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Knowledge related to light hydrocarbons: What are light hydrocarbons? Answer: “Hydrocarbons” refer to a series of substances formed by the combination of carbon and hydrogen in various proportions. The lighter portion of these is called light hydrocarbons. The main component of natural gas is C1, with a small amount of C2; the main components of liquefied petroleum gas are C3 and C4. These substances are in gaseous state at normal temperature and pressure, and are known as gaseous light hydrocarbons. Hydrocarbons with carbon numbers from C5 to C16 are in a liquid state at normal temperature and pressure; we refer to them as liquid light hydrocarbons. The lightest components in liquid light hydrocarbons are C5 and C6; saturated C5 and C6 are the best raw materials for bubble gas production. The heavier components include gasoline, kerosene, and diesel, among others. What is light hydrocarbon gas? Answer: It refers to a combustible gas formed by gasifying light hydrocarbon fuels using processing equipment and mixing them with air, which meets the requirements of the Standard for Classification of Urban Gas GB/T13611. Does a light hydrocarbon gas generation device fall under the category of pressure vessels? Answer: Since the design pressure of the light hydrocarbon gas generation device is 0.095 Mpa, and the operating pressure is generally no more than 0.03 Mpa, it does not fall under the category of pressure vessels. Are there diverse sources for light hydrocarbon gas? What are the requirements for the raw materials? Answer: The raw materials used for producing light hydrocarbon gas come from a wide range of sources, primarily oil (gas) fields, refineries, solvent oil plants, petrochemical plants, and natural gas purification facilities. Liquid light hydrocarbons with a density of 0.63–0.68 kg/L, a 50% evaporation temperature not exceeding 75°C, a 90% evaporation temperature not exceeding 135°C, and a total sulfur content of no more than 0.04% can all be used as raw materials for gas production. Such as dewaxed oil and light naphtha produced by refineries, petroleum ether produced by solvent oil plants, stable light hydrocarbons and natural gasoline produced by oil (gas) fields, and \"bottoms oil\" produced by natural gas purification plants. What is the basic structure of a light hydrocarbon gas generation device? Answer: The light hydrocarbon gas generation unit consists of nine components: the main system, the fuel supply system, the reheating system, the control system, the detection and alarm system, the lightning and static electricity protection system, the gas system, the oxygen content analysis system for the gas, and the air system. Under operational conditions, the pressure in the distribution network ranges from 0.01 to 0.03 MPa, with the maximum pressure not exceeding 0.045 MPa ； The rated pressure for cooking appliances (stoves, water heaters) is 1000±200 Pa. The diameter of the outdoor main distribution pipelines is determined based on the number of users and the distance over which the water needs to be transported; seamless steel pipes are used for these pipelines, which are connected by welding. The indoor pipes are galvanized pipes, connected by welding and threading. The design, construction, and regulations for liquefied petroleum gas and natural gas pipelines are the same. When natural gas needs to be connected, no changes are required to the indoor or outdoor piping systems. Why is the main unit in light hydrocarbon gas generation devices buried directly in the ground? Answer: The main unit is installed by direct burial. According to regulatory requirements, this approach allows for a reduction in the fire separation distance, and it also helps to prevent temperature changes from affecting the calorific value of the light hydrocarbon gas. Can stoves and water heaters be used interchangeably? Answer: Artificial gas, liquefied petroleum gas, natural gas, and light hydrocarbon gases have different calorific values and combustion potentials, so they cannot be used interchangeably; each requires specialized stoves and water heaters. Existing stoves and water heaters can be used after appropriate modification. Competent manufacturers in China are able to produce qualified stoves and water heaters based on the calorific value and combustion potential of light hydrocarbon gas. Its various parameters can match the combustion characteristics of light hydrocarbon gas, ensuring complete combustion as well as economic efficiency and reliability. What are the advantages of light hydrocarbon gas generation devices? Answer: Light hydrocarbon gas generation units have advantages such as small land footprint, low investment costs, short construction time, small fire separation requirements, flexibility in site installation, safe operation, simple handling, easy maintenance, manageable operation, few personnel needed to oversee the facility, and low work pressure. What are the differences in the economic comparison between light hydrocarbon gas and liquefied petroleum gas? Answer: (1) Economic comparison between bottled liquefied petroleum gas and light hydrocarbon gas: Based on a price of 48 yuan per bottle (13 kilograms) for liquefied petroleum gas, 1 kilogram of liquefied petroleum gas is roughly