CN-121974378-A - Method and system for processing heavy sodium carbonate by nuclear power cogeneration energy supply

CN121974378ACN 121974378 ACN121974378 ACN 121974378ACN-121974378-A

Abstract

The invention discloses a method and a system for processing heavy sodium carbonate by nuclear energy cogeneration energy supply, and relates to the technical field of sodium carbonate production; the method comprises the steps of pretreating brine to obtain refined brine, stripping and decomposing the refined brine by utilizing nuclear power cogeneration steam to obtain concentrated brine with a main component of Na 2 CO 3 , performing multi-effect evaporation on the concentrated brine with the main component of Na 2 CO 3 by utilizing the nuclear power cogeneration steam, separating out Na 2 CO 3 in a crystal form of sodium carbonate Na 2 CO 3 ·H 2 O, performing centrifugal drying treatment on the sodium carbonate crystal and mother liquor together by utilizing the nuclear power cogeneration electric energy, and calcining the dried material by utilizing the nuclear power cogeneration steam to remove crystal water in the dried material to obtain the heavy sodium carbonate Na 2 CO 3 . The invention realizes the increase of the steam production amount of the nuclear reactor and correspondingly reduces the steam power generation amount of the nuclear reactor, thereby reducing a great amount of energy loss generated when low-grade energy is converted into high-grade energy and improving the overall efficiency.

Inventors

QIAO MING
SHAO JIANXIN
LI MING
YU JING
SUN YANBO
ZHOU LIFENG
LI QINGCHUN
ZHANG YUE
PEI GE
MEI DONGLIANG
LIU QING
ZHAO FUJIAN

Assignees

辽河石油勘探局有限公司
中国石油天然气集团有限公司
中油辽河工程有限公司

Dates

Publication Date: 20260505
Application Date: 20241030

Claims (10)

