Under certain temperature and pressure conditions, the coal is thermally processed with a gasifying agent to convert the coal into a combustible gas.
At present, there are four types of industrialized gasification: fixed bed gasification (including atmospheric pressure, pressurization, solid-state ash discharge and liquid ash discharge), fluidized bed gasification (normal pressure and pressure), and entrained flow gasification ( Atmospheric pressure and pressure) and molten bed gasification (normal pressure).
Classification according to different gasification media, including the following:
(1) The gas produced by the fixed-bed coal gasifier with air gas as the gasification medium has a low calorific value.
Water gas: A technique in which water vapor is added to an air blast to produce a mixed producer gas to supply a raw material gas for producing ammonia and methanol.
(2) Coal hydrogenation In order to increase the methane content in the gas, hydrogen gas is used as a gasification medium under pressurized conditions, which strengthens the gasification furnace production capacity and simplifies the gas purification step.
2. Liquefaction
Coal conversion technology for producing clean liquid fuels and chemical raw materials from solid coal. Can be divided into direct liquefaction, indirect liquefaction two categories.
Several methods have been developed for direct liquefaction. The well-known processes include solvent refined oil method (SRC-1, SRC-2), hydrogen supply solvent method (EOS), and hydrogen coal method.
Indirect liquefaction includes the Mobil process, which converts methanol to high-quality gasoline, and the one- and two-stage process technologies for synthesizing gasoline from syngas.
Liquefaction technology is still in the research and experimental stage in China.
3. Coking
Using coal as raw material, coke is produced by high-temperature dry distillation, coal gas and coal tar are obtained at the same time, and coal conversion technology of other chemical products is recovered.
The main products of coking coke for blast furnace ironmaking, can also be used for casting non-ferrous metal smelting, preparation of calcium carbide, carbon disulfide, elemental phosphorus. The second product is coal tar, which is a raw material for the pharmaceutical, dye and explosive industries after separation and purification by the industrial sector. Coke oven gas and chemical products such as ammonia, benzene, sulfur and thiocyanate are products in the gas purification process. The purified gas is meso-heat value gas, and the calorific value is about 17 500 MJ/m3. Gas 300-400m3 is a gaseous fuel for the steel industry. It can also produce hydrogen and methane after separation.
1, What is Cold Room ?
Cold room is a building warehouse using refrigeration machine cold room units to reach a certain temperature and has insulation to hold the temperature.
It is also a constant temperature and humidity storage room for foods, liquid, chemical, pharmaceutical, vaccine, scientific experiments and other items. The refrigeration system of the cold room is still a core component of the construction of the entire Cold Storage Room.
2, Cold room classification:
According to the structure
â—‡ Civil engineering cold room building
â—‡ Steel structure cold room
â—‡ Mixed structure
Mobile cold room, Modular cold room and cold room container.
According to the cold room usage
â—‡ Production type cold room used in food, meat, fish factory
â—‡ Distribution type cold room used for logistics
â—‡ Retail cold room used for supermarket
â—‡ Household cold room
According to the cold room scale
â—‡ Large cold storage over 10,000 tons
â—‡ Medium-sized cold storage 1000-10,000 tons
â—‡ Small cold storage less than 1000 tons
According to the cold room temperature
◇ High temperature cold room Chiller Room design temperature (-2~8°C)
◇ Medium temperature cold room design temperature (-10~-23°C)
◇ Low temperature cold room Freezer Room design temperature (-23~-30°C)
◇ Ultra-low temperature cold room design temperature (-30~-80°C)
According to the cold room goods
â—‡ Seafood and meat cold room
â—‡ Dairy and ice cream cold room
â—‡ Fruit and vegetables cold room
â—‡ Pharmaceutical and chemicals cold room
â—‡ Flower cold storage
3, Cold room refrigerant choice
â—‡Ammonia: the oldest in history, the best choice in the field of industrial refrigeration worldwide. Due to the characteristics of the ammonia system, it is generally used for centralized refrigeration, with a special machine room for large-scale refrigeration systems (more than 10,000 tons of cold storage). There is a trend toward miniaturization and modulation, with an emphasis on improving safety and reducing the amount of charging.
â—‡ Freon: It is widely used in cold storage to disperse refrigeration. It is suitable for small and medium-sized cold storage and large-scale cold storage with limited ammonia. For environmental protection, large-scale cold storage The Freon system should be avoided as much as possible.
â—‡ CO2: The cold storage application is mainly based on cascade system and loading system. The low-temperature field is more suitable for cascade. The high-temperature field is suitable for loading. The cascade system is more expensive than the traditional ammonia and Freon system.
4, Cold room defrosting ways
Hot-gas defrosting
Water defrosting
Electricity defrosting
How is a cold room designed?
A good design of these rooms considers not only the selection of equipment, but its location for a safe access of the personnel. To ensure a safe access and maneuver into the cold room, it is necessary that contractors, engineers and owners participate in the project to determine the selection of a cooling system determined by analyzing life cycle cost and energy efficiency.
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