equivalent to 2.1 m3 (5000 Kcal/m3) of light hydrocarbon gas. If a household uses one bottle of liquefied petroleum gas per month, the cost is 48 yuan; under the same conditions, the cost of using light hydrocarbon gas is around 35 yuan. (2) Economic comparison between pipeline liquefied petroleum gas and light hydrocarbon gas: Assuming a price of 10 yuan per m3 for pipeline liquefied petroleum gas, 1 m3 of this gas is equivalent to approximately 4.6 m3 (5000 Kcal/m3) of light hydrocarbon gas; thus, the price of 1 m3 of liquefied petroleum gas, when converted to the price of 1 m3 of light hydrocarbon gas, is about 2.17 yuan. It can be seen that light hydrocarbon gas is more economical than liquefied petroleum gas. In addition, there are several issues associated with the use of liquefied petroleum gas: first, the quality of domestically produced liquefied petroleum gas is poor, it contains a lot of residue, and its volume is insufficient ； Second, changing the bottle every time causes a lot of trouble for users, especially those living on higher floors ； Third, although pipeline liquefied petroleum gas avoids many of the inconveniences associated with bottled supply, the system pressure at the gas supply stations is high, and these stations are located on the ground, which poses a significant risk ； Fourth, containers for transporting, storing, and vaporizing or liquefying liquefied petroleum gas are all pressure vessels, which must be regularly inspected as required by regulations ； Fifth, the fire separation requirements are strict, making it difficult to locate sites within residential areas. Heating systems using light hydrocarbon gas, and an economic comparison between heating with light hydrocarbon gas, heating with liquefied petroleum gas, and urban centralized heating? Answer: There are two forms of heating using light hydrocarbon gas: First, the unitized household heating system. In this system, each residential unit is equipped with a gas heating stove (water heater) in the kitchen or balcony, which serves as a source of heat for heating and hot water for daily use. The gas for these heating stoves comes from light hydrocarbon gas supply stations. This wall-mounted heating furnace installed in residential homes boasts many advantages, such as high efficiency, adjustable temperature, fast heating, and safety in use. The modular light hydrocarbon gas heating system can reach the desired temperature as per the household’s requirements, with no restrictions on the heating period. It features high thermal efficiency and no losses associated with heat distribution networks. When no one is at home, a lower temperature can be set, and by using temperature control valves in front of the radiators in each room, it is possible to maintain different temperatures in various rooms, thereby reducing unnecessary heat loss and saving energy. Due to the small water capacity in the system and limited heat storage, it heats up quickly, allowing the heat to disappear when people leave and to return once they return. It is relatively easy to use, has many years of operational experience abroad, and represents a mature and practical technology. The investment cost for individual unit heating is much lower for real estate developers compared to the costs associated with expanding urban centralized heating systems, as well as compared to the investment costs involved in installing boiler rooms within residential complexes for heating purposes. In unit-based individual heating systems, the use of smart (IC card) gas meters for charging gas fees eliminates the drawbacks associated with the previous centralized heating billing system. Economic analysis of unit-type light hydrocarbon gas heating: (1) Heating boilers (water heaters) The heating boilers (water heaters) available on the market currently vary greatly in terms of quality and price, ranging from 2,500 to 10,000 yuan per unit. Heating boilers (water heaters) costing 5,000 yuan or less per unit generally have a power rating of 18 kilowatts (15,480 kcal/hour) or less. These heating boilers (heat exchangers) come equipped with two systems: one for heating and another for providing hot water for daily use, so users do not need to purchase a separate water heater for bathing purposes. They are capable of heating areas of 120–200 m2, with an average investment cost of around 25–42 yuan per m2. It is much lower than the investment in centralized urban heating and heating provided by boiler rooms built within residential complexes (60–70 yuan/m2). (2) Operating cost analysis: ① In a high-rise or multi-story residential building, the rooms located at the top end have the highest operating costs; those on the top floors but not at the ends have higher costs, while those in the middle have the lowest costs. ②The operating condition of a heating furnace (water heater) has a significant impact on operating costs; an energy-saving operating mode can save approximately 40% more energy compared to a constant-temperature operating mode. ③In heated rooms, using geothermal radiant heating instead of convective heating from radiators can save approximately 10% more energy under the same operating conditions. ④In a modular light hydrocarbon gas heating system equipped with a powerful thermostat, users can decide on the most