1. The method for processing the heavy sodium carbonate by utilizing nuclear energy cogeneration energy supply is characterized by comprising the following steps of: pretreating brine to obtain refined brine; Stripping and decomposing refined brine by utilizing nuclear power cogeneration steam, decomposing NaHCO 3 in the refined brine into Na 2 CO 3 , simultaneously adding NaOH solution, and reacting NaOH with NaHCO 3 in the concentrated decomposed brine to generate Na 2 CO 3 to obtain concentrated brine with the main component of Na 2 CO 3 ; Performing multi-effect evaporation on concentrated brine with a main component of Na 2 CO 3 by using nuclear power cogeneration steam, namely heating the concentrated brine by using steam to further evaporate and concentrate, wherein Na 2 CO 3 is separated out in a form of sodium carbonate monohydrate Na 2 CO 3 ·H 2 O crystal; Performing centrifugal drying treatment on the monohydrate sodium carbonate crystallization and the mother liquor by utilizing nuclear power cogeneration electric energy; And calcining the dried material by utilizing nuclear power cogeneration steam to remove crystal water in the dried material, thus obtaining the heavy sodium carbonate Na 2 CO 3 .
2. The method for processing heavy sodium carbonate by utilizing nuclear power cogeneration energy according to claim 1, wherein the refined brine is subjected to secondary stripping decomposition by utilizing nuclear power cogeneration steam, wherein in the primary stripping decomposition, the brine is subjected to the action of hot steam, part of NaHCO 3 starts to decompose, na 2 CO 3 generated by decomposition remains in a liquid phase, in the secondary stripping decomposition, the residual NaHCO 3 continues to decompose, naOH solution is added at a secondary stripping decomposition outlet to perform chemical reaction with the residual NaHCO 3 , and NaOH reacts with NaHCO 3 to generate more Na 2 CO 3 and H 2 O.
3. The method for processing heavy sodium carbonate by utilizing nuclear power cogeneration energy according to claim 1, wherein the concentrated brine with the main component of Na 2 CO 3 is subjected to secondary multi-effect evaporation by utilizing nuclear power cogeneration steam, wherein the concentrated brine in the primary multi-effect evaporation is heated and evaporated, and the generated secondary steam is introduced into the secondary multi-effect evaporation for heating the concentrated brine, so that the multi-stage utilization of heat is realized.
4. The method for processing heavy sodium carbonate by utilizing nuclear power cogeneration energy according to claim 1, wherein the brine is pretreated to obtain refined brine in the following manner: Removing suspended matters, partial organic matters, colloid particles and microorganisms in the brine through multi-medium filtration, and realizing deep purification of the brine; The brine filtered by the multi-medium is adsorbed by the activated carbon to remove organic matters, heavy metals, peculiar smell and possible residual tiny particles, so as to obtain refined brine.
5. The method for processing heavy sodium carbonate by utilizing nuclear power cogeneration energy according to claim 4, wherein before multi-medium filtration, partial suspended matters and suspended sediment in brine are removed after the brine is settled, and the purification treatment of brine is realized.
6. A system for processing heavy sodium carbonate by utilizing nuclear power cogeneration energy supply, which is characterized by comprising: The nuclear energy cogeneration steam pipeline is used for providing fresh steam; The nuclear power cogeneration power pipeline is used for supplying power; The pretreatment system is used for pretreating brine to obtain refined brine; The stripping decomposition tower is respectively connected with the pretreatment system and the nuclear power cogeneration steam pipeline, and utilizes fresh steam to carry out stripping decomposition on the refined brine, so as to decompose NaHCO 3 in the refined brine into Na 2 CO 3 , and meanwhile, naOH solution is added, and NaHCO 3 in the concentrated decomposed brine is reacted to generate Na 2 CO 3 , so that concentrated brine with the main component of Na 2 CO 3 is obtained; The multi-effect evaporator is respectively connected with the stripping decomposition tower and the nuclear power cogeneration steam pipeline, and utilizes fresh steam to carry out multi-effect evaporation on concentrated brine with the main component of Na 2 CO 3 , namely, the concentrated brine is heated for further evaporation concentration, wherein Na 2 CO 3 is separated out in a form of sodium carbonate Na 2 CO 3 ·H 2 O crystal; The centrifugal dryer is respectively connected with the multi-effect evaporator and the nuclear power cogeneration power pipeline, residual steam of the nuclear reactor is used for generating electricity, and the electric energy is utilized to jointly carry out centrifugal drying treatment on the monohydrate alkali crystallization and the mother liquor; And the fluidized bed calcining device is respectively connected with the centrifugal dryer and the nuclear power cogeneration steam pipeline, and the fresh steam is utilized to calcine the dried material to remove crystal water therein, thus obtaining the heavy sodium carbonate Na 2 CO 3 .
7. The system for processing heavy sodium carbonate by nuclear power cogeneration energy of claim 6 wherein the stripping decomposition column comprises a primary stripping decomposition column and a secondary stripping decomposition column connected; in the primary stripping decomposition tower, brine is subjected to the action of hot steam, part of NaHCO 3 starts to decompose, and Na 2 CO 3 generated by decomposition remains in a liquid phase; In the second-stage stripping decomposition tower, the residual NaHCO 3 is decomposed continuously, naOH solution is added at the outlet to carry out chemical reaction with the residual NaHCO 3 , and NaOH reacts with NaHCO 3 to generate more Na 2 CO 3 and H 2 O.
8. The system for processing heavy sodium carbonate by nuclear power cogeneration energy of claim 6 wherein the multi-effect evaporator comprises a first multi-effect evaporator and a second multi-effect evaporator which are connected, wherein the first multi-effect evaporator heats and evaporates the concentrated brine, and the generated secondary steam is introduced into the second multi-effect evaporator for heating the concentrated brine to realize multi-stage utilization of heat.
9. The system for processing heavy sodium carbonate by nuclear power cogeneration energy of claim 6, wherein the pretreatment system comprises: the multi-medium filter is used for removing suspended matters, partial organic matters, colloid particles and microorganisms in the brine through multi-medium filtration, so that the deep purification of the brine is realized; And (3) an activated carbon adsorption tank, wherein the brine passing through the multi-medium filter is subjected to activated carbon adsorption to remove organic matters, heavy metals, peculiar smell and possible residual tiny particles, so as to obtain refined brine.
10. The system for processing heavy sodium carbonate by nuclear power cogeneration energy of claim 9, wherein the pretreatment system further comprises: Before multi-medium filtration, the brine passes through a settling tank to remove part of suspended matters and suspended sediments in the brine, so as to realize the purification treatment of brine; A lifting pump is arranged between the brine settling tank and the multi-medium filter, and the lifting pump is connected with a nuclear power cogeneration power pipeline.

