In this era of petrochemical industry, people think of the era of high energy consumption and high pollution. Almost all chemical people have the dream of green chemical industry: Someday, wastewater can achieve zero emissions, and chemical plants say goodbye to sewage pipes; waste gas becomes The treasure house of recycling resources no longer pollutes the environment; chemical equipment is successfully weight-reduced, with less energy consumption and more effort. In the future, with the advent of membranes and related new technologies, this dream will be able to shine into reality. Bopet Metallization Base Film,Lightweight Bopet Stretch Film Rolls,Durable Bopet Stretch Film Rolls,Quality Bopet Lamination Film SHAOXING TIANPU PLASTIC PRODUCTS CO.,LTD , https://www.fulingholdinggroup.com
Petrochemical plant no longer has a sewage pipe
“The ultimate goal of wastewater treatment in petrochemical industry is to achieve zero emissions,†said Yan Yanzhai, Secretary-General of the Petroleum and Chemical Membrane Technology Application Committee of the China Membrane Industry Association. “All wastewater is fully reused after treatment, even fresh water It can be supplemented by treated municipal wastewater to minimize water consumption.†But he also pointed out that due to the large amount of wastewater generated in the petrochemical industry, the complexity of the wastewater, and the difficulty in handling, it is necessary to rely on comprehensive measures such as scientific and technological progress, renewal of ideas, and market regulation. Synergies can achieve the ultimate goal of zero emissions.
The chemical wastewater contains up to about 300 components, and it is difficult to achieve the best treatment effect by relying on a single physical chemical, biochemical or membrane separation technology. Dian Yanzhai stated that the current general approach to treating wastewater is to couple various treatment methods to achieve most of the water reuse. 6 years ago, China's refining of 1 ton of oil required 1.5 to 1.6 tons of fresh water; after the implementation of recycling technology, only 0.5 to 0.6 tons of fresh water is currently injected, which is very close to the international advanced level of 0.3 to 0.4 tons.
He added that part of the reuse is only the goal of the current stage. To realize the complete utilization of waste water and zero discharge, it is necessary to use advanced technologies such as reverse osmosis membrane (RO) technology for advanced treatment of wastewater. The resulting RO concentrating water (the industrial wastewater containing high concentrations of salt ions after treatment by the reverse osmosis unit) became the key to zero emissions. At present, the treatment of RO concentrated water is a multi-method collaborative operation. Normally, it is firstly treated with catalytic ozone oxidation, microbiological method, and activated carbon fiber adsorption to reduce the COD and hardness of the water, but in the end, it is inseparable from the membrane. It is hoped that the research and application of membrane distillation technology.
Party Yanzhai said: "With the advancement of membrane materials and application technology, it may be possible to achieve zero emissions after eight or ten years. To put it further, perhaps at that time, petrochemical plants did not have sewage pipes. There is a set of advanced wastewater treatment equipment."
Dang Yanzhai said that at present, foreign countries have begun to treat urban sewage as a supplement to water for industrial production. PetroChina and Sinopec have also begun trials in China. For example, Dalian Petrochemical Company has treated urban sewage for production of water. If the future petrochemical water can be used on a large scale with treated municipal wastewater, the entire industry will take a big step towards green.
Recover more resources from exhaust gas
In addition to wastewater, exhaust gas treatment is also a major problem for the petrochemical industry. Exhaust gas components are complex, and emissions into the air can cause pollution. However, if the useful components are recycled, they can be used as resources. Thus, gas separation membranes have developed rapidly in this area and are widely used for collecting oxygen from air, recovering hydrogen from synthetic ammonia off-gas, and separating hydrogen, ethylene, and propylene gas from oil-cracked gas mixtures.
For example, Dang Yanzhai said that the tail gas of refinery plants contains various components such as C2, C3, hydrogen, methane, chlorinated hydrocarbons, and fluorinated hydrocarbons, which could only be burned or used directly as fuel, polluting the environment and wasting resources. Nowadays, through the coupling of membranes and other methods, the recycling of materials has become a huge resource. It is reported that there are more than 90 sets of catalytic cracking production facilities for refineries across the country, with annual production of more than 4 million tons of dry gas, including 730,000 tons of ethylene, 725 tons of ethane, 110,000 tons of propylene, 110,000 tons of hydrogen, propane, butane, With 140,000 tons of butenes, if it is recycled in large part, it will save more than 4 million tons of light oil that produces ethylene each year. The emission reduction of 1 cubic meter of fluorocarbons has an effect on the greenhouse effect equivalent to a reduction of about 10,000 cubic meters of CO2. With the continuous maturation of membranes and related technologies, more exhaust gas will be turned into a treasure trove of resources in the future, and the discharged exhaust gas will also be less polluting.
The world market for gas separation membranes has a promising future. It reached US$350 million last year and is expected to expand to US$760 million by 2020. The single membrane separation plant will reach a level of several million cubic meters per day. The domestic gas membrane separation market is increasing at a rate of 30% per year. In 2010, the membrane and equipment sales are estimated to be between 450 million and 500 million yuan.
Unit operation will reduce weight
In addition to waste water and exhaust gas, membranes can also demonstrate magic in energy saving and consumption reduction of petrochemical units. The energy consumption of the separation process in the chemical and petrochemical industries accounts for about 70% of the total energy consumption. Membrane separation technology can realize high-precision separation with high efficiency and low energy consumption, and is one of the common technologies for energy saving and consumption reduction in the process industry. It can be expected that as the membrane application technology continues to advance, more and more unit operations will achieve weight reduction.
For example, the pervaporation membrane (PV) separation technology that has emerged in recent years is particularly suitable for the separation of difficult-to-reach mixtures of near-boiling and constant-boiling mixtures. It can be used for the production of anhydrous ethanol from industrial alcohols and can save energy by 75%. % isopropanol produces anhydrous isopropyl alcohol to save energy by 65%, and esterification to produce ethyl acetate can save energy by 58%. At present, there are nearly 400 PV industrial installations in operation around the world. Their applications are mainly focused on the dehydration of organic liquids, and a small amount is used for removing or recycling organics in water. The separation of organic and organic liquid mixtures is still in laboratory research or pilot testing. Phases, including alcohols/benzenes, alcohols/cyclohexanes, benzene (toluenes)/cyclohexanes, xylene isomers, propanol isomers, hexane isomers, and gasoline organic sulfur removal The separation.
Another example is the steam penetration (VP) technology. There are about 420 industrial installations in operation in the world. They are mainly used for monomer recovery in the production of polyethylene, polypropylene, and polyvinyl chloride, and C3 and above gases and acid gases in natural gas production. Removal, recovery of liquefied gas, oil and gas recovery at refinery stations and gas stations, domestic market size is around 50 million yuan/year, and the annual growth rate is 30% to 40%.
In addition, membrane technology has achieved significant results in transforming traditional chemical processes and innovating older ones. Such as pre-concentration of chemical materials, ion-exchange membrane electrolysis to make alkali, membrane purification and concentration of enzymes and proteins, nanofiltration purification of dyes and reagents, pervaporation to ethanol, and membrane separation and catalytic membrane reaction.