economical operating mode based on actual conditions, thereby achieving energy-efficient operation and saving on operational costs; in other words, they can control the temperature as desired. ⑤In actual engineering applications, although individual heating has various advantages, it cannot fully leverage all of these benefits in housing projects such as affordable housing or low-income housing complexes, where outdoor temperatures are low in winter, the heating period is long, and economic constraints are present ； In high-end residential areas and villa complexes with higher economic affordability, the advantages of this heating method are particularly evident, and it is highly popular among real estate developers and users. II. The light hydrocarbon gas boiler centralized heating system relies on a separately built light hydrocarbon gas boiler room within the residential complex to provide centralized heating. This approach is similar to the traditional coal-fired boiler rooms used for centralized heating in residential areas, but the differences between the two are as follows: ① Light hydrocarbon gas boilers allow for automatic control of the return water temperature, enabling adjustment of the heating time; they can start and stop heating on their own, offering high flexibility, energy savings, and low operating costs, making them suitable for various types of residential complexes. ②Light hydrocarbon gas boilers have high thermal efficiency, generally around 90%, and provide high power output. ③Light hydrocarbon gas boiler systems have low overall construction costs, require little space, have few auxiliary facilities and spare parts, resulting in low expenses for daily maintenance. ④Light hydrocarbon gas boilers are easy to operate and do not require specialized personnel for supervision; they can be managed by the staff at the light hydrocarbon gas station, resulting in lower maintenance costs. ⑤Light hydrocarbon gas boilers can also enable \"unit-based individual heating\" through the courtyard heating network. By installing a \"shut-off valve\" or an \"intelligent heating meter\" on the existing heating pipes in the rooms, it is possible to manually regulate the flow of hot water, thus allowing for controlled individual heating. This approach effectively addresses the issue of non-payment for heating services caused by human factors, achieving the goal of ensuring that only those who pay get heating while those who do not do not. ⑥Using light hydrocarbon gas boilers for centralized heating does not cause environmental pollution, and it is in line with **’s environmental protection policies. For district heating boiler rooms built on-site, the costs of boiler rooms and gas supply systems using either light hydrocarbon gas or liquefied petroleum gas are roughly the same, and both are below 30% of the cost associated with urban centralized heating systems. However, the operating costs associated with light hydrocarbon gas are about 28% lower than those using liquefied petroleum gas. Compared to the heating price of 4.67 yuan/m2·month in the Shenyang area, where no financial subsidies are provided, this results in a reduction of 2.06 yuan/m2·month; whereas compared to the average heating price of 2.55 yuan/m2·month in areas where financial subsidies are still available, there is an increase of 0.06 yuan/m2·month. How large is the footprint of a light hydrocarbon mixed gas supply station? Answer: Depending on the size of the gas supply station, the smallest ones cover an area of 34.62 m2, while the largest ones cover an area of 240 m2. Does light hydrocarbon mixed gas condense during transmission, distribution, and use? Answer: To facilitate users and ensure that raw materials can be obtained locally, many factors must be thoroughly considered in the design of the gas supply system. Different control methods are required for raw materials of varying densities, and this is where the technological innovation lies. As long as the operating procedures are followed, no condensation will occur during transmission, distribution, and use. Why cannot crude C5 be used in the ethylene process? Answer: Crude C5 contains a high level of unsaturates, has a complex composition, and also includes diolefins, natural gums, sulfides, and other substances. A high amount of sulfides results in a strong odor; they not only cause corrosion to equipment and pipes but also irritate human sensory organs. Since crude C5 must come into contact with large amounts of air during the gas production process, this accelerates the oxidation and polymerization reactions of dienes, resulting in the formation of viscous and asphalt-like substances that can clog pipes, air nozzles, and other components. Therefore, crude C5 cannot be used as a raw material for gas production. How much light hydrocarbon gas can each household use for normal cooking over a month? Answer: The amount of gas used by residential users for normal cooking each month is influenced by many factors, such as the number of people in the household, climate conditions, standard of living, and living habits. According to statistical data from Hohhot, Taiyuan, Shijiazhuang and other cities, each household (with about 3 members) consumes approximately 23–28 m3 of light hydrocarbon gas per month for normal cooking purposes.