Description

Method and system for processing heavy sodium carbonate by nuclear power cogeneration energy supply Technical Field The invention relates to the technical field of trona production, in particular to a method and a system for processing heavy sodium carbonate by utilizing nuclear energy and heat and power cogeneration energy. Background The processing of the trona mainly adopts an evaporation method, and the core equipment is an evaporator. And evaporating and concentrating the trona brine by using heat energy provided by the steam. When the concentration of brine reaches or exceeds the solubility of sodium carbonate, the sodium carbonate precipitates as crystals. The crystals are calcined, dried and cooled to become industrial sodium carbonate, and the industrial sodium carbonate is packaged and sold. In China, the four-effect evaporator and the five-effect evaporator are adopted in the processing of the greenhouse trona, and the multi-effect evaporator and the MVR are adopted in the processing of the tower lignin trona. The multi-effect evaporator mainly relies on fresh steam provided by a boiler to heat and evaporate brine, and the MVR utilizes a high-energy-efficiency compressor to compress and apply work to the steam to convert electric energy into heat energy, so that the recycling of the heat of secondary steam is realized, and the fresh steam is not required to be provided outside. Trona processing plants belong to high energy-consuming enterprises, the energy consumption of which is mainly focused on the steam demand of the alkaline processing technology, and a small part of the energy consumption comes from the electric energy demand of the alkaline processing equipment. The integrated energy consumption per ton of alkali is calculated to be 335 kg of standard coal. At present, large trona processing plants built at home and abroad mostly adopt a coal-fired cogeneration process to provide steam and electric power. Cogeneration has a higher energy utilization than conventional cogeneration (i.e., separate power generation and separate steam generation), and can increase energy efficiency by about 25%. However, there are drawbacks to cogeneration in terms of carbon emissions. The unit carbon emission of the sodium carbonate produced by the natural alkali processing project adopting the coal-fired cogeneration energy supply mode is about 0.91 ton of carbon dioxide equivalent per ton of alkali. If the annual carbon emission of a trona processing plant reaches 91 ten thousand tons of carbon dioxide equivalent calculated by million tons of soda production energy, the problem of carbon emission reduction is difficult to solve by adopting a coal-fired cogeneration energy supply mode. The principle of the small nuclear reactor is that the nuclear fission releases heat, and a large amount of steam is generated after the heat exchange to drive a steam turbine to generate electricity. However, the energy conversion efficiency of nuclear power generation is low, being only about 32.5%. Although nuclear power generation belongs to green electricity, near zero emission of carbon dioxide can be realized, the efficiency of a nuclear reactor is difficult to further improve due to the restriction of energy conversion efficiency. In terms of patent search, we find that there are some related patent applications, but these patent applications do not consider new energy sources in energy supply mode, so the carbon emission is still larger. For example: The patent application with the publication number of CN101503204B discloses a wet decomposition and evaporation process for preparing alkali by using alkali halide containing NaHCO 3, which adopts a four-effect five-body vacuum evaporation crystallization process to process heavy sodium carbonate. However, as the wet decomposition and the evaporation concentration process are completed in the same equipment, the wet decomposition process cannot be effectively controlled, so that the wet decomposition rate is low, and the yield of the heavy sodium carbonate is only 60-70%. The patent application with publication number CN109809437A discloses a novel energy-saving environment-friendly heavy sodium carbonate production process and system. The process adopts a two-stage wet decomposition tower and a water alkali crystallizer for production, wherein steam used by the wet decomposition tower and the water alkali crystallizer is secondary steam, and the steam is recycled after the temperature of the steam is increased by a mechanical compression method through a steam compressor. However, the main heat energy of the process still comes from the conversion of electric energy into heat energy, and the consumption of fresh steam is reduced, but the carbon emission is still larger. Patent application CN112850753B discloses a process for producing trona. The process comprises the steps of solution extraction, pretreatment, steam stripping concentration, sodium carbonate decahydrate