface and levitate.
Under the action of sound waves, the ash and scale are peeled off from the heating surface and taken out of the flue to achieve the purpose of ash cleaning.
Chemical Cleaning Technology:
Taking the atmospheric and vacuum device as an example, in the process of shutdown of the device, catalytic diesel is introduced after the system is withdrawn as a cleaning carrier, and the original equipment and processes such as heating furnace, circulating pump, tower and tank of the device are used to establish local circulation.
When the temperature reaches about 130, a certain amount of oil-soluble cleaning agent is injected into the circulation system, and the cleaning agent has the effect of soaking and dissolving the oil stain, and the oil stain is removed with the circulating flow.
* Ash Cleaning Technology:
In the start-up state, CH ash cleaning agent should be applied to remove the ash and scale to avoid the occurrence of unplanned shutdown of the device.
The chemical agent decomposes at high temperature, and the decomposition products under the action of the catalyst are alkaline oxides, nitrogen and oxygen. It is equivalent to supplementing oxygen during the combustion process of the heating furnace. This results in more adequate fuel combustion to reduce the generation of CO and S and solid carbon.
At the same time, the basic oxides can also react with the acid gases in the flue gas. Brittle, non-viscous inorganic salts are generated, which in turn prevents acid gases from being adsorbed onto the heating surface and corroding equipment.
The molten inorganic salt has the effect of removing the ash, it can form a mixture with the hard ash on the pipe wall, and the mixture with the low eutectic point becomes a liquid and falls off after melting. On the other hand, when nitrate meets sulfur and carbon, a micro-explosion also occurs, forming a microshock wave that sheds the unmelted hard sediment.
The new enhanced heat transfer burner technology allows the fuel to be fully pre-ignited in the pre-combustion chamber, and the venturi effect at the outlet of the combustion chamber greatly increases the throat injection velocity of the flame, thus forming a strong low-pressure area at the radiant bottom.
Under the dual action of the jet of high-speed flame and the low-pressure area, the high-temperature flue gas convection circulation in the radiation chamber is formed, which makes the airflow in the furnace more uniform and prolongs the residence time of the high-temperature flue gas in the furnace radiation chamber, so that the convective heat transfer ratio of the radiant chamber of the heating furnace is greatly increased.
Therefore, the inhomogeneity of the axial and radial thermal intensity of the radiant chamber of the traditional heating furnace is reduced to a large extent, so as to effectively improve the heat transfer efficiency of the radiant chamber.
Two-stage condensation process technologyAt present, the design of the coking main fractionation column of the delayed coking unit mostly adopts the first-stage condensation scheme. In order to reduce the absorption and stabilization of part of the load, save energy and reduce consumption, a two-stage condensation scheme of coking fractionation tower was proposed.
The specific process is as follows: the oil and gas at the top of the coking fractionation tower are cooled to 80 90 by the cooler and then enter the first-stage oil-water separation tank at the top of the fractionation tower, and the oil and gas at the top of the first-stage oil-water separation tank are condensed to 40 into the second-stage oil-water separation tank, and the gasoline at the bottom of the first-stage oil-water separation tank is pumped out and the stable gasoline mixture of the outlet device is cooled as a product sent out device, and the top of the second-stage oil-water separation tank is enriched with gas into the rich gas compressor, and the crude gasoline reaches the absorption tower by the crude gasoline pump. At the same time, this technology is also suitable for catalytic fractionation and absorption stabilization systems.
Compared with the cold high-resolution process, the hot high-resolution process requires the addition of some high-pressure equipment, and the process is more complex. Under the same conditions, the heat load of the air cooler of the reaction product of the hot high-separation process is much smaller than the heat load of the air cooler of the reaction product of the cold high-resolution process, which is equivalent to the excess of this part of the heat. In addition, the use of thermal high-resolution process can effectively avoid the deposition and clogging of fused cyclic aromatic hydrocarbons in the tube bundle of the reaction product air cooler.
High-efficiency plate heat exchanger technologyThe main technical difference between the plate heat exchanger and the traditional shell and tube heat exchanger is the use of corrugated plates to form the groove of the heat exchanger. These grooves can cause strong turbulence and mixing, resulting in heat transfer efficiency that is 3 to 5 times higher than that of traditional shell-and-tube equipment. Under the same process operating conditions, the fouling rate in a plate heat exchanger can be significantly reduced compared to a shell-and-tube heat exchanger.
The heat exchange area is 297A high-efficiency plate heat exchanger of about 3m2 requires less than 1With a footprint of 49m2, the total floor area (including the working area) is about 93m2。The corresponding tube length is 6The 1m shell and tube heat exchanger has an area of about 14m2, and the total floor area including the working area and the traction of the shell and tube bundle is 55About 8m2.
A large oil refinery in the United States installed 9 plate heat exchangers in the preheating system, and the installed plate heat exchanger increased the temperature at the inlet of the heating furnace by 37 compared with the conventional shell and tube heat exchanger8℃。
Ultrasonic anti-scale technology ultrasonic pulse oscillation wave propagates in the heat exchanger tube and plate wall, and produces an effect between the metal tube, plate wall and the nearby liquid medium, destroys the adhesion conditions of the dirt, prevents the heat exchange equipment from forming during operation, improves the heat transfer capacity of the heat exchange equipment, reduces the energy consumption required to meet the same process requirements, and achieves the purpose of energy saving.
The two-stage liquid ejector vacuum technology uses liquid as the power medium, and the circulating liquid is sprayed out at high speed from the nozzle, forming a negative pressure area below the nozzle, pumping the gas into the mixing chamber of the injector, and generating a vacuum at the gas suction inlet.
The gas-liquid mixture then enters the separator, separating the gas-liquid phases and leaving the system after the gas is pressurized. The circulating liquid is pumped out from the bottom of the separator, cooled and transported to the nozzle of the ejector to form a jet cycle. The heat generated during the solution circulation and gas pressurization process, as well as the heat brought in by the gas, is carried by the circulating solution and removed from the system in the air cooler or water cooler.
Membrane technology for treatment and reuse of refinery water, which mainly includes ceramic membrane oil and iron removal technology, composite membrane treatment technology, interception and oil removal technology, active molecular membrane ultra-micro filtration combined multi-functional fiber adsorption technology. Taking ceramic membrane oil and iron removal technology as an example, when the emulsifiable concentrate (particle size is 100 m), dispersed oil (particle size is 10 100 m), and emulsified oil (particle size is 0.) in the condensate1-10 m), when iron and suspended impurities pass through the ceramic membrane tube filter, the ceramic membrane tube will play the role of bridging, intercepting and blocking filtration, so that oil, iron and suspended impurities stay on the filter membrane, and water passes through the filter membrane.
After being treated by ceramic membrane oil and iron removal technology, the oil content and iron content of condensate increased from 756 mg L, 108 g L to 056mg/l、14μg/l。The oil removal rate and iron removal rate were achieved respectively. 04%, there was no significant change in pH value and total alkalinity, and the conductivity decreased slightly.